WorldWideScience

Sample records for detectors initial evaluations

  1. Positron emission mammography with tomographic acquisition using dual planar detectors: initial evaluations

    International Nuclear Information System (INIS)

    Smith, Mark F; Raylman, Raymond R; Majewski, Stan; Weisenberger, Andrew G

    2004-01-01

    Positron emission mammography (PEM) with tomographic acquisition using dual planar detectors rotating about the breast can obtain complete angular sampling and has the potential to improve activity estimation compared with PEM using stationary detectors. PEM tomography (PEMT) was compared with stationary PEM for point source and compressed breast phantom studies performed with a compact dual detector system. The acquisition geometries were appropriate for the target application of PEM guidance of stereotactic core biopsy. Images were reconstructed with a three-dimensional iterative maximum likelihood expectation maximization algorithm. PEMT eliminated blurring normal to the detectors seen with stationary PEM. Depth of interaction effects distorted the shape of the point spread functions for PEMT as the angular range from normal incidence of lines of response used in image reconstruction increased. Streak artefacts in PEMT for large detector rotation increments led to the development of an expression for the maximum rotation increment that maintains complete angular sampling. Studies with a compressed breast phantom were used to investigate contrast and signal-to-noise ratio (SNR) trade-offs for different sized spherical tumour models. PEMT and PEM both had advantages depending on lesion size and detector separation. The most appropriate acquisition method for specific detection or quantitation tasks requires additional investigation

  2. Accuracy of 16-detector Multislice Spiral Computed Tomography in the initial evaluation of dilated cardiomyopathy

    International Nuclear Information System (INIS)

    Cornily, Jean-Christophe; Gilard, Martine; Le Gal, Gregoire; Pennec, Pierre-Yves; Vinsonneau, Ulric; Blanc, Jean-Jacques; Mansourati, Jacques; Boschat, Jacques

    2007-01-01

    Background: Multislice Computed Tomography (MSCT) recently proved its accuracy in the detection of coronary artery disease (CAD). It can also give information about left ventricular function and venous network anatomy. We here sought to validate a MSCT-based strategy in the initial evaluation of patients with dilated cardiomyopathy (DCM). Methods: 36 patients with DCM underwent cardiac MSCT before conventional coronary angiography with ventriculography. We analysed arterial calcium score (Agatston score equivalent: ASE), coronary stenosis, left ventricular parameters and venous network. Results: The sensitivity of a MSCT-based strategy in detecting significant CAD was 100% and the specificity 80%. The positive and negative predictive values were respectively 67% and 100%. For ASE 1.000, conventional coronary angiography is mandatory due to MSCT's poor interest in such cases; when ASE <1.000, a contrast-enhanced MSCT may, when normal, replace coronary angiography

  3. Fire Emulator/Detector Evaluator

    Data.gov (United States)

    Federal Laboratory Consortium — Description:The fire emulator/detector evaluator (FE/DE) is a computer-controlled flow tunnel used to re-create the environments surrounding detectors in the early...

  4. Wire Probe Antenna (WPT) and Electric Field Detector (EFD) of Plasma Wave Experiment (PWE) aboard the Arase satellite: specifications and initial evaluation results

    Science.gov (United States)

    Kasaba, Yasumasa; Ishisaka, Keigo; Kasahara, Yoshiya; Imachi, Tomohiko; Yagitani, Satoshi; Kojima, Hirotsugu; Matsuda, Shoya; Shoji, Masafumi; Kurita, Satoshi; Hori, Tomoaki; Shinbori, Atsuki; Teramoto, Mariko; Miyoshi, Yoshizumi; Nakagawa, Tomoko; Takahashi, Naoko; Nishimura, Yukitoshi; Matsuoka, Ayako; Kumamoto, Atsushi; Tsuchiya, Fuminori; Nomura, Reiko

    2017-12-01

    This paper summarizes the specifications and initial evaluation results of Wire Probe Antenna (WPT) and Electric Field Detector (EFD), the key components for the electric field measurement of the Plasma Wave Experiment (PWE) aboard the Arase (ERG) satellite. WPT consists of two pairs of dipole antennas with 31-m tip-to-tip length. Each antenna element has a spherical probe (60 mm diameter) at each end of the wire (15 m length). They are extended orthogonally in the spin plane of the spacecraft, which is roughly perpendicular to the Sun and enables to measure the electric field in the frequency range of DC to 10 MHz. This system is almost identical to the WPT of Plasma Wave Investigation aboard the BepiColombo Mercury Magnetospheric Orbiter, except for the material of the spherical probe (ERG: Al alloy, MMO: Ti alloy). EFD is a part of the EWO (EFD/WFC/OFA) receiver and measures the 2-ch electric field at a sampling rate of 512 Hz (dynamic range: ± 200 mV/m) and the 4-ch spacecraft potential at a sampling rate of 128 Hz (dynamic range: ± 100 V and ± 3 V/m), with the bias control capability of WPT. The electric field waveform provides (1) fundamental information about the plasma dynamics and accelerations and (2) the characteristics of MHD and ion waves in various magnetospheric statuses with the magnetic field measured by MGF and PWE-MSC. The spacecraft potential provides information on thermal electron plasma variations and structure combined with the electron density obtained from the upper hybrid resonance frequency provided by PWE-HFA. EFD has two data modes. The continuous (medium-mode) data are provided as (1) 2-ch waveforms at 64 Hz (in apoapsis mode, L > 4) or 256 Hz (in periapsis mode, L < 4), (2) 1-ch spectrum within 1-232 Hz with 1-s resolution, and (3) 4-ch spacecraft potential at 8 Hz. The burst (high-mode) data are intermittently obtained as (4) 2-ch waveforms at 512 Hz and (5) 4-ch spacecraft potential at 128 Hz and downloaded with the WFC

  5. Evaluation Program initiative

    International Nuclear Information System (INIS)

    Rich, B.L.

    1987-01-01

    The purpose of this paper is to provide the Department of Energy's (DOE) safeguards and security community with some insights on an important management initiative by the Office of Security Evaluations (OSE). The paper will present the ''what, where, who, when, and why'' of a new Evaluation Program. The Evaluation Program will be comprised of a continuing series of regular and special evaluations of DOE safeguards and security programs and policies. The evaluations will be integrative and ''crosscutting,'' i.e. will extend across DOE organizational lines. Evaluations will be offered as positive advisories to DOE managers with safeguards and security responsibilities and will not be rated. They will complement the ongoing OSE Inspection Program of inspections conducted by OSE's Inspection Division. The purpose for the evaluations is to establish an accurate and current assessment of the effectiveness and status of safeguards and security programs and policies and to provide DOE managers with required information on program and policy effectiveness

  6. B-physics performance with Initial and Complete Inner detector layouts in Data Challenge-1

    CERN Document Server

    Benekos, N C; Bouhova-Thacker, E; Epp, B; Ghete, V M; Jones, R; Kartvelishvili, V G; Lagouri, T; Laporte, J F; Nairz, A; Nikitine, N; Reznicek, P; Sivoklokov, S Yu; Smizanska, M; Testa, M; Toms, K

    2004-01-01

    The B-physics performance for the Initial and the Complete Inner Detector layouts is presented. Selected types of B-physics events were simulated, reconstructed and analyzed using the software tools of ATLAS Data Challenge-1 (DC1). The results were compared to those obtained with an older ATLAS detector design the so-called TDR layout. Within the limitations of the DC1 software tools an attempt was made to evaluate the performance loss due to missing detector parts in the Initial layout in comparison with the Complete detector.

  7. Impact of reduced-radiation dual-energy protocols using 320-detector row computed tomography for analyzing urinary calculus components: initial in vitro evaluation.

    Science.gov (United States)

    Cai, Xiangran; Zhou, Qingchun; Yu, Juan; Xian, Zhaohui; Feng, Youzhen; Yang, Wencai; Mo, Xukai

    2014-10-01

    To evaluate the impact of reduced-radiation dual-energy (DE) protocols using 320-detector row computed tomography on the differentiation of urinary calculus components. A total of 58 urinary calculi were placed into the same phantom and underwent DE scanning with 320-detector row computed tomography. Each calculus was scanned 4 times with the DE protocols using 135 kV and 80 kV tube voltage and different tube current combinations, including 100 mA and 570 mA (group A), 50 mA and 290 mA (group B), 30 mA and 170 mA (group C), and 10 mA and 60 mA (group D). The acquisition data of all 4 groups were then analyzed by stone DE analysis software, and the results were compared with x-ray diffraction analysis. Noise, contrast-to-noise ratio, and radiation dose were compared. Calculi were correctly identified in 56 of 58 stones (96.6%) using group A and B protocols. However, only 35 stones (60.3%) and 16 stones (27.6%) were correctly diagnosed using group C and D protocols, respectively. Mean noise increased significantly and mean contrast-to-noise ratio decreased significantly from groups A to D (P calculus component analysis while reducing patient radiation exposure to 1.81 mSv. Further reduction of tube currents may compromise diagnostic accuracy. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. The performance of the ATLAS initial detector layout for B-physics channels

    International Nuclear Information System (INIS)

    Epp, B.; Ghete, V.M.; Kuhn, D.; Zhang, Y.J.

    2004-01-01

    At the start-up of LHC one expects parts of the ATLAS detector to be missing. This layout is called initial layout, whereas the fully staged detector is called complete layout. B-physics channels were simulated, reconstructed and analyzed using the software tools of ATLAS data challenge-1 (DC1). The performance of the detector with respect to quantities relevant to the analysis of the B s → D s π channel and the validation of the full chain generation-simulation-reconstruction-analysis were evaluated for the initial and complete layout. (author)

  9. Evaluating Domestic Violence Initiatives

    OpenAIRE

    Parmar, Alpa; Sampson, Alice

    2006-01-01

    This paper critiques the approach of identifying ‘best practice’ projects and discusses the problem with simply transferring projects into different contexts. The argument is illustrated by explaining the evaluation process of three domestic violence projects which all had the same aim, which was to reduce domestic violence. The evaluated projects all delivered advocacy programmes and were located in disadvantaged areas in the United Kingdom. A more suitable evaluation approach is proposed wh...

  10. Multicenter Comparison of Contrast-Enhanced FDG PET/CT and 64-Slice Multi-Detector-Row CT for Initial Staging and Response Evaluation at the End of Treatment in Patients With Lymphoma.

    Science.gov (United States)

    Gómez León, Nieves; Delgado-Bolton, Roberto C; Del Campo Del Val, Lourdes; Cabezas, Beatriz; Arranz, Reyes; García, Marta; Cannata, Jimena; González Ortega, Saturnino; Pérez Sáez, Mª Ángeles; López-Botet, Begoña; Rodríguez-Vigil, Beatriz; Mateo, Marta; Colletti, Patrick M; Rubello, Domenico; Carreras, José L

    2017-08-01

    To compare staging correctness between contrast-enhanced FDG PET/ceCT and 64-slice multi-detector-row CT (ceCT64) for initial staging and response evaluation at the end of treatment (EOT) in patients with Hodgkin lymphoma, diffuse large B cell lymphoma (DLBCL), and follicular lymphoma. This prospective study compared initial staging and response evaluation at EOT. One hundred eighty-one patients were randomly assigned to either ceCT64 or FDG PET/ceCT. A nuclear medicine physician and a radiologist read FDG PET/ceCT scans independently and achieved post hoc consensus, whereas another independent radiologist interpreted ceCT64 separately. The reference standard included all clinical information, all tests, and follow-up. Ethics committees of the participating centers approved the study, and all participants provided written consent. Ninety-one patients were randomized to ceCT64 and 90 to FDG PET/ceCT; 72 had Hodgkin lymphoma, 72 had DLBCL, and 37 had follicular lymphoma. There was excellent correlation between the reference standard and initial staging for both FDG PET/ceCT (κ = 0.96) and ceCT64 (κ = 0.84), although evaluation of the response at EOT was excellent only for FDG PET/ceCT (κ = 0.91). Our study demonstrated satisfactory agreement between FDG PET/ceCT (κ = 0.96) and ceCT64 (κ = 0.84) in initial staging compared with the reference standard (P = 0.16). Response evaluation at EOT with FDG PET/ceCT (κ = 0.91) was superior compared with ceCT64 (κ = 0.307) (P < 0.001).

  11. Multi-detector CT knee arthrography - initial experience

    International Nuclear Information System (INIS)

    Thomson, J.M.Z.; Fallon, M.; Breidahl, W.H.

    2002-01-01

    Full text: Traditional plain film arthrography can achieve reasonable accuracy and is an accepted method of investigation of patients with knee pain and possible meniscal tear. Multi-detector CT can potentially provide a more detailed and accurate examination due to its high-resolution crosssectional and multi-planar capabilities. The aim of this study was to assess the accuracy of our technique. All patients who underwent a multi-detector CT knee arthrogram in an initial 8 month period were identified. Initially the referring clinician was contacted. If the patient was referred to an orthopaedic surgeon the outcome of orthopaedic review was recorded using clinical, arthroscopic and / or MRI follow-up of the patient population. One hundred and twelve patients had a Multi-detector CT knee arthrogram performed within and 8 month period. Follow-up information was received in 69.7% of patients. Of these 68.9% had orthopaedic assessment - of which 69.2% underwent a knee arthroscopy.There was total agreement of findings in 67%, agreement of meniscal findings in 67% and chondral findings in 100%. Overall, orthopaedic opinion agreed with CT findings in 76.9%. At this stage, all meniscal tears not described in the initial CT arthrogram report have in retrospect been visible. Multi-detector CT knee arthrography is an accurate and elegant technique for investigation of knee pain, providing information in a format familiar to those reporting knee MRI. There is an initial learning curve. The technique is particularly useful in chondral assessment. It is accurate for meniscal pathology, although caution and recognition of potential pitfalls is required. Copyright (2002) Blackwell Science Pty Ltd

  12. Initial Ada components evaluation

    Science.gov (United States)

    Moebes, Travis

    1989-01-01

    The SAIC has the responsibility for independent test and validation of the SSE. They have been using a mathematical functions library package implemented in Ada to test the SSE IV and V process. The library package consists of elementary mathematical functions and is both machine and accuracy independent. The SSE Ada components evaluation includes code complexity metrics based on Halstead's software science metrics and McCabe's measure of cyclomatic complexity. Halstead's metrics are based on the number of operators and operands on a logical unit of code and are compiled from the number of distinct operators, distinct operands, and total number of occurrences of operators and operands. These metrics give an indication of the physical size of a program in terms of operators and operands and are used diagnostically to point to potential problems. McCabe's Cyclomatic Complexity Metrics (CCM) are compiled from flow charts transformed to equivalent directed graphs. The CCM is a measure of the total number of linearly independent paths through the code's control structure. These metrics were computed for the Ada mathematical functions library using Software Automated Verification and Validation (SAVVAS), the SSE IV and V tool. A table with selected results was shown, indicating that most of these routines are of good quality. Thresholds for the Halstead measures indicate poor quality if the length metric exceeds 260 or difficulty is greater than 190. The McCabe CCM indicated a high quality of software products.

  13. Evaluation and Evaluating the Community Initiative "URBAN"

    DEFF Research Database (Denmark)

    Alves, Sonia

    2013-01-01

    focus on a more open and democratic process of evaluation. This paper presents and compares different conceptual and methodological frameworks created for the assessment of the European initiative Urban II, including the one that was used by the author in the context of an academic evaluation...... in the city of Porto. The comparative analysis of the results leads us to the recommendation for more democratic processes of evaluation and intervention, in order to improve their quality and accountability and promote the important goal of learning with this type of experimental initiatives....

  14. Teaching Evaluation: Waiting for Initiatives

    Directory of Open Access Journals (Sweden)

    Alejandro Canales Sánchez

    2008-08-01

    Full Text Available In this text, it is sustained that, despite the fact that the teaching activity is one of the main functions of higher education institutions or even the only one in most of them, it hasn’t been reflected in the leading initiatives that have been set in motion in this area for the last two decades. In particular, it points out that the wide evaluation politics established in the education system during the late eighties, didn’t consider the teaching activity as a concern issue for the mechanisms or rewards in the evaluation system. Even though the implementation of new actions tried to repair the situation, mainly by improving the quality of working time and the qualifications of the personnel performing these activities; teaching, in strict sense, and the design or application of a new evaluation scheme to strengthen it, didn’t get better.

  15. Validity of spherical approximations of initial charge cloud shape in silicon detectors

    International Nuclear Information System (INIS)

    Xu Cheng; Danielsson, Mats; Bornefalk, Hans

    2011-01-01

    Spherical approximation has been used extensively in low-energy X-ray imaging to represent the initial charge cloud produced by photon interactions in silicon detectors, mainly because of its simplicity. However, for high-energy X-rays, where the initial charge distribution is as important as the diffusion process, the spherical approximation will not result in a realistic detector response. In this paper, we present a bubble-line model that simulates the initial charge cloud in silicon detectors for photons in the energy range of medical imaging. An initial charge cloud can be generated by sampling the center of gravity and the track size from statistical distributions derived from Monte Carlo generated tracks and by distributing a certain proportion of photon energy into a bubble (68%) and a line portion uniformly. The simulations of detector response demonstrate that the new model simulates the detector response accurately and corresponds well to Monte Carlo simulation.

  16. Initial absolute calibration factors for some neutron sensitive self-powered detectors

    International Nuclear Information System (INIS)

    Kroon, J.

    1975-01-01

    Self-powered flux detectors have found extensive use as monitoring devices in PWR (Pressurized Water Reactor) cores and CANDU (Canada Deuterium Uranium) type power reactors. The detectors measure fuel power distributions and indicate trip parameters for reactor control and safety requirements. Both applications demand accurate absolute initial calibration factors. Experimental results obtained in calibrating some neutron sensitive self-powered detectors is presented. (author)

  17. Evaluation of prototype silicon drift detectors

    International Nuclear Information System (INIS)

    Ellison, J.; Hall, G.; Roe, S.; Lucas, A.

    1988-01-01

    Operating characteristics of several prototypes of silicon drift detectors are investigated. Detectors are made of unpolished silicon produced by the zone melting method and characterized by n-type conductivity and specific resistance of 3.6-4.6 kOhmxcm. The detectors comprise 40 parallel bands of 200 μm width and 1 cm length separated by 50 μm intervals. Data characterizing the potential distribution near anodes under the operating bias voltage, dependences of capacities and leakage as well as the detector space resolution

  18. Initial Measurements on Pixel Detector Modules for the ATLAS Upgrades

    CERN Document Server

    Gallrapp, C; The ATLAS collaboration

    2011-01-01

    Delicate conditions in terms of peak and integrated luminosity in the Large Hadron Collider (LHC) will raise the ATLAS Pixel Detector to its performance limits. Silicon planar, silicon 3D and diamond pixel sensors are three possible sensor technologies which could be implemented in the upcoming Pixel Detector upgrades of the ATLAS experiment. Measurements of the IV-behavior and measurements with radioactive Americium-241 and Strontium-90 are used to characterize the sensor properties and to understand the interaction between the ATLAS FE-I4 front-end chip and the sensor. Comparisons of results from before and after irradiation for silicon planar and 3D pixel sensors, which give a first impression on the charge collection properties of the different sensor technologies, are presented.

  19. Initial Measurements On Pixel Detector Modules For The ATLAS Upgrades

    CERN Document Server

    Gallrapp, C; The ATLAS collaboration

    2011-01-01

    Sophisticated conditions in terms of peak and integrated luminosity in the Large Hadron Collider (LHC) will raise the ATLAS Pixel detector to its performance limits. Silicon planar, silicon 3D and diamond pixel sensors are three possible sensor technologies which could be implemented in the upcoming pixel detector upgrades of the ATLAS experiment. Measurements of the IV-behavior and measurements with radioactive Americium-241 and Strontium-90 are used to characterize the sensor properties and to understand the interaction between the ATLAS FE-I4 front-end chip and the sensor. Comparisons of results from before and after irradiation, which give a first impression on the charge collection properties of the different sensor technologies are presented.

  20. Framework for Evaluation of Equity Initiatives

    Science.gov (United States)

    Bexley, Emmaline; Harris, Kerri-Lee; James, Richard

    2010-01-01

    The Framework for Evaluation of Equity Initiatives has been prepared to support the Go8 Equity Strategy. Its purpose is to assist Group of Eight (Go8) universities to evaluate the effectiveness of their equity initiatives and interventions in the context of federal policies and the distinctive missions and responsibilities of the individual Go8…

  1. Transmutation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Viererbl, L., E-mail: vie@ujv.c [Research Centre Rez Ltd. (Czech Republic); Nuclear Research Institute Rez plc (Czech Republic); Lahodova, Z. [Research Centre Rez Ltd. (Czech Republic); Nuclear Research Institute Rez plc (Czech Republic); Klupak, V. [Nuclear Research Institute Rez plc (Czech Republic); Sus, F. [Research Centre Rez Ltd. (Czech Republic); Nuclear Research Institute Rez plc (Czech Republic); Kucera, J. [Research Centre Rez Ltd. (Czech Republic); Nuclear Physics Institute, Academy of Sciences of the Czech Republic (Czech Republic); Kus, P.; Marek, M. [Research Centre Rez Ltd. (Czech Republic); Nuclear Research Institute Rez plc (Czech Republic)

    2011-03-11

    We have designed a new type of detectors, called transmutation detectors, which can be used primarily for neutron fluence measurement. The transmutation detector method differs from the commonly used activation detector method in evaluation of detector response after irradiation. Instead of radionuclide activity measurement using radiometric methods, the concentration of stable non-gaseous nuclides generated by transmutation in the detector is measured using analytical methods like mass spectrometry. Prospective elements and nuclear reactions for transmutation detectors are listed and initial experimental results are given. The transmutation detector method could be used primarily for long-term measurement of neutron fluence in fission nuclear reactors, but in principle it could be used for any type of radiation that can cause transmutation of nuclides in detectors. This method could also be used for measurement in accelerators or fusion reactors.

  2. Transmutation detectors

    International Nuclear Information System (INIS)

    Viererbl, L.; Lahodova, Z.; Klupak, V.; Sus, F.; Kucera, J.; Kus, P.; Marek, M.

    2011-01-01

    We have designed a new type of detectors, called transmutation detectors, which can be used primarily for neutron fluence measurement. The transmutation detector method differs from the commonly used activation detector method in evaluation of detector response after irradiation. Instead of radionuclide activity measurement using radiometric methods, the concentration of stable non-gaseous nuclides generated by transmutation in the detector is measured using analytical methods like mass spectrometry. Prospective elements and nuclear reactions for transmutation detectors are listed and initial experimental results are given. The transmutation detector method could be used primarily for long-term measurement of neutron fluence in fission nuclear reactors, but in principle it could be used for any type of radiation that can cause transmutation of nuclides in detectors. This method could also be used for measurement in accelerators or fusion reactors.

  3. Developing and evaluating new micropattern gas detectors

    International Nuclear Information System (INIS)

    Villa, Marco

    2014-02-01

    Micropattern gas detectors (MPGDs) were introduced in the late 1980s in order to overcome the limited rate capability of traditional proportional counters. Thanks to their microscopic electrode structures, MPGDs are faster and more precise than the previous gas detectors and soon gained popularity. Two of the most successful MPGDs are the gas electron multiplier (GEM) and the micro-mesh gaseous structure (Micromegas). In this thesis I present the features of GEMs and Micromegas, some of their current applications and the research and development that I have done on these technologies. My activity covered two main topics: the test and enhancement of single-mask GEMs for large-area applications and the study of spark-tolerant Micromegas for the upgrade of the ATLAS Small Wheels.

  4. Evaluation of the Field Gradient Lattice Detector

    CERN Document Server

    AUTHOR|(CDS)2072983

    A novel Micro Pattern Gas Detector, named the Field Gradient Lattice Detector, has been implemented using technologies available to CERN’s Printed Circuit Workshop. Numerous prototypes based on various materials were constructed in different geometries and their gain performance has been studied using 55Fe and 109Cd X-ray sources in Argon-CO2 gas mixtures. Two axis (2D) prototype structures have been shown to provide stable gains of around 1000 while a 3D design, based on the same polyimide foils used in other MPGD elements, holds a gain of 5000 for 8.9 keV X-rays even at high rates of 22 kHz/mm2. At a gain of 3100, the device has been tested up to 1 MHz/mm2 and shows no signs of degradation in performance. The energy resolution of the 3D-in-polyimide is modest, around 40% for 5.9 keV X-rays and 30% if the source is collimated indicating a variation in gain over the 3x3 cm2 active area. Having the most promise for future applications, the 3D-in-polyimide design has been selected for testing with a custom-bu...

  5. Gravitational Waves from Known Pulsars: Results from the Initial Detector Era

    NARCIS (Netherlands)

    Aasi, J.; et al., [Unknown; Hessels, J.W.T.

    2014-01-01

    We present the results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and

  6. A Nuisance Alarm Data System for evaluation of intrusion detectors

    International Nuclear Information System (INIS)

    Ream, W.K.

    1990-01-01

    A Nuisance Alarm Data System (NADS) was developed to gather long-term background alarm data on exterior intrusion detectors as part of their evaluation. Since nuisance alarms play an important part in the selection of intrusion detectors for use at Department of Energy (DOE) facilities, an economical and reliable way to monitor and record these alarms was needed. NADS consists of an IBM personal computer and printer along with other commercial units to communicate with the detectors, to gather weather data, and to record video for assessment. Each alarm, its assessment, and the weather conditions occurring at alarm time are placed into a data base that is used in the evaluation of the detector. The operating software is written in Turbo Pascal for easy maintenance and modification. A portable system, based on the NADS design, has been built and shipped to other DOE locations to do on-site alarm monitoring. This has been valuable for the comparison of different detectors in the on-site environment and for testing new detectors when the appropriate conditions do not exist or cannot be simulated at the Exterior Intrusion Detection Testbed

  7. Myocardial perfusion with multi-detector computed tomography: quantitative evaluation

    International Nuclear Information System (INIS)

    Carrascosa, Patricia M.; Vallejos, J.; Capunay, Carlos M.; Deviggiano, A.; Carrascosa, Jorge M.

    2007-01-01

    The objective of this work is to evaluate the skill of multidetector computer tomography, to quantify the different patterns of intensification during the evaluation of the myocardial perfusion. 45 patients were studied with suspicion of cardiovascular disease. Multi-detector computed tomography was utilized on patients at rest and in effort with pharmacological stress, after the administration of dipyridamole. Also they were evaluated using nuclear medicine [es

  8. Detector design and evaluation for the solenoidal tracker at RHIC

    International Nuclear Information System (INIS)

    Howe, H.; Ahmad, S.; Bonner, B.E.

    1992-01-01

    There are two components to this research, both at the high-η ends of the STAR detector to be built in Brookhaven in 1997. The first project is to design the start counters to be placed along the incident beam-pipe. These detectors will be used to determine the starting time for the TOF layer, which, in conjunction with the main low-η TPC detectors, will determine particle identification. The TOF system will need a time resolution of 100 ps, which must be reflected in the start counter design. The start counter will detect particles emitted with pseudorapidities of η-4.5-5.5, and the size of the counter is dependent on the placement of the counter along the beam pipe. The authors will also explore start counter segmentation and light collection from the scintillator. Second, they are using computer simulation to try to calculate the initial momentum of particles, given their crossing points through the high-η TPCs. A computer model can give one such track through the TPCs. By modelling the track of the particle back through an ideal magnetic field, the authors can estimate the initial momentum. Then, based on this momentum, they project the particle through a complex magnetic field corresponding to the actual field generated and determine where that particle strikes the TPCs. By then varying the initial momentum slightly, they can minimize the difference between such tracks and the original track and, thus, accurately calculate the initial momentum

  9. Evaluation of high performance data acquisition boards for simultaneous sampling of fast signals from PET detectors

    International Nuclear Information System (INIS)

    Judenhofer, Martin S; Pichler, Bernd J; Cherry, Simon R

    2005-01-01

    Detectors used for positron emission tomography (PET) provide fast, randomly distributed signals that need to be digitized for further processing. One possibility is to sample the signals at the peak initiated by a trigger from a constant fraction discriminator (CFD). For PET detectors, simultaneous acquisition of many channels is often important. To develop and evaluate novel PET detectors, a flexible, relatively low cost and high performance laboratory data acquisition (DAQ) system is therefore required. The use of dedicated DAQ systems, such as a multi-channel analysers (MCAs) or continuous sampling boards at high rates, is expensive. This work evaluates the suitability of well-priced peripheral component interconnect (PCI)-based 8-channel DAQ boards (PD2-MFS-8 2M/14 and PD2-MFS-8-500k/14, United Electronic Industries Inc., Canton, MA, USA) for signal acquisition from novel PET detectors. A software package was developed to access the board, measure basic board parameters, and to acquire, visualize, and analyse energy spectra and position profiles from block detectors. The performance tests showed that the boards input linearity is >99.2% and the standard deviation is 22 Na source was 14.9% (FWHM) at 511 keV and is slightly better than the result obtained with a high-end single channel MCA (8000A, Amptek, USA) using the same detector (16.8%). The crystals (1.2 x 1.2 x 12 mm 3 ) within a 9 x 9 LSO block detector could be clearly separated in an acquired position profile. Thus, these boards are well suited for data acquisition with novel detectors developed for nuclear imaging

  10. Performance evaluation of PFBR wire type sodium leak detectors

    International Nuclear Information System (INIS)

    Vijayakumar, G.; Rajan, K.K.; Nashine, B.K.; Chandramouli, S.; Madhusoodanan, K.; Kalyanasundaram, P.

    2011-01-01

    Highlights: → Performance evaluation of wire type leak detectors was conducted in LEENA facility by creating sodium leaks. → The lowest leak rate of 214 g/h was detected in 50 min and the highest detection time was 6 h for a leak rate of 222 g/h. → Factors affecting the leak detection time are packing density of thermal insulation, layout of heater, temperature, etc. → Relationship between leak rate and detection time was established and a leak rate of 100 g/h is likely to be detected in 11.1 h. → Contact resistance of leaked sodium increased to 3.5 kilo ohms in 20 h. - Abstract: Wire type leak detectors working on conductivity principle are used for detecting sodium leak in the secondary sodium circuits of fast breeder reactors. It is required to assess the performance of these detectors and confirm that they are meeting the requirements. A test facility by name LEENA was constructed at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam to test the wire type leak detector lay out by simulating different sodium leak rates. This test facility consists of a sodium dump tank, a test vessel, interconnecting pipelines with valves, micro filter and test section with leak simulators. There are three different test sections in the test set up of length 1000 mm each. These test sections simulate piping of Prototype Fast Breeder Reactor (PFBR) secondary circuit and the wire type leak detector layout in full scale. All test sections are provided with leak simulators. A leak simulator consists of a hole of size one mm drilled in the test section and closed with a tapered pin. The tapered pin position in the hole is adjusted by a screw mechanism and there by the annular gap of flow area is varied for getting different leak rates. Various experiments were conducted to evaluate the performance of the leak detectors by creating different sodium leak rates. This paper deals with the details of wire type leak detector layout for the secondary sodium circuit of

  11. Initial Evaluation of Patients with Presumed Syncope

    Directory of Open Access Journals (Sweden)

    Ilknur Can, MD

    2008-01-01

    Full Text Available Syncope is a common clinical problem, but nevertheless is but one element of the broader issue of ‘transient loss of consciousness’ (TLOC. The first step is to ascertain whether the patient actually suffered a syncopal episode, and thereafter the goal must be to determine the basis of symptoms with sufficient confidence to assess prognosis and initiate an effective treatment strategy. The initial evaluation of these patients, which usually takes place in an emergency department (ED. or acute care facility, is challenging since patients are usually asymptomatic when they come for medical attention, may have little or no recall of the event, and witnesses, if any, often cannot provide reliable information. Given these circumstances, it is understandable that frontline physicians often tend to take a seemingly ‘safe’ approach, and admit both high-risk and intermediate-risk syncope patients to hospital. This strategy has many implications, including life-style and economic concerns for the patient, and health care management issues for physicians, hospital administrators and the overall health care system. The European Society of Cardiology (ESC. guidelines and several clinical studies provide helpful advice regarding “risk stratification” to help guide physicians in selecting patients for either early hospital admission or later oupatient subspeciality evaluation. The utility of syncope management units in the ED, and a guideline-based approach to the syncope patient, has tended to both diminish the number of undiagnosed cases and reduce the hospital admission rate. In this review, we have attempted to both highlight a cost-effective diagnostic pathway beginning with the initial evaluation of the patient with suspected syncope, and to provide criteria which may help frontline physicians better base their decisions regarding need for in-hospital versus outpatient clinic evaluation of syncope patients.

  12. Dose evaluation from multiple detector outputs using convex optimisation

    International Nuclear Information System (INIS)

    Hashimoto, M.; Iimoto, T.; Kosako, T.

    2011-01-01

    A dose evaluation using multiple radiation detectors can be improved by the convex optimisation method. It enables flexible dose evaluation corresponding to the actual radiation energy spectrum. An application to the neutron ambient dose equivalent evaluation is investigated using a mixed-gas proportional counter. The convex derives the certain neutron ambient dose with certain width corresponding to the true neutron energy spectrum. The range of the evaluated dose is comparable to the error of conventional neutron dose measurement equipments. An application to the neutron individual dose equivalent measurement is also investigated. Convexes of particular dosemeter combinations evaluate the individual dose equivalent better than the dose evaluation of a single dosemeter. The combinations of dosemeters with high orthogonality of their response characteristics tend to provide a good suitability for dose evaluation. (authors)

  13. Evaluation of a flat-panel detector system

    International Nuclear Information System (INIS)

    Sato, Masami; Eguchi, Yoichi; Yamada, Kinichi; Kaga, Yuji; Endo, Yutaka; Yamazaki, Tatsuya

    2001-01-01

    We evaluated the imaging performance of a flat-panel detector digital radiography system (CXDI-11 X-ray Digital Camera, Canon Inc.) and a computed radiography system (FCR9000C-HQ, Fuji Film). The characteristics of the two detectors and of the overall systems were compared. This included evaluation and comparison of the fundamental physical characteristics, including x-ray response curve, modulation transfer function (MTF), Wiener spectra, noise-equivalent quanta, and x-ray tube voltage-dependent detector response. Overall system performance was evaluated using receiver operating characteristic (ROC) analysis. The results of the study showed that the dynamic range of the CXDI-11 measured relative to the input x-ray flux was 10 3 , similar to that of the FCR9000C-HQ. Both systems showed similar final MTFs, although the pre-sampling MTF of the CXDI-11 was better than that of the FCR9000C-HQ. Noise analysis, based on noise-equivalent quanta and Wiener spectra, showed that for normal exposure conditions the CXDI-11 had superior performance. With both systems, x-ray response (system output/incident x-ray exposure) increased with increasing x-ray tube voltage. ROC analysis indicated that the CXDI-11 was superior in overall performance. (author)

  14. Initial characterization of a BGO-photodiode detector for high resolution positron emission tomography

    International Nuclear Information System (INIS)

    Derenzo, S.E.

    1983-11-01

    Spatial resolution in positron emission tomography is currently limited by the resolution of the detectors. This work presents the initial characterization of a detector design using small bismuth germanate (BGO) crystals individually coupled to silicon photodiodes (SPDs) for crystal identification, and coupled in groups to phototubes (PMTs) for coincidence timing. A 3 mm x 3 mm x 3 mm BGO crystal coupled only to an SPD can achieve a 511 keV photopeak resolution of 8.7% FWHM at -150 0 C, using a pulse peaking time of 10 μs. When two 3 mm x 3 mm x 15 mm BGO crystals are coupled individually to SPDs and also coupled to a common 14 mm diam PMT, the SPDs detect the 511 keV photopeak with a resolution of 30% FWHM at -76 0 C. In coincidence with an opposing 3 mm wide BGO crystal, the SPDs are able to identify the crystal of interaction with good signal-to-noise ratio, and the detector pair resolution is 2 mm FWHM. 32 references, 7 figures, 3 tables

  15. International intercomparison of neutron spectra evaluating methods using activation detectors

    International Nuclear Information System (INIS)

    Fischer, A.

    1975-06-01

    The international intercomparison of neutron spectrum evaluation methods using activation detectors was organized by the IAEA in 1971 - 1972. All of the contributions and the results of a critical evaluation are presented here. The spectra of different contributors are compared to a reference spectrum by means of different integrals and weighting functions. Different cross section sets, foil numbers, energy point systems, guess spectra used by the contributors cause differences in the resulting spectra. The possible ways of separating these effects are also investigated. Suggestions are made for the organization of a new intercomparison on the basis of more uniform input data. (orig.) [de

  16. Fano factor evaluation of diamond detectors for alpha particles

    Energy Technology Data Exchange (ETDEWEB)

    Shimaoka, Takehiro; Kaneko, Junichi H.; Tsubota, Masakatsu; Shimmyo, Hiroaki [Graduate School of Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo, Hokkaido, 060-8628 (Japan); Sato, Yuki [Naraha Remote Technology Development Center, Japan Atomic Energy Agency, Naraha-machi, Futaba-gun, Fukushima, 979-0513 (Japan); Chayahara, Akiyoshi; Umezawa, Hitoshi; Mokuno, Yoshiaki [Advanced Power Electronics Research Center, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka, 563-8577 (Japan); Watanabe, Hideyuki [Research Institute for Electronics and Photonics, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, 305-8565 (Japan)

    2016-10-15

    This report is the first describing experimental evaluation of Fano factor for diamond detectors. High-quality self-standing chemical vapor deposited diamond samples were produced using lift-off method. Alpha-particle induced charge measurements were taken for three samples. A 13.1 ±0.07 eV of the average electron-hole pair creation energy and excellent energy resolution of approximately 0.3% were found for 5.486 MeV alpha particles from an {sup 241}Am radioactive source. The best Fano factor for 5.486 MeV alpha particles, calculated from experimentally obtained epsilon values and the detector intrinsic energy resolution, was 0.382 ± 0.007. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Investigation about semiconductor gamma ray detector - Evaluation of Ge(Li) detectors life expectation

    International Nuclear Information System (INIS)

    1980-06-01

    A list of germanium lithium gamma ray detectors has been drawn up by a working group after investigations in various laboratories. Authors analyse the historical account of each detector and try to give an answer about some questions as: - detectors life expectation, - deficiencies and death reasons, - influence of detector type and volume. Differents parameters are also collected by the working group for future works (standard geometry, low level measurements, etc.). In the list, the characteristics of 228 detectors, collected between january 1965 and december 1977 are put together. The principal conclusions of the authors are: - with a probability of 95%, half of the detectors is dead before 6.1 years, - the average age of dead population (33% of detectors) is 3.9 years, - resolution and efficiency evolution are good indicators of possible deficiency, - the fiability of vertical cryostat is better than the other systems [fr

  18. Software Dependability and Safety Evaluations ESA's Initiative

    Science.gov (United States)

    Hernek, M.

    ESA has allocated funds for an initiative to evaluate Dependability and Safety methods of Software. The objectives of this initiative are; · More extensive validation of Safety and Dependability techniques for Software · Provide valuable results to improve the quality of the Software thus promoting the application of Dependability and Safety methods and techniques. ESA space systems are being developed according to defined PA requirement specifications. These requirements may be implemented through various design concepts, e.g. redundancy, diversity etc. varying from project to project. Analysis methods (FMECA. FTA, HA, etc) are frequently used during requirements analysis and design activities to assure the correct implementation of system PA requirements. The criticality level of failures, functions and systems is determined and by doing that the critical sub-systems are identified, on which dependability and safety techniques are to be applied during development. Proper performance of the software development requires the development of a technical specification for the products at the beginning of the life cycle. Such technical specification comprises both functional and non-functional requirements. These non-functional requirements address characteristics of the product such as quality, dependability, safety and maintainability. Software in space systems is more and more used in critical functions. Also the trend towards more frequent use of COTS and reusable components pose new difficulties in terms of assuring reliable and safe systems. Because of this, its dependability and safety must be carefully analysed. ESA identified and documented techniques, methods and procedures to ensure that software dependability and safety requirements are specified and taken into account during the design and development of a software system and to verify/validate that the implemented software systems comply with these requirements [R1].

  19. Systematic evaluation program. Status report and initial evaluation

    International Nuclear Information System (INIS)

    1983-06-01

    The MHB Ongoing Systematic Evaluation Program (SEP) Assessment Study was initiated by the Swedish Nuclear Power Inspectorate (SKI) in 1980. This MHB report is a status report and initial evaluation of SEP. The methodology and results of SEP are disscused with particular emphasis on the first two SEP plant reviews - the Palisades and R.E. Ginna nuclear power plants. The comments of cognizant persons in the NRC and the ACRS, as well as private consultants, are included herein. MHBs major findings are as follows: The SEP plant review methodology was acceptable to the NRC Commissioners, the ACRS, and the NRC Staffs consultants who evaluated the first two SEP plant reviews. A concern raised by all who commented on SEP was the absence of Three Mile Island Action Plan Items and Unresolved Safety Issues from current SEP reviews. The SEP reviews of the Palisades and R.E. Ginna plants concluded that the two plant designs were adequate with respect to a majority of safety topics. Several topics remain unresolved in both the Palisades and R.E. Ginna SEP reviews. In the case of the Ginna plant, several related topics have been grouped together in a major structural reevaluation study. In general, due to the number of unresolved and excluded topics, SEP has not at this time produced a plant safety evaluation which can be considered complete and integrated. (author)

  20. Personal Radiation Detector Field Test and Evaluation Campaign

    International Nuclear Information System (INIS)

    Chris A. Hodge, Ding Yuan, Raymond P. Keegan, Michael A. Krstich

    2007-01-01

    Following the success of the Anole test of portable detection system, the U.S. Department of Homeland Security (DHS) Domestic Nuclear Detection Office organized a test and evaluation campaign for personal radiation detectors (PRDs), also known as 'Pagers'. This test, 'Bobcat', was conducted from July 17 to August 8, 2006, at the Nevada Test Site. The Bobcat test was designed to evaluate the performance of PRDs under various operational scenarios, such as pedestrian surveying, mobile surveying, cargo container screening, and pedestrian chokepoint monitoring. Under these testing scenarios, many operational characteristics of the PRDs, such as gamma and neutron sensitivities, positive detection and false alarm rates, response delay times, minimum detectable activities, and source localization errors, were analyzed. This paper will present the design, execution, and methodologies used to test this equipment for the DHS

  1. Automated electronic intruder simulator for evaluation of ultrasonic intrusion detectors

    International Nuclear Information System (INIS)

    1979-01-01

    An automated electronic intruder simulator for testing ultrasonic intrusion detectors is described. This simulator is primarily intended for use in environmental chambers to determine the effects of temperature and humidity on the operation of ultrasonic intrusion detectors

  2. Evaluation of digital detector arrays systems for industrial radiography

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Aline S.S.; Oliveira, Davi F.; Gomes, Célio S.; Azeredo, Soraia R.; Lopes, Ricardo T., E-mail: aline@lin.ufrj.br, E-mail: davi@lin.ufrj.br.br, E-mail: celio@lin.ufrj.br, E-mail: soraia@lin.ufrj.br, E-mail: ricardo@lin.ufrj.br, E-mail: davi.oliveira@uerj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Instrumentação Nuclear

    2017-07-01

    Digital Detector Arrays (DDA) or Flat Panel Detector (FPD) is a highly efficient technique that is used in nondestructive testing of internal features of an object. The evaluation of DDA systems for industrial radiography is important to ensure the image quality and to enables long-term stability of this system. This evaluation is specified by ASTM E2737 - 10, which describes the fundamental parameters of DDA systems to be measured. The tests require the usage of either the five-groove wedge or the duplex plate phantom with separate Image Quality Indicators (IQIs). The purpose of this work was evaluate the radiographic performance achieved using both techniques in two DDA systems manufactured by GEIT: DXR250P and DXR250V, which have thallium-doped cesium iodide (CsI:Tl) and terbium-doped gadolinium oxysulfide (Gd{sub 2}O{sub 2}S:Tb - GOS) scintillators, respectively. For this purpose, it was used an X-ray equipment as radiation source. The image quality parameters analyzed were Image Lag (IL), Offset Level (OL), Bad Pixel distribution, Burn In (BI), Spatial Resolution (SR), Material Thickness Range (MTR), Contrast Sensitivity (CS), Signal Level (SL) and Signal-to-Noise Ratio (SNR). As result of this study, has been observed that the use of the five-groove wedge phantom made the measurements to become easier to execute. Regarding the DDA system, the DXR250P presented more IL and BI, but produced images with better CS and SNR and needed a dose almost twice smaller than the DXR250V to achieve a similar SL. (author)

  3. Evaluation of digital detector arrays systems for industrial radiography

    International Nuclear Information System (INIS)

    Silva, Aline S.S.; Oliveira, Davi F.; Gomes, Célio S.; Azeredo, Soraia R.; Lopes, Ricardo T.

    2017-01-01

    Digital Detector Arrays (DDA) or Flat Panel Detector (FPD) is a highly efficient technique that is used in nondestructive testing of internal features of an object. The evaluation of DDA systems for industrial radiography is important to ensure the image quality and to enables long-term stability of this system. This evaluation is specified by ASTM E2737 - 10, which describes the fundamental parameters of DDA systems to be measured. The tests require the usage of either the five-groove wedge or the duplex plate phantom with separate Image Quality Indicators (IQIs). The purpose of this work was evaluate the radiographic performance achieved using both techniques in two DDA systems manufactured by GEIT: DXR250P and DXR250V, which have thallium-doped cesium iodide (CsI:Tl) and terbium-doped gadolinium oxysulfide (Gd 2 O 2 S:Tb - GOS) scintillators, respectively. For this purpose, it was used an X-ray equipment as radiation source. The image quality parameters analyzed were Image Lag (IL), Offset Level (OL), Bad Pixel distribution, Burn In (BI), Spatial Resolution (SR), Material Thickness Range (MTR), Contrast Sensitivity (CS), Signal Level (SL) and Signal-to-Noise Ratio (SNR). As result of this study, has been observed that the use of the five-groove wedge phantom made the measurements to become easier to execute. Regarding the DDA system, the DXR250P presented more IL and BI, but produced images with better CS and SNR and needed a dose almost twice smaller than the DXR250V to achieve a similar SL. (author)

  4. Evaluation of hand-held ion-mobility explosives vapor detectors

    International Nuclear Information System (INIS)

    Burrows, T.A.; Thoma, P.J.

    1979-12-01

    Two types of ion-mobility detectors were evaluated in both laboratory and field tests. Laboratory test results show that these detectors are highly sensitive to dynamite and pistol powder and have good false-alarm agent rejection. Field tests of these two detectors revealed that they would detect dynamite and Ball-C-Propellent in free air. However, neither of the ion-mobility detectors would detect these explosives if the explosives were concealed

  5. Evaluation of myocardial ischemia by multiple detector computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Fabio Vieira, E-mail: rccury@me.com [Hospital do Coracao (HCor), Sao Paulo, SP (Brazil); Cury, Roberto Caldeira [Hospital Samaritano, Sao Paulo, SP (Brazil)

    2015-01-15

    For years, cardiovascular diseases have been the leading cause of death worldwide, bringing on important social and economic consequences. Given this scenario, the search for a method capable of diagnosing coronary artery diseases in an early and accurate way is increasingly higher. The coronary computed tomography angiogram is already widely established for the stratification of coronary artery diseases, and, more recently, the computed tomography myocardial perfusion imaging has been providing relevant information by correlating ischemia and the coronary anatomy. The objective of this review is to describe the evaluation of myocardial ischemia by multiple detector computed tomography. This study will resort to controlled clinical trials that show the possibility of a single method to identify the atherosclerotic load, presence of coronary artery luminal narrowing and possible myocardial ischemia, by means of a fast, practical and reliable method validated by a multicenter study. (author)

  6. Two gamma dose evaluation methods for silicon semiconductor detector

    International Nuclear Information System (INIS)

    Chen Faguo; Jin Gen; Yang Yapeng; Xu Yuan

    2011-01-01

    Silicon PIN diodes have been widely used as personal and areal dosimeters because of their small volume, simplicity and real-time operation. However, because silicon is neither a tissue-equivalent nor an air-equivalent material, an intrinsic disadvantage for silicon dosimeters is that a significant over-response occurs at low-energy region, especially below 200 keV. Using a energy compensation filter to flatten the energy response is one method overcoming this disadvantage. But for dose compensation method, the estimated dose depends only on the number of the detector pulses. So a weight function method was introduced to evaluate gamma dose, which depends on pulse number as well as its amplitude. (authors)

  7. Fabrication of advanced military radiation detector sensor and performance evaluation

    International Nuclear Information System (INIS)

    Kang, Sin Yang

    2010-02-01

    Recently, our country is facing a continuous nuclear weapons threat. Therefore, we must have a high-level nuclear weapons protection system. The best protection against nuclear weapons is detecting their use to reduce casualties in our country to a minimum. That means, the development of a military radiation detector is a very important issue. The Korea army is using the 'PDR - 1K portable military radiation surveymeter' in NBC (Nuclear, Biological, Chemical warfare) operations. The PDR - 1K military detector can measure beta and gamma rays only but it cannot detect alpha particles. Because of its characteristics, the Korea army has weaknesses in tactical operations. The PDR - 1K sensor is based on a GM - tube sensor system. For the mechanical structure, detectors utilizing a GM-tube sensor do not work on a high - radiation battlefield and they do not carry out nuclide analysis for fixed electron signal output. In the meantime, the United States of America and Germany are using 'AN/PDR - 77' and 'SVG - 2' that were made from scintillator sensors. They have excellent physical qualities and radiation responses for military use. Also, nuclide analysis is available. Therefore, in this study we fabricated a military - grade scintillator radiation sensor that is able to detect alpha, beta, and gamma - rays to overcome PDR - 1K's weaknesses. Also, physical characteristics and radiation response evaluation for the fabricated sensors was carried out. The alpha - particle sensor and beta - ray sensor were fabricated using a ZnS(Ag) powder state scintillator, and a Saint - Gobain organic plastic scintillator BC-408 panel, respectively. The gamma ray sensor was manufactured using a 10 x 10 x 10 mm 3 CsI(Tl) inorganic scintillator crystal. A detailed explanation follows. The alpha particle sensor was fabricated by using air - brushing method to Zns(Ag) powder scintillator spreading. The ZnS(Ag) layer thickness was 35 μm (detection efficiency: 41%). This alpha - particle sensor

  8. Evaluation of Irradiated Barrel Detector Modules for the Upgrade of the CMS Pixel Detector

    CERN Document Server

    Sibille, Jennifer Ann

    2013-01-01

    Prototype detector modules comprising sensors and the new readout chips were assembled and irradiated with protons at the CERN PS, and readout chips without sensors have been irradiated with protons at the Karls...

  9. Evaluation of the detector response function digital conventional radiology

    International Nuclear Information System (INIS)

    Arino Gil, A.; Hernandez Rodriguez, J.; Mateos Salvador, P.; Rodriguez Lopez, B.; Font Gelabert, J. C.

    2013-01-01

    The objective of this work is to obtain the response function that relates the air kerma at the entrance of the detector and pixel value, for a series of digital detectors of conventional Radiology model Optimus DigitalDiagnost Philips () and 6000 Definium General Electric. From the set of measurements is obtained a response function for each reference type of detector, and compared with those published in the literature for these teams. (Author)

  10. Initial results from 3D-DDTC detectors on p-type substrates

    Energy Technology Data Exchange (ETDEWEB)

    Zoboli, A., E-mail: zoboli@disi.unitn.i [Dipartimento di Ingegneria e Scienza dell' Informazione, Universita di Trento, and INFN, Sezione di Padova (Gruppo Collegato di Trento), Via Sommarive, 14, I-38100 Povo di Trento (Italy); Boscardin, M. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi, Via Sommarive, 18, I-38100 Povo di Trento (Italy); Bosisio, L. [Dipartimento di Fisica, Universita di Trieste, and INFN, Sezione di Trieste, Via A. Valerio, 2, I-34127 Trieste (Italy); Dalla Betta, G.-F. [Dipartimento di Ingegneria e Scienza dell' Informazione, Universita di Trento, and INFN, Sezione di Padova (Gruppo Collegato di Trento), Via Sommarive, 14, I-38100 Povo di Trento (Italy); Piemonte, C.; Ronchin, S.; Zorzi, N. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi, Via Sommarive, 18, I-38100 Povo di Trento (Italy)

    2010-01-11

    Owing to their superior radiation hardness compared to planar detectors, 3D detectors are one of the most promising technologies for the LHC upgrade foreseen in 2017. Fondazione Bruno Kessler has developed 3D Double-side Double-Type Column (3D-DDTC) detectors providing a technological simplifications with respect to a standard 3D process while aiming at comparable detector performance. We present selected results from the electrical characterization of 3D-DDTC structures from the second batch made on p-type substrates, supported also by TCAD simulations.

  11. Practical recommendations for the evaluation of improvement initiatives

    Science.gov (United States)

    Parry, Gareth; Coly, Astou; Goldmann, Don; Rowe, Alexander K; Chattu, Vijay; Logiudice, Deneil; Rabrenovic, Mihajlo; Nambiar, Bejoy

    2018-01-01

    Abstract A lack of clear guidance for funders, evaluators and improvers on what to include in evaluation proposals can lead to evaluation designs that do not answer the questions stakeholders want to know. These evaluation designs may not match the iterative nature of improvement and may be imposed onto an initiative in a way that is impractical from the perspective of improvers and the communities with whom they work. Consequently, the results of evaluations are often controversial, and attribution remains poorly understood. Improvement initiatives are iterative, adaptive and context-specific. Evaluation approaches and designs must align with these features, specifically in their ability to consider complexity, to evolve as the initiative adapts over time and to understand the interaction with local context. Improvement initiatives often identify broadly defined change concepts and provide tools for care teams to tailor these in more detail to local conditions. Correspondingly, recommendations for evaluation are best provided as broad guidance, to be tailored to the specifics of the initiative. In this paper, we provide practical guidance and recommendations that funders and evaluators can use when developing an evaluation plan for improvement initiatives that seeks to: identify the questions stakeholders want to address; develop the initial program theory of the initiative; identify high-priority areas to measure progress over time; describe the context the initiative will be applied within; and identify experimental or observational designs that will address attribution. PMID:29447410

  12. Coronary computed tomography angiography with 320-row detector and using the AIDR-3D: initial experience

    International Nuclear Information System (INIS)

    Sasdelli Neto, Roberto; Nomura, Cesar Higa; Macedo, Ana Carolina Sandoval; Bianco, Danilo Perussi; Kay, Fernando Uliana; Szarf, Gilberto; Teles, Gustavo Borges da Silva; Shoji, Hamilton; Santana Netto, Pedro Vieira; Passos, Rodrigo Bastos Duarte; Chate, Rodrigo Caruso; Ishikawa, Walther Yoshiharu; Lima, Joao Paulo Bacellar Costa; Rocha, Marcelo Assis; Marcos, Vinicius Neves; Funari, Marcelo Buarque de Gusmao; Failla, Bruna Bonaventura

    2013-01-01

    Coronary computed tomography angiography (coronary CTA) is a powerful non-invasive imaging method to evaluate coronary artery disease. Nowadays, coronary CTA estimated effective radiation dose can be dramatically reduced using state-of-the-art scanners, such as 320-row detector CT (320-CT), without changing coronary CTA diagnostic accuracy. To optimize and further reduce the radiation dose, new iterative reconstruction algorithms were released recently by several CT manufacturers, and now they are used routinely in coronary CTA. This paper presents our first experience using coronary CTA with 320-CT and the Adaptive Iterative Dose Reduction 3D (AIDR-3D). In addition, we describe the current indications for coronary CTA in our practice as well as the acquisition standard protocols and protocols related to CT application for radiation dose reduction. In conclusion, coronary CTA radiation dose can be dramatically reduced following the 'as low as reasonable achievable' principle by combination of exam indication and well-documented technics for radiation dose reduction, such as beta blockers, low-kV, and also the newest iterative dose reduction software as AIDR-3D. (author)

  13. Scan equalization digital radiography (SEDR) implemented with an amorphous selenium flat-panel detector: initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xinming; Lai Chaojen; Chen Lingyun; Han Tao; Zhong Yuncheng; Shen Youtao; Wang Tianpeng; Shaw, Chris C [Department of Imaging Physics, Digital Imaging Research Laboratory, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030-4009 (United States)], E-mail: xliu@di.mdacc.tmc.edu

    2009-11-21

    It is well recognized in projection radiography that low-contrast detectability suffers in heavily attenuating regions due to excessively low x-ray fluence to the image receptor and higher noise levels. Exposure equalization can improve image quality by increasing the x-ray exposure to heavily attenuating regions, resulting in a more uniform distribution of exposure to the detector. Image quality is also expected to be improved by using the slot-scan geometry to reject scattered radiation effectively without degrading primary x-rays. This paper describes the design of a prototype scan equalization digital radiography (SEDR) system implemented with an amorphous silicon (a-Si) thin-film transistor (TFT) array-based flat-panel detector. With this system, slot-scan geometry with alternate line erasure and readout (ALER) technique was used to achieve scatter rejection. A seven-segment beam height modulator assembly was mounted onto the fore collimator to regulate exposure regionally for chest radiography. The beam modulator assembly, consisting of micro linear motors, lead screw cartridge with lead (Pb) beam blockers attached, position feedback sensors and motor driver circuitry, has been tested and found to have an acceptable response for exposure equalization in chest radiography. An anthropomorphic chest phantom was imaged in the posterior-anterior (PA) view under clinical conditions. Scatter component, primary x-rays, scatter-to-primary ratios (SPRs) and primary signal-to-noise ratios (PSNRs) were measured in the SEDR images to evaluate the rejection and redistribution of scattered radiation, and compared with those for conventional full-field imaging with and without anti-scatter grid methods. SPR reduction ratios (SPRRRs, defined as the differences between the non-grid full-field SPRs and the reduced SPRs divided by the former) yielded approximately 59% for the full-field imaging with grid and 82% for the SEDR technique in the lungs, and 77% for the full

  14. Fabrication of advanced military radiation detector sensor and performance evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sin Yang

    2010-02-15

    Recently, our country is facing a continuous nuclear weapons threat. Therefore, we must have a high-level nuclear weapons protection system. The best protection against nuclear weapons is detecting their use to reduce casualties in our country to a minimum. That means, the development of a military radiation detector is a very important issue. The Korea army is using the 'PDR - 1K portable military radiation surveymeter' in NBC (Nuclear, Biological, Chemical warfare) operations. The PDR - 1K military detector can measure beta and gamma rays only but it cannot detect alpha particles. Because of its characteristics, the Korea army has weaknesses in tactical operations. The PDR - 1K sensor is based on a GM - tube sensor system. For the mechanical structure, detectors utilizing a GM-tube sensor do not work on a high - radiation battlefield and they do not carry out nuclide analysis for fixed electron signal output. In the meantime, the United States of America and Germany are using 'AN/PDR - 77' and 'SVG - 2' that were made from scintillator sensors. They have excellent physical qualities and radiation responses for military use. Also, nuclide analysis is available. Therefore, in this study we fabricated a military - grade scintillator radiation sensor that is able to detect alpha, beta, and gamma - rays to overcome PDR - 1K's weaknesses. Also, physical characteristics and radiation response evaluation for the fabricated sensors was carried out. The alpha - particle sensor and beta - ray sensor were fabricated using a ZnS(Ag) powder state scintillator, and a Saint - Gobain organic plastic scintillator BC-408 panel, respectively. The gamma ray sensor was manufactured using a 10 x 10 x 10 mm{sup 3} CsI(Tl) inorganic scintillator crystal. A detailed explanation follows. The alpha particle sensor was fabricated by using air - brushing method to Zns(Ag) powder scintillator spreading. The ZnS(Ag) layer thickness was 35 {mu}m (detection

  15. Evaluation of a reflective coating for an organic scintillation detector

    International Nuclear Information System (INIS)

    Tarancón, A.; Marin, E.; Tent, J.; Rauret, G.; Garcia, J.F.

    2012-01-01

    A reflective coating based on white paint, black paint and varnish has been evaluated to determine its reflective capabilities and its potential use in radioactivity detectors based on organic scintillators. Three different white paints, all of which were based on TiO 2 , were also tested to determine the one with the best performance and lowest radioactivity content. In a first experiment, we evaluated the capability of the reflective coating by measuring 90 Sr/ 90 Y with PSm in a polyethylene vial partially painted with EJ510 (Eljen Technology) reflective paint, black paint and varnish. In a second experiment, we compared the performance of the EJ510 to that of other white paints used for artistic purposes (Vallejo and Rembrandt). The results showed that, when a vial was only partially painted with the white paints (keeping a window free of paint to allow photons to exit), the efficiency and spectral distribution of the painted vial was similar to that of a non-painted vial. This behavior showed the efficiency of the reflective coatings. In terms of reflection capabilities, all of the tested paints were equivalent; however, the background was higher for the EJ510 paint. Analyses using high-resolution gamma spectroscopy indicated the presence of natural radionuclides ( 40 K, 226 Ra and 228 Ra) in the EJ510. On the basis of the results (high reflection capabilities and the absence of radioactive impurities) and its lower cost, the Vallejo paint was selected as the white reflective paint. The final structure of the reflective coating was composed of five white paint layers, a black paint (to avoid external light entrance) and a layer of varnish (to protect the paints).

  16. Evaluation of a reflective coating for an organic scintillation detector

    Science.gov (United States)

    Tarancón, A.; Marin, E.; Tent, J.; Rauret, G.; Garcia, J. F.

    2012-05-01

    A reflective coating based on white paint, black paint and varnish has been evaluated to determine its reflective capabilities and its potential use in radioactivity detectors based on organic scintillators. Three different white paints, all of which were based on TiO2, were also tested to determine the one with the best performance and lowest radioactivity content. In a first experiment, we evaluated the capability of the reflective coating by measuring 90Sr/90Y with PSm in a polyethylene vial partially painted with EJ510 (Eljen Technology) reflective paint, black paint and varnish. In a second experiment, we compared the performance of the EJ510 to that of other white paints used for artistic purposes (Vallejo and Rembrandt). The results showed that, when a vial was only partially painted with the white paints (keeping a window free of paint to allow photons to exit), the efficiency and spectral distribution of the painted vial was similar to that of a non-painted vial. This behavior showed the efficiency of the reflective coatings. In terms of reflection capabilities, all of the tested paints were equivalent; however, the background was higher for the EJ510 paint. Analyses using high-resolution gamma spectroscopy indicated the presence of natural radionuclides (40K, 226Ra and 228Ra) in the EJ510. On the basis of the results (high reflection capabilities and the absence of radioactive impurities) and its lower cost, the Vallejo paint was selected as the white reflective paint. The final structure of the reflective coating was composed of five white paint layers, a black paint (to avoid external light entrance) and a layer of varnish (to protect the paints).

  17. Evaluation of a reflective coating for an organic scintillation detector

    Energy Technology Data Exchange (ETDEWEB)

    Tarancon, A., E-mail: alex.tarancon@ub.edu [Department of Analytical Chemistry of the University of Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Marin, E. [Department of Analytical Chemistry of the University of Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Tent, J. [Servei d' analisis isotopics of the University of Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Rauret, G.; Garcia, J.F. [Department of Analytical Chemistry of the University of Barcelona, Diagonal 647, E-08028 Barcelona (Spain)

    2012-05-11

    A reflective coating based on white paint, black paint and varnish has been evaluated to determine its reflective capabilities and its potential use in radioactivity detectors based on organic scintillators. Three different white paints, all of which were based on TiO{sub 2}, were also tested to determine the one with the best performance and lowest radioactivity content. In a first experiment, we evaluated the capability of the reflective coating by measuring {sup 90}Sr/{sup 90}Y with PSm in a polyethylene vial partially painted with EJ510 (Eljen Technology) reflective paint, black paint and varnish. In a second experiment, we compared the performance of the EJ510 to that of other white paints used for artistic purposes (Vallejo and Rembrandt). The results showed that, when a vial was only partially painted with the white paints (keeping a window free of paint to allow photons to exit), the efficiency and spectral distribution of the painted vial was similar to that of a non-painted vial. This behavior showed the efficiency of the reflective coatings. In terms of reflection capabilities, all of the tested paints were equivalent; however, the background was higher for the EJ510 paint. Analyses using high-resolution gamma spectroscopy indicated the presence of natural radionuclides ({sup 40}K, {sup 226}Ra and {sup 228}Ra) in the EJ510. On the basis of the results (high reflection capabilities and the absence of radioactive impurities) and its lower cost, the Vallejo paint was selected as the white reflective paint. The final structure of the reflective coating was composed of five white paint layers, a black paint (to avoid external light entrance) and a layer of varnish (to protect the paints).

  18. Measuring and Analyzing the Scholarly Impact of Experimental Evaluation Initiatives

    DEFF Research Database (Denmark)

    Angelini, Marco; Ferro, Nicola; Larsen, Birger

    2014-01-01

    Evaluation initiatives have been widely credited with contributing highly to the development and advancement of information access systems, by providing a sustainable platform for conducting the very demanding activity of comparable experimental evaluation in a large scale. Measuring the impact...

  19. A novel method for contrast-to-noise ratio (CNR) evaluation of digital mammography detectors

    International Nuclear Information System (INIS)

    Baldelli, P.; Phelan, N.; Egan, G.

    2009-01-01

    The purpose of this study was to test a new, simple method of evaluating the contrast-to-noise ratio (CNR) over the entire image field of a digital detector and to compare different mammography systems. Images were taken under clinical exposure conditions for a range of simulated breast thicknesses using poly(methyl methacrylate) (PMMA). At each PMMA thickness, a second image which included an additional 0.2-mm Al sheet was also acquired. Image processing software was used to calculate the CNR in multiple regions of interest (ROI) covering the entire area of the detector in order to obtain a 'CNR image'. Five detector types were evaluated, two CsI-αSi (GE Healthcare) flat panel systems, one αSe (Hologic) flat panel system and a two generations of scanning photon counting digital detectors (Sectra). Flat panel detectors exhibit better CNR uniformity compared with the first-generation scanning photon counting detector in terms of mean pixel value variation. However, significant improvement in CNR uniformity was observed for the next-generation scanning detector. The method proposed produces a map of the CNR and a measurement of uniformity throughout the entire image field of the detector. The application of this method enables quality control measurement of individual detectors and a comparison of detectors using different technologies. (orig.)

  20. Evaluating the benefits of risk prevention initiatives

    Science.gov (United States)

    Di Baldassarre, G.

    2012-04-01

    The likelihood and adverse impacts of water-related disasters, such as floods and landslides, are increasing in many countries because of changes in climate and land-use. This presentation illustrates some preliminary results of a comprehensive demonstration of the benefits of risk prevention measures, carried out within the European FP7 KULTURisk project. The study is performed by using a variety of case studies characterised by diverse socio-economic contexts, different types of water-related hazards (floods, debris flows and landslides, storm surges) and space-time scales. In particular, the benefits of state-of-the-art prevention initiatives, such as early warning systems, non-structural options (e.g. mapping and planning), risk transfer strategies (e.g. insurance policy), and structural measures, are showed. Lastly, the importance of homogenising criteria to create hazard inventories and build memory, efficient risk communication and warning methods as well as active dialogue with and between public and private stakeholders, is highlighted.

  1. Initial evaluation of the "Trauma surgery course"

    Directory of Open Access Journals (Sweden)

    Tugnoli Gregorio

    2006-03-01

    Full Text Available Abstract Background The consequence of the low rate of penetrating injuries in Europe and the increase in non-operative management of blunt trauma is a decrease in surgeons' confidence in managing traumatic injuries has led to the need for new didactic tools. The aim of this retrospective study was to present the Corso di Chirurgia del Politrauma (Trauma Surgery Course, developed as a model for teaching operative trauma techniques, and assess its efficacy. Method the two-day course consisted of theoretical lectures and practical experience on large-sized swine. Data of the first 126 participants were collected and analyzed. Results All of the 126 general surgeons who had participated in the course judged it to be an efficient model to improve knowledge about the surgical treatment of trauma. Conclusion A two-day course, focusing on trauma surgery, with lectures and life-like operation situations, represents a model for simulated training and can be useful to improve surgeons' confidence in managing trauma patients. Cooperation between organizers of similar initiatives would be beneficial and could lead to standardizing and improving such courses.

  2. Evaluation of detector efficiency through GUPIXWIN H value

    Science.gov (United States)

    Fernandes, F.; Niekraszewicz, L. A. B.; Amaral, L.; Dias, J. F.

    2018-02-01

    In this work we explore the capabilities of the GUPIXWIN software to introduce a simple and straightforward way to obtain the efficiency of X-ray detectors commonly used in PIXE (Particle-Induced X-ray Emission) experiments. To that end, all geometrical parameters of the experimental setup including details of the detector used to detect X-rays must be well known in order to calculate the solid angle subtended by the detector's crystal. The solid angle is calculated through a Monte Carlo program developed by Taylor and co-workers which is included in the GUPIXWIN software package. The H values are obtained from a set of experiments using standards. The results for the intrinsic efficiency of a Si(Li) detector are in good agreement with those obtained from Monte Carlo calculations and are compatible with a simple exponential law.

  3. Diode laser prostatectomy (VLAP): initial canine evaluation

    Science.gov (United States)

    Kopchok, George E.; Verbin, Chris; Ayres, Bruce; Peng, Shi-Kaung; White, Rodney A.

    1995-05-01

    This study evaluated the acute and chronic effects of diode laser (960 nm) prostatectomy using a Prolase II fiber in a canine model (n equals 5). The laser fiber consists of a 1000 um quartz fiber which reflects a cone of laser energy, at 45 degree(s) to the axis of the fiber, into the prostatic urethra (Visual Laser Ablation of Prostate). Perineal access was used to guide a 15.5 Fr cystoscope to the level of the prostate. Under visual guidance and continual saline irrigation, 60 watts of laser power was delivered for 60 seconds at 3, 9, and 12 o'clock and 30 seconds at the 6 o'clock (posterior) positions for a total energy fluence of 12,600 J. One prostate received an additional 60 second exposure at 3 and 9 o'clock for a total fluence of 19,800 J. The prostates were evaluated at one day (n equals 1) and 8 weeks (n equals 4). The histopathology of laser effects at one day show areas of necrosis with loss of glandular structures and stromal edema. Surrounding this area was a zone of degenerative glandular structures extending up to 17.5 mm (cross sectional diameter). The histopathology of the 8 week laser treated animals demonstrated dilated prostatic urethras with maximum cross- sectional diameter of 23.4 mm (mean equals 18.5 +/- 3.9 mm). This study demonstrates the effectiveness of diode laser energy for prostatic tissue coagulation and eventual sloughing. The results also demonstrate the safety of diode laser energy, with similar tissue response as seen with Nd:YAG laser, for laser prostatectomy.

  4. Initial testing of a pixelated silicon detector prototype in proton therapy.

    Science.gov (United States)

    Wroe, Andrew J; McAuley, Grant; Teran, Anthony V; Wong, Jeannie; Petasecca, Marco; Lerch, Michael; Slater, James M; Rozenfeld, Anatoly B

    2017-09-01

    As technology continues to develop, external beam radiation therapy is being employed, with increased conformity, to treat smaller targets. As this occurs, the dosimetry methods and tools employed to quantify these fields for treatment also have to evolve to provide increased spatial resolution. The team at the University of Wollongong has developed a pixelated silicon detector prototype known as the dose magnifying glass (DMG) for real-time small-field metrology. This device has been tested in photon fields and IMRT. The purpose of this work was to conduct the initial performance tests with proton radiation, using beam energies and modulations typically associated with proton radiosurgery. Depth dose and lateral beam profiles were measured and compared with those collected using a PTW parallel-plate ionization chamber, a PTW proton-specific dosimetry diode, EBT3 Gafchromic film, and Monte Carlo simulations. Measurements of the depth dose profile yielded good agreement when compared with Monte Carlo, diode and ionization chamber. Bragg peak location was measured accurately by the DMG by scanning along the depth dose profile, and the relative response of the DMG at the center of modulation was within 2.5% of that for the PTW dosimetry diode for all energy and modulation combinations tested. Real-time beam profile measurements of a 5 mm 127 MeV proton beam also yielded FWHM and FW90 within ±1 channel (0.1 mm) of the Monte Carlo and EBT3 film data across all depths tested. The DMG tested here proved to be a useful device at measuring depth dose profiles in proton therapy with a stable response across the entire proton spread-out Bragg peak. In addition, the linear array of small sensitive volumes allowed for accurate point and high spatial resolution one-dimensional profile measurements of small radiation fields in real time to be completed with minimal impact from partial volume averaging. © 2017 The Authors. Journal of Applied Clinical Medical Physics published

  5. Performance of SEM scintillation detector evaluated by modulation transfer function and detective quantum efficiency function.

    Science.gov (United States)

    Bok, Jan; Schauer, Petr

    2014-01-01

    In the paper, the SEM detector is evaluated by the modulation transfer function (MTF) which expresses the detector's influence on the SEM image contrast. This is a novel approach, since the MTF was used previously to describe only the area imaging detectors, or whole imaging systems. The measurement technique and calculation of the MTF for the SEM detector are presented. In addition, the measurement and calculation of the detective quantum efficiency (DQE) as a function of the spatial frequency for the SEM detector are described. In this technique, the time modulated e-beam is used in order to create well-defined input signal for the detector. The MTF and DQE measurements are demonstrated on the Everhart-Thornley scintillation detector. This detector was alternated using the YAG:Ce, YAP:Ce, and CRY18 single-crystal scintillators. The presented MTF and DQE characteristics show good imaging properties of the detectors with the YAP:Ce or CRY18 scintillator, especially for a specific type of the e-beam scan. The results demonstrate the great benefit of the description of SEM detectors using the MTF and DQE. In addition, point-by-point and continual-sweep e-beam scans in SEM were discussed and their influence on the image quality was revealed using the MTF. © 2013 Wiley Periodicals, Inc.

  6. Characteristic Performance Evaluation of a new SAGe Well Detector for Small and Large Sample Geometries

    International Nuclear Information System (INIS)

    Adekola, A.S.; Colaresi, J.; Douwen, J.; Jaederstroem, H.; Mueller, W.F.; Yocum, K.M.; Carmichael, K.

