The scope of detector Medipix2 in micro-radiography of biological samples

International Nuclear Information System (INIS)

Dammer, J.; Weyda, F.; Jakubek, J.; Skrabal, P.; Sopko, V.; Vavrik, D.

2011-01-01

We present our experimental setup devoted to high resolution X-ray micro-radiography that is suitable for imaging of small biological samples. The photon source is a FeinFocus micro-focus X-ray tube. The single photon counting pixel device Medipix2 serves as imaging area. Recently used imaging detectors as radiography films or scintillator detectors, cannot visualize required information about inner structure of scanned sample. Detectors Medipix2 do not suffer from so-called dark current noise and work in unlimited dynamic range. These features of detectors confer high quality and high contrast of final images. The radiographic imaging with detectors Medipix2 represents non-invasive and non-destructive method of investigation. Hereby, we demonstrate results of micro-radiographic study of internal structures of tiny biological samples. In addition to morphological and anatomical studies, we would like to present preliminary study of dynamic processes inside of organisms using micro-radiographic video-capturing.

Calibration by precise charge injection of a sub-detector of CMS; Calibration par injection de charge du calorimetre electromagnetique de CMS

Energy Technology Data Exchange (ETDEWEB)

Yong-Wook Baek

2001-01-26

This thesis was carried out within the framework of the international collaboration which has the responsibility of the experience CMS (Compact Muon Solenoid) on LHC, at CERN. The physics of the fundamental particles which will be explored by this experiment is described within the standard model. The configuration of sub-detector of CMS is briefly described, with a particular weight on the read-out chain of the electromagnetic calorimeter. The work carried out to calibrate this chain by a precise charge injection at the input of preamplifiers is described. The 4 integrated circuits CTRL, TPLS, DAC, and injector which will constitute the components of this chain of calibration are described. The circuit of injection, which is the main circuit in this project, was imagined and developed at the laboratory in DMILL technology. This injector generates a signal which has a form identical to the signal of the detector. The measurements on the linearity of the injectors are presented. In order to know its behavior under real conditions (flow of neutrons {approx} 2 x 10{sup 13} neutrons/cm{sup 2}/10 years) where this circuit is installed in detector CMS, we submitted the prototypes of injector to irradiation and the results are summarized. The research and development on this circuit produced an integrated circuit hardened to irradiations, whose variation of slope is lower than 0.25% for an integrated of 2 x 10{sup 13} neutrons/cm{sup 2} and indestructible under 10{sup 15} neutrons/cm{sup 2}. This circuit has satisfactory qualities to be assembled on the electronic card which will treat the data of calorimeter ECAL of CMS. (author)

Radiometric flow injection analysis with an ASIA (Ismatec) analyzer

Energy Technology Data Exchange (ETDEWEB)

Myint, U; Win, N; San, K; Han, B; Myoe, K M [Yangon Univ. (Myanmar). Dept. of Chemistry; Toelgyessy, J [Slovak Technical Univ., Bratislava (Slovakia). Dept. of Environmental Science

1994-07-01

Radiometric Flow Injection Analysis of a radioactive ([sup 131]I) sample is described. For analysis an ASIA (Ismatec) analyzer with a NaI(Tl) scintillation detector was used. (author) 5 refs.; 3 figs.

Trends and perspectives of flow injection/sequential injection on-line sample-pretreatment schemes coupled to ETAAS

DEFF Research Database (Denmark)

Wang, Jianhua; Hansen, Elo Harald

2005-01-01

Flow injection (FI) analysis, the first generation of this technique, became in the 1990s supplemented by its second generation, sequential injection (SI), and most recently by the third generation (i.e.,Lab-on-Valve). The dominant role played by FI in automatic, on-line, sample pretreatments in ...

Particle identification using digital pulse shape discrimination in a nTD silicon detector with a 1 GHz sampling digitizer

Science.gov (United States)

Mahata, K.; Shrivastava, A.; Gore, J. A.; Pandit, S. K.; Parkar, V. V.; Ramachandran, K.; Kumar, A.; Gupta, S.; Patale, P.

2018-06-01

In beam test experiments have been carried out for particle identification using digital pulse shape analysis in a 500 μm thick Neutron Transmutation Doped (nTD) silicon detector with an indigenously developed FPGA based 12 bit resolution, 1 GHz sampling digitizer. The nTD Si detector was used in a low-field injection setup to detect light heavy-ions produced in reactions of ∼ 5 MeV/A 7Li and 12C beams on different targets. Pulse height, rise time and current maximum have been obtained from the digitized charge output of a high bandwidth charge and current sensitive pre-amplifier. Good isotopic separation have been achieved using only the digitized charge output in case of light heavy-ions. The setup can be used for charged particle spectroscopy in nuclear reactions involving light heavy-ions around the Coulomb barrier energies.

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

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

Application of direct-injection detector integrated with the multi-pumping flow system to chemiluminescence determination of the total polyphenol index.

Science.gov (United States)

Nalewajko-Sieliwoniuk, Edyta; Iwanowicz, Magdalena; Kalinowski, Sławomir; Kojło, Anatol

2016-03-10

In this work, we present a novel chemiluminescence (CL) method based on direct-injection detector (DID) integrated with the multi-pumping flow system (MPFS) to chemiluminescence determination of the total polyphenol index. In this flow system, the sample and the reagents are injected directly into the cone-shaped detection cell placed in front of the photomultiplier window. Such construction of the detection chamber allows for fast measurement of the CL signal in stopped-flow conditions immediately after mixing the reagents. The proposed DID-CL-MPFS method is based on the chemiluminescence of nanocolloidal manganese(IV)-hexametaphosphate-ethanol system. The application of ethanol as a sensitizer, eliminated the use of carcinogenic formaldehyde. Under the optimized experimental conditions, the chemiluminescence intensities are proportional to the concentration of gallic acid in the range from 5 to 350 ng mL(-1). The DID-CL-MPFS method offers a number of advantages, including low limit of detection (0.80 ng mL(-1)), high precision (RSD = 3.3%) and high sample throughput (144 samples h(-1)) as well as low consumption of reagents, energy and low waste generation. The proposed method has been successfully applied to determine the total polyphenol index (expressed as gallic acid equivalent) in a variety of plant-derived food samples (wine, tea, coffee, fruit and vegetable juices, herbs, spices). Copyright © 2016 Elsevier B.V. All rights reserved.

Sample dependent response of a LaCl{sub 3}:Ce detector in prompt gamma neutron activation analysis of bulk hydrocarbon samples

Energy Technology Data Exchange (ETDEWEB)

Naqvi, A.A., E-mail: aanaqvi@kfupm.edu.sa [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Al-Matouq, Faris A.; Khiari, F.Z. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Isab, A.A. [Department of Chemistry, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Khateeb-ur-Rehman,; Raashid, M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

2013-08-11

The response of a LaCl{sub 3}:Ce detector has been found to depend upon the hydrogen content of bulk samples in prompt gamma analysis using 14 MeV neutron inelastic scattering. The moderation of 14 MeV neutrons from hydrogen in the bulk sample produces thermal neutrons around the sample which ultimately excite chlorine capture gamma rays in the LaCl{sub 3}:Ce detector material. Interference of 6.11 MeV chlorine gamma rays from the detector itself with 6.13 MeV oxygen gamma rays from the bulk samples makes the intensity of the 6.13 MeV oxygen gamma ray peak relatively insensitive to variations in oxygen concentration. The strong dependence of the 1.95 MeV doublet chlorine gamma ray yield on hydrogen content of the bulk samples confirms fast neutron moderation from hydrogen in the bulk samples as a major source of production of thermal neutrons and chlorine gamma rays in the LaCl{sub 3}:Ce detector material. Despite their poor oxygen detection capabilities, these detectors have nonetheless excellent detection capabilities for hydrogen and carbon in benzene, butyl alcohol, propanol, propanic acid, and formic acid bulk samples using 14 MeV neutron inelastic scattering.

Simulation study of signal formation in position sensitive planar p-on-n silicon detectors after short range charge injection

International Nuclear Information System (INIS)

Peltola, T.; Eremin, V.; Verbitskaya, E.; Härkönen, J.

2017-01-01

Segmented silicon detectors (micropixel and microstrip) are the main type of detectors used in the inner trackers of Large Hadron Collider (LHC) experiments at CERN. Due to the high luminosity and eventual high fluence of energetic particles, detectors with fast response to fit the short shaping time of 20–25 ns and sufficient radiation hardness are required. Charge collection measurements carried out at the Ioffe Institute have shown a reversal of the pulse polarity in the detector response to short-range charge injection. Since the measured negative signal is about 30–60% of the peak positive signal, the effect strongly reduces the CCE even in non-irradiated detectors. For further investigation of the phenomenon the measurements have been reproduced by TCAD simulations. As for the measurements, the simulation study was applied for the p-on-n strip detectors similar in geometry to those developed for the ATLAS experiment and for the Ioffe Institute designed p-on-n strip detectors with each strip having a window in the metallization covering the p + implant, allowing the generation of electron-hole pairs under the strip implant. Red laser scans across the strips and the interstrip gap with varying laser diameters and Si-SiO 2 interface charge densities ( Q f ) were carried out. The results verify the experimentally observed negative response along the scan in the interstrip gap. When the laser spot is positioned on the strip p + implant the negative response vanishes and the collected charge at the active strip increases respectively. The simulation results offer a further insight and understanding of the influence of the oxide charge density in the signal formation. The main result of the study is that a threshold value of Q f , that enables negligible losses of collected charges, is defined. The observed effects and details of the detector response for different charge injection positions are discussed in the context of Ramo's theorem.

Simulation study of signal formation in position sensitive planar p-on-n silicon detectors after short range charge injection

Science.gov (United States)

Peltola, T.; Eremin, V.; Verbitskaya, E.; Härkönen, J.

2017-09-01

Segmented silicon detectors (micropixel and microstrip) are the main type of detectors used in the inner trackers of Large Hadron Collider (LHC) experiments at CERN. Due to the high luminosity and eventual high fluence of energetic particles, detectors with fast response to fit the short shaping time of 20-25 ns and sufficient radiation hardness are required. Charge collection measurements carried out at the Ioffe Institute have shown a reversal of the pulse polarity in the detector response to short-range charge injection. Since the measured negative signal is about 30-60% of the peak positive signal, the effect strongly reduces the CCE even in non-irradiated detectors. For further investigation of the phenomenon the measurements have been reproduced by TCAD simulations. As for the measurements, the simulation study was applied for the p-on-n strip detectors similar in geometry to those developed for the ATLAS experiment and for the Ioffe Institute designed p-on-n strip detectors with each strip having a window in the metallization covering the p+ implant, allowing the generation of electron-hole pairs under the strip implant. Red laser scans across the strips and the interstrip gap with varying laser diameters and Si-SiO2 interface charge densities (Qf) were carried out. The results verify the experimentally observed negative response along the scan in the interstrip gap. When the laser spot is positioned on the strip p+ implant the negative response vanishes and the collected charge at the active strip increases respectively. The simulation results offer a further insight and understanding of the influence of the oxide charge density in the signal formation. The main result of the study is that a threshold value of Qf, that enables negligible losses of collected charges, is defined. The observed effects and details of the detector response for different charge injection positions are discussed in the context of Ramo's theorem.

Simultaneous Determination of Iron, Copper and Cobalt in Food Samples by CCD-diode Array Detection-Flow Injection Analysis with Partial Least Squares Calibration Model

International Nuclear Information System (INIS)

Mi Jiaping; Li Yuanqian; Zhou Xiaoli; Zheng Bo; Zhou Ying

2006-01-01

A flow injection-CCD diode array detection spectrophotometry with partial least squares (PLS) program for simultaneous determination of iron, copper and cobalt in food samples has been established. The method was based on the chromogenic reaction of the three metal ions and 2- (5-Bromo-2-pyridylazo)-5-diethylaminophenol, 5-Br-PADAP in acetic acid - sodium acetate buffer solution (pH5) with Triton X-100 and ascorbic acid. The overlapped spectra of the colored complexes were collected by charge-coupled device (CCD) - diode array detector and the multi-wavelength absorbance data was processed using partial least squares (PLS) algorithm. Optimum reaction conditions and parameters of flow injection analysis were investigated. The samples of tea, sesame, laver, millet, cornmeal, mung bean and soybean powder were determined by the proposed method. The average recoveries of spiked samples were 91.80%∼100.9% for Iron, 92.50%∼108.0% for Copper, 93.00%∼110.5% for Cobalt, respectively with relative standard deviation (R.S.D) of 1.1%∼12.1%. The sampling rate is 45 samples h -1 . The determination results of the food samples were in good agreement between the proposed method and ICP-AES

Simultaneous Determination of Iron, Copper and Cobalt in Food Samples by CCD-diode Array Detection-Flow Injection Analysis with Partial Least Squares Calibration Model

Energy Technology Data Exchange (ETDEWEB)

Mi Jiaping; Li Yuanqian; Zhou Xiaoli; Zheng Bo; Zhou Ying [West China School of Public Health, Sichuan University, Chengdu, 610041 (China)

2006-01-01

A flow injection-CCD diode array detection spectrophotometry with partial least squares (PLS) program for simultaneous determination of iron, copper and cobalt in food samples has been established. The method was based on the chromogenic reaction of the three metal ions and 2- (5-Bromo-2-pyridylazo)-5-diethylaminophenol, 5-Br-PADAP in acetic acid - sodium acetate buffer solution (pH5) with Triton X-100 and ascorbic acid. The overlapped spectra of the colored complexes were collected by charge-coupled device (CCD) - diode array detector and the multi-wavelength absorbance data was processed using partial least squares (PLS) algorithm. Optimum reaction conditions and parameters of flow injection analysis were investigated. The samples of tea, sesame, laver, millet, cornmeal, mung bean and soybean powder were determined by the proposed method. The average recoveries of spiked samples were 91.80%{approx}100.9% for Iron, 92.50%{approx}108.0% for Copper, 93.00%{approx}110.5% for Cobalt, respectively with relative standard deviation (R.S.D) of 1.1%{approx}12.1%. The sampling rate is 45 samples h{sup -1}. The determination results of the food samples were in good agreement between the proposed method and ICP-AES.

Simultaneous Determination of Iron, Copper and Cobalt in Food Samples by CCD-diode Array Detection-Flow Injection Analysis with Partial Least Squares Calibration Model

Science.gov (United States)

Mi, Jiaping; Li, Yuanqian; Zhou, Xiaoli; Zheng, Bo; Zhou, Ying

2006-01-01

A flow injection-CCD diode array detection spectrophotometry with partial least squares (PLS) program for simultaneous determination of iron, copper and cobalt in food samples has been established. The method was based on the chromogenic reaction of the three metal ions and 2- (5-Bromo-2-pyridylazo)-5-diethylaminophenol, 5-Br-PADAP in acetic acid - sodium acetate buffer solution (pH5) with Triton X-100 and ascorbic acid. The overlapped spectra of the colored complexes were collected by charge-coupled device (CCD) - diode array detector and the multi-wavelength absorbance data was processed using partial least squares (PLS) algorithm. Optimum reaction conditions and parameters of flow injection analysis were investigated. The samples of tea, sesame, laver, millet, cornmeal, mung bean and soybean powder were determined by the proposed method. The average recoveries of spiked samples were 91.80%~100.9% for Iron, 92.50%~108.0% for Copper, 93.00%~110.5% for Cobalt, respectively with relative standard deviation (R.S.D) of 1.1%~12.1%. The sampling rate is 45 samples h-1. The determination results of the food samples were in good agreement between the proposed method and ICP-AES.

Calibration of track detectors and measurement of radon exhalation rate from solid samples

International Nuclear Information System (INIS)

Singh, Ajay Kumar; Jojo, P.J.; Prasad, Rajendra; Khan, A.J.; Ramachandran, T.V.

1997-01-01

CR-39 and LR-115 type II track detectors to be used for radon exhalation measurements have been calibrated. The configurations fitted with detectors in Can technique in the open cup mode are cylindrical plastic cup (PC) and conical plastic cup (CPC). The experiment was performed in radon exposure chamber having monodisperse aerosols of 0.2 μm size, to find the relationship between track density and the radon concentration. The calibration factors for PC and CPC type dosimeters with LR-115 type II detector were found to be 0.056 and 0.083 tracks cm -2 d -1 (Bqm -3 ) -1 respectively, while with CR-39 detector the values were 0.149 and 0.150 tracks cm -2 d -1 (Bq m -3 ) -1 . Employing the Can technique, measurements of exhalation rates from solid samples used as construction materials, are undertaken. Radon exhalation rate is found to be minimum in cement samples while in fly ash it is not enhanced as compared to coal samples. (author)

Application of digital sampling techniques to particle identification in scintillation detectors

International Nuclear Information System (INIS)

Bardelli, L.; Bini, M.; Poggi, G.; Taccetti, N.

2002-01-01

In this paper, the use of a fast digitizing system for identification of fast charged particles with scintillation detectors is discussed. The three-layer phoswich detectors developed in the framework of the FIASCO experiment for the detection of light charged particles (LCP) and intermediate mass fragments (IMF) emitted in heavy-ion collisions at Fermi energies are briefly discussed. The standard analog electronics treatment of the signals for particle identification is illustrated. After a description of the digitizer designed to perform a fast digital sampling of the phoswich signals, the feasibility of particle identification on the sampled data is demonstrated. The results obtained with two different pulse shape discrimination analyses based on the digitally sampled data are compared with the standard analog signal treatment. The obtained results suggest, for the present application, the replacement of the analog methods with the digital sampling technique

Sample and injection manifolds used to in-place test of nuclear air-cleaning system

International Nuclear Information System (INIS)

Qiu Dangui; Li Xinzhi; Hou Jianrong; Qiao Taifei; Wu Tao; Zhang Jirong; Han Lihong

2012-01-01

Objective: According to the regulations of nuclear safety rules and related standards, in-place test of the nuclear air-cleaning systems should be carried out before and during operation of the nuclear facilities, which ensure them to be in good condition. In some special conditions, the use of sample and injection manifolds is required to make the test tracer and ventilating duct air fully mixed, so as to get the on-spot typical sample. Methods: This paper introduces the technology and application of the sample and injection manifolds in nuclear air-cleaning system. Results: Multi point injection and multi point sampling technology as an effective experimental method, has been used in a of domestic and international nuclear facilities. Conclusion: The technology solved the problem of uniformly of on-spot injection and sampling,which plays an important role in objectively evaluating the function of nuclear air-cleaning system. (authors)

A miniature silicon diode matrix detector for in vivo measurement of 133Xe disappearance following local tissue injection

DEFF Research Database (Denmark)

Bendtsen, K; Svendsen, Jesper Hastrup; Rasmussen, H B

1992-01-01

have the capability of measuring the lowest energies (25-40 keV) of gamma and x-ray emitters with sufficient efficiency when applied on the skin surface and close to the indicator depot. The purpose of the present study was firstly to evaluate a portable Si photodiode matrix detector system, composed...... and sensitivity within the range 20-38 degrees C and calibrated to +/- 1% between diodes. The in vivo investigations comprised two SC injections on humans with four measuring periods for comparison, and four SC and five SM injections on dogs, resulting in eight and five measuring periods for comparison. Only when...

Optimization of the two-sample rank Neyman-Pearson detector

Science.gov (United States)

Akimov, P. S.; Barashkov, V. M.

1984-10-01

The development of optimal algorithms concerned with rank considerations in the case of finite sample sizes involves considerable mathematical difficulties. The present investigation provides results related to the design and the analysis of an optimal rank detector based on a utilization of the Neyman-Pearson criteria. The detection of a signal in the presence of background noise is considered, taking into account n observations (readings) x1, x2, ... xn in the experimental communications channel. The computation of the value of the rank of an observation is calculated on the basis of relations between x and the variable y, representing interference. Attention is given to conditions in the absence of a signal, the probability of the detection of an arriving signal, details regarding the utilization of the Neyman-Pearson criteria, the scheme of an optimal rank, multichannel, incoherent detector, and an analysis of the detector.

Radiation tolerance studies using fault injection on the Readout Control FPGA design of the ALICE TPC detector

Science.gov (United States)

Alme, J.; Fehlker, D.; Lippmann, C.; Mager, M.; Rehman, A. U.; Røed, K.; Röhrich, D.; Ullaland, K.

2013-01-01

Single Event Upsets (SEUs) are a major concern for the TPC Readout Control Unit (RCU) of the ALICE experiment. A SEU is defined as a radiation related bit-flip in a memory cell, and a SEU in the onboard SRAM based FPGA of the RCU may lead to corrupted data or, even worse, a system malfunction. The latter situation will affect the operation of the ALICE detector since it causes a premature end of data taking. Active partial reconfiguration is utilized in a dedicated reconfiguration solution on the RCU, and this makes it possible to implement fault injection. Fault injection means inserting bit flips in the configuration memory of the FPGA in a controlled laboratory environment. This paper presents the results of the fault injection study and shows how this result can be combined with SEU measurements to estimate the functional failure rate as a function of luminosity.

Method of quantitative analysis of fluorine in environmental samples using a pure-Ge detector

International Nuclear Information System (INIS)

Sera, K.; Terasaki, K.; Saitoh, Y.; Itoh, J.; Futatsugawa, S.; Murao, S.; Sakurai, S.

2004-01-01

We recently developed and reported a three-detector measuring system making use of a pure-Ge detector combined with two Si(Li) detectors. The efficiency curve of the pure-Ge detector was determined as relative efficiencies to those of the existing Si(Li) detectors and accuracy of it was confirmed by analyzing a few samples whose elemental concentrations were known. It was found that detection of fluorine becomes possible by analyzing prompt γ-rays and the detection limit was found to be less than 0.1 ppm for water samples. In this work, a method of quantitative analysis of fluorine has been established in order to investigate environmental contamination by fluorine. This method is based on the fact that both characteristic x-rays from many elements and 110 keV prompt γ-rays from fluorine can be detected in the same spectrum. The present method is applied to analyses of a few environmental samples such as tealeaves, feed for domestic animals and human bone. The results are consistent with those obtained by other methods and it is found that the present method is quite useful and convenient for investigation studies on regional pollution by fluorine. (author)

Two specialized delayed-neutron detector designs for assays of fissionable elements in water and sediment samples

International Nuclear Information System (INIS)

Balestrini, S.J.; Balagna, J.P.; Menlove, H.O.

1976-01-01

Two specialized neutron-sensitive detectors are described which are employed for rapid assays of fissionable elements by sensing for delayed neutrons emitted by samples after they have been irradiated in a nuclear reactor. The more sensitive of the two detectors, designed to assay for uranium in water samples, is 40% efficient; the other, designed for sediment sample assays, is 27% efficient. These detectors are also designed to operate under water as an inexpensive shielding against neutron leakage from the reactor and neutrons from cosmic rays. (Auth.)

Automated injection of a radioactive sample for preparative HPLC with feedback control

International Nuclear Information System (INIS)

Iwata, Ren; Yamazaki, Shigeki

1990-01-01

The injection of a radioactive reaction mixture into a preparative HPLC column has been automated with computer control for rapid purification of routinely prepared positron emitting radiopharmaceuticals. Using pneumatic valves, a motor-driven pump and a liquid level sensor, two intelligent injection methods for the automation were compared with regard to efficient and rapid sample loading into a 2 mL loop of the 6-way valve. One, a precise but rather slow method, was demonstrated to be suitable for purification of 18 F-radiopharmaceuticals, while the other, due to its rapid operation, was more suitable for 11 C-radiopharmaceuticals. A sample volume of approx 0.5 mL can be injected onto a preparative HPLC column with over 90% efficiency with the present automated system. (author)

Si(Li)-NaI(Tl) sandwich detector array for measurements of trace radionuclides in soil samples

International Nuclear Information System (INIS)

Strauss, M.G.; Sherman, I.S.; Roche, C.T.; Pehl, R.H.

1986-01-01

An ultra-sensitive X/γ-ray detector system for assaying trace radioactivity in actinide contaminated soil and ash samples has been developed. The new system consists of an array of 6 large Si(Li) X-ray detectors sensitive on both faces and mounted on edge in a paddle-shaped cryostat with a 14 cm diameter Be window on each side. The paddle, with a sample of the soil placed at each window, is sandwiched between 2 large NaI(Tl) scintillators which suppress the γ background. With X-rays being measured simultaneously from soil in 2 sample holders and background reduced by 50% using anticoincidence, the sensitivity of this detector is 4 times higher than that of conventionally mounted Si(Li) detectors. A soil sample containing 50 pCi/g 239 Pu was measured in 5 min with an uncertainty of 1 and NpLsub(β1) X-ray peaks are resolved thus permitting measurement of trace Pu in the presence of 241 Am. This is the most sensitive and selective detector known for nondestructive assay of radioactivity in soil and other samples. (orig.)

Wideband and high-gain frequency stabilization of a 100-W injection-locked Nd:YAG laser for second-generation gravitational wave detectors.

Science.gov (United States)

Ohmae, Noriaki; Moriwaki, Shigenori; Mio, Norikatsu

2010-07-01

Second-generation gravitational wave detectors require a highly stable laser with an output power greater than 100 W to attain their target sensitivity. We have developed a frequency stabilization system for a 100-W injection-locked Nd:YAG (yttrium aluminum garnet) laser. By placing an external wideband electro-optic modulator used as a fast-frequency actuator in the optical path of the slave output, we can circumvent a phase delay in the frequency control loop originating from the pole of an injection-locked slave cavity. Thus, we have developed an electro-optic modulator made of a MgO-doped stoichiometric LiNbO(3) crystal. Using this modulator, we achieve a frequency control bandwidth of 800 kHz and a control gain of 180 dB at 1 kHz. These values satisfy the requirement for a laser frequency control loop in second-generation gravitational wave detectors.

Detectors on Edge Nodes against False Data Injection on Transmission Lines of Smart Grid

Directory of Open Access Journals (Sweden)

Peng Xun

2018-06-01

Full Text Available False data injection (FDI attack is a hot topic in large-scale Cyber-Physical Systems (CPSs, which can cause bad state estimation of controllers. In this paper, we focus on FDI detection on transmission lines of the smart grid. We propose a novel and effective detection framework to identify FDI attacks. Different from the previous methods, there are multi-tier detectors which utilize edge nodes such as the programmable logic controllers (PLCs instead of the central controller to detect attacks. The proposed framework can decrease the transmission time of data to reduce the latency of decisions because many sensory data need not be transmitted to the central controller for detection. We also develop a detection algorithm which utilizes classifiers based on machine learning to identify FDI. The training process is split from every edge node and is placed on the central node. The detectors are lightweight and are properly adopted in our detection framework. Our simulation experiments show that the proposed detection framework can provide better detection results than the existing detection approaches.

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...

Laser solid sampling for a solid-state-detector ICP emission spectrometer

International Nuclear Information System (INIS)

Noelte, J.; Moenke-Blankenburg, L.; Schumann, T.

1994-01-01

Solid sampling with laser vaporization has been coupled to an ICP emission spectrometer with an Echelle optical system and a solid-state-detector for the analysis of steel and soil samples. Pulsation of the vaporized material flow was compensated by real-time background correction and internal standardization, resulting in good accuracy and precision. (orig.)

An enzymatic method for the rapid measurement of the hemoglobin A1c by a flow-injection system comprised of an electrochemical detector with a specific enzyme-reactor and a spectrophotometer

International Nuclear Information System (INIS)

Nanjo, Yoko; Hayashi, Ryuzo; Yao, Toshio

2007-01-01

A flow-injection analytical (FIA) system, comprised of an electrochemical detector with a fructosyl-peptide oxidase (FPOX-CET) reactor and a flow-type spectrophotometer, was proposed for the simultaneous measurement of glycohemoglobin and total hemoglobin in blood cell. The blood cell samples were hemolyzed with a surfactant and then treated with protease. In the first stage of operation, total hemoglobin in digested sample was determined spectrophotometrically. In the second stage, fructosyl valyl histidine (FVH) released from glycohemoglobin by the selective proteolysis was determined specifically using the electrochemical detector with the FPOX-CET reactor. The FIA system could be automatically processed at an analytical speed of 40 samples per hour. The proposed assay method could determine selectively only the glycated N-terminal residue of β-chain in glycohemoglobin and total hemoglobin in blood cell. The enzymatic hemoglobin A 1c (HbA 1c ) value calculated by the concentration ratio of the FVH to total hemoglobin, was closely correlated with the HbA 1c values certified by the Japan Diabetic Society (JDS) and the International Federation of Clinical Chemistry (IFCC)

Use of a new ion-detector in the study of the jet plasma injected into a pulsed magnetic mirror configuration (deca I)

International Nuclear Information System (INIS)

Renaud, C.

1963-01-01

The study of a high sensitivity ion detector coupled to an electrostatic analyser has permitted a large investigation of the plasma jet injected into a pulsed magnetic mirror configuration. In this detector the positive ions are accelerated through a potential of 30 kV; they strike a metallic target, on which they produce secondary electrons; these, in turn, are accelerated onto a plastic scintillator. The light pulses are detected with a photomultiplier. The gain of this device is about 10 7 . If we make an admission of air into the vacuum system and again we make vacuum, the gain is not modified, since no special activated surfaces are situated in the detector. (author) [fr

Matching Ge detector element geometry to sample size and shape: One does not fit all exclamation point

International Nuclear Information System (INIS)

Keyser, R.M.; Twomey, T.R.; Sangsingkeow, P.

1998-01-01

For 25 yr, coaxial germanium detector performance has been specified using the methods and values specified in Ref. 1. These specifications are the full-width at half-maximum (FWHM), FW.1M, FW.02M, peak-to-Compton ratio, and relative efficiency. All of these measurements are made with a 60 Co source 25 cm from the cryostat endcap and centered on the axis of the detector. These measurements are easy to reproduce, both because they are simple to set up and use a common source. These standard tests have been useful in guiding the user to an appropriate detector choice for the intended measurement. Most users of germanium gamma-ray detectors do not make measurements in this simple geometry. Germanium detector manufacturers have worked over the years to make detectors with better resolution, better peak-to-Compton ratios, and higher efficiency--but all based on measurements using the IEEE standard. Advances in germanium crystal growth techniques have made it relatively easy to provide detector elements of different shapes and sizes. Many of these different shapes and sizes can give better results for a specific application than other shapes and sizes. But, the detector specifications must be changed to correspond to the actual application. Both the expected values and the actual parameters to be specified should be changed. In many cases, detection efficiency, peak shape, and minimum detectable limit for a particular detector/sample combination are valuable specifications of detector performance. For other situations, other parameters are important, such as peak shape as a function of count rate. In this work, different sample geometries were considered. The results show the variation in efficiency with energy for all of these sample and detector geometries. The point source at 25 cm from the endcap measurement allows the results to be compared with the currently given IEEE criteria. The best sample/detector configuration for a specific measurement requires more and

Determination of trihalomethanes in water samples: A review

Energy Technology Data Exchange (ETDEWEB)

Perez Pavon, Jose Luis [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias Quimicas, Universidad de Salamanca, 37008 Salamanca (Spain)], E-mail: jlpp@usal.es; Herrero Martin, Sara; Garcia Pinto, Carmelo; Moreno Cordero, Bernardo [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias Quimicas, Universidad de Salamanca, 37008 Salamanca (Spain)

2008-11-23

This article reviews the most recent literature addressing the analytical methods applied for trihalomethanes (THMs) determination in water samples. This analysis is usually performed with gas chromatography (GC) combined with a preconcentration step. The detectors most widely used in this type of analyses are mass spectrometers (MS) and electron capture detectors (ECD). Here, we review the analytical characteristics, the time required for analysis, and the simplicity of the optimised methods. The main difference between these methods lies in the sample pretreatment step; therefore, special emphasis is placed on this aspect. The techniques covered are direct aqueous injection (DAI), liquid-liquid extraction (LLE), headspace (HS), and membrane-based techniques. We also review the main chromatographic columns employed and consider novel aspects of chromatographic analysis, such as the use of fast gas chromatography (FGC). Concerning the detection step, besides the common techniques, the use of uncommon detectors such as fluorescence detector, pulsed discharge photoionization detector (PDPID), dry electrolytic conductivity detector (DELCD), atomic emission detector (AED) and inductively coupled plasma-mass spectrometry (ICP-MS) for this type of analysis is described.

Solid reactors in sequential injection analysis: Recent trends in the environmental field

DEFF Research Database (Denmark)

Miró, Manuel; Hansen, Elo Harald

2006-01-01

-bead injection (SI-BI), used in either the jet-ring or lab-on-valve configurations, is presented as a front-end to many detectors. This article also outlines recent trends focused on exploiting SI as an automated tool for handling solid samples of environmental concern and accommodating dynamic fractionation...

Influence of high-conductivity buffer composition on field-enhanced sample injection coupled to sweeping in CE.

Science.gov (United States)

Anres, Philippe; Delaunay, Nathalie; Vial, Jérôme; Thormann, Wolfgang; Gareil, Pierre

2013-02-01

The aim of this work was to clarify the mechanism taking place in field-enhanced sample injection coupled to sweeping and micellar EKC (FESI-Sweep-MEKC), with the utilization of two acidic high-conductivity buffers (HCBs), phosphoric acid or sodium phosphate buffer, in view of maximizing sensitivity enhancements. Using cationic model compounds in acidic media, a chemometric approach and simulations with SIMUL5 were implemented. Experimental design first enabled to identify the significant factors and their potential interactions. Simulation demonstrates the formation of moving boundaries during sample injection, which originate at the initial sample/HCB and HCB/buffer discontinuities and gradually change the compositions of HCB and BGE. With sodium phosphate buffer, the HCB conductivity increased during the injection, leading to a more efficient preconcentration by staking (about 1.6 times) than with phosphoric acid alone, for which conductivity decreased during injection. For the same injection time at constant voltage, however, a lower amount of analytes was injected with sodium phosphate buffer than with phosphoric acid. Consequently sensitivity enhancements were lower for the whole FESI-Sweep-MEKC process. This is why, in order to maximize sensitivity enhancements, it is proposed to work with sodium phosphate buffer as HCB and to use constant current during sample injection. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Differences in microbial community composition between injection and production water samples of water flooding petroleum reservoirs

Directory of Open Access Journals (Sweden)

P. K. Gao

2015-06-01

Full Text Available Microbial communities in injected water are expected to have significant influence on those of reservoir strata in long-term water flooding petroleum reservoirs. To investigate the similarities and differences in microbial communities in injected water and reservoir strata, high-throughput sequencing of microbial partial 16S rRNA of the water samples collected from the wellhead and downhole of injection wells, and from production wells in a homogeneous sandstone reservoir and a heterogeneous conglomerate reservoir were performed. The results indicate that a small number of microbial populations are shared between the water samples from the injection and production wells in the sandstone reservoir, whereas a large number of microbial populations are shared in the conglomerate reservoir. The bacterial and archaeal communities in the reservoir strata have high concentrations, which are similar to those in the injected water. However, microbial population abundance exhibited large differences between the water samples from the injection and production wells. The number of shared populations reflects the influence of microbial communities in injected water on those in reservoir strata to some extent, and show strong association with the unique variation of reservoir environments.

A simulation study of high-resolution x-ray computed tomography imaging using irregular sampling with a photon-counting detector

International Nuclear Information System (INIS)

Lee, Seungwan; Choi, Yu-Na; Kim, Hee-Joung

2013-01-01

The purpose of this study was to improve the spatial resolution for the x-ray computed tomography (CT) imaging with a photon-counting detector using an irregular sampling method. The geometric shift-model of detector was proposed to produce the irregular sampling pattern and increase the number of samplings in the radial direction. The conventional micro-x-ray CT system and the novel system with the geometric shift-model of detector were simulated using analytic and Monte Carlo simulations. The projections were reconstructed using filtered back-projection (FBP), algebraic reconstruction technique (ART), and total variation (TV) minimization algorithms, and the reconstructed images were compared in terms of normalized root-mean-square error (NRMSE), full-width at half-maximum (FWHM), and coefficient-of-variation (COV). The results showed that the image quality improved in the novel system with the geometric shift-model of detector, and the NRMSE, FWHM, and COV were lower for the images reconstructed using the TV minimization technique in the novel system with the geometric shift-model of detector. The irregular sampling method produced by the geometric shift-model of detector can improve the spatial resolution and reduce artifacts and noise for reconstructed images obtained from an x-ray CT system with a photon-counting detector. -- Highlights: • We proposed a novel sampling method based on a spiral pattern to improve the spatial resolution. • The novel sampling method increased the number of samplings in the radial direction. • The spatial resolution was improved by the novel sampling method

Multiagency Urban Search Experiment Detector and Algorithm Test Bed

Science.gov (United States)

Nicholson, Andrew D.; Garishvili, Irakli; Peplow, Douglas E.; Archer, Daniel E.; Ray, William R.; Swinney, Mathew W.; Willis, Michael J.; Davidson, Gregory G.; Cleveland, Steven L.; Patton, Bruce W.; Hornback, Donald E.; Peltz, James J.; McLean, M. S. Lance; Plionis, Alexander A.; Quiter, Brian J.; Bandstra, Mark S.

2017-07-01

In order to provide benchmark data sets for radiation detector and algorithm development, a particle transport test bed has been created using experimental data as model input and validation. A detailed radiation measurement campaign at the Combined Arms Collective Training Facility in Fort Indiantown Gap, PA (FTIG), USA, provides sample background radiation levels for a variety of materials present at the site (including cinder block, gravel, asphalt, and soil) using long dwell high-purity germanium (HPGe) measurements. In addition, detailed light detection and ranging data and ground-truth measurements inform model geometry. This paper describes the collected data and the application of these data to create background and injected source synthetic data for an arbitrary gamma-ray detection system using particle transport model detector response calculations and statistical sampling. In the methodology presented here, HPGe measurements inform model source terms while detector response calculations are validated via long dwell measurements using 2"×4"×16" NaI(Tl) detectors at a variety of measurement points. A collection of responses, along with sampling methods and interpolation, can be used to create data sets to gauge radiation detector and algorithm (including detection, identification, and localization) performance under a variety of scenarios. Data collected at the FTIG site are available for query, filtering, visualization, and download at muse.lbl.gov.

Calibration of diffusion barrier charcoal detectors and application to radon sampling in dwellings

International Nuclear Information System (INIS)

Montero C, M.E.; Colmenero S, L.; Villalba, L.; Saenz P, J.; Cano J, A.; Moreno B, A.; Renteria V, M.; Herrera P, E.F.; Cruz G, S. De la; Lopez M, A.

2003-01-01

Some calibration conditions of diffusion barrier charcoal canister (DBCC) detectors for measuring radon concentration in air were studied. A series of functional expressions and graphs were developed to describe relationship between radon concentration in air and the activity adsorbed in DBCC, when placed in small chambers. A semi-empirical expression for the DBCC calibration was obtained, based on the detector integration time and the adsorption coefficient of radon on activated charcoal. Both, the integration time for 10 % of DBCC of the same batch, and the adsorption coefficient of radon for the activated charcoal used in these detectors, were experimentally determined. Using these values as the calibration parameters, a semi-empirical calibration function was used for the interpretation of the radon activities in the detectors used for sampling more than 200 dwellings in the major cities of the state of Chihuahua, Mexico. (Author)

Calibration of diffusion barrier charcoal detectors and application to radon sampling in dwellings

Energy Technology Data Exchange (ETDEWEB)

Montero C, M.E.; Colmenero S, L.; Villalba, L.; Saenz P, J.; Cano J, A.; Moreno B, A.; Renteria V, M.; Herrera P, E.F. [Cento de Investigacion en Materiales Avanzados, S. C. Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua, (Mexico); Cruz G, S. De la [Facultad de Enfermeria y Nutriologia, Universidad Autonoma de Chihuahua, Av. Politecnico Nacional 2714, Chihuahua, (Mexico); Lopez M, A. [Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027, 11801 Mexico D.F. (Mexico)

2003-07-01

Some calibration conditions of diffusion barrier charcoal canister (DBCC) detectors for measuring radon concentration in air were studied. A series of functional expressions and graphs were developed to describe relationship between radon concentration in air and the activity adsorbed in DBCC, when placed in small chambers. A semi-empirical expression for the DBCC calibration was obtained, based on the detector integration time and the adsorption coefficient of radon on activated charcoal. Both, the integration time for 10 % of DBCC of the same batch, and the adsorption coefficient of radon for the activated charcoal used in these detectors, were experimentally determined. Using these values as the calibration parameters, a semi-empirical calibration function was used for the interpretation of the radon activities in the detectors used for sampling more than 200 dwellings in the major cities of the state of Chihuahua, Mexico. (Author)

Single injection 51Cr EDTA plasma clearance determination in children using capillary blood samples

International Nuclear Information System (INIS)

Broechner-Mortensen, J.; Christoffersen, J.

1977-01-01

The reliability of a determination of the total 51 Cr EDTA plasma clearance (e) (and with it the glomerular filtration rate), by a simplified single injection method (injected dose: 4.5 μCi per kg b.w.) using capillary blood samples (0.2 ml), was investigated in twenty children. Clearance values determined from capillary blood samples did not differ significantly from those measured simultaneously from venous blood samples, the mean ratio+-SD being 1.02+-0.06(n = 10). The reproducibility (total day-to-day variation) of E determined from capillary blood samples was 6.7% in children with decreased renal function (n = 3) and 6.9% in children with normal renal function (n = 7). The present data indicate that the use of capillary blood samples is an accurate and very precise approach for determination of E in children. (Auth.)

Are Flow Injection-based Approaches Suitable for Automated Handling of Solid Samples?

DEFF Research Database (Denmark)

Miró, Manuel; Hansen, Elo Harald; Cerdà, Victor

Flow-based approaches were originally conceived for liquid-phase analysis, implying that constituents in solid samples generally had to be transferred into the liquid state, via appropriate batch pretreatment procedures, prior to analysis. Yet, in recent years, much effort has been focused...... electrolytic or aqueous leaching, on-line dialysis/microdialysis, in-line filtration, and pervaporation-based procedures have been successfully implemented in continuous flow/flow injection systems. In this communication, the new generation of flow analysis, including sequential injection, multicommutated flow.......g., soils, sediments, sludges), and thus, ascertaining the potential mobility, bioavailability and eventual impact of anthropogenic elements on biota [2]. In this context, the principles of sequential injection-microcolumn extraction (SI-MCE) for dynamic fractionation are explained in detail along...

Optimal sampling strategies to assess inulin clearance in children by the inulin single-injection method

NARCIS (Netherlands)

van Rossum, Lyonne K.; Mathot, Ron A. A.; Cransberg, Karlien; Vulto, Arnold G.

2003-01-01

Glomerular filtration rate in patients can be determined by estimating the plasma clearance of inulin with the single-injection method. In this method, a single bolus injection of inulin is administered and several blood samples are collected. For practical and convenient application of this method

Acupuncture Injection Combined with Electrokinetic Injection for Polydimethylsiloxane Microfluidic Devices

Directory of Open Access Journals (Sweden)

Ji Won Ha

2017-01-01

Full Text Available We recently reported acupuncture sample injection that leads to reproducible injection of nL-scale sample segments into a polydimethylsiloxane (PDMS microchannel for microchip capillary electrophoresis. The advantages of the acupuncture injection in microchip capillary electrophoresis include capability of minimizing sample loss and voltage control hardware and capability of introducing sample plugs into any desired position of a microchannel. However, the challenge in the previous study was to achieve reproducible, pL-scale sample injections into PDMS microchannels. In the present study, we introduce an acupuncture injection technique combined with electrokinetic injection (AICEI technique to inject pL-scale sample segments for microchip capillary electrophoresis. We carried out the capillary zone electrophoresis (CZE separation of FITC and fluorescein, and the mixture of 10 μM FITC and 10 μM fluorescein was separated completely by using the AICEI method.