    2015-01-01

    Environmental scientific research requires a detector that has sensitivity low enough to reveal the presence of any contaminant in the sample at a reasonable counting time. Canberra developed the germanium detector geometry called Small Anode Germanium (SAGe) Well detector, which is now available commercially. The SAGe Well detector is a new type of low capacitance germanium well detector manufactured using small anode technology capable of advancing many environmental scientific research applications. The performance of this detector has been evaluated for a range of sample sizes and geometries counted inside the well, and on the end cap of the detector. The detector has energy resolution performance similar to semi-planar detectors, and offers significant improvement over the existing coaxial and Well detectors. Energy resolution performance of 750 eV Full Width at Half Maximum (FWHM) at 122 keV γ-ray energy and resolution of 2.0 - 2.3 keV FWHM at 1332 keV γ-ray energy are guaranteed for detector volumes up to 425 cm 3 . The SAGe Well detector offers an optional 28 mm well diameter with the same energy resolution as the standard 16 mm well. Such outstanding resolution performance will benefit environmental applications in revealing the detailed radionuclide content of samples, particularly at low energy, and will enhance the detection sensitivity resulting in reduced counting time. The detector is compatible with electric coolers without any sacrifice in performance and supports the Canberra Mathematical efficiency calibration method (In situ Object Calibration Software or ISOCS, and Laboratory Source-less Calibration Software or LABSOCS). In addition, the SAGe Well detector supports true coincidence summing available in the ISOCS/LABSOCS framework. The improved resolution performance greatly enhances detection sensitivity of this new detector for a range of sample sizes and geometries counted inside the well. This results in lower minimum detectable

  7. Characteristic Performance Evaluation of a new SAGe Well Detector for Small and Large Sample Geometries

    Energy Technology Data Exchange (ETDEWEB)

    Adekola, A.S.; Colaresi, J.; Douwen, J.; Jaederstroem, H.; Mueller, W.F.; Yocum, K.M.; Carmichael, K. [Canberra Industries Inc., 800 Research Parkway, Meriden, CT 06450 (United States)

    2015-07-01

    Environmental scientific research requires a detector that has sensitivity low enough to reveal the presence of any contaminant in the sample at a reasonable counting time. Canberra developed the germanium detector geometry called Small Anode Germanium (SAGe) Well detector, which is now available commercially. The SAGe Well detector is a new type of low capacitance germanium well detector manufactured using small anode technology capable of advancing many environmental scientific research applications. The performance of this detector has been evaluated for a range of sample sizes and geometries counted inside the well, and on the end cap of the detector. The detector has energy resolution performance similar to semi-planar detectors, and offers significant improvement over the existing coaxial and Well detectors. Energy resolution performance of 750 eV Full Width at Half Maximum (FWHM) at 122 keV γ-ray energy and resolution of 2.0 - 2.3 keV FWHM at 1332 keV γ-ray energy are guaranteed for detector volumes up to 425 cm{sup 3}. The SAGe Well detector offers an optional 28 mm well diameter with the same energy resolution as the standard 16 mm well. Such outstanding resolution performance will benefit environmental applications in revealing the detailed radionuclide content of samples, particularly at low energy, and will enhance the detection sensitivity resulting in reduced counting time. The detector is compatible with electric coolers without any sacrifice in performance and supports the Canberra Mathematical efficiency calibration method (In situ Object Calibration Software or ISOCS, and Laboratory Source-less Calibration Software or LABSOCS). In addition, the SAGe Well detector supports true coincidence summing available in the ISOCS/LABSOCS framework. The improved resolution performance greatly enhances detection sensitivity of this new detector for a range of sample sizes and geometries counted inside the well. This results in lower minimum detectable

  8. Evaluation of a digital optical ionizing radiation particle track detector

    International Nuclear Information System (INIS)

    Hunter, S.R.

    1987-06-01

    An ionizing radiation particle track detector is outlined which can, in principle, determine the three-dimensional spatial distribution of all the secondary electrons produced by the passage of ionizing radiation through a low-pressure (0.1 to 10 kPa) gas. The electrons in the particle track are excited by the presence of a high-frequency AC electric field, and two digital cameras image the optical radiation produced in electronic excitation collisions of the surroundings gas by the electrons. The specific requirements of the detector for neutron dosimetry and microdosimetry are outlined (i.e., operating conditions of the digital cameras, high voltage fields, gas mixtures, etc.) along with an estimate of the resolution and sensitivity achievable with this technique. The proposed detector is shown to compare favorable with other methods for obtaining the details of the track structure, particularly in the quality of the information obtainable about the particle track and the comparative simplicity and adaptability of the detector for measuring the secondary electron track structure for many forms of ionizing radiation over a wide range of energies

  9. Initial investigation into development of accelerated pavement evaluation (APE) vehicle

    CSIR Research Space (South Africa)

    Steyn, WJvdM

    2002-08-01

    Full Text Available n e n t d e f o r m a t i o n [ m m ] Test 1 Test 2 Test 3 Test 4 Initial indication of performance Indication of performance after traffic application TR-2003/9: Initial investigation into development of APE vehicle. 6 2... Restricted Contract Report Initial Investigation into Development of Accelerated Pavement Evaluation (APE) Vehicle. Author: WJvdM Steyn M de Beer PREPARED FOR: PREPARED BY: CSIR Transportek STEP CSIR Transportek PO...

  10. 78 FR 27441 - NIJ Evaluation of Hand-Held Cell Phone Detector Devices

    Science.gov (United States)

    2013-05-10

    ...The National Institute of Justice (NIJ) is soliciting interest in supplying hand-held cell phone detector devices for participation in an evaluation by the NIJ Corrections Technology Center of Excellence (CXCoE).

  11. National Evaluation of the Youth Firearms Violence Initiative.

    Science.gov (United States)

    Dunworth, Terence

    Between 1985 and 1994 the rate of violent criminal acts committed by juveniles rose sharply. Juvenile homicides committed with a handgun more than doubled. This bulletin discusses the national evaluation of the Youth Firearms Violence Initiative (YFVI), a program initiated by the Office of Community Oriented Policing Services (COPS) to fund…

  12. Evaluation of slow shutdown system flux detectors in Point Lepreau Generating Station - I: dynamic response characterization

    Energy Technology Data Exchange (ETDEWEB)

    Anghel, V.N.P. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Comeau, D. [New Brunswick Power Nuclear, Point Lepreau, New Brunswick (Canada); McKay, J.; Sur, B. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Taylor, D. [New Brunswick Power Nuclear, Point Lepreau, New Brunswick (Canada)

    2009-07-01

    CANDU reactors are protected against reactor overpower by two independent shutdown systems: Shut Down System 1 and 2 (SDS1 and SDS2). At the Point Lepreau Generating Station (PLGS), the shutdown systems can be actuated by measurements of the neutron flux by Platinum-clad Inconel In-Core Flux Detectors (ICFDs). These detectors have a complex dynamic behaviour, characterized by 'prompt' and 'delayed' components with respect to immediate changes in the in-core neutron flux. The dynamic response components need to be determined accurately in order to evaluate the effectiveness of the detectors for actuating the shutdown systems. The amplitudes of the prompt and the delayed components of individual detectors were estimated over a period of several years by comparison of archived detector response data with the computed local neutron flux evolution for SDS1 and SDS2 reactor trips. This was achieved by custom-designed algorithms. The results of this analysis show that the dynamic response of the detectors changes with irradiation, with the SDS2 detectors having 'prompt' signal components that decreased significantly with irradiation. Some general conclusions about detector aging effects are also drawn. (author)

  13. Performance Evaluation of New Generation CdZnTe Detectors for Safeguards Applications

    International Nuclear Information System (INIS)

    Ivanovs, V.; Mintcheva, J.; Berlizov, A.; Lebrun, A.

    2015-01-01

    Cadmium zinc telluride detectors (CdZnTe) have found a wide application in nondestructive assay measurements in the IAEA's verification practice. It is because of their form factor, usability, sensitivity and good spectral characteristics that they are extensively used for fresh and spent fuel attribute test measurements. Until now, the series of CdZnTe detectors utilized in the IAEA have covered the range of 5 mm 3 , 20 mm 3 , 60 mm 3 and 500mm 3 of sensitive volume. Recently, new CdZnTe detectors with improved spectroscopic characteristics and significantly bigger active volume have become available, owing to advances in crystal and detector manufacturing and signal processing technologies. The distinctive feature of this new technological development is the application of a low-intensity monochromatic optical stimulation with infrared (IR) light. The use of IR illumination with a properly chosen wavelength close to the absorption edge of the CdZnTe can significantly improve the performance of the detectors. Recognizing potential benefits of these detectors in safeguards applications, the IAEA has performed an evaluation of their performance characteristics. Under evaluation were several new detectors with sensitive volumes of 500 mm 3 , 1500 mm 3 and 4000 mm 3 , as well as all-in-one 60 mm 3 , 500 mm 3 and 1500 mm 3 integrated micro-spectrometers available from RITEC, Latvia. In addition to the standard performance characteristics, such as energy resolution, peak shape, efficiency, linearity, throughput and temperature stability, the potential use of the detectors for safeguards specific measurements, such as uranium enrichment with infinite thickness method, was of particular interest. The paper will describe the advances in the CdZnTe detector technology and present the results of their performance evaluation. (author)

  14. Using Population Dose to Evaluate Community-level Health Initiatives.

    Science.gov (United States)

    Harner, Lisa T; Kuo, Elena S; Cheadle, Allen; Rauzon, Suzanne; Schwartz, Pamela M; Parnell, Barbara; Kelly, Cheryl; Solomon, Loel

    2018-05-01

    Successful community-level health initiatives require implementing an effective portfolio of strategies and understanding their impact on population health. These factors are complicated by the heterogeneity of overlapping multicomponent strategies and availability of population-level data that align with the initiatives. To address these complexities, the population dose methodology was developed for planning and evaluating multicomponent community initiatives. Building on the population dose methodology previously developed, this paper operationalizes dose estimates of one initiative targeting youth physical activity as part of the Kaiser Permanente Community Health Initiative, a multicomponent community-level obesity prevention initiative. The technical details needed to operationalize the population dose method are explained, and the use of population dose as an interim proxy for population-level survey data is introduced. The alignment of the estimated impact from strategy-level data analysis using the dose methodology and the data from the population-level survey suggest that dose is useful for conducting real-time evaluation of multiple heterogeneous strategies, and as a viable proxy for existing population-level surveys when robust strategy-level evaluation data are collected. This article is part of a supplement entitled Building Thriving Communities Through Comprehensive Community Health Initiatives, which is sponsored by Kaiser Permanente, Community Health. Copyright © 2018 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  15. Initial beam test results from a silicon-strip detector with VLSI readout

    International Nuclear Information System (INIS)

    Adolphsen, C.; Litke, A.; Schwarz, A.

    1986-01-01

    Silicon detectors with 256 strips, having a pitch of 25 μm, and connected to two 128 channel NMOS VLSI chips each (Microplex), have been tested in relativistic charged particle beams at CERN and at the Stanford Linear Accelerator Center. The readout chips have an input channel pitch of 47.5 μm and a single multiplexed output which provides voltages proportional to the integrated charge from each strip. The most probable signal height from minimum ionizing tracks was 15 times the rms noise in any single channel. Two-track traversals with a separation of 100 μm were cleanly resolved

  16. Initial angle resolved measurements of fast neutrals using a multichannel linear AXUV detector system on LHD

    International Nuclear Information System (INIS)

    Veshchev, E. A.; Ozaki, T.; Goncharov, P. R.; Sudo, S.

    2006-01-01

    A new multichannel diagnostic for fast ion distribution studies has been developed and successfully tested on the Large Helical Device (LHD) in different plasma heating conditions. The diagnostic is based on a linear array AXUV detector consisting of 20 segments, charge sensitive preamplifiers, and a set of pulse height analysis channels. The main advantage of this system is the possibility to make time, energy, and angle-resolved measurements of charge exchange neutral particles in a single plasma discharge. This feature makes the new diagnostic a very helpful and powerful tool intended to contribute to the understanding of fast ion behavior in a complex helical plasma geometry like the one of LHD

  17. Initial evaluation of a full breast digital system

    International Nuclear Information System (INIS)

    Vano, E.; Fernandez, J.M.; Chevalier, M.; Moran, P.; Cepeda, T.; Fabra, A.; Alvarez Pedrosa, C.S.

    2001-01-01

    Full-field digital mammography systems have been developed for overcoming the limitations of the screen-film mammography. This work is focused on the system from GE Medical Systems (Senographe 2000) which has been recently installed in our institution. The imager consists of a thin Ics:Tl scintillator which is in narrow contact with an array of amorphous silicon detectors mounted in a single panel. The flat-panel detector is integrated in a x-ray system with a high-frequency generator Senographe DM and dual track anode of Mo and Rh with Mo and Rh filtration. The aim of this work is to analyse the defaults exposure factors set at the installation of the x-ray unit. The image quality has been evaluated by using one of the two phantoms recommended in the ACR Accreditation Program. Phantom images were obtained at each of the three available imaging modes: contrast (CNT), standard (STD) and DOSE. While maintaining the defaults of kilovoltage and anode/filter combination, phantom images were obtained at lower dose vales. The contrast noise ratio (CNR) was calculated for each of the low contrast objects (masses) of the phantom images and the detail visibility was also evaluated. The results obtained for both parameters reveal that similar image quality can be obtained with significant reductions of the average glandular dose. (author)

  18. Preliminary evaluation of a novel energy-resolved photon-counting gamma ray detector.

    Science.gov (United States)

    Meng, L-J; Tan, J W; Spartiotis, K; Schulman, T

    2009-06-11

    In this paper, we present the design and preliminary performance evaluation of a novel energy-resolved photon-counting (ERPC) detector for gamma ray imaging applications. The prototype ERPC detector has an active area of 4.4 cm × 4.4 cm, which is pixelated into 128 × 128 square pixels with a pitch size of 350 µm × 350µm. The current detector consists of multiple detector hybrids, each with a CdTe crystal of 1.1 cm × 2.2 cm × 1 mm, bump-bonded onto a custom-designed application-specific integrated circuit (ASIC). The ERPC ASIC has 2048 readout channels arranged in a 32 × 64 array. Each channel is equipped with pre- and shaping-amplifiers, a discriminator, peak/hold circuitry and an analog-to-digital converter (ADC) for digitizing the signal amplitude. In order to compensate for the pixel-to-pixel variation, two 8-bit digital-to-analog converters (DACs) are implemented into each channel for tuning the gain and offset. The ERPC detector is designed to offer a high spatial resolution, a wide dynamic range of 12-200 keV and a good energy resolution of 3-4 keV. The hybrid detector configuration provides a flexible detection area that can be easily tailored for different imaging applications. The intrinsic performance of a prototype ERPC detector was evaluated with various gamma ray sources, and the results are presented.

  19. Evaluation of activation detectors for the SPHINX project at the LR-0 experimental reactor

    International Nuclear Information System (INIS)

    Lahodova, Zdena; Viererbl, Ladislav; Novak, Evzen; Svadlenkova, Marie; Rypar, Vojtech

    2008-01-01

    This article summarizes the measurements of neutron fluence distributions carried out at the LR-0 research reactor (Czech Republic) in the frame of the SPHINX project. The influence of fluoride-salts or graphite filling in the SR-0 modules on neutron spectrum was studied using activation detectors. The activation detectors (Mn, Ni, In and Au) were evaluated to determine the changes in neutron field. The In and Au detectors were also irradiated with a cadmium cover. Five different configurations of reactor core (EROS) were realized. (authors)

  20. Evaluation of activation detectors for the SPHINX project at the LR-0 experimental reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lahodova, Zdena; Viererbl, Ladislav [Research Center Rez Ltd (Czech Republic); Novak, Evzen; Svadlenkova, Marie; Rypar, Vojtech [Nuclear Power and Safety Division, Nuclear Research Institute Rez plc (Czech Republic)

    2008-07-01

    This article summarizes the measurements of neutron fluence distributions carried out at the LR-0 research reactor (Czech Republic) in the frame of the SPHINX project. The influence of fluoride-salts or graphite filling in the SR-0 modules on neutron spectrum was studied using activation detectors. The activation detectors (Mn, Ni, In and Au) were evaluated to determine the changes in neutron field. The In and Au detectors were also irradiated with a cadmium cover. Five different configurations of reactor core (EROS) were realized. (authors)

  1. A wireless sensor network-based portable vehicle detector evaluation system.

    Science.gov (United States)

    Yoo, Seong-eun

    2013-01-17

    In an upcoming smart transportation environment, performance evaluations of existing Vehicle Detection Systems are crucial to maintain their accuracy. The existing evaluation method for Vehicle Detection Systems is based on a wired Vehicle Detection System reference and a video recorder, which must be operated and analyzed by capable traffic experts. However, this conventional evaluation system has many disadvantages. It is inconvenient to deploy, the evaluation takes a long time, and it lacks scalability and objectivity. To improve the evaluation procedure, this paper proposes a Portable Vehicle Detector Evaluation System based on wireless sensor networks. We describe both the architecture and design of a Vehicle Detector Evaluation System and the implementation results, focusing on the wireless sensor networks and methods for traffic information measurement. With the help of wireless sensor networks and automated analysis, our Vehicle Detector Evaluation System can evaluate a Vehicle Detection System conveniently and objectively. The extensive evaluations of our Vehicle Detector Evaluation System show that it can measure the traffic information such as volume counts and speed with over 98% accuracy.

  2. First photoelectron timing error evaluation of a new scintillation detector model

    International Nuclear Information System (INIS)

    Petrick, N.; Clinthorne, N.H.; Rogers, W.L.; Hero, A.O. III

    1991-01-01

    In this paper, a general timing system model for a scintillation detector developed is experimentally evaluated. The detector consists of a scintillator and a photodetector such as a photomultiplier tube or an avalanche photodiode. The model uses a Poisson point process to characterize the light output from the scintillator. This timing model was used to simulate a BGO scintillator with a Burle 8575 PMT using first photoelectron timing detection. Evaluation of the model consisted of comparing the RMS error from the simulations with the error from the actual detector system. The authors find that the general model compares well with the actual error results for the BGO/8575 PMT detector. In addition, the optimal threshold is found to be dependent upon the energy of the scintillation. In the low energy part of the spectrum, the authors find a low threshold is optimal while for higher energy pulses the optimal threshold increases

  3. First photoelectron timing error evaluation of a new scintillation detector model

    International Nuclear Information System (INIS)

    Petrick, N.; Clinthorne, N.H.; Rogers, W.L.; Hero, A.O. III

    1990-01-01

    In this paper, a general timing system model for a scintillation detector that was developed, is experimentally evaluated. The detector consists of a scintillator and a photodetector such as a photomultiplier tube or an avalanche photodiode. The model uses a Poisson point process to characterize the light output from the scintillator. This timing model was used to simulated a BGO scintillator with a Burle 8575 PMT using first photoelectron timing detection. Evaluation of the model consisted of comparing the RMS error from the simulations with the error from the actual detector system. We find that the general model compares well with the actual error results for the BGO/8575 PMT detector. In addition, the optimal threshold is found to be dependent upon the energy of the scintillation. In the low energy part of the spectrum, we find a low threshold is optimal while for higher energy pulses the optimal threshold increases

  4. Energy dependence evaluation of a ZnO detector for diagnostic X-ray beam

    International Nuclear Information System (INIS)

    Valença, C.P.V.; Silveira, M.A.L.; Macedo, M.A.; Santos, M.A.

    2015-01-01

    In the last decades the international organizations of human health and radiation protection have recommended certain care for using X-ray as a diagnosis tool. The current concern is to avoid any type of radiological accident or overdose to the patient. This can be done assessing the parameters of the X-ray equipment and there are various types of detectors available for that: ionizing chamber, semiconductor devices, etc. These detectors must be calibrated so that they can be used for any energy range and such a procedure is correlated with what is called the energy dependence of the detector. In accordance with the stated requirements of IEC 61267, the standard radiation quality beams and irradiation conditions (RQRs) are the tools and techniques for calibrating diagnostic X-Ray instruments and detectors. The purpose of this work is to evaluate the behavior of the energy dependence of a detector fabricated from a zinc oxide (ZnO) nanofilm. A Pantak industrial X-ray equipment was used to generate the RQR radiation quality beams and test three ZnO detector samples. A 6430 sub-femto-ammeter, Keithley, was used to bias the ZnO detector and simultaneously perform the output readings. The results showed that the ZnO device has some increase in its sensitivity to the ionizing radiation as the X-ray effective energy decreases unlike other types of semiconductor electronic devices typically used as an X-ray detector. We can be concluded that, after calibration, the ZnO device can be used as a diagnostic X-ray detector. (author)

  5. Evaluation of the energy dependence of a zinc oxide nanofilm X-ray detector

    International Nuclear Information System (INIS)

    Valenca, C.P.V.; Silveira, M.A.L.; Macedo, M.A.; Santos, L.A.P

    2015-01-01

    International organizations of human health and radiation protection have recommended certain care for using of the X-ray as a diagnosis tool to avoid any type of radiological accident or overdose to the patient. This can be done assessing the parameters of the X-ray equipment and there are various types of detectors available for that: ionizing chamber, electronic semiconductor devices, etc. These detectors must be calibrated so that they can be used for any energy range and such a procedure is correlated with what is called the energy dependence of the detector. In accordance with the stated requirements of IEC 61267, the standard radiation quality beams and irradiation conditions (RQRs) are the tools and techniques for calibrating diagnostic X-Ray instruments and detectors. The purpose of this work is to evaluate the behavior of the energy dependence of a detector fabricated from a zinc oxide (ZnO) nanofilm. A Pantak industrial X-ray equipment was used to generate the RQR radiation quality beams and test three ZnO detector samples. A 6430 sub-femto-ammeter, Keithley, was used to bias the ZnO detector and simultaneously perform the output readings. The results showed that the ZnO device has some increase in its sensitivity to the ionizing radiation as the X-ray effective energy decreases unlike other types of semiconductor electronic devices typically used as an X-ray detector. We can conclude that the ZnO device can be used as a diagnostic X-ray detector with an appropriate calibration. (author)

  6. Evaluation of In-Vacuum Imaging Plate Detector for X-Ray Diffraction Microscopy

    International Nuclear Information System (INIS)

    Nishino, Yoshinori; Takahashi, Yukio; Yamamoto, Masaki; Ishikawa, Tetsuya

    2007-01-01

    We performed evaluation tests of a newly developed in-vacuum imaging plate (IP) detector for x-ray diffraction microscopy. IP detectors have advantages over direct x-ray detection charge-coupled device (CCD) detectors, which have been commonly used in x-ray diffraction microscopy experiments, in the capabilities for a high photon count and for a wide area. The detector system contains two IPs to make measurement efficient by recording data with the one while reading or erasing the other. We compared speckled diffraction patterns of single particles taken with the IP and a direct x-ray detection CCD. The IP was inferior to the CCD in spatial resolution and in signal-to-noise ratio at a low photon count

  7. Evaluating U.S. States climate change initiatives

    Energy Technology Data Exchange (ETDEWEB)

    Silva, P

    2004-07-01

    This paper evaluates sub-federal efforts to mitigate climate change in the United States through a range of climate-relevant initiatives, identifying principal trends and detailing climate-relevant initiatives in several states. These strategies include renewable electricity mandates, State and regional greenhouse gas emissions inventories, mandatory greenhouse gas emissions reporting, State greenhouse gas emissions caps, greenhouse gas emissions reductions from motor vehicles, and greenhouse gas emissions cap-and-trade programs for electric generation in several States. Many municipalities in the United States are also pursuing a range of climate-relevant initiatives, those actions are beyond the scope of this paper, but it should be noted they also influence state and national consideration of climate-relevant initiatives in the United States. (author)

  8. Evaluating U.S. States climate change initiatives

    International Nuclear Information System (INIS)

    Silva, P.

    2004-01-01

    This paper evaluates sub-federal efforts to mitigate climate change in the United States through a range of climate-relevant initiatives, identifying principal trends and detailing climate-relevant initiatives in several states. These strategies include renewable electricity mandates, State and regional greenhouse gas emissions inventories, mandatory greenhouse gas emissions reporting, State greenhouse gas emissions caps, greenhouse gas emissions reductions from motor vehicles, and greenhouse gas emissions cap-and-trade programs for electric generation in several States. Many municipalities in the United States are also pursuing a range of climate-relevant initiatives, those actions are beyond the scope of this paper, but it should be noted they also influence state and national consideration of climate-relevant initiatives in the United States. (author)

  9. Evaluation of neutron flux density and power density with SPN-detectors and micro calorimeters

    International Nuclear Information System (INIS)

    Gehre, G.; Rindelhardt, U.; Seidenkranz, T.; Hogel, J.; Jirousek, V.; Vazek, J.

    1983-02-01

    During investigations with a special equipped fuel assembly in the Rheinsberg nuclear power station the neutron flux and the power density were evaluated from measurements with SPN-detectors and micro calorimeters. The reliability of both detector types, their measurement accuracy under different physical conditions and the usefulness of the developed calculation models are discussed in detail. The thermal flux and the power density evaluated with SPND's agree well with theoretical results. The values obtained through micro calorimeter measurements are systematic lower by about 18%. This deviation is probably a result of differences in the used calculation models. (author)

  10. Performance evaluation of continuous blood sampling system for PET study. Comparison of three detector-systems

    CERN Document Server

    Matsumoto, K; Sakamoto, S; Senda, M; Yamamoto, S; Tarutani, K; Minato, K

    2002-01-01

    To measure cerebral blood flow with sup 1 sup 5 O PET, it is necessary to measure the time course of arterial blood radioactivity. We examined the performance of three different types of continuous blood sampling system. Three kinds of continuous blood sampling system were used: a plastic scintillator-based beta detector (conventional beta detector (BETA)), a bismuth germinate (BGO)-based coincidence gamma detector (Pico-count flow-through detector (COINC)) and a Phoswich detector (PD) composed by a combination of plastic scintillator and BGO scintillator. Performance of these systems was evaluated for absolute sensitivity, count rate characteristic, sensitivity to background gamnra photons, and reproducibility for nylon tube geometry. The absolute sensitivity of the PD was 0.21 cps/Bq for sup 6 sup 8 Ga positrons at the center of the detector. This was approximately three times higher than BETA, two times higher than COINC. The value measured with BETA was stable, even when background radioactivity was incre...

  11. Evaluating a questionnaire to measure improvement initiatives in Swedish healthcare

    Directory of Open Access Journals (Sweden)

    Andersson Ann-Christine

    2013-02-01

    Full Text Available Abstract Background Quality improvement initiatives have expanded recently within the healthcare sector. Studies have shown that less than 40% of these initiatives are successful, indicating the need for an instrument that can measure the progress and results of quality improvement initiatives and answer questions about how quality initiatives are conducted. The aim of the present study was to develop and test an instrument to measure improvement process and outcome in Swedish healthcare. Methods A questionnaire, founded on the Minnesota Innovation Survey (MIS, was developed in several steps. Items were merged and answer alternatives were revised. Employees participating in a county council improvement program received the web-based questionnaire. Data was analysed by descriptive statistics and correlation analysis. The questionnaire psychometric properties were investigated and an exploratory factor analysis was conducted. Results The Swedish Improvement Measurement Questionnaire consists of 27 items. The Improvement Effectiveness Outcome dimension consists of three items and has a Cronbach’s alpha coefficient of 0.67. The Internal Improvement Processes dimension consists of eight sub-dimensions with a total of 24 items. Cronbach’s alpha coefficient for the complete dimension was 0.72. Three significant item correlations were found. A large involvement in the improvement initiative was shown and the majority of the respondents were satisfied with their work. Conclusions The psychometric property tests suggest initial support for the questionnaire to study and evaluate quality improvement initiatives in Swedish healthcare settings. The overall satisfaction with the quality improvement initiative correlates positively to the awareness of individual responsibilities.

  12. A New Approach for Evaluating Charge Transport Properties of Semiconductor Detectors

    International Nuclear Information System (INIS)

    Kim, Kyung O; Kim, Jong Kyung; Kim, Soon Young; Ha, Jang Ho

    2009-01-01

    The semiconductor detectors (e.g., CdTe, CdZnTe, and HgI 2 ) have been widely used for radiation detection and medical imaging because of its various outstanding features such as excellent energy resolution, wide bandgap energy, room temperature operation, and so on. Unfortunately, the performance of these detectors is mainly limited by the charge transport properties of semiconductor, especially the mobility-lifetime products (i.e., (μτ) e and ((μτ) h ). Hence, the analysis on the mobility-lifetime products is very important for evaluating correct characteristics of semiconductor detectors. A commonly used method to analyze the mobilitylifetime products is based on their responses to α particle. However, the α particle method cannot evaluate the ((μτ)h product in many cases, because a semiconductor detector operating at positive bias voltages often yields the energy spectrum without the peaks. This method is also known to be very sensitive to the experimental conditions as well as surface conditions of the detector. In this study, a new approach with gamma-ray instead of α particle was carried out to solve the determination difficulty of the ((μτ) h product with common method. The special relation between the two mobility-lifetime products, which we call the 'Nural equation', was also developed to simply obtain each parameter based on Hecht equation

  13. Dosimetric evaluation of a MOSFET detector for clinical application in photon therapy.

    Science.gov (United States)

    Kohno, Ryosuke; Hirano, Eriko; Nishio, Teiji; Miyagishi, Tomoko; Goka, Tomonori; Kawashima, Mitsuhiko; Ogino, Takashi

    2008-01-01

    Dosimetric characteristics of a metal oxide-silicon semiconductor field effect transistor (MOSFET) detector are studied with megavoltage photon beams for patient dose verification. The major advantages of this detector are its size, which makes it a point dosimeter, and its ease of use. In order to use the MOSFET detector for dose verification of intensity-modulated radiation therapy (IMRT) and in-vivo dosimetry for radiation therapy, we need to evaluate the dosimetric properties of the MOSFET detector. Therefore, we investigated the reproducibility, dose-rate effect, accumulated-dose effect, angular dependence, and accuracy in tissue-maximum ratio measurements. Then, as it takes about 20 min in actual IMRT for the patient, we evaluated fading effect of MOSFET response. When the MOSFETs were read-out 20 min after irradiation, we observed a fading effect of 0.9% with 0.9% standard error of the mean. Further, we applied the MOSFET to the measurement of small field total scatter factor. The MOSFET for dose measurements of small field sizes was better than the reference pinpoint chamber with vertical direction. In conclusion, we assessed the accuracy, reliability, and usefulness of the MOSFET detector in clinical applications such as pinpoint absolute dosimetry for small fields.

  14. Initial test results of an ionization chamber shower detector for a LHC luminosity monitor

    International Nuclear Information System (INIS)

    Datte, P.; Beche, J.-F.; Haguenauer, M.; Manfredi, P.F.; Manghisoni, M.; Millaud, J.; Placidi, M.; Ratti, L.; Riot, V.; Schmickler, H.; Speziali, V.; Turner, W.

    2002-01-01

    A novel, segmented, multi-gap, pressurized gas ionization chamber is being developed for optimization of the luminosity of the LHC. The ionization chambers are to be installed in the front quadrupole and zero degree neutral particle absorbers in the high luminosity IRs and sample the energy deposited near the maxima of the hadronic/electromagnetic showers in these absorbers. The ionization chambers are instrumented with low noise, fast, pulse shaping electronics to be capable of resolving individual bunch crossings at 40 MHz. In this paper we report the initial results of our second test of this instrumentation in an SPS external proton beam. Single 300 GeV protons are used to simulate the hadronic/electromagnetic shower produced by the forward collision products from the interaction regions of the LHC. The capability of instrumentations to measure the luminosity of individual bunches in a 40 MHz bunch train is demonstrated

  15. Evaluation of power history during power burst experiments in TRACY by combination of gamma-ray and thermal neutron detectors

    International Nuclear Information System (INIS)

    Yanagisawa, Hiroshi; Ohno, Akio

    2002-01-01

    A combination method using γ-ray and thermal neutron detectors was newly applied to the accurate evaluation of power histories during reactivity-initiated power burst experiments in the Transient Experiment Critical Facility (TRACY). During an initial power burst, the power history was determined using a fast response γ-ray ionization chamber, which was used because of its ability to exactly trace the power history within a short duration of the initial burst. After the initial burst, a micro fission chamber containing highly enriched uranium was used for the determination of the power history because the γ-ray ionization chamber could not be applied due to the contribution of delayed γ-rays from fission products. By the present method, the power histories were evaluated for the experiments in the range of 1.50 to 2.93$ of the reactivity insertion. It was found that the peak power and integrated power as determined by the previous method using only the micro fission chamber were underestimated to be 40% and 30% in maximum, respectively, in comparison with the results from the present evaluation. The numerical simulation performed by using the Monte Carlo method indicated that the underestimation could be comprehended by considering the time delay of thermal neutron detection of the fission chamber, which arose from the flight-time of neutrons from the TRACY core to the fission chamber. (author)

  16. Evaluation of silicon micro strip detectors with large read-out pitch

    International Nuclear Information System (INIS)

    Senyo, K.; Yamamura, K.; Tsuboyama, T.; Avrillon, S.; Asano, Y.; Bozek, A.; Natkaniec, Z.; Palka, H.; Rozanska, M.; Rybicki, K.

    1996-01-01

    For the development of the silicon micro-strip detector with the pitch of the readout strips as large as 250 μm on the ohmic side, we made samples with different structures. Charge collection was evaluated to optimize the width of implant strips, aluminum read-out strips, and/or the read-out scheme among strips. (orig.)

  17. A common evaluation framework for the African Health Initiative

    Science.gov (United States)

    2013-01-01

    Background The African Health Initiative includes highly diverse partnerships in five countries (Ghana, Mozambique, Rwanda, Tanzania, and Zambia), each of which is working to improve population health by strengthening health systems and to evaluate the results. One aim of the Initiative is to generate cross-site learning that can inform implementation in the five partnerships during the project period and identify lessons that may be generalizable to other countries in the region. Collaborators in the Initiative developed a common evaluation framework as a basis for this cross-site learning. Methods This paper describes the components of the framework; this includes the conceptual model, core metrics to be measured in all sites, and standard guidelines for reporting on the implementation of partnership activities and contextual factors that may affect implementation, or the results it produces. We also describe the systems that have been put in place for data management, data quality assessments, and cross-site analysis of results. Results and conclusions The conceptual model for the Initiative highlights points in the causal chain between health system strengthening activities and health impact where evidence produced by the partnerships can contribute to learning. This model represents an important advance over its predecessors by including contextual factors and implementation strength as potential determinants, and explicitly including equity as a component of both outcomes and impact. Specific measurement challenges include the prospective documentation of program implementation and contextual factors. Methodological issues addressed in the development of the framework include the aggregation of data collected using different methods and the challenge of evaluating a complex set of interventions being improved over time based on continuous monitoring and intermediate results. PMID:23819778

  18. Distributed Impact Detector System (DIDS) Health Monitoring System Evaluation

    Science.gov (United States)

    Prosser, William H.; Madaras, Eric I.

    2010-01-01

    Damage due to impacts from micrometeoroids and orbital debris is one of the most significant on-orbit hazards for spacecraft. Impacts to thermal protection systems must be detected and the damage evaluated to determine if repairs are needed to allow safe re-entry. To address this issue for the International Space Station Program, Langley Research Center and Johnson Space Center technologists have been working to develop and implement advanced methods for detecting impacts and resultant leaks. LaRC funded a Small Business Innovative Research contract to Invocon, Inc. to develop special wireless sensor systems that are compact, light weight, and have long battery lifetimes to enable applications to long duration space structures. These sensor systems are known as distributed impact detection systems (DIDS). In an assessment, the NASA Engineering and Safety Center procured two prototype DIDS sensor units to evaluate their capabilities in laboratory testing and field testing in an ISS Node 1 structural test article. This document contains the findings of the assessment.

  19. In-beam evaluation of a medium-size Resistive-Plate WELL gaseous particle detector

    CERN Document Server

    Moleri, L.

    2016-09-27

    In-beam evaluation of a fully-equipped medium-size 30$\\times$30 cm$^2$ Resistive Plate WELL (RPWELL) detector is presented. It consists here of a single element gas-avalanche multiplier with Semitron ESD225 resistive plate, 1 cm$^2$ readout pads and APV25/SRS electronics. Similarly to previous results with small detector prototypes, stable operation at high detection efficiency (>98%) and low average pad multiplicity (~1.2) were recorded with 150 GeV muon and high-rate pion beams, in Ne/(5%CH$_4$), Ar/(5%CH$_4$) and Ar/(7%CO$_2$). This is an important step towards the realization of robust detectors suitable for applications requiring large-area coverage; among them Digital Hadron Calorimetry.

  20. Performance evaluation of 3D-DDTC detectors on p-type substrates

    International Nuclear Information System (INIS)

    Dalla Betta, Gian-Franco; Boscardin, Maurizio; Bosisio, Luciano; Koehler, Michael; Parzefall, Ulrich; Ronchin, Sabina; Wiik, Liv; Zoboli, Andrea; Zorzi, Nicola

    2010-01-01

    In this work, we report on the noise and signal properties of n-on-p, 3D Double-Side Double Type Column (3D-DDTC) detectors fabricated at FBK-irst (Trento, Italy). Compared to full 3D detectors, devices made with this approach allow for a simpler fabrication process, but the efficiency and speed of the charge collection process critically depend on the column overlap and should be carefully evaluated. Measurements were performed on detectors in the microstrip configuration coupled to the ATLAS ABCD3T binary read-out. Spatially resolved signal efficiency tests made with a pulsed infrared laser setup and charge collection efficiency tests made with a β source setup are here reported.

  1. Performance evaluation of 3D-DDTC detectors on p-type substrates

    Energy Technology Data Exchange (ETDEWEB)

    Dalla Betta, Gian-Franco, E-mail: dallabe@disi.unitn.i [Dipartimento Ingegneria e Scienza dell' Informazione, Universita di Trento, and INFN Trento, via Sommarive 14, 38123 Povo di Trento (Italy); Boscardin, Maurizio [Fondazione Bruno Kessler (FBK-irst), via Sommarive 18, 38123 Povo di Trento (Italy); Bosisio, Luciano [Dipartimento di Fisica, Universita di Trieste, and INFN Trieste, via A. Valerio 2, 34127 Trieste (Italy); Koehler, Michael; Parzefall, Ulrich [Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg (Germany); Ronchin, Sabina [Fondazione Bruno Kessler (FBK-irst), via Sommarive 18, 38123 Povo di Trento (Italy); Wiik, Liv [Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg (Germany); Zoboli, Andrea [Dipartimento Ingegneria e Scienza dell' Informazione, Universita di Trento, and INFN Trento, via Sommarive 14, 38123 Povo di Trento (Italy); Zorzi, Nicola [Fondazione Bruno Kessler (FBK-irst), via Sommarive 18, 38123 Povo di Trento (Italy)

    2010-12-11

    In this work, we report on the noise and signal properties of n-on-p, 3D Double-Side Double Type Column (3D-DDTC) detectors fabricated at FBK-irst (Trento, Italy). Compared to full 3D detectors, devices made with this approach allow for a simpler fabrication process, but the efficiency and speed of the charge collection process critically depend on the column overlap and should be carefully evaluated. Measurements were performed on detectors in the microstrip configuration coupled to the ATLAS ABCD3T binary read-out. Spatially resolved signal efficiency tests made with a pulsed infrared laser setup and charge collection efficiency tests made with a {beta} source setup are here reported.

  2. Evaluation of coded aperture radiation detectors using a Bayesian approach

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Kyle, E-mail: mille856@andrew.cmu.edu [Auton Lab, The Robotics Institute, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States); Huggins, Peter [Auton Lab, The Robotics Institute, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States); Labov, Simon; Nelson, Karl [Lawrence Livermore National Laboratory, Livermore, CA (United States); Dubrawski, Artur [Auton Lab, The Robotics Institute, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States)

    2016-12-11

    We investigate tradeoffs arising from the use of coded aperture gamma-ray spectrometry to detect and localize sources of harmful radiation in the presence of noisy background. Using an example application scenario of area monitoring and search, we empirically evaluate weakly supervised spectral, spatial, and hybrid spatio-spectral algorithms for scoring individual observations, and two alternative methods of fusing evidence obtained from multiple observations. Results of our experiments confirm the intuition that directional information provided by spectrometers masked with coded aperture enables gains in source localization accuracy, but at the expense of reduced probability of detection. Losses in detection performance can however be to a substantial extent reclaimed by using our new spatial and spatio-spectral scoring methods which rely on realistic assumptions regarding masking and its impact on measured photon distributions.

  3. Using Concrete and Realistic Data in Evaluating Initial Visualization Designs

    DEFF Research Database (Denmark)

    Knudsen, Søren; Pedersen, Jeppe Gerner; Herdal, Thor

    2016-01-01

    We explore means of designing and evaluating initial visualization ideas, with concrete and realistic data in cases where data is not readily available. Our approach is useful in exploring new domains and avenues for visualization, and contrasts other visualization work, which typically operate...... under the assumption that data has already been collected, and is ready to be visualized. We argue that it is sensible to understand data requirements and evaluate the potential value of visualization before devising means of automatic data collection. We base our exploration on three cases selected...... the design case and problem, the manner in which we collected data, and the findings obtained from evaluations. Afterwards, we describe four factors of our data collection approach, and discuss potential outcomes from it....

  4. Economic gains stimulate negative evaluations of corporate sustainability initiatives

    Science.gov (United States)

    Makov, Tamar; Newman, George E.

    2016-09-01

    In recent years, many organizations have sought to align their financial goals with environmental ones by identifying strategies that maximize profits while minimizing environmental impacts. Examples of this `win-win' approach can be found across a wide range of industries, from encouraging the reuse of hotel towels, to the construction of energy efficient buildings, to the large-scale initiatives of multi-national corporations. Although win-win strategies are generally thought to reflect positively on the organizations that employ them, here we find that people tend to respond negatively to the notion of profiting from environmental initiatives. In fact, observers may evaluate environmental win-wins less favourably than profit-seeking strategies that have no environmental benefits. The present studies suggest that how those initiatives are communicated to the general public may be of central importance. Therefore, organizations would benefit from carefully crafting the discourse around their win-win initiatives to ensure that they avoid this type of backlash.

  5. Evaluation of K x-ray escape and crosstalk in CdTe detectors and multi-channel detectors

    International Nuclear Information System (INIS)

    Ohtsuchi, Tetsuro; Ohmori, Koichi; Tsutsui, Hiroshi; Baba, Sueki

    1995-01-01

    The simple structure of CdTe semiconductor detectors facilitates their downsizing, and their possible application to radiographic sensors has been studied. The escape of K X-rays from these detectors increases with reduction of their dimensions and affects the measurements of X- and gamma-ray spectra. K X-rays also produce crosstalk in multi-channel detectors with adjacent channels. Therefore, K X-rays which escape from the detector elements degrade both the precision of energy spectra and spatial resolution. The ratios of escape peak integrated counts to total photon counts for various sizes of CdTe single detectors were calculated for gamma rays using the Monte Carlo method. Also, escape and crosstalk ratios were simulated for the CdTe multi-channel detectors. The theoretical results were tested experimentally for 59.54-keV gamma rays from a 241 Am radioactive source. Results showed that escape ratios for single detectors were strongly dependent on element size and thickness. The escape and crosstalk ratios increased with closer channel pitch. The calculated results showed a good agreement with the experimental data. The calculations made it clear that K X-rays which escaped to neighboring channels induced crosstalk more frequently at smaller channel pitch in multichannel detectors. A radiation shielding grid which blocked incident photons between the boundary channels was also tested by experiment and by calculation. It was effective in reducing the probability of escape and crosstalk

  6. A Monte Carlo tool for evaluating VMAT and DIMRT treatment deliveries including planar detectors

    International Nuclear Information System (INIS)

    Asuni, G; Van Beek, T A; Venkataraman, S; McCurdy, B M C; Popescu, I A

    2013-01-01

    The aim of this work is to describe and validate a new general research tool that performs Monte Carlo (MC) simulations for volumetric modulated arc therapy (VMAT) and dynamic intensity modulated radiation therapy (DIMRT), simultaneously tracking dose deposition in both the patient CT geometry and an arbitrary planar detector system. The tool is generalized to handle either entrance or exit detectors and provides the simulated dose for the individual control-points of the time-dependent VMAT and DIMRT deliveries. The MC simulation tool was developed with the EGSnrc radiation transport. For the individual control point simulation, we rotate the patient/phantom volume only (i.e. independent of the gantry and planar detector geometries) using the gantry angle in the treatment planning system (TPS) DICOM RP file such that each control point has its own unique phantom file. After MC simulation, we obtained the total dose to the phantom by summing dose contributions for all control points. Scored dose to the sensitive layer of the planar detector is available for each control point. To validate the tool, three clinical treatment plans were used including VMAT plans for a prostate case and a head-and-neck case, and a DIMRT plan for a head-and-neck case. An electronic portal imaging device operated in ‘movie’ mode was used with the VMAT plans delivered to cylindrical and anthropomorphic phantoms to validate the code using an exit detector. The DIMRT plan was delivered to a novel transmission detector, to validate the code using an entrance detector. The total MC 3D absolute doses in patient/phantom were compared with the TPS doses, while 2D MC doses were compared with planar detector doses for all individual control points, using the gamma evaluation test with 3%/3 mm criteria. The MC 3D absolute doses demonstrated excellent agreement with the TPS doses for all the tested plans, with about 95% of voxels having γ 90% of percentage pixels with γ <1. We found that over

  7. Evaluation of Segmented Amorphous-Contact Planar Germanium Detectors for Heavy-Element Research

    Science.gov (United States)

    Jackson, Emily G.

    The challenge of improving our understanding of the very heaviest nuclei is at the forefront of contemporary low-energy nuclear physics. In the last two decades, "in-beam" spectroscopy experiments have advanced from Z=98 to Z=104, Rutherfordium, allowing insights into the dynamics of the fission barrier, high-order deformations, and pairing correlations. However, new detector technologies are needed to advance to even heavier nuclei. This dissertation is aimed at evaluating one promising new technology; large segmented planar germanium wafers for this area of research. The current frontier in gamma-ray spectroscopy involves large-volume (>9 cm thick) coaxial detectors that are position sensitive and employ gamma-ray "tracking". In contrast, the detectors assessed in this dissertation are relatively thin (~1 cm) segmented planar wafers with amorphous-germanium strip contacts that can tolerate extremely high gamma-ray count rates, and can accommodate hostile neutron fluxes. They may be the only path to heavier "in-beam" spectroscopy with production rates below 1 nanobarn. The resiliency of these detectors against neutron-induced damage is examined. Two detectors were deliberately subjected to a non-uniform neutron fluence leading to considerable degradation of performance. The neutrons were produced using the 7Li(p, n)7Be reaction at the UMass Lowell Van-de-Graaff accelerator with a 3.7-MeV proton beam incident on a natural Li target. The energy of the neutrons emitted at zero degrees was 2.0 MeV, close to the mean energy of the fission neutron spectrum, and each detector was exposed to a fluence >3.6 x109 n/cm2. A 3-D software "trap-corrector" gain-matching algorithm considerably restored the overall performance. Other neutron damage mitigation tactics were explored including over biasing the detector and flooding the detector with a high gamma-ray count rate. Various annealing processes to remove neutron damage were investigated. An array of very large diameter

  8. Performance evaluation of flat panel detector in x-ray fluoroscopy

    International Nuclear Information System (INIS)

    Grewal, R.K.; Mclean, I.D.

    2004-01-01

    Full text: Flat panel detectors are currently replacing the conventional image intensifiers in R-F imaging. We evaluated the performance of a biplane cardiac imaging system (Siemens Axiom Artis dBC), the image acquisition was based on a 25 cm diagonal digital fiat panel detector. Performance characteristics included image quality, typical patient entrance dose and measurement of input to the surface of flat detector. The results were compared with conventional image intensifier systems (Siemens Hicor Unit and Toshiba DPF 2000 A Biplane Unit) used in cardiac imaging at Westmead. Image quality and dose measurements were performed following standard protocols using Westmead test object and 20 cm solid water as absorber in the beam. For measurement of input to the surface of flat detector, 2 mm copper was placed on the collimator. Radcal 3cc and 180 cc ion chambers were used for dose measurements. Image quality: Our measurements on flat panel system indicate that high contrast resolution and threshold contrast is not affected by changing field size. This is expected due to minimum loss of signal in the imaging chain of digital systems and the independence of detector pixel size with change in field of view. While low contrast resolution was found to be similar to conventional systems, high contrast resolution was significantly superior using flat detector system for large and intermediate field of view (25-28 1p/cm against 18-20). Typical patient dose as measured using flat detector system was similar to the conventional Toshiba pulsed fluoroscopy system( ∼ 3 - 8 mGy/min depending on the field size). This was 40-50 % lower than our old Siemens hicore unit. Input to the surface of flat detector was found to vary with field size as is the case with a conventional II system. As described elsewhere, although there is no necessity to increase exposure or video gain in a digital magnification, digital data interpolation process introduces noise. As a result system

  9. Development and Evaluation of the Muon Trigger Detector Using a Resistive Plate Chamber

    International Nuclear Information System (INIS)

    Park, Byeong Hyeon; Kim, Yong Kyun; Kang, Jeong Soo; Kim, Young Jin; Choi, Ihn Jea; Kim, Chong; Hong, Byung Sik

    2011-01-01

    The PHENIX Experiment is the largest of the four experiments that have taken data at the Relativistic Heavy Ion Collider. PHENIX, the Pioneering High Energy Nuclear Interaction eXperiment, is designed specifically to measure direct probes of the collisions such as electrons, muons, and photons. The primary goal of PHENIX is to discover and study a new state of matter called the Quark-Gluon Plasma. Among many particles, muons coming from W-boson decay gives us key information to analyze the spin of proton. Resistive plate chambers are proposed as a suitable solution as a muon trigger because of their fast response and good time resolution, flexibility in signal readout, robustness and the relatively low cost of production. The RPC detectors for upgrade were assembled and their performances were evaluated. The procedure to make the detectors better was optimized and described in detail in this thesis. The code based on ROOT was written and by using this the performance of the detectors made was evaluated, and all of the modules for north muon arm met the criteria and installation at PHENIX completed in November 2009. As RPC detectors that we made showed fast response, capacity of covering wide area with a resonable price and good spatial resolution, this will give the opportunity for applications, such as diagnosis and customs inspection system

  10. Development and evaluation of the muon trigger detector using a resistive plate chamber

    International Nuclear Information System (INIS)

    Park, Byeong Hyeon

    2010-08-01

    The PHENIX Experiment is the largest of the four experiments that have taken data at the Relativistic Heavy Ion Collider. PHENIX, the Pioneering High Energy Nuclear Interaction experiment, is an exploratory experiment for the investigation of high energy collisions of heavy ions and protons. PHENIX is designed specifically to measure direct probes of the collisions such as electrons, muons, and photons. The primary goal of PHENIX is to discover and study a new state of matter called the Quark-Gluon Plasma. Among many particles, muons coming from W-boson decay gives us key information to analyze the spin of proton. Resistive plate chambers are proposed as a suitable solution as a muon trigger because of their fast response and good time resolution, flexibility in signal readout, robustness and the relatively low cost of production. The RPC detectors for upgrade were assembled and their performances were evaluated. The procedure to make the detectors better was optimized and described in detail in this thesis. The code based on ROOT was written and by using this the performance of the detectors made was evaluated, and all of the modules for north muon arm met the criteria and installation at PHENIX completed in November 2009. As RPC detectors that we made showed fast response, capacity of covering wide area with a resonable price and good spatial resolution, this will give the opportunity for applications,such as diagnosis and customs inspection system

  11. Evaluation of signal energy calculation methods for a light-sharing SiPM-based PET detector

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Qingyang [School of Automation and Electrical Engineering, University of Science & Technology Beijing, Beijing 100083 (China); Beijing Engineering Research Center of Industrial Spectrum Imaging, University of Science and Technology Beijing, Beijing 100083 (China); Ma, Tianyu; Xu, Tianpeng; Liu, Yaqiang; Wang, Shi [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Gu, Yu, E-mail: guyu@ustb.edu.cn [School of Automation and Electrical Engineering, University of Science & Technology Beijing, Beijing 100083 (China)

    2017-03-11

    Signals of a light-sharing positron emission tomography (PET) detector are commonly multiplexed to three analog pulses (E, X, and Y) and then digitally sampled. From this procedure, the signal energy that are critical to detector performance are obtained. In this paper, different signal energy calculation strategies for a self-developed SiPM-based PET detector, including pulse height and different integration methods, are evaluated in terms of energy resolution and spread of the crystal response in the flood histogram using a root-mean-squared (RMS) index. Results show that integrations outperform the pulse height. Integration using the maximum derivative value of the pulse E as the landmark point and 28 integrated points (448 ns) has the best performance in these evaluated methods for our detector. Detector performance in terms of energy and position is improved with this integration method. The proposed methodology is expected to be applicable for other light-sharing PET detectors.

  12. Mirage effect sensor with simple detector and with multiple detector: application to non destructive evaluation by photothermal excitation

    International Nuclear Information System (INIS)

    Charbonnier, Francois

    1990-01-01

    Local photothermal excitation of absorbing sample provides spatial and temporal temperature distribution inside this sample and its neighbouring medium. Optical, thermal and geometrical characteristics (thickness, presence of a defect...) modify surface temperature evolution. The realization of an optical instrument using mirage effect, sensitive and accurate, has came out of two industrial applications of non destructive evaluation: - automatic set-up for absolute measurement of thermal losses on concentrical pipes interface.- set up for quantitative measurement of optical absorption losses on multi coated laser mirrors. To obtain images and compensate acquisition slowness due to investigated thermal phenomenons, a synchronous integration signal process from a multi detector, is described. Experimental set-up using mirage effect detected by a linear CCD reading sensor is realized on this principle. Some examples prove feasibility of this parallel measurement along an excitation line. At last, high frequency parallel synchronous detection with sequential cut-out demodulation was tested and succeeded with a 50 kHz optical signal. (author) [fr

  13. Initial laboratory evaluation of color video cameras: Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    Terry, P.L.

    1993-07-01

    Sandia National Laboratories has considerable experience with monochrome video cameras used in alarm assessment video systems. Most of these systems, used for perimeter protection, were designed to classify rather than to identify intruders. The monochrome cameras were selected over color cameras because they have greater sensitivity and resolution. There is a growing interest in the identification function of security video systems for both access control and insider protection. Because color camera technology is rapidly changing and because color information is useful for identification purposes, Sandia National Laboratories has established an on-going program to evaluate the newest color solid-state cameras. Phase One of the Sandia program resulted in the SAND91-2579/1 report titled: Initial Laboratory Evaluation of Color Video Cameras. The report briefly discusses imager chips, color cameras, and monitors, describes the camera selection, details traditional test parameters and procedures, and gives the results reached by evaluating 12 cameras. Here, in Phase Two of the report, we tested 6 additional cameras using traditional methods. In addition, all 18 cameras were tested by newly developed methods. This Phase 2 report details those newly developed test parameters and procedures, and evaluates the results.

  14. Sub One-Hundred-PS Pyroelectric Detector Research and Evaluation Program at LASL

    International Nuclear Information System (INIS)

    McLellan, E.J.; Stotlar, S.C.

    1978-01-01

    Preliminary devices have been designed and evaluated with 1 ns and 90 ps FWHM CO 2 laser pulses. Good agreement between calculated and measured values of falltime and voltage responsivity has been obtained. The female SMA to male BNC connector appears to be the most desirable easily available package for sub-one-hundred ps CO 2 laser pulses. A new detector with an expected risetime of 13 ps has been designed

  15. Evaluating Teachers' Professional Development Initiatives: Towards an Extended Evaluative Framework

    Science.gov (United States)

    Merchie, Emmelien; Tuytens, Melissa; Devos, Geert; Vanderlinde, Ruben

    2018-01-01

    Evaluating teachers' professional development initiatives (PDI) is one of the main challenges for the teacher professionalisation field. Although different studies have focused on the effectiveness of PDI, the obtained effects and evaluative methods have been found to be widely divergent. By means of a narrative review, this study provides an…

  16. Initial performance studies of a general-purpose detector for multi-TeV physics at a 100 TeV pp collider

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S. V.; Beydler, M.; Kotwal, A. V.; Gray, L.; Sen, S.; Tran, N. V.; Yu, S. -S.; Zuzelski, J.

    2017-06-01

    This paper describes simulations of detector response to multi-TeV physics at the Future Circular Collider (FCC-hh) or Super proton-proton Collider (SppC) which aim to collide proton beams with a centre-of-mass energy of 100 TeV. The unprecedented energy regime of these future experiments imposes new requirements on detector technologies which can be studied using the detailed GEANT4 simulations presented in this paper. The initial performance of a detector designed for physics studies at the FCC-hh or SppC experiments is described with an emphasis on measurements of single particles up to 33 TeV in transverse momentum. The reconstruction of hadronic jets has also been studied in the transverse momentum range from 50 GeV to 26 TeV. The granularity requirements for calorimetry are investigated using the two-particle spatial resolution achieved for hadron showers.

  17. Evaluation of high temperature superconductive thermal bridges for space borne cryogenic detectors

    Science.gov (United States)

    Scott, Elaine P.

    1996-01-01

    Infrared sensor satellites are used to monitor the conditions in the earth's upper atmosphere. In these systems, the electronic links connecting the cryogenically cooled infrared detectors to the significantly warmer amplification electronics act as thermal bridges and, consequently, the mission lifetimes of the satellites are limited due to cryogenic evaporation. High-temperature superconductor (HTS) materials have been proposed by researchers at the National Aeronautics and Space Administration Langley's Research Center (NASA-LaRC) as an alternative to the currently used manganin wires for electrical connection. The potential for using HTS films as thermal bridges has provided the motivation for the design and the analysis of a spaceflight experiment to evaluate the performance of this superconductive technology in the space environment. The initial efforts were focused on the preliminary design of the experimental system which allows for the quantitative comparison of superconductive leads with manganin leads, and on the thermal conduction modeling of the proposed system. Most of the HTS materials were indicated to be potential replacements for the manganin wires. In the continuation of this multi-year research, the objectives of this study were to evaluate the sources of heat transfer on the thermal bridges that have been neglected in the preliminary conductive model and then to develop a methodology for the estimation of the thermal conductivities of the HTS thermal bridges in space. The Joule heating created by the electrical current through the manganin wires was incorporated as a volumetric heat source into the manganin conductive model. The radiative heat source on the HTS thermal bridges was determined by performing a separate radiant interchange analysis within a high-T(sub c) superconductor housing area. Both heat sources indicated no significant contribution on the cryogenic heat load, which validates the results obtained in the preliminary conduction

  18. Evaluation of moderately cooled pure NaI as a scintillator for position-sensitive PET detectors

    International Nuclear Information System (INIS)

    Wear, J.A.; Karp, J.S.; Haigh, A.T.; Freifelder, R.

    1996-01-01

    A new evaluation of pure NaI has been performed to determine if moderate cooling would lead to better performance than that of existing, activated NaI(Tl) position-sensitive detectors, particularly at high countrates. Using a freezer, an initial effort was performed to cool the crystal assembly to -90 C (183 K). At this temperature, pure NaI has a decay constant of 35 nsec, a light output which is about 20% that of room temperature NaI(Tl), and an energy resolution of 15%. For the PET applications the signal of room temperature (25 C) NaI(Tl) is normally pulse clipped, reducing the light output to 40% of the unclipped signal and yielding an energy resolution of 10.5%. Since the long decay of NaI(Tl) causes it to suffer more significantly than pure NaI from pre-pulse pileup, the difference in energy resolution between the two crystals at high countrates will be reduced. Also, a significantly shorter trigger deadtime with pure NaI will lead to a reduction in coincidence deadtime losses in PET. Computer simulations of large-area crystals operating at high countrates have been performed to quantify their trigger deadtime behavior and position resolution as a function of light output and pulse decay time. Having gained experience with the practical issues of cooling large crystals, measurements of position resolution have been performed with a NaI bar detector of similar geometry to the NaI(Tl) detectors in use in the PENN-PET scanner

  19. Beam splash effects on ATLAS silicon microstrip detectors evaluated using 1-w Nd YAG laser

    CERN Document Server

    Hara, K; Kohriki, T; Kuwano, T; Moorhead, G F; Terada, S; Unno, Y

    2005-01-01

    On an incident of accelerator beam loss, the tracking detector located close to the beam line is subjected to receive intensive radiation in a short period. We used a 1-W focused Nd: YAG laser and simulated the effects on the ATLAS microstrip detector. The laser corresponds to intensity of up to 1 multiplied by 109mips/pulse with a pulse width of about 10 ns. We observed breaks on Al strips on extreme conditions, depending on the laser intensity and bias voltage applied to the silicon sensor. The break can be interpreted as the oxide breakdown due to a large voltage locally created across the oxide by the intensive signal charges. The robustness of the Semiconductor Tracker (SCT) module including readout ASICs is also evaluated.

  20. Evaluation of CdZnTe as neutron detector around medical accelerators

    International Nuclear Information System (INIS)

    Martin-Martin, A.; Iniguez, M. P.; Luke, P. N.; Barquero, R.; Lorente, A.; Morchon, J.; Gallego, E.; Quincoces, G.; Marti-Climent, J. M.

    2009-01-01

    The operation of electron linear accelerators (LINACs) and cyclotrons can produce a mixed gamma-neutron field composed of energetic neutrons coming directly from the source and scattered lower energy neutrons. The thermal neutron detection properties of a non-moderated coplanar-grid CdZnTe (CZT) gamma-ray detector close to an 18 MV electron LINAC and an 18 MeV proton cyclotron producing the radioisotope 18 F for positron emission tomography are investigated. The two accelerators are operated at conditions producing similar thermal neutron fluence rates of the order of 104 cm -2 s -1 at the measurement locations. The counting efficiency of the CZT detector using the prompt 558 keV photopeak following 113 Cd thermal neutron capture is evaluated and a good neutron detection performance is found at the two installations. (authors)

  1. Evaluation Of Silicon Diodes As IN-SITU Cryogenic Field Emission Detectors For SRF Cavity Development

    International Nuclear Information System (INIS)

    Palczewski, Ari; Geng, Rongli

    2012-01-01

    We performed in-situ cryogenic testing of four silicon diodes as possible candidates for field emission (FE) monitors of superconducting radio frequency (SRF) cavities during qualification testing and in accelerator cryo-modules. We evaluated diodes from 2 companies - from Hamamatsu corporation model S1223-01; and from OSI Optoelectronics models OSD35-LR-A, XUV-50C, and FIL-UV20. The measurements were done by placing the diodes in superfluid liquid helium near the top of a field emitting 9-cell cavity during its vertical test. For each diode, we will discuss their viability as a 2K cryogenic detector for FE mapping of SRF cavities and the directionality of S1223-01 in such environments. We will also present calibration curves between the diodes and JLab's standard radiation detector placed above the Dewar's top plate.

  2. An evaluation of safety culture initiatives at BNSF Railway

    Science.gov (United States)

    2015-04-01

    Major safety culture (SC) initiatives initiated in the FRA Office of Research, Technology and Development (RT&D), such as Clear Signal for Action (CSA), the Investigation of Safety Related Occurrences Protocol (ISROP), the Participative Safety Rules ...

  3. Detector evaluation of a prototype amorphous selenium-based full field digital mammography system

    Science.gov (United States)

    Jesneck, Jonathan L.; Saunders, Robert S.; Samei, Ehsan; Xia, Jessie Q.; Lo, Joseph Y.

    2005-04-01

    This study evaluated the physical performance of a selenium-based direct full-field digital mammography prototype detector (Siemens Mammomat NovationDR), including the pixel value vs. exposure linearity, the modulation transfer function (MTF), the normalized noise power spectrum (NNPS), and the detective quantum efficiency (DQE). The current detector is the same model which received an approvable letter from FDA for release to the US market. The results of the current prototype are compared to those of an earlier prototype. Two IEC standard beam qualities (RQA-M2: Mo/Mo, 28 kVp, 2 mm Al; RQA-M4: Mo/Mo, 35 kVp, 2 mm Al) and two additional beam qualities (MW2: W/Rh, 28 kVp, 2 mm Al; MW4: W/Rh, 35 kVp, 2 mm Al) were investigated. To calculate the modulation transfer function (MTF), a 0.1 mm Pt-Ir edge was imaged at each beam quality. Detector pixel values responded linearly against exposure values (R2 0.999). As before, above 6 cycles/mm Mo/Mo MTF was slightly higher along the chest-nipple axis compared to the left-right axis. MTF was comparable to the previously reported prototype, with slightly reduced resolution. The DQE peaks ranged from 0.71 for 3.31 μC/kg (12.83 mR) to 0.4 for 0.48 μC/kg (1.86 mR) at 1.75 cycles/mm for Mo/Mo at 28 kVp. The DQE range for W/Rh at 28 kVP was 0.81 at 2.03 μC/kg (7.87 mR) to 0.50 at 0.50 μC/kg (1.94 mR) at 1 cycle/mm. NNPS tended to increase with greater exposures, while all exposures had a significant low-frequency component. Bloom and detector edge artifacts observed previously were no longer present in this prototype. The new detector shows marked noise improvement, with slightly reduced resolution. There remain artifacts due to imperfect gain calibration, but at a reduced magnitude compared to a prototype detector.

  4. SU-F-T-557: Evaluation of Detector Response in Rectangular Small Field Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Qureshi, A [University of Toledo, Toledo, Ohio (United States); Tanny, S [SUNY Upstate Medical University, Syracuse NY (United States); Parsai, E; Sperling, N [University of Toledo Medical Center, Toledo, OH (United States)

    2016-06-15

    Purpose: As stereotactic treatment modalities grow towards becoming the standard of care, the need for accurate dose computation in small fields is becoming increasingly essential. The purpose of this study is to evaluate the response of different detectors, intended for small field dosimetry, in jaw defined small rectangular fields by analyzing output factors from a stereotactic clinical accelerator. Methods: Two Dosimeters, the Exradin A26 Microionization Chamber (Standard Imaging) and Edge Diode Detector (Sun Nuclear) were used to measure output factors taken on the Varian Edge Stereotactic Linear accelerator. Measurements were taken at 6MV and 6FFF at 10cm depth, 100cm SSD in a 48×48×40cm3 Welhoffer BluePhantom2 (IBA) with X and Y jaws set from 0.6 to 2.0cm. Output factors were normalized to a 5×5cm2 machine-specific reference field. Measurements were made in the vertical orientation for the A26 and horizontal orientation for both the A26 and Edge. Output factors were measured as: OF{sub FS} = M{sub FS}/M{sub ref} where M{sub FS} and M{sub ref} are the measured signals for the clinical field and the reference field, respectively. Measured output factors were then analyzed to establish relative responses of the detectors in small fields. Results: At 6MV the Edge detector exhibited a variation in output factors dependent on jaw positioning (X-by-Y vs Y-by-X) of 5.7% of the 5×5cm reference output and a variation of 3.33% at 6FFF. The A26 exhibited variation of output factor dependent on jaw positioning of upto 7.7% of the 5×5cm reference field at 6MV and upto 5.33% at 6FFF. Conclusion: Both the Edge detector and A26 responded as expected at small fields however a dependence on the jaw positioning was noted. At 6MV and 6FFF the detector response showed an increased dependence on the positioning of the X jaws as compared to the positioning of the Y jaws.

  5. Evaluation of real-time digital pulse shapers with various HPGe and silicon radiation detectors

    International Nuclear Information System (INIS)

    Menaa, N.; D'Agostino, P.; Zakrzewski, B.; Jordanov, V.T.

    2011-01-01

    Real-time digital pulse shaping techniques allow synthesis of pulse shapes that have been difficult to realize using the traditional analog methods. Using real-time digital shapers, triangular/trapezoidal filters can be synthesized in real time. These filters exhibit digital control on the rise time, fall time, and flat-top of the trapezoidal shape. Thus, the trapezoidal shape can be adjusted for optimum performance at different distributions of the series and parallel noise. The trapezoidal weighting function (WF) represents the optimum time-limited pulse shape when only parallel and series noises are present in the detector system. In the presence of 1/F noise, the optimum WF changes depending on the 1/F noise contribution. In this paper, we report on the results of the evaluation of new filter types for processing signals from CANBERRA high purity germanium (HPGe) and passivated, implanted, planar silicon (PIPS) detectors. The objective of the evaluation is to determine improvements in performance over the current trapezoidal (digital) filter. The evaluation is performed using a customized CANBERRA digital signal processing unit that is fitted with new FPGA designs and any required firmware modifications to support operation of the new filters. The evaluated filters include the Cusp, one-over-F (1/F), and pseudo-Gaussian filters. The results are compared with the CANBERRA trapezoidal shaper.

  6. Development and initial evaluation of the SCI-FI/AT.

    Science.gov (United States)

    Jette, Alan M; Slavin, Mary D; Ni, Pengsheng; Kisala, Pamela A; Tulsky, David S; Heinemann, Allen W; Charlifue, Susie; Tate, Denise G; Fyffe, Denise; Morse, Leslie; Marino, Ralph; Smith, Ian; Williams, Steve

    2015-05-01

    To describe the domain structure and calibration of the Spinal Cord Injury Functional Index for samples using Assistive Technology (SCI-FI/AT) and report the initial psychometric properties of each domain. Cross sectional survey followed by computerized adaptive test (CAT) simulations. Inpatient and community settings. A sample of 460 adults with traumatic spinal cord injury (SCI) stratified by level of injury, completeness of injury, and time since injury. None SCI-FI/AT RESULTS: Confirmatory factor analysis (CFA) and Item response theory (IRT) analyses identified 4 unidimensional SCI-FI/AT domains: Basic Mobility (41 items) Self-care (71 items), Fine Motor Function (35 items), and Ambulation (29 items). High correlations of full item banks with 10-item simulated CATs indicated high accuracy of each CAT in estimating a person's function, and there was high measurement reliability for the simulated CAT scales compared with the full item bank. SCI-FI/AT item difficulties in the domains of Self-care, Fine Motor Function, and Ambulation were less difficult than the same items in the original SCI-FI item banks. With the development of the SCI-FI/AT, clinicians and investigators have available multidimensional assessment scales that evaluate function for users of AT to complement the scales available in the original SCI-FI.

  7. Initial ACTR retrieval technology evaluation test material recommendations

    International Nuclear Information System (INIS)

    Powell, M.R.

    1996-04-01

    Millions of gallons of radiaoctive waste are contained in underground storage tanks at Hanford (SE Washington). Techniques for retrieving much of this waste from the storage tanks have been developed. Current baseline approach is to use sluice jets for single-shell tanks and mixer pumps for double-shell tanks. The Acquire Commercial Technology for Retrieval (ACTR) effort was initiated to identify potential improvements in or alternatives to the baseline waste retrieval methods. Communications with a variety of vendors are underway to identify improved methods that can be implemented at Hanford with little or no additional development. Commercially available retrieval methods will be evaluated by a combination of testing and system-level cost estimation. Current progress toward developing waste simulants for testing ACTR candidate methods is reported; the simulants are designed to model 4 different types of tank waste. Simulant recipes are given for wet sludge, hardpan/dried sludge,hard saltcake, and soft saltcake. Comparisons of the waste and simulant properties are documented in this report

  8. P wave detector with PP rhythm tracking: evaluation in different arrhythmia contexts

    International Nuclear Information System (INIS)

    Portet, François

    2008-01-01

    Automatic detection of atrial activity (P waves) in an electrocardiogram (ECG) is a crucial task to diagnose the presence of arrhythmias. The P wave is difficult to detect and most of the approaches in the literature have been evaluated on normal sinus rhythms and rarely considered arrhythmia contexts other than atrial flutter and fibrillation. A novel knowledge-based P wave detector algorithm is presented. It is self-adaptive to the patient and able to deal with certain arrhythmias by tracking the PP rhythm. The detector has been tested on 12 records of the MIT-BIH arrhythmia database containing several ventricular and supra-ventricular arrhythmias. On the overall records, the detector demonstrates Se = 96.60% and Pr = 95.46%; for the normal sinus rhythm, it reaches Se = 97.76% and Pr = 96.80% and, in the case of Mobitz type II, it demonstrates Se = 72.79% and Pr = 99.51%. It also shows good performance for trigeminy and bigeminy, and outperforms some more sophisticated techniques. Although the results emphasize the difficulty of P wave detection in difficult arrhythmias (supra and ventricular tachycardias), it shows that domain knowledge can efficiently support signal processing techniques

  9. Evaluation of steam-to-sodium leak detectors in the sodium components test installation (SCTI)

    Energy Technology Data Exchange (ETDEWEB)

    McKee, J M; Simmons, W R

    1975-07-01

    Two nickel diffusion-membrane type hydrogen detectors were installed in the secondary sodium system of the Sodium Components Test Installation and evaluated during the 12-month performance test of the Modular Steam Generator (MSG). Hydrogen in the expansion tank cover gas was monitored with a gas chromatograph. During this period, numerous steam and hydrogen injections were made, simulating steam leaks into the sodium of an LMFBR steam generator. The response of the detectors was evaluated for leak sizes ranging from 10{sup -6} to 10{sup -4} 1b H{sub 2}O/sec, injection periods of 0.5 to 300 min, secondary sodium flow rates of 0.2 x 10{sup 6} to 1.5 x 10{sup 6} 1b/hr, and sodium temperatures of 400 to 950 deg. F. The response of the leak detection system was influenced significantly by two regimes of sodium temperature. Below 600 deg. F, the cover gas hydrogen detector gave the largest response; this is attributed to the long dissolution time of hydrogen bubbles relative to the transit time of hydrogen to the expansion tank. Above 600 deg. F, the hydrogen apparently dissolved rapidly and the detectors were much more effective in the sodium than in the cover gas. At least 75% of the hydrogen and 50% of the oxygen content of injected steam appeared as detectable activity if the reaction products were dispersed in the sodium stream and the sodium was above 600 deg. F. Hydrogen injections into semi-stagnant sodium at the MSG tube sheets were detected with better sensitivity than steam injections into the main sodium stream. It appeared that high local concentrations of hydrogen were quickly carried to the nearest detector by upward currents created by the injected gas. The alarm system functioned as expected, 2.1 ppb/min being the smallest rate-of-rise in hydrogen concentration to give an automatic alarm. With more sensitive rate-of-rise alarm settings, leaks as small as 2 x 10{sup -5} 1b H{sub 2}O/sec could be detected in a system such as the Clinch River Breeder

  10. Evaluation of steam-to-sodium leak detectors in the sodium components test installation (SCTI)

    International Nuclear Information System (INIS)

    McKee, J.M.; Simmons, W.R.

    1975-01-01

    Two nickel diffusion-membrane type hydrogen detectors were installed in the secondary sodium system of the Sodium Components Test Installation and evaluated during the 12-month performance test of the Modular Steam Generator (MSG). Hydrogen in the expansion tank cover gas was monitored with a gas chromatograph. During this period, numerous steam and hydrogen injections were made, simulating steam leaks into the sodium of an LMFBR steam generator. The response of the detectors was evaluated for leak sizes ranging from 10 -6 to 10 -4 1b H 2 O/sec, injection periods of 0.5 to 300 min, secondary sodium flow rates of 0.2 x 10 6 to 1.5 x 10 6 1b/hr, and sodium temperatures of 400 to 950 deg. F. The response of the leak detection system was influenced significantly by two regimes of sodium temperature. Below 600 deg. F, the cover gas hydrogen detector gave the largest response; this is attributed to the long dissolution time of hydrogen bubbles relative to the transit time of hydrogen to the expansion tank. Above 600 deg. F, the hydrogen apparently dissolved rapidly and the detectors were much more effective in the sodium than in the cover gas. At least 75% of the hydrogen and 50% of the oxygen content of injected steam appeared as detectable activity if the reaction products were dispersed in the sodium stream and the sodium was above 600 deg. F. Hydrogen injections into semi-stagnant sodium at the MSG tube sheets were detected with better sensitivity than steam injections into the main sodium stream. It appeared that high local concentrations of hydrogen were quickly carried to the nearest detector by upward currents created by the injected gas. The alarm system functioned as expected, 2.1 ppb/min being the smallest rate-of-rise in hydrogen concentration to give an automatic alarm. With more sensitive rate-of-rise alarm settings, leaks as small as 2 x 10 -5 1b H 2 O/sec could be detected in a system such as the Clinch River Breeder Reactor Plant. A preliminary

  11. Evaluation of detector array technology for the verification of advanced intensity-modulated radiotherapy

    Science.gov (United States)

    Hussien, Mohammad

    Purpose: Quality assurance (QA) for intensity modulated radiotherapy (IMRT) has evolved substantially. In recent years, various ionization chamber or diode detector arrays have become commercially available, allowing pre-treatment absolute dose verification with near real-time results. This has led to a wide uptake of this technology to replace point dose and film dosimetry and to facilitate QA streamlining. However, arrays are limited by their spatial resolution giving rise to concerns about their response to clinically relevant deviations. The common factor in all commercial array systems is the reliance on the gamma index (γ) method to provide the quantitative evaluation of the measured dose distribution against the Treatment Planning System (TPS) calculated dose distribution. The mathematical definition of the gamma index presents computational challenges that can cause a variation in the calculation in different systems. The purpose of this thesis was to evaluate the suitability of detector array systems, combined with their implementation of the gamma index, in the verification and dosimetry audit of advanced IMRT. Method: The response of various commercial detector array systems (Delta4®, ArcCHECK®, and the PTW 2D-Array seven29™ and OCTAVIUS II™ phantom combination, Gafchromic® EBT2 and composite EPID measurements) to simulated deliberate changes in clinical IMRT and VMAT plans was evaluated. The variability of the gamma index calculation in the different systems was also evaluated by comparing against a bespoke Matlab-based gamma index analysis software. A novel methodology for using a commercial detector array in a dosimetry audit of rotational radiotherapy was then developed. Comparison was made between measurements using the detector array and those performed using ionization chambers, alanine and radiochromic film. The methodology was developed as part of the development of a national audit of rotational radiotherapy. Ten cancer centres were

  12. A facility for long term evaluation and quality assurance of LHCb Vertex Detector modules

    CERN Document Server

    Marinho, F; Dimattia, R; Doherty, F; Dumps, R; Gersabeck, M; Melone, J; Parkes, C; Saavedra, A; Tobin, M

    2007-01-01

    This note describes the facility developed for long term evaluation and quality assurance of the LHCb Vertex Detector modules, known as the 'Glasgow Burn-in System'. This facility was developed to ensure that the modules conform to stringent quality levels. The system was able to uncover any weaknesses that could be introduced during the manufacturing and assembly of the components or during the transport of the modules to CERN. The system consisted of: a high resolution microscope for visual inspections; and a burn-in system to operate cooled modules in vacuum. The main components of the burn-in system were a vacuum system, a cooling system and a DAQ system.

  13. 38 CFR 21.376 - Travel expenses for initial evaluation and counseling.

    Science.gov (United States)

    2010-07-01

    ... initial evaluation and counseling. 21.376 Section 21.376 Pensions, Bonuses, and Veterans' Relief... Travel expenses for initial evaluation and counseling. When VA asks a disabled veteran to report to a designated place for an initial evaluation, reevaluation or counseling (including personal or vocational...

  14. Initial experiences in clinical application of the THORAX-FD: flat-panel detector radiography in thoracic diagnosis

    International Nuclear Information System (INIS)

    Herrmann, K.A.; Staebler, A.; Bonel, H.; Kulinna, C.; Holzknecht, N.; Reiser, M.F.; Geiger, B.; Boehm, S.; Maschke, M.

    2000-01-01

    The flat-panel detector closes the gap between radiography and the digital diagnostics equipment currently in use. In addition to the dose reduction that can be expected, the availability of diagnostic information in digital form enables the user to optimize the clinical workflow and to network radiography directly with a digital archiving and communication system. (orig.)

  15. System tests, initial operation and first data of the AMIGA muon detector for the Pierre Auger Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Pontz, Michael

    2013-07-01

    Investigating the energy region between 10{sup 17} eV and 4 x 10{sup 18} eV for primary cosmic particles will lead to a deeper understanding of the origin of cosmic rays. Effects of the transition from galactic to extragalactic origin are expected to be visible in this region. The knowledge of the composition of cosmic rays strongly depends on the hadronic interaction models, which are applied in the air shower reconstruction. Directly determining the number of muons from an air shower on ground level will improve the precision of the composition measurements by reducing the dependence on the models. The Pierre Auger Observatory is facing these challenges with an upgrade of the original detector setup. A denser sub-array of water Cherenkov detectors and a dedicated muon detector (MD) array constitute the AMIGA enhancement (Auger Muon and Infill for the Ground Array). Additional fluorescence telescopes constitute HEAT (High Elevation Auger Telescopes). Seven MD modules have been installed until mid 2012 in a first hexagon at the site of the Pierre Auger Observatory in Malarguee, Argentina. The corresponding readout electronics, and 19 more of these setups, were assembled and tested in Siegen to assure correct functionality. The detectors were incorporated in the trigger structure of the original surface detector (SD) array of the Pierre Auger Observatory and are now taking data synchronously. In the framework of this thesis, system tests have been developed, a pre-unitary cell (PUC) of seven modules has been successfully operated and their trigger has been synchronised with the SD trigger. First data from the MD have been analysed and have been combined with data from the SD.

  16. Comparative evaluations of surface contamination detectors calibration with radioactive sources - used in the Goiania accident, and standard sources

    International Nuclear Information System (INIS)

    Becker, P.H.B.; Marecha, M.H.H.

    1997-01-01

    The construction of Cs-137 standard flat sources for calibration of surface contamination detectors, used in the Goiania accident in 1987, is described and the procedures adopted are reported. At that time, standard sources were not available. Nowadays the Instituto de Radioprotecao e Dosimetria has standard sources acquired from Amersham which are used as calibration standards for surface contamination detectors. Comparative evaluations between the standard flat sources constructed for the accident and the calibrated ones are presented

  17. First evaluation of low frequency noise measurements of in core detector signals in the measuring assembly Rheinsberg

    International Nuclear Information System (INIS)

    Collatz, S.

    1982-01-01

    Reactor noise spectra of in core neutron detectors are measured in the low frequency range (0.03 Hz to 1 Hz) and evaluated. The increase of the effective noise signal value is due to pressure oscillations or oscillations of special steam volume portions. Thus boiling monitoring of reactor cores in PWR type reactors may be possible, if the low frequency noise of the whole set of in core detectors is taken into account

  18. Evaluation of the cooperative multi-carrier delivery initiatives.

    Science.gov (United States)

    2013-12-01

    In the last several years there has been a surge of interest in fostering more sustainable logistical operations in : urban areas. Under the umbrella of the generic term City Logistics, these initiatives try to take advantage of : the coordinating po...

  19. Symposium--The Safe Schools Healthy Students Initiative: The Evaluation Context in District Wide Initiatives.

    Science.gov (United States)

    Massey, Oliver T.; Armstrong, Kathleen; Lattimore, Pamela; Boroughs, Michael; Tucker, Joan; Santoro, Gina

    This report discusses the outcomes of two studies that investigated the effectiveness of the Safe Schools Healthy Students Initiative (SS/HSI), a federal grant program designed to promote healthy childhood development and prevent violence and substance abuse. The first study, titled "Results of a Longitudinal Study of Disciplinary Referrals…

  20. Initial site characterization and evaluation of radionuclide contaminated soil waste burial grounds

    International Nuclear Information System (INIS)

    Phillips, S.J.; Reisenauer, A.E.; Rickard, W.H.; Sandness, G.A.

    1977-02-01

    A survey of historical records and literature containing information on the contents of 300 Area and North Burial Grounds was completed. Existing records of radioactive waste location, type, and quantity within each burial ground facility were obtained and distributed to cooperating investigators. A study was then initiated to evaluate geophysical exploration techniques for mapping buried waste materials, waste containers, and trench boundaries. Results indicate that a combination of ground penetrating radar, magnetometer, metal detector, and acoustic measurements will be effective but will require further study, hardware development, and field testing. Drilling techniques for recovering radionuclide-contaminated materials and sediment cores were developed and tested. Laboratory sediment characterization and fluid transport and monitoring analyses were begun by installation of in situ transducers at the 300 North Burial Ground site. Biological transport mechanisms that control radionuclide movement at contaminated sites were also studied. Flora and fauna presently inhabiting specific burial ground areas were identified and analyzed. Future monitoring of specific mammal populations will permit determination of dose rate and pathways of contaminated materials contained in and adjacent to burial ground sites

  1. Influence of variation of etching conditions on the sensitivity of PADC detectors with a new evaluation method

    International Nuclear Information System (INIS)

    Fiechtner-Scharrer, A.; Mayer, S.; Boschung, M.; Whitelaw, A.

    2011-01-01

    At the Paul Scherrer Institut, a personal neutron dosimetry system based on chemically etched poly allyl diglycol carbonate (PADC) detectors and an automatic track counting (Autoscan 60) for neutron dose evaluations has been in routine use since 1998. Today, the hardware and the software of the Autoscan 60 are out of date, no spare components are available anymore and more sophisticated image-analysis systems are already developed. Therefore, a new evaluation system, the 'TASLIMAGE', was tested thoroughly in 2009 for linearity, reproducibility, influence of etching conditions and so forth, with the intention of replacing the Autoscan 60 in routine evaluations. The TASLIMAGE system is based on a microscope (high-quality Nikon optics) and an ultra-fast three-axis motorised control for scanning the detectors. In this paper, the TASLIMAGE system and its possibilities for neutron dose calculation are explained in more detail and the study of the influence of the variation of etching conditions on the sensitivity and background of the PADC detectors is described. The etching temperature and etching duration were varied, which showed that the etching conditions do not have a significant influence on the results of non-irradiated detectors. However, the sensitivity of irradiated detectors decreases by 5 % per 1 deg. C when increasing the etching temperature. For the variation of the etching duration, the influence on the sensitivity of irradiated detectors is less pronounced. (authors)

  2. Selection and evaluation of gamma decay standards for detector calibration using coincidence method

    International Nuclear Information System (INIS)

    Hlavac, S.

    2000-01-01

    Coincidence method for calibration of gamma detectors using suitable calibration standards with two cascading gamma rays is analyzed. From the list of recommended gamma ray standards currently under reevaluation by the CRP, 14 radionuclides were selected as the potential source candidates for the coincidence method. The following sources were selected 24 Na, 46 Sc, 60 Co, 66 Ga, 75 Se, 88 Y, Nb 94 , 111 In, 123m Te, 133 Ba, 134 Cs, 152 Eu, 154 Eu and 207 Bi. Reaction 11 B (p,γ) 12 C* was also selected as a source of high energy gamma rays. Experimental data on angular correlation coefficients for selected sources were collected from the literature and evaluated according to the recommended procedure. Theoretical angular correlation coefficients were calculated and compared to the evaluated data. (author)

  3. Initiatives in training program evaluation outside the nuclear utility industry

    International Nuclear Information System (INIS)

    Allen, C.J.

    1987-01-01

    Training literature is reviewed, and program evaluative practices outside the nuclear utility industry are reported. The findings indicate some innovations in philosophy and practice and program evaluation, although not necessarily in the context of evaluation as a route to assessing the impact of training. Program evaluation is described in the context of the impact of training, suggesting continued efforts to accept a multivariate concept of individual and organizational performance

  4. Assembly and evaluation of a pyroelectric detector bonded to vertically aligned multiwalled carbon nanotubes over thin silicon.

    Science.gov (United States)

    Theocharous, E; Theocharous, S P; Lehman, J H

    2013-11-20

    A novel pyroelectric detector consisting of a vertically aligned nanotube array on thin silicon (VANTA/Si) bonded to a 60 μm thick crystal of LiTaO₃ has been fabricated. The performance of the VANTA/Si-coated pyroelectric detector was evaluated using National Physical Laboratory's (NPL's) detector-characterization facilities. The relative spectral responsivity of the detector was found to be spectrally flat in the 0.8-24 μm wavelength range, in agreement with directional-hemispherical reflectance measurements of witness samples of the VANTA. The spatial uniformity of response of the test detector exhibited good uniformity, although the nonuniformity increased with increasing modulation frequency. The nonuniformity may be assigned either to the dimensions of the VANTA or the continuity of the bond between the VANTA/Si coating and the pyroelectric crystal substrate. The test detector exhibited a small superlinear response, which is similar to that of pyroelectric detectors coated with good quality gold-black coatings.

  5. Evaluation of radon measuring technique using passive detector activated carbon; Avaliacao da tecnica de medicao do radonio utilizando detector passivo com carvao ativado

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Paulo Roberto Rocha; Lessa, Edmilson de Lima; Oliveira, Evaldo Paulo de, E-mail: epoliveira@aluno.ird.gov.br [Instituto de Radioprotecao e Dosimetria, (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Div. de Radioprotecao Ambiental e Ocupacional

    2014-07-01

    This study aims to evaluate the efficiency of measuring the radioactive gas Radon ({sup 222} Rn) with passive detector activated carbon. Alpha Guard, exposure chamber, air sampler, default font Radio, calibrator flow, flow adjuster, ducts drivers: For this, various equipment to make the measurement system as were used. An assembly of such equipment, with specific sequence was used allowing for more efficient exposure of passive detectors Radon gas. Twenty samples were heated to remove moisture and then stored in desiccator until the experiment were made. The exhibition was held passive dosimeters being removed from the chamber, and one hour after, subjected to analysis by gamma spectrometry in germanium (HPGe) for an hour. Subsequently, other measurements were made at scheduled times and sequential for one hour. The results were presented in report form and spectra, measures and graphs generated by Alpha Guard were also extracted. Finally we calculated the efficiency of the passive meter activated carbon. (author)

  6. Psychophysical evaluation of the image quality of a dynamic flat-panel digital x-ray image detector using the threshold contrast detail detectability (TCDD) technique

    Science.gov (United States)

    Davies, Andrew G.; Cowen, Arnold R.; Bruijns, Tom J. C.

    1999-05-01

    We are currently in an era of active development of the digital X-ray imaging detectors that will serve the radiological communities in the new millennium. The rigorous comparative physical evaluations of such devices are therefore becoming increasingly important from both the technical and clinical perspectives. The authors have been actively involved in the evaluation of a clinical demonstration version of a flat-panel dynamic digital X-ray image detector (or FDXD). Results of objective physical evaluation of this device have been presented elsewhere at this conference. The imaging performance of FDXD under radiographic exposure conditions have been previously reported, and in this paper a psychophysical evaluation of the FDXD detector operating under continuous fluoroscopic conditions is presented. The evaluation technique employed was the threshold contrast detail detectability (TCDD) technique, which enables image quality to be measured on devices operating in the clinical environment. This approach addresses image quality in the context of both the image acquisition and display processes, and uses human observers to measure performance. The Leeds test objects TO[10] and TO[10+] were used to obtain comparative measurements of performance on the FDXD and two digital spot fluorography (DSF) systems, one utilizing a Plumbicon camera and the other a state of the art CCD camera. Measurements were taken at a range of detector entrance exposure rates, namely 6, 12, 25 and 50 (mu) R/s. In order to facilitate comparisons between the systems, all fluoroscopic image processing such as noise reduction algorithms, were disabled during the experiments. At the highest dose rate FDXD significantly outperformed the DSF comparison systems in the TCDD comparisons. At 25 and 12 (mu) R/s all three-systems performed in an equivalent manner and at the lowest exposure rate FDXD was inferior to the two DSF systems. At standard fluoroscopic exposures, FDXD performed in an equivalent

  7. Bubble detector's evaluation for neutron field measurement in a very known source

    Energy Technology Data Exchange (ETDEWEB)

    Ramalho, Eduardo; Silva, Ademir X. da, E-mail: ademir@nuclear.ufrj.b, E-mail: jdantas@con.ufrj.b [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEN/COPPE/UFRJ), RJ (Brazil). Programa de Engenharia Nuclear; Reina, Luiz, E-mail: reina@ien.gov.b [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Facure, Alessandro, E-mail: facure@cnen.gov.b [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

    2011-07-01

    Measurements on neutron fields, mainly for dosimetric purposes, have been a major concern for ionizing radiation workers, because of the radiation protection issues. The present work aims to study the using of bubble detectors in neutron dosimetry and the Bubble Detector Spectrometer (BDS) was chosen for this task. Several experiments were performed in order to obtain spectra from such devices and their respective analysis and then they were compared to those which were obtained by other ways. An Am-Be calibration neutron source from Instituto de Radioprotecao e Dosimetria/Comissao Nacional de Energia Nuclear (IRD/CNEN) was used and its spectrum was compared to the one obtained by BDS. The possibility of the use of such devices as ambient dosimeters was also evaluated. Despite the uncertainties, especially in the lowest energy thresholds, the spectrum from BDS is in good agreement with the known ones and the use of BDS as a dosimeter demands a more detailed study due to some characteristics of the Am-Be source that produce high uncertainties in low energy thresholds. (author)

  8. Test and evaluation of infrared detectors and arrays; Proceedings of the Meeting, Orlando, FL, Mar. 27-29, 1989

    Science.gov (United States)

    Hoke, Forney M.

    Papers on the testing and evaluation of IR detectors and arrays are presented, covering topics such as a short wavelength IR test system, pulse height analysis, the use of an expert system for IR detector testing, low-background IR focal plane testing, electron beam testing, high performance silicide Schottky photodiodes, the SDI organization focal plane test program, the absorption cross section of arsenic in silicon, and long wavelength IR hybrids. Other topics include low background radiometric detector measurements, an ultralow background dewar for IR detector characterization studies, a computer assisted mosaic array test station, a configurable detector array test station, automated detector material characterization capabilities, and a test system for mercury cadmium telluride photoconductor arrays. Additional topics include ionization dosimetry measurements inside a dewar for linac electron and californium-252 neutron environments, a radiation test facility using a variable-flux electron beam source, automated visual inspection of IR focal plane arrays, a titanium cryostat for low temperature radiation effects studies, a low dose rate gamma test facility, and the test and evaluation of stability in IR staring focal plane arrays after nonuniformity correction.

  9. Clock and trigger distribution for CBM-TOF quality evaluation of RPC super module detector assemblies

    Science.gov (United States)

    Li, C.; Huang, X.; Cao, P.; Wang, J.; An, Q.

    2018-03-01

    RPC Super module (SM) detector assemblies are used for charged hadron identification in the Time-of-Flight (TOF) spectrometer at the Compressed Baryonic Matter (CBM) experiment. Each SM contains several multi-gap Resistive Plate Chambers (MRPCs) and provides up to 320 electronic channels in total for high-precision time measurements. Time resolution of the Time-to-Digital Converter (TDC) is required to be better than 20 ps. During mass production, the quality of each SM needs to be evaluated. In order to meet the requirements, the system clock signal as well as the trigger signal should be distributed precisely and synchronously to all electronics modules within the evaluation readout system. In this paper, a hierarchical clock and trigger distribution method is proposed for the quality evaluation of CBM-TOF SM detectors. In a first stage, the master clock and trigger module (CTM) allocated in a 6U PXI chassis distributes the clock and trigger signals to the slave CTM in the same chassis. In a second stage, the slave CTM transmits the clock and trigger signals to the TDC readout module (TRM) through one optical link. In a third stage, the TRM distributes the clock and trigger signals synchronously to 10 individual TDC boards. Laboratory test results show that the clock jitter at the third stage is less than 4 ps (RMS) and the trigger transmission latency from the master CTM to the TDC is about 272 ns with 11 ps (RMS) jitter. The overall performance complies well with the required specifications.

  10. Evaluation of scintillators and semiconductor detectors to image three-photon positron annihilation for positron emission tomography

    International Nuclear Information System (INIS)

    Abuelhia, E.; Spyrou, N.M.; Kacperski, K.; College University, Middlesex Hospital, London

    2008-01-01

    Positron emission tomography (PET) is rapidly becoming the main nuclear imaging modality of the present century. The future of PET instrumentation relies on semiconductor detectors because of their excellent characteristics. Three-photon positron annihilation has been recently investigated as a novel imaging modality, which demands the crucial high energy resolution of semiconductor detector. In this work the evaluation of the NaI(Tl) scintillator and HPGe and CdZTe semiconductor detectors, to construct a simple three-photon positron annihilation scanner has been explored. The effect of detector and scanner size on spatial resolution (FWHM) is discussed. The characteristics: energy resolution versus count rate and point-spread function of the three-photon positron annihilation image profile from triple coincidence measurements were investigated. (author)

  11. Evaluation of the usefulness of a MOSFET detector in an anthropomorphic phantom for 6-MV photon beam.

    Science.gov (United States)

    Kohno, Ryosuke; Hirano, Eriko; Kitou, Satoshi; Goka, Tomonori; Matsubara, Kana; Kameoka, Satoru; Matsuura, Taeko; Ariji, Takaki; Nishio, Teiji; Kawashima, Mitsuhiko; Ogino, Takashi

    2010-07-01

    In order to evaluate the usefulness of a metal oxide-silicon field-effect transistor (MOSFET) detector as a in vivo dosimeter, we performed in vivo dosimetry using the MOSFET detector with an anthropomorphic phantom. We used the RANDO phantom as an anthropomorphic phantom, and dose measurements were carried out in the abdominal, thoracic, and head and neck regions for simple square field sizes of 10 x 10, 5 x 5, and 3 x 3 cm(2) with a 6-MV photon beam. The dose measured by the MOSFET detector was verified by the dose calculations of the superposition (SP) algorithm in the XiO radiotherapy treatment-planning system. In most cases, the measured doses agreed with the results of the SP algorithm within +/-3%. Our results demonstrated the utility of the MOSFET detector for in vivo dosimetry even in the presence of clinical tissue inhomogeneities.

  12. On site evaluation of three flat panel detectors for digital radiography

    International Nuclear Information System (INIS)

    Borasi, Giovanni; Nitrosi, Andrea; Ferrari, Paolo; Tassoni, Davide

    2003-01-01

    During a tender we evaluated the image performance of three commercially available active matrix flat panel imagers (AMFPI) for general radiography, one based on direct detection method (Se photoconductor) the other two on indirect detection method (CsI phosphor). Basic image quality parameters (MTF, NNPS, DQE) were evaluated with particular attention to dose and energy dependence. As it is known, presampling modulation transfer function (MTF) of selenium based detector is very high (at 70 kV, 2 cycles/mm, 2.5 μGy, about 0.80). Indirect detection panels exhibit a comparable (lower) resolution (at 70 kV, 2 cycles/mm, 2.5 μGy, MTF is about 0.34 for both the systems analyzed) and a more pronounced energy and dose dependence could also be noted in one of them. As a consequence of the very high resolution, the normalized noise power spectrum (NNPS) of the direct system is substantially flat, very similar to a white noise. Considering that the sensitive layer of all detectors is the same (0.5 mm), the relatively higher NNPS values are related to selenium absorption properties (lower Z respect to CsI:Tl) and detector inherent noise. NNPSs of the other systems, at low frequencies, are comparable but the frequency dependence is significantly different. At 70 kV, 2.5 μGy, 0.5 cycles/mm detective quantum efficiency (DQE) is about 0.35 for the direct detection system, and about the same (0.6) for the indirect ones. The combined effect of additive and multiplicative noise components makes DQE dependence on dose not monotonic. DQE present a maximum for an intermediate exposure. This complex behavior may be useful to characterize the systems in terms of the monodimensional integral over the frequency of DQE (IDQE). Both visual contrast-detail experiment and the direct evaluation of the signal-to-noise ratio confirmed, at least in a qualitative way, the system performances predicted by IDQE

  13. Report to DOE on the evaluation of initial trapping studies

    International Nuclear Information System (INIS)

    Breun, R.A.; Kesner, J.; Nonn, P.; Pian, T.; Post, R.S.; Scharer, J.; Smatlak, D.; Smith, D.; Yugo, J.; Yujiri, L.

    1978-12-01

    This report summarizes work up to Dec. 1, 1978 on the single mirror plug of Phaedrus. The design, construction and initial experiments proceeded without major problems. The results on RF trapping and heating steadily improved during the months of October and November with our best results being obtained during the last two weeks of November. These positive results are encouraging for RF heating in mirrors. The experiments to date have concentrated on heating stream gun plasmas. This plasma source has been well suited for our initial studies as it produces a hot, dense plasma over a long duration (approx. 1 msec). This has made diagnostics particularly straight forward. Because of the time scale we have carried out most of our work with the 200 kW source which is capable of running for long pulses

  14. Acute upper gastrointestinal bleeding (UGIB) - initial evaluation and management.

    Science.gov (United States)

    Khamaysi, Iyad; Gralnek, Ian M

    2013-10-01

    Acute upper gastrointestinal bleeding (UGIB) is the most common reason that the 'on-call' gastroenterologist is consulted. Despite the diagnostic and therapeutic capabilities of upper endoscopy, there is still significant associated morbidity and mortality in patients experiencing acute UGIB, thus this is a true GI emergency. Acute UGIB is divided into non-variceal and variceal causes. The most common type of acute UGIB is 'non-variceal' and includes diagnoses such as peptic ulcer (gastric and duodenal), gastroduodenal erosions, Mallory-Weiss tears, erosive oesophagitis, arterio-venous malformations, Dieulafoy's lesion, and upper GI tract tumours and malignancies. This article focuses exclusively on initial management strategies for acute upper GI bleeding. We discuss up to date and evidence-based strategies for patient risk stratification, initial patient management prior to endoscopy, potential causes of UGIB, role of proton pump inhibitors, prokinetic agents, prophylactic antibiotics, vasoactive pharmacotherapies, and timing of endoscopy. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Data evaluation and CNGS beam localization with the precision tracker of the OPERA detector

    International Nuclear Information System (INIS)

    Bick, D.

    2007-04-01

    In this diploma thesis, the data evaluation for the OPERA precision tracker is presented. Furthermore investigations of a precise CNGS beam localization with the precision tracker are performed. After an overview of past and present developments in neutrino physics, the OPERA detector is presented in this thesis. Emphasis is given to the precision tracker which has been partly commissioned in the end of the last year. A first analysis of the functionality with cosmic muons has been performed, as well as the inclusion of data in the OPERA software framework. Within this thesis some useful tools have been developed which are also presented. Finally, divergence effects from the nominal beam line of the CNGS neutrino beam and possible detection with the precision tracker are studied. (orig.)

  16. Data evaluation and CNGS beam localization with the precision tracker of the OPERA detector

    Energy Technology Data Exchange (ETDEWEB)

    Bick, D.

    2007-04-15

    In this diploma thesis, the data evaluation for the OPERA precision tracker is presented. Furthermore investigations of a precise CNGS beam localization with the precision tracker are performed. After an overview of past and present developments in neutrino physics, the OPERA detector is presented in this thesis. Emphasis is given to the precision tracker which has been partly commissioned in the end of the last year. A first analysis of the functionality with cosmic muons has been performed, as well as the inclusion of data in the OPERA software framework. Within this thesis some useful tools have been developed which are also presented. Finally, divergence effects from the nominal beam line of the CNGS neutrino beam and possible detection with the precision tracker are studied. (orig.)

  17. Performance evaluation of BGO block detectors used in positron emission tomography and a coincidence system

    International Nuclear Information System (INIS)

    Kim, J. H.; Choi, Y.; Lim, K. C.; Lee, M. Y.; Woo, S. K.; Lee, K. H.; Kim, S. E.; Choi, Y. S.; Kim, B. T.

    1999-01-01

    We investigated the basic performances of the BGO block detectors, which is used in the GE Advance positron emission tomography. The block detector is composed of 36 small BGO crystals coupled to two 2-channel photomultiplier tubes. In this study, we measured the crystal map and the intrinsic energy resolution of the detector. The coincidence signals between the detectors were also obtained using F-18. The intrinsic energy resolution of the block detector was 69% FWHM at 140 keV and 33% FWHM at 511 keV. High quality crystal map and the coincidence signals between the detectors were successfully obtained. The timing resolution of the detectors are being measured. The results of this study demonstrate the feasibility of developing high performance positron emission tomography

  18. Evaluation of Neutron Response of Criticality Accident Alarm System Detector to Quasi-Monoenergetic 24 keV Neutrons

    Science.gov (United States)

    Tsujimura, Norio; Yoshida, Tadayoshi; Yashima, Hiroshi

    The criticality accident alarm system (CAAS), which was recently developed and installed at the Japan Atomic Energy Agency's Tokai Reprocessing Plant, consists of a plastic scintillator combined with a cadmium-lined polyethylene moderator and thereby responds to both neutrons and gamma rays. To evaluate the neutron absorbed dose rate response of the CAAS detector, a 24 keV quasi-monoenergetic neutron irradiation experiment was performed at the B-1 facility of the Kyoto University Research Reactor. The detector's evaluated neutron response was confirmed to agree reasonably well with prior computer-predicted responses.

  19. Evaluation of neutron response of criticality accident alarm system detector to quasi-monoenergetic 24 keV neutrons

    International Nuclear Information System (INIS)

    Tsujimura, Norio; Yoshida, Tadayoshi; Yashima, Hiroshi

    2016-01-01

    The criticality accident alarm system (CAAS), which was recently developed and installed at the Japan Atomic Energy Agency's Tokai Reprocessing Plant, consists of a plastic scintillator combined with a cadmium-lined polyethylene moderator and thereby responds to both neutrons and gamma rays. To evaluate the neutron absorbed dose rate response of the CAAS detector, a 24 keV quasi-monoenergetic neutron irradiation experiment was performed at the B-1 facility of the Kyoto University Research Reactor. The detector's evaluated neutron response was confirmed to agree reasonably well with prior computer-predicted responses. (author)

  20. Evaluation of detectors for blood bioanalysis in Lu-177 and I-131 therapies for bone marrow dosimetry

    International Nuclear Information System (INIS)

    Degenhardt, Amilie Louize

    2016-01-01

    The measures traceability is mandatory for minimizing uncertainties in internal dosimetry for radiopharmaceuticals clinical studies and ensures the quality of the standard. Equipment should have resolution and efficiency compatible with radionuclides energies and, additionally, be able to quantify variations in human bodies' activities samples since the initial administration near the minimum residual activities. For testing three equipment (ionization chamber Capintec 25R, sodium iodine scintillator LTI Genesys Gamma-1 and high hyperpure germanium detector Canberra), they were prepared Lu-177 and I-131 radiation sources simulating patient's blood samples activities by adopting the following hypothesis: (1) initial activities according the Brazilian protocols; (2) blood volume in the whole body (5.3 L for adult men and 1.4 L for 5 years-old children); (3) effective half-lives (1.61 h and 42.9 h for Lu-177 bi-exponential adjustment and 15.7 h for I-131 mono-exponential adjustment); (4) sampling between 30 min and 168 h; (v) blood density adjustments. The standard sources were measured in the secondary standard ionization chamber Centronics IG11 at the Laboratorio Nacional de Metrologia das Radiacoes Ionizantes. The Capintec ionization chamber efficiencies ranged, respectively for I-131 and Lu-177, between (111.58±0.02)% and (102.27±0.01)% and HPGe semiconductor detector efficiencies ranged, respectively, between (89.40±0.03)% and (87.80±0.04)%. For the NaI detector, when the Lu-177 sources were positioned inside the detector the efficiencies ranged between (12.66±0.01)% and (11.54± 0.07)% and when the sources were positioned at 5 cm and 10 cm from the detector the efficiencies decreased to less than 5%. For I-131 sources positioned inside the detector, the efficiencies ranged between (29.76±0.21)% and (30.20±0.04)% and they decreased to less than 5% when they were positioned at 5 cm and 10 cm from the detector (deviation greater than 95

  1. Evaluation of a draft standard on performance specifications for health physics instrumentation. Initial results for radiological tests

    International Nuclear Information System (INIS)

    Swinth, K.L.; Kenoyer, J.L.; Mileham, A.P.; Kathren, R.L.; Selby, J.M.

    1983-06-01

    The draft ANSI standard N42.17D2 on performance specifications for health physics instrumentation is currently being evaluated by the Pacific Northwest Laboratory. The primary objective of the project is the evaluation of the applicability and practicality of the proposed standard through testing of a cross-section of currently available commercial instruments to determine how well they conform to the standard. The standard is being tested against instruments such as ionization chambers, G.M. detectors, alpha survey meters, and neutron dose equivalent survey meters. This paper presents results of the preliminary radiological performance tests on ionization chambers and G.M. detectors. This includes both the data generated during the tests and a discussion of procedures developed to perform the testing. Results are reported for response time, accuracy, precision, radiation overloads, and angular dependence. In addition, results are reported for parameters that affect instrument performance including battery lifetime, geotropism and stability. Initial test indicates that some of the instruments will not meet the criteria specified in ANSI N42.17D2. Results cover approximately 40 instruments that have been obtained by direct purchase, by loan from instrument vendors or by loan from others including DOE licensees

  2. [Evaluation of the Initial Stage Career Exploration Inventory (ISCEI)].

    Science.gov (United States)

    Adachi, Tomoko

    2010-06-01

    The Initial Stage Career Exploration Inventory (ISCEI) was designed to assess career exploration among students in the early stage of making career decisions. The reliability, validity, and applicability of the ISCEI were investigated. In Study 1, responses on the ISCEI from student participants (n = 294 : 69 men, 225 women) were factor analyzed. The results suggested a 3-factor structure consisting of "self-understanding," "information gathering" and "learning from others." Comparison between the ISCEI and self-improvement motive, vocational decisions, and career decision-making self-efficacy scales from the Career Exploration Survey (CES) indicated that the ISCEI had sufficient construct validity. Study 2 investigated the applicability of the ISCEI. The responses of student participants (n = 859 : 451 men, 408 women) on the ISCEI indicated high "self-understanding," neutral "information gathering," and comparatively low "learning from others" scores, which were similarly related to the CES as in Study 1. These findings indicate that the ISCEI can be used as a tool for understanding career exploration among students in the initial stage of making career decision.

  3. An Initial Evaluation of the NAG f90 Compiler

    Directory of Open Access Journals (Sweden)

    Michael Metcalf

    1992-01-01

    Full Text Available A few weeks before the formal publication of the ISO Fortran 90 Standard, NAG announced the world's first f90 compiler. We have evaluated the compiler by using it to assess the impact of Fortran 90 on the CERN Program Library.

  4. Clinical evaluation of digital angiographic system equipped with the Safire' flat-panel detector of a direct conversion type

    International Nuclear Information System (INIS)

    Miura, Yoshiaki; Miura, Yusuke; Goto, Keiichi

    2003-01-01

    This report presents a report on clinical evaluation of our newly developed flat-panel X-ray detector of a direct conversion type, designed to provide images of a resolution higher than, or at least equal to, that ensured by X-ray photographic films, in clinical digital X-ray cinematography. This new detector was named 'Safire' the acronym of 'Shimadzu advanced flat imaging receptor', emphasizing its high technological level, such as the capability to ensure high quality of images. The clinical evaluation of Shimadzu DIGITEX Premier digital angiography system, equipped with this new flat-panel X-ray detector of a direct conversion type, has been started in March, 2003, at the Kokura Memorial Hospital in Kyushu, Japan. (author)

  5. Dosimetric evaluation of semiconductor detectors for application in neutron dosimetry and microdosimetry in nuclear reactor and radiosurgical facilities

    International Nuclear Information System (INIS)

    Cardenas, Jose Patricio Nahuel

    2010-01-01

    The main objective of this research is the dosimetric evaluation of semiconductor components (surface barrier detectors and PIN photodiodes) for applications in dose equivalent measurements on low dose fields (fast and thermal fluxes) using an AmBe neutron source, the IEA-R1 reactor neutrongraphy facility (epithermal and thermal fluxes) and the Critical Unit facility IPEN/MB-01 (fast fluxes). As moderator compound to fast neutrons flux from the AmBe source was used paraffin and boron and polyethylene as converter for thermal and fast neutrons measurements. The resulting fluxes were used to the irradiation of semiconductor components (SSB - Surface Barrier Detector and PIN photodiodes). A mixed converter made of a borated polyethylene foil (Kodak) was also used. Monte Carlo simulation methodology was employed to evaluate analytically the optimal paraffin thickness. The obtained results were similar to the experimental data and allowed the evaluation of emerging neutron flux from moderator, as well as the fast neutron flux reaching the polyethylene covering the semiconductor sensitive surface. Gamma radiation levels were evaluated covering the whole detector with cadmium foil 1 mm thick, allowing thermal neutrons blockage and gamma radiation measurements. The IPEN/MB-01 facility was employed to evaluate the detector response for high neutron flux. The results were in good agreement with other studies published. Using the obtained spectra an approach to dose equivalent calculation was established. (author)

  6. Evaluation of Timepix silicon detector for the detection of 18F positrons

    Science.gov (United States)

    Wang, Q.; Tous, J.; Liu, Z.; Ziegler, S.; Shi, K.

    2014-05-01

    Timepix is an evolving energy and position sensitive pixel detector. It consists of a silicon detector (sensitive layer 300 μm thick) bump-bonded to the Timepix readout chip developed by the Medipix2 collaboration. This study aims to test the feasibility of using the acquired energy and position signals from Timepix for positron imaging. The signals of the commonly used fluorine-18 PET (positron emission tomography) tracer [18F]FDG were measured using Timepix operated both in single particle counting (Medipix) and in time over threshold (TOT) modes. The spatial resolution (SR) was measured using the absorber edge method (AEM) and was calculated from the over-sampled line spread function. The track of a positron in the Timepix detector was characterized as a cluster and the energy weighted centroid of each cluster was considered as readout for the position of the positron incidence. The measurement results were compared with theoretical predictions using Monte-Carlo simulations. In addition, imaging of a tissue slice of a mouse heart was analysed with reference to standard phosphor plate imaging. Our results show that the SR was improved from 177.1±4.1 μm (centroid without energy weighting) to 155.5±3.1 μm μm (centroid with energy weighting). About 12% enhancement of SR was achieved with energy information in TOT mode. The sensitivity of Timepix was 0.35 cps/Bq based on the measurements. The measuring background and the ratio between detected positrons and gamma rays were also evaluated and were found to be consistent with theoretical predictions. A small enhancement of image quality was also achieved by applying energy information to the data of the measured tissue sample. Our results show that the inclusion of energy information could slightly enhance the positron measurement compared to without energy information and the Timepix provides a high SR and sensitivity for positron detection. Thus, Timepix is a potentially effective tool for 2D positron imaging.

  7. Improving the Quality of Freeze Dried Rice: Initial Evaluations

    Science.gov (United States)

    2015-05-01

    a soft consistency and swells more during this period without disintegration of cell walls [10]. Evaluation of freshly cooked rice 4.1.2...synthetic/ plastic aroma and flavour. Comparison between Parboiled and Control-A 4.1.6. A more detailed series of rehydration tests with texture...the clumps rapidly and easily disintegrated into individual grains. Control-C and Parboiled differed in colour post- cooking due to the different

  8. Evaluating analytical ionization quenching correction models for 3D liquid organic scintillator detector

    Science.gov (United States)

    Alsanea, F.; Beddar, S.

    2017-05-01

    Proton therapy offers dosimetric advantage over conventional photon therapy due to the finite range of the proton beam, which improves dose conformity. However, one of the main challenges of proton beam therapy is verification of the complex treatment plans delivered to a patient. Thus, 3D measurements are needed to verify the complex dose distribution. A 3D organic scintillator detector is capable of such measurements. However, organic scintillators exhibit a non-linear relation to the ionization density called ionization quenching. The ionization quenching phenomenon in organic scintillators must be accounted for to obtain accurate dose measurements. We investigated the energy deposition by secondary electrons (EDSE) model to explain ionization quenching in 3D liquid organic scintillator when exposed to proton beams. The EDSE model was applied to volumetric scintillation measurement of proton pencil beam with energies of 85.6, 100.9, 144.9 and 161.9 MeV. The quenching parameter in EDSE model ρq was determined by plotting the total light output vs the initial energy of the ion. The results were compared to the Birks semi-empirical formula of scintillation light emission.

  9. Development and initial evaluation of a treatment decision dashboard.

    Science.gov (United States)

    Dolan, James G; Veazie, Peter J; Russ, Ann J

    2013-04-21

    For many healthcare decisions, multiple alternatives are available with different combinations of advantages and disadvantages across several important dimensions. The complexity of current healthcare decisions thus presents a significant barrier to informed decision making, a key element of patient-centered care.Interactive decision dashboards were developed to facilitate decision making in Management, a field marked by similarly complicated choices. These dashboards utilize data visualization techniques to reduce the cognitive effort needed to evaluate decision alternatives and a non-linear flow of information that enables users to review information in a self-directed fashion. Theoretically, both of these features should facilitate informed decision making by increasing user engagement with and understanding of the decision at hand. We sought to determine if the interactive decision dashboard format can be successfully adapted to create a clinically realistic prototype patient decision aid suitable for further evaluation and refinement. We created a computerized, interactive clinical decision dashboard and performed a pilot test of its clinical feasibility and acceptability using a multi-method analysis. The dashboard summarized information about the effectiveness, risks of side effects and drug-drug interactions, out-of-pocket costs, and ease of use of nine analgesic treatment options for knee osteoarthritis. Outcome evaluations included observations of how study participants utilized the dashboard, questionnaires to assess usability, acceptability, and decisional conflict, and an open-ended qualitative analysis. The study sample consisted of 25 volunteers - 7 men and 18 women - with an average age of 51 years. The mean time spent interacting with the dashboard was 4.6 minutes. Mean evaluation scores on scales ranging from 1 (low) to 7 (high) were: mechanical ease of use 6.1, cognitive ease of use 6.2, emotional difficulty 2.7, decision-aiding effectiveness 5

  10. Mexico City Air Quality Research Initiative; Volume 5, Strategic evaluation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-03-01

    Members of the Task HI (Strategic Evaluation) team were responsible for the development of a methodology to evaluate policies designed to alleviate air pollution in Mexico City. This methodology utilizes information from various reports that examined ways to reduce pollutant emissions, results from models that calculate the improvement in air quality due to a reduction in pollutant emissions, and the opinions of experts as to the requirements and trade-offs that are involved in developing a program to address the air pollution problem in Mexico City. The methodology combines these data to produce comparisons between different approaches to improving Mexico City`s air quality. These comparisons take into account not only objective factors such as the air quality improvement or cost of the different approaches, but also subjective factors such as public acceptance or political attractiveness of the different approaches. The end result of the process is a ranking of the different approaches and, more importantly, the process provides insights into the implications of implementing a particular approach or policy.

  11. Evaluation of InGaAS array detector suitability to space environment

    Science.gov (United States)

    Tauziede, L.; Beulé, K.; Boutillier, M.; Bernard, F.; Reverchon, J.-L.; Buffaz, A.

    2017-11-01

    InGaAs material has a natural cutoff wavelength of 1.65µm so it is naturally suitable for detection in Short Wavelength InfraRed (SWIR) spectral range. Regarding Earth Observation Spacecraft missions this spectral range can be used for the CO2 concentration measurements in the atmosphere. CNES (French Space agency) is studying a new mission, Microcarb with a spectral band centered on 1.6µm wavelength. InGaAs detector looks attractive for space application because its low dark current allows high temperature operation, reducing by the way the needed instrument resources. The Alcatel Thales III-VLab group has developed InGaAs arrays technology (320x256 & 640x512) that has been studied by CNES, using internal facilities. Performance tests and technological evaluation were performed on a 320x256 pixels array with a pitch of 30µm. The aim of this evaluation was to assess this new technology suitability for space applications. The carried out test plan includes proton radiations with Random Telegraph Signal (RTS) study, operating lifetest and evolution of performances as a function of the operating temperature.

  12. Performance evaluation of a retrofit digital detector-based mammography system.

    Science.gov (United States)

    Marshall, Nicholas W; van Ongeval, Chantal; Bosmans, Hilde

    2016-02-01

    A retrofit flat panel detector was integrated with a GE DMR+ analog mammography system and characterized using detective quantum efficiency (DQE). Technical system performance was evaluated using the European Guidelines protocol, followed by a limited evaluation of clinical image quality for 20 cases using image quality criteria in the European Guidelines. Optimal anode/filter selections were established using signal difference-to-noise ratio measurements. Only small differences in peak DQE were seen between the three anode/filter settings, with an average value of 0.53. For poly(methyl methacrylate) (PMMA) thicknesses above 60 mm, the Rh/Rh setting was the optimal anode/filter setting. The system required a mean glandular dose of 0.54 mGy at 30 kV Rh/Rh to reach the Acceptable gold thickness limit for 0.1 mm details. Imaging performance of the retrofit unit with the GE DMR+ is notably better than of powder based computed radiography systems and is comparable to current flat panel FFDM systems. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  13. Evaluation of response function of moderating-type neutron detector and application to environmental neutron measurement

    International Nuclear Information System (INIS)

    Kosako, Toshiso; Nakamura, Takashi; Iwai, Satoshi; Katsuki, Shinji; Kamata, Masashi.

    1983-08-01

    The energy-dependent response function of a multi-cylinder moderating-type BF 3 counter, so-called Bonner counter, was calculated by the time-dependent multi-group Monte Carlo code, TMMCR. The calculated response function was evaluated experimentally for neutron energy below about 50 keV down to epithermal energy by the time-of-flight method combining with a large lead pile at the Nuclear Engineering Research Laboratory, University of Tokyo and also above 50 keV by using the monoenergetic neutron standard field a t the Electrotechnical Laboratory. The time delay in the polyethylene moderator of the Bonner counter due to multiple collisions with hydrogen was analyzed by the TMMCR code and used for the time-spectrum analysis of the time-of-flight measurement. The response function obtained by these two experiments showed good agreement with the calculated results. This Bonner counter having a response function evaluated from thermal to MeV energy range was used for spectrometry and dosimetry of environmental neutrons around some nuclear facilities. The neutron spectra and dose measured in the environment around a 252 Cf fission source, fast neutron source reactor and electron synchrotron were all in good agreement with the calculated results and the measured results with other neutron detectors. (author)

  14. Evaluation of photoionization detector performance in photocatalytic studies for removing volatile organic compounds

    Directory of Open Access Journals (Sweden)

    Masoud Rismanchian

    2012-01-01

    Full Text Available Aims: The aim of this study was to evaluate the performance of photoionization detector (PID system as a substitution for gas chromatography in the measurement of a 3 xylene isomer mixtures as a representative of the volatile organic compounds in photocatalytic studies. Materials and Methods: This study has been carried out by using test setup for generating known concentrations from equal ratio of 3 xylene isomers. The concentration values to be evaluated were classified into 4 concentration ranges from 0.1 of threshold limit values (TLV to 2 of TLV to evaluate the PID system appliance compared with that in the reference method. The test was done 4 times for each evaluation concentration in 3 relative humidity levels (0%, 20%, and 80%. Results: The correlation between the PID results and the National Institue of Occupational Safety and Health (NIOSH reference method results in an atmosphere with relative humidity of 0%, 20%, and 80% were good and, respectively, were 0.993, 0.992, and 0.991 and total correlation was 0.989. The paired t test indicates a significant difference between actual concentrations in reference method and the extracted concentration from PID. Conclusions: Although the results presented by PID in the present study are different from those extracted from the reference method (from 10 to 260 ppm, the equipment response is linear. So, the results are acceptable in photocatalytic studies in case the contaminant concentration is measured by the same equipment either before or after the reactor for calculation of the removal efficiency. PID calibration with the test material(s is recommended.

  15. Performance evaluation of a high-resolution brain PET scanner using four-layer MPPC DOI detectors

    Science.gov (United States)

    Watanabe, Mitsuo; Saito, Akinori; Isobe, Takashi; Ote, Kibo; Yamada, Ryoko; Moriya, Takahiro; Omura, Tomohide

    2017-09-01

    A high-resolution positron emission tomography (PET) scanner, dedicated to brain studies, was developed and its performance was evaluated. A four-layer depth of interaction detector was designed containing five detector units axially lined up per layer board. Each of the detector units consists of a finely segmented (1.2 mm) LYSO scintillator array and an 8  ×  8 array of multi-pixel photon counters. Each detector layer has independent front-end and signal processing circuits, and the four detector layers are assembled as a detector module. The new scanner was designed to form a detector ring of 430 mm diameter with 32 detector modules and 168 detector rings with a 1.2 mm pitch. The total crystal number is 655 360. The transaxial and axial field of views (FOVs) are 330 mm in diameter and 201.6 mm, respectively, which are sufficient to measure a whole human brain. The single-event data generated at each detector module were transferred to the data acquisition servers through optical fiber cables. The single-event data from all detector modules were merged and processed to create coincidence event data in on-the-fly software in the data acquisition servers. For image reconstruction, the high-resolution mode (HR-mode) used a 1.2 mm2 crystal segment size and the high-speed mode (HS-mode) used a 4.8 mm2 size by collecting 16 crystal segments of 1.2 mm each to reduce the computational cost. The performance of the brain PET scanner was evaluated. For the intrinsic spatial resolution of the detector module, coincidence response functions of the detector module pair, which faced each other at various angles, were measured by scanning a 0.25 mm diameter 22Na point source. The intrinsic resolutions were obtained with 1.08 mm full width at half-maximum (FWHM) and 1.25 mm FWHM on average at 0 and 22.5 degrees in the first layer pair, respectively. The system spatial resolutions were less than 1.0 mm FWHM throughout the whole FOV, using a

  16. Initial Clinical Evaluation of the Modular Prosthetic Limb

    Directory of Open Access Journals (Sweden)

    Briana N. Perry

    2018-03-01

    Full Text Available The Modular Prosthetic Limb (MPL was examined for its feasibility and usability as an advanced, dexterous upper extremity prosthesis with surface electromyography (sEMG control in with two individuals with below-elbow amputations. Compared to currently marketed prostheses, the MPL has a greater number of sequential and simultaneous degrees of motion, as well as wrist modularity, haptic feedback, and individual digit control. The MPL was successfully fit to a 33-year-old with a trans-radial amputation (TR01 and a 30-year-old with a wrist disarticulation amputation (TR02. To preserve anatomical limb length, we adjusted the powered degrees of freedom of wrist motion between users. Motor training began with practicing sEMG and pattern recognition control within the virtual integration environment (VIE. Prosthetic training sessions then allowed participants to complete a variety of activities of daily living with the MPL. Training and Motion Control Accuracy scores quantified their ability to consistently train and execute unique muscle-to-motion contraction patterns. Each user also completed one prosthetic functional metric—the Southampton Hand Assessment Procedure (SHAP for TR01 and the Jebsen-Taylor Hand Function Test (JHFT for TR02. Haptic feedback capabilities were integrated for TR01. TR01 achieved 95% accuracy at 84% of his VIE sessions. He demonstrated improved scores over a year of prosthetic training sessions, ultimately achieving simultaneous control of 13 of the 17 (76% attempted motions. His performance on the SHAP improved from baseline to final assessment with an increase in number of tasks achieved. TR01 also used vibrotactile sensors to successfully discriminate between hard and soft objects being grasped by the MPL hand. TR02 demonstrated 95% accuracy at 79% of his VIE sessions. He demonstrated improved scores over months of prosthetic training sessions, however there was a significant drop in scores initially following a mid

  17. SPICE evaluation of the S/N ratio for Si microstrip detectors

    International Nuclear Information System (INIS)

    Candelori, A.; Paccagnella, A.; Padova Univ.; Nardi, F.

    1999-01-01

    SPICE simulations of AC-coupled single-sided Si microstrip detectors connected to the Pre-Shape 32 read-out chip have been performed in order to determine the geometrical characteristics which maximize the signal-to-noise ratio at room temperature. All the resistive and capacitive elements of the detector have been determined as a function of the ω/ρ ratio, by considering experimental and simulated data available in the literature. The SPICE model takes into account all the main noise source in the detector and read-out electronics. The minimum ionizing particle current signal shape characteristics have been introduced in the simulations. Two read-out configurations have been investigated for 6.4 cm and 12.8 cm long detectors. Finally, general guidelines in the detector design have been proposed starting from the simulation results

  18. Evaluation of FOXFET biased ac-coupled silicon strip detector prototypes for CDF SVX upgrade

    International Nuclear Information System (INIS)

    Laakso, M.

    1992-03-01

    Silicon microstrip detectors for high-precision charged particle position measurements have been used in nuclear and particle physics for years. The detectors have evolved from simple surface barrier strip detectors with metal strips to highly complicated double-sided AC-coupled junction detectors. The feature of AC-coupling the readout electrodes from the diode strips necessitates the manufacture of a separate biasing structure for the strips, which comprises a common bias line together with a means for preventing the signal from one strip from spreading to its neighbors through the bias line. The obvious solution to this is to bias the strips through individual high value resistors. These resistors can be integrated on the detector wafer by depositing a layer of resistive polycrystalline silicon and patterning it to form the individual resistors. To circumvent the extra processing step required for polysilicon resistor processing and the rather difficult tuning of the process to obtain uniform and high enough resistance values throughout the large detector area, alternative methods for strip biasing have been devised. These include the usage of electron accumulation layer resistance for N + - strips or the usage of the phenomenon known as the punch-through effect for P + - strips. In this paper we present measurement results about the operation and radiation resistance of detectors with a punch-through effect based biasing structure known as a Field OXide Field-Effect Transistor (FOXFET), and present a model describing the FOXFET behavior. The studied detectors were prototypes for detectors to be used in the CDF silicon vertex detector upgrade

  19. Evaluation of FOXFET biased ac-coupled silicon strip detector prototypes for CDF SVX upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Laakso, M. (Fermi National Accelerator Lab., Batavia, IL (United States) Research Inst. for High Energy Physics (SEFT), Helsinki (Finland))

    1992-03-01

    Silicon microstrip detectors for high-precision charged particle position measurements have been used in nuclear and particle physics for years. The detectors have evolved from simple surface barrier strip detectors with metal strips to highly complicated double-sided AC-coupled junction detectors. The feature of AC-coupling the readout electrodes from the diode strips necessitates the manufacture of a separate biasing structure for the strips, which comprises a common bias line together with a means for preventing the signal from one strip from spreading to its neighbors through the bias line. The obvious solution to this is to bias the strips through individual high value resistors. These resistors can be integrated on the detector wafer by depositing a layer of resistive polycrystalline silicon and patterning it to form the individual resistors. To circumvent the extra processing step required for polysilicon resistor processing and the rather difficult tuning of the process to obtain uniform and high enough resistance values throughout the large detector area, alternative methods for strip biasing have been devised. These include the usage of electron accumulation layer resistance for N{sup +}{minus} strips or the usage of the phenomenon known as the punch-through effect for P{sup +}{minus} strips. In this paper we present measurement results about the operation and radiation resistance of detectors with a punch-through effect based biasing structure known as a Field OXide Field-Effect Transistor (FOXFET), and present a model describing the FOXFET behavior. The studied detectors were prototypes for detectors to be used in the CDF silicon vertex detector upgrade.

  20. Domestic Preparedness Program: Evaluation of the Agilent Gas Chromatograph - Flame Photometric Detector/Mass Selective Detector (GC-FPD/MSD) System Against Chemical Warfare Agents Summary Report

    National Research Council Canada - National Science Library

    Longworth, Terri

    2003-01-01

    This report characterizes the chemical warfare agent (CWA) detection potential of the commercially available Agilent gas chromatograph-flame photometric detector/mass selective detector (GC-FPD/MSD...

  1. Initial evaluation and management of the critical burn patient.

    Science.gov (United States)

    Vivó, C; Galeiras, R; del Caz, Ma D P

    2016-01-01

    The major improvement in burn therapy is likely to focus on the early management of hemodynamic and respiratory failures in combination with an aggressive and early surgical excision and skin grafting for full-thickness burns. Immediate burn care by first care providers is important and can vastly alter outcomes, and it can significantly limit burn progression and depth. The goal of prehospital care should be to cease the burning process as well as prevent future complications and secondary injuries for burn shock. Identifying burn patients appropriate for immediate or subacute transfer is an important step in reducing morbidity and mortality. Delays in transport to Burn Unit should be minimized. The emergency management follows the principles of the Advanced Trauma Life Support Guidelines for assessment and stabilization of airway, breathing, circulation, disability, exposure and environment control. All patients with suspected inhalation injury must be removed from the enclosure as soon as possible, and immediately administer high-flow oxygen. Any patient with stridor, shortness of breath, facial burns, singed nasal hairs, cough, soot in the oral cavity, and history of being in a fire in an enclosed space should be strongly considered for early intubation. Fibroscopy may also be useful if airway damage is suspected and to assess known lung damage. Secondary evaluation following admission to the Burn Unit of a burned patient suffering a severe thermal injury includes continuation of respiratory support and management and treatment of inhalation injury, fluid resuscitation and cardiovascular stabilization, pain control and management of burn wound. Copyright © 2015 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

  2. The evaluation of dose of TSEI with TLD and diode detector of the uterine cervix cancer

    International Nuclear Information System (INIS)

    Je, Young Wan; Na, Keyung Su; Yoon, Il Kyu; Park, Heung Deuk

    2005-01-01

    To evaluate radiation dose and accuracy with TLD and diode detector when treat total skin with electron beam. Using Stanford Technique, we treated patient with Mycosis Fungoides. 6 MeV electron beam of LINAC was used and the SSD was 300 cm. Also, acrylic speller(0.8 cm) was used. The patient position was 6 types and the gantry angle was 64, 90 and 116 degree. The patient's skin dose and the output were detected 5 to 6 times with TLD and diode. The deviations of dose detected with TLD from tumor dose were CA + 6%, thigh + 8%, umbilicus + 4%, calf - 8%, vertex - 74.4%, deep axillae - 10.2%, anus and testis - 87%, sole - 86% and nails shielded with 4 mm lead + 4%. The deviations of dose detected with diode were - 4.5% ∼ + 5% at the patient center and - 1.1% ∼ + 1% at the speller. The deviation of total skin dose was + 8% ∼ - 8% and that deviation was within the acceptable range(±10%). The boost dose was irradiated for the low dose areas(vertex, anus, sole). The electron beam output detected at the sootier was stable. It is thought that the deviation of dose at patient center detected with diode was induced by detection point and patient position.

  3. Parametric curve evaluation of a phototransistor used as detector in stereotactic radiosurgery X-ray beam

    International Nuclear Information System (INIS)

    Lima, Daniela Pontes A.; Santos, Luiz Antonio P.; Santos, Walter M.; Silva Junior, Eronides F. da

    2005-01-01

    Phototransistors have been widely used as detectors for low energy X-rays. However, when they are used in high energy X-rays fields like those generated from linear accelerators (linac), there is a certain loss of sensibility to the ionizing radiation. This damage is cumulative and irreversible. Thus, a correction factor must be applied to its response, which is proportional to the integrated dose. However, it is possible to estimate the correction factor by using the V x I parametric curve of the device. The aim of this work was to develop studies to evaluate and correlate the parametric response curve of a phototransistor with its loss of sensibility after irradiation. An Agilent 4155C semiconductor parameter analyzer was used to trace the parametric curve. X-rays were generated by a 14 MV Primus-Siemens linear accelerator. The results demonstrated that there is a correlation between the integrated dose applied to the phototransistor and the parametric response of the device. Studies are under way to determine how such behavior can provide information for the dosimetric planning in stereotactic radiosurgery. (author)

  4. Optimization, evaluation and calibration of a cross-strip DOI detector

    Science.gov (United States)

    Schmidt, F. P.; Kolb, A.; Pichler, B. J.

    2018-02-01

    This study depicts the evaluation of a SiPM detector with depth of interaction (DOI) capability via a dual-sided readout that is suitable for high-resolution positron emission tomography and magnetic resonance (PET/MR) imaging. Two different 12  ×  12 pixelated LSO scintillator arrays with a crystal pitch of 1.60 mm are examined. One array is 20 mm-long with a crystal separation by the specular reflector Vikuiti enhanced specular reflector (ESR), and the other one is 18 mm-long and separated by the diffuse reflector Lumirror E60 (E60). An improvement in energy resolution from 22.6% to 15.5% for the scintillator array with the E60 reflector is achieved by taking a nonlinear light collection correction into account. The results are FWHM energy resolutions of 14.0% and 15.5%, average FWHM DOI resolutions of 2.96 mm and 1.83 mm, and FWHM coincidence resolving times of 1.09 ns and 1.48 ns for the scintillator array with the ESR and that with the E60 reflector, respectively. The measured DOI signal ratios need to be assigned to an interaction depth inside the scintillator crystal. A linear and a nonlinear method, using the intrinsic scintillator radiation from lutetium, are implemented for an easy to apply calibration and are compared to the conventional method, which exploits a setup with an externally collimated radiation beam. The deviation between the DOI functions of the linear or nonlinear method and the conventional method is determined. The resulting average of differences in DOI positions is 0.67 mm and 0.45 mm for the nonlinear calibration method for the scintillator array with the ESR and with the E60 reflector, respectively; Whereas the linear calibration method results in 0.51 mm and 0.32 mm for the scintillator array with the ESR and the E60 reflector, respectively; and is, due to its simplicity, also applicable in assembled detector systems.

  5. Evaluation of XRI-UNO CdTe detector for nuclear medical imaging

    International Nuclear Information System (INIS)

    Jambi, L.K.; Lees, J.E.; Bugby, S.L.; Alqahtani, M.S.; Tipper, S.; Perkins, A.C.

    2015-01-01

    Over the last two decades advances in semiconductor detector technology have reached the point where they are sufficiently sensitive to become an alternative to scintillators for high energy gamma ray detection for application in fields such as medical imaging. This paper assessed the Cadmium-Telluride (CdTe) XRI-UNO semiconductor detector produced by X-RAY Imatek for photon energies of interest in nuclear imaging. The XRI-UNO detector was found to have an intrinsic spatial resolution of <0.5mm and a high incident count rate capability up to at least 1680cps. The system spatial resolution, uniformity and sensitivity characteristics are also reported

  6. Evaluation of Uncertainty of IMRT QA Using 2 Dimensional Array Detector for Head and Neck Patients

    International Nuclear Information System (INIS)

    Ban, Tae Joon; Lee, Woo Suk; Kim, Dae Sup; Baek, Geum Mun; Kwak, Jung Won

    2011-01-01

    IMRT QA using 2 Dimensional array detector is carried out with condition for discrete dose distribution clinically. And it can affect uncertainty of evaluation using gamma method. We analyze gamma index variation according to grid size and suggest validate range of grid size for IMRT QA in Hospital. We performed QA using OniPro I'mRT system software version 1.7b on 10 patients (head and neck) for IMRT. The reference dose plane (grid size, 0.1 cm; location, [0, 0, 0]) from RTP was compared with the dose plane that has different grid size (0.1 cm, 0.5 cm, 1.0 cm, 2.0 cm, 4.0 cm) and different location (along Y-axis 0 cm, 0.2 cm, 0.5 cm, 1.0 cm). The gamma index variation was evaluated by observing the level of changes in Gamma pass rate, Average signal, Standard deviation for each case. The average signal for each grid size showed difference levels of 0%, -0.19%, -0.04%, -0.46%, -8.32% and the standard deviation for each grid size showed difference levels of 0%, -0.30%, 1.24%, -0.70%, -7.99%. The gamma pass rate for each grid size showed difference levels of 0%, 0.27%, -1.43%, 5.32%, 5.60%. The gamma evaluation results according to distance in grid size range of 0.1 cm to 1.0 cm showed good agreement with reference condition (grid size 0.1 cm) within 1.5% and over 5% in case of the grid size was greater than 2.0 cm. We recognize that the grid size of gamma evaluation can make errors of IMRT QA. So we have to consider uncertainty of gamma evaluation according to the grid size and apply smaller than 2 cm grid size to reduce error and increase accuracy clinically.

  7. The Usefulness of Three-Dimensional Angiography with a Flat Panel Detector of Direct Conversion Type in a Transcatheter Arterial Chemoembolization Procedure for Hepatocellular Carcinoma: Initial Experience

    International Nuclear Information System (INIS)

    Kakeda, Shingo; Korogi, Yukunori; Hatakeyama, Yoshihisa; Ohnari, Norihiro; Oda, Nobuhiro; Nishino, Kazuyoshi; Miyamoto, Wataru

    2008-01-01

    The purpose of this study was to assess the usefulness of a three-dimensional (3D) angiography system using a flat panel detector of direct conversion type in treatments with subsegmental transcatheter arterial chemoembolization (TACE) for hepatocellular carcinomas (HCCs). Thirty-six consecutive patients who underwent hepatic angiography were prospectively examined. First, two radiologists evaluated the degree of visualization of the peripheral branches of the hepatic arteries on 3D digital subtraction angiography (DSA). Then the radiologists evaluated the visualization of tumor staining and feeding arteries in 25 patients (30 HCCs) who underwent subsegmental TACE. The two radiologists who performed the TACE assessed whether the additional information provided by 3D DSA was useful for treatments. In 34 (94.4%) of 36 patients, the subsegmental branches of the hepatic arteries were sufficiently visualized. The feeding arteries of HCCs were sufficiently visualized in 28 (93%) of 30 HCCs, whereas tumor stains were sufficiently visualized in 18 (60%). Maximum intensity projection images were significantly superior to volume recording images for visualization of the tumor staining and feeding arteries of HCCs. In 27 (90%) of 30 HCCs, 3D DSA provided additional useful information for subsegmental TACE. The high-quality 3D DSA with flat panel detector angiography system provided a precise vascular road map, which was useful for performing subsegmental TACE .of HCCs

  8. Evaluation of alternative methods for coronary calcium scoring in multi-detector-row computed tomography

    International Nuclear Information System (INIS)

    Serafin, Z.; Lasek, W.; Laskowska, K.; Marzec, M.

    2005-01-01

    Determining coronary artery calcifications is one of the methods of coronary heart disease screening. However, the traditional Agatston Calcium Score (CS) shows low interexamination reproducibility. The aim of this study was to evaluate the interscan variability coefficients of calcium measures based on three modifications of the original Agatston equation. Fifty adults (37 men and 13 women; mean age 46.2 ± 9.2 years) were included in the study. Each patient was examined with two consecutive, prospectively electrocardiographically triggered, multi-detector-row CT acquisitions to detect and quantify coronary artery calcifications. CS was calculated according to the method by Agatston et al. Alternative scores were calculated using a continuous weighting factor (CS-CM), the average lesion attenuation value (CS-SA), or both (CS-CA). The mean and median interscan percent variabilities of the methods were evaluated using nonparametric analysis of variance. In the 50 patients, 1315 calcified lesions were found. The alternative scores correlated well with CS (for CS vs. CS-SA, CS-CM, and CS-CA, r = 0.990, 0.840, and 0.946, respectively, P < 0.0001). The mean and median percent variabilities did not differ significantly among the methods tested (P = 0.370). For CS, CS-SA, CS-CM, and CS-CA the mean variabilities were 13.24%, 13.36%, 16.00%, and 13.62%, respectively. Except for CS-CM, the methods showed similar distributions of variability vs. score on Bland and Altman plots. None of the tested modifications of the Agatston method brought improvement in the interscan reproducibility of coronary calcium scoring. In our opinion, a significant reduction in variability may be achieved by a standardization of image acquisition and reconstruction. (author)

  9. Assessment of applicability of portable HPGe detector with in situ object counting system based on performance evaluation of thyroid radiobioassays

    Energy Technology Data Exchange (ETDEWEB)

    Park, Min Seok; Kwon, Tae Eun; Pak, Min Jung; Park, Se Young; Ha, Wi Ho; Jin, Young Woo [National Radiation Emergency Medical Center, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2017-06-15

    Different cases exist in the measurement of thyroid radiobioassays owing to the individual characteristics of the subjects, especially the potential variation in the counting efficiency. An In situ Object Counting System (ISOCS) was developed to perform an efficiency calibration based on the Monte Carlo calculation, as an alternative to conventional calibration methods. The purpose of this study is to evaluate the applicability of ISOCS to thyroid radiobioassays by comparison with a conventional thyroid monitoring system. The efficiency calibration of a portable high-purity germanium (HPGe) detector was performed using ISOCS software. In contrast, the conventional efficiency calibration, which needed a radioactive material, was applied to a scintillator-based thyroid monitor. Four radioiodine samples that contained 125I and 131I in both aqueous solution and gel forms were measured to evaluate radioactivity in the thyroid. ANSI/HPS N13.30 performance criteria, which included the relative bias, relative precision, and root-mean-squared error, were applied to evaluate the performance of the measurement system. The portable HPGe detector could measure both radioiodines with ISOCS but the thyroid monitor could not measure 125I because of the limited energy resolution of the NaI(Tl) scintillator. The 131I results from both detectors agreed to within 5% with the certified results. Moreover, the 125I results from the portable HPGe detector agreed to within 10% with the certified results. All measurement results complied with the ANSI/HPS N13.30 performance criteria. The results of the intercomparison program indicated the feasibility of applying ISOCS software to direct thyroid radiobioassays. The portable HPGe detector with ISOCS software can provide the convenience of efficiency calibration and higher energy resolution for identifying photopeaks, compared with a conventional thyroid monitor with a NaI(Tl) scintillator. The application of ISOCS software in a radiation

  10. Design and evaluation of a SiPM-based large-area detector module for positron emission imaging

    Science.gov (United States)

    Alva-Sánchez, H.; Murrieta-Rodríguez, T.; Calva-Coraza, E.; Martínez-Dávalos, A.; Rodríguez-Villafuerte, M.

    2018-03-01

    The design and evaluation of a large-area detector module for positron emission imaging applications, is presented. The module features a SensL ArrayC-60035-64P-PCB solid state detector (8×8 array of tileable silicon photomultipliers by SensL, 7.2 mm pitch) covering a total area of 57.4×57.4 mm2. The detector module was formed using a pixelated array of 40×40 lutetium-yttrium oxyorthosilicate (LYSO) scintillator crystal elements with 1.43 mm pitch. A 7 mm thick coupling light guide was used to allow light sharing between adjacent SiPM. A 16-channel symmetric charge division (SCD) readout board was designed to multiplex the number of signals from 64 to 16 (8 columns and 8 rows) and a center-of-gravity algorithm to identify the position. Data acquisition and digitization was accomplished using a custom-made system based on FPGAs boards. Crystal maps were obtained using 18F-positron sources and Voronoi diagrams were used to correct for geometric distortions and to generate a non-uniformity correction matrix. All measurements were taken at a controlled room temperature of 22oC. The crystal maps showed minor distortion, 90% of the 1600 total crystal elements could be identified, a mean peak-to-valley ratio of 4.3 was obtained and a 10.8% mean energy resolution for 511 keV annihilation photons was determined. The performance of the detector using our own readout board was compared to that using two different commercially readout boards using the same detector module arrangement. We show that these large-area SiPM arrays, combined with a 16-channel SCD readout board, can offer high spatial resolution, excellent energy resolution and detector uniformity and thus, can be used for positron emission imaging applications.

  11. Evaluation and development of X-ray detectors for dosimetry; Evaluierung und Entwicklung von Roentgendetektoren fuer die Dosimetrie

    Energy Technology Data Exchange (ETDEWEB)

    Boehnel, Michael

    2012-03-28

    This thesis presents the development and evaluation of a new personal dosemeter, based on the technology of energy-resolving pixelated photon-counting X-ray detectors. The basis of the development is a detailed study of the Timepix detector. The main focus is on the investigation of the energy resolving properties of the Timepix detector in counting mode and in the spectroscopic time-over-threshold mode. The approach for the production of fluorescence radiation for the detector calibration, necessary for the experiments, is presented. By using Monte Carlo simulations the spectral distribution of the resulting fluorescence spectra in dependence on the fluorescence material, the used primary X-ray radiation and the arrangement of the laboratory setup is discussed. Besides the actual fluorescence lines, the simulated calibration spectra also contain the background of scattered primary X-ray photons and fluorescence radiation contributions from parts of the experimental setup. Furthermore, the simulated spectra exhibit the corrected intensity conditions of the fluorescence emissions of the K- and L-shell. These calibration spectra permit a better match of measurements and simulations than the simplified fluorescence spectra used so far. For the detector calibration in counting mode, accelerated energy calibration methods are introduced. From measuring energy deposition spectra, the energy resolution of single pixels and the energy resolution of the complete detector could be determined by the application of a global energy calibration. It was shown that the influence of the threshold dispersion broadens the energy resolution of the single pixels, depending on the given energy deposition. The resulting energy resolution of the whole pixel matrix is thereby reduced. The negative effect of the threshold dispersion can be eliminated by the application of a single-pixel calibration. The relative energy resolution of the Timepix detector operated in the counting mode can

  12. Initial clinical experience with dual-layer detector spectral CT in patients with acute intracerebral haemorrhage: A single-centre pilot study.