Localization of gravitational wave sources with networks of advanced detectors

International Nuclear Information System (INIS)

Klimenko, S.; Mitselmakher, G.; Pankow, C.; Vedovato, G.; Drago, M.; Prodi, G.; Mazzolo, G.; Salemi, F.; Re, V.; Yakushin, I.

2011-01-01

Coincident observations with gravitational wave (GW) detectors and other astronomical instruments are among the main objectives of the experiments with the network of LIGO, Virgo, and GEO detectors. They will become a necessary part of the future GW astronomy as the next generation of advanced detectors comes online. The success of such joint observations directly depends on the source localization capabilities of the GW detectors. In this paper we present studies of the sky localization of transient GW sources with the future advanced detector networks and describe their fundamental properties. By reconstructing sky coordinates of ad hoc signals injected into simulated detector noise, we study the accuracy of the source localization and its dependence on the strength of injected signals, waveforms, and network configurations.

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

Hydrogen, carbon and oxygen determination in proxy material samples using a LaBr3:Ce detector

International Nuclear Information System (INIS)

Naqvi, A.A.; Al-Matouq, Faris A.; Khiari, F.Z.; Isab, A.A.; Raashid, M.; Khateeb-ur-Rehman

2013-01-01

Hydrogen, carbon and oxygen concentrations were measured in caffeine, urea, ammonium acetate and melamine bulk samples via 14 MeV neutron inelastic scattering using a LaBr 3 :Ce detector. The samples tested herein represent drugs, explosives and benign materials, respectively. Despite its intrinsic activity, the LaBr 3 :Ce detector performed well in detecting the hydrogen, carbon and oxygen elements. Because 5.1 MeV nitrogen gamma rays interfere with silicon and calcium prompt gamma rays from the room background, the nitrogen peak was not detected in the samples. An excellent agreement was observed between the experimental and theoretical yields of 2.22, 4.43 and 6.13 MeV gamma rays from the analyzed samples as a function of H, C and O concentrations, respectively. Within statistical errors, the minimum detectable concentration (MDC) of hydrogen, carbon and oxygen elements in the tested materials were consistent with previously reported MDC values for these elements measured in hydrocarbon samples. - Highlights: • Hydrogen, carbon and oxygen concentration measurement in bulk samples using 14 MeV neutrons induced prompt gamma rays. • Prompt gamma analysis of narcotics and explosive proxy materials e.g. ammonium acetate, caffeine, urea and melamine Bulk samples. • Prompt gamma detection using large cylindrical 76×76 mm 2 (diameter x height ) LaBr 3 :Ce detector. • Carbon/oxygen elemental ratio measurement from explosive and narcotics proxy material samples

Contributions for the application of a phoswich detector on the analysis of environmental samples

International Nuclear Information System (INIS)

Dalaqua Junior, L.

1989-01-01

The characteristics of a phoswich detector and the parameters of the pulse shape descrimination system are evaluated aiming the application on environmental analysis by direct low level gamma ray spectrometry. The calibration curves and adjustments for the pulse discrimination, detector resolution and homogeneity measurements are presented. Background reduction and the 210 Pb detection eficiency on evaporated sources are evaluated. The results obtained demonstrates the application potentiality on the analysis of environmental samples due to a high detection eficiency and good geometry conditions to the measurements. (author) [pt

CdTe detector based PIXE mapping of geological samples

Energy Technology Data Exchange (ETDEWEB)

Chaves, P.C., E-mail: cchaves@ctn.ist.utl.pt [Centro de Física Atómica da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); IST/ITN, Instituto Superior Técnico, Universidade Técnica de Lisboa, Campus Tecnológico e Nuclear, EN10, 2686-953 Sacavém (Portugal); Taborda, A. [Centro de Física Atómica da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); IST/ITN, Instituto Superior Técnico, Universidade Técnica de Lisboa, Campus Tecnológico e Nuclear, EN10, 2686-953 Sacavém (Portugal); Oliveira, D.P.S. de [Laboratório Nacional de Energia e Geologia (LNEG), Apartado 7586, 2611-901 Alfragide (Portugal); Reis, M.A. [Centro de Física Atómica da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); IST/ITN, Instituto Superior Técnico, Universidade Técnica de Lisboa, Campus Tecnológico e Nuclear, EN10, 2686-953 Sacavém (Portugal)

2014-01-01

A sample collected from a borehole drilled approximately 10 km ESE of Bragança, Trás-os-Montes, was analysed by standard and high energy PIXE at both CTN (previous ITN) PIXE setups. The sample is a fine-grained metapyroxenite grading to coarse-grained in the base with disseminated sulphides and fine veinlets of pyrrhotite and pyrite. Matrix composition was obtained at the standard PIXE setup using a 1.25 MeV H{sup +} beam at three different spots. Medium and high Z elemental concentrations were then determined using the DT2fit and DT2simul codes (Reis et al., 2008, 2013 [1,2]), on the spectra obtained in the High Resolution and High Energy (HRHE)-PIXE setup (Chaves et al., 2013 [3]) by irradiation of the sample with a 3.8 MeV proton beam provided by the CTN 3 MV Tandetron accelerator. In this paper we present results, discuss detection limits of the method and the added value of the use of the CdTe detector in this context.

Modified electrode voltammetric sensors for trace metals in environmental samples

Directory of Open Access Journals (Sweden)

Brett Christopher M.A.

2000-01-01

Full Text Available Nafion-modified mercury thin film electrodes have been investigated for the analysis of trace metals in environmental samples of waters and effluent by batch injection analysis with square wave anodic stripping voltammetry. The method, involving injection over the detector electrode of untreated samples of volume of the order of 50 microlitres has fast response, blocking and fouling of the electrode is minimum as shown by studies with surface-active components. Comparison is made between glassy carbon substrate electrodes and carbon fibre microelectrode array substrates, the latter leading to a small sensitivity enhancement. Application to analysis of river water and industrial effluent for labile zinc, cadmium, lead and copper ions is demonstrated in collected samples and after acid digestion.

A phoswich detector design for improved spatial sampling in PET

Science.gov (United States)

Thiessen, Jonathan D.; Koschan, Merry A.; Melcher, Charles L.; Meng, Fang; Schellenberg, Graham; Goertzen, Andrew L.

2018-02-01

Block detector designs, utilizing a pixelated scintillator array coupled to a photosensor array in a light-sharing design, are commonly used for positron emission tomography (PET) imaging applications. In practice, the spatial sampling of these designs is limited by the crystal pitch, which must be large enough for individual crystals to be resolved in the detector flood image. Replacing the conventional 2D scintillator array with an array of phoswich elements, each consisting of an optically coupled side-by-side scintillator pair, may improve spatial sampling in one direction of the array without requiring resolving smaller crystal elements. To test the feasibility of this design, a 4 × 4 phoswich array was constructed, with each phoswich element consisting of two optically coupled, 3 . 17 × 1 . 58 × 10mm3 LSO crystals co-doped with cerium and calcium. The amount of calcium doping was varied to create a 'fast' LSO crystal with decay time of 32.9 ns and a 'slow' LSO crystal with decay time of 41.2 ns. Using a Hamamatsu R8900U-00-C12 position-sensitive photomultiplier tube (PS-PMT) and a CAEN V1720 250 MS/s waveform digitizer, we were able to show effective discrimination of the fast and slow LSO crystals in the phoswich array. Although a side-by-side phoswich array is feasible, reflections at the crystal boundary due to a mismatch between the refractive index of the optical adhesive (n = 1 . 5) and LSO (n = 1 . 82) caused it to behave optically as an 8 × 4 array rather than a 4 × 4 array. Direct coupling of each phoswich element to individual photodetector elements may be necessary with the current phoswich array design. Alternatively, in order to implement this phoswich design with a conventional light sharing PET block detector, a high refractive index optical adhesive is necessary to closely match the refractive index of LSO.

Self-absorption corrections of various sample-detector geometries in gamma-ray spectrometry using sample Monte Carlo Simulations

International Nuclear Information System (INIS)

Ahmad Saat; Appleby, P.G.; Nolan, P.J.

1997-01-01

Corrections for self-absorption in gamma-ray spectrometry have been developed using a simple Monte Carlo simulation technique. The simulation enables the calculation of gamma-ray path lengths in the sample which, using available data, can be used to calculate self-absorption correction factors. The simulation was carried out on three sample geometries: disk, Marinelli beaker, and cylinder (for well-type detectors). Mathematical models and experimental measurements are used to evaluate the simulations. A good agreement of within a few percents was observed. The simulation results are also in good agreement with those reported in the literature. The simulation code was carried out in FORTRAN 90,

Hydrogen, carbon and oxygen determination in proxy material samples using a LaBr3:Ce detector.

Science.gov (United States)

Naqvi, A A; Al-Matouq, Faris A; Khiari, F Z; Isab, A A; Raashid, M; Khateeb-ur-Rehman

2013-08-01

Hydrogen, carbon and oxygen concentrations were measured in caffeine, urea, ammonium acetate and melamine bulk samples via 14 MeV neutron inelastic scattering using a LaBr3:Ce detector. The samples tested herein represent drugs, explosives and benign materials, respectively. Despite its intrinsic activity, the LaBr3:Ce detector performed well in detecting the hydrogen, carbon and oxygen elements. Because 5.1 MeV nitrogen gamma rays interfere with silicon and calcium prompt gamma rays from the room background, the nitrogen peak was not detected in the samples. An excellent agreement was observed between the experimental and theoretical yields of 2.22, 4.43 and 6.13 MeV gamma rays from the analyzed samples as a function of H, C and O concentrations, respectively. Within statistical errors, the minimum detectable concentration (MDC) of hydrogen, carbon and oxygen elements in the tested materials were consistent with previously reported MDC values for these elements measured in hydrocarbon samples. Copyright © 2013 Elsevier Ltd. All rights reserved.

Determination of the optional time for taking blood samples by single intravenous injection of 3H-leucine

International Nuclear Information System (INIS)

Meng Delian; Yao Junhu; Lu Jinyin; Wu Xiaobin; Liu Jun

2003-01-01

Twenty four young hens (1.5 kg of body weight, BW) were randomly divided into 4 groups. Every group was diet free (FAS) or force-fed a nitrogen-free diet (NFD) or the diet with 20% crude protein in which soybean meal or cotton seed meal was the sole nitrogen source (30 g DM/kg BW). 30 μCi 3 H-Leu/kg BW was intravenously injected into all birds just after force-fed or on fasting. Venous blood samples were taken at 5, 30 min, 4,24,36 and 48h after injection. The excreta during the whole period of 48h after injection was collected. Special radioactivities of nonprotein plasma at every time point and excreta were measured. The optional time of taking blood samples was 20-24 hours after injected 3 H-Leu

Water injection profiling

International Nuclear Information System (INIS)

Arnold, D.M.

1982-01-01

A method of neutron-gamma logging is described, in which water, injected in a cased well borehole with peforations, is irradiated with neutrons of 10 MeV or greater, and subsequent gamma radiation is detected by a pair of detectors along the borehole. Counting rates of detectors are analyzed in terms of two gamma ray energy windows. Linear flow velocity of fluid moving downward within the casing is used in conjunction with count rate data to determine volume flow rates of water moving in other directions. Apparatus includes a sonde with a neutron source and appropriate gamma sensors

Manual for the Epithermal Neutron Multiplicity Detector (ENMC) for Measurement of Impure MOX and Plutonium Samples

International Nuclear Information System (INIS)

Menlove, H. O.; Rael, C. D.; Kroncke, K. E.; DeAguero, K. J.

2004-01-01

We have designed a high-efficiency neutron detector for passive neutron coincidence and multiplicity counting of dirty scrap and bulk samples of plutonium. The counter will be used for the measurement of impure plutonium samples at the JNC MOX fabrication facility in Japan. The counter can also be used to create working standards from bulk process MOX. The detector uses advanced design "3He tubes to increase the efficiency and to shorten the neutron die-away time. The efficiency is 64% and the die-away time is 19.1 ?s. The Epithermal Neutron Multiplicity Counter (ENMC) is designed for high-precision measurements of bulk plutonium samples with diameters of less than 200 mm. The average neutron energy from the sample can be measured using the ratio of the inner ring of He-3 tubes to the outer ring. This report describes the hardware, performance, and calibration for the ENMC.

The charge collection in single side silicon microstrip detectors

CERN Document Server

Eremin, V V; Roe, S; Ruggiero, G; Weilhammer, Peter

2003-01-01

The transient current technique has been used to investigate signal formation in unirradiated silicon microstrip detectors, which are similar in geometry to those developed for the ATLAS experiment at LHC. Nanosecond pulsed infrared and red lasers were used to induce the signals under study. Two peculiarities in the detector performance were observed: an unexpectedly slow rise to the signal induced in a given strip when signals are injected opposite to the strip, and a long duration of the induced signal in comparison with the calculated drift time of charge carriers through the detector thickness - with a significant fraction of the charge being induced after charge carrier arrival. These major effects and details of the detector response for different positions of charge injection are discussed in the context of Ramo's theorem and compared with predictions arising from the more commonly studied phenomenon of signal formation in planar pad detectors.

A multi-channel photometric detector for multi-component analysis in flow injection analysis.

Science.gov (United States)

Tan, A; Huang, J; Geng, L; Xu, J; Zhao, X

1994-01-01

The detector, a multi-channel photometric detector, described in this paper was developed using multi-wavelength LEDs (light emitting diode) and phototransistors for absorbance measurement controlled by an Intel 8031 8-bit single chip microcomputer. Up to four flow cells can be attached to the detector. The LEDs and phototransistors are both inexpensive, and reliable. The results given by the detector for simultaneous determination of trace amounts of cobalt and cadmium in zinc sulphate electrolyte are reported. Because of the newly developed detector, this approach employs much less hardware apparatus than by employing conventional photometric detectors.

Flow injection spectrophotometric determination of low concentrations of orthosphate in natural waters employing ion exchange resin

International Nuclear Information System (INIS)

Pessenda, L.C.R.

1981-01-01

A simple and fast method for the determination of low concentrations of orthophosphate in natural waters is described. Ion exchange is incorporated into a flow injection system by usina a resin column in the sample loop of a proportion injector. Effects of sample aspiration rate, sampling time, eluting agent concentration, pumping rate of the sample carrier stream and interfaces, were investigated both using 32 PO 3- 4 or 31 PO 3- 4 with columns coupled to a gerger-muller detector and incorporated in a flow system with molybdenum blue colorinetry. (M.A.C.) [pt

Online sample concentration in partial-filling chiral electrokinetic chromatography – mass spectrometry.

Science.gov (United States)

Wuethrich, Alain; Haddad, Paul R; Quirino, Joselito P

2014-11-01

The concentration sensitivity of a racemic drug (chlorpheniramine maleate) in chiral capillary electrophoresis with electrospray ionization – mass spectrometric detection was improved ~500-fold via stacking. Enantiomeric separation was achieved through the use of a neutral chiral pseudostationary phase (2-hydroxpropyl-β-cyclodextrin), untreated fused-silica capillaries, and the application of a partial-filling technique to prevent the pseudostationary phase from entering the detector. A concentration factor of 50 resulted from field-enhanced sample injection(FESI). However, the higher concentration factor was achieved by combining FESI with micelle-to-solvent stacking (MSS) to increase sample load and focus the analyte band. MSS was achieved by injection of an ammonium lauryl sulfate micellar plug prior to sample injection. The sample diluent was a 20-fold dilution of the background electrolyte (50 mM ammonium acetate, pH 3.5) with 60% acetonitrile. This methodology provided a limit of detection (LOD) of as low as 5 ng/ml of the racemate.

Development of cryogenic tracking detectors for very high luminosity experiments

CERN Document Server

Härkönen, J; Anbinderis, T; Bates, R; de Boer, W; Borchi, E; Bruzzi, M; Buttar, C; Chen, W; Cindro, V; Czellar, S; Eremin, V; Furgeri, A; Gaubas, E; Heijne, E; Ilyashenko, I; Kalesinskas, V; Krause, M; Li, Z; Luukka, P; Mandic, I; Menichelli, D; Mikuz, M; Militaru, O; Mueller, S; Niinikoski, T O; O’Shea, V; Parkes, C; Piotrzkowski, K; Pirollo, S; Pusa, P; Räisänen, J; Rouby, X; Tuominen, E; Tuovinen, E; Vaitkus, J; Verbitskaya, E; Väyrynen, S; Zavrtanik, M

2009-01-01

Experimental results and simulations of Charge Collection Efficiency (CCE) of Current Injected Detectors (CIDs) are focused. CID is a concept where the current is limited by the space charge. The injected carriers will be trapped by the deep levels. This induces a stable electric field through the entire bulk regardless of the irradiation fluence the detector has been exposed. Our results show that the CCE of CIDs is about two times higher than of regular detectors when irradiated up to 1×1016 cm−2. The higher CCE is achieved already at −50 °C temperatures.

A comparison of continuous pneumatic nebulization and flow injection-direct injection nebulization for sample introduction in inductively coupled plasma-mass spectrometry

International Nuclear Information System (INIS)

Crain, J.S.; Kiely, J.T.

1995-08-01

Dilute nitric acid blanks and solutions containing Ni, Cd, Pb, and U (including two laboratory waste samples) were analyzed eighteen times over a two-month period using inductively coupled plasma-mass spectrometry (ICP-MS). Two different sample introduction techniques were employed: flow injection-direct injection nebulization (FI-DIN) and continuous pneumatic nebulization (CPN). Using comparable instrumental measurement procedures, FI-DIN analyses were 33% faster and generated 52% less waste than CPN analyses. Instrumental limits of detection obtained with FI-DIN and CPN were comparable but not equivalent (except in the case of Pb) because of nebulizer-related differences in sensitivity (i.e., signal per unit analyte concentration) and background. Substantial and statistically significant differences were found between FI-DIN and CPN Ni determinations, and in the case of the laboratory waste samples, there were also small but statistically significant differences between Cd determinations. These small (2 to 3%) differences were not related to polyatomic ion interference (e.g., 95 Mo 16 O + ), but in light of the time savings and waste reduction to be realized, they should not preclude the use of FI-DIN in place of CPN for determination of Cd, Pb, U and chemically

Use of a new ion-detector in the study of the jet plasma injected into a pulsed magnetic mirror configuration (deca I); Utilisation d'un nouveau detecteur d'ions dans l'etude du jet de plasma injecte dans deca I

Energy Technology Data Exchange (ETDEWEB)

Renaud, C [Association Euratom-CEA Cadarache, Groupe de Recherches sur la Fusion Controlee, 13 - Saint-Paul-lez-Durance (France). Centre d' Etudes Nucleaires

1963-07-01

The study of a high sensitivity ion detector coupled to an electrostatic analyser has permitted a large investigation of the plasma jet injected into a pulsed magnetic mirror configuration. In this detector the positive ions are accelerated through a potential of 30 kV; they strike a metallic target, on which they produce secondary electrons; these, in turn, are accelerated onto a plastic scintillator. The light pulses are detected with a photomultiplier. The gain of this device is about 10{sup 7}. If we make an admission of air into the vacuum system and again we make vacuum, the gain is not modified, since no special activated surfaces are situated in the detector. (author) [French] L'etude d'un detecteur d'ions de grande sensibilite, allie a un analyseur electrostatique a permis une investigation approfondie du jet de plasma injecte dans le dispositif d'Etude de Compression Adiabatique. Dans ce detecteur, les ions positifs sont acceleres par une difference de potentiel voisine de 30 kV, ils bombardent une cible metallique et creent des electrons secondaires qui sont a leur tour acceleres vers un scintillateur plastique. Les impulsions lumineuses sont alors detectees par un photomultiplicateur. Le gain obtenu pour l'ensemble du detecteur est voisin de 10{sup 7}. Le detecteur ne possedant pas de surfaces specialement activees, les remises a l'air n'entrainent pas de variation de gain. (auteur)

Water injection profiling by nuclear logging

International Nuclear Information System (INIS)

Arnold, D.M.

1980-01-01

This invention relates to nuclear logging techniques for determining the volume flow rates and flow directions of injected water moving behind a wellbore casing. The apparatus includes a sonde equipped with a neutron source and dual radiation detectors. Oxygen in the neutron irradiated water is transmitted to 16 N and the resultant primary and Compton scattered gamma rays are detected in two energy windows by both detectors. Count rate data is analysed in terms of the windows to obtain linear flow velocities for water flow within and behind the casing. Volume flow rates are determined for upward and downward flow, and horizontal volume flow into the surrounding formation is calculated. A complete injection profile may thus be obtained. (U.K.)

Automatic setting of the distance between sample and detector in gamma-ray spectroscopy

International Nuclear Information System (INIS)

Andeweg, A.H.

1980-01-01

An apparatus has been developed that automatically sets the distance from the sample to the detector according to the radioactivity of the sample. The distance-setting unit works in conjuction with an automatic sample changer, and is interconnected with other components so that the counting head automatically moves to the optimum distance for the analysis of a particular sample. The distance, which is indicated digitally in increments of 0,01 mm, can be set between 18 and 995 mm at count rates that can be preset between 1000 and 10 000 counts per second. On being tested, the instrument performed well within the desired range and accuracy. Under routine conditions, the spectra were much more accurate than before, especially when samples of different radioactivity were counted

Spatial resolution of 2D ionization chamber arrays for IMRT dose verification: single-detector size and sampling step width

International Nuclear Information System (INIS)

Poppe, Bjoern; Djouguela, Armand; Blechschmidt, Arne; Willborn, Kay; Ruehmann, Antje; Harder, Dietrich

2007-01-01

The spatial resolution of 2D detector arrays equipped with ionization chambers or diodes, used for the dose verification of IMRT treatment plans, is limited by the size of the single detector and the centre-to-centre distance between the detectors. Optimization criteria with regard to these parameters have been developed by combining concepts of dosimetry and pattern analysis. The 2D-ARRAY Type 10024 (PTW-Freiburg, Germany), single-chamber cross section 5 x 5 mm 2 , centre-to-centre distance between chambers in each row and column 10 mm, served as an example. Additional frames of given dose distributions can be taken by shifting the whole array parallel or perpendicular to the MLC leaves by, e.g., 5 mm. The size of the single detector is characterized by its lateral response function, a trapezoid with 5 mm top width and 9 mm base width. Therefore, values measured with the 2D array are regarded as sample values from the convolution product of the accelerator generated dose distribution and this lateral response function. Consequently, the dose verification, e.g., by means of the gamma index, is performed by comparing the measured values of the 2D array with the values of the convolution product of the treatment planning system (TPS) calculated dose distribution and the single-detector lateral response function. Sufficiently small misalignments of the measured dose distributions in comparison with the calculated ones can be detected since the lateral response function is symmetric with respect to the centre of the chamber, and the change of dose gradients due to the convolution is sufficiently small. The sampling step width of the 2D array should provide a set of sample values representative of the sampled distribution, which is achieved if the highest spatial frequency contained in this function does not exceed the 'Nyquist frequency', one half of the sampling frequency. Since the convolution products of IMRT-typical dose distributions and the single-detector

A feasibility study of a PET/MRI insert detector using strip-line and waveform sampling data acquisition.

Science.gov (United States)

Kim, H; Chen, C-T; Eclov, N; Ronzhin, A; Murat, P; Ramberg, E; Los, S; Wyrwicz, Alice M; Li, Limin; Kao, C-M

2015-06-01

We are developing a time-of-flight Positron Emission Tomography (PET) detector by using silicon photo-multipliers (SiPM) on a strip-line and high speed waveform sampling data acquisition. In this design, multiple SiPMs are connected on a single strip-line and signal waveforms on the strip-line are sampled at two ends of the strip to reduce readout channels while fully exploiting the fast time response of SiPMs. In addition to the deposited energy and time information, the position of the hit SiPM along the strip-line is determined by the arrival time difference of the waveform. Due to the insensitivity of the SiPMs to magnetic fields and the compact front-end electronics, the detector approach is highly attractive for developing a PET insert system for a magnetic resonance imaging (MRI) scanner to provide simultaneous PET/MR imaging. To investigate the feasibility, experimental tests using prototype detector modules have been conducted inside a 9.4 Tesla small animal MRI scanner (Bruker BioSpec 94/30 imaging spectrometer). On the prototype strip-line board, 16 SiPMs (5.2 mm pitch) are installed on two strip-lines and coupled to 2 × 8 LYSO scintillators (5.0 × 5.0 × 10.0 mm 3 with 5.2 mm pitch). The outputs of the strip-line boards are connected to a Domino-Ring-Sampler (DRS4) evaluation board for waveform sampling. Preliminary experimental results show that the effect of interference on the MRI image due to the PET detector is negligible and that PET detector performance is comparable with the results measured outside the MRI scanner.

Determination of sodium bis(2-ethylhexylsulfosuccinate (AOT surfactant with liquid chromatography: Comparative study of evaporative light scattering detector, ultraviolet detector and conductivity detector

Directory of Open Access Journals (Sweden)

Ho Ryul Ryu

2010-03-01

Full Text Available This work presents comparison of performance of ultraviolet (UV detector, conductivity detector (CD and evaporative light scattering detector (ELSD in terms of quantitative analysis of AOT (sodium bis(2-ethylhexylsulfosuccinate using liquid chromatography. The employed chromatographic condition, including an acetonitrile/water (45:55, v/v isocratic eluent system, is suitable for the three different detectors, and the figures of merits obtained by building up calibration plots are compared. The sensitivities of the detectors are in the order of ELSD ≈ CD >> UV detector. The linear range for quantification of AOT depends on the type of detector: the lower limits are in the order of UV detector (207 ㎍ mL-1 < CD (310 ㎍ mL-1 << ELSD (930 ㎍ mL-1, while the upper limits are 3720 ㎍ mL-1 for all the detectors (the maximum concentration of injected standard solution. The detection limits are 155 ㎍ mL-1 for ELSD, 78 ㎍ mL-1 for UV detector and 13 ㎍ mL-1 for CD, respectively. The figures of merit for each detector could be a guideline in choosing a detector in quantization of AOT. Furthermore, application of the chromatographic method to two commercial products is demonstrated.

Quantitative analysis of fragrance in selectable one dimensional or two dimensional gas chromatography-mass spectrometry with simultaneous detection of multiple detectors in single injection.

Science.gov (United States)

Tan, Hui Peng; Wan, Tow Shi; Min, Christina Liew Shu; Osborne, Murray; Ng, Khim Hui

2014-03-14

A selectable one-dimensional ((1)D) or two-dimensional ((2)D) gas chromatography-mass spectrometry (GC-MS) system coupled with flame ionization detector (FID) and olfactory detection port (ODP) was employed in this study to analyze perfume oil and fragrance in shower gel. A split/splitless (SSL) injector and a programmable temperature vaporization (PTV) injector are connected via a 2-way splitter of capillary flow technology (CFT) in this selectable (1)D/(2)D GC-MS/FID/ODP system to facilitate liquid sample injections and thermal desorption (TD) for stir bar sorptive extraction (SBSE) technique, respectively. The dual-linked injectors set-up enable the use of two different injector ports (one at a time) in single sequence run without having to relocate the (1)D capillary column from one inlet to another. Target analytes were separated in (1)D GC-MS/FID/ODP and followed by further separation of co-elution mixture from (1)D in (2)D GC-MS/FID/ODP in single injection without any instrumental reconfiguration. A (1)D/(2)D quantitative analysis method was developed and validated for its repeatability - tR; calculated linear retention indices (LRI); response ratio in both MS and FID signal, limit of detection (LOD), limit of quantitation (LOQ), as well as linearity over a concentration range. The method was successfully applied in quantitative analysis of perfume solution at different concentration level (RSD≤0.01%, n=5) and shower gel spiked with perfume at different dosages (RSD≤0.04%, n=5) with good recovery (96-103% for SSL injection; 94-107% for stir bar sorptive extraction-thermal desorption (SBSE-TD). Copyright © 2014 Elsevier B.V. All rights reserved.

Study of Efficiency Calibrations of HPGe Detectors for Radioactivity Measurements of Environmental Samples

International Nuclear Information System (INIS)

Harb, S.; Salahel Din, K.; Abbady, A.

2009-01-01

In this paper, we describe a method of calibrating of efficiency of a HPGe gamma-ray spectrometry of bulk environmental samples (Tea, crops, water, and soil) is a significant part of the environmental radioactivity measurements. Here we will discuss the full energy peak efficiency (FEPE) of three HPGe detectors it as a consequence, it is essential that the efficiency is determined for each set-up employed. Besides to take full advantage at gamma-ray spectrometry, a set of efficiency at several energies which covers the wide the range in energy, the large the number of radionuclides whose concentration can be determined to measure the main natural gamma-ray emitters, the efficiency should be known at least from 46.54 keV ( 210 Pb) to 1836 keV ( 88 Y). Radioactive sources were prepared from two different standards, a first mixed standard QC Y 40 containing 210 Pb, 241 Am, 109 Cd, and Co 57 , and the second QC Y 48 containing 241 Am, 109 Cd, 57 Co, 139 Ce, 113 Sn, 85 Sr, 137 Cs, 88 Y, and 60 Co is necessary in order to calculate the activity of the different radionuclides contained in a sample. In this work, we will study the efficiency calibration as a function of different parameters as:- Energy of gamma ray from 46.54 keV ( 210 Pb) to 1836 keV ( 88 Y), three different detectors A, B, and C, geometry of containers (point source, marinelli beaker, and cylindrical bottle 1 L), height of standard soil samples in bottle 250 ml, and density of standard environmental samples. These standard environmental sample must be measured before added standard solution because we will use the same environmental samples in order to consider the self absorption especially and composition in the case of volume samples.

Methods for Sampling and Measurement of Compressed Air Contaminants

Energy Technology Data Exchange (ETDEWEB)

Stroem, L

1976-10-15

In order to improve the technique for measuring oil and water entrained in a compressed air stream, a laboratory study has been made of some methods for sampling and measurement. For this purpose water or oil as artificial contaminants were injected in thin streams into a test loop, carrying dry compressed air. Sampling was performed in a vertical run, down-stream of the injection point. Wall attached liquid, coarse droplet flow, and fine droplet flow were sampled separately. The results were compared with two-phase flow theory and direct observation of liquid behaviour. In a study of sample transport through narrow tubes, it was observed that, below a certain liquid loading, the sample did not move, the liquid remaining stationary on the tubing wall. The basic analysis of the collected samples was made by gravimetric methods. Adsorption tubes were used with success to measure water vapour. A humidity meter with a sensor of the aluminium oxide type was found to be unreliable. Oil could be measured selectively by a flame ionization detector, the sample being pretreated in an evaporation- condensation unit

Methods for Sampling and Measurement of Compressed Air Contaminants

International Nuclear Information System (INIS)

Stroem, L.

1976-10-01

In order to improve the technique for measuring oil and water entrained in a compressed air stream, a laboratory study has been made of some methods for sampling and measurement. For this purpose water or oil as artificial contaminants were injected in thin streams into a test loop, carrying dry compressed air. Sampling was performed in a vertical run, down-stream of the injection point. Wall attached liquid, coarse droplet flow, and fine droplet flow were sampled separately. The results were compared with two-phase flow theory and direct observation of liquid behaviour. In a study of sample transport through narrow tubes, it was observed that, below a certain liquid loading, the sample did not move, the liquid remaining stationary on the tubing wall. The basic analysis of the collected samples was made by gravimetric methods. Adsorption tubes were used with success to measure water vapour. A humidity meter with a sensor of the aluminium oxide type was found to be unreliable. Oil could be measured selectively by a flame ionization detector, the sample being pretreated in an evaporation- condensation unit

Simultaneous determination of 2 aconitum alkaloids and 12 ginsenosides in Shenfu injection by ultraperformance liquid chromatography coupled with a photodiode array detector with few markers to determine multicomponents

Directory of Open Access Journals (Sweden)

Ai-Hua Ge

2015-06-01

Full Text Available A method with few markers to determine multicomponents was established and validated to evaluate the quality of Shenfu injection by ultraperformance liquid chromatography coupled with a photodiode array detector. The separations were performed on an ACQUITY UPLC BEH C18 (2.1 × 50 mm2, 1.7 μm column. Methanol and 0.1% formic acid aqueous solution were used as the mobile phase. The flow rate was 0.3 mL/min. 2 aconitum alkaloids and 12 ginsenosides could be perfectly separated within 15 minutes. Ginsenoside Rg1 and benzoylmesaconine, the easily available active components, were employed as the maker components to calculate the relative correction factors of other components in Shenfu injection, Panax ginseng and Aconitum carmichaeli. The external standard method was also established to validate the feasibility of the method with few markers to determine multicomponents. Parameter p and the principal component analysis method were employed to investigate the disparities among batches for the effective quality control of Shenfu injection. The results demonstrated that the ultraperformance liquid chromatography coupled with a photodiode array detector method with few markers to determine multicomponents could be used as a powerful tool for the quality evaluation of traditional Chinese medicines and their preparations.

Application of solid-phase micro extraction for the determination of pesticides in vegetable samples by gas chromatography with an electron capture detector

International Nuclear Information System (INIS)

Chai, Mee Kin; Tan, Guan Huat; Kumari, Asha

2008-01-01

A solid-phase micro extraction (SPME) method has been developed for the determination of 9 pesticides in 2 vegetables -cucumber and tomato - samples, based on direct immersion mode and subsequent desorption into the injection port of a gas chromatograph with an electron capture detector (GC-ECD). The main factors affecting the SPME process such as extraction time and temperature, desorption time and temperature, the effect of salt addition and fiber depth into the liner were studied and optimized. The analytical procedure proposed consisted of a 30 minute ultrasonic extraction of the target compounds from 1.0 g vegetable samples with 5 mL of distilled water. Then, the samples were filtered and topped up with distilled water to 10 mL. The analytes in this aqueous extract were extracted for 15 minutes with a 100 μm thickness polydimethylsiloxane SPME fiber. Relative standard deviations for triplicate analyses of samples were less than 10 %. The recoveries of the pesticides studied in cucumber and tomato ranged from 52 % to 82 % and the RSD were below 10 %. Therefore, the proposed method is applicable in the analysis of pesticides in vegetable matrices. SPME has been shown to be a simple extraction technique, which has a number of advantages such as solvent free extraction, simplicity and compatibility with the chromatographic analytical system. (author)

A pyrolysis/gas chromatographic method for the determination of hydrogen in solid samples

Science.gov (United States)

Carr, R. H.; Bustin, R.; Gibson, E. K.

1987-01-01

A method is described for the determination of hydrogen in solid samples. The sample is heated under vacuum after which the evolved gases are separated by gas chromatography with a helium ionization detector. The system is calibrated by injecting known amounts of hydrogen, as determined manometrically. The method, which is rapid and reliable, was checked for a variety of lunar soils; the limit of detection is about 10 ng of hydrogen.

Modification of ion chromatograph for analyses of radioactive samples

International Nuclear Information System (INIS)

Curfman, L.L.; Johnson, S.J.

1979-01-01

In ion chromatographic analysis, the sample is injected through a sample loop onto an analytical column where separation occurs. The sample then passes through a suppressor column to remove or neutralize background ions. A flow-through conductivity cell is used as a detector. Depending upon column and eluent selection, ion chromatography can be used for anion or cation analyses. Ion chromatography has proven to be a versatile analytical tool for the analysis of anions in Hanford waste samples. These radioactive samples range from caustic high salt solutions to hydrochloric acid dissolutions of insoluble sludges. Instrument modifications which provide safe and convenient handling of these samples without lengthening analysis time or altering instrument performance are described

Testing the sampling efficiency of a nuclear power station stack monitor

Energy Technology Data Exchange (ETDEWEB)

Stroem, L.H. [Instrumentinvest, Nykoeping (Sweden)

1997-08-01

The test method comprises the injection of known amounts of monodisperse particles in the stack air stream, at a suitable point upstream of the sampling installation. To find a suitable injection polls, the gas flow was mapped by means of a tracer gas, released in various points in the stack base. The resulting concentration distributions at the stack sampler level were observed by means of an array of gas detectors. An injection point that produced symmetrical distribution over the stack area, and low concentrations at the stack walls was selected for the particle tests. Monodisperse particles of 6, 10, and 19 {mu}m aerodynamic diameter, tagged with dysprosium, were dispersed in the selected injection point. Particle concentration at the sampler level was measured. The losses to the stack walls were found to be less than 10 %. The particle concentrations at the four sampler inlets were calculated from the observed gas distribution. The amount calculated to be aspirated into the sampler piping was compared with the quantity collected by the sampling train ordinary filter, to obtain the sampling line transmission efficiency. 1 ref., 2 figs.

Application of the Monte Carlo method for the efficiency calibration of CsI and NaI detectors for gamma-ray measurements from terrestrial samples

International Nuclear Information System (INIS)

Baccouche, S.; Al-Azmi, D.; Karunakara, N.; Trabelsi, A.

2012-01-01

Gamma-ray measurements in terrestrial/environmental samples require the use of high efficient detectors because of the low level of the radionuclide activity concentrations in the samples; thus scintillators are suitable for this purpose. Two scintillation detectors were studied in this work; CsI(Tl) and NaI(Tl) with identical size for measurement of terrestrial samples for performance study. This work describes a Monte Carlo method for making the full-energy efficiency calibration curves for both detectors using gamma-ray energies associated with the decay of naturally occurring radionuclides 137 Cs (661 keV), 40 K (1460 keV), 238 U ( 214 Bi, 1764 keV) and 232 Th ( 208 Tl, 2614 keV), which are found in terrestrial samples. The magnitude of the coincidence summing effect occurring for the 2614 keV emission of 208 Tl is assessed by simulation. The method provides an efficient tool to make the full-energy efficiency calibration curve for scintillation detectors for any samples geometry and volume in order to determine accurate activity concentrations in terrestrial samples. - Highlights: ► CsI (Tl) and NaI (Tl) detectors were studied for the measurement of terrestrial samples. ► Monte Carlo method was used for efficiency calibration using natural gamma emitting terrestrial radionuclides. ► The coincidence summing effect occurring for the 2614 keV emission of 208 Tl is assessed by simulation.

Effect of detector collimator and sample thickness on 0.662 MeV multiply Compton-scattered gamma rays

International Nuclear Information System (INIS)

Singh, Manpreet; Singh, Gurvinderjit; Sandhu, B.S.; Singh, Bhajan

2006-01-01

The simultaneous effect of detector collimator and sample thickness on 0.662 MeV multiply Compton-scattered gamma photons was studied experimentally. An intense collimated beam, obtained from 6-Ci 137 Cs source, is allowed to impinge on cylindrical aluminium samples of varying diameter and the scattered photons are detected by a 51 mmx51 mm NaI(Tl) scintillation detector placed at 90 o to the incident beam. The full energy peak corresponding to singly scattered events is reconstructed analytically. The thickness at which the multiply scattered events saturate is determined for different detector collimators. The parameters like signal-to-noise ratio and multiply scatter fraction (MSF) have also been deduced and support the work carried out by Shengli et al. [2000. EGS4 simulation of Compton scattering for nondestructive testing. KEK proceedings 200-20, Tsukuba, Japan, pp. 216-223] and Barnea et al. [1995. A study of multiple scattering background in Compton scatter imaging. NDT and E International 28, 155-162] based upon Monte Carlo calculations

Comparing Respondent-Driven Sampling and Targeted Sampling Methods of Recruiting Injection Drug Users in San Francisco

Science.gov (United States)

Malekinejad, Mohsen; Vaudrey, Jason; Martinez, Alexis N.; Lorvick, Jennifer; McFarland, Willi; Raymond, H. Fisher

2010-01-01

The objective of this article is to compare demographic characteristics, risk behaviors, and service utilization among injection drug users (IDUs) recruited from two separate studies in San Francisco in 2005, one which used targeted sampling (TS) and the other which used respondent-driven sampling (RDS). IDUs were recruited using TS (n = 651) and RDS (n = 534) and participated in quantitative interviews that included demographic characteristics, risk behaviors, and service utilization. Prevalence estimates and 95% confidence intervals (CIs) were calculated to assess whether there were differences in these variables by sampling method. There was overlap in 95% CIs for all demographic variables except African American race (TS: 45%, 53%; RDS: 29%, 44%). Maps showed that the proportion of IDUs distributed across zip codes were similar for the TS and RDS sample, with the exception of a single zip code that was more represented in the TS sample. This zip code includes an isolated, predominantly African American neighborhood where only the TS study had a field site. Risk behavior estimates were similar for both TS and RDS samples, although self-reported hepatitis C infection was lower in the RDS sample. In terms of service utilization, more IDUs in the RDS sample reported no recent use of drug treatment and syringe exchange program services. Our study suggests that perhaps a hybrid sampling plan is best suited for recruiting IDUs in San Francisco, whereby the more intensive ethnographic and secondary analysis components of TS would aid in the planning of seed placement and field locations for RDS. PMID:20582573

Study on the etching conditions of polycarbonate detectors for particle analysis of safeguards environmental samples

International Nuclear Information System (INIS)

Iguchi, K.; Esaka, K.T.; Lee, C.G.; Inagawa, J.; Esaka, F.; Onodera, T.; Fukuyama, H.; Suzuki, D.; Sakurai, S.; Watanabe, K.; Usuda, S.

2005-01-01

The fission track technique was applied to the particle analysis for safeguards environmental samples to obtain information about the isotope ratio of nuclear materials in individual particles. To detect the particles containing nuclear material with high detection efficiency and less particle loss, the influence of uranium enrichments on etching conditions of a fission track detector made of polycarbonate was investigated. It was shown that the increase in uranium enrichment shortened the suitable etching time both for particle detection and for less particle loss. From the results obtained, it was suggested that the screening of the uranium particles according to the enrichment is possible by controlling the etching time of the detector

Detector performance of the ALICE silicon pixel detector

CERN Document Server

Cavicchioli, C

2011-01-01

The ALICE Silicon Pixel Detector (SPD) forms the two innermost layers of the ALICE Inner Tracking System (ITS). It consists of two barrel layers of hybrid silicon pixel detectors at radii of 39 and 76 mm. The physics targets of the ALICE experiment require that the material budget of the SPD is kept within approximate to 1\\%X(0) per layer. This has set some stringent constraints on the design and construction of the SPD. A unique feature of the ALICE SPD is that it is capable of providing a prompt trigger signal, called Fast-OR, which contributes to the L0 trigger decision. The pixel trigger system allows to apply a set of algorithms for the trigger selection, and its output is sent to the Central Trigger Processor (CTP). The detector has been installed in the experiment in summer 2007. During the first injection tests in June 2008 the SPD was able to record the very first sign of life of the LHC by registering secondary particles from the beam dumped upstream the ALICE experiment. In the following months the...

Flow injection gas chromatography with sulfur chemiluminescence detection for the analysis of total sulfur in complex hydrocarbon matrixes.

Science.gov (United States)

Hua, Yujuan; Hawryluk, Myron; Gras, Ronda; Shearer, Randall; Luong, Jim

2018-01-01

A fast and reliable analytical technique for the determination of total sulfur levels in complex hydrocarbon matrices is introduced. The method employed flow injection technique using a gas chromatograph as a sample introduction device and a gas phase dual-plasma sulfur chemiluminescence detector for sulfur quantification. Using the technique described, total sulfur measurement in challenging hydrocarbon matrices can be achieved in less than 10 s with sample-to-sample time ideal for fast analysis or trace sulfur analysis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A new method for determining the uranium and thorium distribution in volcanic rock samples using solid state nuclear track detectors

International Nuclear Information System (INIS)

Misdaq, M.A.; Bakhchi, A.; Ktata, A.; Koutit, A.; Lamine, J.; Ait nouh, F.; Oufni, L.