    Directory of Open Access Journals (Sweden)

    Soo Buem Cho

    Full Text Available The purpose of this study was to investigate the clinical feasibility of spectral analyses using dual-layer detector spectral computed tomography (CT in acute intracerebral haemorrhage (ICH.We retrospectively reviewed patients with acute ICH who underwent CT angiography on a dual-layer detector spectral CT scanner. A spectral data analysis was performed to detect contrast enhancement in or adjacent to acute ICH by using spectral image reconstructions including monoenergetic (MonoE, virtual noncontrast (VNC, and iodine overlay fusion images. We also acquired a spectral plot to assess material differentiation within lesions.Among the 30 patients, the most common cause of acute ICH was chronic hypertension (18/30, 60% followed by trauma (5/30, 16.7%, brain tumour (3/30, 10%, Moyamoya disease (2/30, 6.7%, and haemorrhagic diathesis from anticoagulation therapy (2/30, 6.7%. Of 30 patients, 13 showed suboptimal iodine suppression in the subcalvarial spaces on VNC images compared with true noncontrast images. The CT angiographic spot sign within the acute ICH was detected in four patients (4/30, 13.3%. All three tumours were metastatic and included lung cancer (n = 2 and hepatocellular carcinoma (n = 1 which showed conspicuous delineation of an enhancing tumour portion in the spectral analysis. Spectral analyses allowed the discrimination of acute haemorrhage and iodine with enhanced lesion visualization on the MonoE images obtained at lower keVs (less than 70 keV and spectral plot.Even though the image quality of VNC is perceived to be inferior, it is feasible to evaluate acute ICH in clinical settings using dual-layer detector spectral CT. The MonoE images taken at lower keVs were useful for depicting contrast enhancing lesion, and spectral plot might be helpful for material differentiation in patients with acute ICH.

  13. Initial clinical experience with dual-layer detector spectral CT in patients with acute intracerebral haemorrhage: A single-centre pilot study.

    Science.gov (United States)

    Cho, Soo Buem; Baek, Hye Jin; Ryu, Kyeong Hwa; Moon, Jin Il; Choi, Bo Hwa; Park, Sung Eun; Bae, Kyungsoo; Jeon, Kyung Nyeo; Kim, Dong Wook

    2017-01-01

    The purpose of this study was to investigate the clinical feasibility of spectral analyses using dual-layer detector spectral computed tomography (CT) in acute intracerebral haemorrhage (ICH). We retrospectively reviewed patients with acute ICH who underwent CT angiography on a dual-layer detector spectral CT scanner. A spectral data analysis was performed to detect contrast enhancement in or adjacent to acute ICH by using spectral image reconstructions including monoenergetic (MonoE), virtual noncontrast (VNC), and iodine overlay fusion images. We also acquired a spectral plot to assess material differentiation within lesions. Among the 30 patients, the most common cause of acute ICH was chronic hypertension (18/30, 60%) followed by trauma (5/30, 16.7%), brain tumour (3/30, 10%), Moyamoya disease (2/30, 6.7%), and haemorrhagic diathesis from anticoagulation therapy (2/30, 6.7%). Of 30 patients, 13 showed suboptimal iodine suppression in the subcalvarial spaces on VNC images compared with true noncontrast images. The CT angiographic spot sign within the acute ICH was detected in four patients (4/30, 13.3%). All three tumours were metastatic and included lung cancer (n = 2) and hepatocellular carcinoma (n = 1) which showed conspicuous delineation of an enhancing tumour portion in the spectral analysis. Spectral analyses allowed the discrimination of acute haemorrhage and iodine with enhanced lesion visualization on the MonoE images obtained at lower keVs (less than 70 keV) and spectral plot. Even though the image quality of VNC is perceived to be inferior, it is feasible to evaluate acute ICH in clinical settings using dual-layer detector spectral CT. The MonoE images taken at lower keVs were useful for depicting contrast enhancing lesion, and spectral plot might be helpful for material differentiation in patients with acute ICH.

  14. Preparing for Evaluation: Lessons from the Evaluability Assessment of the Teagle Foundation's College-Community Connections Initiative. Report

    Science.gov (United States)

    Black, Kristin

    2016-01-01

    Funders, policymakers, and program leaders recognize the value of high-quality evidence. To make good use of a program evaluation, initiatives must contend with a set of fundamental questions first. Some of these are about the initiative itself: What outcomes does it seek to affect? Are daily activities in line with long-term goals? Others are…

  15. 16-Detector row computed tomographic coronary angiography in patients undergoing evaluation for aortic valve replacement: comparison with catheter angiography

    International Nuclear Information System (INIS)

    Manghat, N.E.; Morgan-Hughes, G.J.; Broadley, A.J.; Undy, M.B.; Wright, D.; Marshall, A.J.; Roobottom, C.A.

    2006-01-01

    Aim: To evaluate the diagnostic accuracy of 16-detector row computed tomography (CT) in assessing haemodynamically significant coronary artery stenoses in patients under evaluation for aortic stenosis pre-aortic valve replacement. Subjects and methods: Forty consecutive patients under evaluation for severe aortic stenosis and listed for cardiac catheterization before potential aortic valve replacement underwent coronary artery calcium (CAC) scoring and retrospective electrocardiogram (ECG)-gated multi-detector row computed tomographic coronary angiography (MDCTA) using a GE Lightspeed 16-detector row CT within 1 month of invasive coronary angiography (ICA) for comparative purposes. All 13 major coronary artery segments of the American Heart Association model were evaluated for the presence of ≥50% stenosis and compared to the reference standard. Data were analysed on a segment-by-segment basis and also in 'whole patient' terms. Results: A total of 412/450 segments from 35 patients were suitable for analysis. The overall accuracy of MDCTA for detection of segments with ≥50% stenosis was high, with a sensitivity of 81.3%, specificity 95.0%, positive predictive value (PPV) 57.8%, and negative predictive value (NPV) 98.4%. On a 'whole-patient' basis, 100% (19/19) of patients with significant coronary disease were correctly identified and there were no false-negatives. Excluding patients with CAC >1000 from the analysis improved the accuracy of MDCTA to: sensitivity 90%, specificity 98.1%, PPV 60%, NPV 99.7%. Conclusion: Non-invasive 16-detector row MDCTA accurately excludes significant coronary disease in patients with severe aortic stenosis undergoing evaluation before aortic valve replacement and in whom ICA can therefore be avoided. Its segment-by-segment accuracy is improved further if CAC > 1000 is used as a gatekeeper to MDCTA

  16. Evaluation of a synthetic single-crystal diamond detector for relative dosimetry on the Leksell Gamma Knife Perfexion radiosurgery system

    Energy Technology Data Exchange (ETDEWEB)

    Mancosu, Pietro; Reggiori, Giacomo, E-mail: giacomo.reggiori@humanitas.it; Stravato, Antonella; Gaudino, Anna; Lobefalo, Francesca; Palumbo, Valentina; Tomatis, Stefano [Physics Service of Radiation Oncology Department, Clinical and Research Center, Rozzano, Milan 20098 (Italy); Navarria, Piera; Ascolese, Anna; Scorsetti, Marta [Radiation Oncology Department, Humanitas Clinical and Research Center, Rozzano, Milan 20089 (Italy); Picozzi, Piero [Neurosurgery Department, Humanitas Clinical and Research Center, Rozzano, Milan 20089 (Italy); Marinelli, Marco; Verona-Rinati, Gianluca [Dipartimento di Ingegneria Industriale, Università di Roma Tor Vergata, Roma 00133 (Italy)

    2015-09-15

    Purpose: To evaluate the new commercial PTW-60019 synthetic single-crystal microDiamond detector (PTW, Freiburg, Germany) for relative dosimetry measurements on a clinical Leksell Gamma Knife Perfexion radiosurgery system. Methods: Detector output ratios (DORs) for 4 and 8 mm beams were measured using a microDiamond (PTW-60019), a stereotactic unshielded diode [IBA stereotactic field detector (SFD)], a shielded diode (IBA photon field detector), and GafChromic EBT3 films. Both parallel and transversal acquisition directions were considered for PTW-60019 measurements. Measured DORs were compared to the new output factor reference values for Gamma Knife Perfexion (0.814 and 0.900 for 4 and 8 mm, respectively). Profiles in the three directions were also measured for the 4 mm beam to evaluate full width at half maximum (FWHM) and penumbra and to compare them with the corresponding Leksell GammaPlan profiles. Results: FWHM and penumbra for PTW-60019 differed from the calculated values by less than 0.2 and 0.3 mm, for the parallel and transversal acquisitions, respectively. GafChromic films showed FWHM and penumbra within 0.1 mm. The output ratio obtained with the PTW-60019 for the 4 mm field was 1.6% greater in transverse direction compared to the nominal value. Comparable differences up to 0.8% and 1.0% for, respectively, GafChromic films and SFD were found. Conclusions: The microDiamond PTW-60019 is a suitable detector for commissioning and routine use of Gamma Knife with good agreement of both DORs and profiles in the three directions.

  17. Evaluation of a synthetic single-crystal diamond detector for relative dosimetry on the Leksell Gamma Knife Perfexion radiosurgery system

    International Nuclear Information System (INIS)

    Mancosu, Pietro; Reggiori, Giacomo; Stravato, Antonella; Gaudino, Anna; Lobefalo, Francesca; Palumbo, Valentina; Tomatis, Stefano; Navarria, Piera; Ascolese, Anna; Scorsetti, Marta; Picozzi, Piero; Marinelli, Marco; Verona-Rinati, Gianluca

    2015-01-01

    Purpose: To evaluate the new commercial PTW-60019 synthetic single-crystal microDiamond detector (PTW, Freiburg, Germany) for relative dosimetry measurements on a clinical Leksell Gamma Knife Perfexion radiosurgery system. Methods: Detector output ratios (DORs) for 4 and 8 mm beams were measured using a microDiamond (PTW-60019), a stereotactic unshielded diode [IBA stereotactic field detector (SFD)], a shielded diode (IBA photon field detector), and GafChromic EBT3 films. Both parallel and transversal acquisition directions were considered for PTW-60019 measurements. Measured DORs were compared to the new output factor reference values for Gamma Knife Perfexion (0.814 and 0.900 for 4 and 8 mm, respectively). Profiles in the three directions were also measured for the 4 mm beam to evaluate full width at half maximum (FWHM) and penumbra and to compare them with the corresponding Leksell GammaPlan profiles. Results: FWHM and penumbra for PTW-60019 differed from the calculated values by less than 0.2 and 0.3 mm, for the parallel and transversal acquisitions, respectively. GafChromic films showed FWHM and penumbra within 0.1 mm. The output ratio obtained with the PTW-60019 for the 4 mm field was 1.6% greater in transverse direction compared to the nominal value. Comparable differences up to 0.8% and 1.0% for, respectively, GafChromic films and SFD were found. Conclusions: The microDiamond PTW-60019 is a suitable detector for commissioning and routine use of Gamma Knife with good agreement of both DORs and profiles in the three directions

  18. A Plan for the Evaluation of California's Class Size Reduction Initiative.

    Science.gov (United States)

    Kirst, Michael; Bomstedt, George; Stecher, Brian

    In July 1996, California began its Class Size Reduction (CSR) Initiative. To gauge the effectiveness of this initiative, an analysis of its objectives and an overview of proposed strategies for evaluating CSR are presented here. An outline of the major challenges that stand between CSR and its mission are provided. These include logistical…

  19. Using low energy x-ray radiography to evaluate root initiation and growth of Populus

    Science.gov (United States)

    Ronald S., Jr. Zalesny; A. L. Friend; B. Kodrzycki; D.W. McDonald; R. Michaels; A.H. Wiese; J.W. Powers

    2007-01-01

    Populus roots have been studied less than aboveground tissues. However, there is an overwhelming need to evaluate root initiation and growth in order to understand the genetics and physiology of rooting, along with genotype x environment interactions.

  20. Integrated corridor management initiative : demonstration phase evaluation, San Diego air quality test plan.

    Science.gov (United States)

    2012-08-01

    This report presents the test plan for conducting the Air Quality Analysis for the United States Department of Transportation (U.S. DOT) evaluation of the San Diego Integrated Corridor Management (ICM) Initiative Demonstration. The ICM projects being...

  1. Integrated corridor management initiative : demonstration phase evaluation, Dallas air quality test plan.

    Science.gov (United States)

    2012-08-01

    This report presents the test plan for conducting the Air Quality Analysis for the United States : Department of Transportation (U.S. DOT) evaluation of the Dallas U.S. 75 Integrated Corridor : Management (ICM) Initiative Demonstration. The ICM proje...

  2. Integrated corridor management initiative : demonstration phase evaluation - Dallas technical capability analysis test plan.

    Science.gov (United States)

    This report presents the test plan for conducting the Technical Capability Analysis for the United States : Department of Transportation (U.S. DOT) evaluation of the Dallas U.S. 75 Integrated Corridor : Management (ICM) Initiative Demonstration. The ...

  3. Integrated corridor management initiative : demonstration phase evaluation, San Diego technical capability analysis test plan.

    Science.gov (United States)

    2012-08-01

    This report presents the test plan for conducting the Technical Capability Analysis for the United States Department of Transportation (U.S. DOT) evaluation of the San Diego Integrated Corridor Management (ICM) Initiative Demonstration. The ICM proje...

  4. TH-CD-201-12: Preliminary Evaluation of Organic Field Effect Transistors as Radiation Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Syme, A [Nova Scotia Cancer Centre, Halifax, Nova Scotia (Canada); Lin, H; Rubio-Sanchez, J; Perepichka, D [McGill University, Montreal, QC (Canada)

    2016-06-15

    Purpose: To fabricate organic field effect transistors (OFETs) and evaluate their performance before and after exposure to ionizing radiation. To determine if OFETs have potential to function as radiation dosimeters. Methods: OFETs were fabricated on both Si/SiO{sub 2} wafers and flexible polymer substrates using standard processing techniques. Pentacene was used as the organic semiconductor material and the devices were fabricated in a bottom gate configuration. Devices were irradiated using an orthovoltage treatment unit (120 kVp x-rays). Threshold voltage values were measured with the devices in saturation mode and quantified as a function of cumulative dose. Current-voltage characteristics of the devices were measured using a Keithley 2614 SourceMeter SMU Instrument. The devices were connected to the reader but unpowered during irradiations. Results: Devices fabricated on Si/SiO2 wafers demonstrated excellent linearity (R{sup 2} > 0.997) with threshold voltages that ranged between 15 and 36 V. Devices fabricated on a flexible polymer substrate had substantially smaller threshold voltages (∼ 4 – 8 V) and slightly worse linearity (R{sup 2} > 0.98). The devices demonstrated excellent stability in I–V characteristics over a large number (>2000) cycles. Conclusion: OFETs have demonstrated excellent potential in radiation dosimetry applications. A key advantage of these devices is their composition, which can be substantially more tissue-equivalent at low photon energies relative to many other types of radiation detector. In addition, fabrication of organic electronics can employ techniques that are faster, simpler and cheaper than conventional silicon-based devices. These results support further development of organic electronic devices for radiation detection purposes. Funding Support, Disclosures, and Conflict of Interest: This work was funded by the Natural Sciences and Engineering Research Council of Canada.

  5. Radiation detectors

    International Nuclear Information System (INIS)

    2013-01-01

    This sixth chapter presents the operational principles of the radiation detectors; detection using photographic emulsions; thermoluminescent detectors; gas detectors; scintillation detectors; liquid scintillation detectors; detectors using semiconductor materials; calibration of detectors; Bragg-Gray theory; measurement chain and uncertainties associated to measurements

  6. Evaluation of the influence of parameters that determine the mean glandular dose in mammography using different detectors

    International Nuclear Information System (INIS)

    Costa, K.; Nogueira, M. S.

    2015-10-01

    Full text: Mammography is a test used for early detection of breast cancer. The mean glandular dose (MGD) is dosimetric greatness accepted as indicative of carcinogenic risk induced by ionizing radiation in the breasts of women undergoing mammography exams. MGD value is estimated from the incident air kerma (k i), associated with conversion factors which depend on the half-value layer (HVL), the breast composition and thickness compressed breast. This study aims to evaluate the influence of the parameters used to determine the MGD using different measurement detectors. Measurements were performed on a Siemens Mammomat Model 300 Nova mammography equipment; this has the combinations Anode/Filter of Mo/Mo, Mo/Rh and W/Rh. Detectors used were the ionization chamber Model 10X6-6M manufactured by Radcal Co., two solid-state detectors, one Model AGMS-M manufactured by Radcal Co. and other Model Xi Mammo manufactured by UNFORS. The detectors measures were compared and the MGD value was estimated; differences between measurements and the reference values were higher in HVL and k i parameters. The results are displayed according to other published works. (Author)

  7. Evaluation of the detector response function digital conventional radiology; Evaluacion de la funcion de respuesta del detector degital en radiologia convencional. Obtencion de la funcion de referencia

    Energy Technology Data Exchange (ETDEWEB)

    Arino Gil, A.; Hernandez Rodriguez, J.; Mateos Salvador, P.; Rodriguez Lopez, B.; Font Gelabert, J. C.

    2013-07-01

    The objective of this work is to obtain the response function that relates the air kerma at the entrance of the detector and pixel value, for a series of digital detectors of conventional Radiology model Optimus DigitalDiagnost Philips () and 6000 Definium General Electric. From the set of measurements is obtained a response function for each reference type of detector, and compared with those published in the literature for these teams. (Author)

  8. Evaluating the output stability of LINAC with a reference detector using 3D water phantom

    International Nuclear Information System (INIS)

    Shimozato, Tomohiro; Kojima, Tomo; Sakamoto, Masataka; Hata, Yuji; Sasaki, Koji; Araki, Noriyuki

    2013-01-01

    We report the discovery of abnormal fluctuations in the output obtained when measuring a water phantom and adjustments that reduce these outliers. Using a newly developed three-dimensional scanning water phantom system, we obtained the depth dose and off-axis dose ratio required for the beam data of a medical linear accelerator (LINAC). The field and reference detectors were set such that the measured values could be viewed in real time. We confirmed the scanning data using the field detector and the change in the output using the reference detector while measuring by using the water phantom. Prior to output adjustment of the LINAC, we observed output abnormalities as high as 18.4%. With optimization of accelerator conditions, the average of the output fluctuation width was reduced to less than ±0.5%. Through real-time graphing of reference detector measurements during measurement of field detector, we were able to rapidly identify abnormal fluctuations. Although beam data collected during radiation treatment planning are corrected for output fluctuations, it is possible that sudden abnormal fluctuations actually occur in the output. Therefore, the equipment should be tested for output fluctuations at least once a year. Even after minimization of fluctuations, we recommend determining the potential dose administered to the human body taking into account the width of the output fluctuation. (author)

  9. SPICE evaluation of the S/N ratio for Si microstrip detectors

    International Nuclear Information System (INIS)

    Candelori, A.; Paccagnella, A.; Nardi, F.; Bacchetta, N.; Bisello, D.

    1999-01-01

    SPICE simulations of ac-coupled single-sided Si microstrip detectors connected to the PreShape 32 read-out chip have been performed in order to determine the geometrical characteristics (i.e., the strip pitch p and width w) which maximize the signal-to-noise ratio. All of the resistive and capacitive elements of the detector have been determined as a function of the w/p ratio by considering experimental and simulated data available in literature. The SPICE model the authors propose in this work takes into account all the main noise sources in the detector and read-out electronics. The minimum ionizing particle current signal shape has been introduced in the simulations. Two read-out configurations (every strip or every second strip) have been investigated for 6.4- and 12.8-cm-long detectors. The equivalent noise charge as determined by the simulations has been compared with analytical calculations, in order to determine the limits and the corrections to a simplified analytical noise model. Finally, general guidelines for the detector design have been proposed, based on the simulation results

  10. Evaluation of B10Plus+* proportional detectors for neutron coincidence counting

    Energy Technology Data Exchange (ETDEWEB)

    Beddingfield, David H.; Yoon, Seokryung [International Atomic Energy Agency, Vienna International Centre, PO Box 100, 1400 Vienna, (Austria)

    2015-07-01

    GE-Reuter-Stokes (GERS) has developed a new line of neutron proportional counters, the B10Plus+* proportional counter. The detector design is intended to serve as a cost-effective alternative to traditional {sup 3}He proportional counters in a variety of applications. The detector is a hybrid design 10B-lined tube optimized with the addition of a small quantity of 3He gas to improve the detector performance and efficiency. As a demonstration of the B10Plus+* detector, GERS has constructed a Uranium Neutron Collar (UNCL) system consisting of B-10Plus+* proportional counters. GERS has designed and built a demonstration UNCL system intended to match the performance of a Type-I UNCL design in Pressurized Water Reactor (PWR) geometry operating in thermal mode. GERS offered their system on loan to the International Atomic Energy Agency (IAEA) Safeguards Division of Technical and Scientific Services for an assessment of the detector technology and the demonstration system. We have characterized the demonstration UNCL system and compared its performance with a traditional Type-I UNCL design in regular use by the IAEA. This paper summarizes our findings and observations during the characterization and testing activity. (authors)

  11. Performance evaluation of a lossy transmission lines based diode detector at cryogenic temperature.

    Science.gov (United States)

    Villa, E; Aja, B; de la Fuente, L; Artal, E

    2016-01-01

    This work is focused on the design, fabrication, and performance analysis of a square-law Schottky diode detector based on lossy transmission lines working under cryogenic temperature (15 K). The design analysis of a microwave detector, based on a planar gallium-arsenide low effective Schottky barrier height diode, is reported, which is aimed for achieving large input return loss as well as flat sensitivity versus frequency. The designed circuit demonstrates good sensitivity, as well as a good return loss in a wide bandwidth at Ka-band, at both room (300 K) and cryogenic (15 K) temperatures. A good sensitivity of 1000 mV/mW and input return loss better than 12 dB have been achieved when it works as a zero-bias Schottky diode detector at room temperature, increasing the sensitivity up to a minimum of 2200 mV/mW, with the need of a DC bias current, at cryogenic temperature.

  12. Instrumental basis utilizing a sodium iodide detector for radioactive soil evaluations for site remediation

    International Nuclear Information System (INIS)

    Davis, A.I.

    1996-07-01

    This document provides the design rational for using a 5.08 by 5.08 cm (2 by 2 in.) sodium iodide detector to aid in boundary mapping of the radioactive contaminated soils at the Hanford Site. The detector can provide adequate response to a homogeneously contaminated soil volume of at least 1.22 to 1.52 m in diameter and up to 45.7 cm deep. The gamma activity basis is described by a soil column in a right circular cylinder that is uniformly isotopic. The detection techniques and characteristics are used to define contaminated areas requiring excavation by locating regions where gamma activities exceed cleanup standards. To determine the areas and boundary of contamination, the boundary and adjacent surfaces will be mapped using the detector operated in a windowed gross-gamma mode

  13. Evaluation of a hybrid photon counting pixel detector for X-ray polarimetry

    International Nuclear Information System (INIS)

    Michel, T.; Durst, J.

    2008-01-01

    It has already been shown in literature that X-ray sensitive CCDs can be used to measure the degree of linear polarization of X-rays using the effect that photoelectrons are emitted with a non-isotropic angular distribution in respect to the orientation of the electric field vector of impinging photons. Up to now hybrid semiconductor pixel detectors like the Timepix-detector have never been used for X-ray polarimetry. The main reason for this is that the pixel pitch is large compared to CCDs which results in a much smaller analyzing power. On the other hand, the active thickness of the sensor layer can be larger than in CCDs leading to an increased efficiency. Therefore hybrid photon counting pixel detectors may be used for imaging and polarimetry at higher photon energies. For irradiation with polarized X-ray photons we were able to measure an asymmetry between vertical and horizontal double hit events in neighboring pixels of the hybrid photon counting Timepix-detector at room temperature. For the specific spectrum used in our experiment an average polarization asymmetry of (0.96±0.02)% was measured. Additionally, the Timepix-detector with its spectroscopic time-over-threshold-mode was used to measure the dependence of the polarization asymmetry on energy deposition in the detector. Polarization asymmetries between 0.2% at 29 keV and 3.4% at 78 keV energy deposition were determined. The results can be reproduced with our EGS4-based Monte-Carlo simulation

  14. SU-F-T-473: Evaluation of Off-Axis And Peripheral Dose Using Different Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Ganesan, B; Prakasarao, A; Singaravelu, G [Anna University, Chennai, TamilNadu (India); Palraj, T; Rai, R [Dr. Rai Memorial Cancer Institute, Chennai, TamilNadu (India)

    2016-06-15

    Purpose: In radiation therapy, measurement of off-axis and peripheral dose is a tedious task. The dose distribution along the beam central axis give only part of the information required for an accurate dose description inside the patient. Dose distributions in 2-D and 3-D are determined with central axis data in conjunction with off-axis dose profiles. Combining a central axis dose distribution with off-axis data results in volume dose matrix that provides 2-D and 3-D information on dose distribution. By considering the importance of these two parameters this study investigates and compares the off axis and peripheral dose measurement using Ionization chamber, MOSFET, Radiochromic film and EDR2 film. Methods: In the measurement of off-axis and peripheral doses 0.6cc farmer type chamber, EDR-2 film, MD-55 radiochromic film and MOSFET detectors were used for both 6MV and 15MV beams. The off-axis and peripheral dose was measured at every 1 cm interval by changing the position of the couch without disturbing the other experimental setup in particular, the phantom with detector position. Results: Readings were obtained for both 6MV and 15MV photon beams at SSD technique for various field size using MOSFET, Ionization chamber and Radiochromic film. The results shows the percentage difference between various detectors for various field sizes. For Peripheral dose measurement were taken from the edge of the field size and for off axis it is measured form central axis dose. Conclusion: In conclusion, our study shows that no detector is ideal and only a comparison between different detectors highlights the weaknesses of each detector. MOSFET provides adequate dose assessment in off-axis and peripheral regions in 6MV and 15MV photon beams. Film dosimetry in general a convenient method to generate one- and two-dimensional dose distributions. The result of this indicates that MOSFET is flexible tool for relative dosimetry as films.

  15. Ion beam evaluation of silicon carbide membrane structures intended for particle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Pallon, J., E-mail: jan.pallon@nuclear.lu.se [Division of Nuclear Physics, Physics Department, Lund University, Box 118, SE-221 00 Lund (Sweden); Syväjärvi, M. [Linköping University, Department of Physics, Chemistry and Biology, SE-58183 Linköping (Sweden); Graphensic AB, Teknikringen 1F, SE-58330 Linköping (Sweden); Wang, Q. [Sensor System, ACREO Swedish ICT AB, Box 1070, SE-164 25 Kista (Sweden); Yakimova, R.; Iakimov, T. [Linköping University, Department of Physics, Chemistry and Biology, SE-58183 Linköping (Sweden); Graphensic AB, Teknikringen 1F, SE-58330 Linköping (Sweden); Elfman, M.; Kristiansson, P.; Nilsson, E.J.C.; Ros, L. [Division of Nuclear Physics, Physics Department, Lund University, Box 118, SE-221 00 Lund (Sweden)

    2016-03-15

    Thin ion transmission detectors can be used as a part of a telescope detector for mass and energy identification but also as a pre-cell detector in a microbeam system for studies of biological effects from single ion hits on individual living cells. We investigated a structure of graphene on silicon carbide (SiC) with the purpose to explore a thin transmission detector with a very low noise level and having mechanical strength to act as a vacuum window. In order to reach very deep cavities in the SiC wafers for the preparation of the membrane in the detector, we have studied the Inductive Coupled Plasma technique to etch deep circular cavities in 325 μm prototype samples. By a special high temperature process the outermost layers of the etched SiC wafers were converted into a highly conductive graphitic layer. The produced cavities were characterized by electron microscopy, optical microscopy and proton energy loss measurements. The average membrane thickness was found to be less than 40 μm, however, with a slightly curved profile. Small spots representing much thinner membrane were also observed and might have an origin in crystal defects or impurities. Proton energy loss measurement (also called Scanning Transmission Ion Microscopy, STIM) is a well suited technique for this thickness range. This work presents the first steps of fabricating a membrane structure of SiC and graphene which may be an attractive approach as a detector due to the combined properties of SiC and graphene in a monolithic materials structure.

  16. Evaluation of neutron shielding properties of lead glass using bubble detector

    International Nuclear Information System (INIS)

    Viswanathan, S.; Vishwa Prasad, K.; Srinivasan, T.K.; Ponraju, D.

    1999-01-01

    Neutron shielding properties of lead glass had been studied using a 241 Am-Be neutron source. Indigenously developed bubble detector was used as neutron detector. Attenuation curves were determined experimentally for the lead glass under the conditions of broad beam geometry. Theoretical calculations were made using Monte Carlo code MCNP3. Measurements were made for polyethylene and concrete to serve as reference. The measured and calculated neutron removal cross sections of lead glass, polyethylene and concrete are reported in this paper. Good agreement is observed between the experimental results and theoretical calculations. (author)

  17. Containment performance evaluation for the GESSAR-II plant for seismic initiating events

    International Nuclear Information System (INIS)

    Shiu, K.K.; Chu, T.; Ludewig, H.; Pratt, W.T.

    1986-01-01

    As a part of the overall effort undertaken by Brookhaven National Laboratory (BNL) to review the GESSAR-II probabilistic risk assessment, an independent containment performance evaluation was performed using the containment event tree approach. This evaluation focused principally on those accident sequences which are initiated by seismic events. This paper reports the findings of this study. 1 ref

  18. Evaluation of a GEM and CAT-based detector for radiation therapy beam monitoring

    International Nuclear Information System (INIS)

    Brahme, A.; Danielsson, M.; Iacobaeus, C.; Ostling, J.; Peskov, V.; Wallmark, M.

    2000-01-01

    We are developing a radiation therapy beam monitor for the Karolinska Institute. This monitor will consist of two consecutive detectors confined in one gas chamber: a 'keV-photon detector', which will allow diagnostic quality visualization of the patient, and a 'MeV-photon detector', that will measure the absolute intensity of the therapy beam and its position with respect to the patient. Both detectors are based on highly radiation resistant gas and solid photon to electron converters, combined with GEMs and a CAT as amplification structures. We have performed systematic studies of the high-rate characteristics of the GEM and the CAT, as well as tested the electron transfer through these electron multipliers and various types of converters. The tests show that the GEM and the CAT satisfy all requirements for the beam monitoring system. As a result of these studies we successfully developed and tested a full section of the beam monitor equipped with a MeV-photon converter placed between the GEM and the CAT

  19. Evaluation and selection of optical feedback preamplifiers first cooled state for silicon-lithium detector

    International Nuclear Information System (INIS)

    Diaz Garcia, A.; Cabal Rodriguez, A.E.; Suarez Canner, E.

    1996-01-01

    The paper describes the principal characteristics of field-effect transistors and light-emitter diodes that allow to obtain a good energy resolution in Si Li detectors for X ray fluorescence manufactured at CEADEN. There exhibited transconductance values dl/dV and gate current for 16 researched field-effect transistor as well as the measurement circuits

  20. Evaluating State-of-the-art Object Detector on Challenging Traffic Light Data

    DEFF Research Database (Denmark)

    Jensen, Morten Bornø; Nasrollahi, Kamal; Moeslund, Thomas B.

    2017-01-01

    -of-the-art, real-time object detection system You Only Look Once, (YOLO) on the public LISA Traffic Light dataset available through the VIVA-challenge, which contain a high number of annotated traffic lights, captured in varying light and weather conditions. The YOLO object detector achieves an AUC of impres...

  1. Evaluation of the radiation field in the future circular collider detector

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00211473; Cerutti, Francesco; Ferrari, Alfredo; Riegler, Werner; Vlachoudis, Vasilis; CERN. Geneva. ATS Department

    2016-01-01

    The radiation load on a detector at a 100 TeV proton-proton collider, that is being investigated within the Future Circular Collider (FCC) study, is presented. A peak luminosity of 30 1034 cm−2s−1 and a total integrated luminosity of 30 ab−1 are assumed for these radiation studies. A first concept of the detector foresees the presence of central and forward sub-detectors that provide acceptance up to |η|=6 inside a magnetic field generated by the combination of a central solenoid and two forward dipoles. This layout has been modelled and relevant fluence and dose distributions have been calculated using the FLUKA Monte Carlo code. Distributions of fluence rates are discussed separately for charged particles, neutrons and pho- tons. Dose and 1 MeV neutron equivalent fluence, for the accumulated integrated luminosity, are presented. The peak values of these quantities in the different sub-detectors are highlighted, in order to define the radiation tolerance requirements for the choice of possible technol...

  2. A performance evaluation study of three types of alpha-track detector radon monitors

    International Nuclear Information System (INIS)

    Yeager, W.M.; Lucas, R.M.; Daum, K.A.; Sensintaffar, E.; Poppell, S.; Feldt, L.; Clarkin, M.

    1991-01-01

    Three models of alpha-track detector (ATD) Rn monitors were exposed in Environmental Protection Agency (EPA) Rn chambers to obtain estimates of precision and bias for the National Residential Radon Survey (NRRS). Exposures in this study ranged from 37 to 740 Bq y m-3 (1 to 20 pCi y L-1), plus blanks. These exposures correspond to the range expected in most U.S. residences. All detectors were purchased through a Rn mitigation firm to assure that the vendors did not give special attention to the ATDs used in this study. Ten ATDs of each model were studied at 12 exposures. The mean and standard deviation of the reported values for each model were calculated and compared with the continuously monitored chamber concentrations to determine the bias and precision at each exposure. Results of this analysis were discussed with the vendors, who took corrective actions. Changes in track counting procedures and calibrations improved detector performance. Readings of one detector were adjusted based on a regression of the monitored values on the reported values

  3. Evaluation of light detector surface area for functional Near Infrared Spectroscopy.

    Science.gov (United States)

    Wang, Lei; Ayaz, Hasan; Izzetoglu, Meltem; Onaral, Banu

    2017-10-01

    Functional Near Infrared Spectroscopy (fNIRS) is an emerging neuroimaging technique that utilizes near infrared light to detect cortical concentration changes of oxy-hemoglobin and deoxy-hemoglobin non-invasively. Using light sources and detectors over the scalp, multi-wavelength light intensities are recorded as time series and converted to concentration changes of hemoglobin via modified Beer-Lambert law. Here, we describe a potential source for systematic error in the calculation of hemoglobin changes and light intensity measurements. Previous system characterization and analysis studies looked into various fNIRS parameters such as type of light source, number and selection of wavelengths, distance between light source and detector. In this study, we have analyzed the contribution of light detector surface area to the overall outcome. Results from Monte Carlo based digital phantoms indicated that selection of detector area is a critical system parameter in minimizing the error in concentration calculations. The findings here can guide the design of future fNIRS sensors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Evaluation of the x-ray response of a position-sensitive microstrip detector with an integrated readout chip

    International Nuclear Information System (INIS)

    Rossington, C.; Jaklevic, J.; Haber, C.; Spieler, H.; Reid, J.

    1990-08-01

    The performance of an SVX silicon microstrip detector and its compatible integrated readout chip have been evaluated in response to Rh Kα x-rays (average energy 20.5 keV). The energy and spatial discrimination capabilities, efficient data management and fast readout rates make it an attractive alternative to the CCD and PDA detectors now being offered for x-ray position sensitive diffraction and EXAFS work. The SVX system was designed for high energy physics applications and thus further development of the existing system is required to optimize it for use in practical x-ray experiments. For optimum energy resolution the system noise must be decreased to its previously demonstrated low levels of 2 keV FWHM at 60 keV or less, and the data handling rate of the computer must be increased. New readout chips are now available that offer the potential of better performance. 15 refs., 7 figs

  5. Coronary computed tomography angiography with 320-row detector and using the AIDR-3D: initial experience; Angiotomografia computadorizada de coronarias com tomografo com 320 fileiras de detectores e utilizando o AIDR-3D: experiencia inicial

    Energy Technology Data Exchange (ETDEWEB)

    Sasdelli Neto, Roberto; Nomura, Cesar Higa; Macedo, Ana Carolina Sandoval; Bianco, Danilo Perussi; Kay, Fernando Uliana; Szarf, Gilberto; Teles, Gustavo Borges da Silva; Shoji, Hamilton; Santana Netto, Pedro Vieira; Passos, Rodrigo Bastos Duarte; Chate, Rodrigo Caruso; Ishikawa, Walther Yoshiharu; Lima, Joao Paulo Bacellar Costa; Rocha, Marcelo Assis; Marcos, Vinicius Neves; Funari, Marcelo Buarque de Gusmao, E-mail: roberto.neto@einstein.br [Hospital Israelita Albert Einstein, Sao Paulo, SP (Brazil); Failla, Bruna Bonaventura [Universidade Metodista de Sao Paulo, Sao Bernardo do Campo, SP (Brazil)

    2013-07-01

    Coronary computed tomography angiography (coronary CTA) is a powerful non-invasive imaging method to evaluate coronary artery disease. Nowadays, coronary CTA estimated effective radiation dose can be dramatically reduced using state-of-the-art scanners, such as 320-row detector CT (320-CT), without changing coronary CTA diagnostic accuracy. To optimize and further reduce the radiation dose, new iterative reconstruction algorithms were released recently by several CT manufacturers, and now they are used routinely in coronary CTA. This paper presents our first experience using coronary CTA with 320-CT and the Adaptive Iterative Dose Reduction 3D (AIDR-3D). In addition, we describe the current indications for coronary CTA in our practice as well as the acquisition standard protocols and protocols related to CT application for radiation dose reduction. In conclusion, coronary CTA radiation dose can be dramatically reduced following the 'as low as reasonable achievable' principle by combination of exam indication and well-documented technics for radiation dose reduction, such as beta blockers, low-kV, and also the newest iterative dose reduction software as AIDR-3D. (author)

  6. Characteristic performance evaluation of a photon counting Si strip detector for low dose spectral breast CT imaging

    Science.gov (United States)

    Cho, Hyo-Min; Barber, William C.; Ding, Huanjun; Iwanczyk, Jan S.; Molloi, Sabee

    2014-01-01

    Purpose: The possible clinical applications which can be performed using a newly developed detector depend on the detector's characteristic performance in a number of metrics including the dynamic range, resolution, uniformity, and stability. The authors have evaluated a prototype energy resolved fast photon counting x-ray detector based on a silicon (Si) strip sensor used in an edge-on geometry with an application specific integrated circuit to record the number of x-rays and their energies at high flux and fast frame rates. The investigated detector was integrated with a dedicated breast spectral computed tomography (CT) system to make use of the detector's high spatial and energy resolution and low noise performance under conditions suitable for clinical breast imaging. The aim of this article is to investigate the intrinsic characteristics of the detector, in terms of maximum output count rate, spatial and energy resolution, and noise performance of the imaging system. Methods: The maximum output count rate was obtained with a 50 W x-ray tube with a maximum continuous output of 50 kVp at 1.0 mA. A109Cd source, with a characteristic x-ray peak at 22 keV from Ag, was used to measure the energy resolution of the detector. The axial plane modulation transfer function (MTF) was measured using a 67 μm diameter tungsten wire. The two-dimensional (2D) noise power spectrum (NPS) was measured using flat field images and noise equivalent quanta (NEQ) were calculated using the MTF and NPS results. The image quality parameters were studied as a function of various radiation doses and reconstruction filters. The one-dimensional (1D) NPS was used to investigate the effect of electronic noise elimination by varying the minimum energy threshold. Results: A maximum output count rate of 100 million counts per second per square millimeter (cps/mm2) has been obtained (1 million cps per 100 × 100 μm pixel). The electrical noise floor was less than 4 keV. The energy resolution

  7. Evaluation of detectors for blood bioanalysis in Lu-177 and I-131 therapies for bone marrow dosimetry; Avaliacao de detectores para bioanalise de sangue em terapias com Lu-177 and I-131 para dosimetria de medula ossea

    Energy Technology Data Exchange (ETDEWEB)

    Degenhardt, Amilie Louize

    2016-10-01

    The measures traceability is mandatory for minimizing uncertainties in internal dosimetry for radiopharmaceuticals clinical studies and ensures the quality of the standard. Equipment should have resolution and efficiency compatible with radionuclides energies and, additionally, be able to quantify variations in human bodies' activities samples since the initial administration near the minimum residual activities. For testing three equipment (ionization chamber Capintec 25R, sodium iodine scintillator LTI Genesys Gamma-1 and high hyperpure germanium detector Canberra), they were prepared Lu-177 and I-131 radiation sources simulating patient's blood samples activities by adopting the following hypothesis: (1) initial activities according the Brazilian protocols; (2) blood volume in the whole body (5.3 L for adult men and 1.4 L for 5 years-old children); (3) effective half-lives (1.61 h and 42.9 h for Lu-177 bi-exponential adjustment and 15.7 h for I-131 mono-exponential adjustment); (4) sampling between 30 min and 168 h; (v) blood density adjustments. The standard sources were measured in the secondary standard ionization chamber Centronics IG11 at the Laboratorio Nacional de Metrologia das Radiacoes Ionizantes. The Capintec ionization chamber efficiencies ranged, respectively for I-131 and Lu-177, between (111.58±0.02)% and (102.27±0.01)% and HPGe semiconductor detector efficiencies ranged, respectively, between (89.40±0.03)% and (87.80±0.04)%. For the NaI detector, when the Lu-177 sources were positioned inside the detector the efficiencies ranged between (12.66±0.01)% and (11.54± 0.07)% and when the sources were positioned at 5 cm and 10 cm from the detector the efficiencies decreased to less than 5%. For I-131 sources positioned inside the detector, the efficiencies ranged between (29.76±0.21)% and (30.20±0.04)% and they decreased to less than 5% when they were positioned at 5 cm and 10 cm from the detector (deviation greater than 95

  8. Evaluation study between the chemical and electrochemical etching for solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Ramos, S.; Espinosa, G.; Golzarri, J.I.

    1991-01-01

    Since there are several methods of etching in the solid state nuclear track detectors (SSNTD) it is necessary to know which gives the best results for a specific problem. The purpose of this work is to analyze and compare both the chemical etching and the electrochemical etching. The SSNTD has a preferential response to certain kinds of particles and energies, according to the material used as detector. On the other hand the efficiency is a function of the incidence angle of the radiation and some other parameters such as temperature, concentration and type of solvent used in the etching process, and the method used for the etching. Therefore, it is necessary to extend as much as possible our knowledge of such parameters in order to choose the more efficient one for a specific problem

  9. Evaluation of new 5 inch photomultiplier for use in threshold Cherenkov detectors with aerogel radiator

    International Nuclear Information System (INIS)

    Wojtsekhowski, B.; Zorn, C.; Flyckt, S.O.

    2000-01-01

    A cost effective alternative to UV-sensitive 5 inch PMTs often used with threshold Aerogel Cherenkov detectors has been developed and tested. The photomultiplier -XP4572-is a variation of the Photonis XP4512 glass window tube with improved electron collection efficiency. Fast timing and high gain were only moderately compromised. The effective quantum efficiency has been measured as twice that of a Burle 8854 Quantacon when exposed to a Cherenkov spectrum generated by Ru-106 electrons (les;3.54 MeV) through 1 cm of high index, high transparency Matsushita Electric aerogel (n=1.05). This new phototube is being installed in an aerogel-based Cherenkov detector for Hall A at Jefferson Lab

  10. A novel radiation detector for removing scattered radiation in chest radiography: Monte Carlo simulation-based performance evaluation

    Science.gov (United States)

    Roh, Y. H.; Yoon, Y.; Kim, K.; Kim, J.; Kim, J.; Morishita, J.

    2016-10-01

    Scattered radiation is the main reason for the degradation of image quality and the increased patient exposure dose in diagnostic radiology. In an effort to reduce scattered radiation, a novel structure of an indirect flat panel detector has been proposed. In this study, a performance evaluation of the novel system in terms of image contrast as well as an estimation of the number of photons incident on the detector and the grid exposure factor were conducted using Monte Carlo simulations. The image contrast of the proposed system was superior to that of the no-grid system but slightly inferior to that of the parallel-grid system. The number of photons incident on the detector and the grid exposure factor of the novel system were higher than those of the parallel-grid system but lower than those of the no-grid system. The proposed system exhibited the potential for reduced exposure dose without image quality degradation; additionally, can be further improved by a structural optimization considering the manufacturer's specifications of its lead contents.

  11. Evaluation of the charge-sharing effects on spot intensity in XRD setup using photon-counting pixel detectors

    International Nuclear Information System (INIS)

    Nilsson, H.-E.; Mattsson, C.G.; Norlin, B.; Froejdh, C.; Bethke, K.; Vries, R. de

    2006-01-01

    In this study, we examine how charge loss due to charge sharing in photon-counting pixels detectors affects the recording of spot intensity in an X-ray diffraction (XRD) setup. In the photon-counting configuration, the charge from photons that are absorbed at the boarder of a pixel will be shared between two pixels. If the threshold is high enough, these photons will not be counted whereas if it is low enough, they will be counted twice. In an XRD setup, the intensity and position of various spots should be recorded. Thus, the intensity measure will be affected by the setting of the threshold. In this study, we used a system level Monte Carlo simulator to evaluate the variations in the intensity signals for different threshold settings and spot sizes. The simulated setup included an 8keV mono-chromatic source (providing a Gaussian shaped spot) and the MEDIPIX2 photon-counting pixel detector (55 μm x 55 μm pixel size with 300μm silicon) at various detector biases. Our study shows that the charge-sharing distortion can be compensated by numerical post processing and that high resolution in both charge distribution and position can be achieved

  12. Development and performance evaluation of an experimental fine pitch detector multislice CT scanner.

    Science.gov (United States)

    Imai, Yasuhiro; Nukui, Masatake; Ishihara, Yotaro; Fujishige, Takashi; Ogata, Kentaro; Moritake, Masahiro; Kurochi, Haruo; Ogata, Tsuyoshi; Yahata, Mitsuru; Tang, Xiangyang

    2009-04-01

    The authors have developed an experimental fine pitch detector multislice CT scanner with an ultrasmall focal spot x-ray tube and a high-density matrix detector through current CT technology. The latitudinal size of the x-ray tube focal spot was 0.4 mm. The detector dimension was 1824 channels (azimuthal direction) x 32 rows (longitudinal direction) at row width of 0.3125 mm, in which a thinner reflected separator surrounds each detector cell coupled with a large active area photodiode. They were mounted on a commercial 64-slice CT scanner gantry while the scan field of view (50 cm) and gantry rotation speed (0.35 s) can be maintained. The experimental CT scanner demonstrated the spatial resolution of 0.21-0.22 mm (23.8-22.7 lp/cm) with the acrylic slit phantom and in-plane 50%-MTF 9.0 lp/cm and 10%-MTF 22.0 lp/cm. In the longitudinal direction, it demonstrated the spatial resolution of 0.24 mm with the high-resolution insert of the CATPHAN phantom and 0.34 mm as the full width at half maximum of the slice sensitivity profile. In low-contrast detectability, 3 mm at 0.3% was visualized at the CTDI(vol) of 47.2 mGy. Two types of 2.75 mm diameter vessel phantoms with in-stent stenosis at 25%, 50%, and 75% stair steps were scanned, and the reconstructed images can clearly resolve the stenosis at each case. The experimental CT scanner provides high-resolution imaging while maintaining low-contrast detectability, demonstrating the potentiality for clinical applications demanding high spatial resolution, such as imaging of inner ear, lung, and bone, or low-contrast detectability, such as imaging of coronary artery.

  13. Optical coupling study of plastic scintillation detectors: evaluation of different silicon products

    International Nuclear Information System (INIS)

    Hamada, M.M.; Madi Filho, T.; Mesquita, C.H. de

    1990-01-01

    Properties of different optical oils and greases in the range of 320-560 nm were studied. Several parameters as the transmitance, index of refraction, plastic scintillator fluorescence emission and its influence in the resolution and pulse height of the detection system were described. This paper shows a design to analyse the optical quality or adequacy of the silicon oils and greases in the coupling between the detector and the photocathode of the photomultiplier. (author) [pt

  14. Installation and evaluation of a nitrogen-16 detector in the Ford nuclear reactor

    International Nuclear Information System (INIS)

    Burn, R.R.

    1995-01-01

    Core differential temperature is the final measure of steady-state power at the Ford nuclear reactor. During some evolutions, such as changing the number of cooling-tower fans in operation, differential temperature undergoes a transient and does not provide an accurate measure of true power. A 16 N detector was installed to provide a more stable measure of power, even under transient conditions

  15. The crystal zero degree detector at BESIII as a realistic high rate environment for evaluating PANDA data acquisition modules

    International Nuclear Information System (INIS)

    Werner, Marcel

    2015-03-01

    The BESIII experiment located in Beijing, China, is investigating physics in the energy region of the charm-quark via electron positron annihilation reactions. A small detector to be placed in the very forward/backward region around θ=0 at BESIII is foreseen to measure photons from the initial state. This is especially interesting, because it opens the door for various physics measurements over a wide range of energies, even below the experiment's designated energy threshold, which is fixed by the accelerator. This thesis is investigating the capabilities of a crystal zero degree detector (cZDD) consisting of PbWO 4 crystals placed in that region of BESIII. Detailed Geant4-based simulations have been performed, and the energy resolution of the detector has been determined to be σ/μ=0.06+0.025/√(E[GeV]). The determination of the center-of-mass energy √(s) isr after the emission of the photon is of great importance for the study of such events. Preliminary simulations estimated the resolution of the reconstructed √(s) isr using the cZDD information to be significantly better than 10 % for appropriate photon impacts on the detector. Such events can only be investigated, when data from the cZDD and other detectors of BESIII can be correlated. A fast and powerful Data Acquisition (DAQ) capable of performing event correlation in real time is needed. DAQ modules capable of performing real time event correlation are being developed for the PANDA experiment at the future FAIR facility in Darmstadt, Germany. Investigating these modules in a realistic high-rate environment such as provided at BESIII, offers a great opportunity to gain experience in real time event correlation before the start of PANDA. Developments for the cZDD's DAQ using prototype PANDA DAQ modules have been done and successfully tested in experiments with radioactive sources and a beamtest with 210 MeV electrons at the Mainz Microtron.

  16. Evaluation of 16 detector row spiral CT in diagnosing pulmonary embolism

    International Nuclear Information System (INIS)

    Yu Xiaokun; Li Lei

    2008-01-01

    Objective: To investigate the value of 16 detector row spiral CT in the diagnosis of pulmonary embolism(PE). Methods: Imaging data of 20 patients (plain 16 detector row spiral CT scanning plus enhanced scanning imaging) highly suspected of PE was retrospectively analyzed. Results: Among the 20 cases, embolism was showed in 13 patients on 16 detector row spiral CT pulmonary angiography (MSCTPA). 6 cases of the 13 PE's patients have masculine findings on plain MSCT scanning images. Localized tenuous lung markings, dilated pulmonary artery, 'mosaic' sign, pleural or pericardial effusion, local high attenuation centrally in the pulmonary arteries and lung infarction occurred respectively. Conclusion: MSCTPA may be an effective, simple and safe technique for the diagnosis of PE. It was a reliable means in defecting PE However, for the cases unfit for contrast media and cases only suitable for unenhanced CT because of nonspecific heart-pulmonary symptom, noticeable abnormal signs of plain MSCT scanning could suggest the occurrence of pulmonary embolism. (authors)

  17. AN EVALUATION OF THE BASIC CHARACTERISTICS OF A PLASTIC SCINTILLATING FIBRE DETECTOR IN CT RADIATION FIELDS.

    Science.gov (United States)

    Terasaki, Kento; Fujibuchi, Toshioh; Toyoda, Takatoshi; Yoshida, Yutaka; Akasaka, Tsutomu; Nohtomi, Akihiro; Morishita, Junji

    2016-12-01

    The ionisation chamber for computed tomography (CT) is an instrument that is most commonly used to measure the computed tomography dose index. However, it has been reported that the 10 cm effective detection length of the ionisation chamber is insufficient due to the extent of the dose distribution outside the chamber. The purpose of this study was to estimate the basic characteristics of a plastic scintillating fibre (PSF) detector with a long detection length of 50 cm in CT radiation fields. The authors investigated position dependence using diagnostic X-ray equipment and dependencies for energy, dose rate and slice thickness using an X-ray CT system. The PSF detector outputs piled up at a count rate of 10 000 counts ms -1 in dose rate dependence study. With calibration, this detector may be useful as a CT dosemeter with a long detection length except for the measurement at high dose rate. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Physical and subjective evaluation of a three-detector (TRIAD 88) SPECT system

    International Nuclear Information System (INIS)

    D'Souza, M.F.; Mumma, C.G.; Allen, E.W.; Phal, J.J.; Prince, J.R.

    1995-01-01

    The three-detector TRIAD 88 is a variable cylindrical FOV whole-body SPECT system designed for both brain as well as body organ imaging. The system performance was assessed in terms of physical indices and clinical quality. Measures of low contrast resolution using contrast-detail curves, high contrast resolution using LSFs and associated frequency descriptors, display characteristics, system sensitivity, energy resolution and uniformity analysis were utilized. In addition, images of Carlson phantom, Hoffman brain phantom and clinical brain images were used to compare two collimators subjectively. Measurements and calculations were obtained for two sets of parallel hole collimators, i.e., LEUR P AR and LEHR P AR. Of special interest is the consistency among the three detectors. The planar and volume sensitivities for the LEUR P AR collimator were about 58% of those of the LEHR P AR collimator. The planar spatial resolution of the two collimators differed by about 14%. The display was characterized by a logistic model H and D curve. The planar contrast-detail curves demonstrated no statistical difference in lesion detectability between the two collimator types, however SPECT phantom and clinical images demonstrated improved performance with the LEUR P AR collimator. Images of Hoffman single slice brain and Carlson phantoms and Tc-99m (HMPAO) brain images demonstrated excellent image quality. There was similarity in performance parameters of the three detector heads. 49 refs., 6 tabs., 8 figs

  19. Performance Evaluation of Spectroscopic Detectors for LEU Hold-up Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Venkataraman, Ramkumar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Nutter, Greg [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McElroy, Robert Dennis [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-12-06

    The hold-up measurement of low-enriched uranium materials may require use of alternate detector types relative to the measurement of highly enriched uranium. This is in part due to the difference in process scale (i.e., the components are generally larger for low-enriched uranium systems), but also because the characteristic gamma-ray lines from 235U used for assay of highly enriched uranium will be present at a much reduced intensity (on a per gram of uranium basis) at lower enrichments. Researchers at Oak Ridge National Laboratory examined the performance of several standard detector types, e.g., NaI(Tl), LaBr3(Ce), and HPGe, to select a suitable candidate for measuring and quantifying low-enriched uranium hold-up in process pipes and equipment at the Portsmouth gaseous diffusion plant. Detector characteristics, such as energy resolution (full width at half maximum) and net peak count rates at gamma ray energies spanning a range of 60–1332 keV, were measured for the above-mentioned detector types using the same sources and in the same geometry. Uranium enrichment standards (Certified Reference Material no. 969 and Certified Reference Material no. 146) were measured using each of the detector candidates in the same geometry. The net count rates recorded by each detector at 186 keV and 1,001 keV were plotted as a function of enrichment (atom percentage). Background measurements were made in unshielded and shielded configurations under both ambient and elevated conditions of 238U activity. The highly enriched uranium hold-up measurement campaign at the Portsmouth plant was performed on process equipment that had been cleaned out. Therefore, in most cases, the thickness of the uranium deposits was less than the “infinite thickness” for the 186 keV gamma rays to be completely self-attenuated. Because of this, in addition to measuring the 186 keV gamma, the 1,001 keV gamma ray from 234mPa—a daughter of 238U in secular

  20. Modeling and evaluation of a high-resolution CMOS detector for cone-beam CT of the extremities.

    Science.gov (United States)

    Cao, Qian; Sisniega, Alejandro; Brehler, Michael; Stayman, J Webster; Yorkston, John; Siewerdsen, Jeffrey H; Zbijewski, Wojciech

    2018-01-01

    Quantitative assessment of trabecular bone microarchitecture in extremity cone-beam CT (CBCT) would benefit from the high spatial resolution, low electronic noise, and fast scan time provided by complementary metal-oxide semiconductor (CMOS) x-ray detectors. We investigate the performance of CMOS sensors in extremity CBCT, in particular with respect to potential advantages of thin (CMOS x-ray detector incorporating the effects of CsI:Tl scintillator thickness was developed. Simulation studies were performed using nominal extremity CBCT acquisition protocols (90 kVp, 0.126 mAs/projection). A range of scintillator thickness (0.35-0.75 mm), pixel size (0.05-0.4 mm), focal spot size (0.05-0.7 mm), magnification (1.1-2.1), and dose (15-40 mGy) was considered. The detectability index was evaluated for both CMOS and a-Si:H flat-panel detector (FPD) configurations for a range of imaging tasks emphasizing spatial frequencies associated with feature size aobj. Experimental validation was performed on a CBCT test bench in the geometry of a compact orthopedic CBCT system (SAD = 43.1 cm, SDD = 56.0 cm, matching that of the Carestream OnSight 3D system). The test-bench studies involved a 0.3 mm focal spot x-ray source and two CMOS detectors (Dalsa Xineos-3030HR, 0.099 mm pixel pitch) - one with the standard CsI:Tl thickness of 0.7 mm (C700) and one with a custom 0.4 mm thick scintillator (C400). Measurements of modulation transfer function (MTF), detective quantum efficiency (DQE), and CBCT scans of a cadaveric knee (15 mGy) were obtained for each detector. Optimal detectability for high-frequency tasks (feature size of ~0.06 mm, consistent with the size of trabeculae) was ~4× for the C700 CMOS detector compared to the a-Si:H FPD at nominal system geometry of extremity CBCT. This is due to ~5× lower electronic noise of a CMOS sensor, which enables input quantum-limited imaging at smaller pixel size. Optimal pixel size for high-frequency tasks was CMOS

  1. RQ-21A Blackjack Small Tactical Unmanned Aircraft System (STUAS): Initial Operational Test and Evaluation Report

    Science.gov (United States)

    2015-06-29

    Evaluation Report June 2015 This report on the RQ-21A Blackjack Small Tactical Unmanned Aircraft System fulfills the provisions of Title 10...suitability of the RQ-21A Blackjack Small Tactical Unmanned Aircraft System (STUAS) during Initial Operational Test and Evaluation (IOT&E). The Navy’s...66.9 percent). The average service life of the propulsion modules was 48.9 hours, which does not meet the manufacturer’s stated 100-hour

  2. Evaluating scintillators used in radiation detectors of medical imaging systems by the effective fidelity index method

    International Nuclear Information System (INIS)

    Kandarakis, I.; Cavouras, D.; Prassopoulos, P.; Kanellopoulos, E.; Nomicos, C.D.; Panayiotakis, G.S.

    1999-01-01

    Objective: The performance of medical X-ray image receptors depends: (1) on the scintillator light emission efficiency; and (2) on the compatibility of the scintillator light spectrum with the spectral sensitivity of the light detector (film, photocathode, or photodiode), employed in conjunction with the scintillator. In this study, a scintillator performance measure, the effective fidelity index (EFI), is defined as function of both the scintillator light emission efficiency and spectral compatibility. Materials and Method: CsI:Na, Gd 2 O 2 S:Tb and La 2 O 2 S:Tb scintillators were employed in the form of phosphor screens prepared in our laboratory with various coating thicknesses. The screens were irradiated with X-rays employing tube voltages ranging between 50-120 kVp. Results: The EFI performance of CsI:Na was found to increase with screen coating thickness and it was best when combined with the orthochromatic film or the ES/20 photocathode. Gd 2 O 2 S:Tb showed peak EFI performance at 70 mg/cm 2 coating thickness and it was well combined with the light detectors considered. Conclusion: In accordance with our results, CsI:Na may be employed in radiography when adequately protected against humidity. Gd 2 O 2 S:Tb suitability for conventional imaging was verified and it was found that it may be useful in all types of digital imaging. La 2 O 2 S:Tb could also be used in digital detectors of imaging applications demanding medium X-ray tube voltages

  3. Novel Scanning Lens Instrument for Evaluating Fresnel Lens Performance: Equipment Development and Initial Results (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Herrero, R.; Miller, D. C.; Kurtz, S. R.; Anton, I.; Sala, G.

    2013-07-01

    A system dedicated to the optical transmittance characterization of Fresnel lenses has been developed at NREL, in collaboration with the UPM. The system quantifies the optical efficiency of the lens by generating a performance map. The shape of the focused spot may also be analyzed to understand change in the lens performance. The primary instrument components (lasers and CCD detector) have been characterized to confirm their capability for performing optical transmittance measurements. Measurements performed on SoG and PMMA lenses subject to a variety of indoor conditions (e.g., UV and damp heat) identified differences in the optical efficiency of the evaluated lenses, demonstrating the ability of the Scanning Lens Instrument (SLI) to distinguish between the aged lenses.

  4. Ionization detector

    International Nuclear Information System (INIS)

    Steele, D.S.

    1987-01-01

    An ionization detector having an array of detectors has, for example, grounding pads positioned in the spaces between some detectors (data detectors) and other detectors (reference detectors). The grounding pads are kept at zero electric potential, i.e. grounded. The grounding serves to drain away electrons and thereby prevent an unwanted accumulation of charge in the spaces, and cause the electric field lines to be more perpendicular to the detectors in regions near the grounding pads. Alternatively, no empty space is provided there being additional, grounded, detectors provided between the data and reference detectors. (author)

  5. Evaluation of bipolar phototransistors response used as detectors in megavoltage beams generated by a linear accelerator

    International Nuclear Information System (INIS)

    Silva, J.O. da; Magalhaes, C.M.S. de; Santos, L.A.P. dos

    2007-01-01

    Commercial bipolar phototransistors have been used as detectors for low energy X-rays. However, when they are used in high energy X-ray beams, there is a certain loss of sensitivity to the ionizing radiation. This damage is cumulative and irreversible. There are several factors that yield variations in the phototransistor response when it is under high energy radiation, such as its fabrication technology and its electrical characteristics. The aim of this work is to present experimental results that are used to correlate the response curve of SMT (Surface-Mount Technology) bipolar phototransistors with their loss of sensitivity after irradiation from a Linac (linear accelerator) megavoltage beams. (author)

  6. Review of resistance temperature detector time response characteristics. Safety evaluation report

    International Nuclear Information System (INIS)

    1981-08-01

    A Resistance Temperature Detector (RTD) is used extensively for monitoring water temperatures in nuclear reactor plants. The RTD element does not respond instantaneously to changes in water temperature, but rather there is a time delay before the element senses the temperature change, and in nuclear reactors this delay must be factored into the computation of safety setpoints. For this reason it is necessary to have an accurate description of the RTD time response. This report is a review of the current state of the art of describing and measuring this time response

  7. Evaluation of aortogenic embolic stroke using multi-detector row CT (MDCT)

    International Nuclear Information System (INIS)

    Mizuno, Masanori; Ooura, Kazumasa; Yamaguchi, Mao; Katsura, Noriyuki; Terayama, Yasuo

    2010-01-01

    Transesophageal cardioechography is one of the useful tools for detecting aortic arteriosclerosis causing aortogenic cerebral embolism. However, it is difficult to perform this method to all of the patients because of the technical difficulties due to patient's condition, especially the severity of atherosclerosis. To avoid the unexpected and adverse events, we are routinely applying multi-detector row CT (MDCT) to those patients. Among 10 cerebral embolic patients with unidentified embolic origin, MDCT revealed arteriosclerotic changes in aorta inducing mobile thrombus in 3 cases. The above data indicates that MDCT is safe and useful tool for diagnosis of aortogenic embolic stroke. (author)

  8. Evaluations of the commercial spectrometer systems for safeguards applications using the germanium detectors

    International Nuclear Information System (INIS)

    Vo, D.T.

    1998-01-01

    Safeguards applications require the best spectrometer systems with excellent resolution, stability, and throughput. Instruments must perform well in all the situations and environments. Data communication to the computer should be convenient, fast, and reliable. The software should have all the necessary tools and be ease to use. Portable systems should be small in size, lightweight, and have a long battery life. Nine commercially available spectrometer systems are tested with both the planar and coaxial germanium detectors. Considering the performance of the Digital Signal Processors (DSP), digital-based spectroscopy may be the future of gamma-ray spectroscopy

  9. 49 CFR 40.297 - Does anyone have the authority to change a SAP's initial evaluation?

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Does anyone have the authority to change a SAP's... the Return-to-Duty Process § 40.297 Does anyone have the authority to change a SAP's initial... managed-care provider, any service agent) may change in any way the SAP's evaluation or recommendations...

  10. Housing Services for Child Welfare-Involved Families: An Initial Evaluation Using Observational Data

    Science.gov (United States)

    Fowler, Patrick J.; Taylor, Jeremy J.; Rufa, Anne K.

    2011-01-01

    This study evaluated the impact of housing services among child welfare-involved families using observational data. Propensity score matching with data from the National Survey of Child and Adolescent Well-Being compared intact families (n = 183) who received housing services 12 months after initial investigation to nontreated families balanced on…

  11. Using the Concept of "Population Dose" in Planning and Evaluating Community-Level Obesity Prevention Initiatives

    Science.gov (United States)

    Cheadle, Allen; Schwartz, Pamela M.; Rauzon, Suzanne; Bourcier, Emily; Senter, Sandra; Spring, Rebecca; Beery, William L.

    2013-01-01

    When planning and evaluating community-level initiatives focused on policy and environment change, it is useful to have estimates of the impact on behavioral outcomes of particular strategies (e.g., building a new walking trail to promote physical activity). We have created a measure of estimated strategy-level impact--"population dose"--based on…

  12. Social capital, agricultural innovation and the evaluation of agricultural development initiatives

    NARCIS (Netherlands)

    Rijn, van F.C.

    2014-01-01

    In this thesis, I show that social capital has an important role in the evaluation of development initiatives targeting agricultural innovation. Social capital and agricultural innovation are naturally linked from an innovation system perspective in which innovations result from the integration

  13. Evaluation of a SiPM array detector coupled to a LFS-3 pixellated scintillator for PET/MR applications

    International Nuclear Information System (INIS)

    David, Stratos; Fysikopoulos, Eleftherios; Georgiou, Maria; Loudos, George

    2015-01-01

    SiPM arrays are insensitive to magnetic fields and thus good candidates for hybrid PET/MR imaging systems. Moreover, due to their small size and flexibility can be used in dedicated small field of view small animal imaging detectors and especially in head PET/MR studies in mice. Co-doped LFS-3 scintillator crystals have higher light yield and slightly faster response than that of LSO:Ce mainly due to the co-doped activation of emission centers with varying materials such as Ce, Gd, Sc, Y, La, Tb, or Ca distributed at the molecular scale through the lutetium silicate crystal host. The purpose of this study is to investigate the behavior of the SensL ArraySL-4 (4x4 element array of 3x3 mm 2 silicon photomultipliers) optical detector coupled to a 6x6 LFS-3 scintillator array, with 2x2x5 mm 3 crystal size elements, for possible applications in small field of view PET/MR imaging detectors. We have designed a symmetric resistive charge division circuit to read out the signal outputs of 4x4 pixel SiPM array reducing the 16 pixel outputs of the photodetector to 4 position signals. The 4 position signals were digitized using free running Analog to Digital Converters. The ADCs sampling rate was 50 MHz. An FPGA (Spartan 6 LX150T) was used for triggering and digital signal processing of the pulses. Experimental evaluation was carried out with 22 Na radioactive source and the parameters studied where energy resolution and peak to valley ratio. The first preliminary results of the evaluation shows a clear visualization of the discrete 2x2x5 mm 3 LFS-3 scintillator elements. The mean peak to valley ratio of the horizontal profiles on the raw image was measured equal to 11 while the energy resolution was calculated equal to 30% at the central pixels.

  14. Evaluation of a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography of scaphoid fixation screws.

    Science.gov (United States)

    Filli, Lukas; Marcon, Magda; Scholz, Bernhard; Calcagni, Maurizio; Finkenstädt, Tim; Andreisek, Gustav; Guggenberger, Roman

    2014-12-01

    The aim of this study was to evaluate a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography (FDCT) of scaphoid fixation screws. FDCT has gained interest in imaging small anatomic structures of the appendicular skeleton. Angiographic C-arm systems with flat detectors allow fluoroscopy and FDCT imaging in a one-stop procedure emphasizing their role as an ideal intraoperative imaging tool. However, FDCT imaging can be significantly impaired by artefacts induced by fixation screws. Following ethical board approval, commercially available scaphoid fixation screws were inserted into six cadaveric specimens in order to fix artificially induced scaphoid fractures. FDCT images corrected with the algorithm were compared to uncorrected images both quantitatively and qualitatively by two independent radiologists in terms of artefacts, screw contour, fracture line visibility, bone visibility, and soft tissue definition. Normal distribution of variables was evaluated using the Kolmogorov-Smirnov test. In case of normal distribution, quantitative variables were compared using paired Student's t tests. The Wilcoxon signed-rank test was used for quantitative variables without normal distribution and all qualitative variables. A p value of < 0.05 was considered to indicate statistically significant differences. Metal artefacts were significantly reduced by the correction algorithm (p < 0.001), and the fracture line was more clearly defined (p < 0.01). The inter-observer reliability was "almost perfect" (intra-class correlation coefficient 0.85, p < 0.001). The prototype correction algorithm in FDCT for metal artefacts induced by scaphoid fixation screws may facilitate intra- and postoperative follow-up imaging. Flat detector computed tomography (FDCT) is a helpful imaging tool for scaphoid fixation. The correction algorithm significantly reduces artefacts in FDCT induced by scaphoid fixation screws. This may facilitate intra

  15. Monte Carlo evaluation of the neutron detection efficiency of a superheated drop detector

    Energy Technology Data Exchange (ETDEWEB)

    Gualdrini, G F [ENEA, Centro Ricerche ` Ezio Clementel` , Bologna (Italy). Dipt. Ambiente; D` Errico, F; Noccioni, P [Pisa, Univ. (Italy). Dipt. di Costruzioni Meccaniche e Nucleari

    1997-03-01

    Neuron dosimetry has recently gained renewed attention, following concerns on the exposure of crew members on board aircraft, and of workers around the increasing number of high energy accelerators for medical and research purpose. At the same time the new operational qualities for radiation dosimetry introduced by ICRU and the ICRP, aiming at a unified metrological system applicable to all types of radiation exposure, involved the need to update current devices in order to meet new requirements. Superheated Drop (Bubble) Detectors (SDD) offer an alternative approach to neutron radiation protection dosimetry. The SDDs are currently studied within a large collaborative effort involving Yale University. New Haven CT, Pisa (IT) University, the Physikalisch-Technische Bundesanstalt, Braunschweig D, and ENEA (Italian National Agency for new Technologies Energy and the Environment) Centre of Bologna. The detectors were characterised through calibrations with monoenergetic neutron beams and where experimental investigations were inadequate or impossible, such as in the intermediate energy range , parametric Monte Carlo calculations of the response were carried out. This report describes the general characteristic of the SDDs along with the Monte Carlo computations of the energy response and a comparison with the experimental results.

  16. Neutron Fluence Evaluation using an Am-Be Neutron Sources Assembly and P ADC Detectors

    International Nuclear Information System (INIS)

    Seddik, U.

    2008-01-01

    An assembly of four 241 Am-Be sources has been constructed at Nuclear Reactions Unit (NRU) of Nuclear Research Center (NRU) to perform analysis of different materials using thermal and fast neutrons. In the present paper, we measure the value of transmittance (T) in percentage of etched CR-39 detectors using a spectrophotometer at different neutron fluences ,to relate the transmittance of the detector with the neutron fluence values. The exposed samples to neutrons with accumulated fluence of order between 10 10 and 10 12 cm -2 were etched for 15 time intervals between 10-600 min in 6.25 N NaOH at 70 degree C. The etched samples were analyzed using Tech 8500 II spectrophotometer. A trend of the sample transmission and the etching time is observed which is different for each fluence value. A linear relation between the transmittance decay constant and the neutron fluence is observed which could be used as a calibration to determine unknown neutron fluence

  17. Development of a model-independent evaluation of photon-deuteron reactions for the SAPHIR detector

    International Nuclear Information System (INIS)

    Wolf, A.

    1993-01-01

    The SAPHIR detector measures photon induced reactions with many particles in the final state. Thus a detailed investigation of those processes at photon energies between 0.4 and 3.3 GeV is possible. The interpretation of the distribution of the sample of events, which SAPHIR is able to reconstruct, has to be done after a correction of influences induced by the detector acceptance. In this work a model independent method of correcting and analysing the data is discussed. The implementation of the basic tools of this analysis is described and first tests with simulated and real events are performed. SAPHIR uses a time-of-flight system for the identification of particles. This work describes the structure of a program library, which supports an easy way of decoding the digitizations of this system (including calibration of the hardware) and obtaining the flight time for a particle in a event. The necessary step for calibrating the system are outlined, too. (orig.)

  18. Evaluation of the Neutron Detector Response for Cosmic Ray Energy Spectrum by Monte Carlo Transport Simulation

    International Nuclear Information System (INIS)

    Pazianotto, Mauricio T.; Carlson, Brett V.; Federico, Claudio A.; Gonzalez, Odair L.

    2011-01-01

    Neutrons generated by the interaction of cosmic rays with the atmosphere make an important contribution to the dose accumulated in electronic circuits and aircraft crew members at flight altitude. High-energy neutrons are produced in spallation reactions and intranuclear cascade processes by primary cosmic-ray particle interactions with atoms in the atmosphere. These neutrons can produce secondary neutrons and also undergo a moderation process due to atmosphere interactions, resulting in a wider energy spectrum, ranging from thermal energies (0.025 eV) to energies of several hundreds of MeV. The Long-Counter (LC) detector is a widely used neutron detector designed to measure the directional flux of neutrons with about constant response over a wide energy range (thermal to 20 MeV). ). Its calibration process and the determination of its energy response for the wide-energy of cosmic ray induced neutron spectrum is a very difficult process due to the lack of installations with these capabilities. The goal of this study is to assess the behavior of the response of a Long Counter using the Monte Carlo (MC) computational code MCNPX (Monte Carlo N-Particle eXtended). The dependence of the Long Counter response on the angle of incidence, as well as on the neutron energy, will be carefully investigated, compared with the experimental data previously obtained with 241 Am-Be and 252 Cf neutron sources and extended to the neutron spectrum produced by cosmic rays. (Author)

  19. Evaluating financial education initiatives in South Africa: The importance of multiple evaluation approaches

    Directory of Open Access Journals (Sweden)

    Emily Massey

    2016-06-01

    Objectives: This study aims to show that, particularly in a South African context, where investment in financial education interventions is mandated by the Financial Sector Codes, impact should not be the only criterion assessed when evaluating financial education projects. Research method and design: This study was informed by a literature review, a synthesis of team experience on a range of financial education projects in South Africa and the development of case studies. Results: Describing the success or failure of a project needs to go beyond impact and explore factors such as project relevance, design and quality. In order to verify these other factors, different types of evaluations are necessary at the various stages of the project’s life-cycle. Conclusion: Expanding the learning objective beyond the exclusive identification of whether financial behaviour was achieved is particularly important where financial education projects, and the monitoring and evaluation thereof, is mandated. In the African context, where resources are scarce, money for monitoring and evaluation should be selectively channelled into determining project relevance, effectiveness, efficiency and then only impact.