2000-01-01

A method based on using solid state nuclear track detectors (SSNTD) CR- 39 and LR-115 type II and calculating the probabilities for the alpha particles emitted by the uranium and thorium series to reach and be registered on these films was utilized for uranium and thorium contents determination in various geological samples. The distribution of uranium and thorium in different volcanic rocks has been investigated using the track fission method. In this work, the uranium and thorium contents have been determined in different volcanic rock samples by using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTD). The mean critical angles of etching of the solid state nuclear track detectors utilized have been calculated. A petrographical study of the volcanic rock thin layers studied has been conducted. The uranium and thorium distribution inside different rock thin layers has been studied. The mechanism of inclusion of the uranium and thorium nuclei inside the volcanic rock samples studied has been investigated. (author)

Determination of drugs in biological fluids by direct injection of samples for liquid-chromatographic analysis.

Science.gov (United States)

Mullett, Wayne M

2007-03-10

The analysis of drugs in various biological fluids is an important criterion for the determination of the physiological performance of a drug. After sampling of the biological fluid, the next step in the analytical process is sample preparation. The complexity of biological fluids adds to the challenge of direct determination of the drug by chromatographic analysis, therefore demanding a sample preparation step that is often time-consuming, tedious, and frequently overlooked. However, direct on-line injection methods offer the advantage of reducing sample preparation steps and enabling effective pre-concentration and clean-up of biological fluids. These procedures can be automated and therefore reduce the requirements for handling potentially infectious biomaterial, improve reproducibility, and minimize sample manipulations and potential contamination. The objective of this review is to present an overview of the existing literature with emphasis on advances in automated sample preparation methods for liquid-chromatographic methods. More specifically, this review concentrates on the use of direct injection techniques, such as restricted-access materials, turbulent-flow chromatography and other automated on-line solid-phase extraction (SPE) procedures. It also includes short overviews of emerging automated extraction-phase technologies, such as molecularly imprinted polymers, in-tube solid-phase micro-extraction, and micro-extraction in a packed syringe for a more selective extraction of analytes from complex samples, providing further improvements in the analysis of biological materials. Lastly, the outlook for these methods and potential new applications for these technologies are briefly discussed.

Detectors, sampling, shielding, and electronics for positron emission tomography

International Nuclear Information System (INIS)

Derenzo, S.E.

1981-08-01

A brief discussion of the important design elements for positron emission tomographs is presented. The conclusions are that the instrumentation can be improved by the use of larger numbers of small, efficient detectors closely packed in many rings, the development of new detector materials, and novel electronic designs to reduce the deadtime and increase maximum event rates

Large-volume injection of sample diluents not miscible with the mobile phase as an alternative approach in sample preparation for bioanalysis: an application for fenspiride bioequivalence.

Science.gov (United States)

Medvedovici, Andrei; Udrescu, Stefan; Albu, Florin; Tache, Florentin; David, Victor

2011-09-01

Liquid-liquid extraction of target compounds from biological matrices followed by the injection of a large volume from the organic layer into the chromatographic column operated under reversed-phase (RP) conditions would successfully combine the selectivity and the straightforward character of the procedure in order to enhance sensitivity, compared with the usual approach of involving solvent evaporation and residue re-dissolution. Large-volume injection of samples in diluents that are not miscible with the mobile phase was recently introduced in chromatographic practice. The risk of random errors produced during the manipulation of samples is also substantially reduced. A bioanalytical method designed for the bioequivalence of fenspiride containing pharmaceutical formulations was based on a sample preparation procedure involving extraction of the target analyte and the internal standard (trimetazidine) from alkalinized plasma samples in 1-octanol. A volume of 75 µl from the octanol layer was directly injected on a Zorbax SB C18 Rapid Resolution, 50 mm length × 4.6 mm internal diameter × 1.8 µm particle size column, with the RP separation being carried out under gradient elution conditions. Detection was made through positive ESI and MS/MS. Aspects related to method development and validation are discussed. The bioanalytical method was successfully applied to assess bioequivalence of a modified release pharmaceutical formulation containing 80 mg fenspiride hydrochloride during two different studies carried out as single-dose administration under fasting and fed conditions (four arms), and multiple doses administration, respectively. The quality attributes assigned to the bioanalytical method, as resulting from its application to the bioequivalence studies, are highlighted and fully demonstrate that sample preparation based on large-volume injection of immiscible diluents has an increased potential for application in bioanalysis.

Application of the Monte Carlo method for the efficiency calibration of CsI and NaI detectors for gamma-ray measurements from terrestrial samples

Energy Technology Data Exchange (ETDEWEB)

Baccouche, S., E-mail: souad.baccouche@cnstn.rnrt.tn [UR-MDTN, National Center for Nuclear Sciences and Technology, Technopole Sidi Thabet, 2020 Sidi Thabet (Tunisia); Al-Azmi, D., E-mail: ds.alazmi@paaet.edu.kw [Department of Applied Sciences, College of Technological Studies, Public Authority for Applied Education and Training, Shuwaikh, P.O. Box 42325, Code 70654 (Kuwait); Karunakara, N., E-mail: karunakara_n@yahoo.com [University Science Instrumentation Centre, Mangalore University, Mangalagangotri 574199 (India); Trabelsi, A., E-mail: adel.trabelsi@fst.rnu.tn [UR-MDTN, National Center for Nuclear Sciences and Technology, Technopole Sidi Thabet, 2020 Sidi Thabet (Tunisia); UR-UPNHE, Faculty of Sciences of Tunis, El-Manar University, 2092 Tunis (Tunisia)

2012-01-15

Gamma-ray measurements in terrestrial/environmental samples require the use of high efficient detectors because of the low level of the radionuclide activity concentrations in the samples; thus scintillators are suitable for this purpose. Two scintillation detectors were studied in this work; CsI(Tl) and NaI(Tl) with identical size for measurement of terrestrial samples for performance study. This work describes a Monte Carlo method for making the full-energy efficiency calibration curves for both detectors using gamma-ray energies associated with the decay of naturally occurring radionuclides {sup 137}Cs (661 keV), {sup 40}K (1460 keV), {sup 238}U ({sup 214}Bi, 1764 keV) and {sup 232}Th ({sup 208}Tl, 2614 keV), which are found in terrestrial samples. The magnitude of the coincidence summing effect occurring for the 2614 keV emission of {sup 208}Tl is assessed by simulation. The method provides an efficient tool to make the full-energy efficiency calibration curve for scintillation detectors for any samples geometry and volume in order to determine accurate activity concentrations in terrestrial samples. - Highlights: Black-Right-Pointing-Pointer CsI (Tl) and NaI (Tl) detectors were studied for the measurement of terrestrial samples. Black-Right-Pointing-Pointer Monte Carlo method was used for efficiency calibration using natural gamma emitting terrestrial radionuclides. Black-Right-Pointing-Pointer The coincidence summing effect occurring for the 2614 keV emission of {sup 208}Tl is assessed by simulation.

Digital Microfluidics Sample Analyzer

Science.gov (United States)

Pollack, Michael G.; Srinivasan, Vijay; Eckhardt, Allen; Paik, Philip Y.; Sudarsan, Arjun; Shenderov, Alex; Hua, Zhishan; Pamula, Vamsee K.

2010-01-01

Three innovations address the needs of the medical world with regard to microfluidic manipulation and testing of physiological samples in ways that can benefit point-of-care needs for patients such as premature infants, for which drawing of blood for continuous tests can be life-threatening in their own right, and for expedited results. A chip with sample injection elements, reservoirs (and waste), droplet formation structures, fluidic pathways, mixing areas, and optical detection sites, was fabricated to test the various components of the microfluidic platform, both individually and in integrated fashion. The droplet control system permits a user to control droplet microactuator system functions, such as droplet operations and detector operations. Also, the programming system allows a user to develop software routines for controlling droplet microactuator system functions, such as droplet operations and detector operations. A chip is incorporated into the system with a controller, a detector, input and output devices, and software. A novel filler fluid formulation is used for the transport of droplets with high protein concentrations. Novel assemblies for detection of photons from an on-chip droplet are present, as well as novel systems for conducting various assays, such as immunoassays and PCR (polymerase chain reaction). The lab-on-a-chip (a.k.a., lab-on-a-printed-circuit board) processes physiological samples and comprises a system for automated, multi-analyte measurements using sub-microliter samples of human serum. The invention also relates to a diagnostic chip and system including the chip that performs many of the routine operations of a central labbased chemistry analyzer, integrating, for example, colorimetric assays (e.g., for proteins), chemiluminescence/fluorescence assays (e.g., for enzymes, electrolytes, and gases), and/or conductometric assays (e.g., for hematocrit on plasma and whole blood) on a single chip platform.

Analysis of urinary neurotransmitters by capillary electrophoresis: Sensitivity enhancement using field-amplified sample injection and molecular imprinted polymer solid phase extraction

International Nuclear Information System (INIS)

Claude, Berengere; Nehme, Reine; Morin, Philippe

2011-01-01

Highlights: → Field-amplified sample injection (FASI) improves the sensitivity of capillary electrophoresis through the online pre-concentration samples. → The cationic analytes are stacked at the capillary inlet between a zone of low conductivity - sample and pre-injection plug - and a zone of high conductivity - running buffer. → The limits of quantification are 500 times lower than those obtained with hydrodynamic injection. → The presence of salts in the matrix greatly reduces the sensitivity of the FASI/CE-UV method. - Abstract: Capillary electrophoresis (CE) has been investigated for the analysis of some neurotransmitters, dopamine (DA), 3-methoxytyramine (3-MT) and serotonin (5-hydroxytryptamine, 5-HT) at nanomolar concentrations in urine. Field-amplified sample injection (FASI) has been used to improve the sensitivity through the online pre-concentration samples. The cationic analytes were stacked at the capillary inlet between a zone of low conductivity - sample and pre-injection plug - and a zone of high conductivity - running buffer. Several FASI parameters have been optimized (ionic strength of the running buffer, concentration of the sample protonation agent, composition of the sample solvent and nature of the pre-injection plug). Best results were obtained using H 3 PO 4 -LiOH (pH 4, ionic strength of 80 mmol L -1 ) as running buffer, 100 μmol L -1 of H 3 PO 4 in methanol-water 90/10 (v/v) as sample solvent and 100 μmol L -1 of H 3 PO 4 in water for the pre-injection plug. In these conditions, the linearity was verified in the 50-300 nmol L -1 concentration range for DA, 3-MT and 5-HT with a determination coefficient (r 2 ) higher than 0.99. The limits of quantification (10 nmol L -1 for DA and 3-MT, 5.9 nmol L -1 for 5-HT) were 500 times lower than those obtained with hydrodynamic injection. However, if this method is applied to the analysis of neurotransmitters in urine, the presence of salts in the matrix greatly reduces the sensitivity

Analysis of urinary neurotransmitters by capillary electrophoresis: Sensitivity enhancement using field-amplified sample injection and molecular imprinted polymer solid phase extraction

Energy Technology Data Exchange (ETDEWEB)

Claude, Berengere, E-mail: berengere.claude@univ-orleans.fr [Institut de Chimie Organique et Analytique, CNRS FR 2708 UMR 6005, Universite d' Orleans, 45067 Orleans (France); Nehme, Reine; Morin, Philippe [Institut de Chimie Organique et Analytique, CNRS FR 2708 UMR 6005, Universite d' Orleans, 45067 Orleans (France)

2011-08-12

Highlights: {yields} Field-amplified sample injection (FASI) improves the sensitivity of capillary electrophoresis through the online pre-concentration samples. {yields} The cationic analytes are stacked at the capillary inlet between a zone of low conductivity - sample and pre-injection plug - and a zone of high conductivity - running buffer. {yields} The limits of quantification are 500 times lower than those obtained with hydrodynamic injection. {yields} The presence of salts in the matrix greatly reduces the sensitivity of the FASI/CE-UV method. - Abstract: Capillary electrophoresis (CE) has been investigated for the analysis of some neurotransmitters, dopamine (DA), 3-methoxytyramine (3-MT) and serotonin (5-hydroxytryptamine, 5-HT) at nanomolar concentrations in urine. Field-amplified sample injection (FASI) has been used to improve the sensitivity through the online pre-concentration samples. The cationic analytes were stacked at the capillary inlet between a zone of low conductivity - sample and pre-injection plug - and a zone of high conductivity - running buffer. Several FASI parameters have been optimized (ionic strength of the running buffer, concentration of the sample protonation agent, composition of the sample solvent and nature of the pre-injection plug). Best results were obtained using H{sub 3}PO{sub 4}-LiOH (pH 4, ionic strength of 80 mmol L{sup -1}) as running buffer, 100 {mu}mol L{sup -1} of H{sub 3}PO{sub 4} in methanol-water 90/10 (v/v) as sample solvent and 100 {mu}mol L{sup -1} of H{sub 3}PO{sub 4} in water for the pre-injection plug. In these conditions, the linearity was verified in the 50-300 nmol L{sup -1} concentration range for DA, 3-MT and 5-HT with a determination coefficient (r{sup 2}) higher than 0.99. The limits of quantification (10 nmol L{sup -1} for DA and 3-MT, 5.9 nmol L{sup -1} for 5-HT) were 500 times lower than those obtained with hydrodynamic injection. However, if this method is applied to the analysis of

Rapid determination of 99Tc in environmental samples by high resolution ICP-MS coupled with on-line flow injection system

International Nuclear Information System (INIS)

Kim, C.K.; Kim, C.S.; Rho, B.H.; Lee, J.I.

2002-01-01

High resolution inductively coupled plasma mass spectrometry coupled with an on-line flow injection system (FI-HR-ICP-MS) was applied to determine the ultra-trace level 99 Tc in soil. The flow injection system (PrepLab TM ) was composed of two TEVA-Spec R resins, reduced remarkably the sample amounts and the analysis time, compared to the conventional analytical methods. In the flow injection system, Mo and Ru were sufficiently eliminated by using the flow injection system, with the decontamination factors of 1.6 x 10 4 and 9.9 x 10 5 , respectively. With the present method, it was possible to determine ultra-low level of 99 Tc in 3∼6 soil at 3-5 hours of analysis time per sample. The relative standard deviation for each sample was less than 4%. The detection limits for 99 Tc was 85 fg x ml -1 (0.05 mBq x ml -1 ), which was calculated from the three times standard deviation of the count rate of the blank. (author)

Accurate determination of sulfur in gasoline and related fuel samples using isotope dilution ICP-MS with direct sample injection and microwave-assisted digestion.

Science.gov (United States)

Heilmann, Jens; Boulyga, Sergei F; Heumann, Klaus G

2004-09-01

Inductively coupled plasma isotope-dilution mass spectrometry (ICP-IDMS) with direct injection of isotope-diluted samples into the plasma, using a direct injection high-efficiency nebulizer (DIHEN), was applied for accurate sulfur determinations in sulfur-free premium gasoline, gas oil, diesel fuel, and heating oil. For direct injection a micro-emulsion consisting of the corresponding organic sample and an aqueous 34S-enriched spike solution with additions of tetrahydronaphthalene and Triton X-100, was prepared. The ICP-MS parameters were optimized with respect to high sulfur ion intensities, low mass-bias values, and high precision of 32S/34S ratio measurements. For validation of the DIHEN-ICP-IDMS method two certified gas oil reference materials (BCR 107 and BCR 672) were analyzed. For comparison a wet-chemical ICP-IDMS method was applied with microwave-assisted digestion using decomposition of samples in a closed quartz vessel inserted into a normal microwave system. The results from both ICP-IDMS methods agree well with the certified values of the reference materials and also with each other for analyses of other samples. However, the standard deviation of DIHEN-ICP-IDMS was about a factor of two higher (5-6% RSD at concentration levels above 100 mircog g(-1)) compared with those of wet-chemical ICP-IDMS, mainly due to inhomogeneities of the micro-emulsion, which causes additional plasma instabilities. Detection limits of 4 and 18 microg g(-1) were obtained for ICP-IDMS in connection with microwave-assisted digestion and DIHEN-ICP-IDMS, respectively, with a sulfur background of the used Milli-Q water as the main limiting factor for both methods.

Accurate determination of sulfur in gasoline and related fuel samples using isotope dilution ICP-MS with direct sample injection and microwave-assisted digestion

Energy Technology Data Exchange (ETDEWEB)

Heilmann, Jens; Boulyga, Sergei F.; Heumann, Klaus G. [Johannes Gutenberg-University, Institute of Inorganic Chemistry and Analytical Chemistry, Mainz (Germany)

2004-09-01

Inductively coupled plasma isotope-dilution mass spectrometry (ICP-IDMS) with direct injection of isotope-diluted samples into the plasma, using a direct injection high-efficiency nebulizer (DIHEN), was applied for accurate sulfur determinations in sulfur-free premium gasoline, gas oil, diesel fuel, and heating oil. For direct injection a micro-emulsion consisting of the corresponding organic sample and an aqueous {sup 34}S-enriched spike solution with additions of tetrahydronaphthalene and Triton X-100, was prepared. The ICP-MS parameters were optimized with respect to high sulfur ion intensities, low mass-bias values, and high precision of {sup 32}S/{sup 34}S ratio measurements. For validation of the DIHEN-ICP-IDMS method two certified gas oil reference materials (BCR 107 and BCR 672) were analyzed. For comparison a wet-chemical ICP-IDMS method was applied with microwave-assisted digestion using decomposition of samples in a closed quartz vessel inserted into a normal microwave system. The results from both ICP-IDMS methods agree well with the certified values of the reference materials and also with each other for analyses of other samples. However, the standard deviation of DIHEN-ICP-IDMS was about a factor of two higher (5-6% RSD at concentration levels above 100 {mu}g g{sup -1}) compared with those of wet-chemical ICP-IDMS, mainly due to inhomogeneities of the micro-emulsion, which causes additional plasma instabilities. Detection limits of 4 and 18 {mu}g g{sup -1} were obtained for ICP-IDMS in connection with microwave-assisted digestion and DIHEN-ICP-IDMS, respectively, with a sulfur background of the used Milli-Q water as the main limiting factor for both methods. (orig.)

Development of cryogenic Si detectors by CERN RD39 Collaboration for ultra radiation hardness in SLHC environment

CERN Document Server

Li, Z; Anbinderis, P; Anbinderis, T; D’Ambrosio, N; de Boer, Wim; Borchi, E; Borer, K; Bruzzi, M; Buontempo, S; Chen, W; Cindro, V; Dierlamm, A; Eremin, V; Gaubas, E; Gorbatenko, V; Grigoriev, E; Hauler, F; Heijne, Erik H M; Heising, S; Hempel, O; Herzog, R; Härkönen, J; Ilyashenko, I; Janos, S; Jungermann, L; Kalesinskas, V; Kapturauskas, J; Laiho, R; Luukka, P; Mandic, I; De Masi, R; Menichelli, D; Mikuz, M; Militaru, O; Niinikosky, T O; O’Shea, V; Pagano, S; Paul, S; Piotrzkowski, K; Pretzl, K; Rato-Mendes, P; Rouby, X; Ruggiero, G; Smith, K; Sonderegger, P; Sousa, P; Tuominen, E; Tuovinen, E; Verbitskaya, E; Vaitkus, J; Wobst, E; Zavrtanik, M

2007-01-01

There are two key approaches in our CERN RD 39 Collaboration efforts to obtain ultra-radiation-hard Si detectors: (1) use of the charge/current injection to manipulate the detector internal electric field in such a way that it can be depleted at a modest bias voltage at cryogenic temperature range (150 K), and (2) freezing out of the trapping centers that affects the CCE at cryogenic temperatures lower than that of the liquid nitrogen (LN2) temperature. In our first approach, we have developed the advanced radiation hard detectors using charge or current injection, the current injected diodes (CID). In a CID, the electric field is controlled by injected current, which is limited by the space charge, yielding a nearly uniform electric field in the detector, independent of the radiation fluence. In our second approach, we have developed models of radiation-induced trapping levels and the physics of their freezing out at cryogenic temperatures.

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

Characterising large area silicon drift detectors with MOS injectors

International Nuclear Information System (INIS)

Bonvicini, V.; Rashevsky, A.; Vacchi, A.

1999-01-01

In the framework of the INFN DSI project, the first prototypes of a large-area Silicon Drift Detector (SDD) have been designed and produced on 5'' diameter wafers of Neutron Transmutation Doped (NTD) silicon with a resistivity of 3000 Ω·cm. The detector is a 'butterfly' bi-directional structure with a drift length of 32 mm and the drifting charge is collected by two arrays of anodes having a pitch of 200 μm. The high-voltage divider is integrated on-board and is realised with p + implantations. For test and calibration purposes, the detector has a new type of MOS injector. The paper presents results obtained to injecting charge at the maximum drift distance (32mm) from the anodes by means of the MOS injecting structure, As front-end electronics, the authors have used a 32-channels low-noise bipolar VLSI circuit (OLA, Omni-purpose Low-noise Amplifer) specifically designed for silicon drift detectors. The uniformity of the drift time in different regions of the sensitive area and its dependence on the ambient temperature are studied

Reverse phase high performance liquid chromatographic method development based on ultravioletvisible detector for the analysis of 1-hydroxypyrene (PAH biomarker) in human urine.

Science.gov (United States)

Kamal, Atif; Gulfraz, Mohammad; Anwar, Mohammad Asad; Malik, Riffat Naseem

2015-01-01

1-hydroxypyrene is an important biomarker of exposure to polycyclic aromatic hydrocarbons (PAHs), which appears in the urine of exposed human subjects. In developing countries, where advanced instruments are not available, the importance of this biomarker demands convenient and sensitive methods for determination purposes. This study aimed at developing a methodology to quantify 1-hydroxypyrene (a biomarker of PAHs exposure) based on the UV-visible detector in the reverse phase high pressure liquid chromatography (HPLC). A 20 μl injection of sample was used for manual injection into the HPLC Shimadzu, equipped with the SPD-20 A UV-visible detector, the LC-20AT pump and the DGU-20A5 degasser. The C-18 column was used for the purpose of the analysis. The method showed a good linearity (the range: R2 = 0.979-0.989), and high detectability up to the nmol level. The average retention was 6.37, with the accuracy of 2%, and the percentage of recovery remained 108%. The overall performance of this method was comparable (in terms of detection sensitivity) and relatively better than previously reported studies using the HPLC system equipped with the UV-detector. This method is suitable and reliable for the detection/quantification of the 1-OHP in human urine samples, using the UV-detector, however, it is less sensitive as compared to the results of a florescence detector. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Spectrophotometric flow-injection analysis assay of tetracycline antibiotics using a dual light-emitting diode based detector

Directory of Open Access Journals (Sweden)

Prinya Masawat

2008-02-01

Full Text Available In this paper, a small dual light-emitting diode (LED-based detector for FIA process analyser has been designed. The detector’s optical parts comprise a flow-through cell, a dual-blue LED and a photodiode. Neither mirrors nor lenses are used. The optical path for the first LED detects the blank, while the other LED detects the sample. The detector’s electronic components including a signal amplifier and an A/D converter are integrated on one small board connected to a PC for measuring the results. The designed spectrophotometric detector was used for the determination of tetracycline antibiotics. Uranyl acetate was used as a reagent forming orange-red complexes with the drugs in N,N– dimethylformamide. The complexes show absorption maxima at 410, 416 and 408 nm for tetracycline hydrochloride (TCH, chlortetracycline hydrochloride (CTCH, and doxycycline hydrochloride (DCH, respectively. The detection limit was found to be 0.38, 0.75, 1.44 µg mL-1 and the linear range was obtained at 1.0-3.0, 3.0-5.0, and 3.0-10.0 µg mL-1 for TCH, CTCH and DCH, respectively. The proposed method has been successfully applied to the determination of tetracycline antibiotic residues in milk samples. Moreover, this method is an environmentally friendly approach and suitable for routine analysis.

A microfabricated electroosmotic pump coupled to a gas-diffusion microchip for flow injection analysis of ammonia

International Nuclear Information System (INIS)

Zhu, Zaifang; Lu, Joann J.; Liu, Shaorong; Almeida, M. Inês G. S.; Kolev, Spas D.; Pu, Qiaosheng

2015-01-01

We have microfabricated two functional components toward developing a microchip flow injection analysis (FIA) system, i.e., an open-channel electroosmotic pump and a gas-diffusion chip, consisting of two microfabricated glass wafers and a porous polytetrafluoroethylene membrane. This is the first application of gas-diffusion separation in a microchip FIA system. To demonstrate the feasibility of using these two components for performing gas-diffusion FIA, we have incorporated them together with a regular FIA injection valve and a capillary electrophoresis absorbance detector in a flow injection system for determination of ammonia in environmental water samples. This system has a limit of detection of 0.10 mg L −1 NH 3 , with a good repeatability (relative standard deviation of less than 5 % for 4.0 mg L −1 NH 3 ). Parameters affecting its performance are also discussed. (author)

Study of sample-detector assemblies for application to in-situ measurement of radioactivity in liquid effluents

International Nuclear Information System (INIS)

Pendharkar, K.A.; Narayanan Kutty, K.; Krishnamony, S.

1991-01-01

This paper describes the experimental investigations carried out on four different types of sample-detector assemblies with a view to determining their detection limits and relative merits for application to in-situ measurement of radioactivity in liquid effluents. The four systems studied were: (1) gamma detection using 11 cm x 8 cm NaI (Tl) scintillation detector inserted in the cavity of a specially designed stainless steel chamber of capacity 15 liters, (2) gamma detection using a metal-walled G.M. counter in a similar manner, (3) beta detection using twin thin-walled G.M. counters immersed in liquid, and (4) end window G.M. counter positioned above the liquid surface in a shallow tray. The design features of an in-line monitor employing a 11 cm x 8 cm NaI (Tl) detector used for the routine monitoring of beta gamma activity concentrations in the low level effluents of the Tarapur Fuel Processing Plant are described. (author). 1 tab

Microbiological analyses of samples from the H-Area injection well test site

International Nuclear Information System (INIS)

Wilde, E.W.; Franck, M.M.

1997-01-01

Microbial populations in well water from monitoring wells at the test site were one to three orders of magnitude higher than well water from the Cretaceous aquifer (used as dilution water for the tests) or from a control well adjacent to the test site facility. Coupons samples placed in monitoring and control wells demonstrated progressive adhesion by microbes to materials used in well construction. Samples of material scraped from test well components during abandonment of the test site project revealed the presence of a variety of attached microbes including iron bacteria. Although the injection wells at the actual remediation facility for the F- and H-Area seepage basins remediation project are expected to be subjected to somewhat different conditions (e.g. considerably lower iron concentrations) than was the case at the test site, the potential for microbiologically mediated clogging and fouling within the process should be considered. A sampling program that includes microbiological testing is highly recommended

Vapor permeation-stepwise injection simultaneous determination of methanol and ethanol in biodiesel with voltammetric detection.

Science.gov (United States)

Shishov, Andrey; Penkova, Anastasia; Zabrodin, Andrey; Nikolaev, Konstantin; Dmitrenko, Maria; Ermakov, Sergey; Bulatov, Andrey

2016-02-01

A novel vapor permeation-stepwise injection (VP-SWI) method for the determination of methanol and ethanol in biodiesel samples is discussed. In the current study, stepwise injection analysis was successfully combined with voltammetric detection and vapor permeation. This method is based on the separation of methanol and ethanol from a sample using a vapor permeation module (VPM) with a selective polymer membrane based on poly(phenylene isophtalamide) (PA) containing high amounts of a residual solvent. After the evaporation into the headspace of the VPM, methanol and ethanol were transported, by gas bubbling, through a PA membrane to a mixing chamber equipped with a voltammetric detector. Ethanol was selectively detected at +0.19 V, and both compounds were detected at +1.20 V. Current subtractions (using a correction factor) were used for the selective determination of methanol. A linear range between 0.05 and 0.5% (m/m) was established for each analyte. The limits of detection were estimated at 0.02% (m/m) for ethanol and methanol. The sample throughput was 5 samples h(-1). The method was successfully applied to the analysis of biodiesel samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparison of Detector Technologies for CAPS

Science.gov (United States)

Stockum, Jana L.

2005-01-01

In this paper, several different detectors are examined for use in a Comet/Asteroid Protection System (CAPS), a conceptual study for a possible future space-based system. Each detector will be examined for its future (25 years or more in the future) ability to find and track near-Earth Objects (NEOs) from a space-based detection platform. Within the CAPS study are several teams of people who each focus on different aspects of the system concept. This study s focus is on detection devices. In particular, evaluations on the following devices have been made: charge-coupled devices (CCDs), charge-injected devices (CIDs), superconducting tunneling junctions (STJs), and transition edge sensors (TESs). These devices can be separated into two main categories; the first category includes detectors that are currently being widely utilized, such as CCDs and CIDs. The second category includes experimental detectors, such as STJs and TESs. After the discussion of the detectors themselves, there will be a section devoted to the explicit use of these detectors with CAPS.

Enhancement of superconducting critical current by injection of quasiparticles in superconductor semiconductor devices

DEFF Research Database (Denmark)

Kutchinsky, Jonatan; Taboryski, Rafael Jozef; Sørensen, C. B.

2000-01-01

We report new measurements on 3-terminal superconductor semiconductor injection devices, demonstrating enhancement of the supercurrent by injection from a superconducting injector electrode. Two other electrodes were used as detectors. Applying a small voltage to the injector, reduced the maximum...

Optoelectronic iron detectors for pharmaceutical flow analysis.

Science.gov (United States)

Rybkowska, Natalia; Koncki, Robert; Strzelak, Kamil

2017-10-25

Compact flow-through optoelectronic detectors fabricated by pairing of light emitting diodes have been applied for development of economic flow analysis systems dedicated for iron ions determination. Three analytical methods with different chromogens selectively recognizing iron ions have been compared. Ferrozine and ferene S based methods offer higher sensitivity and slightly lower detection limits than method with 1,10-phenantroline, but narrower ranges of linear response. Each system allows detection of iron in micromolar range of concentration with comparable sample throughput (20 injections per hour). The developed flow analysis systems have been successfully applied for determination of iron in diet supplements. The utility of developed analytical systems for iron release studies from drug formulations has also been demonstrated. Copyright © 2017 Elsevier B.V. All rights reserved.

18F-FDG positron autoradiography with a particle counting silicon pixel detector.

Science.gov (United States)

Russo, P; Lauria, A; Mettivier, G; Montesi, M C; Marotta, M; Aloj, L; Lastoria, S

2008-11-07

We report on tests of a room-temperature particle counting silicon pixel detector of the Medipix2 series as the detector unit of a positron autoradiography (AR) system, for samples labelled with (18)F-FDG radiopharmaceutical used in PET studies. The silicon detector (1.98 cm(2) sensitive area, 300 microm thick) has high intrinsic resolution (55 microm pitch) and works by counting all hits in a pixel above a certain energy threshold. The present work extends the detector characterization with (18)F-FDG of a previous paper. We analysed the system's linearity, dynamic range, sensitivity, background count rate, noise, and its imaging performance on biological samples. Tests have been performed in the laboratory with (18)F-FDG drops (37-37 000 Bq initial activity) and ex vivo in a rat injected with 88.8 MBq of (18)F-FDG. Particles interacting in the detector volume produced a hit in a cluster of pixels whose mean size was 4.3 pixels/event at 11 keV threshold and 2.2 pixels/event at 37 keV threshold. Results show a sensitivity for beta(+) of 0.377 cps Bq(-1), a dynamic range of at least five orders of magnitude and a lower detection limit of 0.0015 Bq mm(-2). Real-time (18)F-FDG positron AR images have been obtained in 500-1000 s exposure time of thin (10-20 microm) slices of a rat brain and compared with 20 h film autoradiography of adjacent slices. The analysis of the image contrast and signal-to-noise ratio in a rat brain slice indicated that Poisson noise-limited imaging can be approached in short (e.g. 100 s) exposures, with approximately 100 Bq slice activity, and that the silicon pixel detector produced a higher image quality than film-based AR.

Effects of large volume injection of aliphatic alcohols as sample diluents on the retention of low hydrophobic solutes in reversed-phase liquid chromatography.

Science.gov (United States)

David, Victor; Galaon, Toma; Aboul-Enein, Hassan Y

2014-01-03

Recent studies showed that injection of large volume of hydrophobic solvents used as sample diluents could be applied in reversed-phase liquid chromatography (RP-LC). This study reports a systematic research focused on the influence of a series of aliphatic alcohols (from methanol to 1-octanol) on the retention process in RP-LC, when large volumes of sample are injected on the column. Several model analytes with low hydrophobic character were studied by RP-LC process, for mobile phases containing methanol or acetonitrile as organic modifiers in different proportions with aqueous component. It was found that starting with 1-butanol, the aliphatic alcohols can be used as sample solvents and they can be injected in high volumes, but they may influence the retention factor and peak shape of the dissolved solutes. The dependence of the retention factor of the studied analytes on the injection volume of these alcohols is linear, with a decrease of its value as the sample volume is increased. The retention process in case of injecting up to 200μL of upper alcohols is dependent also on the content of the organic modifier (methanol or acetonitrile) in mobile phase. Copyright © 2013 Elsevier B.V. All rights reserved.

The 150 ns detector project: progress with small detectors

International Nuclear Information System (INIS)

Warburton, W.K.; Russell, S.R.; Kleinfelder, Stuart A.; Segal, Julie

1994-01-01

This project's long term goal is to develop a pixel area detector capable of 6 MHz frame rates (150 ns/frame). Our milestones toward this goal are: a single pixel, 1x256 1D and 8x8 2D detectors, 256x256 2D detectors and, finally, 1024x1024 2D detectors. The design strategy is to supply a complete electronics chain (resetting preamp, selectable gain amplifier, analog-to-digital converter (ADC), and memory) for each pixel. In the final detectors these will all be custom integrated circuits. The front end preamplifiers are being integrated first, since their design and performance are both the most unusual and also critical to the project's success. Similarly, our early work is also concentrating on devising and perfecting detector structures which are thick enough (1 mm) to absorb over 99% of the incident X-rays in the energy range of interest. In this paper we discuss our progress toward the 1x256 1D and 8x8 2D detectors. We have fabricated sample detectors at Stanford's Center for Integrated Systems and are preparing both to test them individually and to wirebond them to the preamplifier samples to produce our first working small 1D and 2D detectors. We will describe our solutions to the design problems associated with collecting charge in less than 30 ns from 1 mm thick pixels in high resistivity silicon. We have constructed and tested the front end of our preamplifier design using a commercial 1.2 μm CMOS technology and are moving on to produce a few channels of the complete preamplifier, including a switchable gain stage and output stage. We will discuss both the preamplifier design and our initial test results. ((orig.))

The 150 ns detector project: progress with small detectors

Energy Technology Data Exchange (ETDEWEB)

Warburton, W.K. (X-ray Instrumentation Associates, 2513 Charleston Rd, Ste 207, Mountain View, CA 94043 (United States)); Russell, S.R. (X-ray Instrumentation Associates, 2513 Charleston Rd, Ste 207, Mountain View, CA 94043 (United States)); Kleinfelder, Stuart A. (VLSI Physics, 19 Drury Lane, Berkeley, CA 94705 (United States)); Segal, Julie (Integrated Ckts Lab., Dept. of Electrical Engineering, Stanford University, Stanford, CA 94305 (United States))

1994-09-01

This project's long term goal is to develop a pixel area detector capable of 6 MHz frame rates (150 ns/frame). Our milestones toward this goal are: a single pixel, 1x256 1D and 8x8 2D detectors, 256x256 2D detectors and, finally, 1024x1024 2D detectors. The design strategy is to supply a complete electronics chain (resetting preamp, selectable gain amplifier, analog-to-digital converter (ADC), and memory) for each pixel. In the final detectors these will all be custom integrated circuits. The front end preamplifiers are being integrated first, since their design and performance are both the most unusual and also critical to the project's success. Similarly, our early work is also concentrating on devising and perfecting detector structures which are thick enough (1 mm) to absorb over 99% of the incident X-rays in the energy range of interest. In this paper we discuss our progress toward the 1x256 1D and 8x8 2D detectors. We have fabricated sample detectors at Stanford's Center for Integrated Systems and are preparing both to test them individually and to wirebond them to the preamplifier samples to produce our first working small 1D and 2D detectors. We will describe our solutions to the design problems associated with collecting charge in less than 30 ns from 1 mm thick pixels in high resistivity silicon. We have constructed and tested the front end of our preamplifier design using a commercial 1.2 [mu]m CMOS technology and are moving on to produce a few channels of the complete preamplifier, including a switchable gain stage and output stage. We will discuss both the preamplifier design and our initial test results. ((orig.))

Calibration, monitoring, and control of complex detector systems

International Nuclear Information System (INIS)

Breidenbach, M.

1981-01-01

LEP detectors will probably be complex devices having tens of subsystems; some subsystems having perhaps tens of thousands of channels. Reasonable design goals for such a detector will include economic use of money and people, rapid and reliable calibration and monitoring of the detector, and simple control and operation of the device. The synchronous operation of an e + e - storage ring, coupled with its relatively low interaction rate, allow the design of simple circuits for time and charge measurements. These circuits, and more importantly, the basic detector channels, can usually be tested and calibrated by signal injection into the detector. Present detectors utilize semi-autonomous controllers which collect such calibration data and calculate statistics as well as control sparse data scans. Straightforward improvements in programming technology should move the entire calibration into these local controllers, so that calibration and testing time will be a constant independent of the number of channels in a system. Considerable programming effort may be saved by emphasizing the similarities of the subsystems, so that the subsystems can be described by a reasonable database and general purpose calibration and test routines can be used. Monitoring of the apparatus will probably continue to be of two classes: 'passive' histogramming of channel occupancies and other more complex combinations of the data; and 'active' injection of test patterns and calibration signals during a run. The relative importance of active monitoring will increase for the low data rates expected off resonances at high s. Experience at SPEAR and PEP is used to illustrate these approaches. (Auth.)

Calibration, Monitoring, and Control of Complex Detector Systems

Science.gov (United States)

Breidenbach, M.

1981-04-01

LEP Detectors will probably be complex devices having tens of subsystems; some subsystems having perhaps tens of thousands of channels. Reasonable design goals for such a detector will include economic use of money and people, rapid and reliable calibration and monitoring of the detector, and simple control and operation of the device. The synchronous operation of an e+e- storage ring, coupled with its relatively low interaction rate, allow the design of simple circuits for time and charge measurements. These circuits, and more importantly, the basic detector channels, can usually be tested and calibrated by signal injection into the detector. Present detectors utilize semi-autonomous controllers which collect such calibration data and calculate statistics as well as control sparse data scans. Straightforward improvements in programming technology should move the entire calibration into these local controllers, so that calibration and testing time will be a constant independent of the number of channels in a system. Considerable programming effort may be saved by emphasizing the similarities of the subsystems, so that the subsystems can be described by a reasonable database and general purpose calibration and test routines can be used. Monitoring of the apparatus will probably continue to be of two classes: "passive" histogramming of channel occupancies and other more complex combinations of the data; and "active" injection of test patterns and calibration signals during a run. The relative importance of active monitoring will increase for the low data rates expected off resonances at high s. Experience at SPEAR and PEP is used to illustrate these approaches.

Development of sample assay system equipped with 3He Alternative Neutron Detectors (ASAS). (2) Results of ASAS measurement test

International Nuclear Information System (INIS)

Tanigawa, Masafumi; Mukai, Yasunobu; Kurita, Tsutomu; Makino, Risa; Nakamura, Hironobu; Tobita, Hiroshi; Ohzu, Akira; Kureta, Masatoshi; Seya, Michio

2015-01-01

Against the background of the serious shortage of 3 He gas, design and development of a new detector equipped ZnS/ 10 B 2 O 3 ceramic scintillation neutron detectors in JAEA, with the support of the government (the Ministry of Education, Culture, Sports, Science and Technology). The design of the alternative 3 He detector is referred from INVS (INVentory Sample assay system (HLNCC (High Level Neutron Coincidence Counter) type)) which is being used for the verification of MOX powder etc. and is named it as ASAS (Alternative Sample Assay System). In order to prove the Pu quantitative performance as an alternative technology, several measurement tests and comparison test with INVS were conducted using ASAS. In these tests, evaluation of fundamental performance (counting efficiency and die-away time) and uncertainty evaluations were implemented. As a result, although fundamental performance of ASAS was not achieved to the one of INVS, we could confirm that ASAS has almost the same Pu quantitative performance including measurement uncertainty as that of INVS. (author)

Detection of fission fragments using thick samples in contact with solid state nuclear track detectors

International Nuclear Information System (INIS)

Lima, D.A. de; Martins, J.B.; Tavares, O.A.P.

1987-01-01

Whenever use is made of thick samples in contact with solid state nuclear track detectors for determining fission yields, one of the fundamental problems is the evaluation of the effective number of target nuclei which contributes to the fraction of the number of fission events that will be recorded. The evaluation of the effective number of target nuclei which contributes to recorded events is based on the effective thickness of the sample. A method for evaluating effective thickness of thick samples for binary fission modes, is presented. A cross section equation which takes into account all the necessary corrections due to fragment attenuation effects by a thick target for calculation induced fission yields, was obtained. (Author) [pt

Amorphous silicon radiation detectors

Science.gov (United States)

Street, Robert A.; Perez-Mendez, Victor; Kaplan, Selig N.

1992-01-01

Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification.

Detector for failed fuel elements

International Nuclear Information System (INIS)

Ito, Masaru.

1979-01-01

Purpose: To provide automatic monitor for the separation or reactor water and sampling water, in a failed fuel element detector using a sipping chamber. Constitution: A positional detector for the exact mounting of a sipping chamber on a channel box and a level detector for the detection of complete discharge of cooling water in the sipping chamber are provided in the sipping chamber. The positional detector is contacted to the upper end of the channel box and operated when the sipping chamber is correctly mounted to the fuel assemblies. The level detector comprises a float and a limit switch and it is operated when the water in the sipping chamber is discharged by a predetermined amount. Isolation of reactor water and sampling water are automatically monitored by the signal from these two detectors. (Ikeda, J.)

Patterns of drug use among a sample of drug users and injecting drug users attending a General Practice in Iran

Directory of Open Access Journals (Sweden)

Shakeshaft Anthony

2006-01-01

Full Text Available Abstract Aim This study aimed to examine drug use, drug treatment history and risk behaviour among a sample of Iranian drug users seeking treatment through a general practice clinic in Iran. Methods Review of medical records and an intake questionnaire at a large general practice in Marvdasht, Iran, with a special interest in drug dependence treatment. Records from a random sample of injecting drug users (IDU, non-injecting drug users (DU and non-drug using patients were examined. Results 292 records were reviewed (34% IDU, 31% DU and 35% non-drug users. Eighty-three percent were males; all females were non-drug users. The mean age of the sample was 30 years. Of the IDU sample, 67% reported sharing a needle or syringe, 19% of these had done so in prison. Of those who had ever used drugs, being 'tired' of drug use was the most common reason for seeking help (34%. Mean age of first drug use was 20 years. The first drugs most commonly used were opium (72%, heroin (13% and hashish/ other cannabinoids (13%. Three quarters reported having previously attempted to cease their drug use. IDU were more likely than DU to report having ever been imprisoned (41% vs 7% and 41% to have used drugs in prison. Conclusion This study has shown that there is a need for general practice clinics in Iran to treat drug users including those who inject and that a substantial proportion of those who inject have shared needles and syringes, placing them at risk of BBVI such as HIV and hepatitis C. The expansion of services for drug users in Iran such as needle and syringe programs and pharmacotherapies are likely to be effective in reducing the harms associated with opium use and heroin injection.

Radiometric detection in flow-injection analysis; Radiometric flow-injection analysis

Energy Technology Data Exchange (ETDEWEB)

Myint, U; Han, B; Myoe, K M; Kywe, A; Thida, [Yangon Univ. (Myanmar). Dept. of Chemistry; Toelgyessy, J [Slovak Technical Univ., Braatislava (Slovakia). Dept. of Environmental Science

1994-05-17

A single line system with a detector of radioactivity was used for the determination of [sup 60]Co. In the determination, no additional chemistry is involved and limited dispersion is desirable. For this application, the FIA system is used only as a transport system for the sample up to the detector. (author) 7 refs.; 4 figs.

High accuracy injection circuit for the calibration of a large pixel sensor matrix

International Nuclear Information System (INIS)

Quartieri, E.; Comotti, D.; Manghisoni, M.

2013-01-01

Semiconductor pixel detectors, for particle tracking and vertexing in high energy physics experiments as well as for X-ray imaging, in particular for synchrotron light sources and XFELs, require a large area sensor matrix. This work will discuss the design and the characterization of a high-linearity, low dispersion injection circuit to be used for pixel-level calibration of detector readout electronics in a large pixel sensor matrix. The circuit provides a useful tool for the characterization of the readout electronics of the pixel cell unit for both monolithic active pixel sensors and hybrid pixel detectors. In the latter case, the circuit allows for precise analogue test of the readout channel already at the chip level, when no sensor is connected. Moreover, it provides a simple means for calibration of readout electronics once the detector has been connected to the chip. Two injection techniques can be provided by the circuit: one for a charge sensitive amplification and the other for a transresistance readout channel. The aim of the paper is to describe the architecture and the design guidelines of the calibration circuit, which has been implemented in a 130 nm CMOS technology. Moreover, experimental results of the proposed injection circuit will be presented in terms of linearity and dispersion

Segmentation of the Outer Contact on P-Type Coaxial Germanium Detectors

Energy Technology Data Exchange (ETDEWEB)

Hull, Ethan L.; Pehl, Richard H.; Lathrop, James R.; Martin, Gregory N.; Mashburn, R. B.; Miley, Harry S.; Aalseth, Craig E.; Hossbach, Todd W.

2006-09-21

Germanium detector arrays are needed for low-level counting facilities. The practical applications of such user facilities include characterization of low-level radioactive samples. In addition, the same detector arrays can also perform important fundamental physics measurements including the search for rare events like neutrino-less double-beta decay. Coaxial germanium detectors having segmented outer contacts will provide the next level of sensitivity improvement in low background measurements. The segmented outer detector contact allows performance of advanced pulse shape analysis measurements that provide additional background reduction. Currently, n-type (reverse electrode) germanium coaxial detectors are used whenever a segmented coaxial detector is needed because the outer boron (electron barrier) contact is thin and can be segmented. Coaxial detectors fabricated from p-type germanium cost less, have better resolution, and are larger than n-type coaxial detectors. However, it is difficult to reliably segment p-type coaxial detectors because thick (~1 mm) lithium-diffused (hole barrier) contacts are the standard outside contact for p-type coaxial detectors. During this Phase 1 Small Business Innovation Research (SBIR) we have researched the possibility of using amorphous germanium contacts as a thin outer contact of p-type coaxial detectors that can be segmented. We have developed amorphous germanium contacts that provide a very high hole barrier on small planar detectors. These easily segmented amorphous germanium contacts have been demonstrated to withstand several thousand volts/cm electric fields with no measurable leakage current (<1 pA) from charge injection over the hole barrier. We have also demonstrated that the contact can be sputter deposited around and over the curved outside surface of a small p-type coaxial detector. The amorphous contact has shown good rectification properties on the outside of a small p-type coaxial detector. These encouraging

Use of the femoral vein ('groin injecting' by a sample of needle exchange clients in Bristol, UK

Directory of Open Access Journals (Sweden)

Maliphant John

2005-04-01

Full Text Available Abstract Background Use of the femoral vein for intravenous access by injecting drug users (IDUs (commonly called 'groin injecting' is a practice that is often observed but on which little is written in the literature. The purpose of this study was to describe self-reported data from a sample of groin injectors on the natural history and rationale regarding their groin injecting, to inform future research and the development of appropriate harm reduction strategies. Methods A convenience sample of groin injectors willing to participate in a semi-structured interview were recruited through the Bristol Drugs Project Harm Reduction Service. The interviews were conducted over the period of one week. Data on transition to groin injecting, rationale for use and incidence of problems were collected. Results Forty seven IDUs currently injecting in their femoral vein ('groin' were interviewed, 66% (n = 31 male and 34% (n = 16 female. Their mean age was 31 yrs (range 17 to 50 yrs; SD = 7.7. The mean length of time since first injecting episode was 9.6 yrs (range 6 mths to 30 yrs; SD = 7.0. The mean length of time since use of the groin began was 2.6 years (range 1 mth to 15 yrs; SD = 3.3. The mean length of time between first injection and first use of the groin was 7.0 yrs (SD = 7.0. One person had used no other area for venous access prior to using the groin, nine people had used one, nine people had used two, 10 people had used three, five people had used four and 13 people had used more than four areas. The main reason given for starting to inject in the groin was that 'no other sites were left'. However further discussion identified this meant no other convenient sites were accessible. Practises such as the rotation of injecting sites, as advocated in many harm reduction leaflets, were reported to be difficult and unreliable. The risk of missing the vein and subsequently losing the 'hit' was considered high. Use of the non-dominant hand to administer

An analysis of respondent-driven sampling with injecting drug users in a high HIV prevalent state of India.

Science.gov (United States)

Phukan, Sanjib Kumar; Medhi, Gajendra Kumar; Mahanta, Jagadish; Adhikary, Rajatashuvra; Thongamba, Gay; Paranjape, Ramesh S; Akoijam, Brogen S

2017-07-03

Personal networks are significant social spaces to spread of HIV or other blood-borne infections among hard-to-reach population, viz., injecting drug users, female sex workers, etc. Sharing of infected needles or syringes among drug users is one of the major routes of HIV transmission in Manipur, a high HIV prevalence state in India. This study was carried out to describe the network characteristics and recruitment patterns of injecting drug users and to assess the association of personal network with injecting risky behaviors in Manipur. A total of 821 injecting drug users were recruited into the study using respondent-driven sampling (RDS) from Bishnupur and Churachandpur districts of Manipur; data on demographic characteristics, HIV risk behaviors, and network size were collected from them. Transition probability matrices and homophily indices were used to describe the network characteristics, and recruitment patterns of injecting drug users. Univariate and multivariate binary logistic regression models were performed to analyze the association between the personal networks and sharing of needles or syringes. The average network size was similar in both the districts. Recruitment analysis indicates injecting drug users were mostly engaged in mixed age group setting for injecting practice. Ever married and new injectors showed lack of in-group ties. Younger injecting drug users had mainly recruited older injecting drug users from their personal network. In logistic regression analysis, higher personal network was found to be significantly associated with increased likelihood of injecting risky behaviors. Because of mixed personal network of new injectors and higher network density associated with HIV exposure, older injecting drug users may act as a link for HIV transmission or other blood-borne infections to new injectors and also to their sexual partners. The information from this study may be useful to understanding the network pattern of injecting drug users

A new TXRF vacuum chamber with sample changer for chemical analysis using silicon drift chamber detector

International Nuclear Information System (INIS)

Streli, C.; Wobrauschek, P.; Zoeger, N.; Pepponi, G.

2003-01-01

Full text: Several TXRF spectrometers for chemical analysis as well as for wafer surface analysis are commercially available. But there is no one available for chemical analysis offering the possibility to measure the samples in vacuum conditions. Vacuum of 10 -2 mbar in the sample environment helps to reduce the background due to scattering from air, thus to improve the detection limits as well as to reduce the absorption of low energy fluorescence radiation from low Z elements and extend the elemental range to be measured and removes the Ar lines from the spectrum. The x-ray group of the Atominstitut designed and fabricated a new vacuum chamber for TXRF equipped with a 12 position sample changer from Italstructures, Riva, Italy. The detector used was a 10 mm 2 silicon drift detector (KETEK, Munich, Germany), offering the advantage of electrically cooling, so no LN2 is required. The chamber was designed to be attached to a diffraction tube housing, e.g. with a fine focus Mo-x-ray tube and uses a multilayer monochromator. Spectra are stored by a small AMTEK MCA and control between sample changer and MCA communication is done by a modified AMPTEK software. The performance is expressed in detection limits of 1 pg Rb for Mo Ka excitation with 50 kV, 40 mA excitation conditions, 1000 s lifetime, obtained from a sample containing 600 pg Rb as single element standard. Details on performance, reproducibility and light element excitation and detection are presented. (author)

Muon borehole detector development for use in four-dimensional tomographic density monitoring

Science.gov (United States)

Flygare, Joshua

The increase of CO2 concentrations in the atmosphere and the correlated temperature rise has initiated research into methods of carbon sequestration. One promising possibility is to store CO2 in subsurface reservoirs of porous rock. After injection, the monitoring of the injected CO2 is of paramount importance because the CO2 plume, if escaped, poses health and environmental risks. Traditionally, seismic reflection methods are the chosen method of determining changes in the reservoir density due to CO2 injection, but this is expensive and not continuous. A potential and promising alternative is to use cosmic muon tomography to determine density changes in the reservoir over a period of time. The work I have completed was the development of a muon detector that will be capable of being deployed in boreholes and perform long-term tomography of the reservoir of interest. The detector has the required dimensions, an angular resolution of approximately 2 degrees, and is robust enough to survive the caustic nature of the fluids in boreholes, as well as temperature and pressure fluctuations. The detector design is based on polystyrene scintillating rods arrayed in alternating layers. The layers, as arranged, can provide four-dimensional (4D) tomographic data to detect small changes in density at depths up to approximately 2 kilometers. Geant4, a Monte Carlo simulation code, was used to develop and optimize the detector design. Additionally, I developed a method of determining the muon flux at depth, including CO2 saturation changes in subsurface reservoirs. Preliminary experiments were performed at Pacific Northwest National Laboratory. This thesis will show the simulations I performed to determine the angular resolution and background discrimination required of the detector, the experiments to determine light transport through the polystyrene scintillating rods and fibers, and the method developed to predict muon flux changes at depth expected after injection.

Tritium depth profiling in carbon samples from fusion experiments

International Nuclear Information System (INIS)

Friedrich, M.; Pilz, W.; Sun, G.; Behrisch, R.; Garcia-Rosales, C.; Bekris, N.; Penzhorn, R.-D.

2000-01-01

Tritium depth profiling by accelerator mass spectrometry has been performed at the Rossendorf 3 MV Tandetron. Tritium particles are counted after the accelerator using a semiconductor detector, while deuterium and other light elements are simultaneously measured with the Faraday cup between the injection magnet and the accelerator. Depth profiles have been measured in carbon samples cut from the first wall tiles of the Garching fusion experiment ASDEX-Upgrade and of the European fusion experiment JET, Culham/UK. Tritium contents in the JET samples were up to six orders higher than in samples from ASDEX-Upgrade. Tritium beam currents from samples with high tritium content were measured partly in the Faraday cup before the accelerator. A dedicated tritium AMS facility with an air-insulated 100 kV tandem accelerator is under construction

Sampling theorem for geometric moment determination and its application to a laser beam position detector.

Science.gov (United States)

Loce, R P; Jodoin, R E

1990-09-10

Using the tools of Fourier analysis, a sampling requirement is derived that assures that sufficient information is contained within the samples of a distribution to calculate accurately geometric moments of that distribution. The derivation follows the standard textbook derivation of the Whittaker-Shannon sampling theorem, which is used for reconstruction, but further insight leads to a coarser minimum sampling interval for moment determination. The need for fewer samples to determine moments agrees with intuition since less information should be required to determine a characteristic of a distribution compared with that required to construct the distribution. A formula for calculation of the moments from these samples is also derived. A numerical analysis is performed to quantify the accuracy of the calculated first moment for practical nonideal sampling conditions. The theory is applied to a high speed laser beam position detector, which uses the normalized first moment to measure raster line positional accuracy in a laser printer. The effects of the laser irradiance profile, sampling aperture, number of samples acquired, quantization, and noise are taken into account.

The Edinburgh Addiction Cohort: recruitment and follow-up of a primary care based sample of injection drug users and non drug-injecting controls

Directory of Open Access Journals (Sweden)

Kimber Jo

2010-02-01

(available from 1981 onwards on general acute inpatient and day cases, mental health inpatient and day cases and cancer was provided by Information Services, NHS Scotland, for all cases interviewed and all dead cases. The Scottish Prison Service provided records for 198 (46% of cases interviewed, 48 cases not interviewed and 34 (18% of dead cases. For a sub-sample of 100 interviewees a search of the Lothian and Borders police database was made for official criminal records and 94 had criminal records. Data linkage for controls is ongoing. Conclusions Injecting drug users recruited from a community setting can be successfully followed-up through interviews and record linkage. Information from injecting cases is being analysed in terms of injecting patterns and possible influences on these. Comparisons between cases and controls will allow identification of possibly modifiable early life risk factors for drug injection and will also clarify the burden of disease associated with injection and the influence on this of different health and social interventions.

Patterns of drug dependence in a Queensland (Australia) sample of Indigenous and non-Indigenous people who inject drugs.

Science.gov (United States)

Smirnov, Andrew; Kemp, Robert; Ward, James; Henderson, Suzanna; Williams, Sidney; Dev, Abhilash; Najman, Jake M

2016-09-01

Despite over-representation of Indigenous Australians in sentinel studies of injecting drug use, little is known about relevant patterns of drug use and dependence. This study compares drug dependence and possible contributing factors in Indigenous and non-Indigenous Australians who inject drugs. Respondent-driven sampling was used in major cities and 'peer recruitment' in regional towns of Queensland to obtain a community sample of Indigenous (n = 282) and non-Indigenous (n = 267) injectors. Data are cross sectional. Multinomial models were developed for each group to examine types of dependence on injected drugs (no dependence, methamphetamine-dependent only, opioid-dependent only, dependent on methamphetamine and opioids). Around one-fifth of Indigenous and non-Indigenous injectors were dependent on both methamphetamine and opioids in the previous 12 months. Psychological distress was associated with dual dependence on these drugs for Indigenous [adjusted relative risk (ARR) 4.86, 95% confidence interval (CI) 2.08-11.34] and non-Indigenous (ARR 4.14, 95% CI 1.59-10.78) participants. Unemployment (ARR 8.98, 95% CI 2.25-35.82) and repeated (> once) incarceration as an adult (ARR 3.78, 95% CI 1.43-9.97) were associated with dual dependence for Indigenous participants only. Indigenous participants had high rates of alcohol dependence, except for those dependent on opioids only. The drug dependence patterns of Indigenous and non-Indigenous people who inject drugs were similar, including the proportions dependent on both methamphetamine and opioids. However, for Indigenous injectors, there was a stronger association between drug dependence and contextual factors such as unemployment and incarceration. Expansion of treatment options and community-level programs may be required. [Smirnov A, Kemp R, Ward J, Henderson S, Williams S, Dev A, Najman J M. Patterns of drug dependence in a Queensland (Australia) sample of Indigenous and non-Indigenous people who

Determination of boron in natural water and products derived from grape using an automated flow injection analysis system with piezoelectric detection

International Nuclear Information System (INIS)

Jesus, Dosil P. de; Saito, Renata M.; Lago, Claudimir L. do

2004-01-01

An automated flow injection analysis system with piezoelectric detection is proposed as a sensitive and selective method for boron. The detector is an electrode-separated piezoelectric quartz crystal coated with N-methyl-D-glucamine-modified poly(epichlorohydrin). The film ability to retain boron allows the adjustment of the linear dynamic range and the sensitivity by varying the injected sample volume. In the present work, the sample volumes were varied from 0.5 to 5.0 mL. Among several ionic species, germanate is the only one that can interfere in the method. Nevertheless, it can be eliminated by addition of sulfide to the sample. The method was successfully applied to the determination of boron concentration in samples of natural water (from 1.71 to 309 μL -1 ) and products derived from grape juice (from 2.06 to 6.21 mg L -1 ). A pretreatment with hydrogen peroxide in alkaline medium was required due to the great amount of sugars in the grape products (author)

A novel muon detector for borehole density tomography

Science.gov (United States)

Bonneville, Alain; Kouzes, Richard T.; Yamaoka, Jared; Rowe, Charlotte; Guardincerri, Elena; Durham, J. Matthew; Morris, Christopher L.; Poulson, Daniel C.; Plaud-Ramos, Kenie; Morley, Deborah J.; Bacon, Jeffrey D.; Bynes, James; Cercillieux, Julien; Ketter, Chris; Le, Khanh; Mostafanezhad, Isar; Varner, Gary; Flygare, Joshua; Lintereur, Azaree T.

2017-04-01

Muons can be used to image the density of materials through which they pass, including geological structures. Subsurface applications of the technology include tracking fluid migration during injection or production, with increasing concern regarding such timely issues as induced seismicity or chemical leakage into aquifers. Current density monitoring options include gravimetric data collection and active or passive seismic surveys. One alternative, or complement, to these methods is the development of a muon detector that is sufficiently compact and robust for deployment in a borehole. Such a muon detector can enable imaging of density structure to monitor small changes in density - a proxy for fluid migration - at depths up to 1500 m. Such a detector has been developed, and Monte Carlo modeling methods applied to simulate the anticipated detector response. Testing and measurements using a prototype detector in the laboratory and shallow underground laboratory demonstrated robust response. A satisfactory comparison with a large drift tube-based muon detector is also presented.

A Novel Immune-Inspired Shellcode Detection Algorithm Based on Hyperellipsoid Detectors

Directory of Open Access Journals (Sweden)

Tianliang Lu

2018-01-01

Full Text Available Shellcodes are machine language codes injected into target programs in the form of network packets or malformed files. Shellcodes can trigger buffer overflow vulnerability and execute malicious instructions. Signature matching technology used by antivirus software or intrusion detection system has low detection rate for unknown or polymorphic shellcodes; to solve such problem, an immune-inspired shellcode detection algorithm was proposed, named ISDA. Static analysis and dynamic analysis were both applied. The shellcodes were disassembled to assembly instructions during static analysis and, for dynamic analysis, the API function sequences of shellcodes were obtained by simulation execution to get the behavioral features of polymorphic shellcodes. The extracted features of shellcodes were encoded to antigens based on n-gram model. Immature detectors become mature after immune tolerance based on negative selection algorithm. To improve nonself space coverage rate, the immune detectors were encoded to hyperellipsoids. To generate better antibody offspring, the detectors were optimized through clonal selection algorithm with genetic mutation. Finally, shellcode samples were collected and tested, and result shows that the proposed method has higher detection accuracy for both nonencoded and polymorphic shellcodes.

Sequential Injection Determination of D-Glucose by Chemiluminescence Using an Open Tubular Immobilised Enzyme Reactor

DEFF Research Database (Denmark)

Liu, Xuezhu; Hansen, Elo Harald

1996-01-01

A sequential injection analysis system is described that incorporates a nylon tubular reactor containing immobilised glucose oxidase, allowing determination of D-glucose by means of subsequent luminol chemiluminescence detection of the hydrogen peroxide generated in the enzymatic reaction....... The operating parameters were optimised by fractional factorial screening and response surface modelling. The linear range of D-glucose determination was 30-600 mu M, With a detection limit of 15 mu M using a photodiode detector. The sampling frequency was 54 h(-1). Lower LOD (0.5 mu M D-glucose) could...

Porous media investigation before and after hydrochloric acid injection on a pre-salt carbonate coquinas sample.

Science.gov (United States)

Machado, A C; Teles, A P; Pepin, A; Bize-Forest, N; Lima, I; Lopes, R T

2016-04-01

Porous space characterization of carbonate rocks is an important aid in petroleum exploration from carbonate reservoir. In this study, X-ray microtomography technique was applied to evaluate total porosity of a coquina sample extracted from pre-salt reservoir, in Brazil, before and after acid injection. Two image processing program were used in order to assess performance. The results showed that microtomography has potential to compute porosity of coquina samples and provides information about rock porous network. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mechanical Properties Distribution within Polypropylene Injection Molded Samples: Effect of Mold Temperature under Uneven Thermal Conditions

Directory of Open Access Journals (Sweden)

Sara Liparoti

2017-11-01

Full Text Available The quality of the polymer parts produced by injection molding is strongly affected by the processing conditions. Uncontrolled deviations from the proper process parameters could significantly affect both internal structure and final material properties. In this work, to mimic an uneven temperature field, a strong asymmetric heating is applied during the production of injection-molded polypropylene samples. The morphology of the samples is characterized by optical and atomic force microscopy (AFM, whereas the distribution of mechanical modulus at different scales is obtained by Indentation and HarmoniX AFM tests. Results clearly show that the temperature differences between the two mold surfaces significantly affect the morphology distributions of the molded parts. This is due to both the uneven temperature field evolutions and to the asymmetric flow field. The final mechanical property distributions are determined by competition between the local molecular stretch and the local structuring achieved during solidification. The cooling rate changes affect internal structures in terms of relaxation/reorganization levels and give rise to an asymmetric distribution of mechanical properties.

Calibration of germanium detectors

International Nuclear Information System (INIS)

Bjurman, B.; Erlandsson, B.

1985-01-01

This paper describes problems concerning the calibration of germanium detectors for the measurement of gamma-radiation from environmental samples. It also contains a brief description of some ways of reducing the uncertainties concerning the activity determination. These uncertainties have many sources, such as counting statistics, full energy peak efficiency determination, density correction and radionuclide specific-coincidence effects, when environmental samples are investigated at close source-to-detector distances

Diagnosing the PEP-II Injection System

Energy Technology Data Exchange (ETDEWEB)

Decker, F.-J.; Donald, M.H.; Iverson, R.H.; Kulikov, A.; Pappas, G.C.; Weaver, M.; /SLAC

2005-05-09

The injection of beam into the PEP-II B-Factory, especially into the High Energy Ring (HER) has some challenges. A high background level in the BaBar detector has for a while inhibited us from trickling charge into the HER similar to the Low Energy Ring (LER). Analyzing the injection system has revealed many issues which could be improved. The injection bump between two kickers was not closed, mainly because the phase advance wasn't exactly 180{sup o} and the two kicker strengths were not balanced. Additionally we found reflections which kick the stored beam after the main kick and cause the average luminosity to drop about 3% for a 10 Hz injection rate. The strength of the overall kick is nearly twice as high as the design, indicating a much bigger effective septum thickness. Compared with single beam the background is worse when the HER beam is colliding with the LER beam. This hints that the beam-beam force and the observed vertical blow-up in the HER pushes the beam and especially the injected beam further out to the edge of the dynamic aperture or beyond.

Diagnosing the PEP-II Injection System

International Nuclear Information System (INIS)

Decker, F.-J.; Donald, M.H.; Iverson, R.H.; Kulikov, A.; Pappas, G.C.; Weaver, M.; SLAC

2005-01-01

The injection of beam into the PEP-II B-Factory, especially into the High Energy Ring (HER) has some challenges. A high background level in the BaBar detector has for a while inhibited us from trickling charge into the HER similar to the Low Energy Ring (LER). Analyzing the injection system has revealed many issues which could be improved. The injection bump between two kickers was not closed, mainly because the phase advance wasn't exactly 180 o and the two kicker strengths were not balanced. Additionally we found reflections which kick the stored beam after the main kick and cause the average luminosity to drop about 3% for a 10 Hz injection rate. The strength of the overall kick is nearly twice as high as the design, indicating a much bigger effective septum thickness. Compared with single beam the background is worse when the HER beam is colliding with the LER beam. This hints that the beam-beam force and the observed vertical blow-up in the HER pushes the beam and especially the injected beam further out to the edge of the dynamic aperture or beyond

Influence of external and internal conditions of detector sample treatment on the particle registration sensitivity of Solid State Nuclear Track Detectors of type CR-39

International Nuclear Information System (INIS)

Hermsdorf, Dietrich

2012-01-01

The sensitivity of charged particle registration with SSNTD is the most important parameter to decide about the applicability of those detectors in research, technology and environmental dosimetry. The sensitivity is strongly influenced by the treatment of detector samples before, during and after the exposure and the final evaluation process by chemical etching. Whereas changes in detection properties by external environmental influences are generally considered, the dependences on the etching conditions are ignored. Commonly the sensitivity is assumed to compensate variations in the etching conditions for track revealing. In the present work the validity of this hypothesis will be checked. In the frame of the existing database the sensitivity is not really independent on variations in etching temperatures and should be corrected for differences in the activation energies for stimulation of the bulk and track etching process. Differences in the concentration dependence may be of minor importance. Furthermore, the registration sensitivity depends on environmental conditions before, during and after the irradiation with particles under investigation. Such external parameters are the air pressure, the sample temperature and modification of bulk material by out-gassing in vacuum and exposure to γ-rays. However, the available database is insufficient and inaccurate to draw final conclusions on the detection properties of SSNTD under various external and internal conditions.

Three Alternative Symbol-Lock Detectors

Science.gov (United States)

Shihabi, Mazen M.; Hinedi, Sami M.; Shah, Biren N.

1993-01-01

Three symbol-lock detectors proposed as alternatives in advanced receivers processing non-return-to-zero binary data signals. Two perform operations similar to those of older square-law and absolute-value types. However, integrals computed during nonoverlapping symbol periods and, therefore, only one integrator needed in each such detector. Proposed detectors simpler, but performances worse because noises in overlapping samples correlated, whereas noises in nonoverlapping samples not correlated. Third detector is signal-power-estimator type. Signal integrated during successive half symbol cycles, and therefore only one integrator needed. Half-cycle integrals multiplied to eliminate effect of symbol polarity, and products accumulated during M-cycle observation period to smooth out estimate of signal power. If estimated signal power exceeds threshold, delta, then lock declared.

Comparison of field-enhanced and pressure-assisted field-enhanced sample injection techniques for the analysis of water-soluble vitamins using CZE.

Science.gov (United States)

Liu, Qingqing; Liu, Yaling; Guan, Yu; Jia, Li

2009-04-01

A new online concentration method, namely pressure-assisted field-enhanced sample injection (PA-FESI), was developed and compared with FESI for the analysis of water-soluble vitamins by CZE with UV detection. In PA-FESI, negative voltage and positive pressure were simultaneously applied to initialize PA-FESI. PA-FESI uses the hydrodynamic flow generated by the positive pressure to counterbalance the reverse EOF in the capillary column during electrokinetic sample injection, which allowed a longer injection time than usual FESI mode without compromising the separation efficiency. Using the PA-FESI method, the LODs of the vitamins were at ng/mL level based on the S/N of 3 and the RSDs of migration time and peak area for each vitamin (1 microg/mL) were less than 5.1%. The developed method was applied to the analysis of water-soluble vitamins in corns.

Theoretical considerations of Flow Injection Analysis in the Absence of Chemical Reactions

DEFF Research Database (Denmark)

Andersen, Jens Enevold Thaulov

2000-01-01

The fundamental mechanism of flow injection analysis (FIA) is assumed to be simple dissusion and the response of the detector is included in a model description that provide information about the shape of the FIA peak in terms of, basically, five parameters. Two of the five parameters are associa...... that any deviation from the features of the present model and the results of a tentative chemical reaction with one of the test compounds, is related to chemical kinetics.......The fundamental mechanism of flow injection analysis (FIA) is assumed to be simple dissusion and the response of the detector is included in a model description that provide information about the shape of the FIA peak in terms of, basically, five parameters. Two of the five parameters...

Cosmic-ray-veto detector system

International Nuclear Information System (INIS)

Miller, D.W.; Menlove, H.O.

1992-12-01

To reduce the cosmic-ray-induced neutron background, we are testing a cosmic-ray veto option with a neutron detector system that uses plastic scintillator slabs mounted on the outside of a 3 He-tube detector. The scintillator slabs eliminate unwanted cosmic-ray events, enabling the detector to assay low-level plutonium samples, for which a low-background coincident signature is critical. This report describes the design and testing of the prototype cosmic-ray-veto detector system

Experimental technique to measure thoron generation rate of building material samples using RAD7 detector

International Nuclear Information System (INIS)

Csige, I.; Szabó, Zs.; Szabó, Cs.

2013-01-01

Thoron ( 220 Rn) is the second most abundant radon isotope in our living environment. In some dwellings it is present in significant amount which calls for its identification and remediation. Indoor thoron originates mainly from building materials. In this work we have developed and tested an experimental technique to measure thoron generation rate in building material samples using RAD7 radon-thoron detector. The mathematical model of the measurement technique provides the thoron concentration response of RAD7 as a function of the sample thickness. For experimental validation of the technique an adobe building material sample was selected for measuring the thoron concentration at nineteen different sample thicknesses. Fitting the parameters of the model to the measurement results, both the generation rate and the diffusion length of thoron was estimated. We have also determined the optimal sample thickness for estimating the thoron generation rate from a single measurement. -- Highlights: • RAD7 is used for the determination of thoron generation rate (emanation). • The described model takes into account the thoron decay and attenuation. • The model describes well the experimental results. • A single point measurement method is offered at a determined sample thickness

Quantification of glibenclamide in cleaning samples of pharmaceutical equipment through high performance liquid chromatography

International Nuclear Information System (INIS)

Baeza Fonte, Alen Nils; Diaz Aguila, Elsa Eneida; Martinez Alfonso; Nancy

2012-01-01

to submit a selective analytical method for quantization of glibenclamide in cleaning samples of pharmaceutical equipment using high performance liquid chromatography. The mobile phase consisted of an equal mixing of acetonitrile/phosphate buffer KH 2 PO 4 ; with 0.037 mol/L concentration pH 5.25 and flow of 1.5 mL/min, in a Nucleosil 100 C8 column. Glibenclamide was injected with progesterone as internal standard and using an UV detector= 230 nm

CVD diamond detectors for ionizing radiation

Science.gov (United States)

Friedl, M.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; van Eijk, B.; Fallou, A.; Fizzotti, F.; Foulon, F.; Gan, K. K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Knöpfle, K. T.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P. F.; Manfredotti, C.; Marshall, R. D.; Meier, D.; Mishina, M.; Oh, A.; Pan, L. S.; Palmieri, V. G.; Pernegger, H.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Pretzl, K.; Re, V.; Riester, J. L.; Roe, S.; Roff, D.; Rudge, A.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Tapper, R. J.; Tesarek, R.; Thomson, G. B.; Trawick, M.; Trischuk, W.; Vittone, E.; Walsh, A. M.; Wedenig, R.; Weilhammer, P.; Ziock, H.; Zoeller, M.; RD42 Collaboration

1999-10-01

In future HEP accelerators, such as the LHC (CERN), detectors and electronics in the vertex region of the experiments will suffer from extreme radiation. Thus radiation hardness is required for both detectors and electronics to survive in this harsh environment. CVD diamond, which is investigated by the RD42 Collaboration at CERN, can meet these requirements. Samples of up to 2×4 cm2 have been grown and refined for better charge collection properties, which are measured with a β source or in a testbeam. A large number of diamond samples has been irradiated with hadrons to fluences of up to 5×10 15 cm-2 to study the effects of radiation. Both strip and pixel detectors were prepared in various geometries. Samples with strip metallization have been tested with both slow and fast readout electronics, and the first diamond pixel detector proved fully functional with LHC electronics.

Development of a sequential injection-square wave voltammetry method for determination of paraquat in water samples employing the hanging mercury drop electrode.

Science.gov (United States)

dos Santos, Luciana B O; Infante, Carlos M C; Masini, Jorge C

2010-03-01

This work describes the development and optimization of a sequential injection method to automate the determination of paraquat by square-wave voltammetry employing a hanging mercury drop electrode. Automation by sequential injection enhanced the sampling throughput, improving the sensitivity and precision of the measurements as a consequence of the highly reproducible and efficient conditions of mass transport of the analyte toward the electrode surface. For instance, 212 analyses can be made per hour if the sample/standard solution is prepared off-line and the sequential injection system is used just to inject the solution towards the flow cell. In-line sample conditioning reduces the sampling frequency to 44 h(-1). Experiments were performed in 0.10 M NaCl, which was the carrier solution, using a frequency of 200 Hz, a pulse height of 25 mV, a potential step of 2 mV, and a flow rate of 100 µL s(-1). For a concentration range between 0.010 and 0.25 mg L(-1), the current (i(p), µA) read at the potential corresponding to the peak maximum fitted the following linear equation with the paraquat concentration (mg L(-1)): i(p) = (-20.5 ± 0.3)C (paraquat) - (0.02 ± 0.03). The limits of detection and quantification were 2.0 and 7.0 µg L(-1), respectively. The accuracy of the method was evaluated by recovery studies using spiked water samples that were also analyzed by molecular absorption spectrophotometry after reduction of paraquat with sodium dithionite in an alkaline medium. No evidence of statistically significant differences between the two methods was observed at the 95% confidence level.

Noise, sampling, and the number of projections in cone-beam CT with a flat-panel detector

International Nuclear Information System (INIS)

Zhao, Z.; Gang, G. J.; Siewerdsen, J. H.

2014-01-01

Purpose: To investigate the effect of the number of projection views on image noise in cone-beam CT (CBCT) with a flat-panel detector. Methods: This fairly fundamental consideration in CBCT system design and operation was addressed experimentally (using a phantom presenting a uniform medium as well as statistically motivated “clutter”) and theoretically (using a cascaded systems model describing CBCT noise) to elucidate the contributing factors of quantum noise (σ Q ), electronic noise (σ E ), and view aliasing (σ view ). Analysis included investigation of the noise, noise-power spectrum, and modulation transfer function as a function of the number of projections (N proj ), dose (D tot ), and voxel size (b vox ). Results: The results reveal a nonmonotonic relationship between image noise andN proj at fixed total dose: for the CBCT system considered, noise decreased with increasing N proj due to reduction of view sampling effects in the regime N proj proj due to increased electronic noise. View sampling effects were shown to depend on the heterogeneity of the object in a direct analytical relationship to power-law anatomical clutter of the form κ/f  β —and a general model of individual noise components (σ Q , σ E , and σ view ) demonstrated agreement with measurements over a broad range in N proj , D tot , and b vox . Conclusions: The work elucidates fairly basic elements of CBCT noise in a manner that demonstrates the role of distinct noise components (viz., quantum, electronic, and view sampling noise). For configurations fairly typical of CBCT with a flat-panel detector (FPD), the analysis reveals a “sweet spot” (i.e., minimum noise) in the rangeN proj ∼ 250–350, nearly an order of magnitude lower in N proj than typical of multidetector CT, owing to the relatively high electronic noise in FPDs. The analysis explicitly relates view aliasing and quantum noise in a manner that includes aspects of the object (“clutter”) and imaging chain

Performance of a Small Anode Germanium Well detector

International Nuclear Information System (INIS)

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

2015-01-01

The performance of Small Anode Germanium (SAGe) Well detector [1] has been evaluated for a range of sample sizes and geometries counted inside the well, on the end cap or in Marinelli beakers. The SAGe Well is a new type of low capacitance germanium well detector manufactured using small anode technology. The detector has similar energy resolution performance to semi-planar detectors, and offers significant improvement over the Coaxial and existing Well detectors. Resolution performance of 0.75 keV Full Width at Half Maxiumum (FWHM) at 122 keV γ-ray energy and resolution of 2.0–2.3 keV FWHM at 1332 keV γ-ray energy are guaranteed. 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. This paper reports the counting performance of SAGe Well detector for range of sample sizes and geometries and how it compares to other detector types

Performance of a Small Anode Germanium Well detector

Energy Technology Data Exchange (ETDEWEB)

Adekola, A.S., E-mail: aderemi.adekola@canberra.com; Colaresi, J.; Douwen, J.; Mueller, W.F.; Yocum, K.M.

2015-06-01

The performance of Small Anode Germanium (SAGe) Well detector [1] has been evaluated for a range of sample sizes and geometries counted inside the well, on the end cap or in Marinelli beakers. The SAGe Well is a new type of low capacitance germanium well detector manufactured using small anode technology. The detector has similar energy resolution performance to semi-planar detectors, and offers significant improvement over the Coaxial and existing Well detectors. Resolution performance of 0.75 keV Full Width at Half Maxiumum (FWHM) at 122 keV γ-ray energy and resolution of 2.0–2.3 keV FWHM at 1332 keV γ-ray energy are guaranteed. 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. This paper reports the counting performance of SAGe Well detector for range of sample sizes and geometries and how it compares to other detector types.

Characterization of silicon detectors through TCT at Delhi University

Energy Technology Data Exchange (ETDEWEB)

Jain, G., E-mail: geetikajain.hep@gmail.com; Lalwani, K.; Dalal, R.; Bhardwaj, A.; Ranjan, K.

2016-07-11

Transient Current Technique (TCT) is one of the important methods to characterize silicon detectors and is based on the time evolution of the charge carriers generated when a laser light is shone on it. For red laser, charge is injected only to a small distance from the surface of the detector. For such a system, one of the charge carriers is collected faster than the readout time of the electronics and therefore, the effective signal at the electrodes is decided by the charge carriers that traverse throughout the active volume of the detector, giving insight to the electric field profile, drift velocity, effective doping density, etc. of the detector. Delhi University is actively involved in the silicon detector R&D and has recently installed a TCT setup consisting of a red laser system, a Faraday cage, a SMU (Source Measuring Unit), a bias tee, and an amplifier. Measurements on a few silicon pad detectors have been performed using the developed system, and the results have been found in good agreement with the CERN setup.

Characterization of silicon detectors through TCT at Delhi University

International Nuclear Information System (INIS)

Jain, G.; Lalwani, K.; Dalal, R.; Bhardwaj, A.; Ranjan, K.

2016-01-01

Transient Current Technique (TCT) is one of the important methods to characterize silicon detectors and is based on the time evolution of the charge carriers generated when a laser light is shone on it. For red laser, charge is injected only to a small distance from the surface of the detector. For such a system, one of the charge carriers is collected faster than the readout time of the electronics and therefore, the effective signal at the electrodes is decided by the charge carriers that traverse throughout the active volume of the detector, giving insight to the electric field profile, drift velocity, effective doping density, etc. of the detector. Delhi University is actively involved in the silicon detector R&D and has recently installed a TCT setup consisting of a red laser system, a Faraday cage, a SMU (Source Measuring Unit), a bias tee, and an amplifier. Measurements on a few silicon pad detectors have been performed using the developed system, and the results have been found in good agreement with the CERN setup.

Characterization of silicon detectors through TCT at Delhi University

Science.gov (United States)

Jain, G.; Lalwani, K.; Dalal, R.; Bhardwaj, A.; Ranjan, K.

2016-07-01

Transient Current Technique (TCT) is one of the important methods to characterize silicon detectors and is based on the time evolution of the charge carriers generated when a laser light is shone on it. For red laser, charge is injected only to a small distance from the surface of the detector. For such a system, one of the charge carriers is collected faster than the readout time of the electronics and therefore, the effective signal at the electrodes is decided by the charge carriers that traverse throughout the active volume of the detector, giving insight to the electric field profile, drift velocity, effective doping density, etc. of the detector. Delhi University is actively involved in the silicon detector R&D and has recently installed a TCT setup consisting of a red laser system, a Faraday cage, a SMU (Source Measuring Unit), a bias tee, and an amplifier. Measurements on a few silicon pad detectors have been performed using the developed system, and the results have been found in good agreement with the CERN setup.

Hadronic interactions in the MINOS detectors

Energy Technology Data Exchange (ETDEWEB)

Kordosky, Michael Alan [Univ. of Texas, Austin, TX (United States)

2004-08-01

MINOS, the Main Injector Neutrino Oscillation Search, will study neutrino flavor transformations using a Near detector at the Fermi National Accelerator Laboratory and a Far detector located in the Soudan Underground Laboratory in northern Minnesota. The MINOS collaboration also constructed the CalDet (calibration detector), a smaller version of the Near and Far detectors, to determine the topological and signal response to hadrons, electrons and muons. The detector was exposed to test-beams in the CERN Proton Synchrotron East Hall during 2001-2003, where it collected events at momentum settings between 200 MeV/c and 10 GeV/c. In this dissertation we present results of the CalDet experiment, focusing on the topological and signal response to hadrons. We briefly describe the MINOS experiment and its iron-scintillator tracking-sampling calorimters as a motivation for the CalDet experiment. We discuss the operation of the CalDet in the beamlines as well as the trigger and particle identification systems used to isolate the hadron sample. The method used to calibrate the MINOS detector is described and validated with test-beam data. The test-beams were simulated to model the muon flux, energy loss upstream of the detector and the kaon background. We describe the procedure used to discriminate between pions and muons on the basis of the event topology. The hadron samples were used to benchmark the existing GEANT3 based hadronic shower codes and determine the detector response and resolution for pions and protons. We conclude with comments on the response to single hadrons and to neutrino induced hadronic showers.

Study of the gamma spectrum of 16N with a BGO detector, for the purpose of calibration and of determining the fluorine grade of mineral samples

International Nuclear Information System (INIS)

Castro-Garcia, M.P.; Alonso-Sanchez, T.; Rey-Ronco, M.A.

2013-01-01

The study of 16 N's gamma spectrum has two main uses: calibrating gamma detectors in a high energy range, and determining the fluorine grade of mineral samples of fluorite. This article examines and compares the gamma ray spectrum of 16 N as recorded by a Bi 4 GeO 12 detector, as well as the resolution of this detector at high energy levels, and the signal-background relationship of an experimental laboratory cyclic activation unit. 16 N is the product of the reaction 9-F-19(n,α)7-N-16, which takes place during the neutron activation of mineral samples of fluorspar, and its production depends, among other factors, upon the grade of fluorite. The technique used in this study is cyclic-type neutron activation for recording delayed gamma rays, carried out with an americium-beryllium neutron source with an activity of 1 Ci. Lastly, a correlation is established between the area below the peak amount of 16 N emitted by the sample, and the sample's fluorite grade. (author)

Quantitative portable gamma spectroscopy sample analysis for non-standard sample geometries

International Nuclear Information System (INIS)

Enghauser, M.W.; Ebara, S.B.