  20. Time-lapse cased hole reservoir evaluation based on the dual-detector neutron lifetime log: the CHES II approach

    International Nuclear Information System (INIS)

    DeVries, M.R.; Fertl, W.

    1977-01-01

    A newly developed cased hole analysis technique provides detailed information on (1) reservoir rock properties, such as porosity, shaliness, and formation permeability, (2) reservoir fluid saturation, (3) distinction of oil and gas pays, (4) state of reservoir depletion, such as cumulative hydrocarbon-feet at present time and cumulative hydrocarbon-feet already depleted (e.g., the sum of both values then giving the cumulative hydrocarbon-feet originally present), and (5) monitoring of hydrocarbon/water and gas/oil contacts behind pipe. The basic well log data required for this type of analysis include the Dual-Detector Neutron Lifetime Log, run in casing at any particular time in the life of a reservoir, and the initial open-hole resistivity log. In addition, porosity information from open-hole porosity log(s) or core data is necessary. Field examples from several areas are presented and discussed in the light of formation reservoir and hydrocarbon production characteristics

  1. Measurement of {sigma}(e{sup +}e{sup -}{yields}{pi}{sup +}{pi}{sup -}) from threshold to 0.85 GeV{sup 2} using initial state radiation with the KLOE detector

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosino, F. [Dipartimento di Scienze Fisiche dell' Universita ' Federico II' , Napoli (Italy); INFN Sezione di Napoli, Napoli (Italy); Archilli, F. [Dipartimento di Fisica dell' Universita ' Tor Vergata, Roma (Italy); INFN Sezione di Roma Tor Vergata, Roma (Italy); Beltrame, P., E-mail: beltrame@kph.uni-mainz.de [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany); Bencivenni, G. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Bini, C. [Dipartimento di Fisica dell' Universita ' La Sapienza' , Roma (Italy); INFN Sezione di Roma, Roma (Italy); Bloise, C. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Bocchetta, S. [Dipartimento di Fisica dell' Universita ' Roma Tre' , Roma (Italy); INFN Sezione di Roma Tre, Roma (Italy); Bossi, F. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Branchini, P. [INFN Sezione di Roma Tre, Roma (Italy); Capon, G.; Capussela, T. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Ceradini, F. [Dipartimento di Fisica dell' Universita ' Roma Tre' , Roma (Italy); INFN Sezione di Roma Tre, Roma (Italy); Ciambrone, P.; De Lucia, E. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); De Santis, A. [Dipartimento di Fisica dell' Universita ' La Sapienza' , Roma (Italy); INFN Sezione di Roma, Roma (Italy); De Simone, P. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); De Zorzi, G. [Dipartimento di Fisica dell' Universita ' La Sapienza' , Roma (Italy); INFN Sezione di Roma, Roma (Italy); Denig, A., E-mail: denig@kph.uni-mainz.de [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany); Di Domenico, A. [Dipartimento di Fisica dell' Universita ' La Sapienza' , Roma (Italy); INFN Sezione di Roma, Roma (Italy); Di Donato, C. [INFN Sezione di Napoli, Napoli (Italy)

    2011-06-06

    We have measured the cross section of the radiative process e{sup +}e{sup -}{yields}{pi}{sup +}{pi}{sup -}{gamma} with the KLOE detector at the Frascati {phi}-factory DA{Phi}NE, from events taken at a CM energy W=1 GeV. Initial state radiation allows us to obtain the cross section for e{sup +}e{sup -}{yields}{pi}{sup +}{pi}{sup -}, the pion form factor {sup 2}|F{sub {pi}}| and the dipion contribution to the muon magnetic moment anomaly, {Delta}a{sub {mu}}{sup {pi}{pi}}=(478.5{+-}2.0{sub stat}{+-}5.0{sub syst}{+-}4.5{sub th})x10{sup -10} in the range 0.1evaluation of a{sub {mu}} and the value measured by the Muon g-2 collaboration at BNL is confirmed.

  2. Silicon detectors

    International Nuclear Information System (INIS)

    Klanner, R.

    1984-08-01

    The status and recent progress of silicon detectors for high energy physics is reviewed. Emphasis is put on detectors with high spatial resolution and the use of silicon detectors in calorimeters. (orig.)

  3. The Evaluation of the Initial Shear Modulus of Selected Cohesive Soils

    Science.gov (United States)

    Gabryś, Katarzyna; Szymański, Alojzy

    2015-06-01

    The paper concerns the evaluation of the initial stiffness of selected cohesive soils based on laboratory tests. The research materials used in this study were clayey soils taken from the area of the road embankment No. WD-18, on the 464th km of the S2 express-way, Konotopa-Airport route, Warsaw. The initial stiffness is represented here by the shear modulus (Gmax) determined during resonant column tests. In the article, a number of literature empirical formulas for defining initial value of the shear modulus of soils being examined were adopted from the literature in order to analyze the data set. However, a large discrepancy between laboratory test results and the values of Gmax calculated from empirical relationships resulted in the rejection of these proposals. They are inaccurate and do not allow for an exact evaluation of soil stiffness for selected cohesive soils. Hence, the authors proposed their own empirical formula that enables the evaluation of the test soils' Gmax in an easy and uncomplicated way. This unique formula describes mathematically the effect of certain soil parameters, namely mean effective stress ( p') and void ratio (e), on the initial soil stiffness.

  4. Using the Hospital Nutrition Environment Scan to Evaluate Health Initiative in Hospital Cafeterias.

    Science.gov (United States)

    Derrick, Jennifer Willahan; Bellini, Sarah Gunnell; Spelman, Julie

    2015-11-01

    Health-promoting environments advance health and prevent chronic disease. Hospitals have been charged to promote health and wellness to patients, communities, and 5.3 million adults employed in United States health care environments. In this cross-sectional observational study, the Hospital Nutrition Environment Scan (HNES) was used to measure the nutrition environment of hospital cafeterias and evaluate the influence of the LiVe Well Plate health initiative. Twenty-one hospitals in the Intermountain West region were surveyed between October 2013 and May 2014. Six hospitals participated in the LiVe Well Plate health initiative and were compared with 15 hospitals not participating. The LiVe Well Plate health initiative identified and promoted a healthy meal defined as health initiative branding were also posted at point of purchase. Hospital cafeterias were scored on four subcategories: facilitators and barriers, grab-and-go items, menu offerings, and selection options at point of purchase. Overall, hospitals scored 35.3±13.7 (range=7 to 63) points of 86 total possible points. Cafeterias in health initiative hospitals had significantly higher mean nutrition composite scores compared with non-health initiative hospitals (49.2 vs 29.7; Penvironment of hospital cafeterias. Additional research is needed to quantify and strategize ways to improve nutrition environments within hospital cafeterias and assess the influence on healthy lifestyle behaviors. Copyright © 2015 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

  5. Evaluation of strength and failure of brittle rock containing initial cracks under lithospheric conditions

    Science.gov (United States)

    Li, Xiaozhao; Qi, Chengzhi; Shao, Zhushan; Ma, Chao

    2018-02-01

    Natural brittle rock contains numerous randomly distributed microcracks. Crack initiation, growth, and coalescence play a predominant role in evaluation for the strength and failure of brittle rocks. A new analytical method is proposed to predict the strength and failure of brittle rocks containing initial microcracks. The formulation of this method is based on an improved wing crack model and a suggested micro-macro relation. In this improved wing crack model, the parameter of crack angle is especially introduced as a variable, and the analytical stress-crack relation considering crack angle effect is obtained. Coupling the proposed stress-crack relation and the suggested micro-macro relation describing the relation between crack growth and axial strain, the stress-strain constitutive relation is obtained to predict the rock strength and failure. Considering different initial microcrack sizes, friction coefficients and confining pressures, effects of crack angle on tensile wedge force acting on initial crack interface are studied, and effects of crack angle on stress-strain constitutive relation of rocks are also analyzed. The strength and crack initiation stress under different crack angles are discussed, and the value of most disadvantaged angle triggering crack initiation and rock failure is founded. The analytical results are similar to the published study results. Rationality of this proposed analytical method is verified.

  6. Variations in thematic mapper spectra of soil related to tillage and crop residue management - Initial evaluation

    Science.gov (United States)

    Seeley, M. W.; Ruschy, D. L.; Linden, D. R.

    1983-01-01

    A cooperative research project was initiated in 1982 to study differences in thematic mapper spectral characteristics caused by variable tillage and crop residue practices. Initial evaluations of radiometric data suggest that spectral separability of variably tilled soils can be confounded by moisture and weathering effects. Separability of bare tilled soils from those with significant amounts of corn residue is enhanced by wet conditions, but still possible under dry conditions when recent tillage operations have occurred. In addition, thematic mapper data may provide an alternative method to study the radiant energy balance at the soil surface in conjunction with variable tillage systems.

  7. Preliminary evaluation of a method using an FID (flame ionization detector) for measurement of methanol in auto emissions. Final report

    International Nuclear Information System (INIS)

    Gabele, P.A.; Ray, W.D.; Duncan, J.; Burton, C.

    1987-09-01

    This report evaluates a simplified technique for estimating methanol emission rates in auto exhaust. The technique, referred to as the FID Bubbled Method or FBM, is based in principle on the fact that, while hydrocarbons are not readily absorbed in water, methanol is. Hence, by using a heated flame ionization detector to measure the organic mass in samples before and after bubbling them in water, the quantity of methanol originally present can be estimated by taking the difference between the measurements. Evaluation of the method was done by comparing methanol measurements using the FBM with measurements made using an established reference method. Results showed poor to fair agreement between the two methods. The FBM appeared better at estimating methanol emission rates from evaporative tests than from exhaust tests and also exhibited better accuracy for samples containing higher levels of methanol

  8. Evaluation of indigenously developed plastic scintillator sheet detector for surface radioactive contamination monitoring application

    International Nuclear Information System (INIS)

    Sahani, R.M.; Chaudhary, H.S.; Mahala, V.K.; Senwar, K.R.; Meena, J.P.

    2018-01-01

    Radioactive contamination may be caused by release of radioactivity in the environment due to accident at nuclear plant/reactor or spillage of loose radioactive materials in a laboratory. The protection of workers from potentially hazardous radiations emitted by the contaminants is a matter of prime concern. The detection of such radiations requires a monitoring system capable of measuring the level of radioactivity at the contaminated site. Plastic scintillators are widely used for large area radiation monitoring due to the ease of preparation in different shape and sizes. These detectors are sensitive to beta and gamma radiation therefore can be used for monitoring of beta and gamma contamination. In this paper, performance results of indigenously developed plastic scintillator sheet of area 800 cm 2 are reported

  9. Evaluation of a photon counting Medipix3RX CZT spectral x-ray detector

    Science.gov (United States)

    Jorgensen, Steven M.; Vercnocke, Andrew J.; Rundle, David S.; Butler, Philip H.; McCollough, Cynthia H.; Ritman, Erik L.

    2016-10-01

    We assessed the performance of a cadmium zinc telluride (CZT)-based Medipix3RX x-ray detector as a candidate for micro-computed tomography (micro-CT) imaging. This technology was developed at CERN for the Large Hadron Collider. It features an array of 128 by 128, 110 micrometer square pixels, each with eight simultaneous threshold counters, five of which utilize real-time charge summing, significantly reducing the charge sharing between contiguous pixels. Pixel response curves were created by imaging a range of x-ray intensities by varying x-ray tube current and by varying the exposure time with fixed x-ray current. Photon energy-related assessments were made by flooding the detector with the tin foil filtered emission of an I-125 radioisotope brachytherapy seed and sweeping the energy threshold of each of the four charge-summed counters of each pixel in 1 keV steps. Long term stability assessments were made by repeating exposures over the course of one hour. The high properly-functioning pixel yield (99%), long term stability (linear regression of whole-chip response over one hour of acquisitions: y = -0.0038x + 2284; standard deviation: 3.7 counts) and energy resolution (2.5 keV FWHM (single pixel), 3.7 keV FWHM across the full image) make this device suitable for spectral micro-CT. The charge summing performance effectively reduced the measurement corruption caused by charge sharing which, when unaccounted for, shifts the photon energy assignment to lower energies, degrading both count and energy accuracy. Effective charge summing greatly improves the potential for calibrated, energy-specific material decomposition and K edge difference imaging approaches.

  10. Evaluating nuclear power: voter choice on the California nuclear energy initiative. Executive summary

    International Nuclear Information System (INIS)

    Hensler, D.R.; Hensler, C.P.

    1979-07-01

    In 1976, under grants from the National Science Foundation and the Ford Foundation, The Rand Corporation conducted a set of surveys of Californians' attitudes toward nuclear power nd Proposition 15 that we hoped would illuminate the reasons for the voters' decision on the nuclear initiative. The study focused on the attitudes of the general public; it did not investigate the factors that motivate activists on both sides of the nuclear controversy. The study was limited to California, but because results indicate that attitudes of Californians are similar to attitudes reported in nationwide surveys, we believe that our findings have broader applicability. The objectives of the study were to: describe public knowledge, beliefs, and evaluation of nuclear energy development; analyze the relationship between beliefs and evaluation of nuclear energy; investigate the relationship between critical beliefs about nuclear energy and general political orientations, trust in government and other political and social institutions, and social background characteristics; describe public knowledge, beliefs, and evaluation of Proposition 15, the California nuclear energy initiative; and investigate the relationship between individuals' voting decisions on Proposition 15 and their evaluations of nuclear power and responses to the initiative campaign

  11. Painless thyroiditis associated to thyroid carcinoma: role of initial ultrasonography evaluation.

    Science.gov (United States)

    Valentini, Raisa Bressan; Macedo, Bruno Mussoi de; Izquierdo, Rogério Friedrich; Meyer, Erika Laurini Souza

    2016-04-01

    Even though it is a rare event, most associations of thyroid carcinoma with subacute thyroiditis described in the literature are related to its granulomatous form (Quervain's thyroiditis). We present a patient with subacute lymphocytic thyroiditis (painless thyroiditis) and papillary thyroid cancer that was first suspected in an initial ultrasound evaluation. A 30-year old female patient who was referred to the emergency room due to hyperthyroidism symptoms was diagnosed with painless thyroiditis established by physical examination and laboratory findings. With the presence of a palpable painless thyroid nodule an ultrasound was prescribed and the images revealed a suspicious thyroid nodule, microcalcification focus in the heterogeneous thyroid parenquima and cervical lymphadenopathy. Fine needle aspiration biopsy was taken from this nodule; cytology was assessed for compatibility with papillary thyroid carcinoma. Postsurgical pathology evaluation showed a multicentric papillary carcinoma and lymphocytic infiltration. Subacute thyroiditis, regardless of type, may produce transitory ultrasound changes that obscure the coexistence of papillary carcinoma. Due to this, initial thyroid ultrasound evaluation should be delayed until clinical recovery. We recommended a thyroid ultrasound exam for initial evaluation of painless thyroiditis, particularly in patients with palpable thyroid nodule. Further cytological examination is recommended in cases presenting with suspect thyroid nodule and/or non-nodular hypoechoic (> 1 cm) or heterogeneous areas with microcalcification focus.

  12. Evaluation of initial degradation in stress corrosion cracking by magnetic methods

    International Nuclear Information System (INIS)

    Takaya, Shigeru; Suzuki, Takayuki; Matsumoto, Yoshihiro; Demachi, Kazuyuki; Uesaka, Mitsuru

    2003-01-01

    Two magnetic methods are proposed for the evaluation of initial degradations of type 304 stainless steel in stress corrosion cracking (SCC). The first one is the measurement of the distribution of chromium depletion by means of a magnetic force microscope (MFM). MFM observations are performed for some samples sensitized in various conditions, and the obtained results coincide with the expected ones from the chromium behavior. Moreover, the phase distributions in the solution-annealed and sensitized states are observed by electron backscatter pattern technique. The observation results show that the phase transformation from the austenite phase to the martensite phase occurred along grain boundaries where the chromium was depleted. The second one is the detection of initial SCC cracks by measurement of magnetic flux densities. In-situ measurement of magnetic flux density during the SCC test and MFM observation reveal the relation of initial SCC cracks and magnetic properties. (author)

  13. Defects level evaluation of LiTiZn ferrite ceramics using temperature dependence of initial permeability

    Science.gov (United States)

    Malyshev, A. V.; Petrova, A. B.; Sokolovskiy, A. N.; Surzhikov, A. P.

    2018-06-01

    The method for evaluating the integral defects level and chemical homogeneity of ferrite ceramics based on temperature dependence analysis of initial permeability is suggested. A phenomenological expression for the description of such dependence was suggested and an interpretation of its main parameters was given. It was shown, that the main criterion of the integral defects level of ferrite ceramics is relation of two parameters correlating with elastic stress value in a material. An indicator of structural perfection can be a maximum value of initial permeability close to Curie point as well. The temperature dependences of initial permeability have analyzed for samples sintered in laboratory conditions and for the ferrite industrial product. The proposed method allows controlling integral defects level of the soft ferrite products and has high sensitivity compare to typical X-ray methods.

  14. Evaluation of the "Foundations in Knowledge Translation" training initiative: preparing end users to practice KT.

    Science.gov (United States)

    Park, Jamie S; Moore, Julia E; Sayal, Radha; Holmes, Bev J; Scarrow, Gayle; Graham, Ian D; Jeffs, Lianne; Timmings, Caitlyn; Rashid, Shusmita; Johnson, Alekhya Mascarenhas; Straus, Sharon E

    2018-04-25

    Current knowledge translation (KT) training initiatives are primarily focused on preparing researchers to conduct KT research rather than on teaching KT practice to end users. Furthermore, training initiatives that focus on KT practice have not been rigorously evaluated and have focused on assessing short-term outcomes and participant satisfaction only. Thus, there is a need for longitudinal training evaluations that assess the sustainability of training outcomes and contextual factors that may influence outcomes. We evaluated the KT training initiative "Foundations in KT" using a mixed-methods longitudinal design. "Foundations in KT" provided training in KT practice and included three tailored in-person workshops, coaching, and an online platform for training materials and knowledge exchange. Two cohorts were included in the study (62 participants, including 46 "Foundations in KT" participants from 16 project teams and 16 decision-maker partners). Participants completed self-report questionnaires, focus groups, and interviews at baseline and at 6, 12, 18, and 24 months after the first workshop. Participant-level outcomes include survey results which indicated that participants' self-efficacy in evidence-based practice (F(1,8.9) = 23.7, p = 0.001, n = 45), KT activities (F(1,23.9) = 43.2, p training initiative helped participants achieve their KT project objectives, plan their projects, and solve problems over time. Contextual factors include teams with high self-reported organizational capacity and commitment to implement at the start of their project had buy-in from upper management that resulted in secured funding and resources for their project. Training initiative outcomes include participants who applied the KT knowledge and skills they learned to other projects by sharing their knowledge informally with coworkers. Sustained spread of KT practice was observed with five teams at 24 months. We completed a longitudinal evaluation of a KT

  15. Modelling of illuminated current–voltage characteristics to evaluate leakage currents in long wavelength infrared mercury cadmium telluride photovoltaic detectors

    International Nuclear Information System (INIS)

    Gopal, Vishnu; Qiu, WeiCheng; Hu, Weida

    2014-01-01

    The current–voltage characteristics of long wavelength mercury cadmium telluride infrared detectors have been studied using a recently suggested method for modelling of illuminated photovoltaic detectors. Diodes fabricated on in-house grown arsenic and vacancy doped epitaxial layers were evaluated for their leakage currents. The thermal diffusion, generation–recombination (g-r), and ohmic currents were found as principal components of diode current besides a component of photocurrent due to illumination. In addition, both types of diodes exhibited an excess current component whose growth with the applied bias voltage did not match the expected growth of trap-assisted-tunnelling current. Instead, it was found to be the best described by an exponential function of the type, I excess  = I r0  + K 1 exp (K 2 V), where I r0 , K 1 , and K 2 are fitting parameters and V is the applied bias voltage. A study of the temperature dependence of the diode current components and the excess current provided the useful clues about the source of origin of excess current. It was found that the excess current in diodes fabricated on arsenic doped epitaxial layers has its origin in the source of ohmic shunt currents. Whereas, the source of excess current in diodes fabricated on vacancy doped epitaxial layers appeared to be the avalanche multiplication of photocurrent. The difference in the behaviour of two types of diodes has been attributed to the difference in the quality of epitaxial layers

  16. Evaluation of Origin Ensemble algorithm for image reconstruction for pixelated solid-state detectors with large number of channels

    Science.gov (United States)

    Kolstein, M.; De Lorenzo, G.; Mikhaylova, E.; Chmeissani, M.; Ariño, G.; Calderón, Y.; Ozsahin, I.; Uzun, D.

    2013-04-01

    The Voxel Imaging PET (VIP) Pathfinder project intends to show the advantages of using pixelated solid-state technology for nuclear medicine applications. It proposes designs for Positron Emission Tomography (PET), Positron Emission Mammography (PEM) and Compton gamma camera detectors with a large number of signal channels (of the order of 106). For PET scanners, conventional algorithms like Filtered Back-Projection (FBP) and Ordered Subset Expectation Maximization (OSEM) are straightforward to use and give good results. However, FBP presents difficulties for detectors with limited angular coverage like PEM and Compton gamma cameras, whereas OSEM has an impractically large time and memory consumption for a Compton gamma camera with a large number of channels. In this article, the Origin Ensemble (OE) algorithm is evaluated as an alternative algorithm for image reconstruction. Monte Carlo simulations of the PET design are used to compare the performance of OE, FBP and OSEM in terms of the bias, variance and average mean squared error (MSE) image quality metrics. For the PEM and Compton camera designs, results obtained with OE are presented.

  17. Evaluation of the Electronic Bubbler Gas Monitoring System for High Flow in the BaBar Detector

    International Nuclear Information System (INIS)

    Little, Angela

    2003-01-01

    We evaluated the gas monitoring system in the Instrumented Flux Return (IFR) portion of the BaBar detector at the Stanford Linear Accelerator Center (SLAC) to determine its suitability for flows greater than 80 cc/min. Future modifications to the IFR involve particle detectors with a higher gas flow rate than currently in use. Therefore, the bubbler system was tested to determine if it can handle high flow rates. Flow rates between 80 and 240 cc/min were analyzed through short term calibration and long term stability tests. The bubbler system was found to be reliable for flow rates between 80 and 160 cc/min. For flow rates between 200 and 240 cc/min, electronic instabilities known as baseline spikes caused a 10-20% error in the bubble rate. An upgrade would be recommended for use of the bubbler system at these flow rates. Since the planned changes in the IFR will require a maximum flow of 150 cc/min, the bubbler system can sufficiently handle the new gas flow rates

  18. Assessing Patients’ Cognitive Therapy Skills: Initial Evaluation of the Competencies of Cognitive Therapy Scale

    Science.gov (United States)

    Strunk, Daniel R.; Hollars, Shannon N.; Adler, Abby D.; Goldstein, Lizabeth A.; Braun, Justin D.

    2014-01-01

    In Cognitive Therapy (CT), therapists work to help patients develop skills to cope with negative affect. Most current methods of assessing patients’ skills are cumbersome and impractical for clinical use. To address this issue, we developed and conducted an initial psychometric evaluation of self and therapist reported versions of a new measure of CT skills: the Competencies of Cognitive Therapy Scale (CCTS). We evaluated the CCTS at intake and post-treatment in a sample of 67 patients participating in CT. The CCTS correlated with a preexisting measure of CT skills (the Ways of Responding Questionnaire) and was also related to concurrent depressive symptoms. Across CT, self-reported improvements in CT competencies were associated with greater changes in depressive symptoms. These findings offer initial evidence for the validity of the CCTS. We discuss the CCTS in comparison with other measures of CT skills and suggest future research directions. PMID:25408560

  19. Spatial resolution evaluation with a pair of two four-layer DOI detectors for small animal PET scanner: jPET-RD

    International Nuclear Information System (INIS)

    Nishikido, Fumihiko; Tsuda, Tomoaki; Yoshida, Eiji; Inadama, Naoko; Shibuya, Kengo; Yamaya, Taiga; Kitamura, Keishi; Takahashi, Kei; Ohmura, Atsushi; Murayama, Hideo

    2008-01-01

    We are developing a small animal PET scanner, 'jPET-RD' to achieve high sensitivity as well as high spatial resolution by using four-layer depth-of-interaction (DOI) detectors. The jPET-RD is designed with two detector rings. Each detector ring is composed of six DOI detectors arranged hexagonally. The diameter of the field-of-view (FOV) is 8.8 cm, which is smaller than typical small animal PET scanners on the market now. Each detector module consists of a crystal block and a 256-channel flat panel position-sensitive photomultiplier tube. The crystal block, consisting of 32x32x4 crystal (4096 crystals, each 1.46 mmx1.46 mmx4.5 mm) and a reflector, is mounted on the 256ch FP-PMT. In this study, we evaluated the spatial resolution of reconstructed images with the evaluation system of two four-layer DOI detectors which consist of 32x32x4 LYSO (Lu: 98%, Y: 2%) crystals coupled on the 256ch FP-PMT by using RTV rubber. The spatial resolution of 1.5 mm was obtained at the center of the FOV by the filtered back projection. The spatial resolution, better than 2 mm in the whole FOV, was also achieved with DOI while the spatial resolution without DOI was degraded to 3.3 mm

  20. Spatial resolution evaluation with a pair of two four-layer DOI detectors for small animal PET scanner: jPET-RD

    Energy Technology Data Exchange (ETDEWEB)

    Nishikido, Fumihiko [National Institute of Radiological Sciences, Anagawa 4-9-1 Inage-ku, Chiba-shi, Chiba 263-8555 (Japan)], E-mail: funis@nirs.go.jp; Tsuda, Tomoaki [Shimadzu Corporation, Nishinokyo Kuwabaracho 1 Nakagyo-ku, Kyoto-shi, Kyoto 604-8511 (Japan); Yoshida, Eiji; Inadama, Naoko; Shibuya, Kengo; Yamaya, Taiga [National Institute of Radiological Sciences, Anagawa 4-9-1 Inage-ku, Chiba-shi, Chiba 263-8555 (Japan); Kitamura, Keishi [Shimadzu Corporation, Nishinokyo Kuwabaracho 1 Nakagyo-ku, Kyoto-shi, Kyoto 604-8511 (Japan); Takahashi, Kei [National Institute of Radiological Sciences, Anagawa 4-9-1 Inage-ku, Chiba-shi, Chiba 263-8555 (Japan); Graduate School of Science and Technology, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba-shi, Chiba 263-8522 (Japan); Ohmura, Atsushi [National Institute of Radiological Sciences, Anagawa 4-9-1 Inage-ku, Chiba-shi, Chiba 263-8555 (Japan); Graduate School of Advanced Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku-ku, Tokyo 169-8555 (Japan); Murayama, Hideo [National Institute of Radiological Sciences, Anagawa 4-9-1 Inage-ku, Chiba-shi, Chiba 263-8555 (Japan)

    2008-01-01

    We are developing a small animal PET scanner, 'jPET-RD' to achieve high sensitivity as well as high spatial resolution by using four-layer depth-of-interaction (DOI) detectors. The jPET-RD is designed with two detector rings. Each detector ring is composed of six DOI detectors arranged hexagonally. The diameter of the field-of-view (FOV) is 8.8 cm, which is smaller than typical small animal PET scanners on the market now. Each detector module consists of a crystal block and a 256-channel flat panel position-sensitive photomultiplier tube. The crystal block, consisting of 32x32x4 crystal (4096 crystals, each 1.46 mmx1.46 mmx4.5 mm) and a reflector, is mounted on the 256ch FP-PMT. In this study, we evaluated the spatial resolution of reconstructed images with the evaluation system of two four-layer DOI detectors which consist of 32x32x4 LYSO (Lu: 98%, Y: 2%) crystals coupled on the 256ch FP-PMT by using RTV rubber. The spatial resolution of 1.5 mm was obtained at the center of the FOV by the filtered back projection. The spatial resolution, better than 2 mm in the whole FOV, was also achieved with DOI while the spatial resolution without DOI was degraded to 3.3 mm.

  1. Evaluating the late career nurse initiative: a cross-sectional survey of senior nurses in Ontario.

    Science.gov (United States)

    Doran, Diane; Jeffs, Lianne; Rizk, Paul; Laporte, Daniel R; Chilcote, Autumn Marie; Bai, Yu Qing

    2015-10-01

    This study evaluated the impact of the late career nurse initiative on nurse perceptions of their work environment, workplace burnout, job satisfaction, organisational commitment and intention to remain. The Ontario Ministry of Health and Long-Term Care introduced the late career nurse initiative with the goal of improving the retention of front-line nurses aged 55 and over by implementing a 0.20 full-time equivalent reduction of physically or psychologically demanding duties, enabling nurses to engage in special projects for the improvement of their organisations and patient care. A sample of 902 nurses aged 55 and over from acute and long-term care facilities were surveyed using valid and reliable questionnaires. Nurses who had participated in the initiative did not differ significantly from those who had not in terms of workplace burnout, job satisfaction, length of service or intention to remain within their current organisation. The late career nurse initiative participants reported significantly higher perceptions of managers' ability, leadership and support and their level of participation in hospital affairs. The late career nurse initiative was associated with perceived differences in nurses' work environment but not outcomes. Leaders need to pay attention to how late career nurses are selected and matched to organisational projects. © 2014 The Authors. Journal of Nursing Management Published by John Wiley & Sons Ltd.

  2. Practical Approaches to Evaluating Progress and Outcomes in Community-Wide Teen Pregnancy Prevention Initiatives.

    Science.gov (United States)

    Tevendale, Heather D; Condron, D Susanne; Garraza, Lucas Godoy; House, L Duane; Romero, Lisa M; Brooks, Megan A M; Walrath, Christine

    2017-03-01

    This paper presents an overview of the key evaluation components for a set of community-wide teen pregnancy prevention initiatives. We first describe the performance measures selected to assess progress toward meeting short-term objectives on the reach and quality of implementation of evidence-based teen pregnancy prevention interventions and adolescent reproductive health services. Next, we describe an evaluation that will compare teen birth rates in intervention communities relative to synthetic control communities. Synthetic controls are developed via a data-driven technique that constructs control communities by combining information from a pool of communities that are similar to the intervention community. Finally, we share lessons learned thus far in the evaluation of the project, with a focus on those lessons that may be valuable for local communities evaluating efforts to reduce teen pregnancy. Copyright © 2016 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  3. A new Slow Control and Run Initialization Byte-wise Environment (SCRIBE) for the quality control of mass-produced CMS GEM detectors

    CERN Document Server

    Colafranceschi, Stefano

    2016-01-01

    The CMS collaboration aims at improving the muon trigger and tracking performance at the HL-LHC by installing new Gas Electron Multiplier (GEM) detectors in the endcaps of the CMS experiment. Construction and commissioning of GEM detectors for the first muon endcap stations is ramping up in several laboratories using common quality control protocols. The SCRIBE framework is a scalable and cross-platform web-based application for the RD51 Scalable Readout System (SRS) that controls data acquisition and analyzes data in near real time. It has been developed mainly to simplify and standardize measurements of the GEM detector response uniformities with x-rays across all production sites. SCRIBE works with zero suppression of raw SRS pulse height data. This has increased acquisition rates to 5 kHz for a CMS GEM detector with 3072 strips and allows strip-by-strip response comparisons with a few hours of data taking. SCRIBE also manages parallel data reconstruction to provide near real-time feedback on the detector ...

  4. Evaluation of a cross-sector community initiative partnership: delivering a local sport program.

    Science.gov (United States)

    Kihl, Lisa A; Tainsky, Scott; Babiak, Kathy; Bang, Hyejin

    2014-06-01

    Corporate community initiatives (CCI) are often established via cross-sector partnerships with nonprofit agencies to address critical social problems. While there is a growing body of literature exploring the effectiveness and social impact of these partnerships, there is a limited evaluative research on the implementation and execution processes of CCIs. In this paper, we examined the implementation and operational processes in the delivery of a professional sport organization's CCI initiative using program theory evaluation. The findings showed discrepancies between the associate organization and the implementers regarding understanding and fulfilling responsibilities with performing certain aspects (maintaining accurate records and program marketing) of the service delivery protocol. Despite program stakeholders being satisfied overall with the program delivery, contradictions between program stakeholders' satisfaction in the quality of program delivery was found in critical components (marketing and communications) of the service delivery. We conclude that ongoing evaluations are necessary to pinpoint the catalyst of the discrepancies along with all partners valuing process evaluation in addition to outcome evaluation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Initial evaluation of children admitted on the Paediatric Intensive Care Unit

    Directory of Open Access Journals (Sweden)

    Esperanza Arce Delgado

    2007-09-01

    Full Text Available The initial evaluation of the child, when admitted on the Paediatric Intensive Unit, is a essential tool and key piece as a starting point on the development of a specific Care Plan for each child. Therefore, it is necessary the existence of a protocol, according to a rigorous methodology, so that cares will have quality and thus, it will be avoided that each nursing professional will act in a different way, according to his intuition, beliefs or improvisation capacity.The initial evaluation of the child will allow us not only to coordinate the interventions, but also to give continuity to the cares.The initial evaluation of the child document is a nursing register that is part of the clinical register of the paediatric patient. Nursing registers turn to be the best approximation of what nowadays is our job’s practice, and they are, therefore, necessary for us to be judged by a professional perspective and to make it possible to classify the services we carry out to the society.

  6. Variability in use of voiding cystourethrogram during initial evaluation of infants with congenital hydronephrosis.

    Science.gov (United States)

    Vemulakonda, Vijaya M; Chiang, George; Corbett, Sean T

    2014-05-01

    To identify geographic variability in the imaging of infants with congenital hydronephrosis at initial pediatric urologic evaluation. We performed a retrospective review of infants aged ≤ 12 months with congenital hydronephrosis seen as new patients from October 2010 to September 2011 at 3 regionally diverse pediatric urology practices: University of Virginia Hospital, Rady Children's Hospital, and Children's Hospital Colorado. Primary outcomes measured were the type and number of tests ordered at initial evaluation. Independent variables collected included the following: patient age, location, and initial ultrasound findings. Ultrasound findings were manually extracted from the attending pediatric urologist's clinic note. All other data were automatically extracted from the electronic medical record. Proportions were analyzed using Pearson's goodness of fit and Fisher exact tests. Medians were compared using the Kruskal-Wallis test. Two hundred forty-one patients met the study criteria. Median patient age was 2 months and did not differ across sites. Most patients (64.7%) had Society for Fetal Urology grade 0-2 hydronephrosis; prevalence of high-grade hydronephrosis varied across sites (P = .002). Use of voiding cystourethrography also varied across sites (17.6%-88.9%); this difference persisted when controlling for age and hydronephrosis grade (P hydronephrosis varies across practices. This variation persists when controlling for differences in age and ultrasound findings, suggesting that regional differences in patient demographics, provider/parental preferences, or referral patterns might contribute to practice variations in the evaluation of these patients. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Initial evaluation of commercial optical CT-based 3D gel dosimeter

    International Nuclear Information System (INIS)

    Islam, K.T.S.; Dempsey, James F.; Ranade, Manisha K.; Maryanski, Marek J.; Low, Daniel A.

    2003-01-01

    We evaluated the OCTOPUS-ONE trade mark sign research laser CT scanner developed and manufactured by MGS Research, Inc. (Madison, CT). The scanner is designed for imaging 3D optical density distributions in BANG registered gels. The scanner operates in a translate-rotate configuration with a single scanning laser beam. The rotating cylindrical gel phantom is immersed in a refractive index matching solution and positioned at the center of a square tank made of plastic and glass. A stationary polarized He-Ne laser beam (633 nm) is reflected from a mirror moving parallel to the tank wall and scans the gel. Another mirror moves synchronously along the opposite side of the tank and collects the transmitted light and sends it to a single stationary silicon photodetector. A filtered backprojection algorithm is used to reconstruct projection data in a plane. The laser-mirrors-detector assembly is mounted on a horizontal platform that moves vertically for slice selection. We have tested the mechanical and optical setup, projection centering on the axis of rotation, linearity, and spatial resolution. We found the optical detector to respond linearly to transmitted light from control samples. The spatial resolution of the scanner was determined by employing a split field resolution technique. We obtained the horizontal and vertical full widths at half maxima of the laser beam intensity profiles as 0.6 and 0.8 mm, respectively. Dose calibration tests of the gel were performed using a nine-field (2x2 cm 2 each) dose pattern irradiated at different dose levels. Finally, we compared gel-derived 2D planar dose distribution against radiochromic film measured dose distribution for both the nine-field and a uniform 5x5 cm 2 field of 6 MV x rays. Very similar dose distributions were observed in gel and radiochromic film except in regions of steep dose gradient and highest dose. A dose normalization of 15.6% was required between the two dosimeters due to differences in overall

  8. An evaluation of electron diamond type EDO2E and EDO3 diamond radiation detectors

    International Nuclear Information System (INIS)

    Poole, D.A.; Wilson, R.

    1977-12-01

    Observations on the response of two d.c. mode (EDO2E) and three pulse mode (EDO3) diamond probes to beta and gamma radiation are reported. In the d.c. mode, response to gamma exposure rates from 1 R h -1 to >6x10 4 R h -1 were measured, currents of approximately 5x10 -13 A and approximately 3x10 -9 A respectively at 20 0 C being observed. The dark current was approximately 3x10 -13 A at 20 0 C and doubled for every 3 to 4 0 C temperature rise. In the pulse mode the count rate was approximately linear with gamma exposure rate from 10 mR h -1 to > 300 R h -1 . The detection of beta particles was limited to energies > or approximately equal 0.8 MeV. Over the temperature range -5 0 C to 50 0 C the count rate for one probe increased by a factor of 1.25 whereas a second probe showed a decrease of 1.4. There is scope for major improvement of diamond detectors as reported by Kozlov et al (1977a) who have eliminated certain undesirable effects by careful selection and the provision of special electrodes. (author)

  9. On-line evaluation of position-sensitive detector (PSD) diffraction data

    International Nuclear Information System (INIS)

    Stansfield, R.F.D.; McIntyre, G.J.

    1985-01-01

    The amount of raw data accumulated in a single-crystal diffraction experiment using a two-dimensional Position Sensitive Detector is usually so large that it is impracticable to store it. It is therefore necessary to reduce each local three-dimensional array of counts to a Bragg intensity, in a time not longer than the average time that one reflection is active. The statistically optimum procedure comprises an estimation of the background from a large number of counts, and an integration of peak intensity within a suitable three-dimensional envelope. A typical on-line method is described, using as an example the D19 diffractometer at the Institut Max von Laue - Paul Langevin (ILL) high-flux reactor. Current methods of PSD data reduction are reviewed. These fall into three groups according to the basis of the method used to find the integration envelope: (a) statistical criteria, (b) three-dimensional sigma(I)/I analysis, and (c) pre-calculation of the resolution function. On-line data reduction imposes special requirements on diagnostics to check the precision of the reduced data, especially at the start of an experiment, when any peculiarities must be identified and allowed for in the data-reduction procedure. The diagnostic possibilities resulting from the comparison of local with global characteristics of the background and the integration envelope are discussed. (author)

  10. Carotid artery wall thickness and ischemic symptoms: evaluation using multi-detector-row CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Saba, Luca; Caddeo, Giancarlo; Mallarini, Giorgio [Azienda Ospedaliero Universitaria Polo di Monserrato, Department of Radiology, Cagliari (Italy); Sanfilippo, Roberto; Montisci, Roberto [Azienda Ospedaliero Universitaria Polo di Monserrato, Department of Vascular Surgery, Cagliari (Italy); Pascalis, Luigi [Azienda Ospedaliero Universitaria Polo di Cagliari, Division of II Internal Medicine, Cagliari (Italy)

    2008-09-15

    The purpose of this study was to determine if carotid artery wall thickness (CAWT) studied by using multi-detector-row CT angiography (MDCTA) can be considered an effective parameter predictive of increased risk of stroke. A total of 217 patients were retrospectively studied by using MDCTA. In all patients CAWT was measured with an internal digital caliper. Continuous data were described as the mean value {+-} standard deviation (SD), and they were compared with Student's t-test. Scatter plots to determine interobserver agreement were performed, and correlation coefficient was calculated with Pearson statistics. A P value <0.05 was considered to mean statistical significance. Measurements of the distal common CAWT ranged from 0.5 to 1.6 mm. In the patient group without stroke, average CAWT was 0.82 mm (0.22 SD), whereas in patient group with stroke it was 1.096 mm (0.21 SD). CAWT in patients without stroke showed statistical difference (P<0.0001) when compared to patients with stroke. By using a threshold of 1 mm, an important statistical association between thick CAWT and stroke was found (P<0.0001). In fact, patients with {>=}1 mm CAWT had stroke with an odds ratio of 8.16 when compared with patients with <1 mm CAWT. Resulting data suggested that an increased CAWT is an indicator for risk of stroke. This parameter should be considered in addition to other well-known risk factors such as diabetes, hypertension, smoking, and dyslipidemia. (orig.)

  11. Evaluation of a SiPM array detector coupled to a LFS-3 pixellated scintillator for PET/MR applications

    Energy Technology Data Exchange (ETDEWEB)

    David, Stratos; Fysikopoulos, Eleftherios [Technological Educational Institute of Athens (Greece); Georgiou, Maria [Technological Educational Institute of Athens (Greece); Department of Medical School, University of Thessaly, Larissa (Greece); Loudos, George [Technological Educational Institute of Athens (Greece)

    2015-05-18

    SiPM arrays are insensitive to magnetic fields and thus good candidates for hybrid PET/MR imaging systems. Moreover, due to their small size and flexibility can be used in dedicated small field of view small animal imaging detectors and especially in head PET/MR studies in mice. Co-doped LFS-3 scintillator crystals have higher light yield and slightly faster response than that of LSO:Ce mainly due to the co-doped activation of emission centers with varying materials such as Ce, Gd, Sc, Y, La, Tb, or Ca distributed at the molecular scale through the lutetium silicate crystal host. The purpose of this study is to investigate the behavior of the SensL ArraySL-4 (4x4 element array of 3x3 mm{sup 2} silicon photomultipliers) optical detector coupled to a 6x6 LFS-3 scintillator array, with 2x2x5 mm{sup 3} crystal size elements, for possible applications in small field of view PET/MR imaging detectors. We have designed a symmetric resistive charge division circuit to read out the signal outputs of 4x4 pixel SiPM array reducing the 16 pixel outputs of the photodetector to 4 position signals. The 4 position signals were digitized using free running Analog to Digital Converters. The ADCs sampling rate was 50 MHz. An FPGA (Spartan 6 LX150T) was used for triggering and digital signal processing of the pulses. Experimental evaluation was carried out with {sup 22}Na radioactive source and the parameters studied where energy resolution and peak to valley ratio. The first preliminary results of the evaluation shows a clear visualization of the discrete 2x2x5 mm{sup 3} LFS-3 scintillator elements. The mean peak to valley ratio of the horizontal profiles on the raw image was measured equal to 11 while the energy resolution was calculated equal to 30% at the central pixels.

  12. Evaluation of imaging quality for flat-panel detector based low dose C-arm CT system

    International Nuclear Information System (INIS)

    Seo, Chang-Woo; Cha, Bo Kyung; Jeon, Sungchae; Huh, Young

    2015-01-01

    The image quality associated with the extent of the angle of gantry rotation, the number of projection views, and the dose of X-ray radiation was investigated in flat-panel detector (FPD) based C-arm cone-beam computed tomography (CBCT) system for medical applications. A prototype CBCT system for the projection acquisition used the X-ray tube (A-132, Varian inc.) having rhenium-tungsten molybdenum target and flat panel a-Si X-ray detector (PaxScan 4030CB, Varian inc.) having a 397 x 298 mm active area with 388 μm pixel pitch and 1024 x 768 pixels in 2 by 2 binning mode. The performance comparison of X-ray imaging quality was carried out using the Feldkamp, Davis, and Kress (FDK) reconstruction algorithm between different conditions of projection acquisition. In this work, head-and-dental (75 kVp/20 mA) and chest (90 kVp/25 mA) phantoms were used to evaluate the image quality. The 361 (30 fps x 12 s) projection data during 360 deg. gantry rotation with 1 deg. interval for the 3D reconstruction were acquired. Parke weighting function were applied to handle redundant data and improve the reconstructed image quality in a mobile C-arm system with limited rotation angles. The reconstructed 3D images were investigated for comparison of qualitative image quality in terms of scan protocols (projection views, rotation angles and exposure dose). Furthermore, the performance evaluation in image quality will be investigated regarding X-ray dose and limited projection data for a FPD based mobile C-arm CBCT system. (authors)

  13. Evaluation of a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography of scaphoid fixation screws

    Energy Technology Data Exchange (ETDEWEB)

    Filli, Lukas; Finkenstaedt, Tim; Andreisek, Gustav; Guggenberger, Roman [University Hospital of Zurich, Department of Diagnostic and Interventional Radiology, Zurich (Switzerland); Marcon, Magda [University Hospital of Zurich, Department of Diagnostic and Interventional Radiology, Zurich (Switzerland); University of Udine, Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, Udine (Italy); Scholz, Bernhard [Imaging and Therapy Division, Siemens AG, Healthcare Sector, Forchheim (Germany); Calcagni, Maurizio [University Hospital of Zurich, Division of Plastic Surgery and Hand Surgery, Zurich (Switzerland)

    2014-12-15

    The aim of this study was to evaluate a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography (FDCT) of scaphoid fixation screws. FDCT has gained interest in imaging small anatomic structures of the appendicular skeleton. Angiographic C-arm systems with flat detectors allow fluoroscopy and FDCT imaging in a one-stop procedure emphasizing their role as an ideal intraoperative imaging tool. However, FDCT imaging can be significantly impaired by artefacts induced by fixation screws. Following ethical board approval, commercially available scaphoid fixation screws were inserted into six cadaveric specimens in order to fix artificially induced scaphoid fractures. FDCT images corrected with the algorithm were compared to uncorrected images both quantitatively and qualitatively by two independent radiologists in terms of artefacts, screw contour, fracture line visibility, bone visibility, and soft tissue definition. Normal distribution of variables was evaluated using the Kolmogorov-Smirnov test. In case of normal distribution, quantitative variables were compared using paired Student's t tests. The Wilcoxon signed-rank test was used for quantitative variables without normal distribution and all qualitative variables. A p value of < 0.05 was considered to indicate statistically significant differences. Metal artefacts were significantly reduced by the correction algorithm (p < 0.001), and the fracture line was more clearly defined (p < 0.01). The inter-observer reliability was ''almost perfect'' (intra-class correlation coefficient 0.85, p < 0.001). The prototype correction algorithm in FDCT for metal artefacts induced by scaphoid fixation screws may facilitate intra- and postoperative follow-up imaging. (orig.)

  14. Evaluation of a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography of scaphoid fixation screws

    International Nuclear Information System (INIS)

    Filli, Lukas; Finkenstaedt, Tim; Andreisek, Gustav; Guggenberger, Roman; Marcon, Magda; Scholz, Bernhard; Calcagni, Maurizio

    2014-01-01

    The aim of this study was to evaluate a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography (FDCT) of scaphoid fixation screws. FDCT has gained interest in imaging small anatomic structures of the appendicular skeleton. Angiographic C-arm systems with flat detectors allow fluoroscopy and FDCT imaging in a one-stop procedure emphasizing their role as an ideal intraoperative imaging tool. However, FDCT imaging can be significantly impaired by artefacts induced by fixation screws. Following ethical board approval, commercially available scaphoid fixation screws were inserted into six cadaveric specimens in order to fix artificially induced scaphoid fractures. FDCT images corrected with the algorithm were compared to uncorrected images both quantitatively and qualitatively by two independent radiologists in terms of artefacts, screw contour, fracture line visibility, bone visibility, and soft tissue definition. Normal distribution of variables was evaluated using the Kolmogorov-Smirnov test. In case of normal distribution, quantitative variables were compared using paired Student's t tests. The Wilcoxon signed-rank test was used for quantitative variables without normal distribution and all qualitative variables. A p value of < 0.05 was considered to indicate statistically significant differences. Metal artefacts were significantly reduced by the correction algorithm (p < 0.001), and the fracture line was more clearly defined (p < 0.01). The inter-observer reliability was ''almost perfect'' (intra-class correlation coefficient 0.85, p < 0.001). The prototype correction algorithm in FDCT for metal artefacts induced by scaphoid fixation screws may facilitate intra- and postoperative follow-up imaging. (orig.)

  15. Automated electronic intruder simulator for evaluation of odd frequency microwave detectors

    International Nuclear Information System (INIS)

    1979-01-01

    A microwave intruder simulator for testing motion detection sensors is described. This simulator can be used to evaluate a variety of microwave sensors regardless of the value of the center frequency of the signal utilized. Representative curves from the evaluation of one microwave sensor are also presented

  16. Anterior prostate biopsy at initial and repeat evaluation: is it useful to detect significant prostate cancer?

    Directory of Open Access Journals (Sweden)

    Pietro Pepe

    2015-10-01

    Full Text Available ABSTRACT Purpose: Detection rate for anterior prostate cancer (PCa in men who underwent initial and repeat biopsy has been prospectively evaluated. Materials and Methods: From January 2013 to March 2014, 400 patients all of Caucasian origin (median age 63.5 years underwent initial (285 cases and repeat (115 cases prostate biopsy; all the men had negative digital rectal examination and the indications to biopsy were: PSA values > 10 ng/mL, PSA between 4.1-10 or 2.6-4 ng/mL with free/total PSA≤25% and ≤20%, respectively. A median of 22 (initial biopsy and 31 cores (repeat biopsy were transperineally performed including 4 cores of the anterior zone (AZ and 4 cores of the AZ plus 2 cores of the transition zone (TZ, respectively. Results: Median PSA was 7.9 ng/mL; overall, a PCa was found in 180 (45% patients: in 135 (47.4% and 45 (36% of the men who underwent initial and repeat biopsy, respectively. An exclusive PCa of the anterior zone was found in the 8.9 (initial biopsy vs 13.3% (repeat biopsy of the men: a single microfocus of cancer was found in the 61.2% of the cases; moreover, in 7 out 18 AZ PCa the biopsy histology was predictive of significant cancer in 2 (28.5% and 5 (71.5% men who underwent initial and repeat biopsy, respectively. Conclusions: However AZ biopsies increased detection rate for PCa (10% of the cases, the majority of AZ PCa with histological findings predictive of clinically significant cancer were found at repeat biopsy (about 70% of the cases.

  17. Carotid artery wall thickness and ischemic symptoms: evaluation using multi-detector-row CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Saba, Luca; Caddeo, Giancarlo; Mallarini, Giorgio [Azienda Ospedaliero Universitaria Polo di Monserrato, Department of Radiology, Cagliari (Italy); Sanfilippo, Roberto; Montisci, Roberto [Azienda Ospedaliero Universitaria Polo di Monserrato, Department of Vascular Surgery, Cagliari (Italy); Pascalis, Luigi [Azienda Ospedaliero Universitaria Polo di Cagliari, Division of II Internal Medicine, Cagliari (Italy)

    2008-09-15

    The purpose of this study was to determine if carotid artery wall thickness (CAWT) studied by using multi-detector-row CT angiography (MDCTA) can be considered an effective parameter predictive of increased risk of stroke. A total of 217 patients were retrospectively studied by using MDCTA. In all patients CAWT was measured with an internal digital caliper. Continuous data were described as the mean value {+-} standard deviation (SD), and they were compared with Student's t-test. Scatter plots to determine interobserver agreement were performed, and correlation coefficient was calculated with Pearson statistics. A P value <0.05 was considered to mean statistical significance. Measurements of the distal common CAWT ranged from 0.5 to 1.6 mm. In the patient group without stroke, average CAWT was 0.82 mm (0.22 SD), whereas in patient group with stroke it was 1.096 mm (0.21 SD). CAWT in patients without stroke showed statistical difference (P<0.0001) when compared to patients with stroke. By using a threshold of 1 mm, an important statistical association between thick CAWT and stroke was found (P<0.0001). In fact, patients with {>=}1 mm CAWT had stroke with an odds ratio of 8.16 when compared with patients with <1 mm CAWT. Resulting data suggested that an increased CAWT is an indicator for risk of stroke. This parameter should be considered in addition to other well-known risk factors such as diabetes, hypertension, smoking, and dyslipidemia. (orig.)

  18. Carotid artery wall thickness and ischemic symptoms: evaluation using multi-detector-row CT angiography

    International Nuclear Information System (INIS)

    Saba, Luca; Caddeo, Giancarlo; Mallarini, Giorgio; Sanfilippo, Roberto; Montisci, Roberto; Pascalis, Luigi

    2008-01-01

    The purpose of this study was to determine if carotid artery wall thickness (CAWT) studied by using multi-detector-row CT angiography (MDCTA) can be considered an effective parameter predictive of increased risk of stroke. A total of 217 patients were retrospectively studied by using MDCTA. In all patients CAWT was measured with an internal digital caliper. Continuous data were described as the mean value ± standard deviation (SD), and they were compared with Student's t-test. Scatter plots to determine interobserver agreement were performed, and correlation coefficient was calculated with Pearson statistics. A P value <0.05 was considered to mean statistical significance. Measurements of the distal common CAWT ranged from 0.5 to 1.6 mm. In the patient group without stroke, average CAWT was 0.82 mm (0.22 SD), whereas in patient group with stroke it was 1.096 mm (0.21 SD). CAWT in patients without stroke showed statistical difference (P<0.0001) when compared to patients with stroke. By using a threshold of 1 mm, an important statistical association between thick CAWT and stroke was found (P<0.0001). In fact, patients with ≥1 mm CAWT had stroke with an odds ratio of 8.16 when compared with patients with <1 mm CAWT. Resulting data suggested that an increased CAWT is an indicator for risk of stroke. This parameter should be considered in addition to other well-known risk factors such as diabetes, hypertension, smoking, and dyslipidemia. (orig.)

  19. Evaluation of the influence of parameters that determine the mean glandular dose in mammography using different detectors; Evaluacion de la influencia de los parametros que determinan la dosis glandular media en Mamografia utilizando diferentes detectores

    Energy Technology Data Exchange (ETDEWEB)

    Costa, K.; Nogueira, M. S., E-mail: katicostabh@gmail.com [Centro de Desenvolvimento da Tecnologia Nuclear, Pos-graduacao em Ciencias e Tecnologia das Radiacoes, Minerais e Materiais / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

    2015-10-15

    Full text: Mammography is a test used for early detection of breast cancer. The mean glandular dose (MGD) is dosimetric greatness accepted as indicative of carcinogenic risk induced by ionizing radiation in the breasts of women undergoing mammography exams. MGD value is estimated from the incident air kerma (k i), associated with conversion factors which depend on the half-value layer (HVL), the breast composition and thickness compressed breast. This study aims to evaluate the influence of the parameters used to determine the MGD using different measurement detectors. Measurements were performed on a Siemens Mammomat Model 300 Nova mammography equipment; this has the combinations Anode/Filter of Mo/Mo, Mo/Rh and W/Rh. Detectors used were the ionization chamber Model 10X6-6M manufactured by Radcal Co., two solid-state detectors, one Model AGMS-M manufactured by Radcal Co. and other Model Xi Mammo manufactured by UNFORS. The detectors measures were compared and the MGD value was estimated; differences between measurements and the reference values were higher in HVL and k i parameters. The results are displayed according to other published works. (Author)

  20. Initial assessment of hearing loss using a mobile application for audiological evaluation.

    Science.gov (United States)

    Derin, S; Cam, O H; Beydilli, H; Acar, E; Elicora, S S; Sahan, M

    2016-03-01

    This study aimed to compare an Apple iOS mobile operating system application for audiological evaluation with conventional audiometry, and to determine its accuracy and reliability in the initial evaluation of hearing loss. The study comprised 32 patients (16 females) diagnosed with hearing loss. The patients were first evaluated with conventional audiometry and the degree of hearing loss was recorded. Then they underwent a smartphone-based hearing test and the data were compared using Cohen's kappa analysis. Patients' mean age was 53.59 ± 18.01 years (range, 19-85 years). The mobile phone audiometry results for 39 of the 64 ears were fully compatible with the conventional audiometry results. There was a statistically significant concordant relationship between the two sets of audiometry results (p Apple iPhone 5 that can measure hearing loss with reliable results.

  1. Initial quantitative evaluation of computed radiography in an intensive care unit

    International Nuclear Information System (INIS)

    Hillis, D.J.; McDonald, I.G.; Kelly, W.J.

    1996-01-01

    The first computed radiography (CR) unit in Australia was installed at St Vincent's Hospital, Melbourne, in February 1994. An initial qualitative evaluation of the attitude of the intensive care unit (ICU) physicians to the CR unit was conducted by use of a survey. The results of the survey of ICU physicians indicated that images were available faster than under the previous system and that the use of the CR system was preferred to evaluate chest tubes and line placements. While it is recognized that a further detailed radiological evaluation of the CR system is required to establish the diagnostic performance of CR compared with conventional film, some comments on the implementation of the system and ICU physician attitudes to the CR system are put forward for consideration by other hospitals examining the possible use of CR systems. 11 refs., 1 tab

  2. Evaluation of an unshielded luminescence flow-through radio-HPLC detector for LC quality control and preparation of PET radiopharmaceuticals

    International Nuclear Information System (INIS)

    Thonon, David; Kaisin, Geoffroy; Henrottin, Jean; Aerts, Joël; Van Malderen, Hans; Luxen, André

    2013-01-01

    Radio-HPLC is an essential method to assess the purity of PET radiopharmaceuticals. The usual NaI scintillator radiodetector requires heavy, costly and cumbersome lead shielding. The luminescence LB 500 fLumo detector has been developed to tackle these drawbacks and achieve high sensitivity. The fLumo uses a photon counting detector combined with a flow-through cell modified with a solid melt-on scintillator only sensitive to the positron. This study demonstrates the usefulness of the fLumo for analysis and purification of PET radiopharmaceuticals. - Highlights: ► We evaluate a novel unshielded luminescence flow-through radio-HPLC detector (fLumo) which is only sensitive to the positron and insensitive to gamma rays for applications in PET radiopharmaceuticals analysis and preparation. ► The fLumo detector exhibits a low limit of detection as activities as low as 4 kBq are detected (HPLC and UPLC radiodetectors). ► The fLumo detector demonstrates excellent linearity (0.2 to 2500 MBq/ml, r 2 >0.995) and reproducibility. ► Thanks to its compactness and absence of shielding, the fLumo has been installed in a production shielded “hot” cell to detect radiocompounds during a semi-preparative HPLC purification. ► This work demonstrates the value of the fLumo luminescence flow-through radio-HPLC detector for applications in PET tracers radiochemistry

  3. Design and development of an anthropomorphic phantom equipped with detectors in order to evaluate the effective dose E at workplaces: feasibility study

    International Nuclear Information System (INIS)

    Furstoss, Ch.

    2006-11-01

    My PhD study aims to determine the feasibility to design and develop, for photon fields, an anthropomorphic phantom equipped with detectors in order to evaluate the effective dose E at workplaces. First of all, the energy losses within the organs are calculated using the M.C.N.P.X. Monte Carlo code, in order to determine the detection positions within the different organs. Then, to decrease the number of detection positions, the organ contribution to the effective dose is studied. Finally, the characteristics of the detectors to insert and the characteristics of the phantom to use are deduced. The results show that 24 or 23 detection positions, according to the wT values (publication 60 or new recommendations of the ICRP), give a E estimation with an uncertainty of ±15 % from 50 keV to 4 MeV. Moreover, the interest of such an instrument is underlined while comparing the E estimation by the personal dose equivalent Hp to the E estimation by the instrumented phantom when the phantom is irradiated by point sources (worker in front of a glove box for example). Last, after the detector and phantom characteristic determination, two types of detectors and one type of phantom are selected. However, for the detectors mainly, developments are necessary. Follow up this study, the characterization and the adaptation of the detectors to the project would be interesting. Furthermore, the study to mixed photon-neutrons would be required the needs of the radiological protection community. (author)

  4. Evaluation of Fatigue Crack Initiation for Volumetric Flaw in Pressure Tube

    International Nuclear Information System (INIS)

    Choi, Sung Nam; Yoo, Hyun Joo

    2005-01-01

    CAN/CSA.N285.4-94 requires the periodic inservice inspection and surveillance of pressure tubes in operating CANDU nuclear power reactors. If the inspection results reveal a flaw exceeding the acceptance criteria of the Code, the flaw must be evaluated to determine if the pressure is acceptable for continued service. Currently, the flaw evaluation methodology and acceptance criteria specified in CSA-N285.05-2005, 'Technical requirements for in-service evaluation of zirconium alloy pressure tubes in CANDU reactors'. The Code is applicable to zirconium alloy pressure tubes. The evaluation methodology for a crack-like flaw is similar to that of ASME B and PV Sec. XI, 'Inservice Inspection of Nuclear Power Plant Components'. However, the evaluation methodology for a blunt volumetric flaw is described in CSA-N285.05-2005 code. The object of this paper is to address the fatigue crack initiation evaluation for the blunt volumetric flaw as it applies to the pressure tube at Wolsong NPP

  5. A anatomic evaluation of the lateral femoral circumflex artery system by using Multi detector-row CT

    International Nuclear Information System (INIS)

    Haraguchi, Kazunari; Kadota, Satoshi; Hosaka, Yoshiaki

    2010-01-01

    Flaps that are pedicled by perforators of the lateral femoral circumflex artery (LFCA) system have many advantages, including the transplantation of large and reliable skin with long pedicles and a large diameter, and little invasion of the donor sites. However, preoperative planning has been difficult because the perforators have many anatomic variations. We used multi detector-row CT for anatomical evaluation of the lateral femoral circumflex artery system. The patterns of LFCA from the main vessels were classified into three types and vessels coursing toward the lateral thigh region were classified into three groups. The distance from the anterior superior iliac spine to the lateral femoral circumflex artery showed no significant difference between men and women. We were able to evaluate vessels with a 2-mm diameter in the lateral femoral circumflex artery system, indicating that accurate evaluation and low invasive examination of the lateral femoral circumflex artery system, including the perforator area, can be achieved by adjusting the image conditions and the injection rate of the contrast dye. (author)

  6. Clinical evaluation of digital angiographic system equipped with the Safire' flat-panel detector of a direct conversion type

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Yoshiaki; Miura, Yusuke; Goto, Keiichi [Shimadzu Corporation, Medical Systems Division, Research and Development, Kyoto (JP)] [and others

    2003-06-01

    This report presents a report on clinical evaluation of our newly developed flat-panel X-ray detector of a direct conversion type, designed to provide images of a resolution higher than, or at least equal to, that ensured by X-ray photographic films, in clinical digital X-ray cinematography. This new detector was named 'Safire' the acronym of 'Shimadzu advanced flat imaging receptor', emphasizing its high technological level, such as the capability to ensure high quality of images. The clinical evaluation of Shimadzu DIGITEX Premier digital angiography system, equipped with this new flat-panel X-ray detector of a direct conversion type, has been started in March, 2003, at the Kokura Memorial Hospital in Kyushu, Japan. (author)

  7. Evaluation of patient exposure with Flat Panel Detector (FPD) in X-ray TV system

    International Nuclear Information System (INIS)

    Yamada, M.; Komiya, N.; Kawaguchi, A.; Suzuki, M.; Suzuki, Shoichi; Asada, Yasuki

    2008-01-01

    The use of flat-panel detector (FPD) systems in TV equipment for gastrointestinal tract examination is increasing. The use of FPD systems is believed to reduce the exposure dose. When our institution changed its TV equipment from an image intensifier (GE; MS90Tj) system to an FPD (Shimadzu; SONIALVISION safire DAR-3500) system, we measured the doses produced and carried out a comparative examination of the extent to which exposure could be reduced. Two TV systems were used. We used an analyzer to measure output waveform, tube voltage, and half-value layer (HVL), and an ionization chamber dosimeter to carry out dose-in-air measurements. Body thickness, number of image acquisitions, and fluoroscopy time are required for the calculation of entrance skin dose (ESD). We therefore measured body thicknesses in 1000 upper gastrointestinal tract (UGI) and barium enemas and obtained average body thicknesses for males and females by age group. Values used for number of image acquisitions and fluoroscopy times were the averages in our institution over a two-year period. When an I.I. system was used, the average ESD during UGI examination were 126.8 mGy fluoroscopy dose and 11.62 mGy imaging dose, for an average total dose of 138.42 mGy per examination. ESD during barium enema averaged 201.73 mGy fluoroscopy dose and 45.2 mGy imaging dose, for an average total dose of 246.92 mGy per examination. When an FPD system was used, the average ESD during UGI examination were 58.71 mGy fluoroscopy dose and 5.72 mGy imaging dose, for an average total dose of 64.43 mGy per examination. ESD during barium enema averaged 112.21 mGy fluoroscopy dose and 24.55 mGy imaging dose, for an average total dose of 136.76 mGy per examination. The use of an FPD system reduced both fluoroscopy dose and imaging dose by 50%. The number of TV systems equipped with FPD in Japan has increased from around 1300 in 2006 to around 1700 in 2007. The use of FPD systems can be expected to increase in future. This

  8. Performance evaluation of a fully depleted monolithic pixel detector chip in 150 nm CMOS technology

    Energy Technology Data Exchange (ETDEWEB)

    Obermann, Theresa

    2017-06-15

    The depleted monolithic active pixel sensor (DMAPS) is a new concept integrating full CMOS circuitry onto a (fully) depletable silicon substrate wafer. The realization of prototypes of the DMAPS concept relies on the availability of multiple well CMOS processes and highly resistive substrates. The CMOS foundry ESPROS Photonics offers both and was chosen for prototyping. Two prototypes, EPCB01 and EPCB02, developed in a 150 nm process on a highly resistive n-type wafer of 50 μm thickness, were characterized. The prototypes have 352 square pixels of 40 μm pitch and a small n-well charge collection node with very low capacitance of 5 fF (n{sup +}-implantation size: 5 μm x 5 μm) and about 150 transistors per pixel (CSA and discriminator plus a small digital part). The characterization of the prototypes demonstrates the proof of principle of the concept. Prior to irradiation the prototypes show a signal from a minimum ionizing particle ranging from 2400 e{sup -} to 3000 e{sup -} while the noise is 30 e{sup -} due to the low capacitance. After the irradiation of the prototypes with neutrons up to a fluence of 5 x 10{sup 14} neutrons/cm{sup 2} the performance suffers from the radiation damage leading to a signal of 1000 e{sup -} and a higher noise of 60 e{sup -} due to the increase of the leakage current. The detection efficiency of the prototypes reduces from 94 % to 26 % after the fluence of 5 x 10{sup 14} particles/cm{sup 2}. Due to the small fill factor the detection efficiency shows are strong dependence on the position within the pixel after irradiation. Thus the DMAPS concept with low fill factor can be used for precise vertex reconstruction in High Energy Physics experiments without severe performance loss up to moderate fluences (< 1 x 10{sup 14} particles/cm{sup 2}). The expected particle fluences inside of the volume of the upgrade of the ATLAS pixel detector exceed this limit. However, possible applications could be at future linear collider (ILC or CLIC

  9. Performance evaluation of a fully depleted monolithic pixel detector chip in 150 nm CMOS technology

    International Nuclear Information System (INIS)

    Obermann, Theresa

    2017-06-01

    The depleted monolithic active pixel sensor (DMAPS) is a new concept integrating full CMOS circuitry onto a (fully) depletable silicon substrate wafer. The realization of prototypes of the DMAPS concept relies on the availability of multiple well CMOS processes and highly resistive substrates. The CMOS foundry ESPROS Photonics offers both and was chosen for prototyping. Two prototypes, EPCB01 and EPCB02, developed in a 150 nm process on a highly resistive n-type wafer of 50 μm thickness, were characterized. The prototypes have 352 square pixels of 40 μm pitch and a small n-well charge collection node with very low capacitance of 5 fF (n + -implantation size: 5 μm x 5 μm) and about 150 transistors per pixel (CSA and discriminator plus a small digital part). The characterization of the prototypes demonstrates the proof of principle of the concept. Prior to irradiation the prototypes show a signal from a minimum ionizing particle ranging from 2400 e - to 3000 e - while the noise is 30 e - due to the low capacitance. After the irradiation of the prototypes with neutrons up to a fluence of 5 x 10 14 neutrons/cm 2 the performance suffers from the radiation damage leading to a signal of 1000 e - and a higher noise of 60 e - due to the increase of the leakage current. The detection efficiency of the prototypes reduces from 94 % to 26 % after the fluence of 5 x 10 14 particles/cm 2 . Due to the small fill factor the detection efficiency shows are strong dependence on the position within the pixel after irradiation. Thus the DMAPS concept with low fill factor can be used for precise vertex reconstruction in High Energy Physics experiments without severe performance loss up to moderate fluences (< 1 x 10 14 particles/cm 2 ). The expected particle fluences inside of the volume of the upgrade of the ATLAS pixel detector exceed this limit. However, possible applications could be at future linear collider (ILC or CLIC) experiments and B-factories where the low material budget

  10. Evaluation of the Healthy Lifestyles Initiative for Improving Community Capacity for Childhood Obesity Prevention.

    Science.gov (United States)

    Berman, Marcie; Bozsik, Frances; Shook, Robin P; Meissen-Sebelius, Emily; Markenson, Deborah; Summar, Shelly; DeWit, Emily; Carlson, Jordan A

    2018-02-22

    Policy, systems, and environmental approaches are recommended for preventing childhood obesity. The objective of our study was to evaluate the Healthy Lifestyles Initiative, which aimed to strengthen community capacity for policy, systems, and environmental approaches to healthy eating and active living among children and families. The Healthy Lifestyles Initiative was developed through a collaborative process and facilitated by community organizers at a local children's hospital. The initiative supported 218 partners from 170 community organizations through training, action planning, coalition support, one-on-one support, and the dissemination of materials and sharing of resources. Eighty initiative partners completed a brief online survey on implementation strategies engaged in, materials used, and policy, systems, and environmental activities implemented. In accordance with frameworks for implementation science, we assessed associations among the constructs by using linear regression to identify whether and which of the implementation strategies were associated with materials used and implementation of policy, systems, and environmental activities targeted by the initiative. Each implementation strategy was engaged in by 30% to 35% of the 80 survey respondents. The most frequently used materials were educational handouts (76.3%) and posters (66.3%). The most frequently implemented activities were developing or continuing partnerships (57.5%) and reviewing organizational wellness policies (46.3%). Completing an action plan and the number of implementation strategies engaged in were positively associated with implementation of targeted activities (action plan, effect size = 0.82; number of strategies, effect size = 0.51) and materials use (action plan, effect size = 0.59; number of strategies, effect size = 0.52). Materials use was positively associated with implementation of targeted activities (effect size = 0.35). Community-capacity-building efforts can be

  11. Experimental evaluation of scattered thermal neutrons from various jig materials for use in fixing detectors for the calibration

    International Nuclear Information System (INIS)

    Shimizu, Shigeru; Yoshizawa, Michio

    2000-05-01

    Some jigs to fix detectors are used when radiation measuring instruments are calibrated or reference fluence rates are measured in thermal neutron irradiation fields. In this case, scattered thermal neutrons from the jigs, in particular, which contain hydrogenous materials, may affect the results of the calibration and measurements. In this study, scattered thermal neutrons were measured and calculated to clarify the characteristics of the thermal neutron scattered from various materials which are frequently used for the jigs. A spherical BF 3 -counter of 2-inches in diameter was used in the experiment. Ratios of the fluence of scattered neutrons to primaries (hereinafter, scattering ratio) were evaluated as a function of thickness and size of the materials, as well as the distance from the surface of the materials. The scattering ratios of the jigs that were actually-used in the calibration were also measured in order to select appropriate materials and thickness for the jigs. It was found that the scattering ratios were saturated with increase of thickness and size of the materials. The higher values were observed in the case of PMMA (polymethylmethacrylates) and paraffin since these materials contain more number of hydrogen atoms than the others. The saturated value was obtained 130% for PMMA and paraffin with the thickness of more than 5 cm and the size of 40 cm x 40 cm. The results for the actually-used jigs show that the thinner plate of styrofoam and aluminum reduces the scattering ratio to the value of less than 1%. The obtained data will be useful to improve the accuracy of the calibration of thermal neutron detectors and the measurement of reference fluence rates in thermal neutron irradiation fields. (author)

  12. Experimental evaluation of scattered thermal neutrons from various jig materials for use in fixing detectors for the calibration

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Shigeru; Yoshizawa, Michio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nemoto, Hisashi; Kurosawa, Koji [Institute of Radiation Measurement, Tokai, Ibaraki (Japan)

    2000-05-01

    Some jigs to fix detectors are used when radiation measuring instruments are calibrated or reference fluence rates are measured in thermal neutron irradiation fields. In this case, scattered thermal neutrons from the jigs, in particular, which contain hydrogenous materials, may affect the results of the calibration and measurements. In this study, scattered thermal neutrons were measured and calculated to clarify the characteristics of the thermal neutron scattered from various materials which are frequently used for the jigs. A spherical BF{sub 3}-counter of 2-inches in diameter was used in the experiment. Ratios of the fluence of scattered neutrons to primaries (hereinafter, scattering ratio) were evaluated as a function of thickness and size of the materials, as well as the distance from the surface of the materials. The scattering ratios of the jigs that were actually-used in the calibration were also measured in order to select appropriate materials and thickness for the jigs. It was found that the scattering ratios were saturated with increase of thickness and size of the materials. The higher values were observed in the case of PMMA (polymethylmethacrylates) and paraffin since these materials contain more number of hydrogen atoms than the others. The saturated value was obtained 130% for PMMA and paraffin with the thickness of more than 5 cm and the size of 40 cm x 40 cm. The results for the actually-used jigs show that the thinner plate of styrofoam and aluminum reduces the scattering ratio to the value of less than 1%. The obtained data will be useful to improve the accuracy of the calibration of thermal neutron detectors and the measurement of reference fluence rates in thermal neutron irradiation fields. (author)

  13. Evaluation of conventional imaging performance in a research whole-body CT system with a photon-counting detector array

    International Nuclear Information System (INIS)

    Yu, Zhicong; Leng, Shuai; Li, Zhoubo; Chen, Baiyu; Yu, Lifeng; McCollough, Cynthia H; Jorgensen, Steven M; Ritman, Erik L; Gutjahr, Ralf; Kappler, Steffen; Halaweish, Ahmed F

    2016-01-01

    This study evaluated the conventional imaging performance of a research whole-body photon-counting CT system and investigated its feasibility for imaging using clinically realistic levels of x-ray photon flux. This research system was built on the platform of a 2nd generation dual-source CT system: one source coupled to an energy integrating detector (EID) and the other coupled to a photon-counting detector (PCD). Phantom studies were conducted to measure CT number accuracy and uniformity for water, CT number energy dependency for high-Z materials, spatial resolution, noise, and contrast-to-noise ratio. The results from the EID and PCD subsystems were compared. The impact of high photon flux, such as pulse pile-up, was assessed by studying the noise-to-tube-current relationship using a neonate water phantom and high x-ray photon flux. Finally, clinical feasibility of the PCD subsystem was investigated using anthropomorphic phantoms, a cadaveric head, and a whole-body cadaver, which were scanned at dose levels equivalent to or higher than those used clinically. Phantom measurements demonstrated that the PCD subsystem provided comparable image quality to the EID subsystem, except that the PCD subsystem provided slightly better longitudinal spatial resolution and about 25% improvement in contrast-to-noise ratio for iodine. The impact of high photon flux was found to be negligible for the PCD subsystem: only subtle high-flux effects were noticed for tube currents higher than 300 mA in images of the neonate water phantom. Results of the anthropomorphic phantom and cadaver scans demonstrated comparable image quality between the EID and PCD subsystems. There were no noticeable ring, streaking, or cupping/capping artifacts in the PCD images. In addition, the PCD subsystem provided spectral information. Our experiments demonstrated that the research whole-body photon-counting CT system is capable of providing clinical image quality at clinically realistic levels of x

  14. Evaluation of conventional imaging performance in a research whole-body CT system with a photon-counting detector array.