1997-01-01

Utilizing a portable spectroscopy system, a quantitative method for analysis of samples containing a mixture of fission and activation products in nonstandard geometries was developed. The method can be used with various sample and shielding configurations where analysis on a laboratory based gamma spectroscopy system is impractical. The portable gamma spectroscopy method involves calibration of the detector and modeling of the sample and shielding to identify and quantify the radionuclides present in the sample. The method utilizes the intrinsic efficiency of the detector and the unattenuated gamma fluence rate at the detector surface per unit activity from the sample to calculate the nuclide activity and Minimum Detectable Activity (MDA). For a complex geometry, a computer code written for shielding applications (MICROSHIELD) is utilized to determine the unattenuated gamma fluence rate per unit activity at the detector surface. Lastly, the method is only applicable to nuclides which emit gamma rays and cannot be used for pure beta emitters. In addition, if sample self absorption and shielding is significant, the attenuation will result in high MDA's for nuclides which solely emit low energy gamma rays. The following presents the analysis technique and presents verification results demonstrating the accuracy of the method

Comparison of Microbial Community Compositions of Injection and Production Well Samples in a Long-Term Water-Flooded Petroleum Reservoir

Science.gov (United States)

Ren, Hong-Yan; Zhang, Xiao-Jun; Song, Zhi-yong; Rupert, Wieger; Gao, Guang-Jun; Guo, Sheng-xue; Zhao, Li-Ping

2011-01-01

Water flooding plays an important role in recovering oil from depleted petroleum reservoirs. Exactly how the microbial communities of production wells are affected by microorganisms introduced with injected water has previously not been adequately studied. Using denaturing gradient gel electrophoresis (DGGE) approach and 16S rRNA gene clone library analysis, the comparison of microbial communities is carried out between one injection water and two production waters collected from a working block of the water-flooded Gudao petroleum reservoir located in the Yellow River Delta. DGGE fingerprints showed that the similarities of the bacterial communities between the injection water and production waters were lower than between the two production waters. It was also observed that the archaeal composition among these three samples showed no significant difference. Analysis of the 16S rRNA gene clone libraries showed that the dominant groups within the injection water were Betaproteobacteria, Gammaproteobacteria and Methanomicrobia, while the dominant groups in the production waters were Gammaproteobacteria and Methanobacteria. Only 2 out of 54 bacterial operational taxonomic units (OTUs) and 5 out of 17 archaeal OTUs in the injection water were detected in the production waters, indicating that most of the microorganisms introduced by the injection water may not survive to be detected in the production waters. Additionally, there were 55.6% and 82.6% unique OTUs in the two production waters respectively, suggesting that each production well has its specific microbial composition, despite both wells being flooded with the same injection water. PMID:21858049

CVD diamond detectors for ionizing radiation

CERN Document Server

Friedl, M; Bauer, C; Berfermann, E; Bergonzo, P; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Conway, J; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Gan, K K; Gheeraert, E; Grigoriev, E; Hallewell, G D; Hall-Wilton, R; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Karl, C; Kass, R; Knöpfle, K T; Krammer, Manfred; Lo Giudice, A; Lü, R; Manfredi, P F; Manfredotti, C; Marshall, R D; Meier, D; Mishina, M; Oh, A; Pan, L S; Palmieri, V G; Pernegger, H; Pernicka, Manfred; Peitz, A; Pirollo, S; Polesello, P; Pretzl, Klaus P; Re, V; Riester, J L; Roe, S; Roff, D G; Rudge, A; Schnetzer, S R; Sciortino, S; Speziali, V; Stelzer, H; Stone, R; Tapper, R J; Tesarek, R J; Thomson, G B; Trawick, M L; Trischuk, W; Vittone, E; Walsh, A M; Wedenig, R; Weilhammer, Peter; Ziock, H J; Zöller, M

1999-01-01

In future HEP accelerators, such as the LHC (CERN), detectors and electronics in the vertex region of the experiments will suffer from extreme radiation. Thus radiation hardness is required for both detectors and electronics to survive in this harsh environment. CVD diamond, which is investigated by the RD42 Collaboration at CERN, can meet these requirements. Samples of up to 2*4 cm/sup 2/ have been grown and refined for better charge collection properties, which are measured with a beta source or in a test beam. A large number of diamond samples has been irradiated with hadrons to fluences of up to 5*10/sup 15/ cm/sup -2/ to study the effects of radiation. Both strip and pixel detectors were prepared in various geometries. Samples with strip metallization have been tested with both slow and fast readout electronics, and the first diamond pixel detector proved fully functional with LHC electronics. (16 refs).

CVD diamond detectors for ionizing radiation

Energy Technology Data Exchange (ETDEWEB)

Friedl, M. E-mail: markus.friedl@cern.ch; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P.F.; Manfredotti, C.; Marshall, R.D.; Meier, D.; Mishina, M.; Oh, A.; Pan, L.S.; Palmieri, V.G.; Pernegger, H.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Pretzl, K.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Tapper, R.J.; Tesarek, R.; Thomson, G.B.; Trawick, M.; Trischuk, W.; Vittone, E.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Ziock, H.; Zoeller, M

1999-10-01

In future HEP accelerators, such as the LHC (CERN), detectors and electronics in the vertex region of the experiments will suffer from extreme radiation. Thus radiation hardness is required for both detectors and electronics to survive in this harsh environment. CVD diamond, which is investigated by the RD42 Collaboration at CERN, can meet these requirements. Samples of up to 2x4 cm{sup 2} have been grown and refined for better charge collection properties, which are measured with a {beta} source or in a test beam. A large number of diamond samples has been irradiated with hadrons to fluences of up to 5x10{sup 15} cm{sup -2} to study the effects of radiation. Both strip and pixel detectors were prepared in various geometries. Samples with strip metallization have been tested with both slow and fast readout electronics, and the first diamond pixel detector proved fully functional with LHC electronics. (author)

Confocal laser-induced fluorescence detector for narrow capillary system with yoctomole limit of detection.

Science.gov (United States)

Weaver, Mitchell T; Lynch, Kyle B; Zhu, Zaifang; Chen, Huang; Lu, Joann J; Pu, Qiaosheng; Liu, Shaorong

2017-04-01

Laser-induced fluorescence (LIF) detectors for low-micrometer and sub-micrometer capillary on-column detection are not commercially available. In this paper, we describe in details how to construct a confocal LIF detector to address this issue. We characterize the detector by determining its limit of detection (LOD), linear dynamic range (LDR) and background signal drift; a very low LOD (~70 fluorescein molecules or 12 yoctomole fluorescein), a wide LDR (greater than 3 orders of magnitude) and a small background signal drift (~1.2-fold of the root mean square noise) are obtained. For detecting analytes inside a low-micrometer and sub-micrometer capillary, proper alignment is essential. We present a simple protocol to align the capillary with the optical system and use the position-lock capability of a translation stage to fix the capillary in position during the experiment. To demonstrate the feasibility of using this detector for narrow capillary systems, we build a 2-μm-i.d. capillary flow injection analysis (FIA) system using the newly developed LIF prototype as a detector and obtain an FIA LOD of 14 zeptomole fluorescein. We also separate a DNA ladder sample by bare narrow capillary - hydrodynamic chromatography and use the LIF prototype to monitor the resolved DNA fragments. We obtain not only well-resolved peaks but also the quantitative information of all DNA fragments. Copyright © 2016 Elsevier B.V. All rights reserved.

Polymer fiber detectors for photoacoustic imaging

Science.gov (United States)

Grün, Hubert; Berer, Thomas; Pühringer, Karoline; Nuster, Robert; Paltauf, Günther; Burgholzer, Peter

2010-02-01

Photoacoustic imaging is a novel imaging method for medical and biological applications, combining the advantages of Diffuse Optical Imaging (high contrast) and Ultrasonic Imaging (high spatial resolution). A short laser pulse hits the sample. The absorbed energy causes a thermoelastic expansion and thereby launches a broadband ultrasonic wave (photoacoustic signal). The distribution of absorbed energy density is reconstructed from measurements of the photoacoustic signals around the sample. For collecting photoacoustic signals either point like or extended, integrating detectors can be used. The latter integrate the pressure at least in one dimension, e.g. along a line. Thereby, the three dimensional imaging problem is reduced to a two dimensional problem. For a tomography device consisting of a scanning line detector and a rotating sample, fiber-based detectors made of polymer have been recently introduced. Fiber-based detectors are easy to use and possess a constant, high spatial resolution over their entire active length. Polymer fibers provide a better impedance matching and a better handling compared with glass fibers which were our first approach. First measurement results using polymer fiber detectors and some approaches for improving the performance are presented.

Optimum time of blood sampling for determination of glomerular filtration rate by single-injection [51Cr]EDTA plasma clearance

International Nuclear Information System (INIS)

Broechner-Mortensen, J.; Roedbro, P.

1976-01-01

We have investigated the influence on reproducibility of total [ 51 Cr]EDTA plasma clearance (E) of various times and numbers of blood samples in patients with normal (13 patients) and low (14 patients) renal function. The study aims at fixing a clinically useful procedure suitable for all levels of renal function. Six different types of E were evaluated with time periods for blood sampling between 3 and 5 h after tracer injection, and the variation from counting radioactivity, s 1 , was determined as part of the total variation, s 2 . Optimum mean time, t(E), for blood sampling was calculated as a function of E, as the mean time giving the least change in E for a given change in the 'final slope' of the plasma curve. For patients with normal E, s 1 did not contribute significantly to s 2 , and t(E) was about 2h. For patients with low renal function s 1 contributed significantly to s 2 , and t(E) increased steeply with decreasing E. The relative error in s 1 from fixed Etypes was calculated for all levels of renal function. The results indicate that blood sampling individualized according to predicted E values is not necessary. A sufficient precision of E can be achieved for all function levels from three blood samples drawn at 180, 240, and 300 min after injection. (Auth.)

Detector Sampling of Optical/IR Spectra: How Many Pixels per FWHM?

Science.gov (United States)

Robertson, J. Gordon

2017-08-01

Most optical and IR spectra are now acquired using detectors with finite-width pixels in a square array. Each pixel records the received intensity integrated over its own area, and pixels are separated by the array pitch. This paper examines the effects of such pixellation, using computed simulations to illustrate the effects which most concern the astronomer end-user. It is shown that coarse sampling increases the random noise errors in wavelength by typically 10-20 % at 2 pixels per Full Width at Half Maximum, but with wide variation depending on the functional form of the instrumental Line Spread Function (i.e. the instrumental response to a monochromatic input) and on the pixel phase. If line widths are determined, they are even more strongly affected at low sampling frequencies. However, the noise in fitted peak amplitudes is minimally affected by pixellation, with increases less than about 5%. Pixellation has a substantial but complex effect on the ability to see a relative minimum between two closely spaced peaks (or relative maximum between two absorption lines). The consistent scale of resolving power presented by Robertson to overcome the inadequacy of the Full Width at Half Maximum as a resolution measure is here extended to cover pixellated spectra. The systematic bias errors in wavelength introduced by pixellation, independent of signal/noise ratio, are examined. While they may be negligible for smooth well-sampled symmetric Line Spread Functions, they are very sensitive to asymmetry and high spatial frequency sub-structure. The Modulation Transfer Function for sampled data is shown to give a useful indication of the extent of improperly sampled signal in an Line Spread Function. The common maxim that 2 pixels per Full Width at Half Maximum is the Nyquist limit is incorrect and most Line Spread Functions will exhibit some aliasing at this sample frequency. While 2 pixels per Full Width at Half Maximum is nevertheless often an acceptable minimum for

A SPICE model of double-sided Si microstrip detectors

International Nuclear Information System (INIS)

Candelori, A.; Paccagnella, A.; Bonin, F.

1996-01-01

We have developed a SPICE model for the ohmic side of AC-coupled Si microstrip detectors with interstrip isolation via field plates. The interstrip isolation has been measured in various conditions by varying the field plate voltage. Simulations have been compared with experimental data in order to determine the values of the model parameters for different voltages applied to the field plates. The model is able to predict correctly the frequency dependence of the coupling between adjacent strips. Furthermore, we have used such model for the study of the signal propagation along the detector when a current signal is injected in a strip. Only electrical coupling is considered here, without any contribution due to charge sharing derived from carrier diffusion. For this purpose, the AC pads of the strips have been connected to a read-out electronics and the current signal has been injected into a DC pad. Good agreement between measurements and simulations has been reached for the central strip and the first neighbors. Experimental tests and computer simulations have been performed for four different strip and field plate layouts, in order to investigate how the detector geometry affects the parameters of the SPICE model and the signal propagation

Dedicated detectors for surface studies by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Bibicu, I.; Rogalski, M.S.; Nicolescu, G.

2001-01-01

Moessbauer spectroscopy is a nuclear resonance method largely utilized in solid state studies. Following resonant nuclear absorption, gamma radiations, conversion X-rays, conversion or Auger electrons are emitted. By detection of gamma radiations information about the sample as a whole are obtained while by detection of electrons or X radiation one obtains data on the surface layer. Our laboratory was among the firsts to produce and use flow gas proportional detectors for surface studies by Moessbauer spectroscopy. Four types of detectors were devised: - detectors for electron detection (90% He + 10% CH 4 ); - detectors for conversion X-ray detection (90% Ar + 10% CH 4 ); - detectors for electrons or internal conversion X rays; - detectors for simultaneous detection of electrons and conversion X rays emitted from the same source. All detectors allow simultaneous Moessbauer measurements both for surface and volume for a given sample. Details of construction are presented for the four types of detectors

Pressure-assisted introduction of urine samples into a short capillary for electrophoretic separation with contactless conductivity and UV spectrometry detection.

Science.gov (United States)

Makrlíková, Anna; Opekar, František; Tůma, Petr

2015-08-01

A computer-controlled hydrodynamic sample introduction method has been proposed for short-capillary electrophoresis. In the method, the BGE flushes sample from the loop of a six-way sampling valve and is carried to the injection end of the capillary. A short pressure impulse is generated in the electrolyte stream at the time when the sample zone is at the capillary, leading to injection of the sample into the capillary. Then the electrolyte flow is stopped and the separation voltage is turned on. This way of sample introduction does not involve movement of the capillary and both of its ends remain constantly in the solution during both sample injection and separation. The amount of sample introduced to the capillary is controlled by the duration of the pressure pulse. The new sample introduction method was tested in the determination of ammonia, creatinine, uric acid, and hippuric acid in human urine. The determination was performed in a capillary with an overall length of 10.5 cm, in two BGEs with compositions 50 mM MES + 5 mM NaOH (pH 5.1) and 1 M acetic acid + 1.5 mM crown ether 18-crown-6 (pH 2.4). A dual contactless conductivity/UV spectrometric detector was used for the detection. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Energy-dispersive X-ray fluorescence of discarded tire samples, using a Si-PIN detector

International Nuclear Information System (INIS)

Lopes, Fabio; Appoloni, C.R.; Melquiades, Fabio L.

2007-01-01

The determination of zinc concentration in samples of discarded tires is of great environmental interest because the process for manufacturing tyres uses S for rubber vulcanization, and ZnO is the reaction catalyst. Discarded tyres are being used in asphalt paving, in the burning process of thermoelectric and cement industries and also for controlling erosion in agricultural areas. Analysis of tyre samples usually requires chemical digestion which is slow and expensive. Aiming to eliminate those limitations, this work uses energy-dispersive X-ray fluorescence (EDXRF) with a portable equipment, once it is a simultaneous multi-element analytical technique, requiring minimal sample preparation. Five samples of discarded tyres have been ground and analysed in the form of pastilles, using a mini X-ray tube (Ag target, MO filter, 25 kV/20 μA) for 200 s, and a Si-PIN semiconductor detector coupled to a multichannel analyser. Zinc concentrations in the range of 40.6 to 44.2 μg g -1 have been obtained, representing 0.4% of the tire composition, which is below the maximum value (2%) recommended by the European Tyre Recycling Association. Concentrations between 0.15 and 0.52 μg g -1 were obtained for Fe

New sampling electronics using CCD for DIOGENE: a high multiplicity, 4 π detector for relativistic heavy ions

International Nuclear Information System (INIS)

Babinet, R.P.

1987-01-01

DIOGENE is a small time projection chamber which has been developed to study central collisions of relativistic heavy ions. The maximum multiplicity (up to 40 charged particles) that can be accepted by this detector is limited by the present electronics. In view of the heavier mass ions that should become readily available at the Saturne national facility (France), a new sampling electronics has been tested. In the first part of this talk they will present a brief description of the actual detector, insisting on the performances that have been effectively obtained with α-particles and Neon beams. The motivation for and characteristics of a renewed electronic set-up should thus appear more clearly. The second part of the talk is devoted to results of the tests that have been performed using charged couple devices. They will finally conclude on the future perspectives that have been opened by these developments

A Detector System for Identifying Substances in a Sample

DEFF Research Database (Denmark)

2010-01-01

for illuminating a first area and a second area of the corresponding cantilever (330); a detector array (334, 336), and a receiver diffractive optical element (329) adapted to collect light reflected from the cantilever array and to form at least two spatially overlapping images of said areas so that interference...

Measurement of the $M_A^{QE}$ parameter using multiple quasi-elastic dominated sub-samples in the minos near detector

Energy Technology Data Exchange (ETDEWEB)

Mayer, Nathan Samuel [Indiana Univ., Bloomington, IN (United States)

2011-12-05

The Main Injector Neutrino Oscillation Search (MINOS) is a two detector, long baseline neutrino oscillation experiment. The MINOS near detector is an ironscintillator tracking/sampling calorimeter and has recorded the world’s largest data set of neutrino interactions in the 0-5 GeV region. This high statistics data set is used to make precision measurements of neutrino interaction cross-sections on iron. The Q² dependence in charged current quasi-elastic (CCQE) scattering probes the axial and vector structure (form factor) of the nucleon/nuclear target, and nuclear effects in neutrino scattering. Presented here is a study of the MINOS Data that will introduce a method that improves the existing MINOS CCQE analysis. This analysis uses an additional CCQE dominated sub-sample from a different kinematic region to reduce correlations between fit parameters in the existing MINOS CCQE analysis. The measured value of the axial-vector mass is M^QE _A = 1.312^+0.037 _-0.038(fit)^+0.123 _-0.265(syst.) GeV.

Detection of recombinant EPO in blood and urine samples with EPO WGA MAIIA, IEF and SAR-PAGE after microdose injections.

Science.gov (United States)

Dehnes, Yvette; Shalina, Alexandra; Myrvold, Linda

2013-01-01

The misuse of microdoses of performance enhancing drugs like erythropoietin (EPO) constitutes a major challenge in doping analysis. When injected intravenously, the half-life of recombinant human EPO (rhEPO) like epoetin alfa, beta, and zeta is only a few hours and hence, the window for direct detection of rhEPO in urine is small. In order to investigate the detection window for rhEPO directly in blood and urine with a combined affinity chromatography and lateral flow immunoassay (EPO WGA MAIIA), we recruited nine healthy people who each received six intravenously injected microdoses (7.5 IU/kg) of NeoRecormon (epoetin beta) over a period of three weeks. Blood and urine samples were collected in the days following the injections and analyzed with EPO WGA MAIIA as well as the current validated methods for rhEPO; isoelectric focusing (IEF) and sarcosyl polyacrylamide gel electrophoresis (SAR-PAGE). For samples collected 18 h after a microdose, the sensitivity of the EPO WGA MAIIA assay was 100% in plasma and 87.5% in urine samples at the respective 98% specificity threshold levels. In comparison, the sensitivity in plasma and urine was 75% and 100%, respectively, with IEF, and 87.5% in plasma and 100% in urine when analyzed with SAR-PAGE. We conclude that EPO WGA MAIIA is a sensitive assay for the detection of rhEPO, with the potential of being a fast, supplemental screening assay for use in doping analysis.

Speciation of mercury in fish samples by flow injection catalytic cold vapour atomic absorption spectrometry

International Nuclear Information System (INIS)

Zhang Yanlin; Adeloju, Samuel B.

2012-01-01

Highlights: ► Successful speciation of inorganic and organic Hg with Fe 3+ , Cu 2+ and thiourea as catalysts. ► Best sensitivity enhancement and similar sensitivity for MeHg and Hg 2+ with Fe 3+ . ► Successful use of Hg 2+ as the primary standard for quantification of inorganic and total-Hg. ► Quantitative extraction of Hg and MeHg with 2 M HCl which contained thiourea. ► Integration with FIA for rapid analysis with a sample throughput of 180 h −1 . - Abstract: A rapid flow injection catalytic cold vapour atomic absorption spectrometric (FI-CCV-AAS) method is described for speciation and determination of mercury in biological samples. Varying concentrations of NaBH 4 were employed for mercury vapour generation from inorganic and mixture of inorganic and organic (total) Hg. The presence of Fe 3+ , Cu 2+ and thiourea had catalytic effect on mercury vapour generation from methylmercury (MeHg) and, when together, Cu 2+ and thiourea had synergistic catalytic effect on the vapour generation. Of the two metal ions, Fe 3+ gave the best sensitivity enhancement, achieving the same sensitivity for MeHg and inorganic Hg 2+ . Due to similarity of resulting sensitivity, Hg 2+ was used successfully as a primary standard for quantification of inorganic and total Hg. The catalysis was homogeneous in nature, and it was assumed that the breaking of the C-Hg bond was facilitated by the delocalization of the 5d electron pairs in Hg atom. The extraction of MeHg and inorganic mercury (In-Hg) in fish samples were achieved quantitatively with hydrochloric acid in the presence of thiourea and determined by FI-CCV-AAS. The application of the method to the quantification of mercury species in a fish liver reference material DOLT-4 gave 91.5% and 102.3% recoveries for total and methyl mercury, respectively. The use of flow injection enabled rapid analysis with a sample throughput of 180 h −1 .

CBRid4SQL: A CBR Intrusion Detector for SQL Injection Attacks

Science.gov (United States)

Pinzón, Cristian; Herrero, Álvaro; de Paz, Juan F.; Corchado, Emilio; Bajo, Javier

One of the most serious security threats to recently deployed databases has been the SQL Injection attack. This paper presents an agent specialised in the detection of SQL injection attacks. The agent incorporates a Case-Based Reasoning engine which is equipped with a learning and adaptation capacity for the classification of malicious codes. The agent also incorporates advanced algorithms in the reasoning cycle stages. The reuse phase uses an innovative classification model based on a mixture of a neuronal network together with a Support Vector Machine in order to classify the received SQL queries in the most reliable way. Finally, a visualisation neural technique is incorporated, which notably eases the revision stage carried out by human experts in the case of suspicious queries. The Classifier Agent was tested in a real-traffic case study and its experimental results, which validate the performance of the proposed approach, are presented here.

Silicon Sensors for the Upgrades of the CMS Pixel Detector

CERN Document Server

Centis Vignali, Matteo; Schleper, Peter

2015-01-01

The Compact Muon Solenoid (CMS) is a general purpose detector at the Large Hadron Collider (LHC). The LHC luminosity is constantly increased through upgrades of the accel- erator and its injection chain. Two major upgrades will take place in the next years. The rst upgrade involves the LHC injector chain and allows the collider to achieve a luminosity of about 2 10 34 cm-2 s-1 A further upgrade of the LHC foreseen for 2025 will boost its luminosity to 5 10 34 cm-2 s1. As a consequence of the increased luminosity, the detectors need to be upgraded. In particular, the CMS pixel detector will undergo two upgrades in the next years. The rst upgrade (phase I) consists in the substitution of the current pixel detector in winter 2016/2017. The upgraded pixel detector will implement new readout elec- tronics that allow ecient data taking up to a luminosity of 2 10 34 cm-2s-1,twice as much as the LHC design luminosity. The modules that will constitute the upgraded detector are being produced at dierent institutes. Ham...

Calibration of PM-355 nuclear track detectors for low-energy deuterons

International Nuclear Information System (INIS)

Malinowski, K.; Skladnik-Sadowska, E.; Sadowski, M.J.; Czaus, K.

2008-01-01

A dependence of track diameters on deuteron energy was investigated for PM-355 nuclear track detectors. Deuteron streams were obtained from RPI-IBIS facility at the pulsed injection of deuterium. Mass and energy analysis was performed with a Thomson-type spectrometer and PM-355 samples. An etched deuteron parabola extended from about 20 keV to about 500 keV. The energy resolution of measurements on the parabola at 20 keV was ±0.2keV, and at 500 keV amounted to ±50keV. Accuracy of the determination of deuteron energies decreased for higher energy values. Results are presented in diagrams showing the track diameters as a function of deuteron energy for chosen etching times (1-8 h)

On the evening of June 15, 2008, ALICE physicists saw the first tracks at LHC during the first injection test in transfer line TI 2. The Silicon Pixel detector recorded muon tracks produced in the beam dump near Point 2 of the LHC.

CERN Multimedia

Manzari, Vito

2008-01-01

On the evening of June 15, 2008, ALICE physicists saw the first tracks at LHC during the first injection test in transfer line TI 2. The Silicon Pixel detector recorded muon tracks produced in the beam dump near Point 2 of the LHC

Admittance detector for high impedance systems: design and applications.

Science.gov (United States)

Zhang, Min; Stamos, Brian N; Dasgupta, Purnendu K

2014-12-02

We describe an admittance detector for high impedance systems (small capillary bore and/or low solution specific conductance). Operation in the low frequency range (≤1 kHz, much lower than most relevant publications) provides optimum response to conductance changes in capillaries ≤20 μm in bore. The detector design was based on studies described in a preceding companion paper ( Zhang, M.; Stamos, B. N.; Amornthammarong, N.; Dasgupta, P. K. Anal. Chem. 2014, 8 , DOI 10.1021/ac503245a.). The highest S/N for detecting 100 μM KCl (5.5 μM peak concentration, ∼0.8 μS/cm) injected into water flowing through a capillary of 7.5 μm inner radius (r) was observed at 500-750 Hz. A low bias current operational amplifier in the transimpedance configuration permitted high gain (1 V/nA) to measure pA-nA level currents in the detection cell. Aside from an oscillator, an offset-capable RMS-DC converter formed the complete detection circuitry. Limits of detection (LODs) of KCl scaled inversely with the capillary cross section and were 2.1 and 0.32 μM injected KCl for r = 1 and 2.5 μm capillaries, respectively. When used as a detector on an r = 8 μm bore poly(methyl methacrylate) capillary in a split effluent stream from a suppressed ion chromatograph, the LOD was 27 nM bromide (Vex 22 V p-p), compared to 14 nM observed with a commercial bipolar pulse macroscale conductivity detector with an actively thermostated cell. We also show applications of the detector in electrophoresis in capillaries with r = 1 and 2.5 μm. Efficient heat dissipation permits high concentrations of the background electrolyte and sensitive detection because of efficient electrostacking.

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

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

Characterization of detectors of neutrons from B+ZnS (Ag) as an alternative to 3He detectors

International Nuclear Information System (INIS)

Gonzalez, Juan A.; Suarez, Maria J.; Pujol, Luis; Lorente, Alfredo; Gallego, Eduardo

2013-01-01

The objective of this paper is to present the progress made in the design of prototypes for dynamic detection of neutron detectors based on scintillation of B + ZnS (Ag), which can replace existing 3 He detectors for the detection of illicit traffic of radioactive material and special nuclear material. These detectors B + ZnS (Ag) can be used, together with gamma detectors, PVT and NaI (Tl) also developed in the UPM. Two neutron detectors of different shapes and sizes were characterized using two neutron sources of 241 Am + Be. Were determined depth, overall efficiency, intrinsic efficiency and limit of detection. The results of these tests allow to verify that: 1) two cylindrical detectors B + ZnS (Ag) of 5x68 cm, or 4x15x132 cm rectangular detector can replace the cylindrical detector of 5x180 cm 3 He currently employed in the arcades. 2) the dynamic detection limit obtained is less than 20000 neutrons per second, when the sample becomes 2 m to 2m/s, with a probability of having no false positive or negative of the 99.99% 3) digital electronics eliminates interference from gamma emissions samples when their dose rate in the neutron detector is 65 μSv/h in less than factor 10 - 8, and keeps its detection limit and 4) two cylindrical detectors with two moderators of different thickness, of 25 to 50 mm of high density polyethylene, allow to measure the average energy of the neutrons

A fully automated effervescence assisted dispersive liquid–liquid microextraction based on a stepwise injection system. Determination of antipyrine in saliva samples

Energy Technology Data Exchange (ETDEWEB)

Medinskaia, Kseniia; Vakh, Christina; Aseeva, Darina [Department of Analytical Chemistry, Institute of Chemistry, Saint Petersburg State University, RU-198504 Saint Petersburg (Russian Federation); Andruch, Vasil, E-mail: vasil.andruch@upjs.sk [Department of Analytical Chemistry, University of P.J. Šafárik, SK-04154 Košice (Slovakia); Moskvin, Leonid [Department of Analytical Chemistry, Institute of Chemistry, Saint Petersburg State University, RU-198504 Saint Petersburg (Russian Federation); Bulatov, Andrey, E-mail: bulatov_andrey@mail.ru [Department of Analytical Chemistry, Institute of Chemistry, Saint Petersburg State University, RU-198504 Saint Petersburg (Russian Federation)

2016-01-01

A first attempt to automate the effervescence assisted dispersive liquid–liquid microextraction (EA-DLLME) has been reported. The method is based on the aspiration of a sample and all required aqueous reagents into the stepwise injection analysis (SWIA) manifold, followed by simultaneous counterflow injection of the extraction solvent (dichloromethane), the mixture of the effervescence agent (0.5 mol L{sup −1} Na{sub 2}CO{sub 3}) and the proton donor solution (1 mol L{sup −1} CH{sub 3}COOH). Formation of carbon dioxide microbubbles generated in situ leads to the dispersion of the extraction solvent in the whole aqueous sample and extraction of the analyte into organic phase. Unlike the conventional DLLME, in the case of EA-DLLME, the addition of dispersive solvent, as well as, time consuming centrifugation step for disruption of the cloudy state is avoided. The phase separation was achieved by gentle bubbling of nitrogen stream (2 mL min{sup −1} during 2 min). The performance of the suggested approach is demonstrated by determination of antipyrine in saliva samples. The procedure is based on the derivatization of antipyrine by nitrite-ion followed by EA-DLLME of 4-nitrosoantipyrine and subsequent UV–Vis detection using SWIA manifold. The absorbance of the yellow-colored extract at the wavelength of 345 nm obeys Beer's law in the range of 1.5–100 µmol L{sup −1} of antipyrine in saliva. The LOD, calculated from a blank test based on 3σ, was 0.5 µmol L{sup −1}. - Highlights: • First attempt to automate the effervescence assisted dispersive liquid–liquid microextraction. • Automation based on Stepwise injection analysis manifold in flow batch system. • Counterflow injection of extraction solvent and the effervescence agent. • Phase separation performed by gentle bubbling of nitrogen. • Application for the determination of antipyrine in saliva samples.

A fully automated effervescence assisted dispersive liquid–liquid microextraction based on a stepwise injection system. Determination of antipyrine in saliva samples

International Nuclear Information System (INIS)

Medinskaia, Kseniia; Vakh, Christina; Aseeva, Darina; Andruch, Vasil; Moskvin, Leonid; Bulatov, Andrey

2016-01-01

A first attempt to automate the effervescence assisted dispersive liquid–liquid microextraction (EA-DLLME) has been reported. The method is based on the aspiration of a sample and all required aqueous reagents into the stepwise injection analysis (SWIA) manifold, followed by simultaneous counterflow injection of the extraction solvent (dichloromethane), the mixture of the effervescence agent (0.5 mol L"−"1 Na_2CO_3) and the proton donor solution (1 mol L"−"1 CH_3COOH). Formation of carbon dioxide microbubbles generated in situ leads to the dispersion of the extraction solvent in the whole aqueous sample and extraction of the analyte into organic phase. Unlike the conventional DLLME, in the case of EA-DLLME, the addition of dispersive solvent, as well as, time consuming centrifugation step for disruption of the cloudy state is avoided. The phase separation was achieved by gentle bubbling of nitrogen stream (2 mL min"−"1 during 2 min). The performance of the suggested approach is demonstrated by determination of antipyrine in saliva samples. The procedure is based on the derivatization of antipyrine by nitrite-ion followed by EA-DLLME of 4-nitrosoantipyrine and subsequent UV–Vis detection using SWIA manifold. The absorbance of the yellow-colored extract at the wavelength of 345 nm obeys Beer's law in the range of 1.5–100 µmol L"−"1 of antipyrine in saliva. The LOD, calculated from a blank test based on 3σ, was 0.5 µmol L"−"1. - Highlights: • First attempt to automate the effervescence assisted dispersive liquid–liquid microextraction. • Automation based on Stepwise injection analysis manifold in flow batch system. • Counterflow injection of extraction solvent and the effervescence agent. • Phase separation performed by gentle bubbling of nitrogen. • Application for the determination of antipyrine in saliva samples.

High-throughput liquid-absorption preconcentrator sampling methods

Science.gov (United States)

Zaromb, Solomon

1994-01-01

A system for detecting trace concentrations of an analyte in air includes a preconcentrator for the analyte and an analyte detector. The preconcentrator includes an elongated tubular container comprising a wettable material. The wettable material is continuously wetted with an analyte-sorbing liquid which flows from one part of the container to a lower end. Sampled air flows through the container in contact with the wetted material with a swirling motion which results in efficient transfer of analyte vapors or aerosol particles to the sorbing liquid and preconcentration of traces of analyte in the liquid. The preconcentrated traces of analyte may be either detected within the container or removed therefrom for injection into a separate detection means or for subsequent analysis.

Neutron detector development at Brookhaven

International Nuclear Information System (INIS)

Yu, B.; Harder, J.A.; Mead, J.A.; Radeka, V.; Schaknowski, N.A.; Smith, G.C.

2003-01-01

Two-dimensional thermal neutron detectors have been the subject of research and development at Brookhaven for over 20 years. Based primarily on multi-wire chambers filled with a gas mixture containing 3 He, these detectors have been used in wide-ranging studies of molecular biology and material science samples. At each phase of development, experimenters have sought improvements in key parameters such as position resolution, counting rate, efficiency, solid-angle coverage and stability. A suite of detectors has been developed with sensitive areas ranging from 5x5 to 50x50 cm 2 . These devices incorporate low-noise-position readout and the best position resolution for thermal neutron gas detectors. Recent developments include a 1.5 mx20 cm detector containing multiple segments with continuously sensitive readout, and detectors with unity gain for ultra-high rate capability and long-term stability

F-DDIA: A Framework for Detecting Data Injection Attacks in Nonlinear Cyber-Physical Systems

Directory of Open Access Journals (Sweden)

Jingxuan Wang

2017-01-01

Full Text Available Data injection attacks in a cyber-physical system aim at manipulating a number of measurements to alter the estimated real-time system states. Many researchers recently focus on how to detect such attacks. However, most of the detection methods do not work well for the nonlinear systems. In this paper, we present a compressive sampling methodology to identify the attack, which allows determining how many and which measurement signals are launched. The sparsity feature is used. Generally, our methodology can be applied to both linear and nonlinear systems. The experimental testing, which includes realistic load patterns from NYISO with various attack scenarios in the IEEE 14-bus system, confirms that our detector performs remarkably well.

Evolution of the dispersionless injection boundary associated with substorms

Directory of Open Access Journals (Sweden)

T. Sarris

2005-03-01

Full Text Available One manifestation of energetic particle acceleration during magnetospheric substorms is the sudden appearance of particle injections into the inner magnetosphere, often observed near geosynchronous orbit. Injections that show simultaneous flux increases in all energy ranges of a detector are called dispersionless injections, and are most often observed in a narrow region around local midnight. In these events it is assumed that the satellite is located close to or inside the region where acceleration and/or transport processes are taking place, called the injection region. We present a study of the location, extent and temporal evolution of the injection region, based on simulation results of a model of the expansion of the electric and magnetic fields associated with a substorm. The model simulates the fields during a substorm onset with an electric field and consistent magnetic field pulse that propagates towards the Earth with a decreasing speed. Our simulation shows that the dispersionless injection boundary can be considered coincident with the leading edge of the pulse field, which transports particles toward the Earth across a certain range of local time. Under the same model field, the dispersionless injection boundary shifts eastward for electrons and westward for protons, consistent with the observation results deduced from statistical analysis of multiple spacecraft measurements.

Fuel rod leak detector

International Nuclear Information System (INIS)

Womack, R.E.

1978-01-01

A typical embodiment of the invention detects leaking fuel rods by means of a radiation detector that measures the concentration of xenon-133 ( 133 Xe) within each individual rod. A collimated detector that provides signals related to the energy of incident radiation is aligned with one of the ends of a fuel rod. A statistically significant sample of the gamma radiation (γ-rays) that characterize 133 Xe is accumulated through the detector. The data so accumulated indicates the presence of a concentration of 133 Xe appropriate to a sound fuel rod, or a significantly different concentration that reflects a leaking fuel rod

Reverse flow injection spectrophotometric determination of thiram and nabam fungicides in natural water samples

International Nuclear Information System (INIS)

Asghar, M.; Yaqoob, M.; Nabi, A.

2014-01-01

A reverse flow injection (rFI) spectrophotometric method is reported for determination of thiram and nabam fungicides in natural water samples. The method is based on the reduction of iron(III) in the presence of thiram/nabam in acidic medium at 60 degree C and formation of iron(II)-ferricyanide complex was measured at 790 nm. The limits of detection (3s blank) were 0.01 and 0.05 micro g mL1 for thiram and nabam respectively with a sample throughput of 60 h1. Calibration graphs were linear over the range of 0.02 - 8.0 micro g mL1 (R2 = 0.9999, n = 8) and 0.1 - 30 micro g mL1 (R2 = 0.9982, n = 10) for thiram and nabam with relative standard deviations (RSDs; n = 3) in the range of 0.8 - 1.6% respectively. Experimental parameters and potential interferences were examined. Thiram and nabam were determined in natural water samples using solid-phase extraction (SPE) procedure and recoveries were in the range of 93+-3 - 105+-2% and 87+-4 - 102+-3% respectively. The results obtained were not significantly different compared with a HPLC method. (author)

Detection of dopamine in non-treated urine samples using glassy carbon electrodes modified with PAMAM dendrimer-Pt composites

International Nuclear Information System (INIS)

Garcia, M.G.; Armendariz, G.M.E.; Godinez, Luis A.; Torres, J.; Sepulveda-Guzman, S.; Bustos, E.

2011-01-01

Composites of hydroxyl-terminated PAMAM dendrimers, generation 4.0 (64 peripheral OH groups) containing Pt nanoparticles were synthesized at different reaction times using a microwave reactor. The synthetic procedure resulted in dendrimer encapsulated nanoparticles of Pt (DENs-Pt) of 1.53 ± 0.17 nm diameter that was calculated from transmission electron microscopy, and the Pt nanoparticles had single crystal plane in (1 1 1) orientation determinate by selective area diffraction. Each composite was electrochemically immobilized on a pre-functionalized glassy carbon (GC) electrode that was incorporated as a flow injection amperometric (FIA) detector, for the selective detection and quantification of dopamine (DA) in untreated urine samples. Comparison of the analytical performance of the novel electrochemical detector revealed that the DENs-Pt modified GC electrode with the composite synthesized for 30 min in the microwave reactor, showed the best response for the detection of DA in samples of non-treated urine, being the detection and quantification limits smaller (19 and 9 ppb, respectively) than those corresponding to the naked a GC electrode (846 and 423 ppb, respectively) using the FIA detector. In addition, it was found that this electroanalytical approach suffers minimal matrix effects that arise in the analysis of DA in untreated samples of urine.

Detection of dopamine in non-treated urine samples using glassy carbon electrodes modified with PAMAM dendrimer-Pt composites

Energy Technology Data Exchange (ETDEWEB)

Garcia, M.G. [Laboratory of Bioelectrochemistry, Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, S. C., Parque Tecnologico, Queretaro, Sanfandila, Pedro Escobedo 76703, Queretaro (Mexico); Department of Chemistry, Universidad de Guanajuato, Cerro de la Venada S/N Col. Pueblito de Rocha, 36040 Guanajuato, Gto (Mexico); Armendariz, G.M.E.; Godinez, Luis A.; Torres, J. [Laboratory of Bioelectrochemistry, Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, S. C., Parque Tecnologico, Queretaro, Sanfandila, Pedro Escobedo 76703, Queretaro (Mexico); Sepulveda-Guzman, S. [Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia, Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Universidad, San Nicolas de los Garza, Nuevo Leon, 66451 Nuevo Leon (Mexico); Bustos, E., E-mail: ebustos@cideteq.mx [Laboratory of Bioelectrochemistry, Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, S. C., Parque Tecnologico, Queretaro, Sanfandila, Pedro Escobedo 76703, Queretaro (Mexico)

2011-09-01

Composites of hydroxyl-terminated PAMAM dendrimers, generation 4.0 (64 peripheral OH groups) containing Pt nanoparticles were synthesized at different reaction times using a microwave reactor. The synthetic procedure resulted in dendrimer encapsulated nanoparticles of Pt (DENs-Pt) of 1.53 {+-} 0.17 nm diameter that was calculated from transmission electron microscopy, and the Pt nanoparticles had single crystal plane in (1 1 1) orientation determinate by selective area diffraction. Each composite was electrochemically immobilized on a pre-functionalized glassy carbon (GC) electrode that was incorporated as a flow injection amperometric (FIA) detector, for the selective detection and quantification of dopamine (DA) in untreated urine samples. Comparison of the analytical performance of the novel electrochemical detector revealed that the DENs-Pt modified GC electrode with the composite synthesized for 30 min in the microwave reactor, showed the best response for the detection of DA in samples of non-treated urine, being the detection and quantification limits smaller (19 and 9 ppb, respectively) than those corresponding to the naked a GC electrode (846 and 423 ppb, respectively) using the FIA detector. In addition, it was found that this electroanalytical approach suffers minimal matrix effects that arise in the analysis of DA in untreated samples of urine.

Injection Related Background due to the Transverse Feedback

International Nuclear Information System (INIS)

Decker, F.J.; Akre, R.; Fisher, A.; Iverson, R.; Weaver, M.

2008-01-01

The background in the BaBar detector is especially high during injection, when most components are actually having reduced voltages. The situation is worse for the beam in High Energy Ring (HER) when the LER beam is present. It was found that the transverse feedback system plays an important role when stacking more charge on top of existing bunches. Lowering the feedback gain helped and it was realized later that the best scenario would be to gate off the feedback for only the one bunch, which got additional charge injected into it. The explanation is that the blown-up, but centered, original HER bunch plus the small injected off-axis bunch (each with half the charge) would stay in the ring if not touched, but the feedback system sees half the offset and wants to correct it, therefore disturbing and scraping the blown-up part

Development of optimized detector/spectrophotometer technology for low background space astronomy missions

Science.gov (United States)

Jones, B.

1985-01-01

This program was directed towards a better understanding of some of the important factors in the performance of infrared detector arrays at low background conditions appropriate for space astronomy. The arrays were manufactured by Aerojet Electrosystems Corporation, Azusa. Two arrays, both bismuth doped silicon, were investigated: an AMCID 32x32 Engineering mosiac Si:Bi accumulation mode charge injection device detector array and a metal oxide semiconductor/field effect transistor (MOS-FET) switched array of 16x32 pixels.

Epidemiology of HIV and hepatitis C infection among women who inject drugs in Northeast India: a respondent-driven sampling study.

Science.gov (United States)

McFall, Allison M; Solomon, Sunil S; Lucas, Greg M; Celentano, David D; Srikrishnan, Aylur K; Kumar, Muniratnam S; Mehta, Shruti H

2017-08-01

Despite extensive research on HIV and hepatitis C (HCV) among people who inject drugs (PWID), there remains a gap in knowledge on the burden among women who inject drugs and their unique contexts and risk factors. This analysis compares HIV and HCV prevalence in female and male PWID and estimates injection and sexual risk correlates of prevalent HIV and HCV infection among women in Northeast India. Cross-sectional sample accrued using respondent-driven sampling. Seven cities in Northeast India, 2013. A total of 6457 adult PWID. Participants completed an interviewer-administered survey. HIV infection was diagnosed on-site and HCV antibody testing was performed on stored specimens. HIV and HCV prevalence estimates were stratified by gender. Among women, the association of risk correlates with HIV and HCV were estimated using multi-level logistic regression models. A total of 796 (15.9%) of the PWID were women, of whom 52.9% [95% confidence interval (CI) = 49.3-56.5%] were HIV-infected and 22.3% (CI = 19.9-24.7%) were HCV-infected. HIV and HCV prevalence among men was 17.4% (CI = 16.9-24.7%) and 30.4% (CI = 31.2-32.0%), respectively. Among women, correlates of HIV were widowhood [adjusted odds ratio (aOR) versus currently married = 4.03, CI = 2.13-7.60] and a higher number of life-time sexual partners (aOR ≥8 versus none = 3.08, CI = 1.07-8.86). Correlates of HCV were longer injection duration (aOR per 10 years = 1.70, CI = 1.25-2.27), injecting only heroin and a combination of drugs (aOR versus pharmaceuticals only = 5.63, CI = 1.68-18.9 and aOR = 2.58, CI = 1.60-4.16, respectively), sharing needles/syringes (aOR = 2.46, CI = 1.29-4.56) and a larger PWID network (aOR ≥ 51 versus 1-5 = 4.17, CI = 2.43-7.17). Women who inject drugs in Northeast India have a high HIV prevalence, which was more than double their hepatitis C (HCV) prevalence, an opposite pattern than is observed typically among male PWID. HIV infection is

Dual-phase gas-permeation flow-injection thermometric analysis for the determination of carbon dioxide.

Science.gov (United States)

Liu, S J; Tubino, M

1998-11-01

A flow-injection configuration based on a dual-phase gas-permeation system from a liquid donor to a gas acceptor stream with a thermistor flow-through detector is proposed for the direct analysis of the gas in the acceptor. This system was applied for the determination of carbon dioxide (in the form of carbonate) using the following chemical reaction: CO(2)(g)+2NH(3)(g)+H(2)O(g)=(NH(4))(2)CO(3)(s), with a linear response from 1x10(-3) to 50x10(-3) mol l(-1) of CO(3)(2-). Carbon dioxide was produced in the liquid donor and permeated into the gaseous acceptor stream of air/water vapor. The detection limit is 1x10(-3) mol l(-1) of carbonate, and a sampling frequency of 60 h(-1) is achieved with a relative standard deviation of 4.1% for replicate injections. The dual-phase gas-permeation flow-injection manifold, along with the membrane and phase separations, as well as the chemical reaction, provides enhanced selectivity when compared with the system employing a liquid acceptor stream, as serious interferents in this system, for instance, acetate and formate, among others, do not interfere in the proposed system.

Sample extraction and injection with a microscale preconcentrator.

Energy Technology Data Exchange (ETDEWEB)

Robinson, Alex Lockwood (Advanced Sensor Technologies, Albuquerque, NM); Chan, Helena Kai Lun

2007-09-01

This report details the development of a microfabricated preconcentrator that functions as a fully integrated chemical extractor-injector for a microscale gas chromatograph (GC). The device enables parts-per-billion detection and quantitative analysis of volatile organic compounds (VOCs) in indoor air with size and power advantages over macro-scale systems. The 44 mm{sup 3} preconcentrator extracts VOCs using highly adsorptive, granular forms of graphitized carbon black and carbon molecular sieves. The micron-sized silicon cavities have integrated heating and temperature sensing allowing low power, yet rapid heating to thermally desorb the collected VOCs (GC injection). The keys to device construction are a new adsorbent-solvent filling technique and solvent-tolerant wafer-level silicon-gold eutectic bonding technology. The product is the first granular adsorbent preconcentrator integrated at the wafer level. Other advantages include exhaustive VOC extraction and injection peak widths an order of magnitude narrower than predecessor prototypes. A mass transfer model, the first for any microscale preconcentrator, is developed to describe both adsorption and desorption behaviors. The physically intuitive model uses implicit and explicit finite differences to numerically solve the required partial differential equations. The model is applied to the adsorption and desorption of decane at various concentrations to extract Langmuir adsorption isotherm parameters from effluent curve measurements where properties are unknown a priori.

On-line monitoring of Glucose and penicillin by sequential injection analysis

DEFF Research Database (Denmark)

Min, R.W.; Nielsen, Jens Bredal; Villadsen, John

1996-01-01

and a detector. The glucose analyzer is based on an enzymatic reaction using glucose oxidase, which converts glucose to glucono-lactone with formation of hydrogen peroxide and subsequent detection of H2O2 by a chemiluminescence reaction involving luminol. The penicillin analysis is based on formation......A sequential injection analysis (SIA) system has been developed for on-line monitoring of glucose and penicillin during cultivations of the filamentous fungus Penicillium chrysogenum. The SIA system consists of a peristaltic pump, an injection valve, two piston pumps, two multi-position valves...

Prevalence of injections and knowledge of safe injections among rural residents in Central China.

Science.gov (United States)

Yan, Y W; Yan, J; Zhang, G P; Gao, Z L; Jian, H X

2007-08-01

Abuse of the injection services, namely unnecessary injections and unsafe injections, exists extensively in developing countries. Unsafe injection practices contribute to the transmission of blood-borne pathogens. The aims of this study were to survey the prevalence of injections and knowledge of injection safety among the rural residents in Jingzhou district, Hubei, China and to provide scientific data for developing a health educational programme. A retrospective cross-sectional study was conducted in 12 villages, which were selected from the Jingzhou district by the random sampling method. 50 rural residents were interviewed per village using a questionnaire. Among the 595 residents studied, 192 had received at least one injection in the past three months, with an injection prevalence of 32.3 percent and an average of 0.93 injections. 90.3 percent of the rural residents knew that unsafe injections could transmit the following blood-borne pathogens: human immunodeficiency virus (74.4 percent), hepatitis B virus (55.8 percent) and hepatitis C virus (22.9 percent). Logistic regression analysis showed that the residents' age, educational level and residential area were important factors in influencing their knowledge about injection safety. The results indicated that the injection prevalence was high among rural residents in the study area, and their knowledge regarding injection safety should be further improved.

Ultra trace determination of 31 pesticides in water samples by direct injection-rapid resolution liquid chromatography-electrospray tandem mass spectrometry.

Science.gov (United States)

Díaz, Laura; Llorca-Pórcel, Julio; Valor, Ignacio

2008-08-22

A liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method for the detection of pesticides in tap and treated wastewater was developed and validated according to the ISO/IEC 17025:1999. Key features of this method include direct injection of 100 microL of sample, an 11 min separation by means of a rapid resolution liquid chromatography system with a 4.6 mm x 50 mm, 1.8 microm particle size reverse phase column and detection by electrospray ionization (ESI) MS-MS. The limits of detection were below 15 ng L(-1) and correlation coefficients for the calibration curves in the range of 30-2000 ng L(-1) were higher than 0.99. Precision was always below 20% and accuracy was confirmed by external evaluation. The main advantages of this method are direct injection of sample without preparative procedures and low limits of detection that fulfill the requirements established by the current European regulations governing pesticide detection.

Uranium concentration in blood samples of Southern Iraqi leukemia patients using CR-39 track detector

International Nuclear Information System (INIS)

Al-Hamzawi, A.A.; Al-Qadisiyah University, Qadisiyah; Jaafar, M.S.; Tawfiq, N.F.

2014-01-01

The simple and effective technique of fission track etch has been applied to determine trace concentration of uranium in human blood samples taken from two groups of male and female participants: leukemia patients and healthy subjects group. The blood samples of leukemia patients and healthy subjects were collected from three key southern governorates namely, Basrah, Muthanna and Dhi-Qar. These governorates were the centers of intensive military activities during the 1991 and 2003 Gulf wars, and the discarded weapons are still lying around in these regions. CR-39 track detector was used for registration of induced fission tracks. The results show that the highest recorded uranium concentration in the blood samples of leukemia patients was 4.71 ppb (female, 45 years old, from Basrah) and the minimum concentration was 1.91 ppb (male, 3 years old, from Muthanna). For healthy group, the maximum uranium concentration was 2.15 ppb (female, 55 years old, from Basrah) and the minimum concentration was 0.86 ppb (male, 5 years old, from Dhi-Qar). It has been found that the uranium concentrations in human blood samples of leukemia patients are higher than those of the healthy group. These uranium concentrations in the leukemia patients group were significantly different (P < 0.001) from those in the healthy group. (author)

Associations between injection risk and community disadvantage among suburban injection drug users in southwestern Connecticut, USA.

Science.gov (United States)

Heimer, Robert; Barbour, Russell; Palacios, Wilson R; Nichols, Lisa G; Grau, Lauretta E

2014-03-01

Increases in drug abuse, injection, and opioid overdoses in suburban communities led us to study injectors residing in suburban communities in southwestern Connecticut, US. We sought to understand the influence of residence on risk and injection-associated diseases. Injectors were recruited by respondent-driven sampling and interviewed about sociodemographics, somatic and mental health, injection risk, and interactions with healthcare, harm reduction, substance abuse treatment, and criminal justice systems. HIV, hepatitis B and C (HBV and HCV) serological testing was also conducted. Our sample was consistent in geographic distribution and age to the general population and to the patterns of heroin-associated overdose deaths in the suburban towns. High rates of interaction with drug abuse treatment and criminal justice systems contrasted with scant use of harm reduction services. The only factors associated with both dependent variables-residence in less disadvantaged census tracts and more injection risk-were younger age and injecting in one's own residence. This contrasts with the common association among urban injectors of injection-associated risk behaviors and residence in disadvantaged communities. Poor social support and moderate/severe depression were associated with risky injection practices (but not residence in specific classes of census tracts), suggesting that a region-wide dual diagnosis approach to the expansion of harm reduction services could be effective at reducing the negative consequences of injection drug use.

Rapid assessment of injection practices in Cambodia, 2002

Directory of Open Access Journals (Sweden)

Goldstein Susan

2005-06-01

Full Text Available Abstract Background Injection overuse and unsafe injection practices facilitate transmission of bloodborne pathogens such as hepatitis B virus (HBV, hepatitis C virus (HCV, and human immunodeficiency virus (HIV. Anecdotal reports of unsafe and unnecessary therapeutic injections and the high prevalence of HBV (8.0%, HCV (6.5%, and HIV (2.6% infection in Cambodia have raised concern over injection safety. To estimate the magnitude and patterns of such practices, a rapid assessment of injection practices was conducted. Methods We surveyed a random sample of the general population in Takeo Province and convenience samples of prescribers and injection providers in Takeo Province and Phnom Penh city regarding injection-related knowledge, attitudes, and practices. Injection providers were observed administering injections. Data were collected using standardized methods adapted from the World Health Organization safe injection assessment guidelines. Results Among the general population sample (n = 500, the overall injection rate was 5.9 injections per person-year, with 40% of participants reporting receipt of ≥ 1 injection during the previous 6 months. Therapeutic injections, intravenous infusions, and immunizations accounted for 74%, 16% and 10% of injections, respectively. The majority (>85% of injections were received in the private sector. All participants who recalled their last injection reported the injection was administered with a newly opened disposable syringe and needle. Prescribers (n = 60 reported that 47% of the total prescriptions they wrote included a therapeutic injection or infusion. Among injection providers (n = 60, 58% recapped the syringe after use and 13% did not dispose of the used needle and syringe appropriately. Over half (53% of the providers reported a needlestick injury during the previous 12 months. Ninety percent of prescribers and injection providers were aware HBV, HCV, and HIV were transmitted through unsafe

Chemochromic Hydrogen Leak Detectors

Science.gov (United States)

Roberson, Luke; Captain, Janine; Williams, Martha; Smith, Trent; Tate, LaNetra; Raissi, Ali; Mohajeri, Nahid; Muradov, Nazim; Bokerman, Gary

2009-01-01

At NASA, hydrogen safety is a key concern for space shuttle processing. Leaks of any level must be quickly recognized and addressed due to hydrogen s lower explosion limit. Chemo - chromic devices have been developed to detect hydrogen gas in several embodiments. Because hydrogen is odorless and colorless and poses an explosion hazard, there is an emerging need for sensors to quickly and accurately detect low levels of leaking hydrogen in fuel cells and other advanced energy- generating systems in which hydrogen is used as fuel. The device incorporates a chemo - chromic pigment into a base polymer. The article can reversibly or irreversibly change color upon exposure to hydrogen. The irreversible pigment changes color from a light beige to a dark gray. The sensitivity of the pigment can be tailored to its application by altering its exposure to gas through the incorporation of one or more additives or polymer matrix. Furthermore, through the incorporation of insulating additives, the chemochromic sensor can operate at cryogenic temperatures as low as 78 K. A chemochromic detector of this type can be manufactured into any feasible polymer part including injection molded plastic parts, fiber-spun textiles, or extruded tapes. The detectors are simple, inexpensive, portable, and do not require an external power source. The chemochromic detectors were installed and removed easily at the KSC launch pad without need for special expertise. These detectors may require an external monitor such as the human eye, camera, or electronic detector; however, they could be left in place, unmonitored, and examined later for color change to determine whether there had been exposure to hydrogen. In one type of envisioned application, chemochromic detectors would be fabricated as outer layers (e.g., casings or coatings) on high-pressure hydrogen storage tanks and other components of hydrogen-handling systems to provide visible indications of hydrogen leaks caused by fatigue failures or

Speciation of mercury in fish samples by flow injection catalytic cold vapour atomic absorption spectrometry

Energy Technology Data Exchange (ETDEWEB)

Zhang Yanlin [NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Churchill, Victoria 3842 (Australia); Adeloju, Samuel B., E-mail: Sam.Adeloju@monash.edu [NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Churchill, Victoria 3842 (Australia)

2012-04-06

Highlights: Black-Right-Pointing-Pointer Successful speciation of inorganic and organic Hg with Fe{sup 3+}, Cu{sup 2+} and thiourea as catalysts. Black-Right-Pointing-Pointer Best sensitivity enhancement and similar sensitivity for MeHg and Hg{sup 2+} with Fe{sup 3+}. Black-Right-Pointing-Pointer Successful use of Hg{sup 2+} as the primary standard for quantification of inorganic and total-Hg. Black-Right-Pointing-Pointer Quantitative extraction of Hg and MeHg with 2 M HCl which contained thiourea. Black-Right-Pointing-Pointer Integration with FIA for rapid analysis with a sample throughput of 180 h{sup -1}. - Abstract: A rapid flow injection catalytic cold vapour atomic absorption spectrometric (FI-CCV-AAS) method is described for speciation and determination of mercury in biological samples. Varying concentrations of NaBH{sub 4} were employed for mercury vapour generation from inorganic and mixture of inorganic and organic (total) Hg. The presence of Fe{sup 3+}, Cu{sup 2+} and thiourea had catalytic effect on mercury vapour generation from methylmercury (MeHg) and, when together, Cu{sup 2+} and thiourea had synergistic catalytic effect on the vapour generation. Of the two metal ions, Fe{sup 3+} gave the best sensitivity enhancement, achieving the same sensitivity for MeHg and inorganic Hg{sup 2+}. Due to similarity of resulting sensitivity, Hg{sup 2+} was used successfully as a primary standard for quantification of inorganic and total Hg. The catalysis was homogeneous in nature, and it was assumed that the breaking of the C-Hg bond was facilitated by the delocalization of the 5d electron pairs in Hg atom. The extraction of MeHg and inorganic mercury (In-Hg) in fish samples were achieved quantitatively with hydrochloric acid in the presence of thiourea and determined by FI-CCV-AAS. The application of the method to the quantification of mercury species in a fish liver reference material DOLT-4 gave 91.5% and 102.3% recoveries for total and methyl mercury

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

Neutron beam imaging with GEM detectors

International Nuclear Information System (INIS)

Albani, G.; Cazzaniga, C.; Rebai, M.; Gorini, G.; Croci, G.; Muraro, A.; Cippo, E. Perelli; Tardocchi, M.; Cavenago, M.; Murtas, F.; Claps, G.; Pasqualotto, R.

2015-01-01

Neutron GEM-based detectors represent a new frontier of devices in neutron physics applications where a very high neutron flux must be measured such as future fusion experiments (e.g. ITER Neutral beam Injector) and spallation sources (e.g. the European Spallation source). This kind of detectors can be properly adapted to be used both as beam monitors but also as neutron diffraction detectors that could represent a valid alternative for the 3 He detectors replacement. Fast neutron GEM detectors (nGEM) feature a cathode composed by one layer of polyethylene and one of aluminium (neutron scattering on hydrogen generates protons that are detected in the gas) while thermal neutron GEM detectors (bGEM) are equipped with a borated aluminium cathode (charged particles are generated through the 10 B(n,α) 7 Li reaction). GEM detectors can be realized in large area (1 m 2 ) and their readout can be pixelated. Three different prototypes of nGEM and one prototype of bGEM detectors of different areas and equipped with different types of readout have been built and tested. All the detectors have been used to measure the fast and thermal neutron 2D beam image at the ISIS-VESUVIO beamline. The different kinds of readout patterns (different areas of the pixels) have been compared in similar conditions. All the detectors measured a width of the beam profile consitent with the expected one. The imaging property of each detector was then tested by inserting samples of different material and shape in the beam. All the samples were correctly reconstructed and the definition of the reconstruction depends on the type of readout anode. The fast neutron beam profile reconstruction was then compared to the one obtained by diamond detectors positioned on the same beamline while the thermal neutron one was compared to the imaged obtained by cadmium-coupled x-rays films. Also efficiency and the gamma background rejection have been determined. These prototypes represent the first step towards

Laboratory and test beam results from a large-area silicon drift detector

CERN Document Server

Bonvicini, V; Giubellino, P; Gregorio, A; Idzik, M; Kolojvari, A A; Montaño-Zetina, L M; Nouais, D; Petta, C; Rashevsky, A; Randazzo, N; Reito, S; Tosello, F; Vacchi, A; Vinogradov, L I; Zampa, N

2000-01-01

A very large-area (6.75*8 cm/sup 2/) silicon drift detector with integrated high-voltage divider has been designed, produced and fully characterised in the laboratory by means of ad hoc designed MOS injection electrodes. The detector is of the "butterfly" type, the sensitive area being subdivided into two regions with a maximum drift length of 3.3 cm. The device was also tested in a pion beam (at the CERN PS) tagged by means of a microstrip detector telescope. Bipolar VLSI front-end cells featuring a noise of 250 e/sup -/ RMS at 0 pF with a slope of 40 e/sup -//pF have been used to read out the signals. The detector showed an excellent stability and featured the expected characteristics. Some preliminary results will be presented. (12 refs).

A novel flow injection chemiluminescence method for automated and miniaturized determination of phenols in smoked food samples.

Science.gov (United States)

Vakh, Christina; Evdokimova, Ekaterina; Pochivalov, Aleksei; Moskvin, Leonid; Bulatov, Andrey

2017-12-15

An easily performed fully automated and miniaturized flow injection chemiluminescence (CL) method for determination of phenols in smoked food samples has been proposed. This method includes the ultrasound assisted solid-liquid extraction coupled with gas-diffusion separation of phenols from smoked food sample and analytes absorption into a NaOH solution in a specially designed gas-diffusion cell. The flow system was designed to focus on automation and miniaturization with minimal sample and reagent consumption by inexpensive instrumentation. The luminol - N-bromosuccinimide system in an alkaline medium was used for the CL determination of phenols. The limit of detection of the proposed procedure was 3·10 -8 ·molL -1 (0.01mgkg -1 ) in terms of phenol. The presented method demonstrated to be a good tool for easy, rapid and cost-effective point-of-need screening phenols in smoked food samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

The scope of detector Medipix2 in micro-radiography of biological samples

Czech Academy of Sciences Publication Activity Database

Dammer, J.; Weyda, František; Jakůbek, J.; Škrabal, P.; Sopko, V.; Vavřík, D.

2011-01-01

Roč. 633, č. 1 (2011), s. 175-176 ISSN 0168-9002. [International Workshop on Radiation Imaging Detectors /11./. Praha, 29.06.2009-03.07.2009] R&D Projects: GA MŠk 2B06005 Grant - others:Ministerstvo školství(CZ) 6840770040; GA MŠk(CZ) 1P04LA211; GA MŠk(CZ) LC06041 Program:1P; LC Institutional research plan: CEZ:AV0Z50070508 Keywords : x-ray imaging * digital radiography * photon and x-ray detectors Subject RIV: EA - Cell Biology Impact factor: 1.207, year: 2011

An analysis of respondent driven sampling with Injection Drug Users (IDU) in Albania and the Russian Federation.

Science.gov (United States)

Stormer, Ame; Tun, Waimar; Guli, Lisa; Harxhi, Arjan; Bodanovskaia, Zinaida; Yakovleva, Anna; Rusakova, Maia; Levina, Olga; Bani, Roland; Rjepaj, Klodian; Bino, Silva

2006-11-01

Injection drug users in Tirana, Albania and St. Petersburg, Russia were recruited into a study assessing HIV-related behaviors and HIV serostatus using Respondent Driven Sampling (RDS), a peer-driven recruitment sampling strategy that results in a probability sample. (Salganik M, Heckathorn DD. Sampling and estimation in hidden populations using respondent-driven sampling. Sociol Method. 2004;34:193-239). This paper presents a comparison of RDS implementation, findings on network and recruitment characteristics, and lessons learned. Initiated with 13 to 15 seeds, approximately 200 IDUs were recruited within 8 weeks. Information resulting from RDS indicates that social network patterns from the two studies differ greatly. Female IDUs in Tirana had smaller network sizes than male IDUs, unlike in St. Petersburg where female IDUs had larger network sizes than male IDUs. Recruitment patterns in each country also differed by demographic categories. Recruitment analyses indicate that IDUs form socially distinct groups by sex in Tirana, whereas there was a greater degree of gender mixing patterns in St. Petersburg. RDS proved to be an effective means of surveying these hard-to-reach populations.

Multi-detector row computed tomography angiography of peripheral arterial disease

International Nuclear Information System (INIS)

Kock, Marc C.J.M.; Dijkshoorn, Marcel L.; Pattynama, Peter M.T.; Myriam Hunink, M.G.

2007-01-01

With the introduction of multi-detector row computed tomography (MDCT), scan speed and image quality has improved considerably. Since the longitudinal coverage is no longer a limitation, multi-detector row computed tomography angiography (MDCTA) is increasingly used to depict the peripheral arterial runoff. Hence, it is important to know the advantages and limitations of this new non-invasive alternative for the reference test, digital subtraction angiography. Optimization of the acquisition parameters and the contrast delivery is important to achieve a reliable enhancement of the entire arterial runoff in patients with peripheral arterial disease (PAD) using fast CT scanners. The purpose of this review is to discuss the different scanning and injection protocols using 4-, 16-, and 64-detector row CT scanners, to propose effective methods to evaluate and to present large data sets, to discuss its clinical value and major limitations, and to review the literature on the validity, reliability, and cost-effectiveness of multi-detector row CT in the evaluation of PAD. (orig.)

Applying a low energy HPGe detector gamma ray spectrometric technique for the evaluation of Pu/Am ratio in biological samples.

Science.gov (United States)

Singh, I S; Mishra, Lokpati; Yadav, J R; Nadar, M Y; Rao, D D; Pradeepkumar, K S

2015-10-01

The estimation of Pu/(241)Am ratio in the biological samples is an important input for the assessment of internal dose received by the workers. The radiochemical separation of Pu isotopes and (241)Am in a sample followed by alpha spectrometry is a widely used technique for the determination of Pu/(241)Am ratio. However, this method is time consuming and many times quick estimation is required. In this work, Pu/(241)Am ratio in the biological sample was estimated with HPGe detector based measurements using gamma/X-rays emitted by these radionuclides. These results were compared with those obtained from alpha spectroscopy of sample after radiochemical analysis and found to be in good agreement. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dual Power Supplies for PEP-II Injection Kickers

CERN Document Server

Olszewski, Joseph; Iverson, Richard; Kulikov, Artem; Pappas, Chris

2005-01-01

Originally the PEP-II injection kickers where powered by one power supply. Since the kicker magnets where not perfectly matched, the stored beam got excited by about 7% of the maximum kicker amplitude. This led to luminosity losses which were especially obvious for trickle injection when the detector is on for data taking. Therefore two independant power supplies with thyratrons in the tunnel next to the kicker magnet were installed. This also reduces the necessary power by about a factor of five since there are no long cables that have to be charged. The kickers are now independantly adjustable to eliminate any non-closure of the kicker system and therefore excitation of the stored beam. Setup, commissioning and fine tuning of this system are discussed.

Dual Power Supplies for PEP-II Injection Kickers

Energy Technology Data Exchange (ETDEWEB)

Olszewski, J; Decker, F.-J.; Iverson, R.H.; Kulikov, A.; Pappas, C.; /SLAC

2005-05-25

Originally the PEP-II injection kickers were powered by one power supply. Since the kicker magnets where not perfectly matched, the stored beam got excited by about 7% of the maximum kicker amplitude. This led to luminosity losses which were especially obvious for trickle injection when the detector is on for data taking. Therefore two independent power supplies with thyratrons in the tunnel next to the kicker magnet were installed. This also reduces the necessary power by about a factor of four since there are no long cables that have to be charged. The kickers are now independently adjustable to eliminate any non-closure of the kicker system and therefore excitation of the stored beam. Setup, commissioning and fine tuning of this system are discussed.

Dual Power Supplies for PEP-II Injection Kickers

International Nuclear Information System (INIS)

Olszewski, J; Decker, F.-J.; Iverson, R.H.; Kulikov, A.; Pappas, C.; SLAC

2005-01-01

Originally the PEP-II injection kickers were powered by one power supply. Since the kicker magnets where not perfectly matched, the stored beam got excited by about 7% of the maximum kicker amplitude. This led to luminosity losses which were especially obvious for trickle injection when the detector is on for data taking. Therefore two independent power supplies with thyratrons in the tunnel next to the kicker magnet were installed. This also reduces the necessary power by about a factor of four since there are no long cables that have to be charged. The kickers are now independently adjustable to eliminate any non-closure of the kicker system and therefore excitation of the stored beam. Setup, commissioning and fine tuning of this system are discussed

New developments on silicon drift detectors

International Nuclear Information System (INIS)

Rashevsky, A.

1996-01-01

In the frame of the project to develop large-area linear drift detectors few prototypes have been designed and produced. the function of these prototypes is to allow the evaluation of the solutions chosen for the geometry of the on-board electrodes and the production process. On these prototypes it is studied the static characteristics and measured time of-flight and charge collection injecting charges with an IR laser source. It is report the results from one of the prototypes

Super high voltage Schottky diode with low leakage current for x- and γ-ray detector application

International Nuclear Information System (INIS)

Kosyachenko, L. A.; Sklyarchuk, V. M.; Sklyarchuk, O. F.; Maslyanchuk, O. L.; Gnatyuk, V. A.; Aoki, T.

2009-01-01

A significant improvement in x-/γ-ray detector performance has been achieved by forming both rectifying and near-Ohmic contacts by the deposition of Ni on opposite surfaces of semi-insulating CdTe crystals pretreated by special chemical etching and Ar-ion bombardment with different parameters. The reduced injection of the minority carriers from the near-Ohmic contact in the neutral part of the diode provides low leakage current even at high bias ( 2 at 2000 V and 293 K). The electrical properties of the detectors are well described quantitatively by the generation-recombination Sah-Noyce-Shockley theory excepting the high reverse voltage range where some injection of minority carriers takes place

AN APPLICATION OF FLOW INJECTION ANALYSIS WITH GAS DIFFUSION AND SPECTROPHOTOMETRIC DETECTION FOR THE MONITORING OF DISSOLVED SULPHIDE CONCENTRATION IN ENVIRONMENTAL SAMPLES

Directory of Open Access Journals (Sweden)

Malwina Cykowska

2014-10-01

Full Text Available The monitoring of the concentration of sulphide is very important from the environment point of view because of high toxicity of hydrogen sulphide. What is more hydrogen sulphide is an important pollution indicator. In many cases the determination of sulphide is very difficult due to complicated matrix of some environmental samples, which causes that most analytical methods cannot be used. Flow injection analysis allows to avoid matrix problem what makes it suitable for a wide range of applications in analytical laboratories. In this paper determination of dissolved sulphide in environmental samples by gas-diffusion flow injection analysis with spectrophotometric detection was presented. Used gas-diffusion separation ensures the elimination of interferences caused by sample matrix and gives the ability of determination of sulphides in coloured and turbid samples. Studies to optimize the measurement conditions and to determine the value of the validation parameters (e.g. limit of detection, limit of quantification, precision, accuracy were carried out. Obtained results confirm the usefulness of the method for monitoring the concentration of dissolved sulphides in water and waste water. Full automation and work in a closed system greatly reduces time of analysis, minimizes consumption of sample and reagents and increases safety of analyst’s work.

Cerenkov Detectors for Fission Product Monitoring in Reactor Coolant Water

Energy Technology Data Exchange (ETDEWEB)

Strindehag, O

1967-09-15

The expected properties of Cerenkov detectors when used for fission product monitoring in water cooled reactors and test loops are discussed from the point of view of the knowledge of the sensitivity of these detectors to some beta emitting isotopes. The basic theory for calculation of the detector response is presented, taking the optical transmission in the sample container and the properties of the photomultiplier tube into account. Special attention is paid to the energy resolution of this type of Cerenkov detector. For the design of practical detectors the results from several investigations of various window and reflector materials are given, and the selection of photomultiplier tubes is briefly discussed. In the case of optical reflectors and photomultiplier tubes reference is made to two previous reports by the author. The influence of the size and geometry of the sample container on the energy resolution follows from a separate investigation, as well as the relative merits of sample containers with transparent inner walls. Provided that the energy resolution of the Cerenkov detector is sufficiently high, there are several reasons for using this detector type for failed-fuel-element detection. It seems possible to attain the desired energy resolution by careful detector design.

40 CFR 1065.270 - Chemiluminescent detector.

Science.gov (United States)

2010-07-01

... Chemiluminescent detector. (a) Application. You may use a chemiluminescent detector (CLD) to measure NOX concentration in raw or diluted exhaust for batch or continuous sampling. We generally accept a CLD for NOX...) Component requirements. We recommend that you use a CLD that meets the specifications in Table 1 of § 1065...

Flow injection analysis: Emerging tool for laboratory automation in radiochemistry

International Nuclear Information System (INIS)

Egorov, O.; Ruzicka, J.; Grate, J.W.; Janata, J.

1996-01-01

Automation of routine and serial assays is a common practice of modern analytical laboratory, while it is virtually nonexistent in the field of radiochemistry. Flow injection analysis (FIA) is a general solution handling methodology that has been extensively used for automation of routine assays in many areas of analytical chemistry. Reproducible automated solution handling and on-line separation capabilities are among several distinctive features that make FI a very promising, yet under utilized tool for automation in analytical radiochemistry. The potential of the technique is demonstrated through the development of an automated 90 Sr analyzer and its application in the analysis of tank waste samples from the Hanford site. Sequential injection (SI), the latest generation of FIA, is used to rapidly separate 90 Sr from interfering radionuclides and deliver separated Sr zone to a flow-through liquid scintillation detector. The separation is performed on a mini column containing Sr-specific sorbent extraction material, which selectively retains Sr under acidic conditions. The 90 Sr is eluted with water, mixed with scintillation cocktail, and sent through the flow cell of a flow through counter, where 90 Sr radioactivity is detected as a transient signal. Both peak area and peak height can be used for quantification of sample radioactivity. Alternatively, stopped flow detection can be performed to improve detection precision for low activity samples. The authors current research activities are focused on expansion of radiochemical applications of FIA methodology, with an ultimate goal of creating a set of automated methods that will cover the basic needs of radiochemical analysis at the Hanford site. The results of preliminary experiments indicate that FIA is a highly suitable technique for the automation of chemically more challenging separations, such as separation of actinide elements

Electromagnetic interactions in the MINOS detectors

Energy Technology Data Exchange (ETDEWEB)

Vahle, Patricia LaVern [Univ. of Texas, Austin, TX (United States)

2004-08-01

MINoS is a long-baseline neutrino experiment designed to observe the oscillation of neutrinos traveling between two detectors, a Near Detector at Fermi National Accelerator Laboratory and a Far Detector at the Soudan Underground Laboratory in northern Minnesota. Precision measurement of the oscillation parameters requires a better than 5% absolute energy calibration with is derived using a dedicated calibration detector, called CalDet. A smaller version of the MINOS detectors, the CalDet was exposed to particular beams in the CERN PS East Area test beams in 2001-2003. This document describes the conditions under which the CalDet beam data were taken, establishes selection criteria to identify a sample of electrons, and discusses the characteristics of electromagnetic interactions in the CalDet.

Results from cosmics and first LHC beam with the ALICE HMPID detector

CERN Document Server

Volpe, Giacomo

2009-01-01

The ALICE HMPID (High Momentum Particle IDentification) detector has been designed to identify charged pions and kaons in the range 1 < p < 3 GeV/c and protons in the range 1.5 < p < 5 GeV/c. It consists of seven identical proximity focusing RICH (Ring Imaging Cherenkov) counters, covering in total 11 m2, which exploit large area MWPC equipped with CsI photocathodes for Cherenkov light imaging emitted in a liquid C6F14 radiator. The ALICE detector has been widely commissioned using cosmics and LHC beam from December 2007 until October 2008. During the cosmics data taking the HMPID detector collected a large set of data, using mainly the trigger provided by the TOF detector. We present here preliminary results of detector alignment using TPC tracking. The HMPID could be operated in a stable way, at a safe HV setting, also during LHC beam injection and circulation tests, when a very large occupancy (up to 50%) was achieved. Resulting gain mapping and overall detector performance will also be discuss...

Borehole Muon Detector Development

Science.gov (United States)

Bonneville, A.; Flygare, J.; Kouzes, R.; Lintereur, A.; Yamaoka, J. A. K.; Varner, G. S.

2015-12-01

Increasing atmospheric CO2 concentrations have spurred investigation into carbon sequestration methods. One of the possibilities being considered, storing super-critical CO2 in underground reservoirs, has drawn more attention and pilot projects are being supported worldwide. Monitoring of the post-injection fate of CO2 is of utmost importance. Generally, monitoring options are active methods, such as 4D seismic reflection or pressure measurements in monitoring wells. We propose here to develop a 4-D density tomography of subsurface CO2 reservoirs using cosmic-ray muon detectors deployed in a borehole. Muon detection is a relatively mature field of particle physics and there are many muon detector designs, though most are quite large and not designed for subsurface measurements. The primary technical challenge preventing deployment of this technology in the subsurface is the lack of miniaturized muon-tracking detectors capable of fitting in standard boreholes and that will resist the harsh underground conditions. A detector with these capabilities is being developed by a collaboration supported by the U.S. Department of Energy. Current simulations based on a Monte Carlo modeling code predict that the incoming muon angle can be resolved with an error of approximately two degrees, using either underground or sea level spectra. The robustness of the design comes primarily from the use of scintillating rods as opposed to drift tubes. The rods are arrayed in alternating layers to provide a coordinate scheme. Preliminary testing and measurements are currently being performed to test and enhance the performance of the scintillating rods, in both a laboratory and a shallow underground facility. The simulation predictions and data from the experiments will be presented.

A charged aerosol detector/chemiluminescent nitrogen detector/liquid chromatography/mass spectrometry system for regular and fragment compound analysis in drug discovery.

Science.gov (United States)

Jiang, Yutao; Hascall, Daniel; Li, Delia; Pease, Joseph H

2015-09-11

In this paper, we introduce a high throughput LCMS/UV/CAD/CLND system that improves upon previously reported systems by increasing both the quantitation accuracy and the range of compounds amenable to testing, in particular, low molecular weight "fragment" compounds. This system consists of a charged aerosol detector (CAD) and chemiluminescent nitrogen detector (CLND) added to a LCMS/UV system. Our results show that the addition of CAD and CLND to LCMS/UV is more reliable for concentration determination for a wider range of compounds than either detector alone. Our setup also allows for the parallel analysis of each sample by all four detectors and so does not significantly increase run time per sample. Copyright © 2015 Elsevier B.V. All rights reserved.

Determination of gamma emitting radionuclides in environmental air and precipitation samples with a Ge(Li) detector

International Nuclear Information System (INIS)

Hoetzl, H.; Rosner, G.; Winkler, R.; Sansoni, B.

1977-01-01

The concentrations of the radionuclides 7 Be, 54 Mn, 95 Zr, 95 Nb, 103 Ru, 106 Ru, 125 Sb, 137 Cs, 140 Ba/ 140 La, 141 Ce and 144 Ce in ground level air and of 7 Be, 95 Zr, 137 Cs and 144 Ce in precipitation were determined since 1970 and 1971 respectively at Neuherberg, 10 km north of Munich, by gamma spectrometry using a 60 cm 3 Ge(Li) detector. Dust samples were collected twice a month 1 m above ground from about 40,000 m 3 of air on 46 cm x 28 cm microsorbane filters and pressed to small cylinders of 35 cm 3 in size. Sensitivity of the procedure is of the order of 1 fCi/m 3 for air and of 10 pCi/m 2 per month for precipitation samples at a counting time of 1500 min. (author)

Measurements of Charge Sharing Effects in Pixilated CZT/CdTe Detectors

DEFF Research Database (Denmark)

Kuvvetli, Irfan; Budtz-Jørgensen, Carl

2007-01-01

In this paper, charge sharing and charge loss effects in pixilated CZT/CdTe detectors are investigated by measurements. We measured charge sharing effects function of the inter-pixel gap (with same pixel pitch), the photon energy and the detector bias voltage for a large numbers of CZT and Cd......Te pixel detector samples. The results are used for the development of the large area X-ray and Gamma ray detector for the Atmosphere-Space Interactions Monitor (ASIM) planned for the ISS ESA Columbus module. Charge sharing measurements on detector samples with identical size and pixel geometry...

Dual concentric crystal low energy photon detector

Science.gov (United States)

Guilmette, R.A.

A photon detector for biological samples includes a block of NaI(T1) having a hole containing a thin walled cylinder of CsI(T1). At least three photo multiplier tubes are evenly spaced around the parameter of the block. Biological samples are placed within the hole, and emissions which are sensed by at least two of the photo multipliers from only the NaI(T1) detector are counted.

Sensitive detectors in HPLC

International Nuclear Information System (INIS)

Anon.

1992-01-01

Detection of sample components in HPLC is difficult for many reasons; the key difficulty is the mobile phase which usually has properties similar to the solute. A variety of detectors have been developed for use in HPLC based on one of the above approaches; however, the search is still continuing for an ideal or universal detector. A universal detector should have the following characteristics: (1) responds to all solutes or has predictable specificity; (2) high detectability and the same predictable response; (3) fast response; (4) wide range of linearity; (5) unaffected by changes in temperature and mobile-phase flow; (6) responds independently of the mobile phase; (7) makes no contribution to extracolumn band broadening; (8) reliable and convenient to use; (9) nondestructive to the solute; (10) provides qualitative information on the detected peak. Unfortunately, no available HPLC detector possesses all these properties. 145 refs

Quantitative portable gamma-spectroscopy sample analysis for non-standard sample geometries

International Nuclear Information System (INIS)

Ebara, S.B.

1998-01-01

Utilizing a portable spectroscopy system, a quantitative method for analysis of samples containing a mixture of fission and activation products in nonstandard geometries was developed. This method was not developed to replace other methods such as Monte Carlo or Discrete Ordinates but rather to offer an alternative rapid solution. The method can be used with various sample and shielding configurations where analysis on a laboratory based gamma-spectroscopy system is impractical. The portable gamma-spectroscopy method involves calibration of the detector and modeling of the sample and shielding to identify and quantify the radionuclides present in the sample. The method utilizes the intrinsic efficiency of the detector and the unattenuated gamma fluence rate at the detector surface per unit activity from the sample to calculate the nuclide activity and Minimum Detectable Activity (MDA). For a complex geometry, a computer code written for shielding applications (MICROSHIELD) is utilized to determine the unattenuated gamma fluence rate per unit activity at the detector surface. Lastly, the method is only applicable to nuclides which emit gamma-rays and cannot be used for pure beta or alpha emitters. In addition, if sample self absorption and shielding is significant, the attenuation will result in high MDA's for nuclides which solely emit low energy gamma-rays. The following presents the analysis technique and presents verification results using actual experimental data, rather than comparisons to other approximations such as Monte Carlo techniques, to demonstrate the accuracy of the method given a known geometry and source term. (author)

A timing detector with pulsed high-voltage power supply for mass measurements at CSRe

International Nuclear Information System (INIS)

Zhang, W.; Tu, X.L.; Wang, M.; Zhang, Y.H.; Xu, H.S.; Litvinov, Yu. A.; Blaum, K.

2014-01-01

Accuracy of nuclear mass measurements in storage rings depends critically on the accuracy with which the revolution times of stored ions can be obtained. In such experiments, micro-channel plates (MCP) are used as timing detectors. Due to large phase space of injected secondary beams, a large number of ions cannot be stored in the ring and is lost within the first few revolutions. However, these ions interact with the detector and can saturate the MCP and thus deteriorate its performance. In order to eliminate such effects, a fast, pulsed high-voltage power supply (PHVPS) has been employed which keeps the detector switched-off during the first few revolutions. The new detector setup was taken into operation at the Experimental Cooler-Storage-Ring CSRe in Lanzhou and resulted in a significant improvement of the detector amplitude and efficiency characteristics

Measurement of radon-222 concentration in environment sampled within short time using charcoal detector

International Nuclear Information System (INIS)

Yamasaki, Tadashi; Sekiyama, Shigenobu; Tokin, Mina; Nakayasu, Yumiko; Watanabe, Tamaki.

1994-01-01

The concentration of 222 Rn in air sampled within a very short period of time was measured using activated charcoal as the adsorber. The detector is the plastic canister containing mixture of the activated charcoal and the silica gel. The radon gas was adsorbed in the charcoal in the radon chamber at the temperature of 25degC. A little amount of liquid scintillation cocktail was added into the vial of liquid scintillation counter with the canister. The radon in the charcoal was extracted in the liquid scintillation cocktail. Alpha particles emitted from radon and its daughter nuclei in the cocktail were detected using the liquid scintillation counter. Present method has advantages of not only short sampling time of air but also adsorption of radon in charcoal under a constant temperature. The concentration of radon in air down to 2 Bq/m 3 could be detected. A kinetic model for adsorption of radon in the charcoal is also presented. The ratio of radon concentration in the charcoal to that in air under the equilibrium state of adsorption was estimated to be from 6.1 to 6.8 m 3 /kg at the temperature of 25degC. (author)

Development of flow injection method for indirect copper determination with amperometric detection in drinking water samples

Directory of Open Access Journals (Sweden)

Nikolić-Mandić Snežana

2012-01-01

Full Text Available A gas-diffusion flow injection method with amperometric detection for indirect copper determination on a silver electrode is developed. The flow through system is equipped with two injection valves and a gas-diffusion unit. In the first step, a signal of cyanide solution was recorded. In the following step a signal of cyanide in the presence of copper was measured. Interferences (Cd(II, Co(II, Ag(I, Ni(II, Fe(III, Hg(II and Zn(II were investigated and successfully removed. The calibration graph is linear in the range 1-90 μmol dm-3 of copper, correlation coefficient is 0.993, the regression equation is I = (0.0455±0.0015c + (0.4611±0.0671, I is relative signal decrease in μA and c is concentration in μmol dm-3. Relative standard deviation for six consecutive injections of 30 μmol dm-3 copper(II was 1.47 % and for 1 μmol dm-3 copper(II was 3.40 %. The detection limit, calculated as 3 s/m (where s is a standard deviation of nine measurement of a reagent blank and m is the slope of the calibration curve, was 0.32 μmol dm-3, which corresponds to 2.44 ng of copper(II (loop volume was 0.12 cm3. The method enables 60 analyses per hour and it was successfully applied on determination of copper in drinking water samples. [Acknowledgements. The authors acknowledge the grant from the Ministry of Education and Science of the Republic of Serbia, Project number 172051

Photoacoustic imaging to detect rat brain activation after cocaine hydrochloride injection

Science.gov (United States)

Jo, Janggun; Yang, Xinmai

2011-03-01

Photoacoustic imaging (PAI) was employed to detect small animal brain activation after the administration of cocaine hydrochloride. Sprague Dawley rats were injected with different concentrations (2.5, 3.0, and 5.0 mg per kg body) of cocaine hydrochloride in saline solution through tail veins. The brain functional response to the injection was monitored by photoacoustic tomography (PAT) system with horizontal scanning of cerebral cortex of rat brain. Photoacoustic microscopy (PAM) was also used for coronal view images. The modified PAT system used multiple ultrasonic detectors to reduce the scanning time and maintain a good signal-to-noise ratio (SNR). The measured photoacoustic signal changes confirmed that cocaine hydrochloride injection excited high blood volume in brain. This result shows PAI can be used to monitor drug abuse-induced brain activation.