    Science.gov (United States)

    Yu, Zhicong; Leng, Shuai; Jorgensen, Steven M; Li, Zhoubo; Gutjahr, Ralf; Chen, Baiyu; Halaweish, Ahmed F; Kappler, Steffen; Yu, Lifeng; Ritman, Erik L; McCollough, Cynthia H

    2016-02-21

    This study evaluated the conventional imaging performance of a research whole-body photon-counting CT system and investigated its feasibility for imaging using clinically realistic levels of x-ray photon flux. This research system was built on the platform of a 2nd generation dual-source CT system: one source coupled to an energy integrating detector (EID) and the other coupled to a photon-counting detector (PCD). Phantom studies were conducted to measure CT number accuracy and uniformity for water, CT number energy dependency for high-Z materials, spatial resolution, noise, and contrast-to-noise ratio. The results from the EID and PCD subsystems were compared. The impact of high photon flux, such as pulse pile-up, was assessed by studying the noise-to-tube-current relationship using a neonate water phantom and high x-ray photon flux. Finally, clinical feasibility of the PCD subsystem was investigated using anthropomorphic phantoms, a cadaveric head, and a whole-body cadaver, which were scanned at dose levels equivalent to or higher than those used clinically. Phantom measurements demonstrated that the PCD subsystem provided comparable image quality to the EID subsystem, except that the PCD subsystem provided slightly better longitudinal spatial resolution and about 25% improvement in contrast-to-noise ratio for iodine. The impact of high photon flux was found to be negligible for the PCD subsystem: only subtle high-flux effects were noticed for tube currents higher than 300 mA in images of the neonate water phantom. Results of the anthropomorphic phantom and cadaver scans demonstrated comparable image quality between the EID and PCD subsystems. There were no noticeable ring, streaking, or cupping/capping artifacts in the PCD images. In addition, the PCD subsystem provided spectral information. Our experiments demonstrated that the research whole-body photon-counting CT system is capable of providing clinical image quality at clinically realistic levels of x

  15. Evaluation of linear array MOSFET detectors for in vivo dosimetry to measure rectal dose in HDR brachytherapy.

    Science.gov (United States)

    Haughey, Aisling; Coalter, George; Mugabe, Koki

    2011-09-01

    The study aimed to assess the suitability of linear array metal oxide semiconductor field effect transistor detectors (MOSFETs) as in vivo dosimeters to measure rectal dose in high dose rate brachytherapy treatments. The MOSFET arrays were calibrated with an Ir192 source and phantom measurements were performed to check agreement with the treatment planning system. The angular dependence, linearity and constancy of the detectors were evaluated. For in vivo measurements two sites were investigated, transperineal needle implants for prostate cancer and Fletcher suites for cervical cancer. The MOSFETs were inserted into the patients' rectum in theatre inside a modified flatus tube. The patients were then CT scanned for treatment planning. Measured rectal doses during treatment were compared with point dose measurements predicted by the TPS. The MOSFETs were found to require individual calibration factors. The calibration was found to drift by approximately 1% ±0.8 per 500 mV accumulated and varies with distance from source due to energy dependence. In vivo results for prostate patients found only 33% of measured doses agreed with the TPS within ±10%. For cervix cases 42% of measured doses agreed with the TPS within ±10%, however of those not agreeing variations of up to 70% were observed. One of the most limiting factors in this study was found to be the inability to prevent the MOSFET moving internally between the time of CT and treatment. Due to the many uncertainties associated with MOSFETs including calibration drift, angular dependence and the inability to know their exact position at the time of treatment, we consider them to be unsuitable for in vivo dosimetry in rectum for HDR brachytherapy.

  16. Evaluation of linear array MOSFET detectors for in vivo dosimetry to measure rectal dose in DHR brachytherapy

    International Nuclear Information System (INIS)

    Haughey, A.; Coalter, G.; Mugabe, K.

    2011-01-01

    Full text: The study aimed to assess the suitability of linear array metal oxide semiconductor field effect transistor detectors (MOSFETs) as in vivo dosimeters to measure rectal dose in high dose rate brachytherapy treatments. The MOSFET arrays were calibrated with an Ir192 source and phantom measurements were performed to check agreement with the treatment planning system. The angular dependence, linearity and constancy of the detectors were evaluated. For in vivo measurements two sites were investigated, transperineal needle implants for prostate cancer and Fletcher suites for cervical cancer. The MOSFETs were inserted into the patients' rectum in theatre inside a modified flatus tube. The patients were then CT scanned for treatment planning. Measured rectal doses during treatment were compared with point dose measurements predicted by the TPS. The MOSFETs were found to require individual calibration factors. The calibration was found to drift by approximately 1% ±0.8 per 500 mV accumulated and varies with distance from source due to energy dependence. In vivo results for prostate patients found only 33% of measured doses agreed with the TPS within ±1O%. For cervix cases 42% of measured doses agreed with the TPS within ± 10%, however of those not agreeing variations of up to 70% were observed. One of the most limiting factors in this study was found to be the inability to prevent the MOSFET moving internally between the time of CT and treatment. Due to the many uncertainties associated with MOSFETs including calibration drift, angular dependence and the inability to know their exact position at the time of treatment, we consider them to be unsuitable for in vivo dosimetry in rectum for HDR brachytherapy. (author)

  17. Evaluation of peripheral artery stent with 64-slice multi-detector row CT angiography: Prospective comparison with digital subtraction angiography

    International Nuclear Information System (INIS)

    Li Xiaoming; Li Yuhua; Tian Jianming; Xiao Yi; Lu Jianping; Jing Zaiping; Sheng Jing; Edwin, Angela; Wu Fanghong

    2010-01-01

    Purpose: To assess the accuracy of 64-slice multi-detector row computed tomography (MDCT) angiography in the evaluation of peripheral artery in-stent or peristent restenosis, with conventional digital subtraction angiography (DSA) as the reference standard. Materials and methods: Forty-one patients (30 men, 11 women; mean age, 69.8 ± 9.2 years) with symptomatic peripheral arterial occlusive disease after peripheral artery stenting (81 stented lesions) underwent both conventional DSA and 64-slice MDCT angiography. Each stent was classified as evaluable or unevaluable, and every stent was divided into three segments (proximal stent, stent body, and distal stent), resulting in 243 segments. For evaluation, stenosis was graded as follows: 1, none or slight stenosis (<25%); 2, mild stenosis (25-49%); 3, moderate stenosis (50-74%); 4, severe stenosis or total occlusion (≥75%). Two readers evaluated all CT angiograms with regard to narrowing of in-stent or peristent restenosis by consensus. Results were compared with findings of the DSA. Results: Of 81 stents, 62 (76.5%) were determined to be assessable. The metal artifact of the gold marker and motion artifact increased uninterpretability of the images of stents. Overall, 24 of 28 in-stent restenosis and 38 of 53 persistent restenosis were correctly detected by MDCT (85.7% and 71.7% sensitivity). In evaluable stents, 21 of 22 in-stent restenoses and 27 of 28 persistent restenosis were correctly detected (95.4% and 96.4% sensitivity). Additionally, as the grade of stenosis increases, the mean level of CT values in the stent lumina decreases linearly accordingly. Conclusion: 64-Slice MDCT has a high accuracy for the detection of significant in-stent or peristent restenosis of assessable stents in patients with peripheral artery stent implantation and therefore can be considered as a valuable noninvasive technique for stent surveillance.

  18. An evaluation of the process and initial impact of disseminating a nursing e-thesis.

    Science.gov (United States)

    Macduff, Colin

    2009-05-01

    This paper is a report of a study conducted to evaluate product, process and outcome aspects of the dissemination of a nursing PhD thesis via an open-access electronic institutional repository. Despite the growth of university institutional repositories which make theses easily accessible via the world wide web, nursing has been very slow to evaluate related processes and outcomes. Drawing on Stake's evaluation research methods, a case study design was adopted. The case is described using a four-phase structure within which key aspects of process and impact are reflexively analysed. In the conceptualization/re-conceptualization phase, fundamental questions about the purpose, format and imagined readership for a published nursing PhD were considered. In the preparation phase, seven key practical processes were identified that are likely to be relevant to most e-theses. In the dissemination phase email invitations were primarily used to invite engagement. The evaluation phase involved quantitative indicators of initial impact, such as page viewing and download statistics and qualitative feedback on processes and product. Analysis of process and impact elements of e-thesis dissemination is likely to have more than intrinsic value. The advent of e-theses housed in web-based institutional repositories has the potential to transform thesis access and use. It also offers potential to transform the nature and scope of thesis production and dissemination. Nursing scholars can exploit and evaluate such opportunities.

  19. Evaluation of leadership skills during the simulation education course for the initial management of blunt trauma.

    Science.gov (United States)

    Schott, Eric; Brautigam, Robert T; Smola, Jacqueline; Burns, Karyl J

    2012-04-01

    Leadership skills of senior residents, trauma fellows, and a nurse practitioner were assessed during simulation training for the initial management of blunt trauma. This was a pilot, observational study, that in addition to skill development and assessment also sought to determine the need for a dedicated leadership training course for surgical residents. The study evaluated the leadership skills and adherence to Advance Trauma Life Support (ATLS) guidelines of the team leaders during simulation training. The team leaders' performances on criteria regarding prearrival planning, critical actions based on ATLS, injury identification, patient management, and communication were evaluated for each of five blunt-trauma scenarios. Although there was a statistically significant increase in leadership skills for performing ATLS critical actions, P skills for team leadership willbe a worthwhile endeavor at our institution.

  20. Evaluation of a gas chromatograph with a novel surface acoustic wave detector (SAW GC) for screening of volatile organic compounds in Hanford waste tank samples

    International Nuclear Information System (INIS)

    Lockrem, L.L.

    1998-01-01

    A novel instrument, a gas chromatograph with a Surface Acoustic Wave Detector (SAW GC), was evaluated for the screening of organic compounds in Hanford tank headspace vapors. Calibration data were developed for the most common organic compounds, and the accuracy and precision were measured with a certified standard. The instrument was tested with headspace samples collected from seven Hanford waste tanks

  1. Evaluation of COSMO-ART in the Framework of the Air Quality Model Evaluation International Initiative (AQMEII)

    Science.gov (United States)

    Giordano, Lea; Brunner, Dominik; Im, Ulas; Galmarini, Stefano

    2014-05-01

    The Air Quality Model Evaluation International Initiative (AQMEII) coordinated by the EC-JRC and US-EPA, promotes since 2008 research on regional air quality model evaluation across the atmospheric modelling communities of Europe and North America. AQMEII has now reached its Phase 2 that is dedicated to the evaluation of on-line coupled chemistry-meteorology models as opposed to Phase 1 where only off-line models were considered. At European level, AQMEII collaborates with the COST Action "European framework for on-line integrated air quality and meteorology modelling" (EuMetChem). All European groups participating in AQMEII performed simulations over the same spatial domain (Europe at a resolution of about 20 km) and using the same simulation strategy (e.g. no nudging allowed) and the same input data as much as possible. The initial and boundary conditions (IC/BC) were shared between all groups. Emissions were provided by the TNO-MACC database for anthropogenic emissions and the FMI database for biomass burning emissions. Chemical IC/BC data were taken from IFS-MOZART output, and meteorological IC/BC from the ECWMF global model. Evaluation data sets were collected by the Joint Research Center (JRC) and include measurements from surface in situ networks (AirBase and EMEP), vertical profiles from ozone sondes and aircraft (MOZAIC), and remote sensing (AERONET, satellites). Since Phase 2 focuses on on-line coupled models, a special effort is devoted to the detailed speciation of particulate matter components, with the goal of studying feedback processes. For the AQMEII exercise, COSMO-ART has been run with 40 levels of vertical resolution, and a chemical scheme that includes the SCAV module of Knote and Brunner (ACP 2013) for wet-phase chemistry and the SOA treatment according to VBS (volatility basis set) approach (Athanasopoulou et al., ACP 2013). The COSMO-ART evaluation shows that, next to a good performance in the meteorology, the gas phase chemistry is well

  2. Detector Unit

    CERN Multimedia

    1960-01-01

    Original detector unit of the Instituut voor Kernfysisch Onderzoek (IKO) BOL project. This detector unit shows that silicon detectors for nuclear physics particle detection were already developed and in use in the 1960's in Amsterdam. Also the idea of putting 'strips' onto the silicon for high spatial resolution of a particle's impact on the detector were implemented in the BOL project which used 64 of these detector units. The IKO BOL project with its silicon particle detectors was designed, built and operated from 1965 to roughly 1977. Detector Unit of the BOL project: These detectors, notably the ‘checkerboard detector’, were developed during the years 1964-1968 in Amsterdam, The Netherlands, by the Natuurkundig Laboratorium of the N.V. Philips Gloeilampen Fabrieken. This was done in close collaboration with the Instituut voor Kernfysisch Onderzoek (IKO) where the read-out electronics for their use in the BOL Project was developed and produced.

  3. Detector trends

    International Nuclear Information System (INIS)

    Charpak, G.

    1986-01-01

    The author describes briefly the development of detectors for high energy physics experiments. Especially considered are semiconductor microstrip detectors, drift tubes, holographic bubble chambers, scintillating fiber optics, and calorimeters. (HSI).

  4. Participatory Planning, Monitoring and Evaluation of Multi-Stakeholder Platforms in Integrated Landscape Initiatives.

    Science.gov (United States)

    Kusters, Koen; Buck, Louise; de Graaf, Maartje; Minang, Peter; van Oosten, Cora; Zagt, Roderick

    2017-03-21

    Integrated landscape initiatives typically aim to strengthen landscape governance by developing and facilitating multi-stakeholder platforms. These are institutional coordination mechanisms that enable discussions, negotiations, and joint planning between stakeholders from various sectors in a given landscape. Multi-stakeholder platforms tend to involve complex processes with diverse actors, whose objectives and focus may be subjected to periodic re-evaluation, revision or reform. In this article we propose a participatory method to aid planning, monitoring, and evaluation of such platforms, and we report on experiences from piloting the method in Ghana and Indonesia. The method is comprised of three components. The first can be used to look ahead, identifying priorities for future multi-stakeholder collaboration in the landscape. It is based on the identification of four aspirations that are common across multi-stakeholder platforms in integrated landscape initiatives. The second can be used to look inward. It focuses on the processes within an existing multi-stakeholder platform in order to identify areas for possible improvement. The third can be used to look back, identifying the main outcomes of an existing platform and comparing them to the original objectives. The three components can be implemented together or separately. They can be used to inform planning and adaptive management of the platform, as well as to demonstrate performance and inform the design of new interventions.

  5. Development and initial evaluation of Transdiagnostic Behavior Therapy (TBT) for veterans with affective disorders.

    Science.gov (United States)

    Gros, Daniel F

    2014-12-15

    Considerable attention has focused on the growing need for evidence-based psychotherapy for veterans with affective disorders within the Department of Veteran Affairs. Despite, and possibly due to, the large number of evidence-based protocols available, several obstacles remain in their widespread delivery within Veterans Affairs Medical Centers. In part as an effort to address these concerns, newer transdiagnostic approaches to psychotherapy have been developed to provide a single treatment that is capable of addressing several, related disorders. The goal of the present investigation was to develop and evaluate a transdiagnostic psychotherapy, Transdiagnostic Behavior Therapy (TBT), in veterans with affective disorders. Study 1 provided initial support for transdiagnostic presentation of evidence-based psychotherapy components in veterans with principal diagnoses of affective disorders (n=15). These findings were used to inform the development of the TBT protocol. In Study 2, an initial evaluation of TBT was completed in a second sample of veterans with principal diagnoses of affective disorders (n=29). The findings of Study 2 demonstrated significant improvements in symptoms of depression, anxiety, stress, posttraumatic stress, and related impairment across participants with various principal diagnoses. Together, the investigation provided preliminary support for effectiveness of TBT in veterans with affective disorders. Published by Elsevier Ireland Ltd.

  6. Online support and education for dementia caregivers: overview, utilization, and initial program evaluation.

    Science.gov (United States)

    Glueckauf, Robert L; Ketterson, Timothy U; Loomis, Jeffrey S; Dages, Pat

    2004-01-01

    Family caregivers of older adults with progressive dementia (e.g., Alzheimer's disease) are confronted with a variety of challenges in providing assistance to their loved ones, such as dealing with persistent, repetitive questions, managing episodes of agitation and aggressive responding, as well as monitoring hygiene and self-care activities. Although professional and governmental organizations have called for the creation of community-based education and support programs, a significant proportion of dementia caregivers in the United States continue to receive little or no formal instruction in responding effectively to these anxiety-provoking situations. This paper describes the development and implementation of Alzheimer's Caregiver Support Online (also known as AlzOnline), an Internet- and telephone-based education and support network for caregivers of individuals with progressive dementia. An outcome analysis of a Robert Wood Johnson Foundation-funded strategic marketing initiative to promote the use of AlzOnline is reviewed, followed by a presentation of the findings of an initial program evaluation. Finally, future directions for online caregiver evaluation research are proposed.

  7. Experiences from the anatomy track in the ontology alignment evaluation initiative.

    Science.gov (United States)

    Dragisic, Zlatan; Ivanova, Valentina; Li, Huanyu; Lambrix, Patrick

    2017-12-04

    One of the longest running tracks in the Ontology Alignment Evaluation Initiative is the Anatomy track which focuses on aligning two anatomy ontologies. The Anatomy track was started in 2005. In 2005 and 2006 the task in this track was to align the Foundational Model of Anatomy and the OpenGalen Anatomy Model. Since 2007 the ontologies used in the track are the Adult Mouse Anatomy and a part of the NCI Thesaurus. Since 2015 the data in the Anatomy track is also used in the Interactive track of the Ontology Alignment Evaluation Initiative. In this paper we focus on the Anatomy track in the years 2007-2016 and the Anatomy part of the Interactive track in 2015-2016. We describe the data set and the changes it went through during the years as well as the challenges it poses for ontology alignment systems. Further, we give an overview of all systems that participated in the track and the techniques they have used. We discuss the performance results of the systems and summarize the general trends. About 50 systems have participated in the Anatomy track. Many different techniques were used. The most popular matching techniques are string-based strategies and structure-based techniques. Many systems also use auxiliary information. The quality of the alignment has increased for the best performing systems since the beginning of the track and more and more systems check the coherence of the proposed alignment and implement a repair strategy. Further, interacting with an oracle is beneficial.

  8. How to evaluate network initiatives in urban planning - studying area based initiatives (Kvarterløft) in Denmark"

    DEFF Research Database (Denmark)

    Agger, Annika

    This article presents a theoretical and empirical contribution to the discussions of more inclusive and participatory modes of governing that are taking place in many western countries. It develops a critical evaluation framework for assessing the qualities and outcomes of citizens participating ...... planning process in a urban environment in Denmark that focus on improving deprived urban neighbourhoods by mobilising networks....... in collaborative planning processes. This is done by introducing the concepts of institutional capacity and empowerment that derives from different fields of literature, but that covers different perspectives when assessing citizen participation. Some of the central questions raised in the article are: What...

  9. Infrared detectors

    CERN Document Server

    Rogalski, Antonio

    2010-01-01

    This second edition is fully revised and reorganized, with new chapters concerning third generation and quantum dot detectors, THz detectors, cantilever and antenna coupled detectors, and information on radiometry and IR optics materials. Part IV concerning focal plane arrays is significantly expanded. This book, resembling an encyclopedia of IR detectors, is well illustrated and contains many original references … a really comprehensive book.-F. Sizov, Institute of Semiconductor Physics, National Academy of Sciences, Kiev, Ukraine

  10. Systemic characterization and evaluation of particle packings as initial sets for discrete element simulations

    Science.gov (United States)

    Morfa, Carlos Recarey; Cortés, Lucía Argüelles; Farias, Márcio Muniz de; Morales, Irvin Pablo Pérez; Valera, Roberto Roselló; Oñate, Eugenio

    2018-07-01

    A methodology that comprises several characterization properties for particle packings is proposed in this paper. The methodology takes into account factors such as dimension and shape of particles, space occupation, homogeneity, connectivity and isotropy, among others. This classification and integration of several properties allows to carry out a characterization process to systemically evaluate the particle packings in order to guarantee the quality of the initial meshes in discrete element simulations, in both the micro- and the macroscales. Several new properties were created, and improvements in existing ones are presented. Properties from other disciplines were adapted to be used in the evaluation of particle systems. The methodology allows to easily characterize media at the level of the microscale (continuous geometries—steels, rocks microstructures, etc., and discrete geometries) and the macroscale. A global, systemic and integral system for characterizing and evaluating particle sets, based on fuzzy logic, is presented. Such system allows researchers to have a unique evaluation criterion based on the aim of their research. Examples of applications are shown.

  11. Systemic characterization and evaluation of particle packings as initial sets for discrete element simulations

    Science.gov (United States)

    Morfa, Carlos Recarey; Cortés, Lucía Argüelles; Farias, Márcio Muniz de; Morales, Irvin Pablo Pérez; Valera, Roberto Roselló; Oñate, Eugenio

    2017-10-01

    A methodology that comprises several characterization properties for particle packings is proposed in this paper. The methodology takes into account factors such as dimension and shape of particles, space occupation, homogeneity, connectivity and isotropy, among others. This classification and integration of several properties allows to carry out a characterization process to systemically evaluate the particle packings in order to guarantee the quality of the initial meshes in discrete element simulations, in both the micro- and the macroscales. Several new properties were created, and improvements in existing ones are presented. Properties from other disciplines were adapted to be used in the evaluation of particle systems. The methodology allows to easily characterize media at the level of the microscale (continuous geometries—steels, rocks microstructures, etc., and discrete geometries) and the macroscale. A global, systemic and integral system for characterizing and evaluating particle sets, based on fuzzy logic, is presented. Such system allows researchers to have a unique evaluation criterion based on the aim of their research. Examples of applications are shown.

  12. Evaluation of various planar gaseous detectors with CsI photocathodes for the detection of primary scintillation light from noble gases

    CERN Document Server

    Periale, L; Carlson, P J; Francke, T; Iacobaeus, C; Pavlopoulos, P; Pietropaolo, F; Sokolova, T

    2003-01-01

    Noble gases and liquids are excellent scintillators and this opens a unique opportunity to directly detect the primary scintillation light produced in these media by photons or particles. This signal can be used for several purposes, for example as a start signal for TPCs or for particles identification. Usually photomultipliers (PMs) are used for the detection of the scintillation light. In our previous work we have demonstrated that costly PMs could be replaced by gaseous detectors with CsI photocathodes . Such detectors have the same quantum efficiency as the best PMs but at the same time are cheap, simple and have high position and time resolutions. The aim of this work is to evaluate various planar type gaseous detectors with CsI photocahodes in order to choose the best one for the detection of the primary scintillation light from noble gases and liquids.

  13. Initial evaluation of the radioecological situation at the Semipalatinsk Test Site in the Republic of Kazakhstan

    Energy Technology Data Exchange (ETDEWEB)

    Voigt, G.; Semiochkina, N. [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Inst. fuer Strahlenschutz

    1998-12-31

    The Semipalatinsk Test Site (STS) located in the Republic of Kazakhstan (Figure 1.1) was one of the major nuclear weapon test sites of the former Soviet Union. At the site, four hundred fifty six nuclear explosions took place between 1949 and 1989 within the STS (Mikhailov et al. 1996; Dubasov et al. 1994a), resulting in radioactive contamination both within and around the STS. Incidences of radiation related illnesses in such areas may be higher than normal levels (Burkhart 1996). Published estimates of the resulting dose to the public vary according to the source, but an independent study (Grosche 1996) indicated that as many as 30,000-40,000 people could have been exposed to an average dose of 1.6 Sv (160 rem) or more (mainly due to short-lived radionuclides such as {sup 131}I). A detailed international assessment of the impact of these tests on the local population has not yet been undertaken. A current investigation under the acronym, RADTEST, includes an evaluation of Semipalatinsk as part of a broad review of internal and external doses to people arising from nuclear tests at many different sites in the world. In the context of the European Commission funded project RESTORE (Restoration Strategy for Radioactive Contaminated Ecosystems) an attempt is being made to assess the present radiolecological situation in the STS. This initial report collates currently available data published in Russian-language literature and internal CIS reports, reports from Europe and the USA, and other international literature. In this initial evaluation, only an overview of published data made available to the RESTORE project is provided and briefly discussed. In addition, further assessments including experimental work are suggested. Additional sources of data will be pursued and will be integrated with experimental results in the final evaluation report. (orig.)

  14. Initial evaluation of the radioecological situation at the Semipalatinsk Test Site in the Republic of Kazakhstan

    International Nuclear Information System (INIS)

    Voigt, G.; Semiochkina, N.

    1998-01-01

    The Semipalatinsk Test Site (STS) located in the Republic of Kazakhstan (Figure 1.1) was one of the major nuclear weapon test sites of the former Soviet Union. At the site, four hundred fifty six nuclear explosions took place between 1949 and 1989 within the STS (Mikhailov et al. 1996; Dubasov et al. 1994a), resulting in radioactive contamination both within and around the STS. Incidences of radiation related illnesses in such areas may be higher than normal levels (Burkhart 1996). Published estimates of the resulting dose to the public vary according to the source, but an independent study (Grosche 1996) indicated that as many as 30,000-40,000 people could have been exposed to an average dose of 1.6 Sv (160 rem) or more (mainly due to short-lived radionuclides such as 131 I). A detailed international assessment of the impact of these tests on the local population has not yet been undertaken. A current investigation under the acronym, RADTEST, includes an evaluation of Semipalatinsk as part of a broad review of internal and external doses to people arising from nuclear tests at many different sites in the world. In the context of the European Commission funded project RESTORE (Restoration Strategy for Radioactive Contaminated Ecosystems) an attempt is being made to assess the present radiolecological situation in the STS. This initial report collates currently available data published in Russian-language literature and internal CIS reports, reports from Europe and the USA, and other international literature. In this initial evaluation, only an overview of published data made available to the RESTORE project is provided and briefly discussed. In addition, further assessments including experimental work are suggested. Additional sources of data will be pursued and will be integrated with experimental results in the final evaluation report. (orig.)

  15. [Evaluation of Dose Reduction of the Active Collimator in Multi Detector Row CT].

    Science.gov (United States)

    Ueno, Hiroyuki; Matsubara, Kosuke

    The purpose of this study was to evaluate the performance of active collimator by changing acquisition parameters and obtaining dose profiles in z-axis direction. Dose profiles along z-axis were obtained using XRQA2 Gafchromic film. As a result, the active collimator reduced overranging about 55% compared to that without the active collimator. In addition, by changing the combination of X-ray beam width (32 mm, 40 mm), pitch factor (1.4, 0.6), and the X-ray tube rotation time (0.5 s/rot, 1.0 s/rot), the overranging changed from 19.4 to 34.9 mm. Although the active collimator is effective for reducing overranging, it is necessary to adjust acquisition parameters by taking the properties of the active collimator for acquisition parameters, especially setting beam width, into consideration.

  16. Evaluation of in-core measurements with self-powered detectors

    International Nuclear Information System (INIS)

    Spoden, E.

    1977-01-01

    A calculational method is presented for transformation of n-β currents into relative thermal neutron fluxes taking into account an epithermal correction. The difference between epithermal corrections with cross section ratios is demonstrated based on calculations with NR approximation and multiplied by the ratio of mean epithermal and thermal first collision probabilities as well as on calculations using the model of infinite dilution. The effects of this difference on axial power density distribution, relative power of the fuel assemblies, and the inhomogeneity coefficients are discussed in the light of a characteristic measurement with rhodium emitter in a WWER-type reactor. The effect of errors in the nuclear data on the mean error of relative thermal neutron flux is evaluated. (author)

  17. Multi-detector CT evaluation in patients suspected of tracheobronchomalacia: Comparison of end-expiratory with dynamic expiratory volumetric acquisitions

    Energy Technology Data Exchange (ETDEWEB)

    Ferretti, Gilbert R. [Department of Radiology (France)], E-mail: gferretti@chu-grenoble.fr; Jankowski, Adrien [Department of Radiology (France)], E-mail: ajankowski@chu-grenoble.fr; Perrin, Marie Amelie [Department of Radiology (France)], E-mail: maperrin@chu-grenoble.fr; Chouri, Nathalie [Department of Respiratory Diseases (France)], E-mail: nchouri@chu-grenoble.fr; Arnol, Nathalie [Sleep Laboratory and EFCR, University Hospital, Grenoble (France); HP2 Laboratory, INSERM ERI 0017 (Hypoxia: Pathophysiology), Joseph Fourier University, Grenoble (France)], E-mail: narnold@chu-grenoble.fr; Aubaud, Laurent [Department of Radiology (France)], E-mail: laubaud@chu-grenoble.fr; Pepin, Jean-Louis [Sleep Laboratory and EFCR, University Hospital, Grenoble (France); HP2 Laboratory, INSERM ERI 0017 (Hypoxia: Pathophysiology), Joseph Fourier University, Grenoble (France)], E-mail: jlpepin@chu-grenoble.fr

    2008-11-15

    Purpose: The aim of this study was to compare dynamic expiratory imaging and end-expiratory imaging using multi-detector CT (MDCT) of the central airways in patients suspected of tracheobronchomalacia (TBM). Methods: This study had local ethical committee approval. Seventy patients suspected of TBM were prospectively included. All patients underwent evaluation of central airways by three different low-dose MDCT acquisitions: end inspiration, end expiration, and dynamic expiration. Degree of airway collapse was measured by calculating the percentage change in the area and diameter of the airways between inspiratory and the two expiratory techniques at three levels of the trachea and in the sagittal diameter of the right and left main bronchi. Three threshold levels of percentage reduction in diameter or area (30%, 50%, and 70%) for defining TBM were evaluated. Results: In the entire population, the mean percentage of airway collapse was significantly greater with dynamic expiratory imaging than with the end-expiratory imaging at three different levels: lower thoracic trachea (26% vs. 16.6%, p < 0.009), right (25.2% vs. 14%, p < 0.01) and left main (24.7% vs. 13.3%, p < 0.01) bronchus. Whatever the threshold value for defining TBM, dynamic expiratory imaging always resulted in diagnosing TBM in more patients than end-expiratory imaging. Conclusions: Dynamic expiratory imaging shows a significantly greater degree and a significantly greater extent of airway collapse than standard end-expiratory imaging in patients suspected of TBM. Further evaluation of the clinical relevance of such findings is warranted.

  18. Chinese Military Evaluation of a Portable Near-Infrared Detector of Traumatic Intracranial Hematomas.

    Science.gov (United States)

    Liang, Chun-Yang; Yang, Yang; Shen, Chun-Sen; Wang, Hai-Jiang; Liu, Nai-Ming; Wang, Zhi-Wen; Zhu, Feng-Lei; Xu, Ru-Xiang

    2018-02-06

    Secondary brain injury is the main cause of mortality from traumatic brain injury (TBI). One hallmark of TBI is intracranial hemorrhage, which occurs in 40-50% of severe TBI cases. Early identification of intracranial hematomas in TBI patients allows early surgical evacuation and can reduce the case fatality rate of TBI. As pre-hospital care is the weakest part of Chinese emergency care, there is an urgent need for a capability to detect brain hematomas early. In China, in addition to preventing injuries and diseases in military staff and in enhancing the military armed forces during war, military medicine participates in actions such as emergency public health crises, natural disasters, emerging conflicts, and anti-terrorist campaigns during peacetime. The purpose of this observational study is to evaluate in the Chinese military general hospital the performance of a near-infrared (NIR)-based portable device, developed for US Military, in the detection of traumatic intracranial hematomas. The endpoint of the study was a description of the test characteristics (sensitivity, specificity, and positive and negative predictive values [NPV]) of the portable NIR-based device in identification of hematomas within its detection limits (volume >3.5 mL and depth hematoma detection in patients sustaining TBI. Data were collected in the People's Liberation Army General Hospital in Beijing using the NIR device at the time of CT scans, which were performed to evaluate suspected TBI. One hundred and twenty seven patients were screened, and 102 patients were included in the per protocol population. Of the 102 patients, 24 were determined by CT scan to have intracranial hemorrhage. The CT scans were read by an independent neuroradiologist who was blinded to the NIR measurements. The NIR device demonstrated sensitivity of 100% (95% confidence intervals [CI] 82.8-100%) and specificity of 93.6% (95%CI 85-97.6%) in detecting intracranial hematomas larger than 3.5 mL in volume and that

  19. Evaluation of dose distributions in gamma chamber using glass plate detector

    Directory of Open Access Journals (Sweden)

    Narayan Pradeep

    2008-01-01

    Full Text Available A commercial glass plate of thickness 1.75 mm has been utilized for evaluation of dose distributions inside the irradiation volume of gamma chamber using optical densitometry technique. The glass plate showed linear response in the dose range 0.10 Kilo Gray (kGy to 10 kGy of cobalt-60 gamma radiation with optical sensitivity 0.04 Optical Density (OD /kGy. The change in the optical density at each identified spatial dose matrix on the glass plate in relation to the position in the irradiation volume has been presented as dose distributions inside the gamma chamber. The optical density changes have been graphically plotted in the form of surface diagram of color washes for different percentage dose rate levels as isodose distributions in gamma chamber. The variation in dose distribution inside the gamma chamber unit, GC 900, BRIT India make, using this technique has been observed within ± 15%. This technique can be used for routine quality assurances and dose distribution validation of any gamma chamber during commissioning and source replacement. The application of commercial glass plate for dose mapping in gamma chambers has been found very promising due to its wider dose linearity, quick measurement, and lesser expertise requirement in application of the technique.

  20. Evaluation of detector responses to natural environmental and fall-out gamma radiation

    International Nuclear Information System (INIS)

    Arvela, H.

    1988-01-01

    Instrument responses to the thorium, uranium and potassium components of the natural environmental as well as the fall-out radiation field were evaluated. The responses to the 137 Cs fall-out radiation field differ by less than 6% from the response at 0.662 MeV, except for that of the NaI scintillator. Differences of more than 30% were found in the responses of two energy compensated instruments to normal natural background radiation and to radiation from fresh fall-out. The best estimate of the terrestrial component of the dose rate measured was obtained by carrying out the following corrections of the measured readings: cosmic ray contribution and internal background subtraction with response correction, including 137 Cs calibration correction. After the Chernobyl accident the dose rate levels due to 137 Cs and 134 Cs fall-out were comparable to the natural background gamma radiation. The responses calculated as well as the results from measurements of the low level environmental exposure levels caused by the Chernobyl fall-out, confirmed the need to take into account the instrument response to natural as well as fall-out radiation fields. (author)

  1. Chronic thromboembolic pulmonary hypertension: Evaluation with 64-detector row CT versus digital substraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Reichelt, Angela [Department of Diagnostic Radiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover (Germany)], E-mail: Reichelt.Angela@mh-hannover.de; Hoeper, Marius M. [Department of Respiratory Medicine, Hannover Medical School (Germany); Galanski, Michael [Department of Diagnostic Radiology, Hannover Medical School, Carl Neuberg Str. 1, 30625 Hannover (Germany); Keberle, Marc [Department of Diagnostic Radiology and Nuclear Medicine, Bruederkrankenhaus St. Josef Paderborn (Germany)

    2009-07-15

    The aim of the study was to evaluate the role of 64-row CT in the diagnostic workup of patients with chronic thromboembolic pulmonary hypertension (CTEPH) using digital substraction angiography (DSA) as the method of diagnostic reference. CT and DSA studies of 27 patients (54 main, 162 lobar and 540 segmental arteries) with a clinical suspicion of CTEPH were included in this retrospective and blinded analysis. Axial images and multiplanar thin maximum intensity projections (MIPs) (3 mm) were consequently used for exact image interpretation whereas additional reconstructed thick MIPs gave an overview of the entire vascular tree comparable to DSA. Sensitivity and specificity of CT regarding CTEPH-related pathological changes in general were 98.3% and 94.8% at main/lobar level and 94.1% and 92.9% at segmental level, respectively. Sensitivity and specificity of CT regarding the different pathological criteria of CTEPH (complete obstruction, intimal irregularities, bands and webs, indirect signs) were 88.9-100% and 96.1-100% at main/lobar level and 84.3-90.5% and 92-98.7% at segmental level, respectively. Our results show that CT is an accurate and reliable non-invasive alternative to conventional DSA in the diagnostic workup in patients with CTEPH.

  2. Chronic thromboembolic pulmonary hypertension: Evaluation with 64-detector row CT versus digital substraction angiography

    International Nuclear Information System (INIS)

    Reichelt, Angela; Hoeper, Marius M.; Galanski, Michael; Keberle, Marc

    2009-01-01

    The aim of the study was to evaluate the role of 64-row CT in the diagnostic workup of patients with chronic thromboembolic pulmonary hypertension (CTEPH) using digital substraction angiography (DSA) as the method of diagnostic reference. CT and DSA studies of 27 patients (54 main, 162 lobar and 540 segmental arteries) with a clinical suspicion of CTEPH were included in this retrospective and blinded analysis. Axial images and multiplanar thin maximum intensity projections (MIPs) (3 mm) were consequently used for exact image interpretation whereas additional reconstructed thick MIPs gave an overview of the entire vascular tree comparable to DSA. Sensitivity and specificity of CT regarding CTEPH-related pathological changes in general were 98.3% and 94.8% at main/lobar level and 94.1% and 92.9% at segmental level, respectively. Sensitivity and specificity of CT regarding the different pathological criteria of CTEPH (complete obstruction, intimal irregularities, bands and webs, indirect signs) were 88.9-100% and 96.1-100% at main/lobar level and 84.3-90.5% and 92-98.7% at segmental level, respectively. Our results show that CT is an accurate and reliable non-invasive alternative to conventional DSA in the diagnostic workup in patients with CTEPH.

  3. The Veteran-Initiated Electronic Care Coordination: A Multisite Initiative to Promote and Evaluate Consumer-Mediated Health Information Exchange.

    Science.gov (United States)

    Klein, Dawn M; Pham, Kassi; Samy, Leila; Bluth, Adam; Nazi, Kim M; Witry, Matthew; Klutts, J Stacey; Grant, Kathleen M; Gundlapalli, Adi V; Kochersberger, Gary; Pfeiffer, Laurie; Romero, Sergio; Vetter, Brian; Turvey, Carolyn L

    2017-04-01

    Information continuity is critical to person-centered care when patients receive care from multiple healthcare systems. Patients can access their electronic health record data through patient portals to facilitate information exchange. This pilot was developed to improve care continuity for rural Veterans by (1) promoting the use of the Department of Veterans Affairs (VA) patient portal to share health information with non-VA providers, and (2) evaluating the impact of health information sharing at a community appointment. Veterans from nine VA healthcare systems were trained to access and share their VA Continuity of Care Document (CCD) with their non-VA providers. Patients and non-VA providers completed surveys on their experiences. Participants (n = 620) were primarily older, white, and Vietnam era Veterans. After training, 78% reported the CCD would help them be more involved in their healthcare and 86% planned to share it regularly with non-VA providers. Veterans (n = 256) then attended 277 community appointments. Provider responses from these appointments (n = 133) indicated they were confident in the accuracy of the information (97%) and wanted to continue to receive the CCD (96%). Ninety percent of providers reported the CCD improved their ability to have an accurate medication list and helped them make medication treatment decisions. Fifty percent reported they did not order a laboratory test or another procedure because of information available in the CCD. This pilot demonstrates feasibility and value of patient access to a CCD to facilitate information sharing between VA and non-VA providers. Outreach and targeted education are needed to promote consumer-mediated health information exchange.

  4. Evaluation of the photon transmission efficiency of light guides used in scintillation detectors using LightTools code

    International Nuclear Information System (INIS)

    Park, Hye Min; Joo, Koan Sik; Kim, Jeong Ho; Kim, Dong Sung; Park, Ki Hyun; Park, Chan Jong; Han, Woo Jin

    2016-01-01

    To optimize the photon transmission efficiency of light guides used in scintillation detectors, LightTools code, which can construct and track light, was used to analyze photon transmission effectiveness with respect to light guides thickness. This analysis was carried out using the commercial light guide, N-BK 7 Optical Glass by SCHOTT, as a model for this study. The luminous exitance characteristic of the LYSO scintillator was used to analyze the photon transmission effectiveness according to the thickness of the light guide. The results of the simulations showed the effectiveness of the photon transmission according to the thickness of the light guide, which was found to be distributed from 13.38% to 33.57%. In addition, the photon transmission efficiency was found to be the highest for light guides of 4 mm of thickness and a receiving angle of 49 .deg. . Through such simulations, it is confirmed that photon transmission efficiency depends on light guide thickness and subsequent changes in the internal angle of reflection. The aim is to produce an actual light guide based on these results and to evaluate its performance

  5. Evaluation of radiation tolerance of FETs used for Astro-E2 hard X-ray detector (HXD-II)

    International Nuclear Information System (INIS)

    Itoh, Takeshi; Niko, Hisako; Kokubun, Motohide; Makishima, Kazuo; Kawaharada, Madoka; Takahashi, Isao; Miyasaka, Hiromasa

    2005-01-01

    We evaluated the radiation tolerance of three types of metal-can MOS Field Effect Transistors (FETs). They are candidates for flight electronics of the Hard X-ray Detector (HXD-II) experiment which is onboard the cosmic X-ray satellite Astro-E2 scheduled for launch in 2005. We irradiated FETs with a Co60γ-ray source under several different experimental conditions, and measured changes in their I-V characteristic curves. After a 10krad irradiation during which the gate voltage is set at 0V, all types showed a decrease in the switching voltage by ∼0.2-0.4V. In addition, the gate conductance increased under some irradiation conditions. These experimental results may be explained in terms of trapped charges and boundary levels in the oxide layer beneath the gate electrode. We have confirmed that at least two types of FETs can be used in our satellite-borne experiment, one as relay-driving FETs and the other in TTL-ECL conversion circuits

  6. Impact of multi-detector row computed tomography on the tactics of cardiovascular surgery. From qualitative evaluation to quantitative assessment

    International Nuclear Information System (INIS)

    Imagawa, Hiroshi; Kawachi, Kanji; Takano, Shinji

    2005-01-01

    We assessed the role of multi-detector row computed tomography in cardiovascular surgery. The efficacy of multi-detector row computed tomography was assessed concerning the graft patency of coronary artery bypass, arterial atheromatous degeneration, small vessel imaging, and left ventricular volume measurement. Images were reconstructed using both the volume-rendering and the maximum-intensity-profile methods. Arterial atherosclerotic degeneration was assessed by aortic wall volume and aortic calcification volume. In the assessment of bypass graft patency, multidetector row computed tomography showed a 98% correct positive ratio with sensitivity and specificity of 98% and 100%, respectively. Atheromatous degeneration showed matching results in more than 70% of cases compared with intraoperative findings. More than 92% of arterial branches with diameters of 3 mm or greater were detected by preoperative multi-detector row computed tomography images, though only 6% of branches with diameters of 2 mm or less could be visualized. There was a positive linear correlation between left ventricular volumes determined by multi-detector row computed tomography and those calculated from cine angiography. Multi-detector row computed tomography clearly visualized coronary bypass grafts and aortic arterial branches, providing detailed vascular images. Atheromatous degeneration assessed by multi-detector row computed tomography was equivalent with intraoperative findings in more than 70% of cases. Left ventricular volumes measured by multi-detector row computed tomography correlated closely with those determined by cine-angiography. Multidetector row computed tomography is an efficient and promising modality in cardiovascular surgery. (author)

  7. In vitro evaluation of 56 coronary artery stents by 256-slice multi-detector coronary CT

    International Nuclear Information System (INIS)

    Steen, Henning; Andre, Florian; Korosoglou, Grigorios; Mueller, Dirk; Hosch, Waldemar; Kauczor, Hans-Ulrich; Giannitsis, Evangelos; Katus, Hugo A.

    2011-01-01

    Objective: We sought to investigate stent lumen visibility of 56 coronary stents with the newest 256-multi-slice-CT (256-MDCT) technology for different reconstruction algorithms in an in vitro model. Background: Early identification of in-stent restenosis (ISR) is important to avoid recurrent ischemia and prevent acute myocardial infarction (AMI). Since angiography has the disadvantage of high costs and its invasiveness, MDCT could be a convenient and safe non-invasive alternative for detection of ISR. Material and methods: Percentages of in-stent lumen diameter and in-stent signal attenuation (measured as contrast-to-noise ratio (CNR)) of 56 coronary stents (group A ≤2.5 mm; group B = 2.75-3.0 mm; group C = 3.5-4.0 mm) were evaluated in a coronary vessel in vitro phantom (iodine-filled plastic tubes) employing four different reconstruction algorithms (XCD, CC, CD, XCB) on a novel 256-MDCT (Philips-iCT, collimation = 128 mm x 0.625 mm; rotation time = 270 ms; tube current = 800 mA s with 120 kV). Analysis was conducted with the semi-automatical full-width-at-half-maximum (FWHM) method. P-values 60% for group C stents was significantly larger and CNR was significantly lower (both p 3.0 mm when analysed with cardio-dedicated sharp kernels, although clinical studies corroborating this claim should be performed. However, stents ≤3.0 mm reconstructed by soft kernels revealed insufficient in-stent lumen visualisation and should not be used in clinical practice. Further improvements in spatial and temporal image resolution as well as reductions of radiation exposure and image noise have to be accomplished for the ambitious goal of characterising both CT coronary artery anatomy and in-stent lumen.

  8. A Geant4 evaluation of the Hornyak button and two candidate detectors for the TREAT hodoscope

    Science.gov (United States)

    Fu, Wenkai; Ghosh, Priyarshini; Harrison, Mark J.; McGregor, Douglas S.; Roberts, Jeremy A.

    2018-05-01

    The performance of traditional Hornyak buttons and two proposed variants for fast-neutron hodoscope applications was evaluated using Geant4. The Hornyak button is a ZnS(Ag)-based device previously deployed at the Idaho National Laboratory's TRansient REActor Test Facility (better known as TREAT) for monitoring fast neutrons emitted during pulsing of fissile fuel samples. Past use of these devices relied on pulse-shape discrimination to reduce the significant levels of background Cherenkov radiation. Proposed are two simple designs that reduce the overall light guide mass (here, polymethyl methacrylate or PMMA), employ silicon photomultipliers (SiPMs), and can be operated using pulse-height discrimination alone to eliminate background noise to acceptable levels. Geant4 was first used to model a traditional Hornyak button, and for assumed, hodoscope-like conditions, an intrinsic efficiency of 0.35% for mono-directional fission neutrons was predicted. The predicted efficiency is in reasonably good agreement with experimental data from the literature and, hence, served to validate the physics models and approximations employed. Geant4 models were then developed to optimize the materials and geometries of two alternatives to the Hornyak button, one based on a homogeneous mixture of ZnS(Ag) and PMMA, and one based on alternating layers of ZnS(Ag) and PMMA oriented perpendicular to the incident neutron beam. For the same radiation environment, optimized, 5-cm long (along the beam path) devices of the homogeneous and layered designs were predicted to have efficiencies of approximately 1.3% and 3.3%, respectively. For longer devices, i.e., lengths larger than 25 cm, these efficiencies were shown to peak at approximately 2.2% and 5.9%, respectively. Moreover, both designs were shown to discriminate Cherenkov noise intrinsically by using an appropriate pulse-height discriminator level, i.e., pulse-shape discrimination is not needed for these devices.

  9. Accuracy evaluation of initialization-free registration for intraoperative 3D-navigation

    International Nuclear Information System (INIS)

    Diakov, Georgi; Freysinger, Wolfgang

    2007-01-01

    Purpose An initialization-free approach for perioperative registration in functional endoscopic sinus surgery (FESS) is sought. The quality of surgical navigation relies on registration accuracy of preoperative images to the patient. Although landmark-based registration is fast, it is prone to human operator errors. This study evaluates the accuracy of two well-known methods for segmentation of the occipital bone from CT-images for use in surgical 3D-navigation. Method The occipital bone was segmented for registration without pre-defined correspondences, with the iterative closest point algorithm (ICP). The thresholding plus marching cubes segmentation (TMCS), and the deformable model segmentation (DMS) were compared quantitatively by overlaying the areas of the segmentations in cross-sectional slices, and visually by displaying the pointwise distances between the segmentations in a three-dimensional distance map relative to an expert manual segmentation, taken as a ''ground truth''. Results Excellent correspondence between the two methods was achieved; the results showed, however, that the TMCS is closer to the ''ground truth''. This is due to the sub-voxel accuracy of the marching cubes algorithm by definition, and the sensitivity of the DMS method to the choice of parameters. The DMS approach, as a gradient-based method, is insensitive to the thresholding initialization. For noisy images and soft tissue delineation a gradient-based method, like the deformable model, performs better. Both methods correspond within minute differences less than 4%. Conclusion These results will allow further minimization of human interaction in the planning phase for intraoperative 3D-navigation, by allowing to automatically create surface patches for registration purposes, ultimately allowing to build an initialization-free, fully automatic registration procedure for navigated Ear-, Nose-, Throat- (ENT) surgery. (orig.)

  10. Description and evaluation of an initiative to develop advanced practice nurses in mainland China.

    Science.gov (United States)

    Wong, Frances Kam Yuet; Peng, Gangyi; Kan, Eva C; Li, Yajie; Lau, Ada T; Zhang, Liying; Leung, Annie F; Liu, Xueqin; Leung, Vilna O; Chen, Weiju; Li, Ming

    2010-05-01

    This paper describes an initiative to develop Advanced Practice Nurses (APNs) in mainland China and evaluation of the outcomes of the described programme. The pioneer project was an APN postgraduate programme involving 38 students conducted in Guangzhou, China during 2004-2005. Data related to curriculum content and process, student performance, self-reported competence and programme effects were collected. Quantitative data such as demographic data, student performance were analysed using descriptive statistics and the pre and post self-reported practice of competence was compared using chi-square test. Qualitative data such as case reports and interviews were examined using thematic analyses. Reflective journals and case studies revealed the attributes of APNs in managing clinical cases at advanced level, applying theory into practice and exercising evidence-based practice. The relatively modest self-reported practice of competence suggested that the graduates were novice APNs and needed continued development after the completion of the programme. This study reports the experience of an initiative in China and suggests a useful curriculum framework for educating APNs. Copyright 2009 Elsevier Ltd. All rights reserved.

  11. Hesitant Trapezoidal Fuzzy QUALIFLEX Method and Its Application in the Evaluation of Green Supply Chain Initiatives

    Directory of Open Access Journals (Sweden)

    Xiaolu Zhang

    2016-09-01

    Full Text Available This paper explores how to handle multiple criteria decision-making (MCDM problems in which the criteria values of alternatives take the form of comparative linguistic expressions. Firstly, the new concept of hesitant trapezoidal fuzzy numbers (HTrFNs is provided to model the semantics of the comparative linguistic expressions. Then, the operational laws and the distance measures of HTrFNs are presented. Afterwards, a useful outranking method, the hesitant trapezoidal fuzzy QUALIFLEX method, is developed to handle the MCDM problems with hierarchical structure in the environment of HTrFN. At length, the proposed method is applied to evaluating green supply chain initiatives in order to achieve sustainable economic and environmental performance, and a case study concerned with a fashion retail chain is presented to demonstrate its feasibility and applicability, also, a comparative analysis with other relevant approaches is conducted to validate the effectiveness of the proposed method.

  12. Evaluation of abdominal CT in the initial treatment of abdominal trauma

    International Nuclear Information System (INIS)

    Watanabe, Shinsuke; Ishii, Takashi; Kuwata, Katsuya; Yoneyama, Chihiro; Kitamura, Kazuya; Sasaki, Yoshifumi; Kamachi, Masahiro; Nishiguchi, Hiroyasu.

    1986-01-01

    During the last four years 102 patients with abdominal trauma were examined by CT for preoperative evaluation in our hospital. In 35 patients (34 %), the CT scans revealed no abnormal findings. They were all managed conservatively except for one case of perforated small bowel. In 67 patients (66 %) CT revealed evidences of substantial abdominal or retroperitoneal trauma. In 30 of them CT findings were confirmed by surgery. Hepatic injury is usually easily recognized by CT. CT is also useful for the detection of renal or splenic injuries. The majority of those parenchymatous organ injuries were successfully managed with conservative therapy, despite apparent traumatic lesions revealed by CT. Repeat CT scans is proved to be very useful to follow the changes of these traumatic lesions. In conclusion, application of abdominal CT is extremely useful for the initial decision making in treatment of patients with abdominal trauma and for the follow-up observation of injured lesions. (author)

  13. Evaluation of a portable gas chromatograph with photoionization detector under variations of VOC concentration, temperature, and relative humidity.

    Science.gov (United States)

    Soo, Jhy-Charm; Lee, Eun Gyung; LeBouf, Ryan F; Kashon, Michael L; Chisholm, William; Harper, Martin

    2018-04-01

    The objective of this present study was to evaluate the performance of a portable gas chromatograph-photoionization detector (GC-PID), under various test conditions to determine if it could be used in occupational settings. A mixture of 7 volatile organic compounds (VOCs)-acetone, ethylbenzene, methyl isobutyl ketone, toluene, m-xylene, p-xylene, and o-xylene-was selected because its components are commonly present in paint manufacturing industries. A full-factorial combination of 4 concentration levels (exposure scenarios) of VOC mixtures, 3 different temperatures (25°C, 30°C, and 35°C), and 3 relative humidities (RHs; 25%, 50%, and 75%) was conducted in a full-size controlled environmental chamber. Three repetitions were conducted for each test condition allowing for estimation of accuracy. Time-weighted average exposure data were collected using solid sorbent tubes (Anasorb 747, SKC Inc.) as the reference sampling medium. Calibration curves of Frog-4000 using the dry gases showed R 2 > 0.99 for all analytes except for toluene (R 2 = 0.97). Frog-4000 estimates within a test condition showed good consistency for the performance of repeated measurement. However, there was ∼41-64% reduction in the analysis of polar acetone with 75% RH relative to collection at 25% RH. Although Frog-4000 results correlated well with solid sorbent tubes (r = 0.808-0.993, except for toluene) most of the combinations regardless of analyte did not meet the <25% accuracy criterion recommended by NIOSH. The effect of chromatographic co-elution can be seen with m, p-xylene when the results are compared to the sorbent tube sampling technique with GC-flame ionization detector. The results indicated an effect of humidity on the quantification of the polar compounds that might be attributed to the pre-concentrator placed in the selected GC-PID. Further investigation may resolve the humidity effect on sorbent trap with micro GC pre-concentrator when water vapor is present. Although this

  14. The International Decision Support Initiative Reference Case for Economic Evaluation: An Aid to Thought.

    Science.gov (United States)

    Wilkinson, Thomas; Sculpher, Mark J; Claxton, Karl; Revill, Paul; Briggs, Andrew; Cairns, John A; Teerawattananon, Yot; Asfaw, Elias; Lopert, Ruth; Culyer, Anthony J; Walker, Damian G

    2016-12-01

    Policymakers in high-, low-, and middle-income countries alike face challenging choices about resource allocation in health. Economic evaluation can be useful in providing decision makers with the best evidence of the anticipated benefits of new investments, as well as their expected opportunity costs-the benefits forgone of the options not chosen. To guide the decisions of health systems effectively, it is important that the methods of economic evaluation are founded on clear principles, are applied systematically, and are appropriate to the decision problems they seek to inform. The Bill and Melinda Gates Foundation, a major funder of economic evaluations of health technologies in low- and middle-income countries (LMICs), commissioned a "reference case" through the International Decision Support Initiative (iDSI) to guide future evaluations, and improve both the consistency and usefulness to decision makers. The iDSI Reference Case draws on previous insights from the World Health Organization, the US Panel on Cost-Effectiveness in Health Care, and the UK National Institute for Health and Care Excellence. Comprising 11 key principles, each accompanied by methodological specifications and reporting standards, the iDSI Reference Case also serves as a means of identifying priorities for methods research, and can be used as a framework for capacity building and technical assistance in LMICs. The iDSI Reference Case is an aid to thought, not a substitute for it, and should not be followed slavishly without regard to context, culture, or history. This article presents the iDSI Reference Case and discusses the rationale, approach, components, and application in LMICs. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  15. Multi-detector CT (MDCT in bowel and mesenteric injury

    Directory of Open Access Journals (Sweden)

    Vajjalla Ravikumar

    2013-04-01

    Full Text Available Objectives: To evaluate multi-detector CT (MDCT findings in bowel and mesenteric injury due to blunt abdominal trauma.Method: Retrospective evaluation of MDCT scan reports of patients admitted in Hamad Medical Corporation, Doha, Qatar with bowel and mesenteric injury during the period of January 2005 to April 2008.Results: MDCT, without using oral contrast, clearly demonstrated various specific and less specific findings of bowel and mesenteric injury.Conclusion: Multi-detector CT is an excellent diagnostic modality in bowel and mesenteric injury. Routine administration of oral contrast agent is not mandatory for initial evaluation of these patients.

  16. Evaluation of dual-phase multi-detector-row CT for detection of intestinal bleeding using an experimental bowel model

    International Nuclear Information System (INIS)

    Dobritz, Martin; Engels, Heinz-Peter; Wieder, Hinrich; Rummeny, Ernst J.; Stollfuss, Jens C.; Schneider, Armin; Feussner, Hubertus

    2009-01-01

    To evaluate dual-phase multi-detector-row computed tomography (MDCT) in the detection of intestinal bleeding using an experimental bowel model and varying bleeding velocities. The model consisted of a high pressure injector tube with a single perforation (1 mm) placed in 10-m-long small bowel of a pig. The bowel was filled with water/contrast solution of 30-40 HU and was incorporated in a phantom model containing vegetable oil to simulate mesenteric fat. Intestinal bleeding in different locations and bleeding velocities varying from zero to 1 ml/min (0.05 ml/min increments, constant bleeding duration of 20 s) was simulated. Nineteen complete datasets in arterial and portal-venous phase using increasing bleeding velocities, and seven negative controls were measured using a 64 MDCT (3-mm slice thickness, 1.5-mm reconstruction increment). Three radiologists blinded to the experimental settings evaluated the datasets in a random order. The likelihood for intestinal bleeding was assessed using a 5-point scale with subsequent ROC analysis. The sensitivity to detect bleeding was 0.44 for a bleeding velocity of 0.10-0.50 ml/min and 0.97 for 0.55-1.00 ml/min. The specificity was 1.00. The area under the curve was calculated to be 0.73, 0.88 and 0.89 for reader 1, 2 and 3, respectively. Dual-phase MDCT provides high sensitivity and specificity in the detection of intestinal bleeding with bleeding velocities of 0.5-1.0 ml/min. Therefore, MDCT should be considered as a primary diagnostic technique in the management of patients with suspected intestinal bleeding. (orig.)

  17. Evaluation of the effective dose and image quality of low-dose multi-detector CT for orthodontic treatment planning

    International Nuclear Information System (INIS)

    Chung, Gi Chung; Han, Won Jeong; Kim, Eun Kyung

    2010-01-01

    This study was designed to compare the effective doses from low-dose and standard-dose multi-detector CT (MDCT) scanning protocols and evaluate the image quality and the spatial resolution of the low-dose MDCT protocols for clinical use. 6-channel MDCT scanner (Siemens Medical System, Forschheim, Germany), was used for this study. Protocol of the standard-dose MDCT for the orthodontic analysis was 130 kV, 35 mAs, 1.25 mm slice width, 0.8 pitch. Those of the low-dose MDCT for orthodontic analysis and orthodontic surgery were 110 kV, 30 mAs, 1.25 mm slice width, 0.85 pitch and 110 kV, 45 mAs, 2.5 mm slice width, 0.85 pitch. Thermoluminescent dosimeters (TLDs) were placed at 31 sites throughout the levels of adult female ART head and neck phantom. Effective doses were calculated according to ICRP 1990 and 2007 recommendations. A formalin-fixed cadaver and AAPM CT performance phantom were scanned for the evaluation of subjective image quality and spatial resolution. Effective doses in μSv (E2007) were 699.1, 429.4 and 603.1 for standard-dose CT of orthodontic treatment, low-dose CT of orthodontic analysis, and low-dose CT of orthodontic surgery, respectively. The image quality from the low-dose protocol were not worse than those from the standard-dose protocol. The spatial resolutions of both standard-dose and low-dose CT images were acceptable. From the above results, it can be concluded that the low-dose MDCT protocol is preferable in obtaining CT images for orthodontic analysis and orthodontic surgery.

  18. Evaluation of the effective dose and image quality of low-dose multi-detector CT for orthodontic treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Gi Chung; Han, Won Jeong; Kim, Eun Kyung [Department of Oral and Maxillofacial Radiology, School of Dentistry, Dankook University, Cheonan (Korea, Republic of)

    2010-03-15

    This study was designed to compare the effective doses from low-dose and standard-dose multi-detector CT (MDCT) scanning protocols and evaluate the image quality and the spatial resolution of the low-dose MDCT protocols for clinical use. 6-channel MDCT scanner (Siemens Medical System, Forschheim, Germany), was used for this study. Protocol of the standard-dose MDCT for the orthodontic analysis was 130 kV, 35 mAs, 1.25 mm slice width, 0.8 pitch. Those of the low-dose MDCT for orthodontic analysis and orthodontic surgery were 110 kV, 30 mAs, 1.25 mm slice width, 0.85 pitch and 110 kV, 45 mAs, 2.5 mm slice width, 0.85 pitch. Thermoluminescent dosimeters (TLDs) were placed at 31 sites throughout the levels of adult female ART head and neck phantom. Effective doses were calculated according to ICRP 1990 and 2007 recommendations. A formalin-fixed cadaver and AAPM CT performance phantom were scanned for the evaluation of subjective image quality and spatial resolution. Effective doses in {mu}Sv (E2007) were 699.1, 429.4 and 603.1 for standard-dose CT of orthodontic treatment, low-dose CT of orthodontic analysis, and low-dose CT of orthodontic surgery, respectively. The image quality from the low-dose protocol were not worse than those from the standard-dose protocol. The spatial resolutions of both standard-dose and low-dose CT images were acceptable. From the above results, it can be concluded that the low-dose MDCT protocol is preferable in obtaining CT images for orthodontic analysis and orthodontic surgery.

  19. EVALUATING THE SENSITIVITY OF RADIONUCLIDE DETECTORS FOR CONDUCTING A MARITIME ON-BOARD SEARCH USING MONTE CARLO SIMULATION IMPLEMENTED IN AVERT(regsign)

    International Nuclear Information System (INIS)

    Harris, S.; Dave Dunn, D.

    2009-01-01

    The sensitivity of two specific types of radionuclide detectors for conducting an on-board search in the maritime environment was evaluated using Monte Carlo simulation implemented in AVERT(reg s ign). AVERT(reg s ign), short for the Automated Vulnerability Evaluation for Risk of Terrorism, is personal computer based vulnerability assessment software developed by the ARES Corporation. The sensitivity of two specific types of radionuclide detectors for conducting an on-board search in the maritime environment was evaluated using Monte Carlo simulation. The detectors, a RadPack and also a Personal Radiation Detector (PRD), were chosen from the class of Human Portable Radiation Detection Systems (HPRDS). Human Portable Radiation Detection Systems (HPRDS) serve multiple purposes. In the maritime environment, there is a need to detect, localize, characterize, and identify radiological/nuclear (RN) material or weapons. The RadPack is a commercially available broad-area search device used for gamma and also for neutron detection. The PRD is chiefly used as a personal radiation protection device. It is also used to detect contraband radionuclides and to localize radionuclide sources. Neither device has the capacity to characterize or identify radionuclides. The principal aim of this study was to investigate the sensitivity of both the RadPack and the PRD while being used under controlled conditions in a simulated maritime environment for detecting hidden RN contraband. The detection distance varies by the source strength and the shielding present. The characterization parameters of the source are not indicated in this report so the results summarized are relative. The Monte Carlo simulation results indicate the probability of detection of the RN source at certain distances from the detector which is a function of transverse speed and instrument sensitivity for the specified RN source

  20. Initial experience in hybrid PET-MRI for evaluation of refractory focal onset epilepsy.

    Science.gov (United States)

    Shin, Hae W; Jewells, Valerie; Sheikh, Arif; Zhang, Jingwen; Zhu, Hongtu; An, Hongyu; Gao, Wei; Shen, Dinggang; Hadar, Eldad; Lin, Weili

    2015-09-01

    We aim to evaluate the utility/improved accuracy of hybrid PET/MR compared to current practice separate 3T MRI and PET-CT imaging for localization of seizure foci. In a pilot study, twenty-nine patients undergoing epilepsy surgery evaluation were imaged using PET/MR. This subject group had 29 previous clinical 3T MRI as well as 12 PET-CT studies. Prior clinical PET and MR images were read sequentially while the hybrid PET/MR was concurrently read. The median interval between hybrid PET/MR and prior imaging studies was 5 months (range 1-77 months). In 24 patients, there was no change in the read between the clinical exams and hybrid PET/MR while new anatomical or functional lesions were identified by hybrid PET/MR in 5 patients without significant clinical change. Four new anatomical MR lesions were seen with concordant PET findings. The remaining patient revealed a new abnormal PET lesion without an MR abnormality. All new PET/MR lesions were clinically significant with concordant EEG and/or SPECT results as potential epileptic foci. Our initial hybrid PET-MRI experience increased diagnostic yields for detection of potential epileptic lesions. This may be due to the unique advantage of improved co-registration and simultaneous review of both structural and functional data. Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  1. Initial constructs for patient-centered outcome measures to evaluate brain-computer interfaces.

    Science.gov (United States)

    Andresen, Elena M; Fried-Oken, Melanie; Peters, Betts; Patrick, Donald L

    2016-10-01

    The authors describe preliminary work toward the creation of patient-centered outcome (PCO) measures to evaluate brain-computer interface (BCI) as an assistive technology (AT) for individuals with severe speech and physical impairments (SSPI). In Phase 1, 591 items from 15 existing measures were mapped to the International Classification of Functioning, Disability and Health (ICF). In Phase 2, qualitative interviews were conducted with eight people with SSPI and seven caregivers. Resulting text data were coded in an iterative analysis. Most items (79%) were mapped to the ICF environmental domain; over half (53%) were mapped to more than one domain. The ICF framework was well suited for mapping items related to body functions and structures, but less so for items in other areas, including personal factors. Two constructs emerged from qualitative data: quality of life (QOL) and AT. Component domains and themes were identified for each. Preliminary constructs, domains and themes were generated for future PCO measures relevant to BCI. Existing instruments are sufficient for initial items but do not adequately match the values of people with SSPI and their caregivers. Field methods for interviewing people with SSPI were successful, and support the inclusion of these individuals in PCO research. Implications for Rehabilitation Adapted interview methods allow people with severe speech and physical impairments to participate in patient-centered outcomes research. Patient-centered outcome measures are needed to evaluate the clinical implementation of brain-computer interface as an assistive technology.

  2. Economic evaluation of 'Return to Country': A remote Australian initiative to address indigenous homelessness.

    Science.gov (United States)

    Kinchin, Irina; Jacups, Susan; Hunter, Gary; Rogerson, Bernadette

    2016-06-01

    An increase in the number of Indigenous homeless persons in Cairns, Northern Australia, prompted the Queensland Police Service (QPS) to commence a pilot 'Return to Country' (R2C) program. The program was designed to assist homeless people who were voluntarily seeking to return to their home communities. This study assesses the costs of running the program and evaluates its net economic impact. Retrospective uncontrolled cost, cost-effectiveness and cost-offset analyses were undertaken from a societal perspective. All costs were expressed in 2014 AU$. The R2C program successfully assisted 140 participants to return home, reducing the prevalence of homelessness in the regional center by 9.6%. The total program cost was estimated as AU$ 135,831 or AU$ 970 per participant. The economic analysis indicated that R2C was value for money, potentially saving AU$ 2,714,460. Limitations of the study included retrospective data collection and no established alternative comparison group. R2C is a relatively simple, minimal cost program, which can be utilized by policy makers to offer one solution to homelessness. This economic evaluation informs the QPS of the effects of the R2C program in order to guide further program initiatives. The R2C model may be applied to assist temporarily stranded Indigenous people in other locations within Australia or internationally to return home. No funding was obtained for conducting this study. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Role of skull radiography in the initial evaluation of minor head injury: a retrospective study

    International Nuclear Information System (INIS)

    Murshid, W.R.

    1994-01-01

    The use of skull radiography in the initial evaluation of minor head injured patients is controversial. In an attempt to evaluate its benefits, a retrospective study of 566 cases subjected to skull radiography following close minor head trauma (Glasgow Coma Scale 13-15), is presented. A skull fracture (linear vault, depressed or base of skull) was present in 64 (11%) cases. Only three (5%) who were found to have a skull fracture on skull radiography developed an intracranial injury which required surgery. Intracranial injuries developed in 19 (3%) cases and were followed by surgery in six (32%). All, except for one case, had a decreased level of consciousness and a Glasgow Coma Scale less than 15, few had focal neurological deficits. Management had not been altered by the results of skull radiography in any of the cases. We concluded that skull radiographs are unnecessary for the decision process in closed minor head injury because management decisions are based primarily on a careful neurological examination. When intracranial injuries are a concern, a CT scan should be obtained. (author)

  4. A web-based application for initial screening of living kidney donors: development, implementation and evaluation.

    Science.gov (United States)

    Moore, D R; Feurer, I D; Zavala, E Y; Shaffer, D; Karp, S; Hoy, H; Moore, D E

    2013-02-01

    Most centers utilize phone or written surveys to screen candidates who self-refer to be living kidney donors. To increase efficiency and reduce resource utilization, we developed a web-based application to screen kidney donor candidates. The aim of this study was to evaluate the use of this web-based application. Method and time of referral were tabulated and descriptive statistics summarized demographic characteristics. Time series analyses evaluated use over time. Between January 1, 2011 and March 31, 2012, 1200 candidates self-referred to be living kidney donors at our center. Eight hundred one candidates (67%) completed the web-based survey and 399 (33%) completed a phone survey. Thirty-nine percent of donors accessed the application on nights and weekends. Postimplementation of the web-based application, there was a statistically significant increase (p web-based application as opposed to telephone contact. Also, there was a significant increase (p = 0.025) in the total number of self-referrals post-implementation from 61 to 116 per month. An interactive web-based application is an effective strategy for the initial screening of donor candidates. The web-based application increased the ability to interface with donors, process them efficiently and ultimately increased donor self-referral at our center. © Copyright 2012 The American Society of Transplantation and the American Society of Transplant Surgeons.

  5. The development and initial assessment of the strategy and leadership systems capability evaluation survey.

    Science.gov (United States)

    Coon, Cheryl D; Bokowy, Kay L; Horblyuk, Ruslan; Zisman, Robert S; McLeod, Lori D; Brown, T Michelle

    2012-01-01

    Hospital management and leadership systems are associated with organizational success and quality care. The Strategy and Leadership Systems Capability Evaluation (CE) survey was developed by GE Healthcare to assess management and leadership systems at health care institutions, serve as a benchmark for improvement, and measure progress. To assess the psychometric properties of the 29-item CE survey, including the factor structure, scoring algorithm, reliability, and discriminant validity, an online survey was completed by 3450 employees at 15 US hospitals. Of these employees, 609 worked at a hospital where a leadership and management intervention occurred after the initial survey administration. Data were also collected on job level, number of hospital beds, hospital ownership, location, community type, and the implementation of hospital interventions. Item response frequencies showed no floor or ceiling effects and limited missing data. Interitem correlations were strong without obvious redundancies, and factor analysis suggested a unidimensional scale. The resulting scale had strong internal consistency and was able to discriminate among known groups. The CE survey was developed to evaluate management and leadership systems at health care institutions. This study provides psychometric evidence in support of the reliability, validity, and scoring structure of this survey.

  6. SU-F-T-180: Evaluation of a Scintillating Screen Detector for Proton Beam QA and Acceptance Testing

    Energy Technology Data Exchange (ETDEWEB)

    Ghebremedhin, A; Taber, M; Koss, P; Camargo, G; Patyal, B [Loma Linda University Medical Center, Loma Linda, CA (United States); Ebstein, S [Lexitek, Inc, Wellesley, MA (United States)

    2016-06-15

    Purpose: To test the performance of a commercial scintillating screen detector for acceptance testing and Quality Assurance of a proton pencil beam scanning system. Method: The detector (Lexitek DRD 400) has 40cm × 40cm field, uses a thin scintillator imaged onto a 16-bit scientific CCD with ∼0.5mm resolution. A grid target and LED illuminators are provided for spatial calibration and relative gain correction. The detector mounts to the nozzle with micron precision. Tools are provided for image processing and analysis of single or multiple Gaussian spots. Results: The bias and gain of the detector were studied to measure repeatability and accuracy. Gain measurements were taken with the LED illuminators to measure repeatability and variation of the lens-CCD pair as a function with f-stop. Overall system gain was measured with a passive scattering (broad) beam whose shape is calibrated with EDR film placed in front of the scintillator. To create a large uniform field, overlapping small fields were recorded with the detector translated laterally and stitched together to cover the full field. Due to the long exposures required to obtain multiple spills of the synchrotron and very high detector sensitivity, borated polyethylene shielding was added to reduce direct radiation events hitting the CCD. Measurements with a micro ion chamber were compared to the detector’s spot profile. Software was developed to process arrays of Gaussian spots and to correct for radiation events. Conclusion: The detector background has a fixed bias, a small component linear in time, and is easily corrected. The gain correction method was validated with 2% accuracy. The detector spot profile matches the micro ion chamber data over 4 orders of magnitude. The multiple spot analyses can be easily used with plan data for measuring pencil beam uniformity and for regular QA comparison.