Calibration curves for on-line leakage detection using radiotracer injection method

Directory of Open Access Journals (Sweden)

Ayoub Khatooni

2017-11-01

Full Text Available One of the most important requirements for industrial pipelines is the leakage detection. In this paper, detection of leak and determination of its amount using radioactive tracer injection method has been simulated by Monte Carlo MCNP code. The detector array included two NaI (Tl detectors which were located before and after the considered position, measure emitted gamma from radioactive tracer. After calibration of radiation detectors, the amount of leakage can be calculated based on the count difference of detectors. Also, the effect of material and thickness and diameter of pipe, crystal dimension, types of fluid, activity of tracer and its type (24Na, 82Br, 131I, 99mTc, 113mIn as well as have been investigated on the detectable amount of leakage. According to the results, for example, leakage more than 0.007% in volume of the inlet fluid for iron pipe with outer diameter 4 inch and thickness of 0.5 cm, Petrol as fluid inside pipe, 3 3 inch detector and 24Na with activity of 100 mCi can be detected by this presented method.

Application of digital sampling techniques to particle identification

International Nuclear Information System (INIS)

Bardelli, L.; Poggi, G.; Bini, M.; Carraresi, L.; Pasquali, G.; Taccetti, N.

2003-01-01

An application of digital sampling techniques is presented which can greatly simplify experiments involving sub-nanosecond time-mark determinations and energy measurements with nuclear detectors, used for Pulse Shape Analysis and Time of Flight measurements in heavy ion experiments. In this work a 100 M Sample/s, 12 bit analog to digital converter has been used: examples of this technique applied to Silicon and CsI(Tl) detectors in heavy-ions experiments involving particle identification via Pulse Shape analysis and Time of Flight measurements are presented. The system is suited for applications to large detector arrays and to different kinds of detectors. Some preliminary results regarding the simulation of current signals in Silicon detectors are also discussed. (authors)

The influence of technological parameters on the dynamic behavior of "liquid wood" samples obtained by injection molding

Science.gov (United States)

Plavanescu Mazurchevici, Simona; Carausu, Constantin; Comaneci, Radu; Nedelcu, Dumitru

2017-10-01

The plastic products contribute to environmental pollution. Replacing the plastic materials with biodegradable materials with superior properties is an absolute necessity and important research direction for the near future. The first steps in this regard were the creation of composite materials containing natural fibers with positive effects on the environment that have penetrated in different fields. The bioplastics and biocomposites made from natural fibers is a topical solution. The next step was made towards obtaining biodegradable and recyclable materials based on cellulose, lignin and no carcinogens. In this category fall the "liquid wood" with a use up to five times without affecting the mechanical properties. "Liquid wood" is a high quality thermoplastic biocomposite. "Liquid wood" is a biopolymer composite divided in three categories, ARBOFORM®, ARBOBLEND® and ARBOFILL®, which have differed composition in terms of lignin percentage, being delivered by Tecnaro, as granules, [1]. The paper's research was focus on Arboform L V3 Nature and Arboform L V3 Nature reinforced with aramid fiber. In the experimental plan were taken into account six parameters (Dinj - direction of injection [°]; Ttop - melting temperature [°C]; Pinj - injection pressure [MPa] Ss - speed [m/min]; tinj - injection time [s] and tc - cooling time [s]) each with two levels, research carried on by Taguchi methodology. Processing Taguchi method allowed both Taguchi setting work parameters influence on storage modulus and damping as the size and influence their ranking. Experimental research concerning the influence technological parameters on storage modulus of samples obtained by injection from Arboform L V3 Nature yielded an average of 6055MPa and descending order as follows: Trac, Ss, Pinj, Dinj and Ttop. The average of model for reinforced material was 6419MPa and descending order of parameters influence such as: Dinj, Trac, Ttop, tinj, Ss and Pinj.

Tritium depth profiling by AMS in carbon samples from fusion experiments

International Nuclear Information System (INIS)

Friedrich, M.; Pilz, W.; Sun, G.; Behrisch, R.; Garcia-Rosales, C.

2001-01-01

Tritium depth profiling measurements by accelerator mass spectrometry have been performed at a facility installed at the Rossendorf 3 MV Tandetron. In order to achieve an uniform erosion at the target surface inside of a commercial Cs ion sputtering source and to avoid edge effects, the samples were mechanically scanned inside of a commercial Cs sputter ion source. The sputtered negative ions were mass analysed by the injection magnet of the Tandetron. The tritium ions are counted after the acceleration with semiconductor detectors. Depth profiles have been measured for carbon samples which had been exposed to the plasma at the first wall of the Garching fusion experiment ASDEX-Upgrade and from the European fusion experiment JET, Culham/UK. A dedicated AMS facility with an air-insulated 100 kV tandem accelerator for depth profiling measurements at samples with high tritium concentration is under construction. First results of test operation are presented. (orig.)

Status of SAT CID InSb detector technology and applications

International Nuclear Information System (INIS)

Chatard, J.P.; Lussereau, A.; Lorans, D.

1985-01-01

This paper presents SAT indium antimonide Charge Injection Devices (C.I.D) Technology, post focal plane signal processing and some applications. These detectors are constituted by MOS capacitors realized on InSb wafers using integrated circuit-like processing. When a negative voltage is applied to the structure (put it into depletion) the capacitors form integrating detectors for use in 3-5 μm band. Linear arrays constituted by a line of single capacitors, matrix arrays constituted by a group of two coupled MOS capacitors, collect and store photon generated charge carriers. In the last case, the selection of a site is accomplished by X-Y decoding technique

Biotelemetric detection of the disappearance of subcutaneously injected /sup 125/I-NPH insulin

Energy Technology Data Exchange (ETDEWEB)

Kolendorf, K; Bojsen, J

1982-02-01

A biotelemetric method with Geiger-Mueller (GM) detectors fixed to the skin surface was used for continuous registration of the disappearance rate of subcutaneously injected /sup 125/I-NPH insulin. Methodological problems concerning counting geometry were investigated by comparing the disappearance of radioactivity, measured the GM- and NaI-detectors, respectively, and by scanning of the radioactive source. The size and position of the subcutaneous depot was unchanged throughout the study. Movement artifacts could be avoided. The coefficient of variation for distribution of ratios between count rates for GM- and NaI-detectors was 3.0% +/- 1.1 (SD) (range 0.9-4.0%) over periods of 24 h. It is concluded that the biotelemetry technique proved to be a clinically useful procedure for insulin absorption studies.

Gamma-Ray Background Variability in Mobile Detectors

Science.gov (United States)

Aucott, Timothy John

. This is accomplished by making many hours of background measurements with a truck-mounted system, which utilizes high-purity germanium detectors for spectroscopy and sodium iodide detectors for coded aperture imaging. This system also utilizes various peripheral sensors, such as panoramic cameras, laser ranging systems, global positioning systems, and a weather station to provide context for the gamma-ray data. About three hundred hours of data were taken in the San Francisco Bay Area, covering a wide variety of environments that might be encountered in operational scenarios. These measurements were used in a source injection study to evaluate the sensitivity of different algorithms (imaging and spectroscopy) and hardware (sodium iodide and high-purity germanium detectors). These measurements confirm that background distributions in large, mobile detector systems are dominated by systematic, not statistical variations, and both spectroscopy and imaging were found to substantially reduce this variability. Spectroscopy performed better than the coded aperture for the given scintillator array (one square meter of sodium iodide) for a variety of sources and geometries. By modeling the statistical and systematic uncertainties of the background, the data can be sampled to simulate the performance of a detector array of arbitrary size and resolution. With a larger array or lower resolution detectors, however imaging was better able to compensate for background variability.

Responses and mechanisms of positive electron affinity molecules in the N2 mode of the thermionic ionization detector and the electron-capture detector

International Nuclear Information System (INIS)

Jones, C.S.

1989-01-01

Very little knowledge has been acquired in the past on the mechanistic pathway by which molecules respond in the N 2 mode of the thermionic ionization detector. An attempt is made here to elucidate the response mechanism of the detector. The basic response mechanisms are known for the electron capture detector, and an attempt is made to identify the certain mechanism by which selected molecules respond. The resonance electron capture rate constant has been believed to be temperature independent, and investigations of the temperature dependence of electron capture responses are presented. Mechanisms for the N 2 mode of the thermionic ionization detector have been proposed by examining the detector response to positive electron affinity molecules and by measurement of the ions produced by the detector. Electron capture mechanisms for selected molecules have been proposed by examining their temperature dependent responses in the electron capture detector and negative ion mass spectra of the samples. In studies of the resonance electron capture rate constant, the relative responses of selected positive electron affinity molecules and their temperature dependent responses were investigated. Positive electron affinity did not guarantee large responses in the N 2 mode thermionic ionization detector. High mass ions were measured following ionization of samples in the detector. Responses in the electron capture detector varied with temperature and electron affinity

The two sides of silicon detectors

International Nuclear Information System (INIS)

Devine, S.R.

2001-10-01

Results are presented on in situ irradiation of silicon detector's at cryogenic temperature. The results show that irradiation at cryogenic temperatures does not detrimentally effect a silicon detectors performance when compared to its irradiation at room temperature. Operation of silicon devices at cryogenic temperatures offers the advantage of reducing radiation-induced leakage current to levels of a few pA, while at 130K the Lazarus Effect plays an important role i.e. minimum voltage required for full depletion. Performing voltage scans on a 'standard' silicon pad detector pre- and post annealing, the charge collection efficiency was found to be 60% at 200V and 95% at 200V respectively. Time dependence measurements are presented, showing that for a dose of 6.5x10 14 p/cm 2 (450GeV protons) the time dependence of the charge collection efficiency is negligible. However, for higher doses, 1.2x10 15 p/cm 2 , the charge collection efficiency drops from an initial measured value of 67% to a stable value of 58% over a period of 15 minutes for reversed biased diodes. An analysis of the 'double junction' effect is also presented. A comparison between the Transient Current Technique and an X-ray technique is presented. The double junction has been observed in p + /n/n + silicon detectors after irradiation beyond 'type inversion', corresponding to a fluence equivalent to ∼3x10 13 cm -2 1MeV neutrons, producing p + /p/n + and essentially two p-n junctions within one device. With increasing bias voltage, as the electric field is extending into the detector bulk from opposite sides of the silicon detector, there are two distinct depletion regions that collect charge signal independently. Summing the signal charge from the two regions, one is able to reconstruct the initial energy of the incident particle. From Transient Current measurements it is apparent that E-field manipulation is possible by excess carrier injection, enabling a high enough E-field to extend across the

Polymeric microchip for the simultaneous determination of anions and cations by hydrodynamic injection using a dual-channel sequential injection microchip electrophoresis system.

Science.gov (United States)

Gaudry, Adam J; Nai, Yi Heng; Guijt, Rosanne M; Breadmore, Michael C

2014-04-01

A dual-channel sequential injection microchip capillary electrophoresis system with pressure-driven injection is demonstrated for simultaneous separations of anions and cations from a single sample. The poly(methyl methacrylate) (PMMA) microchips feature integral in-plane contactless conductivity detection electrodes. A novel, hydrodynamic "split-injection" method utilizes background electrolyte (BGE) sheathing to gate the sample flows, while control over the injection volume is achieved by balancing hydrodynamic resistances using external hydrodynamic resistors. Injection is realized by a unique flow-through interface, allowing for automated, continuous sampling for sequential injection analysis by microchip electrophoresis. The developed system was very robust, with individual microchips used for up to 2000 analyses with lifetimes limited by irreversible blockages of the microchannels. The unique dual-channel geometry was demonstrated by the simultaneous separation of three cations and three anions in individual microchannels in under 40 s with limits of detection (LODs) ranging from 1.5 to 24 μM. From a series of 100 sequential injections the %RSDs were determined for every fifth run, resulting in %RSDs for migration times that ranged from 0.3 to 0.7 (n = 20) and 2.3 to 4.5 for peak area (n = 20). This system offers low LODs and a high degree of reproducibility and robustness while the hydrodynamic injection eliminates electrokinetic bias during injection, making it attractive for a wide range of rapid, sensitive, and quantitative online analytical applications.

A 90 element CdTe array detector

Energy Technology Data Exchange (ETDEWEB)

Iwase, Y.; Onozuka, A.; Ohmori, M. (Nippon Mining Co. Ltd., Toda, Saitama (Japan). Electronic Material and Components Labs.); Funaki, M. (Nippon Mining Co. Ltd., Toda, Saitama (Japan). Materials Development Research Labs.)

1992-11-15

The fabrication of a CdTe array radiation detector and its radiation detection characteristics are described. In order to obtain high efficiency of charge collection and realize uniform detection sensitivity, current-voltage characteristics with the combination of large and small barrier height contacts and three kinds of CdTe crystals have been investigated. It was found that the Schottky barrier height of electroless Pt deposition was 0.97 eV, which effectively suppressed electron injection. By using the crystal grown by the travelling heater method with a Cl concentration of 2 ppm, carrier lifetimes for electrons and holes of 1.0 and 0.5 [mu]s, respectively, were achieved. A 90 element array detector exhibited an energy resolution as low as 4.5 keV and a count rate variation of less than 5% for 60 keV [gamma]-rays. (orig.).

A 90 element CdTe array detector

Science.gov (United States)

Iwase, Y.; Funaki, M.; Onozuka, A.; Ohmori, M.

1992-11-01

The fabrication of a CdTe array radiation detector and its radiation detection characteristics are described. In order to obtain high efficiency of charge collection and realize uniform detection sensitivity, current-voltage characteristics with the combination of large and small barrier height contacts and three kinds of CdTe crystals have been investigated. It was found that the Schottky barrier height of electroless Pt deposition was 0.97 eV, which effectively suppressed electron injection. By using the crystal grown by the travelling heater method with a Cl concentration of 2 ppm, carrier lifetimes for electrons and holes of 1.0 and 0.5 μs, respectively, were achieved. A 90 element array detector exhibited an energy resolution as low as 4.5 keV and a count rate variation of less than 5% for 60 keV γ-rays.

Experimental investigation of supercurrent enhancement in S-N-S junctions by non-equilibrium injection into supercurrent-carrying bound Andreev states

DEFF Research Database (Denmark)

Kutchinsky, Jonatan; Taboryski, Rafael Jozef; Sørensen, C B

2001-01-01

We report measurements on three-terminal superconductor-semiconductor-superconductor injection devices demonstrating enhancement of the supercurrent by injection from a superconducting injector electrode. Two other electrodes were used to form the detector junction. Applying a small voltage...... of enhancement of the supercurrent by non-equilibrium injection into bound supercurrent-carrying Andreev states. The effect persists to temperatures where the equilibrium supercurrent has vanished. (C) 2001 Elsevier Science B.V. All rights reserved....

Magnesium borate radiothermoluminescent detectors

International Nuclear Information System (INIS)

Kazanskaya, V.A.; Kuzmin, V.V.; Minaeva, E.E.; Sokolov, A.D.

1974-01-01

In the report the technology of obtaining polycrystalline magnesium borate activated by dysprosium is described briefly and the method of preparing the tabletted detectors from it is presented. The dependence of the light sum of the samples on the proportion of the components and on the sintering regime has shown that the most sensitive material is obtained at the proportion of boric anhydride and magnesium oxide 2.2-2.4 and at the dysprosium concentration about 1 milligram-atom per gram molecule of the base. The glow curve of such a material has a simple form with one peak the maximum of which is located at 190-200 0 C. The measurement of the main dosimetric characteristics of the magnesium borate tabletted detectors and the comparison with similar parmaeters of the lithium fluoride tabletted detectors have shown that at practically identical effective number the former detectors have the following substantial advantages: the sensitivity is ten-twenty times as large, they are substantially more technological on synthesis of the radiothermoluminophor and during the production of the tabletted detectors, they have a simple glow curve, they do not require the utilization of the thermocycling during the use. (author)

Estimation of the quantification uncertainty from flow injection and liquid chromatography transient signals in inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Laborda, Francisco; Medrano, Jesus; Castillo, Juan R.

2004-01-01

The quality of the quantitative results obtained from transient signals in high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICPMS) and flow injection-inductively coupled plasma mass spectrometry (FI-ICPMS) was investigated under multielement conditions. Quantification methods were based on multiple-point calibration by simple and weighted linear regression, and double-point calibration (measurement of the baseline and one standard). An uncertainty model, which includes the main sources of uncertainty from FI-ICPMS and HPLC-ICPMS (signal measurement, sample flow rate and injection volume), was developed to estimate peak area uncertainties and statistical weights used in weighted linear regression. The behaviour of the ICPMS instrument was characterized in order to be considered in the model, concluding that the instrument works as a concentration detector when it is used to monitorize transient signals from flow injection or chromatographic separations. Proper quantification by the three calibration methods was achieved when compared to reference materials, although the double-point calibration allowed to obtain results of the same quality as the multiple-point calibration, shortening the calibration time. Relative expanded uncertainties ranged from 10-20% for concentrations around the LOQ to 5% for concentrations higher than 100 times the LOQ

Development of a scintillator detector set with counter and data acquisition for flow measurements

CERN Document Server

Costa, F E D

2002-01-01

A portable counter with data acquisition system for flow measurements was developed, using the pulse velocity technique. This consists in determining the tracer transit time mixed homogeneously to the liquid or gas pipelines. The counter comprises: (a) two CsI(Tl) crystals solid state detectors, associated with Si PIN photodiodes, with compatible sensitivity to the injected radiotracers activities; (b) amplification units; (c) analogue-to-digital interface, which processes and displays the detectors counting separately and in real time, but in a same temporal axis, via a computer screen and (d) 30-m coaxial cables for signals transmission from each detector to the processing unit. Experiments were carried out for the detector and associated electronic characterizations. The equipment showed to be suitable for flow measurements in an industrial plant, in the real situation.

Status of the HISS MUSIC detector

International Nuclear Information System (INIS)

Crawford, H.J.; Flores, F.; Bieser, F.

1984-01-01

This note describes the status of a new type of high resolution large area charged particle detector constructed for use at the Bevalac HISS facility. High charge resolution is attained by measuring many samples of the ionization produced along the path of a particle as it traverses 144 cm of P10 gas. A Multiple Sampling Ionization Chamber (MUSIC) detector was selected for use at HISS because it can cover a large area(1M x 1M) at relatively low cost and return individual charge identification for multiple fragments emitted from relativistic heavy ion interactions

Towards spin injection into silicon

Energy Technology Data Exchange (ETDEWEB)

Dash, S.P.

2007-08-15

Si has been studied for the purpose of spin injection extensively in this thesis. Three different concepts for spin injection into Si have been addressed: (1) spin injection through a ferromagnet-Si Schottky contact, (2) spin injection using MgO tunnel barriers in between the ferromagnet and Si, and (3) spin injection from Mn-doped Si (DMS) as spin aligner. (1) FM-Si Schottky contact for spin injection: To be able to improve the interface qualities one needs to understand the atomic processes involved in the formation of silicide phases. In order to obtain more detailed insight into the formation of such phases the initial stages of growth of Co and Fe were studied in situ by HRBS with monolayer depth resolution.(2) MgO tunnel barrier for spin injection into Si: The fabrication and characterization of ultra-thin crystalline MgO tunnel barriers on Si (100) was presented. (3) Mn doped Si for spin injection: Si-based diluted magnetic semiconductor samples were prepared by doping Si with Mn by two different methods i) by Mn ion implantation and ii) by in-diffusion of Mn atoms (solid state growth). (orig.)

Study of /sup 210/Pb and /sup 210/Po distributions in environmental samples by CR-39 track detector

Energy Technology Data Exchange (ETDEWEB)

Hunyadi, I.; Somogyi, G.; Szilagyi, S. (Magyar Tudomanyos Akademia, Debrecen. Atommag Kutato Intezete)

1984-01-01

Activity concentration distributions of long-lived alpha-emitters in aerosol samples are analysed by high-resolution autoradiography in CR-39. A study of the alpha-activity attached to aerosols of different particulate sizes separated by a cascade impactor is also performed. It is found that, in the majority of samples, the alpha-activity can be dominantly related to the presence of /sup 210/Po produced by its beta-active precursor /sup 210/Pb. In our studies we have applied the following methods: 1) analysis of alpha-decay properties by means of autoradiographs taken at different post-sampling times, 2) spectroscopical study of individual alpha-tracks and track clusters by a method developed by us for high-resolution alpha-energy determination. In the second method the parameters to be measured are the major axis of surface track opening, the diameter of etched out track end, the total length measurable on the surface along the projected track, and the thickness of layer etched away from the detector surface.

Using Network Sampling and Recruitment Data to Understand Social Structures Related to Community Health in a Population of People Who Inject Drugs in Rural Puerto Rico.

Science.gov (United States)

Coronado-García, Mayra; Thrash, Courtney R; Welch-Lazoritz, Melissa; Gauthier, Robin; Reyes, Juan Carlos; Khan, Bilal; Dombrowski, Kirk

2017-06-01

This research examined the social network and recruitment patterns of a sample of people who inject drugs (PWIDs) in rural Puerto Rico, in an attempt to uncover systematic clustering and between-group social boundaries that potentially influence disease spread. Respondent driven sampling was utilized to obtain a sample of PWID in rural Puerto Rico. Through eight initial "seeds", 317 injection drug users were recruited. Using recruitment patterns of this sample, estimates of homophily and affiliation were calculated using RDSAT. Analyses showed clustering within the social network of PWID in rural Puerto Rico. In particular, females showed a very high tendency to recruit male PWID, which suggests low social cohesion among female PWID. Results for (believed) HCV status at the time of interview indicate that HCV+ individuals were less likely to interact with HCV- individuals or those who were unaware of their status, and may be acting as "gatekeepers" to prevent disease spread. Individuals who participated in a substance use program were more likely to affiliate with one another. The use of speedballs was related to clustering within the network, in which individuals who injected this mixture were more likely to affiliate with other speedball users. Social clustering based on several characteristics and behaviors were found within the IDU population in rural Puerto Rico. RDS was effective in not only garnering a sample of PWID in rural Puerto Rico, but also in uncovering social clustering that can potentially influence disease spread among this population.

High variability of HIV and HCV seroprevalence and risk behaviours among people who inject drugs: results from a cross-sectional study using respondent-driven sampling in eight German cities (2011-14).

Science.gov (United States)

Wenz, Benjamin; Nielsen, Stine; Gassowski, Martyna; Santos-Hövener, Claudia; Cai, Wei; Ross, R Stefan; Bock, Claus-Thomas; Ratsch, Boris-Alexander; Kücherer, Claudia; Bannert, Norbert; Bremer, Viviane; Hamouda, Osamah; Marcus, Ulrich; Zimmermann, Ruth

2016-09-05

People who inject drugs (PWID) are at increased risk of acquiring and transmitting HIV and Hepatitis C (HCV) due to sharing injection paraphernalia and unprotected sex. To generate seroprevalence data on HIV and HCV among PWID and related data on risk behaviour, a multicentre sero- and behavioural survey using respondent driven sampling (RDS) was conducted in eight German cities between 2011 and 2014. We also evaluated the feasibility and effectiveness of RDS for recruiting PWID in the study cities. Eligible for participation were people who had injected drugs within the last 12 months, were 16 years or older, and who consumed in one of the study cities. Participants were recruited, using low-threshold drop-in facilities as study sites. Initial seeds were selected to represent various sub-groups of people who inject drugs (PWID). Participants completed a face-to-face interview with a structured questionnaire about socio-demographics, sexual and injecting risk behaviours, as well as the utilisation of health services. Capillary blood samples were collected as dried blood spots and were anonymously tested for serological and molecular markers of HIV and HCV. The results are shown as range of proportions (min. and max. values (%)) in the respective study cities. For evaluation of the sampling method we applied criteria from the STROBE guidelines. Overall, 2,077 PWID were recruited. The range of age medians was 29-41 years, 18.5-35.3 % of participants were female, and 9.2-30.6 % were foreign born. Median time span since first injection were 10-18 years. Injecting during the last 30 days was reported by 76.0-88.4 % of participants. Sharing needle/syringes (last 30 days) ranged between 4.7 and 22.3 %, while sharing unsterile paraphernalia (spoon, filter, water, last 30 days) was reported by 33.0-43.8 %. A majority of participants (72.8-85.8 %) reported incarceration at least once, and 17.8-39.8 % had injected while incarcerated. Between 30.8 and 66.2 % were

Diverse HIV epidemics among people who inject drugs in Thailand: Evidence from respondent-driven sampling surveys in Bangkok and Chiang Mai☆

Science.gov (United States)

Prybylski, Dimitri; Manopaiboon, Chomnad; Visavakum, Prin; Yongvanitjit, Kovit; Aramrattana, Apinun; Manomaipiboon, Parnrudee; Tanpradech, Suvimon; Suksripanich, Orapin; Pattanasin, Sarika; Wolfe, Mitchell; Whitehead, Sara J.

2016-01-01

Background Thailand’s long-standing HIV sero-sentinel surveillance system for people who inject drugs (PWID) is confined to those in methadone-based drug treatment clinics and representative data are scarce, especially outside of Bangkok. Methods We conducted probability-based respondent-driven sampling (RDS) surveys in Bangkok (n = 738) and Chiang Mai (n = 309) to increase understanding of local HIV epidemics and to better inform the planning of evidence-based interventions. Results PWID had different epidemiological profiles in these two cities. Overall HIV prevalence was higher in Bangkok (23.6% vs. 10.9%, p Chiang Mai, HIV infections appear to be more recently acquired and PWID were younger and had higher levels of recent injecting and sexual risk behaviors with lower levels of intervention exposure. Methamphetamine was the predominant drug injected in both sites and polydrug use was common although levels and patterns of the specific drugs injected varied significantly between the sites. In multivariate analysis, recent midazolam injection was significantly associated with HIV infection in Chiang Mai (adjusted odds ratio = 8.1; 95% confidence interval: 1.2–54.5) whereas in Bangkok HIV status was not associated with recent risk behaviors as infections had likely been acquired in the past. Conclusion PWID epidemics in Thailand are heterogeneous and driven by local factors. There is a need to customize intervention strategies for PWID in different settings and to integrate population-based survey methods such as RDS into routine surveillance to monitor the national response. PMID:25640153

Diverse HIV epidemics among people who inject drugs in Thailand: evidence from respondent-driven sampling surveys in Bangkok and Chiang Mai.

Science.gov (United States)

Prybylski, Dimitri; Manopaiboon, Chomnad; Visavakum, Prin; Yongvanitjit, Kovit; Aramrattana, Apinun; Manomaipiboon, Parnrudee; Tanpradech, Suvimon; Suksripanich, Orapin; Pattanasin, Sarika; Wolfe, Mitchell; Whitehead, Sara J

2015-03-01

Thailand's long-standing HIV sero-sentinel surveillance system for people who inject drugs (PWID) is confined to those in methadone-based drug treatment clinics and representative data are scarce, especially outside of Bangkok. We conducted probability-based respondent-driven sampling (RDS) surveys in Bangkok (n=738) and Chiang Mai (n=309) to increase understanding of local HIV epidemics and to better inform the planning of evidence-based interventions. PWID had different epidemiological profiles in these two cities. Overall HIV prevalence was higher in Bangkok (23.6% vs. 10.9%, pChiang Mai, HIV infections appear to be more recently acquired and PWID were younger and had higher levels of recent injecting and sexual risk behaviors with lower levels of intervention exposure. Methamphetamine was the predominant drug injected in both sites and polydrug use was common although levels and patterns of the specific drugs injected varied significantly between the sites. In multivariate analysis, recent midazolam injection was significantly associated with HIV infection in Chiang Mai (adjusted odds ratio=8.1; 95% confidence interval: 1.2-54.5) whereas in Bangkok HIV status was not associated with recent risk behaviors as infections had likely been acquired in the past. PWID epidemics in Thailand are heterogeneous and driven by local factors. There is a need to customize intervention strategies for PWID in different settings and to integrate population-based survey methods such as RDS into routine surveillance to monitor the national response. Published by Elsevier Ireland Ltd.

A neutron activation detector

International Nuclear Information System (INIS)

Ambardanishvili, T.S.; Kolomiitsev, M.A.; Zakharina, T.Y.; Dundua, V.J.; Chikhladze, N.V.

1973-01-01

The present invention concerns a neutron activation detector made from a moulded and hardened composition. According to the invention, that composition contains an activable substance constituted by at least two chemical elements and/or compounds of at least two chemical elements. Each of these chemical elements is capable of reacting with the neutrons forming radio-active isotopes with vatious levels of energy during desintegration. This neutron detector is mainly suitable for measuring integral thermal neutron and fast neutron fluxes during irradiation of the sample, and also for measuring the intensities of neutron fields [fr

Small Pixel Hybrid CMOS X-ray Detectors

Science.gov (United States)

Hull, Samuel; Bray, Evan; Burrows, David N.; Chattopadhyay, Tanmoy; Falcone, Abraham; Kern, Matthew; McQuaide, Maria; Wages, Mitchell

2018-01-01

Concepts for future space-based X-ray observatories call for a large effective area and high angular resolution instrument to enable precision X-ray astronomy at high redshift and low luminosity. Hybrid CMOS detectors are well suited for such high throughput instruments, and the Penn State X-ray detector lab, in collaboration with Teledyne Imaging Sensors, has recently developed new small pixel hybrid CMOS X-ray detectors. These prototype 128x128 pixel devices have 12.5 micron pixel pitch, 200 micron fully depleted depth, and include crosstalk eliminating CTIA amplifiers and in-pixel correlated double sampling (CDS) capability. We report on characteristics of these new detectors, including the best read noise ever measured for an X-ray hybrid CMOS detector, 5.67 e- (RMS).

Study of axial injection of polarized protons into the grenoble cyclotron

International Nuclear Information System (INIS)

Pabot, J.

1969-01-01

By injecting ions axially into a cyclotron, it is possible to accelerate particles (polarized particles, heavy ions, etc...) obtainable only with difficulty when an internal ion source is used. In this work, after justifying the choice of an axial injection device equipped with a 'pseudo-cylindrical' deflector for the Grenoble cyclotron, we study theoretically the principle of such a detector, the choice of its parameters, and the effect of this choice on the conditions of acceleration of the beam by the cyclotron. From the experimental point of view, this report describes two operations which made it possible to check that the chosen injection device operated satisfactorily, qualitatively initially (electron model), then quantitatively (proton model). In conclusion, we believe that the Grenoble cyclotron thus equipped will be able to provide a relatively dense beam of polarized protons. (author) [fr

An ultra-thin Schottky diode as a transmission particle detector for biological microbeams

International Nuclear Information System (INIS)

Grad, M; Harken, A; Randers-Pehrson, G; Brenner, D J; Attinger, D

2012-01-01

We fabricated ultrathin metal-semiconductor Schottky diodes for use as transmission particle detectors in the biological microbeam at Columbia University's Radiological Research Accelerator Facility (RARAF). The RARAF microbeam can deliver a precise dose of ionizing radiation in cell nuclei with sub-micron precision. To ensure an accurate delivery of charged particles, the facility currently uses a commercial charged-particle detector placed after the sample. We present here a transmission detector that will be placed between the particle accelerator and the biological specimen, allowing the irradiation of samples that would otherwise block radiation from reaching a detector behind the sample. Four detectors were fabricated with co-planar gold and aluminum electrodes thermally evaporated onto etched n-type crystalline silicon substrates, with device thicknesses ranging from 8.5 μm - 13.5 μm. We show coincident detections and pulse-height distributions of charged particles in both the transmission detector and the commercial detector above it. Detections are demonstrated at a range of operating conditions, including incoming particle type, count rate, and beam location on the detectors. The 13.5 μm detector is shown to work best to detect 2.7 MeV protons (H + ), and the 8.5 μm detector is shown to work best to detect 5.4 MeV alpha particles ( 4 He ++ ). The development of a transmission detector enables a range of new experiments to take place at RARAF on radiation-stopping samples such as thick tissues, targets that need immersion microscopy, and integrated microfluidic devices for handling larger quantities of cells and small organisms.

An ultra-thin Schottky diode as a transmission particle detector for biological microbeams

Science.gov (United States)

Harken, Andrew; Randers-Pehrson, Gerhard; Attinger, Daniel; Brenner, David J.

2013-01-01

We fabricated ultrathin metal-semiconductor Schottky diodes for use as transmission particle detectors in the biological microbeam at Columbia University’s Radiological Research Accelerator Facility (RARAF). The RARAF microbeam can deliver a precise dose of ionizing radiation in cell nuclei with sub-micron precision. To ensure an accurate delivery of charged particles, the facility currently uses a commercial charged-particle detector placed after the sample. We present here a transmission detector that will be placed between the particle accelerator and the biological specimen, allowing the irradiation of samples that would otherwise block radiation from reaching a detector behind the sample. Four detectors were fabricated with co-planar gold and aluminum electrodes thermally evaporated onto etched n-type crystalline silicon substrates, with device thicknesses ranging from 8.5 μm – 13.5 μm. We show coincident detections and pulse-height distributions of charged particles in both the transmission detector and the commercial detector above it. Detections are demonstrated at a range of operating conditions, including incoming particle type, count rate, and beam location on the detectors. The 13.5 μm detector is shown to work best to detect 2.7 MeV protons (H+), and the 8.5 μm detector is shown to work best to detect 5.4 MeV alpha particles (4He++). The development of a transmission detector enables a range of new experiments to take place at RARAF on radiation-stopping samples such as thick tissues, targets that need immersion microscopy, and integrated microfluidic devices for handling larger quantities of cells and small organisms. PMID:24058378

Detector simulation needs for detector designers

International Nuclear Information System (INIS)

Hanson, G.G.

1987-11-01

Computer simulation of the components of SSC detectors and of the complete detectors will be very important for the designs of the detectors. The ratio of events from interesting physics to events from background processes is very low, so detailed understanding of detector response to the backgrounds is needed. Any large detector for the SSC will be very complex and expensive and every effort must be made to design detectors which will have excellent performance and will not have to undergo major rebuilding. Some areas in which computer simulation is particularly needed are pattern recognition in tracking detectors and development of shower simulation code which can be trusted as an aid in the design and optimization of calorimeters, including their electron identification performance. Existing codes require too much computer time to be practical and need to be compared with test beam data at energies of several hundred GeV. Computer simulation of the processing of the data, including electronics response to the signals from the detector components, processing of the data by microprocessors on the detector, the trigger, and data acquisition will be required. In this report we discuss the detector simulation needs for detector designers

A projective geometry lead fiber scintillator detector

International Nuclear Information System (INIS)

Paar, H.; Thomas, D.; Sivertz, M.; Ong, B.; Acosta, D.; Taylor, T.; Shreiner, B.

1990-01-01

The Superconducting Super Collider (SSC), presently under construction near Dallas, Texas requires highly sophisticated particle detectors. The energy and particle flux at the SSC are more than an order of magnitude higher than the highest machine located at the Fermi National Accelerator near Chicago. An important element of particle detectors for the SSC is the calorimeter. It measures a particle's energy by sampling its energy deposit in heavy material, such as (depleted) uranium or lead. The sampling medium must be interspersed with heavy absorber material. In the case of scintillating plastic, two methods are under consideration: plates and fibers. In the case of plates, a sandwich of scintillator plates and uranium plates is constructed. In the use of fibers (still in the prototype stage), 1 mm. diameter cylindrical scintillating fibers are inserted into grooves that are machined into lead layers. The layers are stacked and epoxied together to form the required geometrical shape of the detector. Lead and scintillating plastic sampling can meet the physics requirements of the detector. This has been shown in an R ampersand D program which is underway at the University of California at San Diego (UCSD), High Energy Physics Group. This R ampersand D is funded by the Department of Energy, High Energy Physics and SSC Divisions

Use of semiconductor detector c-Si microstrip type in obtaining the digital radiographic imaging of phantoms and biological samples of mammary glands

International Nuclear Information System (INIS)

Leyva, A.; Cabal, A.; Pinera, I.; Abreu, Y.; Cruz, C. M.; Montano, L. M.; Diaz, C. C.; Fontaine, M.; Ortiz, C. M.; Padilla, F.; De la Mora, R.

2009-01-01

The present work synthesizes the experimental results obtained in the characterization of 64 micro strips crystalline silicon detector designed for experiments in high energies physics, with the objective of studying its possible application in advanced medical radiography, specifically in digital mammography and angiography. The research includes the acquisition of two-dimensional radiography of a mammography phantom using the scanning method, and its comparison with similar images simulated mathematically for different X rays sources. The paper also shows the experimental radiography of two biological samples taken from biopsies of mammas, where it is possible to identify the presence of possible pathological lesions. The results reached in this work point positively toward the effective possibility of satisfactorily introducing those advanced detectors in medical digital imaging applications. (Author)

Tranport of p-aminohippuric acid (3H-PAH), inulin and dextran out of the cranial cavity: A methodological study using intraventricular injection and sample combustion

International Nuclear Information System (INIS)

Jakobson, Aa. M.

1987-01-01

Material injected into the cerebral ventricles can leave the cerebrospinal fluid (CSF) but remain in the cranial cavity. To analyze the disappearance of 3 H- and of 14 C-labelled material from the cranial cavity, such material was injected into the lateral ventricles together with a bulk flow marker, labelled with the other radionuclide. In the present pilot study 3 H-PAH and 14 C-inulin were used. Five μl of a mixture was injected into each lateral cerebral ventricles in rats, which were killed at various intervals. The whole skull was analyzed without opening the CSF space after homogenization in the deep-frozen state. The samples were combusted and analyzed by liquid scintillation counting. Probenecid, injected intraperitoneally, inhibited the removal of 3 H-PAH from the skull cavity, as anticipated. Immediately after the intraventricular injection, however, 3 H-PAH was transiently retained, probably by uptake into actively transporting tissue. After injection of probenecid, this delay in removal was reduced. The difference in disappearance rate between 3 H-PAH and 14 C-inulin was estimated by comparing the 3 H/ 14 C ratio in the skulls with that in the injected solution, which appeared to be a better method than comparing the recovery of each compound. (author)

Depth sensitivity of Lexan polycarbonate detector

CERN Document Server

Awad, E M

1999-01-01

The dependence of the registration sensitivity of Lexan polycarbonate with depth inside the detector was studied. Samples of Lexan from General Electric were irradiated to two long range ions. These were Ni and Au ions with a projectile energy of 0.3 and 1 GeV/n. Two independent techniques, the track-diameter technique (TDT) and the track profile technique (TPT), were used. The registration sensitivity was measured at depths of 7, 10, 15, 18, 20, 28, 35 and 40 mu m inside the detector. The results of the two techniques show that the detector sensitivity decreases gradually with the depth inside the detector. It reaches 20 % less compared to sensitivity at the surface after 40 mu m have been removed.

Fine-scale spatial response of CdZnTe radiation detectors

International Nuclear Information System (INIS)

Brunett, B.A.; Van Scyoc, J.M.; Hilton, N.R.; Lund, J.C.; James, R.B.; Schlesinger, T.E.

1998-01-01

Several studies have suggested that the uniformity of Cadmium Zinc Telluride (CZT) detectors play an important role in their performance when operated as gamma-ray spectrometers. However the detailed gamma response of simple planar detectors as a function of position over the device area is largely unknown. To address this issue the authors have built a system capable of measuring the detector response with a resolution of ∼250 (micro)m. The system consists of a highly collimated (∼200 (micro)m) photon source (<150 kev) scanned over the detector using a computer controlled two-axis translation stage. Fifteen samples configured as planar detectors were examined with the new apparatus. The material grade of the detectors examined varied from counter to select discriminator. Two classes of spatial response variation were observed and are presented here. Infrared (IR) transmission images were also acquired for each sample and correlation between features in the pulse height spectrum and crystalline defects were observed

The Effect of Temperature and Injection Rate during Water Flooding Using Carbonate Core Samples: An Experimental Approach

Directory of Open Access Journals (Sweden)

Yaser Ahmadi

2016-10-01

Full Text Available In many reservoirs, after water flooding, a large volume of oil is still left behind. Hot water injection is the most basic type of thermal recovery which increase recovery by improved sweep efficiency and thermal expansion of crude.In the present work, the effects of injection rate and the temperature of the injected water were surveyed by using core flooding apparatus. Water flooding was performed at different rates (0.2, 0.3, and 0.4 cc/min and temperatures (20 and 90 °C, and the reservoir temperature was about 63 °C. Oil recovery during hot water injection was more than water injection. Moreover, it was concluded that at injection rates of 0.2, 0.3, and 0.4 cc/min breakthrough time in hot water injection occurred 10 min later in comparison to water injection. The results showed that higher oil recovery and longer breakthrough time were obtained as a result of reducing injection rate. In the first 50 minutes, the oil recovery at injection rates of 0.2, 0.3 and 0.4 cc/min was 27.5, 34, and 46% respectively. It was found that at the beginning of injection, thermal and non-thermal injection recovery factors are approximately equal. Moreover, according to the results, recovery factor at the lowest rate in hot water (T=90 °C and q=0.2 cc/min is the best condition to obtain the highest recovery.

An arc detector for neutron crystal structure investigations

Energy Technology Data Exchange (ETDEWEB)

Habib, N [Reactor and Neutron Physics Dept., Nuclear Research Center. AEA, Cairo (Egypt)

1997-12-31

An arc detector for neutron structure investigations of powder crystals using time-of-flight technique is described. In order to enable the measurement of integral intensity from about 1/4 of the Debye-Scherrer ring and for simplicity reasons, the scattering angle 20-90 degree was chosen and a special arc collimator was built. The arc collimator-detector had a divergency of about 20 minutes of arc, and the distance between detector-sample was 64 cm. Four {sup 3} He detectors were fixed on the arc of the collimator. Both efficiency and space sensitivity of the detector were determined using a point neutron source. Results of measurements show that parameters of the arc detector are acceptable for high resolution crystal structure investigations. 6 figs.

Heat flux to the limiter during disruptions and neutral beam injection in Doublet-III

International Nuclear Information System (INIS)

Hino, T.; DeGrassie, J.; Taylor, T.S.; Hopkins, G.; Meyer, C.; Petrie, T.W.; Kahn, C.L.; Ejima, S.