  7. SU-F-T-180: Evaluation of a Scintillating Screen Detector for Proton Beam QA and Acceptance Testing

    International Nuclear Information System (INIS)

    Ghebremedhin, A; Taber, M; Koss, P; Camargo, G; Patyal, B; Ebstein, S

    2016-01-01

    Purpose: To test the performance of a commercial scintillating screen detector for acceptance testing and Quality Assurance of a proton pencil beam scanning system. Method: The detector (Lexitek DRD 400) has 40cm × 40cm field, uses a thin scintillator imaged onto a 16-bit scientific CCD with ∼0.5mm resolution. A grid target and LED illuminators are provided for spatial calibration and relative gain correction. The detector mounts to the nozzle with micron precision. Tools are provided for image processing and analysis of single or multiple Gaussian spots. Results: The bias and gain of the detector were studied to measure repeatability and accuracy. Gain measurements were taken with the LED illuminators to measure repeatability and variation of the lens-CCD pair as a function with f-stop. Overall system gain was measured with a passive scattering (broad) beam whose shape is calibrated with EDR film placed in front of the scintillator. To create a large uniform field, overlapping small fields were recorded with the detector translated laterally and stitched together to cover the full field. Due to the long exposures required to obtain multiple spills of the synchrotron and very high detector sensitivity, borated polyethylene shielding was added to reduce direct radiation events hitting the CCD. Measurements with a micro ion chamber were compared to the detector’s spot profile. Software was developed to process arrays of Gaussian spots and to correct for radiation events. Conclusion: The detector background has a fixed bias, a small component linear in time, and is easily corrected. The gain correction method was validated with 2% accuracy. The detector spot profile matches the micro ion chamber data over 4 orders of magnitude. The multiple spot analyses can be easily used with plan data for measuring pencil beam uniformity and for regular QA comparison.

  8. Evaluation of PET Imaging Resolution Using 350 mu{m} Pixelated CZT as a VP-PET Insert Detector

    Science.gov (United States)

    Yin, Yongzhi; Chen, Ximeng; Li, Chongzheng; Wu, Heyu; Komarov, Sergey; Guo, Qingzhen; Krawczynski, Henric; Meng, Ling-Jian; Tai, Yuan-Chuan

    2014-02-01

    A cadmium-zinc-telluride (CZT) detector with 350 μm pitch pixels was studied in high-resolution positron emission tomography (PET) imaging applications. The PET imaging system was based on coincidence detection between a CZT detector and a lutetium oxyorthosilicate (LSO)-based Inveon PET detector in virtual-pinhole PET geometry. The LSO detector is a 20 ×20 array, with 1.6 mm pitches, and 10 mm thickness. The CZT detector uses ac 20 ×20 ×5 mm substrate, with 350 μm pitch pixelated anodes and a coplanar cathode. A NEMA NU4 Na-22 point source of 250 μm in diameter was imaged by this system. Experiments show that the image resolution of single-pixel photopeak events was 590 μm FWHM while the image resolution of double-pixel photopeak events was 640 μm FWHM. The inclusion of double-pixel full-energy events increased the sensitivity of the imaging system. To validate the imaging experiment, we conducted a Monte Carlo (MC) simulation for the same PET system in Geant4 Application for Emission Tomography. We defined LSO detectors as a scanner ring and 350 μm pixelated CZT detectors as an insert ring. GATE simulated coincidence data were sorted into an insert-scanner sinogram and reconstructed. The image resolution of MC-simulated data (which did not factor in positron range and acolinearity effect) was 460 μm at FWHM for single-pixel events. The image resolutions of experimental data, MC simulated data, and theoretical calculation are all close to 500 μm FWHM when the proposed 350 μm pixelated CZT detector is used as a PET insert. The interpolation algorithm for the charge sharing events was also investigated. The PET image that was reconstructed using the interpolation algorithm shows improved image resolution compared with the image resolution without interpolation algorithm.

  9. Evaluation of the influence of the TH-GEM detector components in dosimetric measurements of standard mammography beams

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Natália F.; Castro, Maysa C.; Caldas, Linda V.E., E-mail: nsilva@ipen.br, E-mail: maysadecastro@gmail.com, E-mail: fbelonsi@gmail.com, E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Silva, Tiago F.; Cintra, Felipe B.; Luz, Hugo N. da, E-mail: tfsilva@if.usp.br, E-mail: hugonluz@if.usp.br [Universidade de São Paulo (IF/USP), São Paulo, SP (Brazil). Instituto de Física

    2017-07-01

    GEM detectors have found applications in many areas due to their simplicity of construction, low cost, ruggedness and diversity of shape. A dosimeter with these qualities presents utility in several applications, as for example in diagnostic and therapeutic medicine, industrial radiography and nuclear meters. Furthermore, the high sensitivity provided by GEM detectors may extend their applications in low dose dosimetry. Based on these facts, it may be interesting to produce a prototype of a portable TH-GEM type detector with characteristics suitable for dosimetric use in X-rays with low and medium energies. The precise determination of the dosimeter characteristics is very important for laboratories of instrument calibration, as well as to determine how the various components of the detector may influence on the energy deposited in the sensitive volume. In this work, the results obtained about the influence of each one of the components present in this type of detector in standard mammography beams is presented. The code MCNP5 was used. The results allowed the adaptation of the detector to the desired conditions. (author)

  10. Evaluation of slow shutdown system flux detectors in Point Lepreau Generating Station - II: dynamic compensation error analysis

    Energy Technology Data Exchange (ETDEWEB)

    Anghel, V.N.P.; Sur, B. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Taylor, D. [New Brunswick Power Nuclear, Point Lepreau, New Brunswick (Canada)

    2009-07-01

    CANDU reactors are protected against reactor overpower by two independent shutdown systems: Shut Down System 1 and 2 (SDS1 and SDS2). At the Point Lepreau Generating Station (PLGS), the shutdown systems can be actuated by measurements of the neutron flux from Platinum-clad Inconel In-Core Flux Detectors. These detectors have a complex dynamic behaviour, characterized by 'prompt' and 'delayed' components with respect to immediate changes in the in-core neutron flux. It was shown previously (I: Dynamic Response Characterization by Anghel et al., this conference) that the dynamic responses of the detectors changed with irradiation, with the SDS2 detectors having 'prompt' signal components that decreased significantly. In this paper we assess the implication of these changes for detector dynamic compensation errors by comparing the compensated detector response with the power-to-fuel and the power-to-coolant responses to neutron flux ramps as assumed by previous error analyses. The dynamic compensation error is estimated at any given trip time for all possible accident flux ramps. Some implications for the shutdown system trip set points, obtained from preliminary results, are discussed. (author)

  11. Criteria for evaluating programme theory diagrams in quality improvement initiatives: a structured method for appraisal.

    Science.gov (United States)

    Issen, Laurel; Woodcock, Thomas; McNicholas, Christopher; Lennox, Laura; Reed, Julie E

    2018-04-09

    Despite criticisms that many quality improvement (QI) initiatives fail due to incomplete programme theory, there is no defined way to evaluate how programme theory has been articulated. The objective of this research was to develop, and assess the usability and reliability of scoring criteria to evaluate programme theory diagrams. Criteria development was informed by published literature and QI experts. Inter-rater reliability was tested between two evaluators. About 63 programme theory diagrams (42 driver diagrams and 21 action-effect diagrams) were reviewed to establish whether the criteria could support comparative analysis of different approaches to constructing diagrams. Components of the scoring criteria include: assessment of overall aim, logical overview, clarity of components, cause-effect relationships, evidence and measurement. Independent reviewers had 78% inter-rater reliability. Scoring enabled direct comparison of different approaches to developing programme theory; action-effect diagrams were found to have had a statistically significant but moderate improvement in programme theory quality over driver diagrams; no significant differences were observed based on the setting in which driver diagrams were developed. The scoring criteria summarise the necessary components of programme theory that are thought to contribute to successful QI projects. The viability of the scoring criteria for practical application was demonstrated. Future uses include assessment of individual programme theory diagrams and comparison of different approaches (e.g. methodological, teaching or other QI support) to produce programme theory. The criteria can be used as a tool to guide the production of better programme theory diagrams, and also highlights where additional support for QI teams could be needed.

  12. Performance Evaluation of State-of-the-Art Local Feature Detectors and Descriptors in the Context of Longitudinal Registration of Retinal Images.

    Science.gov (United States)

    Saha, Sajib K; Xiao, Di; Frost, Shaun; Kanagasingam, Yogesan

    2018-02-17

    In this paper we systematically evaluate the performance of several state-of-the-art local feature detectors and descriptors in the context of longitudinal registration of retinal images. Longitudinal (temporal) registration facilitates to track the changes in the retina that has happened over time. A wide number of local feature detectors and descriptors exist and many of them have already applied for retinal image registration, however, no comparative evaluation has been made so far to analyse their respective performance. In this manuscript we evaluate the performance of the widely known and commonly used detectors such as Harris, SIFT, SURF, BRISK, and bifurcation and cross-over points. As of descriptors SIFT, SURF, ALOHA, BRIEF, BRISK and PIIFD are used. Longitudinal retinal image datasets containing a total of 244 images are used for the experiment. The evaluation reveals some potential findings including more robustness of SURF and SIFT keypoints than the commonly used bifurcation and cross-over points, when detected on the vessels. SIFT keypoints can be detected with a reliability of 59% for without pathology images and 45% for with pathology images. For SURF keypoints these values are respectively 58% and 47%. ALOHA descriptor is best suited to describe SURF keypoints, which ensures an overall matching accuracy, distinguishability of 83%, 93% and 78%, 83% for without pathology and with pathology images respectively.

  13. A Porcine Model for Initial Surge Mechanical Ventilator Assessment and Evaluation of Two Limited Function Ventilators

    Science.gov (United States)

    Dickson, Robert P; Hotchkin, David L; Lamm, Wayne JE; Hinkson, Carl; Pierson, David J; Glenny, Robb W; Rubinson, Lewis

    2013-01-01

    Objective To adapt an animal model of acute lung injury for use as a standard protocol for a screening, initial evaluation of limited function, or “surge,” ventilators for use in mass casualty scenarios. Design Prospective, experimental animal study. Setting University research laboratory. Subjects 12 adult pigs. Interventions 12 spontaneously breathing pigs (6 in each group) were subjected to acute lung injury/acute respiratory distress syndrome (ALI/ARDS) via pulmonary artery infusion of oleic acid. Following development of respiratory failure, animals were mechanically ventilated with a limited function ventilator (Simplified Automatic Ventilator [SAVe] I or II; Automedx) for one hour or until the ventilator could not support the animal. The limited function ventilator was then exchanged for a full function ventilator (Servo 900C; Siemens). Measurements and Main Results Reliable and reproducible levels of ALI/ARDS were induced. The SAVe I was unable to adequately oxygenate 5 animals, with PaO2 (52.0 ± 11.1 torr) compared to the Servo (106.0 ± 25.6 torr; p=0.002). The SAVe II was able to oxygenate and ventilate all 6 animals for one hour with no difference in PaO2 (141.8 ± 169.3 torr) compared to the Servo (158.3 ± 167.7 torr). Conclusions We describe a novel in vivo model of ALI/ARDS that can be used to initially screen limited function ventilators considered for mass respiratory failure stockpiles, and is intended to be combined with additional studies to defintively assess appropriateness for mass respiratory failure. Specifically, during this study we demonstrate that the SAVe I ventilator is unable to provide sufficient gas exchange, while the SAVe II, with several more functions, was able to support the same level of hypoxemic respiratory failure secondary to ALI/ARDS for one hour. PMID:21187747

  14. Evaluation of the initial and final radiological status of a nuclear facility in sanitation status

    International Nuclear Information System (INIS)

    Granier, Guy; Aubonnet, Emilie; Courbet, Christele; Desnoyers, Yvon; Dubot, Didier; Fichet, Pascal; Nokhamzon, Jean-Guy; Ollivier Dehaye, Catherine; Pillette-Cousin, Lucien; Mahe, Charly

    2017-02-01

    This technical report is a guideline for radiological assessment of a nuclear facility in remediation stages. From initial state of remediation to final status survey it describes the best suited statistical or geostatistical approach for the characterization of sites contaminated by radionuclides. Prior to any characterization campaign an historical analysis coupled with a function analysis targeted investigations is fundamental to obtain a robust overview. The evaluation of the amount of radioactive material present in a defined area requires a sampling strategy correlated with characterization objective. On the other hand correlation between remediation objectives and characterization objectives also requires knowing acceptable level of risk. This give better inputs to allow available resources and take into account environmental constraints. In particular, radiological characterization of infrastructures is one of the key step to conduct industrial project of decommissioning nuclear facilities in remediation. It needs a reliable initial diagnosis to obtain an efficient waste management with a financial control Optimization of the production of nuclear waste. It is an important part of Setting the Off Final - Dismantling). This approach is compatible with French Regulation (Guide 14 ASN) for the first and second line of defence. Annexes provide feedback of experimentation of this methodology. This report supplements the methodological guide published by the GT10 CETAMA entitled 'Soil Radiological Characterisation Methodology' (CEA-R 6386). The latter is intended for project managers and covers all issues related to the characterization projects for soil. This guideline concern specifically design engineers in charge of implementation program at the different stages of investigation and data processing. Similarly, the proposed methodology can be broken for the characterization of chemical pollution and process equipment. (authors)

  15. Evaluation of a well-established task-shifting initiative: the lay counselor cadre in Botswana.

    Science.gov (United States)

    Ledikwe, Jenny H; Kejelepula, Mable; Maupo, Kabelo; Sebetso, Siwulani; Thekiso, Mothwana; Smith, Monica; Mbayi, Bagele; Houghton, Nankie; Thankane, Kabo; O'Malley, Gabrielle; Semo, Bazghina-Werq

    2013-01-01

    Evidence supports the implementation of task shifting to address health worker shortages that are common in resource-limited settings. However, there is need to learn from established programs to identify ways to achieve the strongest, most sustainable impact. This study examined the Botswana lay counselor cadre, a task shifting initiative, to explore effectiveness and contribution to the health workforce. This evaluation used multiple methods, including a desk review, a national lay counselor survey (n = 385; response = 94%), in-depth interviews (n = 79), lay counselors focus group discussions (n = 7), lay counselors observations (n = 25), and client exit interviews (n = 47). Interview and focus group data indicate that lay counselors contribute to essentially all HIV-related programs in Botswana and they conduct the majority of HIV tests and related counseling at public health facilities throughout the country. Interviews showed that the lay counselor cadre is making the workload of more skilled health workers more manageable and increasing HIV acceptance in communities. The average score on a work-related knowledge test was 74.5%. However for 3 questions, less than half answered correctly. During observations, lay counselors demonstrated average competence for most skills assessed and clients (97.9%) were satisfied with services received. From the survey, lay counselors generally reported being comfortable with their duties; however, some reported clinical duties that extended beyond their training and mandate. Multiple factors affecting the performance of the lay counselors were identified, including insufficient resources, such as private counseling space and HIV test kits; and technical, administrative, and supervisory support. Lay counselors are fulfilling an important role in Botswana's healthcare system, serving as the entry point into HIV care, support, and treatment services. For this and other similar task shifting initiatives

  16. The utility of plain radiographs in the initial evaluation of knee pain amongst sports medicine patients.

    Science.gov (United States)

    Alaia, Michael J; Khatib, Omar; Shah, Mehul; A Bosco, Joseph; M Jazrawi, Laith; Strauss, Eric J

    2015-08-01

    To evaluate whether screening radiographs as part of the initial workup of knee pain impacts clinical decision-making in a sports medicine practice. A questionnaire was completed by the attending orthopaedic surgeon following the initial office visit for 499 consecutive patients presenting to the sports medicine centre with a chief complaint of knee pain. The questionnaire documented patient age, duration of symptoms, location of knee pain, associated mechanical symptoms, history of trauma within the past 2 weeks, positive findings on plain radiographs, whether magnetic resonance imaging was ordered, and whether plain radiographs impacted the management decisions for the patient. Patients were excluded if they had prior X-rays, history of malignancy, ongoing pregnancy, constitutional symptoms as well as those patients with prior knee surgery or intra-articular infections. Statistical analyses were then performed to determine which factors were more likely do correspond with diagnostic radiographs. Overall, initial screening radiographs did not change management in 72 % of the patients assessed in the office. The mean age of patients in whom radiographs did change management was 57.9 years compared to 37.1 years in those patients where plain radiograph did not change management (p < 0.0001). Plain radiographs had no impact on clinical management in 97.3 % of patients younger than 40. In patients whom radiographs did change management, radiographs were more likely to influence management if patients were over age forty, had pain for over 6 months, had medial or diffuse pain, or had mechanical symptoms. A basic cost analysis revealed that the cost of a clinically useful radiographic series in a patient under 40 years of age was $7,600, in contrast to $413 for a useful series in patients above the age of 40. Data from the current study support the hypothesis that for the younger patient population, routine radiographic imaging as a screening tool may be of

  17. SU-G-TeP2-08: Evaluation of Plastic Scintillator Detector for Small Field Stereotactic Patient-Specific Quality Assurance

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Y; Gardner, S; Huang, Y; Kim, J; Wen, N; Chetty, I [Henry Ford Health System, Detroit, MI (United States)

    2016-06-15

    Purpose: To evaluate the performance of a commercial plastic scintillator detector (PSD) for small-field stereotactic patient-specific quality assurance using flattening-filter-free (FFF) beams. Methods: A total of ten spherical targets (volume range:[0.03cc–2cc]) were planned using Dynamic Conformal Arc(DCA-10 plans) and Volumetric Modulated Arc Therapy(VMAT-10 plans) techniques in Eclipse(AAA v.11, 1mm dose calculation grid size). Additionally, 15 previously-treated cranial and spine SRS plans were evaluated (6 DCA, 9 VMAT, volume range:[0.04cc–119.02cc]). All measurements were acquired using Varian Edge equipped with HDMLC. Three detectors were used: PinPoint ion chamber (PTW;active volume 0.015cc), Exradin W1 PSD (Standard Imaging;active volume 0.002cc), and Gafchromic EBT3 film (Ashland). PinPoint and PSD were positioned perpendicular to beam axis in a Lucy phantom (Standard Imaging). Films were placed at isocenter in solid water. Calibration films were delivered for absolute dose analysis. Results: For large spherical targets(>1.5cc) with DCA, all detectors agreed within 1% of AAA calculations. As target volume decreased, PSD measured higher doses than AAA (maximum difference: 3.3% at 0.03cc target), while PinPoint chamber measured lower doses (maximum difference:-3.8% at 0.03cc target). Inter-detector differences between pinpoint and PSD increased with decreasing target size; differences>5% were observed for targets<0.09cc. Similar trends for inter-detector behavior were observed for clinical plans. For target sizes<0.08cc, PSD measured>5% higher dose than PinPoint chamber (maximum difference: 9.25% at 0.04cc target). Film demonstrated agreement of −0.19±1.47% with PSD for all spherical targets, and agreement within −0.98±2.25% for all 15 clinical targets. Unlike DCA, VMAT plans did not show improved AAA-to-detector agreements for large targets. Conclusion: For all targets, the PSD measurements agreed with film within 1.0%, on average. For small

  18. Evaluation the image obtained from X-ray flat-panel detectors utilizing a polycrystalline CdZnTe film as the conversion layer

    International Nuclear Information System (INIS)

    Tokuda, S.; Kishihara, H.; Kaino, M.; Sato, T.

    2006-01-01

    We can expect that fluoroscopic images with a high sensitivity and excellent detective efficiency can be obtained by using a semiconductor with a small W factor for the conversion layer of X-ray flat-panel detectors, which have experienced a rapid gain inpopularity for medical and non-destructive industrial inspection uses in recent years. We believe that polycrystalline CdZnTe film formed by the closed spaced sublimation (CSS) method is a promising conversion material for next-generation high efficiency X-ray flat-panel detectors, and have previously reported the results of feasibility studies. In this paper, we present an overview of X-ray flat-panel detectors and the features of CdZnTe film, then we describe the CSS method of deposition and evaluation of the physical characteristics of CdZnTe film, and finally we present the results of our fabrication and testing of proto-type detectors utilizing CdZnTe film. (author)

  19. The use of multi-energy-group neutron diffusion theory to numerically evaluate the relative utility of three dial-detector neutron porosity well logging tools

    International Nuclear Information System (INIS)

    Zalan, T.A.

    1988-01-01

    Multi-energy-group neutron diffusion theory is used to numerically evaluate the utility of two different dual-detector neutron porosity logging devices, a 14 MeV (accelerator) neutron source - epithermal neutron detector device and a 4 MeV neutron source - capture gamma-ray detector device, relative to the traditional 4 MeV neutron source - thermal neutron detector device. Fast and epithermal neutron diffusion parameters are calculated using Monte Carlo - derived neutron flux distributions. Thermal parameters are calculated from tabulated cross sections. An existing analytical method to describe the transport of gamma-rays through common earth materials is modified in order to accommodate the modeling of the 4 MeV neutron - capture gamma-ray device. The 14 MeV neutron - epithermal neutron device is found to be less sensitive to porosity than the 4 MeV neutron - capture gamma-ray device, which in turn is found to be less sensitive to porosity than the traditional 4 MeV neutron - thermal neutron device. Salinity effects are found to be comparable for the 4 MeV neutron - capture gamma-ray and 4 MeV neutron - thermal neutron devices. The 4 MeV neutron capture gamma-ray measurement is found to be deepest investigating

  20. Mobile Landing Platform with Core Capability Set (MLP w/CCS): Combined Initial Operational Test and Evaluation and Live Fire Test and Evaluation Report

    Science.gov (United States)

    2015-07-01

    SUBTITLE Mobile Landing Platform with Core Capability Set (MLP w/CCS) Combined Initial Operational Test and Evaluation ( IOT &E) and Live Fire Test and...based on data from a series of integrated test events, a dedicated end-to-end Initial Operational Test and Evaluation ( IOT &E), and two Marine Corps...Internally Transportable Vehicles (ITVs).   ii the LMSR to anchor within a few miles of the shore. Using MLP (CCS), the equipment is transported ashore

  1. Diagnostic Accuracy of Ultrasonography in the Initial Evaluation of Patients with Penetrating Chest Trauma

    Directory of Open Access Journals (Sweden)

    Farhad Heydari

    2014-03-01

    Full Text Available Introduction: Traumatic chest injuries (TCI are one of the most common causes of referring to the emergency departments, with high mortality and disability. This study was designed to evaluate the diagnostic accuracy of ultrasonography versus chest X ray (CXR in detection of hemo-pneumothorax for patients suffering penetrating TCI. Methods: The present cross-sectional study was performed to evaluate the diagnostic accuracy of ultrasonography in penetrating TCI victims referred to the emergency department of Shahid Kashani and Alzahra hospitals of Isfahan, Iran, from July 2012 to June 2013. Bedside ultrasonography and plain CXR was done on arrival and three hours after admission. The results of ultrasonography and radiography were separately evaluated by an emergency medicine specialist and a radiologist, who were blind to the aims of the study. Then, sensitivity, specificity, positive predictive value (PPV, negative predictive value (NPV, and kappa coefficient was considered to evaluate the accuracy of ultrasonography. Results: In this research 64 patients with penetrating chest trauma were assessed (98.4% male. The mean age of them was 25.6±8.5 years (rang: 13-65. The plain radiography revealed the eight (12.5 % cases of pneumothorax and one (1.6% hemothorax. The findings of primary ultrasonography also showed the same number of hemo-pneumothorax. Sensitivity and specificity of primary ultrasound in diagnosis of pneumothorax were 100% (95% Cl: 60.7- 100 and 100.0% (95% Cl, 92.0% to 100.0% and in detection of hemothorax were 100% (95% Cl: 50.5-100 and 100% (95% Cl: 92.8-100, respectively. Sensitivity and specificity of ultrasound in the third hour were 100% (95% Cl: 31.3-100 and 100% (95% Cl: 91.4-100, respectively. Conclusion: Findings of the present study have shown that ultrasonography has an acceptable diagnostic accuracy in the initial assessment of patients with penetrating chest trauma. However, because of its dependency on operator

  2. Wire Probe Antenna (WPT) and Electric Field Detector (EFD0 of Plasma Wave Experiment (PWE) aboard ARASE: Specifications and Evaluation results

    Science.gov (United States)

    Matsuda, S.; Kasaba, Y.; Ishisaka, K.; Kasahara, Y.; Imachi, T.; Yagitani, S.; Kojima, H.; Kurita, S.; Shoji, M.; Hori, T.; Shinbori, A.; Teramoto, M.; Miyoshi, Y.; Nakagawa, T.; Takahashi, N.; Nishimura, Y.; Matsuoka, A.; Tsuchiya, F.; Kumamoto, A.; Nomura, R.

    2017-12-01

    This paper summarizes the specifications and the evaluation results of Wire Probe Antenna (WPT) and Electric Field Detector (EFD), which are the key parts of Plasma Wave Experiment (PWE) aboard the Arase satellite, in their initial operations and the beginning phase of the full observations. WPT consists of the two dipole antennas as electric field sensors with 32m tip-to-tip length, with a sphere probe (6 cm diameter) attached at each end of wires (length: 15-m). They are extended orthogonally in the spin plane which is roughly perpendicular to the Sun. It enables the PWE to measure the E-field from DC to 10 MHz. This system is almost compatible to the WPT of the Plasma Wave Investigation (PWI) aboard BepiColombo Mercury Magnetospheric Orbiter, except the material of the spherical probe (ERG: Aluminium alloy, MMO: Titanium-alloy). This paper shows the extended length evaluated by the Lorentz force (spacecraft velocity x B-field) and the antenna impedance as the basic information of the E-field measurement capability of the PWE E-field receivers, with the evaluation for the possible degradation of the probe surface coated by TiAlN as BepiColombo. EFD is the 2-channel low frequency electric receiver as a part of EWO (EFD/WFC/OFA), for the measurement of 2ch electric field in the spin-plane with the sampling rate of 512 Hz (dynamic range: +-200 mV/m, +-3 V/m) and the 4ch spacecraft potential with the sampling rate of 128 Hz (dynamic range: +-100 V), respectively, with the bias control capability fed to the WPT probes. The electric field in DC - 232Hz provides the capability to detect (1) the fundamental information of the plasma dynamics and accelerations and (2) the characteristics of MHD and ion waves with their Poynting vectors with the data measured by MGF and PWE/WFC-B connected to PWE/SCM. The spacecraft potential provides the electron density information with UHR frequency. This paper also introduces the data sets and their calibration status.

  3. The Effects of a Statewide Evaluation Initiative in Gifted Education on Practitioner Knowledge, Concerns, and Program Documentation

    Science.gov (United States)

    Robinson, Ann; Cotabish, Alicia; Wood, Betty K.; O'Tuel, Fran S.

    2014-01-01

    When well-considered and grounded in current knowledge, program evaluations of services to gifted learners can be a powerful tool for increasing practitioners' knowledge and self-efficacy, and for effecting positive programmatic changes. The Arkansas Evaluation Initiative (AEI) in Gifted Education, a Jacob K. Javits-funded project, was implemented…

  4. Initial evaluation of the Robert Wood Johnson Foundation Nurse Faculty Scholars program.

    Science.gov (United States)

    Hickey, Kathleen T; Hodges, Eric A; Thomas, Tami L; Coffman, Maren J; Taylor-Piliae, Ruth E; Johnson-Mallard, Versie M; Goodman, Janice H; Jones, Randy A; Kuntz, Sandra; Galik, Elizabeth; Gates, Michael G; Casida, Jesus M

    2014-01-01

    The Robert Wood Johnson Foundation Nurse Faculty Scholars (RWJF NFS) program was developed to enhance the career trajectory of young nursing faculty and to train the next generation of nurse scholars. Although there are publications that describe the RWJF NFS, no evaluative reports have been published. The purpose of this study was to evaluate the first three cohorts (n = 42 scholars) of the RWJF NFS program. A descriptive research design was used. Data were derived from quarterly and annual reports, and a questionnaire (seven open-ended questions) was administered via Survey Monkey Inc. (Palo Alto, CA, USA). During their tenure, scholars had on average six to seven articles published, were teaching/mentoring at the graduate level (93%), and holding leadership positions at their academic institutions (100%). Eleven scholars (26%) achieved fellowship in the American Academy of Nursing, one of the highest nursing honors. The average ratings on a Likert scale of 1 (not at all supportive) to 10 (extremely supportive) of whether or not RWJF had helped scholars achieve their goals in teaching, service, research, and leadership were 7.7, 8.0, 9.4, and 9.5, respectively. The majority of scholars reported a positive, supportive relationship with their primary nursing and research mentors; although, several scholars noted challenges in connecting for meetings or telephone calls with their national nursing mentors. These initial results of the RWJF NFS program highlight the success of the program in meeting its overall goal-preparing the next generation of nursing academic scholars for leadership in the profession. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. An Initial evaluation of law enforcement overdose training in Rhode Island.

    Science.gov (United States)

    Saucier, Cory D; Zaller, Nickolas; Macmadu, Alexandria; Green, Traci C

    2016-05-01

    To assess initial change in knowledge, self-efficacy, and anticipated behaviors among Rhode Island law enforcement officers on drug overdose response and prevention. Law enforcement officers (N=316) voluntarily completed a pre-post evaluation immediately before and after taking part in overdose prevention and response trainings. Assessment items included measures of knowledge (Brief Overdose Recognition and Response Assessment (BORRA)), self-efficacy, attitudes toward drugs and overdose prevention, awareness of the Good Samaritan Law, and open-ended items pertaining to overdose knowledge and response behaviors. Non-parametric tests measured within-group and between-group differences. Wilcoxon Signed Rank tests and Kruskal-Wallis tests evaluated changes in BORRA scores and self-efficacy items. McNemar's tests assessed changes regarding the Good Samaritan law and open-ended items. Wilcoxon Signed Rank tests measured post-training change in attitudes. Law enforcement officers demonstrated statistically significant improvements in self-efficacy (identifying signs of opioid overdose, naloxone indication, counseling witnesses in overdose prevention, and referring witnesses for more information), overdose identification knowledge (BORRA mean increased from 7.00 to 10.39), naloxone administration knowledge (BORRA mean increased from 10.15 to 12.59), Good Samaritan Law awareness (17.9% increase after training), and anticipated behaviors in response to future observed overdose (65.7% changed from passive to active response post training). Harm reduction programs can provide law enforcement officers with the knowledge and skills necessary to intervene and reduce overdose mortality. Given the statistically significant improvements in self-efficacy, attitudinal changes, and Good Samaritan law awareness, law enforcement officers are more prepared to actively interact with drug users during a drug-involved emergency. Copyright © 2016. Published by Elsevier Ireland Ltd.

  6. Enhanced evaluation data initiates a collaborative out-of-school time food sponsors work group.

    Science.gov (United States)

    Rifkin, Robin; Williams, Lauren A; Grode, Gabrielle M; Roberts-Johnson, Wendy-Anne

    2015-01-01

    Philadelphia's Healthy Kids, Healthy Communities Out-of-School Time (OST) Initiative led by the Health Promotion Council developed 10 Healthy Living Guidelines for Out-of-School Time Programs to support a healthy environment for Philadelphia youth in 200 OST programs. Health Promotion Council participated in an enhanced cross-site evaluation with the national Robert Wood Johnson Foundation evaluator during the final year of funding to learn more about food and nutrition in the OST setting, and to share data and engage the OST food providers. A plate waste study measured the quantity and nutrition composition of meals served to youth compared to food not eaten. Staff interviews measured program adherence to the Healthy Living Guidelines, along with other facets of the food environment in 7 Philadelphia OST programs. Online surveys were sent to OST programs. Food providers (sponsors) were interviewed using Appreciative Inquiry methodology to gain insight into systems, goals, and common interests. Aggregated plate waste data from 7 observations showed an average of 42% of the food uneaten after meal/snack consumption, and high sodium content of the meals. Twenty-nine staff at OST programs completed the online survey, and 3 food sponsors were interviewed. Recommendations to improve the food included increasing variety, offering more salads, fruits and vegetables, and culturally appropriate foods. Food sponsor interviews showed a variety of meal production, distribution, service and training systems, and an interest in working together. The food sponsors met to review the data and prioritized common goals. They continue to work together to improve systems and meals for food service. A food sponsors work group formed and continues as a result of sharing enhanced cross-site data about food in OST settings. Food sponsors continue to work together to improve systems and nutritional offerings for Philadelphia OST programs.

  7. Performance Evaluation of Orbit Determination System during Initial Phase of INSAT-3 Mission

    Science.gov (United States)

    Subramanian, B.; Vighnesam, N. V.

    INSAT-3C is the second in the third generation of ISRO's INSAT series of satellites that was launched by ARIANE-SPACE on 23 January 2002 at 23 h 46 m 57 s (lift off time in U.T). The ARIANE-4 Flight Nr.147 took off from Kourou in French Guyana and injected the 2750-kg communications satellite in a geostationary transfer orbit of (571 X 35935) km with an inclination of 4.007 deg at 00 h 07 m 48 s U.T on 24 January 2002 (1252 s after lift off). The satellite was successfully guided into its intended geostationary position of 74 deg E longitude by 09 February 2002 after a series of four firings of its Liquid Apogee Motor (LAM) and four station acquisition (STAQ) maneuvers. Six distinct phases of the mission were categorized based on the orbit characteristics of the INSAT- 3C mission, namely, the pre-launch phase, the launch phase, transfer orbit phase, intermediate orbit phase, drift orbit phase and synchronous orbit phase. The orbit with a perigee height of 571 km at injection of the satellite, was gradually raised to higher orbits with perigee height increasing to 9346 km after Apogee Motor Firing #1 (AMF #1), 18335 km after AMF #2, 32448 km after AMF #3 and 35493 km after AMF #4. The North and South solar panels and the reflectors were deployed at this stage of the mission and the attitude of the satellite with respect to the three axes was stabilized. The Orbit Determination System (ODS) that was used in the initial phase of the mission played a crucial role in realizing the objectives of the mission. This system which consisted of Tracking Data Pre-Processing (TDPP) software, Ephemeris Generation (EPHGEN) software and the Orbit Determination (OD) software, performed rigorously and its results were used for planning the AMF and STAQ strategies with a greater degree of accuracy. This paper reports the results of evaluation of the performance of the apogee-motor firings employed to place the satellite in its intended position where it is collocated with INSAT-1D

  8. Evaluation of local stress for stress corrosion crack initiation by three-dimensional polycrystal model

    International Nuclear Information System (INIS)

    Kamaya, Masayuki; Kitamura, Takayuki

    2006-01-01

    In order to understand the initiation behavior of microstructurally small cracks in a stress corrosion cracking condition, it is important to know the tensile normal stress acting on the grain boundary (normal G.B. stress). The local stress in a polycrystalline body is greatly influenced by deformation constraint which is caused by anisotropic and/or inhomogeneous property of each grain. In present study, the local normal G.B. stress on bi- and tri-crystal bodies and a three-dimensional polycrystalline body consisting of 100 grains were evaluated by the finite element method under a remote uniform tensile stress condition. The polycrystalline body was generated by using a Monte Carlo procedure and random orientations were assigned to each grain. It was revealed that the local normal G.B. stress on the polycrystalline body is inhomogeneous under uniform applied stress. The stress tends to be large near the triple points due to the deformation constraint caused by adjacent grains, even though the grain boundary inclination to the load axis has large influence. It was also shown that particular high stress was not observed at corners of the polycrystalline body. (author)

  9. Evaluation of wireless sensor networks (WSNs) for remote wetland monitoring: design and initial results.

    Science.gov (United States)

    Watras, Carl J; Morrow, Michael; Morrison, Ken; Scannell, Sean; Yaziciaglu, Steve; Read, Jordan S; Hu, Yu-Hen; Hanson, Paul C; Kratz, Tim

    2014-02-01

    Here, we describe and evaluate two low-power wireless sensor networks (WSNs) designed to remotely monitor wetland hydrochemical dynamics over time scales ranging from minutes to decades. Each WSN (one student-built and one commercial) has multiple nodes to monitor water level, precipitation, evapotranspiration, temperature, and major solutes at user-defined time intervals. Both WSNs can be configured to report data in near real time via the internet. Based on deployments in two isolated wetlands, we report highly resolved water budgets, transient reversals of flow path, rates of transpiration from peatlands and the dynamics of chromophoric-dissolved organic matter and bulk ionic solutes (specific conductivity)-all on daily or subdaily time scales. Initial results indicate that direct precipitation and evapotranspiration dominate the hydrologic budget of both study wetlands, despite their relatively flat geomorphology and proximity to elevated uplands. Rates of transpiration from peatland sites were typically greater than evaporation from open waters but were more challenging to integrate spatially. Due to the high specific yield of peat, the hydrologic gradient between peatland and open water varied with precipitation events and intervening periods of dry out. The resultant flow path reversals implied that the flux of solutes across the riparian boundary varied over daily time scales. We conclude that WSNs can be deployed in remote wetland-dominated ecosystems at relatively low cost to assess the hydrochemical impacts of weather, climate, and other perturbations.

  10. Baby-Friendly Hospital Initiative: evaluation of the Ten Steps to Successful Breastfeeding

    Directory of Open Access Journals (Sweden)

    Soraia da Silva Lopes

    2013-12-01

    Full Text Available OBJECTIVE: To asses the performance of the Ten Steps to Successful Breastfeeding in an university hospital. METHODS: Descriptive and quantitative research, in which 103 people were interviewed in the outpatient prenatal clinic, in the maternity-ward and in the Neonatal Intensive Care Unit of a university hospital in Vitória, Southeast Brazil. The "Institutional Self-Evaluation Questionnaire" of the Baby Friendly Hospital Initiative was applied. Using this tool, the outcome was measured by the concordance index (CI proposed by the World Health Organization and by the United Nations Children's Fund. RESULTS: Although the hospital does not have a policy that addresses promotion, protection and support for breastfeeding, 93.3% of the mothers had contact with their babies immediately after birth (step 4, 83.3% of the professionals guided mothers how to breastfeed (step 5, 86.6% of the neonates did not receive any food or drink other than breast milk (step 6, 100% of babies were housed together with their mothers (step 7, 83.3% of the women were encouraged for breastfeeding on demand (step 8 and 100% of the infants did not use bottles or pacifiers (step 9. CONCLUSIONS: 60% of the steps were completed by the hospital. The greatest difficulty was to inform pregnant women about the importance and the management of breastfeeding (step 3. Therefore, visits to pregnant women are recommended, in order to prepare them for breastfeeding and to explain about the infants' healthy feeding habits.

  11. Extended Plate and Beam Wall System: Concept Investigation and Initial Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Wiehagen, J. [Partnership for Home Innovation, Upper Marlboro, MD (United States); Kochkin, V. [Partnership for Home Innovation, Upper Marlboro, MD (United States)

    2015-08-01

    A new and innovative High-R wall design, referred to as the Extended Plate & Beam (EP&B), is under development. The EP&B system uniquely integrates foam sheathing insulation with wall framing such that wood structural panels are installed exterior of the foam sheathing, enabling the use of standard practices for installation of drainage plane, windows and doors, claddings, cavity insulation, and the standard exterior foam sheathing installation approach prone to damage of the foam during transportation of prefabricated wall panels. As part of the ongoing work, the EP&B wall system concept has undergone structural verification testing and has been positively vetted by a group of industry stakeholders. Having passed these initial milestone markers, the advanced wall system design has been analyzed to assess cost implications relative to other advanced wall systems, undergone design assessment to develop construction details, and has been evaluated to develop representative prescriptive requirements for the building code. This report summarizes the assessment steps conducted to-date and provides details of the concept development.

  12. The Tribal Tobacco Education and Policy Initiative: Findings From a Collaborative, Participatory Evaluation.

    Science.gov (United States)

    Scott, Sheryl; D'Silva, Joanne; Hernandez, Carol; Villaluz, Nicole Toves; Martinez, Jaime; Matter, Chris

    2017-07-01

    While the reduction in the overall U.S. smoking prevalence has been declared one of the top 10 public health achievements of the past century, the growing disparity in smoking between American Indians and the general population is one of the biggest challenges of the 21st century. Minnesota in particular has very high smoking rates among American Indians (59%). Tribal Nations in Minnesota share a past of attempted cultural genocide and a present of restoring the strength of their cultural teachings, including the prominence of traditional tobacco as a sacred "first medicine." The Tribal Tobacco Education and Policy initiative works to address this complex and challenging context. This article describes results of a participatory evaluation from 2010 to 2013 in four Minnesota Tribal Nations-three Ojibwe and one Dakota. Tribal Tobacco Education and Policy coordinators used their cultural knowledge to develop community-level strategies, identifying appropriate strategies from best practices on tobacco advocacy, while drawing on the strengths of their own sovereignty and sacred tobacco traditions. Tribal coordinators generated support for policy change by conducting culturally relevant education, engaging tribal members, and nurturing relationships. This approach resulted in norm changes, practices toward restoring traditional tobacco, informal policies, and tribal resolutions to advance smoke-free policies.

  13. Evaluation of occupational factors on continuation of breastfeeding and formula initiation in employed mothers.

    Science.gov (United States)

    Ahmadi, Mahshid; Moosavi, Seyyed Mohammad

    2013-09-25

    During recent decades, women have been increasingly involved in social activities. Despite the fact that mothers prefer to breastfeed, their return to work is associated with a reduction in breastfeeding frequency and duration. The present study evaluates the impact of occupational factors on continuation of breastfeeding and formula initiation in employed mothers with infants aged 6-12 months in Bandar-Abbas, Iran in 2010. This is a descriptive-analytic study on employed mothers with infants aged 6-12 months referring to healthcare centers of Bandar-Abbas in 2010. Data were collected through a questionnaire dealing with work-related factors in mothers' workplace. Out of 212 mothers who responded, 52.38% used formula to feed their children, and 27.36% had discontinued breastfeeding. The rate of formula use was significantly higher in mothers who had less than 6 months of maternity leave, those who did not have a suitable nursery or place to milk themselves and preserve the milk in their workplace, those working more than 6 hours per day, and those who could not take a breastfeeding break. It is essential to identify and support breastfeeding employed women. The employers should provide facilities such as nurseries, a suitable physical space for milking, as well as the equipment necessary for milk preservation. Also, such mothers should be granted breastfeeding breaks to feed their child or milk their breasts.

  14. Initial counselling for cleft lip and palate: parents' evaluation, needs and expectations.

    Science.gov (United States)

    Kuttenberger, J; Ohmer, J N; Polska, E

    2010-03-01

    During the first counselling after the birth of a child with cleft lip and palate (CLP) information about the malformation should be delivered and a long-standing relationship between the cleft team and the affected family must be established. The present study was conducted to evaluate the parents' experiences, needs and expectations with this first consultation. A questionnaire was sent to 105 parents at the cleft clinic, which could be answered anonymously. It collected demographic data, data on the parents' pre-existing level of information and the parents' assessment of the counselling at the cleft centre. Seventy percent of the questionnaires were returned. In 16% the clefts were diagnosed prenatally, in 32% there were relatives with clefts. Seventy-one percent of the parents received detailed counselling, 89% of which occurred in the first week. The parents requested that information about surgery (80%), feeding the child (63%) and the aetiology of clefts (44%) should be given. The quality of the consultation was rated very good or good by 87% of families. This study confirms the importance of initial counselling for CLP. The exceptional psychological situation of the family has to be considered and a close collaboration between cleft centre and maternity hospitals is mandatory.

  15. Model-independent evaluation of recoils channeling impact on visible energy spectra in dark matter particles crystalline detectors

    International Nuclear Information System (INIS)

    Dyuldya, S.V.; Bratchenko, M.I.

    2012-01-01

    Proposed is a direct method of Dark Matter crystalline scintillation detectors calibration by means of an atomistic molecular dynamics modeling of their responses to ∼10 keV recoil atoms. Simulations show that the recoils channeling exists in NaI lattice with probabilities of ∼5 - 15 %. It does not affect the mean values of quenching factors but gives rise to high visible energy spectral tails absent in disordered detectors. As a result, the lattice ordering manifests the ∼100 % effect on NaI(Tl) visible energy spectra at 2-6 keV window

  16. The use of decision analysis to evaluate the economic effects of heat mount detectors in two dairy herds.

    Science.gov (United States)

    Williamson, N B

    1975-03-01

    This paper reports a decrease in the interval from calving to conception in two commercial dairy herds, associated with the use of KaMaR Heat Mount Detectors. An economic analysis of the results uses a neoclassical decision theory approach to demonstrate that the use of heat mount detectors is likely to be profitable, with an expected net return of $154.18 per 100 calvings. The analysis demonstrates the suitability of a decision-theoretic approach to the analysis of applied research, and illustrates some of the weaknesses of "Classical" statistical analysis in such circumstances.

  17. A framework for the monitoring and evaluation of international surgical initiatives in low- and middle-income countries.

    Science.gov (United States)

    Ibrahim, George M; Cadotte, David W; Bernstein, Mark

    2015-01-01

    An estimated two billion people worldwide lack adequate access to surgical care. To address this humanitarian emergency, an increasing number of international surgical partnerships are emerging between developed and low- and middle-income countries (LMICs). At present, there are no clear indicators that may be used to assess the effectiveness of such initiatives. We conducted an international qualitative study of 31 surgeons from developed and LMICs involved in international partnerships across a variety of subspecialties. Thematic analysis and grounded theory were applied in order to develop a practical framework that may be applied to monitor and evaluate global surgical initiatives. Several themes emerged from the study: (i) there is a large unmet need to establish and maintain prospective databases in LMICs to inform the monitoring and evaluation of international surgical partnerships; (ii) assessment of initiatives must occur longitudinally over the span of several years; (ii) the domains of assessment are contextual and encompass cultural, institutional and regional factors; and (iv) evaluation strategies should explore broader impact within the community and country. Based on thematic analysis within the domains of inputs, outputs and outcomes, a framework for the monitoring and evaluation of international surgical initiatives, the Framework for the Assessment of InteRNational Surgical Success (FAIRNeSS) is proposed. In response to the increasing number of surgical partnerships between developed and LMICs, we propose a framework to monitor and evaluate international surgical initiatives.

  18. Evaluation of Melt Behavior with initial Melt Velocity under SFR Severe Accidents

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Hyo; Bang, In Cheol [UNIST, Ulsan (Korea, Republic of); Jerng, Dong Wook [Chung-Ang Univ, Seoul (Korea, Republic of)

    2015-10-15

    In the current Korean sodium-cooled fast reactor (SFR) program, early dispersion of the molten metallic fuel within a subchannel is suggested as one of the inherent safety strategies for the initiating phase of hypothetical core disruptive accident (HCDA). The safety strategy provides negative reactivity driven by the melt dispersal, so it could reduce the possibility of the recriticality event under a severe triple or more fault scenario for SFR. Since the behavior of the melt dispersion is unpredictable, it depends on the accident condition, particularly core region. While the voided coolant channel region is usually developed in the inner core, the unvoided coolant channel region is formed in the outer core. It is important to confirm the fuel dispersion with the core region, but there are not sufficient existing studies for them. From the existing studies, the coolant vapor pressure is considered as one of driving force to move the melt towards outside of the core. There is a complexity of the phenomena during intermixing of the melt with the coolant after the horizontal melt injections. It is too difficult to understand the several combined mechanisms related to the melt dispersion and the fragmentation. Thus, it could be worthwhile to study the horizontal melt injections at lower temperature as a preliminary study in order to identify the melt dispersion phenomena. For this reason, it is required to clarify whether the coolant vapor pressure is the driving force of the melt dispersion with the core region. The specific conditions to be well dispersed for the molten metallic fuel were discussed in the experiments with the simulant materials. The each melt behavior was compared to evaluate the melt dispersion under the coolant void condition and the boiling condition. As the results, the following results are remarked: 1. The upward melt dispersion did not occur for a given melt and coolant temperature in the nonboiling range. Over current range of conditions

  19. Evaluation of Melt Behavior with initial Melt Velocity under SFR Severe Accidents

    International Nuclear Information System (INIS)

    Heo, Hyo; Bang, In Cheol; Jerng, Dong Wook

    2015-01-01

    In the current Korean sodium-cooled fast reactor (SFR) program, early dispersion of the molten metallic fuel within a subchannel is suggested as one of the inherent safety strategies for the initiating phase of hypothetical core disruptive accident (HCDA). The safety strategy provides negative reactivity driven by the melt dispersal, so it could reduce the possibility of the recriticality event under a severe triple or more fault scenario for SFR. Since the behavior of the melt dispersion is unpredictable, it depends on the accident condition, particularly core region. While the voided coolant channel region is usually developed in the inner core, the unvoided coolant channel region is formed in the outer core. It is important to confirm the fuel dispersion with the core region, but there are not sufficient existing studies for them. From the existing studies, the coolant vapor pressure is considered as one of driving force to move the melt towards outside of the core. There is a complexity of the phenomena during intermixing of the melt with the coolant after the horizontal melt injections. It is too difficult to understand the several combined mechanisms related to the melt dispersion and the fragmentation. Thus, it could be worthwhile to study the horizontal melt injections at lower temperature as a preliminary study in order to identify the melt dispersion phenomena. For this reason, it is required to clarify whether the coolant vapor pressure is the driving force of the melt dispersion with the core region. The specific conditions to be well dispersed for the molten metallic fuel were discussed in the experiments with the simulant materials. The each melt behavior was compared to evaluate the melt dispersion under the coolant void condition and the boiling condition. As the results, the following results are remarked: 1. The upward melt dispersion did not occur for a given melt and coolant temperature in the nonboiling range. Over current range of conditions

  20. The IMB proton decay detector

    International Nuclear Information System (INIS)

    Svoboda, R.C.; Gajewski, W.; Kropp, W.R.; Reines, F.; Schultz, J.; Smith, D.W.; Sobel, H.; Wuest, C.; Bionta, R.M.; Cortez, B.G.; Errede, S.; Foster, G.W.; Greenberg, J.; Park, H.S.; Shumard, E.; Sinclair, D.; Stone, J.L.; Sulak, L.R.; Velde, J.C. van der; Goldhaber, M.; Blewitt, G.; Lehmann, E.; LoSecco, J.M.; Bratton, C.B.; Learned, J.; Svoboda, R.; Jones, T.W.; Ramana Murthy, P.V.

    1983-01-01

    A description is given of the Irvine-Michigan-Brookhaven proton decay detector which is nearing completion in a salt mine in Cleveland, Ohio, U.S.A. The detector is a water Cerenkov one with a fiducial volume of 4,000 tons and a threshold of 24 MeV. Initial results indicate that the detector is working according to specification and has a high potential for deep underground cosmic ray applications. I will give a brief account of the IMB detector construction and operation and also its present status and possible cosmic ray applications. (orig.)

  1. GANIL beam profile detectors

    International Nuclear Information System (INIS)

    Tribouillard, C.

    1997-01-01

    In the design phase of GANIL which started in 1977, one of the priorities of the project management was equipping the beamlines with a fast and efficient system for visualizing the beam position, thus making possible adjustment of the beam transport lines optics and facilitating beam control. The implantation of some thirty detectors was foreseen in the initial design. The assembly of installed detectors (around 190) proves the advantages of these detectors for displaying all the beams extracted from GANIL: transfer and transport lines, beam extracted from SISSI, very high intensity beam, secondary ion beams from the production target of the LISE and SPEG spectrometers, different SPIRAL project lines. All of these detectors are based on standard characteristics: - standard flange diameter (DN 160) with a standard booster for all the sensors; - identical analog electronics for all the detectors, with networking; - unique display system. The new micro-channel plate non-interceptive detectors (beam profile and ion packet lengths) make possible in-line control of the beam quality and accelerator stability. (author)

  2. Lepton detector workshop summary

    International Nuclear Information System (INIS)

    Imlay, R.; Iwata, S.; Jacobs, S.

    1976-01-01

    A discussion is given of the initial detector design, focusing on the cost estimates and on the inner detector modules. With regard to inner modules, the rate problem was examined for the closest elements, and the question whether one should use argon or lead-liquid scintillator calorimeters was discussed. New designs which involved major modifications to the lepton detector are considered. The major motivations for alternative designs were twofold. One was that the original detector looked quite expensive, and a study of the tradeoff of money versus physics had not really been done yet. The second point was that, since the physics region to be explored was totally new ground, one would like to leave as many options open as possible and build a detector that was as flexible as possible. A scaled-down version of the original design, which was strongly favored by this study, appears to save an appreciable amount of money with a small decrease in the initial physics scope. The more modular designs seem quite attractive, but not enough time was spent to demonstrate feasibility

  3. Discrimination and quantification of implanted solar wind in Genesis collector shards using grazing incidence synchrotron x-ray techniques: New detector initial results

    International Nuclear Information System (INIS)

    Kitts, K.; Choi, Y.; Sutton, S.R.; Ghose, S.; Burnett, D.; Eng, P.

    2008-01-01

    Accurate knowledge of the composition of the Sun provides a baseline, which allows an understanding of how the solar system has evolved over time and how solar processes and solar wind mechanics behave. Unfortunately, the errors in photospheric abundances are too large for many planetary science problems and this hampers our understanding of these different processes. Analyses of solar wind implanted in meteorites or lunar soils have provided more precise data [e.g. 1 and references therein] but the extent to which alteration processes on these bodies complicate such information is only now being determined. Therefore, in order to obtain pristine solar wind samples, NASA developed and launched the Genesis Discovery Mission. Unfortunately, the probe crash-landed shattering the 300 collector plates into 15,000+ pieces complicating the analysis and necessitating the development of new analytical techniques and equipment. Thus, shards from the Genesis collector array and their appropriate flight spares are currently being characterized via grazing-incidence synchrotron x-ray techniques at the Advanced Photon Source at Argonne National Laboratory. The goals are (1) determine solar wind fluences of the elements Ca-Ge by grazing-incidence angle-resolved x-ray fluorescence (XRF) and x-ray reflectivity, (2) improve data reduction via the development of XRF spectral deconvolution routines and develop modeling algorithms for reflectivity and fluorescence yield analysis in order to determine element specific depth profiles from which absolute concentration may be extracted and (3) designing and developing a new multi-element silicon multi-channel (SMCD) detector system. These improvements will increase our sensitivity by a factor of three or more, reduce measurement time at a given sensitivity to one-eighth and the minimum detection limit would be reduced by a factor of 3 to ∼3 x 10 8 atoms/cm 2 .

  4. Evaluation of initiation behavior of stress corrosion cracking for type 316L stainless steel in high temperature water. Behavior of crack initiation and effects of distribution of plastic strain on crack initiation

    International Nuclear Information System (INIS)

    Miura, Yasufumi; Miyahara, Yuichi; Kako, Kenji; Sato, Masaru

    2011-01-01

    It is known that the initiation of stress corrosion cracking (SCC) in components such as the reactor core shroud and primary loop re-circulation piping made of L-grade stainless steel is affected by the properties of surface work hardened layer. Therefore, it is important to clarify the effect of the hardened layer on SCC initiation behavior. In this study, creviced bent beam (CBB) test using specimens made of Type 316L stainless steel with controlled distribution of surface work hardened layer was conducted in a simulated BWR environment in order to evaluate the effect of the controlled layer on SCC initiation behavior. The results obtained are as follows; (1) Micro intergranular SCC of low carbon stainless steel was initiated in 50 hours. (2) In this SCC test, it was found that only micro cracks whose depths were smaller than 50 μm were observed until 250 hours and cracks whose depths were larger than 50 μm were observed after 500 hours. (3) SCC was initiated preferentially on the region with high plastic strain gradient in the specimen with controlled distribution of work hardened layer. (author)

  5. Cryogenic detectors

    International Nuclear Information System (INIS)

    Zehnder, A.

    1987-01-01

    Presently the development of new large scale detector systems, used in very high energy physics experiments, is very active. In the low energy range, the introduction of charge coupled devices allows improved spacial and energy resolution. In the keV region, high resolution can only be achieved via the well established diffraction spectrometers with the well-known disadvantage of a small throughput. There exist no efficient detectors for non-ionizing radiation such as coherent nuclear scattering of weakly interacting particles. The development of high resolution solid state detectors in the keV-region with the possibility of nuclear recoil detection is therefore highly desired. Such detectors applied in astro and particle physics would thus allow one to obtain new information not achievable otherwise. Three types of cryogenic detectors exist: Calorimeters/Bolometers. This type is sensitive to the produced excess phonons and measures the deposited energy by detecting the heat pulses. Excess charge carriers should be used to produce phonons. Tunneling junctions. This type is sensitive to excess charge produced by the Cooper pair breakup. Excess phonons should be used to break up Cooper pairs. Superheated superconducting granules (SSG). An SSG detector consists of granules, the metastability of which is disturbed by radiation. The Meissner effect then causes a change in the field distribution of the applied external field, which can be detected. The present paper discusses the basic principle of calorimetric and tunneling junction detectors and some of their applications. 26 refs., 7 figs., 1 tab

  6. A simplified ingestion procedure for esophageal capsule endoscopy: initial evaluation in healthy volunteers.

    Science.gov (United States)

    Gralnek, I M; Rabinovitz, R; Afik, D; Eliakim, R

    2006-09-01

    Initial studies on esophageal capsule endoscopy (PillCam ESO) reported excellent sensitivity and specificity, but these were followed by mixed results in several subsequent studies, probably due to deviations from the recommended ingestion protocol and the inconvenience of capsule ingestion in the supine position. The aim of this study was therefore to test a simplified ingestion procedure (SIP) for PillCam ESO. Using a cross-over study design, the SIP was prospectively compared with the original ingestion procedure for PillCam ESO in 24 healthy volunteers (15 men, nine women; mean age 44, range 27 - 70) and evaluated for: bubbles/saliva interference at the Z-line, Z-line circumferential visualization (quadrants), and convenience and ease of the ingestion procedure. All Rapid 4 videos were reviewed in a randomized manner and read by an experienced PillCam ESO reader blinded to the ingestion procedure used. It was found that the SIP significantly improved visualization in comparison with the original ingestion procedure, with less interference due to bubbles/saliva observed at the gastroesophageal junction ( P = 0.002) and improved visualization of the Z-line ( P = 0.025). Although the esophageal transit time was significantly faster with the SIP (3 : 45 min vs. 0 : 38 min; P = 0.0001), there were no differences in the number of Z-line frames/images captured. This new, simplified ingestion procedure for PillCam ESO provides significantly improved visualization of the Z-line in healthy volunteers. The overall test characteristics of PillCam ESO using SIP should be tested in patients with esophageal disease.

  7. Evaluation of chondrocalcinosis and associated knee joint degeneration using MR imaging: Data from the osteoarthritis initiative

    Energy Technology Data Exchange (ETDEWEB)

    Gersing, Alexandra S.; Schwaiger, Benedikt J.; Heilmeier, Ursula; Joseph, Gabby B.; Facchetti, Luca; Kretzschmar, Martin; Steinbach, Lynne S.; Link, Thomas M. [University of California, San Francisco, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States); Lynch, John A.; McCulloch, Charles E.; Nevitt, Michael C. [University of California, San Francisco, Department of Epidemiology and Biostatistics, San Francisco, CA (United States)

    2017-06-15

    To evaluate the ability of different MRI sequences to detect chondrocalcinosis within knee cartilage and menisci, and to analyze the association with joint degeneration. Subjects with radiographic knee chondrocalcinosis (n = 90, age 67.7 ± 7.3 years, 50 women) were selected from the Osteoarthritis Initiative and matched to controls without radiographic chondrocalcinosis (n = 90). Visualization of calcium-containing crystals (CaC) was compared between 3D T1-weighted gradient-echo (T1GE), 3D dual echo steady-state (DESS), 2D intermediate-weighted (IW), and proton density (PD)-weighted fast spin-echo (FSE) sequences obtained with 3T MRI and correlated with a semiquantitative CaC score obtained from radiographs. Structural abnormalities were assessed using Whole-Organ MRI Score (WORMS) and logistic regression models were used to compare cartilage compartments with and without CaC. Correlations between CaC counts of MRI sequences and degree of radiographic calcifications were highest for GE (r{sub T1GE} = 0.73, P < 0.001; r{sub DESS} = 0.68, P < 0.001) compared to other sequences (P > 0.05). Meniscus WORMS was significantly higher in subjects with chondrocalcinosis compared to controls (P = 0.005). Cartilage defects were significantly more frequent in compartments with CaC than without (patella: P = 0.006; lateral tibia: P < 0.001; lateral femur condyle: P = 0.017). Gradient-echo sequences were most useful for the detection of chondrocalcinosis and presence of CaC was associated with higher prevalence of cartilage and meniscal damage. (orig.)

  8. The Use of the Data Assimilation Research Testbed for Initializing and Evaluating IPCC Decadal Forecasts

    Science.gov (United States)

    Raeder, K.; Anderson, J. L.; Lauritzen, P. H.; Hoar, T. J.; Collins, N.

    2010-12-01

    DART (www.image.ucar.edu/DAReS/DART) is a general purpose, freely available, ensemble Kalman filter, data assimilation system, which is being used to generate state-of-the-art, partially coupled, ocean-atmosphere re-analyses in support of the decadal predictions planned for the next IPCC report. The resulting gridded product is directly comparable to the state variables output by POP and CAM (oceanic and atmospheric components of NCAR's Community Earth System Model climate model) because those are the assimilating models. Other models could also benefit from comparison against these reanalyses, since the ocean analyses are at the leading edge of ocean state estimation, and the atmospheric analyses are competitive with operational centers'. Such comparisons can reveal model biases and predictability characteristics, and do so in a quantitative way, since the ensemble nature of the analyses provides an objective estimate of the analysis error. The analyses will also be used as initial conditions for the decadal forecasts because they are the most realistic available. The generation of such analyses has revealed errors in model formulation for several versions of the finite volume core CAM, which has led to model improvements in each case. New models can be incorporated into DART in a matter of weeks, allowing them to be compared directly against available observations. The observations currently used in the assimilations include, for the ocean; temperature and salinity from the World Ocean Database (floats, drifters, moorings, autonomous pinipeds, and others), and for the atmosphere; temperature and winds from radiosondes, satellite drift winds, ACARS and aircraft. Observations of ocean currents and atmospheric moisture and pressure are also available. Global Positioning System profiles of atmospheric temperature and moisture are available for recent years. All that is required to add new observations to the suite is the forward operator, which generates an estimate

  9. Evaluation of Chondrocalcinosis and Associated Knee Joint Degeneration Using MR Imaging: Data from the Osteoarthritis Initiative.

    Science.gov (United States)

    Gersing, Alexandra S; Schwaiger, Benedikt J; Heilmeier, Ursula; Joseph, Gabby B; Facchetti, Luca; Kretzschmar, Martin; Lynch, John A; McCulloch, Charles E; Nevitt, Michael C; Steinbach, Lynne S; Link, Thomas M

    2017-06-01

    To evaluate the ability of different MRI sequences to detect chondrocalcinosis within knee cartilage and menisci, and to analyze the association with joint degeneration. Subjects with radiographic knee chondrocalcinosis (n = 90, age 67.7 ± 7.3 years, 50 women) were selected from the Osteoarthritis Initiative and matched to controls without radiographic chondrocalcinosis (n = 90). Visualization of calcium-containing crystals (CaC) was compared between 3D T1-weighted gradient-echo (T1GE), 3D dual echo steady-state (DESS), 2D intermediate-weighted (IW), and proton density (PD)-weighted fast spin-echo (FSE) sequences obtained with 3T MRI and correlated with a semiquantitative CaC score obtained from radiographs. Structural abnormalities were assessed using Whole-Organ MRI Score (WORMS) and logistic regression models were used to compare cartilage compartments with and without CaC. Correlations between CaC counts of MRI sequences and degree of radiographic calcifications were highest for GE (r T1GE  = 0.73, P  0.05). Meniscus WORMS was significantly higher in subjects with chondrocalcinosis compared to controls (P = 0.005). Cartilage defects were significantly more frequent in compartments with CaC than without (patella: P = 0.006; lateral tibia: P < 0.001; lateral femur condyle: P = 0.017). Gradient-echo sequences were most useful for the detection of chondrocalcinosis and presence of CaC was associated with higher prevalence of cartilage and meniscal damage. • Magnetic resonance imaging is useful for assessing burden of calcium-containing crystals (CaC). • Gradient-echo sequences are superior to fast spin echo sequences for CaC imaging. • Presence of CaC is associated with meniscus and cartilage degradation.

  10. Initial evaluation and referral guidelines for management of pelvic/ovarian masses.

    Science.gov (United States)

    Le, Tien; Giede, Christopher; Salem, Shia; Lefebvre, Guylaine; Rosen, Barry; Bentley, James; Kupets, Rachel; Power, Patti; Renaud, Marie-Claude; Bryson, Peter; Davis, Donald B; Lau, Susie; Lotocki, Robert; Senikas, Vyta; Morin, Lucie; Bly, Stephen; Butt, Kimberly; Cargill, Yvonne M; Denis, Nanette; Gagnon, Robert; Hietala-Coyle, Marja Anne; Lim, Kenneth Ian; Ouellet, Annie; Raciot, Maria-Hélène

    2009-07-01

    To optimize the management of adnexal masses and to assist primary care physicians and gynaecologists determine which patients presenting with an ovarian mass with a significant risk of malignancy should be considered for gynaecologic oncology referral and management. Laparoscopic evaluation, comprehensive surgical staging for early ovarian cancer, or tumour debulking for advanced stage ovarian cancer. To optimize conservative versus operative management of women with possible ovarian malignancy and to optimize the involvement of gynaecologic oncologists in planning and delivery of treatment. Published literature was retrieved through searches of PubMed or MEDLINE, CINAHL, and the Cochrane Library, using appropriate controlled vocabulary and key words. Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. Grey (unpublished) literature was identified by searching the web sites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. 1. Primary care physicians and gynaecologists should always consider the possibility of an underlying ovarian cancer in patients in any age group who present with an adnexal or ovarian mass. (II-2B) 2. Appropriate workup of a perimenopausal or postmenopausal woman presenting with an adnexal mass should include evaluation of symptoms and signs suggestive of malignancy, such as persistent pelvic/abdominal pain, urinary urgency/frequency, increased abdominal size/bloating, and difficulty eating. In addition, CA125 measurement should be considered. (II-2B) 3. Transvaginal or transabdominal ultrasound examination is recommended as part of the initial workup of a complex adnexal/ovarian mass. (II-2B) 4. Ultrasound reports should be standardized to include size and unilateral/bilateral location of the adnexal mass and

  11. Detectors - Electronics

    International Nuclear Information System (INIS)

    Bregeault, J.; Gabriel, J.L.; Hierle, G.; Lebotlan, P.; Leconte, A.; Lelandais, J.; Mosrin, P.; Munsch, P.; Saur, H.; Tillier, J.

    1998-01-01

    The reports presents the main results obtained in the fields of radiation detectors and associated electronics. In the domain of X-ray gas detectors for the keV range efforts were undertaken to rise the detector efficiency. Multiple gap parallel plate chambers of different types as well as different types of X → e - converters were tested to improve the efficiency (values of 2.4% at 60 KeV were reached). In the field of scintillators a study of new crystals has been carried out (among which Lutetium orthosilicate). CdTe diode strips for obtaining X-ray imaging were studied. The complete study of a linear array of 8 CdTe pixels has been performed and certified. The results are encouraging and point to this method as a satisfying solution. Also, a large dimension programmable chamber was used to study the influence of temperature on the inorganic scintillators in an interval from -40 deg. C to +150 deg. C. Temperature effects on other detectors and electronic circuits were also investigated. In the report mentioned is also the work carried out for the realization of the DEMON neutron multidetector. For neutron halo experiments different large area Si detectors associated with solid and gas position detectors were realized. In the frame of a contract with COGEMA a systematic study of Li doped glasses was undertaken aiming at replacing with a neutron probe the 3 He counters presently utilized in pollution monitoring. An industrial prototype has been realised. Other studies were related to integrated analog chains, materials for Cherenkov detectors, scintillation probes for experiments on fundamental processes, gas position sensitive detectors, etc. In the field of associated electronics there are mentioned the works related to the multidetector INDRA, data acquisition, software gamma spectrometry, automatic gas pressure regulation in detectors, etc

  12. Evaluation of a wavelet-based compression algorithm applied to the silicon drift detectors data of the ALICE experiment at CERN

    International Nuclear Information System (INIS)

    Falchieri, Davide; Gandolfi, Enzo; Masotti, Matteo

    2004-01-01

    This paper evaluates the performances of a wavelet-based compression algorithm applied to the data produced by the silicon drift detectors of the ALICE experiment at CERN. This compression algorithm is a general purpose lossy technique, in other words, its application could prove useful even on a wide range of other data reduction's problems. In particular the design targets relevant for our wavelet-based compression algorithm are the following ones: a high-compression coefficient, a reconstruction error as small as possible and a very limited execution time. Interestingly, the results obtained are quite close to the ones achieved by the algorithm implemented in the first prototype of the chip CARLOS, the chip that will be used in the silicon drift detectors readout chain

  13. Evaluation of delivered monitor unit accuracy of gated step-and-shoot IMRT using a two-dimensional detector array

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Kwang-Ho; Kang, Sei-Kwon; Lee, MeYeon; Kim, Su SSan; Park, SoAh; Hwang, Tae-Jin; Kim, Kyoung Ju; Oh, Do Hoon; Bae, Hoonsik; Suh, Tae-Suk [Department of Radiation Oncology, Hallym University College of Medicine, Seoul, 431070 (Korea, Republic of) and Department of Biomedical Engineering, College of Medicine, Catholic University of Korea, Seoul 137701 (Korea, Republic of); Department of Radiation Oncology, Hallym University College of Medicine, Seoul 431070 (Korea, Republic of); Department of Biomedical Engineering, College of Medicine, Catholic University of Korea, Seoul 137701 (Korea, Republic of)

    2010-03-15

    Purpose: To overcome the problem of organ motion in intensity-modulated radiation therapy (IMRT), gated IMRT is often used for the treatment of lung cancer. In this study, the authors investigated the accuracy of the delivered monitor units (MUs) from each segment during gated IMRT using a two-dimensional detector array for user-specific verification purpose. Methods: The authors planned a 6 MV photon, seven-port step-and-shoot lung IMRT delivery. The respiration signals for gated IMRT delivery were obtained from the one-dimensional moving phantom using the real-time position management (RPM) system (Varian Medical Systems, Palo Alto, CA). The beams were delivered using a Clinac iX (Varian Medical Systems, Palo Alto, CA) with the Millennium 120 MLC. The MatriXX (IBA Dosimetry GmbH, Germany) was validated through consistency and reproducibility tests as well as comparison with measurements from a Farmer-type ion chamber. The authors delivered beams with varying dose rates and duty cycles and analyzed the MatriXX data to evaluate MU delivery accuracy. Results: There was quite good agreement between the planned segment MUs and the MUs computed from the MatriXX within {+-}2% error. The beam-on times computed from the MatriXX data were almost identical for all cases, and they matched well with the RPM beam-on and beam-off signals. A slight difference was observed between them, but it was less than 40 ms. The gated IMRT delivery demonstrated an MU delivery accuracy that was equivalent to ungated IMRT, and the delivered MUs with a gating signal agreed with the planned MUs within {+-}0.5 MU regardless of dose rate and duty cycle. Conclusions: The authors can conclude that gated IMRT is able to deliver an accurate dose to a patient during a procedure. The authors believe that the methodology and results can be transferred to other vendors' devices, particularly those that do not provide MLC log data for a verification purpose.

  14. Focusing on the Whole Student: An Evaluation of Massachusetts's Wraparound Zone Initiative

    Science.gov (United States)

    Gandhi, Allison Gruner; Slama, Rachel; Park, So Jung; Russo, Patrick; Winner, Kendra; Bzura, Robin; Jones, Wehmah; Williamson, Sandra

    2018-01-01

    We used a comparative interrupted time series design to examine the impact of the Massachusetts' Wraparound Zone Initiative on student achievement, attendance, retention, and suspension. This initiative was designed to create coordinated district systems that allow schools to proactively and systematically address students' nonacademic needs. The…

  15. The Early College High School Initiative: An Overview of Five Evaluation Years

    Science.gov (United States)

    Berger, Andrea; Adelman, Nancy; Cole, Susan

    2010-01-01

    In 2002, the Bill & Melinda Gates Foundation started the Early College High School Initiative (ECHSI). Through this initiative, more than 200 Early College Schools (ECSs) opened by fall 2009. All of the schools aim to provide underserved students access to college classes while in high school. This article will provide an overview of the first 6…

  16. Development and Psychometric Evaluation of the Personal Growth Initiative Scale-II

    Science.gov (United States)

    Robitschek, Christine; Ashton, Matthew W.; Spering, Cynthia C.; Geiger, Nathaniel; Byers, Danielle; Schotts, G. Christian; Thoen, Megan A.

    2012-01-01

    The original Personal Growth Initiative Scale (PGIS; Robitschek, 1998) was unidimensional, despite theory identifying multiple components (e.g., cognition and behavior) of personal growth initiative (PGI). The present research developed a multidimensional measure of the complex process of PGI, while retaining the brief and psychometrically sound…

  17. Hydrogen detector

    International Nuclear Information System (INIS)

    Kumagaya, Hiromichi; Yoshida, Kazuo; Sanada, Kazuo; Chigira, Sadao.

    1994-01-01

    The present invention concerns a hydrogen detector for detecting water-sodium reaction. The hydrogen detector comprises a sensor portion having coiled optical fibers and detects hydrogen on the basis of the increase of light transmission loss upon hydrogen absorption. In the hydrogen detector, optical fibers are wound around and welded to the outer circumference of a quartz rod, as well as the thickness of the clad layer of the optical fiber is reduced by etching. With such procedures, size of the hydrogen detecting sensor portion can be decreased easily. Further, since it can be used at high temperature, diffusion rate is improved to shorten the detection time. (N.H.)

  18. Evaluation of the effect of initial texture on the development of deformation texture

    DEFF Research Database (Denmark)

    Leffers, Torben; Juul Jensen, Dorte

    1986-01-01

    The authors describe a computer procedure which allows them to introduce experimental initial textures as starting conditions for texture simulation (instead of a theoretical random texture). They apply the procedure on two batches of copper with weak initial textures and on fine-grained and coarse......-grained aluminium with moderately strong initial textures. In copper the initial texture turns out to be too weak to have any significant effect. In aluminium the initial texture has a very significant effect on the simulated textures-similar to the effect it has on the experimental textures. However......, there are differences between the simulated and the experimental aluminium textures that can only be explained as a grain-size effect. Possible future applications of the procedure are discussed...

  19. The ATLAS Inner Detector commissioning and calibration

    NARCIS (Netherlands)

    Aad, G.; et al., [Unknown; Bentvelsen, S.; Colijn, A.P.; de Jong, P.; Doxiadis, A.; Garitaonandia, H.; Gosselink, M.; Kayl, M.S.; Koffeman, E.; Lee, H.; Mechnich, J.; Mussche, I.; Ottersbach, J.P.; Rijpstra, M.; Ruckstuhl, N.; Tsiakiris, M.; van der Kraaij, E.; van der Poel, E.; van Kesteren, Z.; van Vulpen, I.; Vermeulen, J.C.; Vreeswijk, M.

    2010-01-01

    The ATLAS Inner Detector is a composite tracking system consisting of silicon pixels, silicon strips and straw tubes in a 2 T magnetic field. Its installation was completed in August 2008 and the detector took part in data-taking with single LHC beams and cosmic rays. The initial detector operation,

  20. DUMAND detector

    CERN Multimedia

    This object is one of the 256 other detectors of the DUMAND (Deep Underwater Muon And Neutrino Detection) experiment. The goal of the experiment was the construction of the first deep ocean high energy neutrino detector, to be placed at 4800 m depth in the Pacific Ocean off Keahole Point on the Big Island of Hawaii. A few years ago, a European conference with Cosmic experiments was organized at CERN as they were projects like DUMAND in Hawaii. Along with the conference, a temporary exhibition was organised as well. It was a collaboration of institutions from Germany, Japan, Switzerland and the U.S.A. CERN had borrowed equipment and objects from different institutes around the world, including this detector of the DUMAND experiment. Most of the equipment were sent back to the institutes, however this detector sphere was offered to a CERN member of the personnel.

  1. Detector applications

    International Nuclear Information System (INIS)

    Pehl, R.H.

    1977-10-01

    Semiconductor detectors are now applied to a very wide range of problems. The combination of relatively low cost, excellent energy resolution, and simultaneous broad energy-spectrum analysis is uniquely suited to many applications in both basic and applied physics. Alternative techniques, such as magnetic spectrometers for charged-particle spectroscopy, while offering better energy resolution, are bulky, expensive, and usually far more difficult to use. Furthermore, they do not directly provide the broad energy-spectrum measurements easily accomplished using semiconductor detectors. Scintillation detectors, which are approximately equivalent to semiconductor detectors in convenience and cost, exhibit 10 to 100 times worse energy resolution. However, their high efficiency and large potential size recommend their use in some measurements

  2. Preliminary safety evaluation, based on initial site investigation data. Planning document

    International Nuclear Information System (INIS)

    Hedin, Allan

    2002-12-01

    This report is a planning document for the preliminary safety evaluations (PSE) to be carried out at the end of the initial stage of SKBs ongoing site investigations for a deep repository for spent nuclear fuel. The main purposes of the evaluations are to determine whether earlier judgements of the suitability of the candidate area for a deep repository with respect to long-term safety holds up in the light of borehole data and to provide feed-back to continued site investigations and site specific repository design. The preliminary safety evaluations will be carried out by a safety assessment group, based on a site model, being part of a site description, provided by a site modelling group and a repository layout within that model suggested by a repository engineering group. The site model contains the geometric features of the site as well as properties of the host rock. Several alternative interpretations of the site data will likely be suggested. Also the biosphere is included in the site model. A first task for the PSE will be to compare the rock properties described in the site model to previously established criteria for a suitable host rock. This report gives an example of such a comparison. In order to provide more detailed feedback, a number of thermal, hydrological, mechanical and chemical analyses of the site will also be included in the evaluation. The selection of analyses is derived from the set of geosphere and biosphere analyses preliminarily planned for the comprehensive safety assessment named SR-SITE, which will be based on a complete site investigation. The selection is dictated primarily by the expected feedback to continued site investigations and by the availability of data after the PSE. The repository engineering group will consider several safety related factors in suggesting a repository layout: Thermal calculations will be made to determine a minimum distance between canisters avoiding canister surface temperatures above 100 deg C

  3. Smoke detectors

    International Nuclear Information System (INIS)

    Bryant, J.; Howes, J.H.; Smout, D.W.S.

    1979-01-01

    A smoke detector is described which provides a smoke sensing detector and an indicating device and in which a radioactive substance is used in conjunction with two ionisation chambers. The system includes an outer electrode, a collector electrode and an inner electrode which is made of or supports the radioactive substance which, in this case, is 241 Am. The invention takes advantage of the fact that smoke particles can be allowed to enter freely the inner ionisation chamber. (U.K.)

  4. Radiation detector

    International Nuclear Information System (INIS)

    Gillies, W.

    1980-01-01

    The radiation detector for measuring e.g. a neutron flux consists of a central emitter, an insulating shell arranged around it, and a tube-shaped collector enclosing both. The emitter itself is composed of a great number of stranded, spiral wires of small diameter giving a defined flexibility to the detector. For emitter material Pt, Rh, V, Co, Ce, Os or Ta may be used. (DG) [de

  5. Split detector

    International Nuclear Information System (INIS)

    Cederstrand, C.N.; Chism, H.R.

    1982-01-01

    A gas analyzer is disclosed which provides a dual channel capability for the simultaneous determination of the presence and concentration of two gases in a stream of sample gas and which has a single infrared source, a single sample cell, two infrared bandpass filters, and two infrared detectors. A separator between the filters and detectors prevents interchange of radiation between the filters. The separator is positioned by fitting it in a slot

  6. Development, implementation and evaluation of a peer review of teaching (PRoT) initiative in nursing education.

    Science.gov (United States)

    Mager, Diana R; Kazer, Meredith W; Conelius, Jaclyn; Shea, Joyce; Lippman, Doris T; Torosyan, Roben; Nantz, Kathryn

    2014-06-03

    For many years, an area of research in higher education has been emerging around the development and implementation of fair and effective peer evaluation programs. Recently, a new body of knowledge has developed regarding the development and implementation of fair and effective peer evaluation programs resulting in formative and summative evaluations. The purpose of this article is to describe the development, implementation, and evaluation of a peer review of teaching (PRoT) program for nursing faculty, initiated at one small comprehensive university in the northeastern United States. Pairs of nursing faculty evaluated each other's teaching, syllabi, and course materials after collaborating in a pre-evaluation conference to discuss goals of the classroom visit. Qualitative data gathered in post project focus groups revealed that faculty found their modified PRoT process to be a mutually beneficial experience that was more useful, flexible and collegial, and less stressful than their previous evaluation process.

  7. Radical Initiated Hydrosilylation on Silicon Nanocrystal Surfaces: An Evaluation of Functional Group Tolerance and Mechanistic Study.

    Science.gov (United States)

    Yang, Zhenyu; Gonzalez, Christina M; Purkait, Tapas K; Iqbal, Muhammad; Meldrum, Al; Veinot, Jonathan G C

    2015-09-29

    Hydrosilylation is among the most common methods used for modifying silicon surface chemistry. It provides a wide range of surface functionalities and effective passivation of surface sites. Herein, we report a systematic study of radical initiated hydrosilylation of silicon nanocrystal (SiNC) surfaces using two common radical initiators (i.e., 2,2'-azobis(2-methylpropionitrile) and benzoyl peroxide). Compared to other widely applied hydrosilylation methods (e.g., thermal, photochemical, and catalytic), the radical initiator based approach is particle size independent, requires comparatively low reaction temperatures, and yields monolayer surface passivation after short reaction times. The effects of differing functional groups (i.e., alkene, alkyne, carboxylic acid, and ester) on the radical initiated hydrosilylation are also explored. The results indicate functionalization occurs and results in the formation of monolayer passivated surfaces.

  8. Evaluations of environmental effect on micro crack initiation and propagation by surface observations of fatigue specimens

    International Nuclear Information System (INIS)

    Fujikawa, Ryosuke; Abe, Shigeki; Nakamura, Takao; Kamaya, Masayuki

    2014-01-01

    Fatigue life of nuclear facilities tends to be decreased by the influence of reactor coolant, which is called environmental effect. The effect accelerates crack growth rate but the influence for crack initiation is not clarified. This study intends to discuss the environmental effect in crack initiation. The crack length and the number of cracks are measured from the investigation of fatigue test specimens in reactor coolant and air. The behavior of crack initiation is revealed from the measurement of number of cracks, crack sizes and fatigue life. From this study, environmental effect of reactor coolant is considered to influence crack initiation and increase the number of micro crack. It is also estimated that the coalescence of cracks influences the acceleration of crack growth. (author)

  9. Evaluating the impact of the Extractive Industries Transparency Initiative (EITI) on corruption in Zambia

    NARCIS (Netherlands)

    P. Fenton Villar (Paul); E. Papyrakis (Elissaios)

    2016-01-01

    textabstractThe Extractive Industries Transparency Initiative (EITI) is internationally recognised as a leading anti-corruption scheme, which promotes transparency, accountability and good governance of public oil, gas, and mining revenues. This article provides the first rigorous quantitative

  10. [A framework for evaluating ethical issues of public health initiatives: practical aspects and theoretical implications].

    Science.gov (United States)

    Petrini, Carlo

    2015-01-01

    The "Framework for the Ethical Conduct of Public Health Initiatives", developed by Public Health Ontario, is a practical guide for assessing the ethical implications of evidence-generating public health initiatives, whether research or non-research activities, involving people, their biological materials or their personal information. The Framework is useful not only to those responsible for determining the ethical acceptability of an initiative, but also to investigators planning new public health initiatives. It is informed by a theoretical approach that draws on widely shared bioethical principles. Two considerations emerge from both the theoretical framework and its practical application: the line between practice and research is often blurred; public health ethics and biomedical research ethics are based on the same common heritage of values.

  11. Initial psychometric evaluation of the Moral Injury Questionnaire--Military version.

    Science.gov (United States)

    Currier, Joseph M; Holland, Jason M; Drescher, Kent; Foy, David

    2015-01-01

    Moral injury is an emerging construct related to negative consequences associated with war-zone stressors that transgress military veterans' deeply held values/beliefs. Given the newness of the construct, there is a need for instrumentation that might assess morally injurious experiences (MIEs) in this population. Drawing on a community sample of 131 Iraq and/or Afghanistan Veterans and clinical sample of 82 returning Veterans, we conducted an initial psychometric evaluation of the newly developed Moral Injury Questionnaire-Military version (MIQ-M)-a 20-item self-report measure for assessing MIEs. Possibly due to low rates of reporting, an item assessing sexual trauma did not yield favourable psychometric properties and was excluded from analyses. Veterans in the clinical sample endorsed significantly higher scores across MIQ-M items. Factor analytic results for the final 19 items supported a unidimensional structure, and convergent validity analyses revealed that higher scores (indicative of more MIEs) were correlated with greater general combat exposure, impairments in work/social functioning, posttraumatic stress and depression in the community sample. In addition, when controlling for demographics, deployment-related factors and exposure to life threat stressors associated with combat, tests of incremental validity indicated that MIQ-M scores were also uniquely linked with suicide risk and other mental health outcomes. These findings provide preliminary evidence for the validity of the MIQ-M and support the applicability of this measure for further research and clinical work with Veterans. Military service can confront service members with experiences that undermine their core sense of humanity and violate global values and beliefs. These types of experiences increase the risk for posttraumatic maladjustment in this population, even when accounting for rates of exposure to life threat traumas. Moral injury is an emerging construct to more fully capture the many

  12. Diagnostic Accuracy of Ultrasonography and Radiography in Initial Evaluation of Chest Trauma Patients.

    Science.gov (United States)

    Vafaei, Ali; Hatamabadi, Hamid Reza; Heidary, Kamran; Alimohammadi, Hosein; Tarbiyat, Mohammad

    2016-01-01

    Application of chest radiography for all multiple trauma patients is associated with a significant increase in total costs, exposure to radiation, and overcrowding of the emergency department. Ultrasound has been introduced as an alternative diagnostic tool in this regard. The aim of the present study is to compare the diagnostic accuracy of chest ultrasonography and radiography in detection of traumatic intrathoracic injuries. In the present prospective cross-sectional study, patients with traumatic intrathoracic injuries, who were referred to the emergency department from December 2013 to December 2014, were assessed. The patients underwent bedside ultrasound, radiographic and computed tomography (CT) scan examinations based on ATLS recommendations. Screening performance characteristics of ultrasonography and radiography were compared using SPSS 21.0. Chest CT scan was considered as gold standard. 152 chest trauma patients with a mean age of 31.4 ± 13.8 years (range: 4 ‒ 67), were enrolled (77.6% male). Chest CT scan showed pulmonary contusion in 48 (31.6%) patients, hemothorax in 29 (19.1%), and pneumothorax in 55 (36.2%) cases. Area under the ROC curve of ultrasonography in detection of pneumothorax, hemothorax, and pulmonary contusion were 0.91 (95% CI: 0.86‒0.96), 0.86 (95% CI: 0.78‒0.94), and 0.80 (95% CI: 0.736‒0.88), respectively. Area under the ROC curve of radiography was 0.80 (95% CI: 0.736‒0.87) for detection of pneumothorax, 0.77 (95% CI: 0.68‒0.86) for hemothorax, and 0.58 (95% CI: 0.5‒0.67) for pulmonary contusion. Comparison of areas under the ROC curve declared the significant superiority of ultrasonography in detection of pneumothorax (p = 0.02) and pulmonary contusion (p < 0.001). However, the diagnostic value of the two tests was equal in detection of hemothorax (p = 0.08). The results of the present study showed that ultrasonography is preferable to radiography in the initial evaluation of patients with traumatic injuries to the

  13. Diagnostic Accuracy of Ultrasonography and Radiography in Initial Evaluation of Chest Trauma Patients

    Directory of Open Access Journals (Sweden)

    Ali Vafaei

    2016-01-01

    Full Text Available Introduction: Application of chest radiography for all multiple trauma patients is associated with a significant increase in total costs, exposure to radiation, and overcrowding of the emergency department. Ultrasound has been introduced as an alternative diagnostic tool in this regard. The aim of the present study is to compare the diagnostic accuracy of chest ultrasonography and radiography in detection of traumatic intrathoracic injuries. Methods: In the present prospective cross-sectional study, patients with traumatic intrathoracic injuries, who were referred to the emergency department from December 2013 to December 2014, were assessed. The patients underwent bedside ultrasound, radiographic and computed tomography (CT scan examinations based on ATLS recommendations. Screening performance characteristics of ultrasonography and radiography were compared using SPSS 21.0. Chest CT scan was considered as gold standard. Results: 152 chest trauma patients with a mean age of 31.4 ± 13.8 years (range: 4 ‒ 67, were enrolled (77.6% male. Chest CT scan showed pulmonary contusion in 48 (31.6% patients, hemothorax in 29 (19.1%, and pneumothorax in 55 (36.2% cases. Area under the ROC curve of ultrasonography in detection of pneumothorax, hemothorax, and pulmonary contusion were 0.91 (95% CI: 0.86‒0.96, 0.86 (95% CI: 0.78‒0.94, and 0.80 (95% CI: 0.736‒0.88, respectively. Area under the ROC curve of radiography was 0.80 (95% CI: 0.736‒0.87 for detection of pneumothorax, 0.77 (95% CI: 0.68‒0.86 for hemothorax, and 0.58 (95% CI: 0.5‒0.67 for pulmonary contusion. Comparison of areas under the ROC curve declared the significant superiority of ultrasonography in detection of pneumothorax (p = 0.02 and pulmonary contusion (p < 0.001. However, the diagnostic value of the two tests was equal in detection of hemothorax (p = 0.08. Conclusion: The results of the present study showed that ultrasonography is preferable to radiography in the initial

  14. Evaluation of Position Resolution for a Prototype Whole-Body PET Detector Based on Suppressing Backgrounds by Compton Scattering

    Science.gov (United States)

    Fujihara, Kento; Emoto, Yusaku; Ito, Hiroshi; Kaneko, Naomi; Kaneko, Hideyuki; Kawai, Hideyuki; Kobayashi, Atsushi; Mizuno, Takahiro

    2018-01-01

    Existing PET (Positron Emission Tomography) systems make clear images in demonstration (measuring small PET reagent in pure water), however images in real diagnosis become unclear. The authors suspected that this problem was caused by Compton scattering in a detector. When PET systems observe plural photomultiplier tube outputs, an original emission point is regarded as centroid of the outputs. However, even if plural emission in Compton scattering occur, these systems calculate original point in the same way as single emission. Therefore, the authors considered that rejecting Compton scattering events makes PET systems much better, and made prototype counter. Main components of the prototype counter are plate-like high-growth-rate (HGR) La-GPS scintillators and wavelength shifting fibers (WLSF). HGR crystals grow 10 times as fast as a mono-crystal (a normal mono-crystal grows at 2 - 3 mm an hour). Thus, it includes microbubble and its transparency get worth. Consequently, HGR crystals usually are not used in radiation measuring instruments. However, this time they are used on the purpose. Because of their low transparency, scintillation lights come out right above and right under of emission position. Therefore, Compton scattering events is rejected easily. The prototype detector has an effective area of 300 by 300 square mm. The detector consists of 24 layers. One layer consists of HGR La-GPS scintillator of 1 mm thickness. Top and bottom surface of scintillator were covered by dual sheets of WLSF with a diameter of 0.2 mm. Sheets of WLSF on top and bottom of the scintillator make a right angle with each other, and measure X- and Y-components. Z-component is measured by difference of WLSF outputs between top and bottom. If plural layers output signals, this counter regards the event as Compton scattering event, and reject the event. Even if only a layer output signals, the event is rejected when number output signals from WLSF is more than 1.5 times of single

  15. Superlattice electroabsorption radiation detector

    International Nuclear Information System (INIS)

    Cooke, B.J.

    1993-06-01

    This paper provides a preliminary investigation of a new class of superlattice electroabsorption radiation detectors that employ direct optical modulation for high-speed, two-dimensional (2-D), high-resolution imaging. Applications for the detector include nuclear radiation measurements, tactical guidance and detection (laser radar), inertial fusion plasma studies, and satellite-based sensors. Initial calculations discussed in this paper indicate that a 1.5-μm (GaAlAs) multi-quantum-well (MQW) Fabry-Perot detector can respond directly to radiation of energies 1 eV to 10 KeV, and indirectly (with scattering targets) up through gamma, with 2-D sample rates on the order of 20 ps

  16. Evaluation of a novel helium ionization detector within the context of (low-)flow modulation comprehensive two-dimensional gas chromatography.

    Science.gov (United States)

    Franchina, Flavio A; Maimone, Mariarosa; Sciarrone, Danilo; Purcaro, Giorgia; Tranchida, Peter Q; Mondello, Luigi

    2015-07-10

    The present research is focused on the use and evaluation of a novel helium ionization detector, defined as barrier discharge ionization detector (BID), within the context of (low-)flow modulation comprehensive two-dimensional gas chromatography (FM GC×GC). The performance of the BID device was compared to that of a flame ionization detector (FID), under similar FM GC×GC conditions. Following development and optimization of the FM GC×GC method, the BID was subjected to fine tuning in relation to acquisition frequency and discharge flow. Moreover, the BID performance was measured and compared to that of the FID, in terms of extra-column band broadening, sensitivity and dynamic range. The comparative study was carried out by using standard compounds belonging to different chemical classes, along with a sample of diesel fuel. Advantages and disadvantages of the BID system, also within the context of FM GC×GC, are critically discussed. In general, the BID system was characterized by a more limited dynamic range and increased sensitivity, compared to the FID. Additionally, BID and FID contribution to band broadening was found to be similar under the operational conditions applied. Particular attention was devoted to the behaviour of the FM GC×GC-BID system toward saturated and aromatic hydrocarbons, for a possible future use in the field of mineral-oil food contamination research. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Performance evaluation of a sub-millimeter spatial resolution PET detector module using a digital silicon photomultiplier coupled LGSO array

    Energy Technology Data Exchange (ETDEWEB)

    Leem, Hyun Tae [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Choi, Yong, E-mail: ychoi@sogang.ac.kr [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Kim, Kyu Bom; Lee, Sangwon [Molecular Imaging Research & Education (MiRe) Laboratory, Department of Electronic Engineering, Sogang University, Seoul (Korea, Republic of); Yamamoto, Seiichi [Department of Medical Technology, Nagoya University Graduate School of Medicine, Nagoya (Japan); Yeom, Jung-Yeol, E-mail: jungyeol@korea.ac.kr [School of Biomedical Engineering, Korea University, Seoul (Korea, Republic of)

    2017-02-21

    In positron emission tomography (PET) for breast, brain and small animal imaging, the spatial resolution of a PET detector is crucial to obtain high quality PET images. In this study, a PET detector for sub-millimeter spatial resolution imaging purpose was assembled using 4×4 pixels of a digital silicon photomultiplier (dSiPM, DPC-3200-22-44, Philips) coupled with a 15×15 LGSO array with BaSO{sub 4} reflector, and a 1 mm thick acrylic light guide for light distribution between the dSiPM pixels. The active area of each dSiPM pixel was 3.2×3.9 mm{sup 2} and the size of each LGSO scintillator element was 0.7×0.7×6 mm{sup 3}. In this paper, we experimentally demonstrated the performance of the PET detector by measuring the energy resolution, 2D flood map, peak to valley (P/V) ratio, and coincidence resolving time (CRT). All measurements were performed at a temperature of 10±1 ℃. The average energy resolution was 15.6% (without correcting for saturation effects) at 511 keV and the best CRT was 242±5 ps. The 2D flood map obtained with an energy window of 400–600 keV demonstrated clear identification of all pixels, and the average P/V ratio of the X- and Y-directions were 7.31 and 7.81, respectively. This study demonstrated that the PET detector could be suitable for application in high resolution PET while achieving good timing resolution.

  18. The technique advantages of 16-detector multic-slice spiral CT in evaluating combined pulmonary and deep vein thromboembolism

    International Nuclear Information System (INIS)

    Xia Shuang; Qi Ji; Lei Xinwei; Wen Lianqing; Li Yiming; Liu Jisheng

    2004-01-01

    Objective: To study the scanning technique of 16-detector multic-slice spiral CT(MSCT) for combined pulmonary artery and deep vein of lower limb in pulmonary thromboembolism (PE) patients. Methods: Forty suspected pulmonary thromboembolism patients were performed both pulmonary artery angiography (CTA) and indirect deep vein venography (CTV) on 16-detector MSCT. The parameters of the latter as following: total contrast volume 120-150 ml, injection rate 4.0-4.5 ml/s (from antecubital vein), delay time 4.0 for CTA 20-23 s, CTV 120-180 s, collimation for CTA 1.25 mm and 0.625 mm, CTV 2.5 mm, scan range of CTV: from popliteal vein to the level of bilateral renal vein into the inferior vena cava. Postprocessing include MPR, MIP, and VR. The test was used to analyzed the images. Results: Twenty five patients had both pulmonary thromboembolism (PE) and deep vein thromboembolism (DVT), 8 patients had only DVT, 2 had only PE, and 5 had neither. There was no difference between different collimation in depicting thrombus. The CT value number of enhanced pulmonary artery and lower deep vein was obviously higher than the thrombus. The value of MPR, MIP, VR for PE was 100%, 100%, and 65%, The value of MPR, MIP, VR for DVT is 100%, 60%, and 50%. Conclusion: The technique of combined pulmonary CTA and deep vein CTV of 16-detector MSCT will provide a new modality for pulmonary thromboembolism patients. (author)

  19. Impact and Process Evaluation of the U.S. Department of Energy's Wind Powering America Initiative

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-05-01

    This report presents an evaluation of the impacts and processes of the former Wind Powering America(WPA) initiative sponsored by the U.S. Department of Energy (DOE). WPA has an underlying goal of dramatically increasing the use of wind energy in the U.S.

  20. 49 CFR 40.293 - What is the SAP's function in conducting the initial evaluation of an employee?

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false What is the SAP's function in conducting the... Professionals and the Return-to-Duty Process § 40.293 What is the SAP's function in conducting the initial evaluation of an employee? As a SAP, for every employee who comes to you following a DOT drug and alcohol...

  1. Protective Effect of Forced Hydration with Isotonic Saline, Potassium Chloride and Magnesium Sulfate on Cisplatin Nephrotoxicity: An Initial Evaluation

    Directory of Open Access Journals (Sweden)

    Seyed Seifollah Beladi Mousavi

    2013-12-01

    How to cite this article: Beladi Mousavi SS, Hossainzadeh M, Khanzadeh A, Hayati F, Beladi Mousavi M, Zeraati AA, et al. Protective Effect of Forced Hydration with Isotonic Saline, Potassium Chloride and Magnesium Sulfate on Cisplatin Nephrotoxicity: An Initial Evaluation. Asia Pac J Med Toxicol 2013;2:136-9.

  2. Evaluation of the LiveWell@School Food Initiative Shows Increases in Scratch Cooking and Improvement in Nutritional Content

    Science.gov (United States)

    Schober, Daniel J.; Carpenter, Leah; Currie, Venita; Yaroch, Amy L.

    2016-01-01

    Background: The purpose of this evaluation was to examine the effects of the LiveWell@School Food Initiative (LW@SFI), a Colorado-based childhood obesity prevention program that partners with school districts to enable them to serve more scratch cooked foods through culinary training, action planning, and equipment grants. Methods: This evaluation…

  3. Videoconferencing for site initiations in clinical studies: Mixed methods evaluation of usability, acceptability, and impact on recruitment.

    Science.gov (United States)

    Randell, Rebecca; Backhouse, Michael R; Nelson, E Andrea

    2016-12-01

    A critical issue for multicentre clinical studies is conducting site initiations, ensuring sites are trained in study procedures and comply with relevant governance requirements before they begin recruiting patients. How technology can support site initiations has not previously been explored. This study sought to evaluate use of off-the-shelf web-based videoconferencing to deliver site initiations for a large national multicentre study. Participants in the initiations, including podiatrists, diabetologists, trial coordinators, and research nurses, completed an online questionnaire based on the System Usability Scale (SUS) (N = 15). This was followed by semi-structured interviews, with a consultant diabetologist, a trial coordinator, and three research nurses, exploring perceived benefits and limitations of videoconferencing. The mean SUS score for the videoconferencing platform was 87.2 (SD = 13.7), suggesting a good level of usability. Interview participants perceived initiations delivered by videoconferencing as being more interactive and easier to follow than those delivered by teleconference. In comparison to face-to-face initiations, videoconferencing takes less time, easily fitting in with the work of staff at the local sites. Perceptions of impact on communication varied according to the hardware used. Off-the-shelf videoconferencing is a viable alternative to face-to-face site initiations and confers advantages over teleconferencing.

  4. Indigenous development of diamond detectors for monitoring neutrons

    International Nuclear Information System (INIS)

    Singh, Arvind; Amit Kumar; Topkar, Anita; Pithawa, C.K.

    2013-01-01

    High purity synthetic chemically vapor deposited (CVD) diamond has several outstanding characteristics that make it as an important material for detector applications specifically for extreme environmental conditions like high temperature, high radiation, and highly corrosive environments. Diamond detectors are especially considered promising for monitoring fast neutrons produced by the D-T nuclear fusion reactions in next generation fusion facilities such as ITER. When fast neutrons interact with carbon, elastic, inelastic and (n,α) type reactions can occur. These reactions can be employed for the detection of fast neutrons using diamond. We have initiated the development of diamond detectors based on synthetic CVD substrates. In this paper, the first test of a polycrystalline CVD diamond detector with fast neutrons is reported. The test results demonstrate that this detector can be used for monitoring fast neutrons. The diamond detectors have been fabricated using 5 mm x 5 mm, 300 μm polycrystalline diamond substrates. Aluminum metallization has been used on both sides of the detector to provide electrical contacts. The performance of fabricated detectors was first evaluated using current and capacitance measurements. The leakage current was observed to be stable and about a few pAs for voltages up to 300V. The capacitance-voltage characteristics showed a constant capacitance which is as expected. To confirm the response of the detector to charged particles, the pulse height spectrum (PHS) was obtained using 238 Pu- 239 Pu dual α- source. The PHS showed a continuum without any peak due to polycrystalline nature of diamond film. The response of the detector to fast neutrons has been studied using the fast neutron facility at NXF, BARC. The PHS obtained for a neutron yield of 4 x 10 8 n/s is shown. The average counts per second (cps) measured for diamond detector for different neutron yields is shown. The plot shows linearity with coefficient of determination R

  5. Preoperative short hookwire placement for small pulmonary lesions: evaluation of technical success and risk factors for initial placement failure.

    Science.gov (United States)

    Iguchi, Toshihiro; Hiraki, Takao; Matsui, Yusuke; Fujiwara, Hiroyasu; Masaoka, Yoshihisa; Tanaka, Takashi; Sato, Takuya; Gobara, Hideo; Toyooka, Shinichi; Kanazawa, Susumu

    2018-05-01

    To retrospectively evaluate the technical success of computed tomography fluoroscopy-guided short hookwire placement before video-assisted thoracoscopic surgery and to identify the risk factors for initial placement failure. In total, 401 short hookwire placements for 401 lesions (mean diameter 9.3 mm) were reviewed. Technical success was defined as correct positioning of the hookwire. Possible risk factors for initial placement failure (i.e., requirement for placement of an additional hookwire or to abort the attempt) were evaluated using logistic regression analysis for all procedures, and for procedures performed via the conventional route separately. Of the 401 initial placements, 383 were successful and 18 failed. Short hookwires were finally placed for 399 of 401 lesions (99.5%). Univariate logistic regression analyses revealed that in all 401 procedures only the transfissural approach was a significant independent predictor of initial placement failure (odds ratio, OR, 15.326; 95% confidence interval, CI, 5.429-43.267; p < 0.001) and for the 374 procedures performed via the conventional route only lesion size was a significant independent predictor of failure (OR 0.793, 95% CI 0.631-0.996; p = 0.046). The technical success of preoperative short hookwire placement was extremely high. The transfissural approach was a predictor initial placement failure for all procedures and small lesion size was a predictor of initial placement failure for procedures performed via the conventional route. • Technical success of preoperative short hookwire placement was extremely high. • The transfissural approach was a significant independent predictor of initial placement failure for all procedures. • Small lesion size was a significant independent predictor of initial placement failure for procedures performed via the conventional route.

  6. An Initial Evaluation of Tablet Devices & What Are the Next Steps?

    Science.gov (United States)

    McKillen, Tracey

    2016-01-01

    This paper describes an evaluation of tablet devices for a Graduate Entry Medical School (GEMS). The purpose of this evaluation is to assess what type of tablet device could meet the needs of a GEMS student. GEMS requirements for the evaluation include; using the tablet device to replace paper teaching resources in lectures and tutorials and…

  7. Evaluating Open Source Software for Use in Library Initiatives: A Case Study Involving Electronic Publishing

    Science.gov (United States)

    Samuels, Ruth Gallegos; Griffy, Henry

    2012-01-01

    This article discusses best practices for evaluating open source software for use in library projects, based on the authors' experience evaluating electronic publishing solutions. First, it presents a brief review of the literature, emphasizing the need to evaluate open source solutions carefully in order to minimize Total Cost of Ownership. Next,…

  8. SU-E-T-644: Evaluation of Angular Dependence Correction for 2D Array Detector Using for Quality Assurance of Volumetric Modulated Arc Therapy

    International Nuclear Information System (INIS)

    Karthikeyan, N; Ganesh, K M; Vikraman, S; Shariff, MH

    2014-01-01

    Purpose: To evaluate the angular dependence correction for Matrix Evolution 2D array detector in quality assurance of volumetric modulated arc therapy(VMAT). Methods: Total ten patients comprising of different sites were planned for VMAT and taken for the study. Each plan was exposed on Matrix Evolution 2D array detector with Omnipro IMRT software based on the following three different methods using 6MV photon beams from Elekta Synergy linear accelerator. First method, VMAT plan was delivered on Matrix Evolution detector as it gantry mounted with dedicated holder with build-up of 2.3cm. Second, the VMAT plan was delivered with the static gantry angle on to the table mounted setup. Third, the VMAT plan was delivered with actual gantry angle on Matrix Evolution detector fixed in Multicube phantom with gantry angle sensor and angular dependence correction were applied to quantify the plan quality. For all these methods, the corresponding QA plans were generated in TPS and the dose verification was done for both point and 2D fluence analysis with pass criteria of 3% dose difference and 3mm distance to agreement. Results: The measured point dose variation for the first method was observed as 1.58±0.6% of mean and SD with TPS calculated. For second and third method, the mean and standard deviation(SD) was observed as 1.67±0.7% and 1.85±0.8% respectively. The 2D fluence analysis of measured and TPS calculated has the mean and SD of 97.9±1.1%, 97.88±1.2% and 97.55±1.3% for first, second and third methods respectively. The calculated two-tailed Pvalue for point dose and 2D fluence analysis shows the insignificance with values of 0.9316 and 0.9015 respectively, among the different methods of QA. Conclusion: The qualitative evaluation of angular dependence correction for Matrix Evolution 2D array detector shows its competency in accuracy of quality assurance measurement of composite dose distribution of volumetric modulated arc therapy

  9. Quantitative image quality evaluation of pixel-binning in a flat-panel detector for x-ray fluoroscopy

    International Nuclear Information System (INIS)

    Srinivas, Yogesh; Wilson, David L.

    2004-01-01

    X-ray fluoroscopy places stringent design requirements on new flat-panel (FP) detectors, requiring both low-noise electronics and high data transfer rates. Pixel-binning, wherein data from more that one detector pixel are collected simultaneously, not only lowers the data transfer rate but also increases x-ray counts and pixel signal-to-noise ratio (SNR). In this study, we quantitatively assessed image quality of image sequences from four acquisition methods; no-binning and three types of binning; in synthetic images using a clinically relevant task of detecting an extended guidewire in a four-alternative forced-choice paradigm. Binning methods were conventional data-line (D) and gate-line (G) binning, and a novel method in which alternate frames in an image sequence used D and G binning. Two detector orientations placed the data lines either parallel or perpendicular to the guide wire. At a low exposure of 0.6 μR (1.548x10 -10 C/kg) per frame, irrespective of detector orientation, D binning with its reduced electronic noise was significantly (p -10 C/kg) per frame, with data lines parallel to the guidewire, detection with D binning was significantly (p<0.1) better than G binning. However, with data lines perpendicular to the guidewire, G binning was significantly (p<0.1) better than D binning because the partial area effect was reduced. Alternate binning was the best binning method when results were averaged over both orientations, and it was as good as the best binning method at either orientation. In addition, at low and high exposures, alternate binning gave a temporally fused image with a smooth guidewire, an important image quality feature not assessed in a detection experiment. While at high exposure, detection with no binning was as good, or better, than the best binning method, it might be impractical at fluoroscopy imaging rates. A computational observer model based on signal detection theory successfully fit data and was used to predict effects of

  10. [Positron emission tomography combined with computed tomography in the initial evaluation and response assessment in primary central nervous system lymphoma].

    Science.gov (United States)

    Mercadal, Santiago; Cortés-Romera, Montserrat; Vélez, Patricia; Climent, Fina; Gámez, Cristina; González-Barca, Eva

    2015-06-08

    To evaluate the role of positron emission tomography combined with computed tomography (PET-CT) in the initial evaluation and response assessment in primary central nervous system lymphoma (PCNSL). Fourteen patients (8 males) with a median age 59.5 years diagnosed of PCNSL. A brain PET-CT and magnetic resonance imaging (MRI) were performed in the initial evaluation. In 7 patients a PET-CT after treatment was performed. PET-CT showed at diagnosis 31 hypermetabolic focuses and MRI showed 47 lesions, with a good grade of concordance between both (k = 0.61; P = .005). In the response assessment, correlation between both techniques was good, and PET-CT was helpful in the appreciation of residual MRI lesions. Overall survival at 2 years of negative vs. positive PET-CT at the end of treatment was 100 vs. 37.5%, respectively (P = .045). PET-CT can be useful in the initial evaluation of PCNSL, and especially in the assessment of response. Despite the fact that PET-CT detects less small lesions than MRI, a good correlation between MRI and PET-CT was observed. It is effective in the evaluation of residual lesions. Prospective studies are needed to confirm their possible prognostic value. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  11. Shaped detector

    International Nuclear Information System (INIS)

    Carlson, R.W.

    1981-01-01

    A radiation detector or detector array which has a non-constant spatial response, is disclosed individually and in combination with a tomographic scanner. The detector has a first dimension which is oriented parallel to the plane of the scan circle in the scanner. Along the first dimension, the detector is most responsive to radiation received along a centered segment of the dimension and less responsive to radiation received along edge segments. This non-constant spatial response can be achieved in a detector comprised of a scintillation crystal and a photoelectric transducer. The scintillation crystal in one embodiment is composed of three crystals arranged in layers, with the center crystal having the greatest light conversion efficiency. In another embodiment, the crystal is covered with a reflective substance around the center segment and a less reflective substance around the remainder. In another embodiment, an optical coupling which transmits light from adjacent the center segment with the greatest intensity couples the scintillation crystal and the photoelectric transducer. In yet another embodiment, the photoelectric transducer comprises three photodiodes, one receiving light produced adjacent the central segment and the other two receiving light produced adjacent the edge segments. The outputs of the three photodiodes are combined with a differential amplifier

  12. Approaches to evaluating climate change impacts on species: A guide to initiating the adaptation planning process

    Science.gov (United States)

    Erika L. Rowland; Jennifer E. Davison; Lisa J. Graumlich

    2011-01-01

    Assessing the impact of climate change on species and associated management objectives is a critical initial step for engaging in the adaptation planning process. Multiple approaches are available. While all possess limitations to their application associated with the uncertainties inherent in the data and models that inform their results, conducting and incorporating...

  13. An evaluation of insulin therapy initiation among patients with type 2 ...

    African Journals Online (AJOL)

    Background: Clinically effective interventions that could reduce diabetic patients' risk of long-term complications are needed to contain the rising cost of diabetes care associated with the increasing prevalence of this condition. Good glycaemic control needs to be rapidly attained and maintained by the appropriate initiation ...

  14. "Doing Geography": Evaluating an Independent Geographic Inquiry Assessment Task in an Initial Teacher Education Program

    Science.gov (United States)

    Harte, Wendy; Reitano, Paul

    2016-01-01

    The assessment task of the final course in a bachelor of secondary education program is examined for opportunities for preservice geography teachers to achieve the course aims of integrating, consolidating, applying, and reflecting on the knowledge and skills they have learned during their initial teacher education program. The results show that…

  15. Cryogenic detectors for particle physics

    International Nuclear Information System (INIS)

    Gonzalez-Mestres, L.; Perret-Gallix, D.

    1988-11-01

    A comprehensive introduction to cryogenic detector developments for particle physics is presented, covering conventional detectors cooled to low temperature (scintillators and semiconductors), superconductive and thermal sensitive devices, as well as the basics of cold electronics. After giving a critical overview of current work, we elaborate on possible new ways for further improvements and briefly evaluate the feasibility of the main proposed applications

  16. SU-F-T-474: Evaluation of Dose Perturbation, Temperature and Sensitivity Variation With Accumulated Dose of MOSFET Detector

    Energy Technology Data Exchange (ETDEWEB)

    Ganesan, B; Prakasarao, A; Singaravelu, G [Anna University, Chennai, TamilNadu (India); Palraj, T; Rai, R [Dr. Rai Memorial Cancer Institute, Chennai, TamilNadu (India)

    2016-06-15

    Purpose: The use of mega voltage gamma and x-ray sources with their skin sparring qualities in radiation therapy has been a boon in relieving patient discomfort and allowing high tumor doses to be given with fewer restrictions due to radiation effects in the skin. However, high doses given to deep tumors may require careful consideration of dose distribution in the buildup region in order to avoid irreparable damage to the skin. Methods: To measure the perturbation of MOSFET detector in Co60,6MV and 15MV the detector was placed on the surface of the phantom covered with the brass build up cap. To measure the effect of temperature the MOSFET detector was kept on the surface of hot water polythene container and the radiation was delivere. In order to measure the sensitivity variation with accumulated dose Measurements were taken by delivering the dose of 200 cGy to MOSFET until the MOSFET absorbed dose comes to 20,000 cGy Results: the Measurement was performed by positioning the bare MOSFET and MOSFET with brass build up cap on the top surface of the solid water phantom for various field sizes in order to find whether there is any attenuation caused in the dose distribution. The response of MOSFET was monitored for temperature ranging from 42 degree C to 22 degree C. The integrated dose dependence of MOSFET dosimeter sensitivity over different energy is not well characterized. This work investigates the dual-bias MOSFET dosimeter sensitivity response to 6 MV and 15 MV beams. Conclusion: From this study it is observed that unlike diode, bare MOSFET does not perturb the radiation field.. It is observed that the build-up influences the temperature dependency of MOSFET and causes some uncertainty in the readings. In the case of sensitivity variation with accumulated dose MOSFET showed higher sensitivity with dose accumulation for both the energies.

  17. SU-F-T-474: Evaluation of Dose Perturbation, Temperature and Sensitivity Variation With Accumulated Dose of MOSFET Detector

    International Nuclear Information System (INIS)

    Ganesan, B; Prakasarao, A; Singaravelu, G; Palraj, T; Rai, R

    2016-01-01

    Purpose: The use of mega voltage gamma and x-ray sources with their skin sparring qualities in radiation therapy has been a boon in relieving patient discomfort and allowing high tumor doses to be given with fewer restrictions due to radiation effects in the skin. However, high doses given to deep tumors may require careful consideration of dose distribution in the buildup region in order to avoid irreparable damage to the skin. Methods: To measure the perturbation of MOSFET detector in Co60,6MV and 15MV the detector was placed on the surface of the phantom covered with the brass build up cap. To measure the effect of temperature the MOSFET detector was kept on the surface of hot water polythene container and the radiation was delivere. In order to measure the sensitivity variation with accumulated dose Measurements were taken by delivering the dose of 200 cGy to MOSFET until the MOSFET absorbed dose comes to 20,000 cGy Results: the Measurement was performed by positioning the bare MOSFET and MOSFET with brass build up cap on the top surface of the solid water phantom for various field sizes in order to find whether there is any attenuation caused in the dose distribution. The response of MOSFET was monitored for temperature ranging from 42 degree C to 22 degree C. The integrated dose dependence of MOSFET dosimeter sensitivity over different energy is not well characterized. This work investigates the dual-bias MOSFET dosimeter sensitivity response to 6 MV and 15 MV beams. Conclusion: From this study it is observed that unlike diode, bare MOSFET does not perturb the radiation field.. It is observed that the build-up influences the temperature dependency of MOSFET and causes some uncertainty in the readings. In the case of sensitivity variation with accumulated dose MOSFET showed higher sensitivity with dose accumulation for both the energies.

  18. BES detector

    International Nuclear Information System (INIS)

    Bai, J.Z.; Bian, Q.; Chen, G.M.; Chen, L.J.; Chen, S.N.; Chen, Y.Q.; Chen, Z.Q.; Chi, Y.K.; Cui, H.C.; Cui, X.Z.; Deng, S.S.; Deng, Y.W.; Ding, H.L.; Dong, B.Z.; Dong, X.S.; Du, X.; Du, Z.Z.; Feng, C.; Feng, Z.; Fu, Z.S.; Gao, C.S.; Gao, M.L.; Gao, S.Q.; Gao, W.X.; Gao, Y.N.; Gu, S.D.; Gu, W.X.; Guan, Y.Z.; Guo, H.F.; Guo, Y.N.; Guo, Y.Y.; Han, S.W.; Han, Y.; Hao, W.; He, J.; He, K.R.; He, M.J.; Hou, X.J.; Hu, G.Y.; Hu, J.S.; Hu, J.W.; Huang, D.Q.; Huang, Y.Z.; Jia, Q.P.; Jiang, C.H.; Ju, Q.; Lai, Y.F.; Lang, P.F.; Li, D.S.; Li, F.; Li, H.; Li Jia; Li, J.T.; Li Jin; Li, L.L.; Li, P.Q.; Li, Q.M.; Li, R.B.; Li, S.Q.; Li, W.; Li, W.G.; Li, Z.X.; Liang, G.N.; Lin, F.C.; Lin, S.Z.; Lin, W.; Liu, Q.; Liu, R.G.; Liu, W.; Liu, X.; Liu, Z.A.; Liu, Z.Y.; Lu, C.G.; Lu, W.D.; Lu, Z.Y.; Lu, J.G.; Ma, D.H.; Ma, E.C.; Ma, J.M.; Mao, H.S.; Mao, Z.P.; Meng, X.C.; Ni, H.L.; Nie, J.; Nie, Z.D.; Niu, W.P.; Pan, L.J.; Qi, N.D.; Qian, J.J.; Qu, Y.H.; Que, Y.K.; Rong, G.; Ruan, T.Z.; Shao, Y.Y.; Shen, B.W.; Shen, D.L.; Shen, J.; Sheng, H.Y.; Sheng, J.P.; Shi, H.Z.; Song, X.F.; Sun, H.S.; Tang, F.K.; Tang, S.Q.; Tian, W.H.; Wang, F.; Wang, G.Y.; Wang, J.G.; Wang, J.Y.; Wang, L.S.; Wang, L.Z.; Wang, M.; Wang, P.; Wang, P.L.; Wang, S.M.; Wang, S.Q.; Wang, T.J.; Wang, X.W.; Wang, Y.Y.; Wang, Z.H.; Wang, Z.J.; Wei, C.L.; Wei, Z.Z.; Wu, J.W.; Wu, S.H.; Wu, S.Q.; Wu, W.M.; Wu, X.D.; Wu, Z.D.; Xi, D.M.; Xia, X.M.; Xiao, J.; Xie, P.P.; Xie, X.X.; Xu, J.G.; Xu, R.S.; Xu, Z.Q.; Xuan, B.C.; Xue, S.T.; Yan, J.; Yan, S.P.; Yan, W.G.; Yang, C.Z.; Yang, C.M.; Yang, C.Y.; Yang, X.F.; Yang, X.R.; Ye, M.H.; Yu, C.H.; Yu, C.S.; Yu, Z.Q.; Zhang, B.Y.; Zhang, C.D.; Zhang, C.C.; Zhang, C.Y.; Zhang, D.H.; Zhang, G.; Zhang, H.Y.; Zhang, H.L.; Zhang, J.W.; Zhang, L.S.; Zhang, S.Q.; Zhang, Y.P.; Zhang, Y.; Zhang, Y.M.; Zhao, D.X.; Zhao, J.W.; Zhao, M.; Zhao, P.D.; Zhao, P.P.; Zhao, W.R.; Zhao, Z.G.; Zhao, Z.Q.; Zheng, J.P.; Zheng, L.S.; Zheng, M.; Zheng, W.S.; Zheng, Z.P.; Zhong, G.P.; Zhou, G.P.; Zhou, H.S.; Zhou, J.; Zhou Li; Zhou Lin; Zhou, M.; Zhou, Y.S.; Zhou, Y.H.; Zhu, G.S.; Zhu, Q.M.; Zhu, S.G.; Zhu, Y.C.; Zhu, Y.S.; Zhuang, B.A.

    1994-01-01

    The Beijing Spectrometer (BES) is a general purpose solenoidal detector at the Beijing Electron Positron Collider (BEPC). It is designed to study exclusive final states in e + e - annihilations at the center of mass energy from 3.0 to 5.6 GeV. This requires large solid angle coverage combined with good charged particle momentum resolution, good particle identification and high photon detection efficiency at low energies. In this paper we describe the construction and the performance of BES detector. (orig.)

  19. Continuous on-line monitoring of left ventricular function with a new nonimaging detector:validation and clinical use in the evaluation of patients post angioplasty.

    Science.gov (United States)

    Breisblatt, W M; Schulman, D S; Follansbee, W P

    1991-06-01

    A new miniaturized nonimaging radionuclide detector (Cardioscint, Oxford, England) was evaluated for the continuous on-line assessment of left ventricular function. This cesium iodide probe can be placed on the patient's chest and can be interfaced to an IBM compatible personal computer conveniently placed at the patient's bedside. This system can provide a beat-to-beat or gated determination of left ventricular ejection fraction and ST segment analysis. In 28 patients this miniaturized probe was correlated against a high resolution gamma camera study. Over a wide range of ejection fraction (31% to 76%) in patients with and without regional wall motion abnormalities, the correlation between the Cardioscint detector and the gamma camera was excellent (r = 0.94, SEE +/- 2.1). This detector system has high temporal (10 msec) resolution, and comparison of peak filling rate (PFR) and time to peak filling (TPFR) also showed close agreement with the gamma camera (PFR, r = 0.94, SEE +/- 0.17; TPFR, r = 0.92, SEE +/- 6.8). In 18 patients on bed rest the long-term stability of this system for measuring ejection fraction and ST segments was verified. During the monitoring period (108 +/- 28 minutes) only minor changes in ejection fraction occurred (coefficient of variation 0.035 +/- 0.016) and ST segment analysis showed no significant change from baseline. To determine whether continuous on-line measurement of ejection fraction would be useful after coronary angioplasty, 12 patients who had undergone a successful procedure were evaluated for 280 +/- 35 minutes with the Cardioscint system.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Ruggedization of CdZnTe detectors and detector assemblies for radiation detection applications

    Energy Technology Data Exchange (ETDEWEB)

    Lu, P.H., E-mail: pinghe.lu@redlen.com; Gomolchuk, P.; Chen, H.; Beitz, D.; Grosser, A.W.

    2015-06-01

    This paper described improvements in the ruggedization of CdZnTe detectors and detector assemblies for use in radiation detection applications. Research included experimenting with various conductive and underfill adhesive material systems suitable for CZT substrates. A detector design with encapsulation patterning was developed to protect detector surfaces and to control spacing between CZT anode and PCB carrier. Robustness of bare detectors was evaluated through temperature cycling and metallization shear testing. Attachment processes using well-chosen adhesives and PCB carrier materials were optimized to improve reliability of detector assemblies, resulted in Improved Attachment Detector Assembly. These detector assemblies were subjected to aggressive temperature cycling, and varying levels of drop/shock and vibration, in accordance with modified JEDEC, ANSI and FedEx testing standards, to assess their ruggedness. Further enhanced detector assembly ruggedization methods were investigated involving adhesive conformal coating, potting and dam filling on detector assemblies, which resulted in the Enhanced Ruggedization Detector Assembly. Large numbers of CZT detectors and detector assemblies with 5 mm and 15 mm thick, over 200 in total, were tested. Their performance was evaluated by exposure to various radioactive sources using comprehensive predefined detector specifications and testing protocols. Detector assemblies from improved attachment and enhanced ruggedization showed stable performances during the harsh environmental condition tests. In conclusion, significant progress has been made in improving the reliability and enhancing the ruggedness of CZT detector assemblies for radiation detection applications deployed in operational environments. - Highlights: • We developed ruggedization methods to enhance reliability of CZT detector assemblies. • Attachment of CZT radiation detectors was improved through comparative studies. • Bare detector metallization

  1. Ultra-high-resolution C-arm flat-detector CT angiography evaluation reveals 3-fold higher association rate for sporadic intracranial cavernous malformations and developmental venous anomalies: a retrospective study in consecutive 58 patients with 60 cavernous malformations

    Energy Technology Data Exchange (ETDEWEB)

    Kocak, Burak [Aksaray State Hospital, Department of Radiology, Aksaray (Turkey); Kizilkilic, Osman; Kocer, Naci; Islak, Civan [Istanbul University, Department of Radiology, Cerrahpasa Medical Faculty, Istanbul (Turkey); Oz, Buge; Bakkaloglu, Dogu Vuralli [Istanbul University, Department of Pathology, Cerrahpasa Medical Faculty, Istanbul (Turkey); Isler, Cihan [Istanbul University, Department of Neurosurgery, Cerrahpasa Medical Faculty, Istanbul (Turkey)

    2017-06-15

    The imaging and surgical literature has confusing association rates for the association between sporadic intracranial cavernous malformations (CMs) and developmental venous anomalies (DVAs). In this study, our purpose was to determine the association rate using ultra-high-resolution C-arm flat-detector CT angiography (FDCTA) and compare it with literature. Fifty-eight patients with 60 sporadic intracranial CMs that underwent an FDCTA study were included in our retrospective study. Re-evaluation of radiological data was performed based on the criteria defined by authors. Isotropic volumetric reconstructions with ultra-high resolution (voxel size of 102 μm{sup 3} for initial; 67 μm{sup 3} and 32 μm{sup 3} for further evaluation) were used for assessment. Sixteen patients underwent surgery for excision of their CMs. Fifty-one of all patients (87.9 %) were associated with a DVA. Undefined local venous structures (UD-LVSs) were observed in the remaining 7 patients (12.1 %). The strength of interobserver agreement was excellent [kappa(k) coefficient = 0.923]. Ultra-high-resolution FDCTA evaluation of CMs and DVAs reveals 3-fold higher association rate compared to the literature. FDCTA for patients with sporadic CMs could help identify the associated DVAs that remained undetected or unclear with other imaging modalities, which can be useful in decision-making processes, planning surgery, and during operation. (orig.)

  2. Physiotherapy in hip and knee osteoarthritis: development of a practice guideline concerning initial assessment, treatment and evaluation.

    Science.gov (United States)

    Peter, W F; Jansen, M J; Hurkmans, E J; Bloo, H; Dekker, J; Dilling, R G; Hilberdink, W; Kersten-Smit, C; de Rooij, M; Veenhof, C; Vermeulen, H M; de Vos, R J; Schoones, J W; Vliet Vlieland, T P

    2011-01-01

    An update of a Dutch physiotherapy practice guideline in Hip and Knee Osteoarthritis (HKOA) was made, based on current evidence and best practice. A guideline steering committee, comprising 10 expert physiotherapists, selected topics concerning the guideline chapters: initial assessment, treatment and evaluation. With respect to treatment a systematic literature search was performed using various databases, and the evidence was graded (1-4). For the initial assessment and evaluation mainly review papers and textbooks were used. Based on evidence and expert opinion, recommendations were formulated. A first draft of the guideline was reviewed by 17 experts from different professional backgrounds. A second draft was field-tested by 45 physiotherapists. In total 11 topics were selected. For the initial assessment, three recommendations were formulated, pertaining to history taking, red flags, and formulating treatment goals. Concerning treatment, 7 recommendations were formulated; (supervised) exercise therapy, education and self management interventions, a combination of exercise and manual therapy, postoperative exercise therapy and taping of the patella were recommended. Balneotherapy and hydrotherapy in HKOA, and thermotherapy, TENS, and Continuous Passive Motion in knee OA were neither recommended nor discouraged. Massage therapy, ultrasound, electrotherapy, electromagnetic field, Low Level Laser Therapy, preoperative physiotherapy and education could not be recommended. For the evaluation of treatment goals the following measurement instruments were recommended: Lequesne index, Western Ontario and McMaster Universities osteoarthritis index, Hip disability and Osteoarthritis Outcome Score and Knee injury and Osteoarthritis Outcome Score, 6-minute walktest, Timed Up and Go test, Patient Specific Complaint list, Visual Analoge Scale for pain, Intermittent and Constant OsteoArthritis Pain Questionnaire, goniometry, Medical Research Council for strength, handheld

  3. Initial evaluation of ultrasonic attenuation measurements for estimating fracture toughness of RPV steels

    Energy Technology Data Exchange (ETDEWEB)

    Hiser, A.L. Jr.; Green, R.E. Jr. [Johns Hopkins Univ., Baltimore, MD (United States). Center for Nondestructive Evaluation

    1999-08-01

    Neutron bombardment of reactor pressure vessel (RPV) steels causes reductions in fracture toughness in these steels, termed neutron irradiation embrittlement. Currently, there are no accepted methods for nondestructive determination of the extent of the irradiation embrittlement nor the actual fracture toughness of the reactor pressure vessel. This paper provides initial results of an effort addressing the use of ultrasonic attenuation as a suitable parameter for nondestructive determination of irradiation embrittlement in RPV steels. (orig.)

  4. Evaluating methamphetamine use and risks of injection initiation among street youth: the ARYS study

    Directory of Open Access Journals (Sweden)

    Montaner Julio SG

    2006-05-01

    Full Text Available Abstract Many Canadian cities are experiencing ongoing infectious disease and overdose epidemics among injection drug users (IDU. These health concerns have recently been exacerbated by the increasing availability and use of methamphetamine. The challenges of reducing health-related harms among IDU have led to an increased recognition that strategies to prevent initiation into injection drug use must receive renewed focus. In an effort to better explore the factors that may protect against or facilitate entry into injection drug use, the At Risk Youth Study (ARYS has recently been initiated in Vancouver, Canada. The local setting is unique due to the significant infrastructure that has been put in place to reduce HIV transmission among active IDU. The ARYS study will seek to examine the impact of these programs, if any, on non-injection drug users. In addition, Vancouver has been the site of widespread use of methamphetamine in general and has seen a substantial increase in the use of crystal methamphetamine among street youth. Hence, the ARYS cohort is well positioned to examine the harms associated with methamphetamine use, including its potential role in facilitating initiation into injection drug use. This paper provides some background on the epidemiology of illicit drug use among street youth in North America and outlines the methodology of ARYS, a prospective cohort study of street youth in Vancouver, Canada.

  5. [Evaluation of the influence of humidity and temperature on the drug stability by initial average rate experiment].

    Science.gov (United States)

    He, Ning; Sun, Hechun; Dai, Miaomiao

    2014-05-01

    To evaluate the influence of temperature and humidity on the drug stability by initial average rate experiment, and to obtained the kinetic parameters. The effect of concentration error, drug degradation extent, humidity and temperature numbers, humidity and temperature range, and average humidity and temperature on the accuracy and precision of kinetic parameters in the initial average rate experiment was explored. The stability of vitamin C, as a solid state model, was investigated by an initial average rate experiment. Under the same experimental conditions, the kinetic parameters obtained from this proposed method were comparable to those from classical isothermal experiment at constant humidity. The estimates were more accurate and precise by controlling the extent of drug degradation, changing humidity and temperature range, or by setting the average temperature closer to room temperature. Compared with isothermal experiments at constant humidity, our proposed method saves time, labor, and materials.

  6. Visual grading analysis of digital neonatal chest phantom X-ray images: Impact of detector type, dose and image processing on image quality.

    Science.gov (United States)

    Smet, M H; Breysem, L; Mussen, E; Bosmans, H; Marshall, N W; Cockmartin, L

    2018-07-01

    To evaluate the impact of digital detector, dose level and post-processing on neonatal chest phantom X-ray image quality (IQ). A neonatal phantom was imaged using four different detectors: a CR powder phosphor (PIP), a CR needle phosphor (NIP) and two wireless CsI DR detectors (DXD and DRX). Five different dose levels were studied for each detector and two post-processing algorithms evaluated for each vendor. Three paediatric radiologists scored the images using European quality criteria plus additional questions on vascular lines, noise and disease simulation. Visual grading characteristics and ordinal regression statistics were used to evaluate the effect of detector type, post-processing and dose on VGA score (VGAS). No significant differences were found between the NIP, DXD and CRX detectors (p>0.05) whereas the PIP detector had significantly lower VGAS (pProcessing did not influence VGAS (p=0.819). Increasing dose resulted in significantly higher VGAS (plevels but not image post-processing changes. VGA showed a DAK/image value above which perceived IQ did not improve, potentially useful for commissioning. • A VGA study detects IQ differences between detectors and dose levels. • The NIP detector matched the VGAS of the CsI DR detectors. • VGA data are useful in setting initial detector air kerma level. • Differences in NNPS were consistent with changes in VGAS.

  7. Baseline Survey for an Impact Evaluation of the Greenbelt Transformation Initiative in South Sudan

    Data.gov (United States)

    US Agency for International Development — This data set is derived from a 2013 household baseline survey in the country's Greenbelt region as part of an impact evaluation of the Food, Agribusiness, and Rural...

  8. Integrated corridor management initiative : demonstration phase evaluation. Dallas institutional and organizational analysis test plan.

    Science.gov (United States)

    2000-10-01

    The Advanced Rural Traveler Information System (ARTIS) began development June 30, 1995. While a number of activities were underway to operationally test and evaluate metro or urban traveler information systems in the 75 target markets, ARTIS setout t...

  9. Tru-cut needle pleural biopsy and cytology as the initial procedure in the evaluation of pleural effusion.

    Science.gov (United States)

    Botana Rial, Maribel; Briones Gómez, Andrés; Ferrando Gabarda, José Ramón; Cifuentes Ruiz, José Fernando; Guarín Corredor, María Juliana; Manchego Frach, Nuria; Cases Viedma, Enrique

    2014-08-01

    The evaluation of pleural effusion (PE) includes various techniques, including pleural biopsy (PB). Our aim was to study the diagnostic yield of Tru-Cut needle PB (TCPB) and to define clinical/radiological situations in which TCPB might be indicated as an initial procedure. Retrospective study of TCPB in a hospital centre (2010-2012). Cases of pleural lesions without effusion were excluded. Clinical and radiological variables, diagnostic yield, TCPB complications and factors associated with the diagnostic yield of the combination of TCPB and thoracocentesis as initial procedure were analysed. One hundred and twenty-seven (127) TCPB were reviewed: 29.1% were cases of malignant PE and in 18.9% the cause of the PE could not be determined. The diagnostic yield of TCPB for tuberculosis was 76.5% (13/17) and 54% (20/37) for malignant PE. Complications occurred in 4.7% of the cases. In 72 patients with a final definitive diagnosis, TCPB was performed at the same time as the initial thoracocentesis. Diagnostic yield for the combination of TCPB/cytology as an initial technique was 43% (31/72) compared to 12.5% (9/72) for cytology only (p=0.01). The only predictive variable for the indication of TCBP as an initial technique was a PE volume>2/3 (P=.04). TCPB is safe and provides an acceptable diagnostic yield, particularly when combined with simultaneous cytology in the evaluation of PE of various aetiologies. Radiological criteria may help guide the selection of patients who could benefit from this technique as an initial procedure combined with thoracocentesis. Copyright © 2013 SEPAR. Published by Elsevier Espana. All rights reserved.

  10. Vertex detectors

    International Nuclear Information System (INIS)

    Lueth, V.

    1992-07-01

    The purpose of a vertex detector is to measure position and angles of charged particle tracks to sufficient precision so as to be able to separate tracks originating from decay vertices from those produced at the interaction vertex. Such measurements are interesting because they permit the detection of weakly decaying particles with lifetimes down to 10 -13 s, among them the τ lepton and charm and beauty hadrons. These two lectures are intended to introduce the reader to the different techniques for the detection of secondary vertices that have been developed over the past decades. The first lecture includes a brief introduction to the methods used to detect secondary vertices and to estimate particle lifetimes. It describes the traditional technologies, based on photographic recording in emulsions and on film of bubble chambers, and introduces fast electronic registration of signals derived from scintillating fibers, drift chambers and gaseous micro-strip chambers. The second lecture is devoted to solid state detectors. It begins with a brief introduction into semiconductor devices, and then describes the application of large arrays of strip and pixel diodes for charged particle tracking. These lectures can only serve as an introduction the topic of vertex detectors. Time and space do not allow for an in-depth coverage of many of the interesting aspects of vertex detector design and operation

  11. Smoke detectors

    International Nuclear Information System (INIS)

    Macdonald, E.

    1976-01-01

    A smoke detector is described consisting of a ventilated ionisation chamber having a number of electrodes and containing a radioactive source in the form of a foil supported on the surface of the electrodes. This electrode consists of a plastic material treated with graphite to render it electrically conductive. (U.K.)

  12. Semiconductor Detectors

    International Nuclear Information System (INIS)

    Cortina, E.

    2007-01-01

    Particle detectors based on semiconductor materials are among the few devices used for particle detection that are available to the public at large. In fact we are surrounded by them in our daily lives: they are used in photoelectric cells for opening doors, in digital photographic and video camera, and in bar code readers at supermarket cash registers. (Author)

  13. Capillary detectors

    International Nuclear Information System (INIS)

    Konijn, J.; Winter, K.; Vilain, P.; Wilquet, G.; Fabre, J.P.; Kozarenko, E.; Kreslo, I.; Goldberg, J.; Hoepfner, K.; Bay, A.; Currat, C.; Koppenburg, P.; Frekers, D.; Wolff, T.; Buontempo, S.; Ereditato, A.; Frenkel, A.; Liberti, B.; Martellotti, G.; Penso, G.; Ekimov, A.; Golovkin, S.; Govorun, V.; Medvedkov, A.; Vasil'chenko, V.

    1998-01-01

    The option for a microvertex detector using glass capillary arrays filled with liquid scintillator is presented. The status of capillary layers development and possible read-out techniques for high rate environment are reported. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  14. Is it time to scrap Scadding and adopt computed tomography for initial evaluation of sarcoidosis? [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Andrew Levy

    2018-05-01

    Full Text Available In this review, we argue for the use of high-resolution computed tomography (HRCT over chest X-ray in the initial evaluation of patients with sarcoidosis. Chest X-ray, which has long been used to classify disease severity and offer prognostication in sarcoidosis, has clear limitations compared with HRCT, including wider interobserver variability, a looser association with lung function, and poorer sensitivity to detect important lung manifestations of sarcoidosis. In addition, HRCT offers a diagnostic advantage, as it better depicts targets for biopsy, such as mediastinal/hilar lymphadenopathy and focal parenchymal disease. Newer data suggest that specific HRCT findings may be associated with important prognostic outcomes, such as increased mortality. As we elaborate in this update, we strongly recommend the use of HRCT in the initial evaluation of the patient with sarcoidosis.

  15. Evaluation of the probability of crack initiation and crack instability for a pipe with a semi-elliptical crack

    International Nuclear Information System (INIS)

    Le Delliou, P.; Hornet, P.

    2001-01-01

    This paper presents some work conducted at EDF R and D Division to evaluate the probability that a semi-elliptical crack in a pipe not only initiates but also propagates when submitted to mechanical loading such as bending and pressure combined or not with a thermal shock. The first part is related to the description of the mechanical model: the simplified methods included in the French RSE-M Code used to evaluate the J-integral as well as the principle of the determination of the crack propagation. Then, the way this deterministic approach is combined to a reliability code is described. Finally, an example is shown: the initiation and the instability of a semi-elliptical crack in a pipe submitted to combined pressure and bending moment. (author)

  16. Singapore Cancer Network (SCAN) Guidelines for the Initial Evaluation, Diagnosis, and Management of Extremity Soft Tissue Sarcoma and Osteosarcoma.

    Science.gov (United States)

    2015-10-01

    The SCAN sarcoma workgroup aimed to develop Singapore Cancer Network (SCAN) clinical practice guidelines for the initial evaluation, diagnosis, and management of extremity soft tissue sarcoma and osteosarcoma. The workgroup utilised a consensus approach to create high quality evidence-based clinical practice guidelines suited for our local setting. Various international guidelines from the fields of radiology, pathology, orthopaedic surgery, medical, radiation and paediatric oncology were reviewed, including those developed by von Mehren Metal (J Natl Compr Canc Netw 2014), the National Collaborating Centre for Cancer (2006), the European Sarcoma Network Working Group (2012) and Grimer RJ et al (Sarcoma 2008). Our clinical practice guidelines contextualised to the local patient will streamline care and improve clinical outcomes for patients with extremity soft tissue and osteosarcoma. These guidelines form the SCAN Guidelines 2015 for the initial evaluation, diagnosis, and management of extremity soft tissue sarcoma and osteosarcoma.

  17. Initial Probabilistic Evaluation of Reactor Pressure Vessel Fracture with Grizzly and Raven

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, Benjamin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hoffman, William [Univ. of Idaho, Moscow, ID (United States); Sen, Sonat [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rabiti, Cristian [Idaho National Lab. (INL), Idaho Falls, ID (United States); Dickson, Terry [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bass, Richard [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-10-01

    The Grizzly code is being developed with the goal of creating a general tool that can be applied to study a variety of degradation mechanisms in nuclear power plant components. The first application of Grizzly has been to study fracture in embrittled reactor pressure vessels (RPVs). Grizzly can be used to model the thermal/mechanical response of an RPV under transient conditions that would be observed in a pressurized thermal shock (PTS) scenario. The global response of the vessel provides boundary conditions for local models of the material in the vicinity of a flaw. Fracture domain integrals are computed to obtain stress intensity factors, which can in turn be used to assess whether a fracture would initiate at a pre-existing flaw. These capabilities have been demonstrated previously. A typical RPV is likely to contain a large population of pre-existing flaws introduced during the manufacturing process. This flaw population is characterized stastistically through probability density functions of the flaw distributions. The use of probabilistic techniques is necessary to assess the likelihood of crack initiation during a transient event. This report documents initial work to perform probabilistic analysis of RPV fracture during a PTS event using a combination of the RAVEN risk analysis code and Grizzly. This work is limited in scope, considering only a single flaw with deterministic geometry, but with uncertainty introduced in the parameters that influence fracture toughness. These results are benchmarked against equivalent models run in the FAVOR code. When fully developed, the RAVEN/Grizzly methodology for modeling probabilistic fracture in RPVs will provide a general capability that can be used to consider a wider variety of vessel and flaw conditions that are difficult to consider with current tools. In addition, this will provide access to advanced probabilistic techniques provided by RAVEN, including adaptive sampling and parallelism, which can dramatically

  18. Construction of two large-size four-plane micromegas detectors

    CERN Document Server

    Bianco, Michele; Degrange, Jordan; De Oliveira, Rui; Düdder, Andreas; Farina, Edoardo; Kuger, Fabian; Iengo, Paolo; Gomez, Francisco Perez; Lin, Tai-Hua; Schott, Matthias; Sekhniaidze, Givi; Sforza, Federico; Sidiropoulou, Ourania; Valderanis, Chrysostomos; Vergain, Maurice; Wotschack, Jörg

    2016-01-01

    We report on the construction and initial performance studies of two micromegas detector quadruplets with an area of 0.5 m$^2$. They serve as prototypes for the planned upgrade project of the ATLAS muon system. Their design is based on the resistive-strip technology and thus renders the detectors spark tolerant. Each quadruplet comprises four detection layers with 1024 readout strips and a strip pitch of 415 $\\mu$m. In two out of the four layers the strips are inclined by $\\pm$1.5$^{\\circ}$ to allow for the measurement of a second coordinate. We present the detector concept and report on the experience gained during the detector construction. In addition an evaluation of the detector performance with cosmic rays and test-beam data is given.

  19. Evaluation of quality improvement initiative in pediatric oncology: implementation of aggressive hydration protocol.

    Science.gov (United States)

    Fratino, Lisa M; Daniel, Denise A; Cohen, Kenneth J; Chen, Allen R

    2009-01-01

    Our goal was to improve the efficiency of chemotherapy administration for pediatric oncology patients. We identified prechemotherapy hydration as the process that most often delayed chemotherapy administration. An aggressive hydration protocol, supported by fluid order sets, was developed for patients receiving planned chemotherapy. The mean interval from admission to achieving adequate hydration status was reduced significantly from 4.9 to 1.4 hours with a minor reduction in the time to initiate chemotherapy from 9.6 to 8.6 hours. Chemotherapy availability became the new rate-limiting process.

  20. Site Specific Advisory Board initiative, evaluation survey results supplementary appendix: Summary of individual site results

    International Nuclear Information System (INIS)

    1996-08-01

    This Appendix presents results of the Site-Specific Advisory Board (SSAB) Initiative for each of the 11 sites that participated in the survey. These individual results are a supplement to the June 1996 Summary Report which presented overall survey results. Results are presented in 11 sections, arranged alphabetically by site. Each section includes a series of figures and tables that parallel those presented in the Summary Report. To facilitate comparison, figures are presented both for the individual site and for the overall long survey. The sequence of sections is: Fernald, Hanford, Idaho, Los Alamos, Monticello, Nevada, Pantex, Rocky Flats, St. Louis, Sandia, and Savannah River

  1. Enabling parents who smoke to prevent their children from initiating smoking: results from a 3-year intervention evaluation.

    Science.gov (United States)

    Jackson, Christine; Dickinson, Denise

    2006-01-01

    To evaluate effects of a home-based antismoking socialization program on the initiation of smoking among children whose parents smoke. Three-year randomized controlled trial. Parents who were current smokers and had a child in the third grade who had not tried smoking were eligible; 873 parents-offspring pairs met these criteria, completed baseline interviews, and were randomly assigned to the intervention or control condition; 776 children (89%) completed an interview 3 years after baseline and were included in the study. During 3 months, the intervention group (n = 371) received 5 printed activity guides, parenting tip sheets, child newsletters, and incentives; this group also received a booster activity guide 1 year later. The control group (n = 405) received fact sheets about smoking. Initiation of smoking (first instance of puffing on a cigarette) was reported by 12% vs 19% of children in the intervention vs control groups. Logistic regression analysis indicated that children in the control condition had twice the odds of reporting initiation of smoking as children in the intervention condition (adjusted odds ratio, 2.16; Pparent sex, parent race, parent educational achievement, child's best friends' smoking, parent smoking rate at baseline, and parent cessation status. Children in the pre-initiation phase of smoking who receive antismoking socialization from their parents are less likely to initiate smoking, even if their parents smoke.

  2. Receiver operating characteristics of diagnostic efficacy of resting left ventricular performance (evaluating with a non-imaging ECG gated scintillation detector - nuclear stethoscope)

    International Nuclear Information System (INIS)

    Kotlyarov, E.V.; Reba, R.C.; Lindsay, J.

    1983-01-01

    Receiver operating characteristic (ROC) analysis of left ventricular performance at rest was applied to evaluate diagnostic utility of non-imaging nuclear detector (''Nuclear Stethoscope''), for screening patients with coronary artery disease (CAD). Thirty-one patients without CAD and normal rest and stress radionuclide ventriculography (MUGA) were used as a contr