1984-01-01

The heat flux to the Doublet-III primary limiter has been monitored during plasma disruptions and during neutral beam injection. The surface temperature of the movable TiC-coated graphite limiter was measured with an Inframetrics thermal imaging system and a suitably filtered silicon photodiode spot detector. In addition, the floating electric potential of the limiter with respect to the vacuum vessel was measured. The heat pulse duration to the limiter was measured by the spot detector with a time response of x approx.= 10 μs and these times were correlated with the plasma parameters. In limiter discharges, 20% of the plasma kinetic stored energy goes to the limiter during disruptions. The power balance during disruptions is also discussed. During neutral beam injection, the limiter is not heated uniformly; the ion drift side receives much more thermal flux than the electron drift side. The fraction of beam power going to the limiter is as high as approx.= 35% in normal limiter discharges. (orig.)

A multisyringe flow injection method for the determination of thorium in water samples using spectrophotometric detection

International Nuclear Information System (INIS)

Guzman-Mar, J.L.; Aracely Hernandez-Ramirez; Lopez-Chuken, U.J.; Lopez-de-Alba, P.L.; Victor Cerda

2011-01-01

A fast and simple multisyringe flow injection analysis (MSFIA) method for routine determination of thorium in water samples was developed. The methodology was based on the complexation reaction of thorium with arsenazo (III) at pH 2.0. Thorium concentrations were spectrophotometrically detected at 665 nm. Under optimal conditions, Beer's law was obeyed over the range from 0.2 to 4.5 μg mL -1 thorium, a 3σ detection limit of 0.05 μg mL -1 , and a 10σ quantification limit of 0.2 μg mL -1 were obtained. The relative standard deviations (RSD, %) at 0.5, 2.5 and 4.5 μg mL -1 was 2.8, 1.5 and 0.8%, respectively (n = 10). It was found that most of the common metal ions and anions did not interfere with the thorium determination. The proposed method was successfully applied to its analysis in various water samples. (author)

CASA-MIA: A ''precision'' EAS detector

International Nuclear Information System (INIS)

Borione, A.; Cronin, J.W.; Covault, C.E.; Fick, B.E.; Gibbs, K.G.; Krimm, H.A.; McKay, T.A.; Mueller, D.; Newport, B.J.; Ong, R.A.; Rosenberg, L.J.; Catanese, M.; Green, K.D.; Matthews, J.; Nitz, D.F.; Sinclair, D.; van der Velde, J.C.; Kieda, D.

1993-01-01

The CASA-MIA detector was constructed to search for sources of UHE neutral radiation. As such it has established limits well below those of previously reported observations and of most contemporaneous detectors. In addition to its primary mission, however, CASA-MIA measures the lateral distribution of both electrons and muons in EAS throughout a range of energies and with a degree of sampling not previously available

Aerogel for FARICH detector

Energy Technology Data Exchange (ETDEWEB)

Barnyakov, A.Yu. [Budker Institute of Nuclear Physics, Lavrentieva 11, Novosibirsk 630090 (Russian Federation); Barnyakov, M.Yu. [Budker Institute of Nuclear Physics, Lavrentieva 11, Novosibirsk 630090 (Russian Federation); Novosibirsk State Technical University, Karl Marks 20, Novosibirsk 630073 (Russian Federation); Bobrovnikov, V.S.; Buzykaev, A.R.; Gulevich, V.V. [Budker Institute of Nuclear Physics, Lavrentieva 11, Novosibirsk 630090 (Russian Federation); Danilyuk, A.F. [Boreskov Institute of Catalysis, Lavrentieva 5, Novosibirsk 630090 (Russian Federation); Kononov, S.A.; Kravchenko, E.A. [Budker Institute of Nuclear Physics, Lavrentieva 11, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Pirogova 2, Novosibirsk 630090 (Russian Federation); Kuyanov, I.A. [Budker Institute of Nuclear Physics, Lavrentieva 11, Novosibirsk 630090 (Russian Federation); Lopatin, S.A. [Boreskov Institute of Catalysis, Lavrentieva 5, Novosibirsk 630090 (Russian Federation); Onuchin, A.P.; Ovtin, I.V.; Podgornov, N.A. [Budker Institute of Nuclear Physics, Lavrentieva 11, Novosibirsk 630090 (Russian Federation); Novosibirsk State Technical University, Karl Marks 20, Novosibirsk 630073 (Russian Federation); Porosev, V.V. [Budker Institute of Nuclear Physics, Lavrentieva 11, Novosibirsk 630090 (Russian Federation); Predein, A.Yu.; Protsenko, R.S. [Boreskov Institute of Catalysis, Lavrentieva 5, Novosibirsk 630090 (Russian Federation)

2014-12-01

We present our current experience in preparation of focusing aerogels for the Focusing Aerogel RICH detector. Multilayer focusing aerogel tiles have been produced in Novosibirsk by a collaboration of the Budker Institute of Nuclear Physics and Boreskov Institute of Catalysis since 2004. We have obtained 2–3–4-layer blocks with the thickness of 30–45 mm. In 2012, the first samples of focusing blocks with continuous density (refractive index) gradient along thickness were produced. This technology can significantly reduce the contribution from the geometric factor of the radiator thickness to the resolution of the measured Cherenkov angle in the FARICH detector. The special installation was used for automatic control of reagents ratio during the synthesis process. The first samples were tested using the digital radiography method and on the electron beam with the FARICH prototype.

The digital flat-panel X-Ray detectors

International Nuclear Information System (INIS)

Risticj, S. Goran

2013-01-01

In a digital imaging system, the incident x-ray image must be sampled both in the spatial and intensity dimensions. In the spatial dimensions, samples are obtained as averages of the intensity over picture elements or pixels. In the intensity dimension, the signal is digitalized into one of a finite number of levels or bits. Two main types of digital flat-panel detectors are based on the direct conversion, which contains the photoconductor, and on indirect conversion, which contains phosphor. The basics of these detectors are given. Coupling traditional x-ray detection material such as photoconductors and phosphors with a large-area active-matrix readout structure forms the basis of flat panel x-ray images. Active matrix technology provides a new, highly efficient, real time method for electronically storing and measuring the product of the x-ray interaction stage whether the product is visible wavelength photons or electrical charges. The direct and indirect detectors, made as the active-matrix flat-panel detectors containing sensing/storage elements, switching elements (diodes or thin film transistors (TFTS)) and image processing module, are described. Strengths and limitations of stimulable phosphors are discussed. The main advantages and disadvantages of mentioned x-ray detectors are also analyzed. (Author)

Study of α-particle injection effect on superconductors YBa2Cu3O7-δ type

International Nuclear Information System (INIS)

Santos, G.R.

1998-01-01

Various techniques exist to qualify and quantify this radiation damage effect. The methods are based on destructive methods such as TEM, SEM, CREEP and others. This work is intended to be a starting point to the application of nondestructive techniques to study radiation damage in superconductors in nuclear application, and a creation of a nuclear data bank for different type of materials. The first scheduled nondestructive technique to be applied is positron annihilation, more specifically positron lifetime measurements. This work is based on the implementation of a technique, widely used to simulate neutron radiation effects on materials. This simulation is obtained by the injection of charged particles (ions), from an accelerator, and a beam line equipped with some special experimental arrangement to get a homogeneous distribution of injected particles in the sample. After the ion injection, or neutron damage simulation, the nuclear data are collected by different experimental setups: conventional gamma spectrometer for activation analysis, X-ray diffraction for phase change analysis, and zero detector for magnetic permeability measurements. The behavior of the magnetic permeability with temperature of YBa 2 Cu 3 O 7-δ superconducting ceramics was studied as a function of the amount of He -2 implanted into the sample. With fluence varying from 1.2 to 6.0 x 10 6 He -2 cm -2 , the results show that the superconducting temperature T c (onset) stays nearly constant up to 2.5 x 10 6 He -2 cm -2 , decreasing afterwards for higher fluencies. An almost linear decrease is observed for T(offset). The magnetic permeability curves show structures whose shapes and relative positions to T c (onset) change with the fluence. Although this might indicate a mixture of phases coexisting inside the sample, X-ray diffraction shows no clear evidence for such a pattern. A large percentage of the damage recovers after annealing the He-implanted sample at 673 K

Mechanical Weakening during Fluid Injection in Critically Stressed Sandstones with Acoustic Monitoring

Science.gov (United States)

David, C.; Dautriat, J. D.; Sarout, J.; Macault, R.; Bertauld, D.

2014-12-01

Water weakening is a well-known phenomenon which can lead to subsidence during the production of hydrocarbon reservoirs. The example of the Ekofisk oil field in the North Sea has been well documented for years. In order to assess water weakening effects in reservoir rocks, previous studies have focused on changes in the failure envelopes derived from mechanical tests conducted on rocks saturated either with water or with inert fluids. However, little attention has been paid so far on the mechanical behaviour during the fluid injection stage, like in enhanced oil recovery operations. We studied the effect of fluid injection on the mechanical behaviour of Sherwood sandstone, a weakly-consolidated sandstone sampled at Ladram Bay in UK. In order to highlight possible weakening effects, water and inert oil have been injected into critically-loaded samples to assess their effect on strength and elastic properties and to derive the acoustic signature of the saturation front for each fluid. The specimens were instrumented with 16 ultrasonic P-wave transducers for both passive and active acoustic monitoring during fluid injection and loading. After conducting standard triaxial tests on three samples saturated with air, water and oil respectively, mechanical creep tests were conducted on dry samples loaded at 80% of the compressive strength of the dry rock. While these conditions are kept constant, a fluid is injected at the bottom end of the sample with a low back pressure (0.5 MPa) to minimize effective stress variations during injection. Both water and oil were used as the injected pore fluid in two experiments. As soon as the fluids start to flow into the samples, creep is taking place with a much higher strain rate for water injection compared to oil injection. A transition from secondary creep to tertiary creep is observed in the water injection test whereas in the oil injection test no significant creep acceleration is observed after one pore volume of oil was

Factors associated with time between using a drug and injection initiation among people who inject drugs in Kermanshah, Iran.

Science.gov (United States)

Noroozi, Mehdi; Farhadi, Mohammad Hassan; Armoon, Bahram; Farhoudian, Ali; Shushtari, Zahra Jorjoran; Sharhani, Asaad; Karimi, Salah Eddin; Sayadnasiri, Mohammad; Rezaei, Omid; Ghiasvand, Hesam

2018-05-17

Background The transition from non-injection to injection drug use dramatically increases the risk of transmitting HIV and other blood borne infections including hepatitis B virus (HBV) and hepatitis C virus (HCV). The aim of this study was to explore factors associated with the transition from first illicit drug use to first injection among drug users. Methods Using snowball sampling and convenience sampling through needle and syringe programmes (NSPs), we recruited 500 people who inject drugs (PWID) in Kermanshah, between September and December 2014. Trained interviewers collected data on socio-demographic characteristics, HIV testing and drug-related risk behaviors over the last month prior to interview using a structured questionnaire. Our main outcome variable was first illicit drug use to first injection (TIJ). TIJ was calculated by subtracting age at first drug injection from age of first illicit drug use. Results Overall, the average age at first drug use and injection were 21.4 [standard deviation (SD 5.6)] and 22.8 (SD 8.9), respectively. The average duration of injection was 6.0 (SD 4.6) years. Overall, the mean of TIJ for participants was 1.4 (IQR = 2, 4) years. Age of first injecting drug use negatively correlated with TIJ (R2 = 0.219, p = 0.001). Education level and socioeconomic status (SES), and negatively correlated with TIJ. Conclusion Some demographic factors and drug use characteristics including educational level, SES, knowledge of HIV status, age of initiating drug use, being a poly drug user and using methamphetamine were predictors of the time to transition.

[Matrix effect and application of field-amplified sample injection in the analysis of four tetracyclines in waters by capillary electrohoresis].

Science.gov (United States)

2014-08-01

The system abilities of two chromatographic techniques, capillary electrophoresis (CE) and high performance liquid chromatography (HPLC), were compared for the analysis of four tetracyclines (tetracycline, chlorotetracycline, oxytetracycline and doxycycline). The pH, concentration of background electrolyte (BGE) were optimized for the analysis of the standard mixture sample, meanwhile, the effects of separation voltage and water matrix (pH value and hardness) effects were investigated. In hydrodynamic injection (HDI) mode, a good quantitative linearity and baseline separation within 9. 0 min were obtained for the four tetracyclines at the optimal conditions; the analytical time was about half of that of HPLC. The limits of detection (LODs) were in the range of 0. 28 - 0. 62 mg/L, and the relative standard deviations (RSDs) (n= 6) of migration time and peak area were 0. 42% - 0. 56% and 2. 24% - 2. 95%, respectively. The obtained recoveries spiked in tap water and fishpond water were at the ranges of 96. 3% - 107. 2% and 87. 1% - 105. 2%, respectively. In addition, the stacking method, field-amplified sample injection (FASI), was employed to improve the sensitivity, and the LOD was down to the range of 17.8-35.5 μg/L. With FASI stacking, the RSDs (n=6) of migration time and peak area were 0. 85%-0. 95% and 1. 69%-3.43%, respectively. Due to the advantages of simple sample pretreatment and fast speed, CE is promising in the analysis of the antibiotics in environmental water.

2 π gaseous flux proportional detector

International Nuclear Information System (INIS)

Guevara, E.A.; Costello, E.D.; Di Carlo, R.O.

1986-01-01

A counting system has been developed in order to measure carbon-14 samples obtained in the course of a study of a plasmapheresis treatment for diabetic children. The system is based on the use of a 2π gaseous flux proportional detector especially designed for the stated purpose. The detector is described and experiment results are given, determining the characteristic parameters which set up the working conditions. (Author) [es

Effects of sample injection amount and time-of-flight mass spectrometric detection dynamic range on metabolome analysis by high-performance chemical isotope labeling LC-MS.

Science.gov (United States)

Zhou, Ruokun; Li, Liang

2015-04-06

The effect of sample injection amount on metabolome analysis in a chemical isotope labeling (CIL) liquid chromatography-mass spectrometry (LC-MS) platform was investigated. The performance of time-of-flight (TOF) mass spectrometers with and without a high-dynamic-range (HD) detection system was compared in the analysis of (12)C2/(13)C2-dansyl labeled human urine samples. An average of 1635 ± 21 (n = 3) peak pairs or putative metabolites was detected using the HD-TOF-MS, compared to 1429 ± 37 peak pairs from a conventional or non-HD TOF-MS. In both instruments, signal saturation was observed. However, in the HD-TOF-MS, signal saturation was mainly caused by the ionization process, while in the non-HD TOF-MS, it was caused by the detection process. To extend the MS detection range in the non-HD TOF-MS, an automated switching from using (12)C to (13)C-natural abundance peaks for peak ratio calculation when the (12)C peaks are saturated has been implemented in IsoMS, a software tool for processing CIL LC-MS data. This work illustrates that injecting an optimal sample amount is important to maximize the metabolome coverage while avoiding the sample carryover problem often associated with over-injection. A TOF mass spectrometer with an enhanced detection dynamic range can also significantly increase the number of peak pairs detected. In chemical isotope labeling (CIL) LC-MS, relative metabolite quantification is done by measuring the peak ratio of a (13)C2-/(12)C2-labeled peak pair for a given metabolite present in two comparative samples. The dynamic range of peak ratio measurement does not need to be very large, as only subtle changes of metabolite concentrations are encountered in most metabolomic studies where relative metabolome quantification of different groups of samples is performed. However, the absolute concentrations of different metabolites can be very different, requiring a technique to provide a wide detection dynamic range to allow the detection of as

Neutron μstiX. Micrometer structure investigation with real space and reciprocal space crossover using neutron imaging detectors

Energy Technology Data Exchange (ETDEWEB)

Muehlbauer, Martin Johann

2013-07-19

This work is concerned with the investigation of inhomogeneities in materials with length scales of the order of micrometers by means of neutrons. In real space this is done by neutron imaging methods measuring the transmitted signal while for Ultra Small Angle Neutron Scattering (USANS) the signal of the scattered neutrons is assigned to a spatial frequency distribution in reciprocal space. The part about neutron imaging is focused on time-resolved neutron radiography on an injection nozzle similar to the ones used for modern diesel truck engines. The associated experiments have been carried out at the neutron imaging facility ANTARES at the Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II) of the Technische Universitaet Muenchen in Garching near Munich. Especially the demands on the detector system were high. Therefore different detection methods and detector configurations have been tested. On the one hand the detector should allow for a time resolution high enough to record the injection process lasting about 900 μs. On the other hand it needed to offer a spatial resolution sufficient to resolve the test oil inside the spray hole of a maximum diameter of less than 200 μm. An advanced aim of this work is the visualization of cavitation phenomena which may occur during the injection process inside of the spray hole. In order to operate the injector at conditions as close to reality as possible a high pressure pump supplying the injector with test oil at a pressure of 1600 bar was needed in addition to the specially developed control electronics, the recuperation tank and the exhaust gas equipment for the escaping atomized spray. A second part of the work describes USANS experiments based on the idea of Dr. Roland Gaehler and carried out at the instrument D11 at the Institut Laue-Langevin in Grenoble. For this purpose a specific multi-beam geometry was applied, where a multi-slit aperture replaced the standard source aperture and the sample aperture was

Neutron μstiX. Micrometer structure investigation with real space and reciprocal space crossover using neutron imaging detectors

International Nuclear Information System (INIS)

Muehlbauer, Martin Johann

2013-01-01

This work is concerned with the investigation of inhomogeneities in materials with length scales of the order of micrometers by means of neutrons. In real space this is done by neutron imaging methods measuring the transmitted signal while for Ultra Small Angle Neutron Scattering (USANS) the signal of the scattered neutrons is assigned to a spatial frequency distribution in reciprocal space. The part about neutron imaging is focused on time-resolved neutron radiography on an injection nozzle similar to the ones used for modern diesel truck engines. The associated experiments have been carried out at the neutron imaging facility ANTARES at the Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II) of the Technische Universitaet Muenchen in Garching near Munich. Especially the demands on the detector system were high. Therefore different detection methods and detector configurations have been tested. On the one hand the detector should allow for a time resolution high enough to record the injection process lasting about 900 μs. On the other hand it needed to offer a spatial resolution sufficient to resolve the test oil inside the spray hole of a maximum diameter of less than 200 μm. An advanced aim of this work is the visualization of cavitation phenomena which may occur during the injection process inside of the spray hole. In order to operate the injector at conditions as close to reality as possible a high pressure pump supplying the injector with test oil at a pressure of 1600 bar was needed in addition to the specially developed control electronics, the recuperation tank and the exhaust gas equipment for the escaping atomized spray. A second part of the work describes USANS experiments based on the idea of Dr. Roland Gaehler and carried out at the instrument D11 at the Institut Laue-Langevin in Grenoble. For this purpose a specific multi-beam geometry was applied, where a multi-slit aperture replaced the standard source aperture and the sample aperture was

Rapid colorimetric assay for gentamicin injection.

Science.gov (United States)

Tarbutton, P

1987-01-01

A rapid colorimetric method for determining gentamicin concentration in commercial preparations of gentamicin sulfate injection was developed. Methods currently available for measuring gentamicin concentration via its colored complex with cupric ions in alkaline solution were modified to reduce the time required for a single analysis. The alkaline copper tartrate (ACT) reagent solution was prepared such that each milliliter contained 100 mumol cupric sulfate, 210 mumol potassium sodium tartrate, and 1.25 mmol sodium hydroxide. The assay involves mixing 0.3 mL gentamicin sulfate injection 40 mg/mL (of gentamicin), 1.0 mL ACT reagent, and 0.7 mL water; the absorbance of the resulting solution at 560 nm was used to calculate the gentamicin concentration in the sample. For injections containing 10 mg/mL of gentamicin, the amount of the injection was increased to 0.5 mL and water decreased to 0.5 mL. The concentration of gentamicin in samples representing 11 lots of gentamicin sulfate injection 40 mg/mL and 8 lots of gentamicin sulfate injection 10 mg/mL was determined. The specificity, reproducibility, and accuracy of the assay were assessed. The colored complex was stable for at least two hours. Gentamicin concentration ranged from 93.7 to 108% and from 95 to 109% of the stated label value of the 40 mg/mL and the 10 mg/mL injections, respectively. No components of the preservative system present in the injections interfered with the assay. Since other aminoglycosides produced a colored complex, the assay is not specific for gentamicin. The assay was accurate and reproducible over the range of 4-20 mg of gentamicin. This rapid and accurate assay can be easily applied in the hospital pharmacy setting.

First neutron spectroscopy measurements with a pixelated diamond detector at JET

Energy Technology Data Exchange (ETDEWEB)

Muraro, A., E-mail: muraro@ifp.cnr.it; Giacomelli, L.; Grosso, G.; Tardocchi, M. [Istituto di Fisica del Plasma “P. Caldirola,” CNR, Milano (Italy); Nocente, M.; Rebai, M.; Rigamonti, D.; Gorini, G. [Istituto di Fisica del Plasma “P. Caldirola,” CNR, Milano (Italy); University of Milano Bicocca, Piazza della Scienza 3, 20126 Milano (Italy); Belli, F. [Centro Ricerca ENEA-Frascati, Via E.Fermi 45, Frascati, Rome (Italy); Calvani, P.; Girolami, M.; Trucchi, D. M. [CNR—Istituto di Struttura della Materia (ISM), Via Salaria km 29.300, 00015 Monterotondo Scalo, Rome (Italy); Figueiredo, J. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisbon (Portugal); EUROfusion Programme Management Unit, Culham Science Centre, Abingdon (United Kingdom); Murari, A. [Culham Centre for Fusion Energy, Culham (United Kingdom); Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Padova (Italy); Popovichev, S. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisbon (Portugal); Collaboration: EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

2016-11-15

A prototype Single crystal Diamond Detector (SDD) was installed at the Joint European Torus (JET) in 2013 along an oblique line of sight and demonstrated the possibility to carry out neutron spectroscopy measurements with good energy resolution and detector stability in discharges heated by neutral beam injection and radio-frequency waves. Starting from these positive results, within the Vertical Neutron Spectrometer project of the Joint European Torus, we have developed a pixelated instrument consisting of a matrix of 12 independent SDDs, called the Diamond Vertical Neutron Spectrometer (DVNS), which boosts the detection efficiency of a single SDD by an order of magnitude. In this paper we describe the main features of the DVNS, including the detector design, energy resolution, and data acquisition system for on-line processing. Preliminary spectroscopy measurements of 2.5 MeV neutrons from the present deuterium plasma at JET are finally presented.

Application of solid state nuclear track detectors in radiation protection

International Nuclear Information System (INIS)

Ramachandran, T.V.; Subba Ramu, M.C.; Mishra, U.C.

1989-01-01

This article reviews the current status of the application of nuclear track detectors with emphasis on recent developments in the field of radiation protection. Track etch detectors have been used for the measurements of low level radiation in the environment, fast neutron and radon daughter inhalation dose. Recent developments in the field of dosimetry seem to be promising. In fast neutron dosimetry, track etch detectors can be used without inclusion of fissile materials by using the electrochemical etching technique. These detectors can provide important information in the energy range upto 250 keV. Survey of this range of energy with TLD is difficult because they are extremely energy dependent and over-respond to low energy neutrons. Measurement of radon using track detectors can help to lower the cost of the radon dosimeters. Certain detectors are sensitive to alpha particles from radon and their progeny. Higher sensitivity permits their use in a passive type of personnel dosimeter, which does not require the troublesome aspects of air sampling for the collection of radon daughter samples. (author), 38 refs., 8 tabs., 12 figs

Echo 2: a study of electron beams injected into the high-latitude ionosphere from a large sounding rocket

International Nuclear Information System (INIS)

Winckler, J.R.; Arnoldy, R.L.; Hendrickson, R.A.

1975-01-01

The Black Brant V-C Echo 2 rocket was launched at Fort Churchill on September 25, 1972, and it injected 64-ms pulses of electron beams of 80-mA current and 45-keV voltage into the ionosphere. This paper studies the responses of on-board electrostatic deflection and solid state detectors to injected electrons after motion in the near ionosphere and atmosphere. It is shown that it was only through some form of scattering that the detectors could sense the injected beam electrons. By means of 'phase maps' of injection and detection pitch angles a number of distinct regions are found corresponding to a rocket scattering halo, an atmospheric scattering halo, a region of weak responses, and a source of strong scattering above the rocket. The atmospheric scattering has been compared with the theoretical and experimental results of the Echo 1 experiment, and it is found to be in reasonable agreement. The rocket halo is discussed qualitatively; but no explanation is found for the backscatter from above the rocket, which may be associated with an occasional violent beam instability. This analysis has been carried out to better understand the complexities of electron motion observed near large rockets carrying artifical electron accelerators as a guide in the planning of future experiments

Atomic resolution holography using advanced reconstruction techniques for two-dimensional detectors

Energy Technology Data Exchange (ETDEWEB)

Marko, M; Szakal, A; Cser, L [Neutron Spectroscopy Department, Research Institute for Solid State Physics and Optics, PO Box 49, H-1525 Budapest (Hungary); Krexner, G [Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna (Austria); Schefer, J, E-mail: marko@szfki.h [Laboratory for Neutron Scattering (LNS), Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland)

2010-06-15

Atomic resolution holography is based on two concepts. Either the emitter of the radiation used is embedded in the sample (internal source concept) or, on account of the optical reciprocity law, the detector forms part of the sample (internal detector concept). In many cases, holographic objects (atoms and nuclei) simultaneously adopt the roles of both source and detector. Thus, the recorded image contains a mixture of both inside source and inside detector holograms. When reconstructing one type of hologram, the presence of the other hologram causes serious distortions. In the present work, we propose a new method, the so-called double reconstruction (DR), which not only suppresses the mutual distortions but also exploits the information content of the measured hologram more effectively. This novel approach also decreases the level of distortion arising from diffraction and statistical noise. The efficiency of the DR technique is significantly enhanced by employing two-dimensional (2D) area detectors. The power of the method is illustrated here by applying it to a real measurement on a palladium-hydrogen sample.

Current applications of semiconductor x-ray detectors in chemical analysis

International Nuclear Information System (INIS)

Whitehead, N.E.

1975-07-01

In the last few years, semiconductor detectors have been used as X-ray detectors with great success, and the routine rapid accumulation of X-ray spectra is now possible. This review surveys the historical development of the detectors, the utilisation, and relative merits of various means of exciting the X-radiation from the elements in the sample, and compares the technique with other methods claiming to offer the capability of simultaneous multi-element analysis. It is concluded that it is of average sensitivity, but offers some advantages from its non-destructive nature, and in some cases its ability to offer information about the spatial distribution of elements in a sample. Other types of analysis may also be possible simultaneously. Sample preparation techniques are reviewed, especially techniques of manufacturing thin samples. An appendix contains details of the very wide variety of samples which have been analysed. More than 350 references are included. (auth.)

Dual cloud point extraction coupled with hydrodynamic-electrokinetic two-step injection followed by micellar electrokinetic chromatography for simultaneous determination of trace phenolic estrogens in water samples.

Science.gov (United States)

Wen, Yingying; Li, Jinhua; Liu, Junshen; Lu, Wenhui; Ma, Jiping; Chen, Lingxin

2013-07-01

A dual cloud point extraction (dCPE) off-line enrichment procedure coupled with a hydrodynamic-electrokinetic two-step injection online enrichment technique was successfully developed for simultaneous preconcentration of trace phenolic estrogens (hexestrol, dienestrol, and diethylstilbestrol) in water samples followed by micellar electrokinetic chromatography (MEKC) analysis. Several parameters affecting the extraction and online injection conditions were optimized. Under optimal dCPE-two-step injection-MEKC conditions, detection limits of 7.9-8.9 ng/mL and good linearity in the range from 0.05 to 5 μg/mL with correlation coefficients R(2) ≥ 0.9990 were achieved. Satisfactory recoveries ranging from 83 to 108% were obtained with lake and tap water spiked at 0.1 and 0.5 μg/mL, respectively, with relative standard deviations (n = 6) of 1.3-3.1%. This method was demonstrated to be convenient, rapid, cost-effective, and environmentally benign, and could be used as an alternative to existing methods for analyzing trace residues of phenolic estrogens in water samples.

Field-Amplified Sample Injection-Micellar Electrokinetic Chromatography for the Determination of Benzophenones in Food Simulants

Directory of Open Access Journals (Sweden)

Cristina Félez

2015-07-01

Full Text Available A field-amplified sample injection-micellar electrokinetic chromatography (FASI-MEKC method for the determination of 14 benzophenones (BPs in a food simulant used in migration studies of food packaging materials was developed, allowing almost baseline separation in less than 21 min. The use of a 10 mM sodium dodecyl sulfate (SDS solution as sample matrix was mandatory to achieve FASI enhancement of the analyzed BPs. A 21- to 784-fold sensitivity enhancement was achieved with FASI-MEKC, obtaining limits of detection down to 5.1–68.4 µg/L, with acceptable run-to-run precisions (RSD values lower than 22.3% and accuracy (relative errors lower than 21.0%. Method performance was evaluated by quantifying BPs in the food simulant spiked at 500 µg/L (bellow the established specific migration limit for BP (600 µg/L by EU legislation. For a 95% confidence level, no statistical differences were observed between found and spiked concentrations (probability at the confidence level, p value, of 0.55, showing that the proposed FASI-MEKC method is suitable for the analysis of BPs in food packaging migration studies at the levels established by EU legislation.

Flow Injection and Atomic Absorption Spectrometry (FI-AAS) -

DEFF Research Database (Denmark)

Hansen, Elo Harald

1996-01-01

One of the advantages of the flow injection (FI) concept is that it is compatible with virtually all detection techniques. Being a versatile vehicle for enhancing the performance of the individual detection devices, the most spectacular results have possibly been obtained in conjunction with atomic...... the point of sample injection/introduction to the point of detection. Hence, in FI-fAAS this feature allows not only to obtain improved repeatability but also improved accuracy, and because the wash to sample ratio is high it permits the handling of samples with elevated salt contents - which...

Development of the fast, simple and fully validated high performance liquid chromatographic method with diode array detector for quantification of testosterone esters in an oil-based injectable dosage form.

Science.gov (United States)

Kozlik, Petr; Tircova, Barbora

2016-11-01

Counterfeit steroids are available on the black market, ultimately to consumers who believe they are buying a legitimate pharmaceutical item from the labeled company. In many cases, counterfeit steroids can contain lower doses or some products can be overdosed. This can unwittingly expose users to a significant health risks. The mixture of testosterone propionate, phenylpropionate, isocaproate and decanoate in an oil-based injectable dosage form belongs to the one of the most misused illicit drugs by a variety of athletes. This study developed a new, fast, simple and reliable HPLC method combined with a simple sample preparation step to determine testosterone propionate, phenylpropionate, isocaproate and decanoate in an oil-based injectable dosage form without the use of sophisticated and expensive instrumentation. The developed analytical procedure provides high throughput of samples where LC analysis takes only 6min and sample preparation of oil matrix in one step takes approximately 10min with precision ranging from 1.03 to 3.38% (RSD), and accuracy (relative error %) within ±2.01%. This method was found to be precise, linear, accurate, sensitive, selective and robust for routine application in screening of commercial pharmaceutical products based on content of mentioned testosterone esters in their oil-based injectable dosage form for counterfeit drugs. This method was successfully applied to the analysis of nine samples of commercial testosterone mixtures purchased from various sources and will be further used as an effective screening method for determination of previously mentioned testosterone esters in samples confiscated by Institute of Forensic Science (Slovakia) during the illegal trade. Copyright © 2016 Elsevier Inc. All rights reserved.

Flow injection on-line oxidizing fluorometry coupled to dialysis sampling for the study of carbamazepine-protein binding

Energy Technology Data Exchange (ETDEWEB)

Zhang Zhiqi [School of Chemistry and Materials Science, Shaanxi Normal University, Xi' an 710062 (China)]. E-mail: zqzhang@snnu.edu.cn; Liang Guoxi [School of Chemistry and Materials Science, Shaanxi Normal University, Xi' an 710062 (China)

2005-04-22

The mechanism of binding of carbamazepine (CBZ) with bovine serum albumin (BSA) has been investigated in vitro based on a new flow injection fluorometry coupled to the technique of dialysis sampling. The CBZ and BSA were mixed in different molar ratios in 0.050 mol L{sup -1} phosphate buffer (containing 0.9% NaCl), pH 7.4, and incubated at 37 {+-} 0.5 deg. C in a water bath. The dialysis sampler was utilized to sample free CBZ from mixed solution with a relative dialytic efficiency of 7.6%. Then the CBZ in dialysis solution was injected into carrier and on-line oxidized by lead dioxide solid-phase reactor into fluorescent product with a maximum excitation wavelength of 355 nm and a maximum emission wavelength of 478 nm. The fluorescence intensity measured was linear proportional with the concentration of free CBZ in mixed solution over the range of 1 x 10{sup -5} to 2 x 10{sup -4} mol L{sup -1} with the detection limit of 6 x 10{sup -6} mol L{sup -1}. According to the fluorescence measurement results from mixed solution, the association constant (K) estimated for CBZ-BSA binding and the number of the binding site (n) with Scatchard analysis were 1.08 x 10{sup 4} L mol{sup -1} and 0.94, respectively. Stern-Volmer plots indicated the presence of dynamic component in the quenching mechanism. The acting force was suggested to be mainly hydrophobic and the distance between the acceptor and donor was 3.12 nm. The estimated binding parameters agreed well with literature values.

Sample preparation

International Nuclear Information System (INIS)

Anon.

1992-01-01

Sample preparation prior to HPLC analysis is certainly one of the most important steps to consider in trace or ultratrace analysis. For many years scientists have tried to simplify the sample preparation process. It is rarely possible to inject a neat liquid sample or a sample where preparation may not be any more complex than dissolution of the sample in a given solvent. The last process alone can remove insoluble materials, which is especially helpful with the samples in complex matrices if other interactions do not affect extraction. Here, it is very likely a large number of components will not dissolve and are, therefore, eliminated by a simple filtration process. In most cases, the process of sample preparation is not as simple as dissolution of the component interest. At times, enrichment is necessary, that is, the component of interest is present in very large volume or mass of material. It needs to be concentrated in some manner so a small volume of the concentrated or enriched sample can be injected into HPLC. 88 refs

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

The silicon shower maximum detector for the STIC

International Nuclear Information System (INIS)

Alvsvaag, S.J.; Maeland, O.A.; Klovning, A.

1995-01-01

The structure of a shashlik calorimeter allows the insertion of tracking detectors within the longitudinal sampling to improve the accuracy in the determination of the direction of the showering particle and the e/π separation ability. The new forward calorimeter of the DELPHI detector has been equipped with two planes of silicon pad detectors respectively after 4 and 7.4 radiation lengths. The novelty of these silicon detectors is that to cope with the shashlik readout fibers, they had to incorporate 1.4 mm holes every cm 2 . The detector consists of circular strips with a radial pitch of 1.7 mm and an angular granularity of 22.5 , read out by means of the MX4 preamplifier. The preamplifier is located at 35 cm from the silicon detector and the signal is carried by Kapton cables bonded to the detector. The matching to the MX4 input pitch of 44 μm was made by a specially developed fanin hybrid. (orig.)

Ion detectors for isotopic measurements

Energy Technology Data Exchange (ETDEWEB)

McCormick, A.

1978-12-15

Detector development over the past two decades has been such that this is now the least likely part of the mass spectrometry equipment to give rise to the sort of measurement errors to cause concern. It is now possible to choose from a number of different types of device which can provide more or less 100% efficiency in ion beam detection under all conceivable experimental conditions required for isotopic analysis, from measurement of large samples using the traditional Faraday cage to measurement of exceedingly small ion currents by ion counting techniques. There are even methods of distinguishing one type of ionic species from another in the detector, thus improving the accuracy when unwanted isobaric species might otherwise grossly distort the measurement. Notable contributions to detector development for nuclear measurements have been made by Dietz at the Knolls Atomic Power Laboratory, by Barnett at Oak Ridge and by Daly at Atomic Weapons Research Establishment (AWRE), Aldermaston. This paper describes the detection methods which are currently in use at AWRE for isotopic analysis of solid samples for routine applications as well as non-routine applications. Other methods are merely mentioned as a stimulus for discussion.

Reverse radiometric flow injection analysis (RFIA) of radioactive waste-waters with an ASIA (Ismatec) analyzer

Energy Technology Data Exchange (ETDEWEB)

Myint, U; Win, N; San, K; Han, B; Myoe, K M [Yangon Univ. (Myanmar). Dept. of Chemistry; Toelgyessy, J [Slovak Technical Univ., Bratislava (Slovakia). Dept. of Environmental Science

1994-07-01

A new application of reverse radiometric flow injection analysis is described. RFIA was used for the analysis of radioactive wastewaters. ASIA (Ismatec) analyzer with NaI(Tl) scintillation detector was used in the study of analysis of [sup 131]I containing waste-aster. (author) 4 refs.; 3 figs.

PROTON RADIOGRAPHY WITH THE PIXEL DETECTOR TIMEPIX

Directory of Open Access Journals (Sweden)

Václav Olšanský

2016-12-01

Full Text Available This article presents the processing of radiographic data acquired using the position-sensitive hybrid semiconductor pixel detector Timepix. Measurements were made on thin samples at the medical ion-synchrotron HIT [1] in Heidelberg (Germany with a 221 MeV proton beam. The charge is energy by the particles crossing the sample is registered for generation of image contrast. Experimental data from the detector were processed for derivation of the energy loss of each proton using calibration matrices. The interaction point of the protons on the detector were determined with subpixel resolution by model fitting of the individual signals in the pixelated matrix. Three methods were used for calculation of these coordinates: Hough transformation, 2D Gaussian fitting and estimate the 2D mean. Parameters of calculation accuracy and calculation time are compared for each method. The final image was created by method with best parameters.

High variability of HIV and HCV seroprevalence and risk behaviours among people who inject drugs: results from a cross-sectional study using respondent-driven sampling in eight German cities (2011–14

Directory of Open Access Journals (Sweden)

Benjamin Wenz

2016-09-01

Full Text Available Abstract Background People who inject drugs (PWID are at increased risk of acquiring and transmitting HIV and Hepatitis C (HCV due to sharing injection paraphernalia and unprotected sex. To generate seroprevalence data on HIV and HCV among PWID and related data on risk behaviour, a multicentre sero- and behavioural survey using respondent driven sampling (RDS was conducted in eight German cities between 2011 and 2014. We also evaluated the feasibility and effectiveness of RDS for recruiting PWID in the study cities. Methods Eligible for participation were people who had injected drugs within the last 12 months, were 16 years or older, and who consumed in one of the study cities. Participants were recruited, using low-threshold drop-in facilities as study sites. Initial seeds were selected to represent various sub-groups of people who inject drugs (PWID. Participants completed a face-to-face interview with a structured questionnaire about socio-demographics, sexual and injecting risk behaviours, as well as the utilisation of health services. Capillary blood samples were collected as dried blood spots and were anonymously tested for serological and molecular markers of HIV and HCV. The results are shown as range of proportions (min. and max. values (% in the respective study cities. For evaluation of the sampling method we applied criteria from the STROBE guidelines. Results Overall, 2,077 PWID were recruited. The range of age medians was 29–41 years, 18.5–35.3 % of participants were female, and 9.2–30.6 % were foreign born. Median time span since first injection were 10–18 years. Injecting during the last 30 days was reported by 76.0–88.4 % of participants. Sharing needle/syringes (last 30 days ranged between 4.7 and 22.3 %, while sharing unsterile paraphernalia (spoon, filter, water, last 30 days was reported by 33.0–43.8 %. A majority of participants (72.8–85.8 % reported incarceration at least once, and 17.8–39.8�

Flow injection determination of lead and cadmium in hair samples from workers exposed to welding fumes

International Nuclear Information System (INIS)

Cespon-Romero, R.M.; Yebra-Biurrun, M.C.

2007-01-01

A flow injection procedure involving continuous acid leaching for lead and cadmium determination in hair samples of persons in permanent contact with a polluted workplace environment by flame atomic absorption spectrometry is proposed. Variables such as sonication time, nature and concentration of the acid solution used as leaching solution, leaching temperature, flow-rate of the continuous manifold, leaching solution volume and hair particle size were simultaneously studied by applying a Plackett-Burman design approach. Results showed that nitric acid concentration (leaching solution), leaching temperature and sonication time were statistically significant variables (confidence interval of 95%). These last two variables were finally optimised by using a central composite design. The proposed procedure allowed the determination of cadmium and lead with limits of detection 0.1 and 1.0 μg g -1 , respectively. The accuracy of the developed procedure was evaluated by the analysis of a certified reference material (CRM 397, human hair, from the BCR). The proposed method was applied with satisfactory results to the determination of Cd and Pb in human hair samples of workers exposed to welding fumes

Automatic gamma radiation scanning device and feed mechanism for plural sample holders

International Nuclear Information System (INIS)

Byrd, W.J.

1976-01-01

Apparatus is disclosed for measuring the level of gamma radiation contained in a plurality of biological samples which are located on the fibrous sheet member carried by a sample holder. The apparatus is adapted to count the radiation level of the number of closely spaced samples located in rows and columns on the sheet by automatically sequencing through the individual samples within the rows and to advance the holder to bring successive rows into proximity with the detector. The detector is moved from sample to sample within the rows, although a number of detectors can be employed. A plurality of sample holders are automatically advanced to the detector. 25 claims, 5 drawing figures

Passive sampling and analyses of common dissolved fixed gases in groundwater

International Nuclear Information System (INIS)

Spalding, Brian Patrick; Watson, David B.

2008-01-01

An in situ passive sampler and gas chromatographic protocol for analysis of the major and several minor fixed gases in groundwater was developed. A gas-tight syringe, mated to a short length of silicone tubing, was equilibrated with dissolved gases in groundwater by immersing in monitoring wells and was used to transport and to inject a 0.5 mL gas sample into a gas chromatograph. Using Ar carrier gas, a HaySep DB porous polymer phase, and sequential thermal conductivity and reductive gas detectors allowed good sensitivity for He, Ne, H2, N2, O2, CO, CH4, CO2, and N2O. Within 4 days of immersion in groundwater, samplers initially filled with either He or air attained the same and constant gas composition at an Oak Ridge, Tennessee, site heavily impacted by uranium, acidity, and nitrate. Between June 2006 and July 2007, 12 permanent groundwater wells were used to test the passive samplers in groundwater contaminated by a group of four closed radioactive wastewater seepage ponds; over a thousand passive gas samples from these wells averaged 56% CO2, 32.4% N2, 2.5% O2, 2.5% N2O, 0.20% CH4, 0.096% H2, and 0.023% CO with an average recovery of 95 14% of the injected gas volume

Flow injection preconcentration system using a new functionalized resin for determination of cadmium and nickel in tobacco samples

International Nuclear Information System (INIS)

Lemos, Valfredo Azevedo; Novaes, Cleber Galvao; Lima, Adriana da Silva; Vieira, Daniel Rodrigues

2008-01-01

A solid-phase extraction method combined with flow injection (FI) on-line flame atomic absorption spectrometry (FAAS) for the determination of cadmium and nickel in tobacco samples is presented. The 2-aminothiophenol functionalized Amberlite XAD-4 (AT-XAD) resin was synthesized by covalent coupling of the ligand with the copolymer through a methylene group. A minicolumn packed with AT-XAD was connected into the automated on-line preconcentration system. Elution of metal ions from minicolumn can be made with 0.50 mol L -1 hydrochloric acid solution. With a consumption of 21.0 mL of sample solution, detection limits (3 s) of 0.3 (Cd) and 0.8 μg L -1 (Ni) were achieved at a sample throughput of 18 h -1 . Enrichment factors (EF) of 99 (cadmium) and 43 (nickel) were obtained compared with the slope of the linear portion of the calibration curves before and after preconcentration. The contents of Cd and Ni in a certified reference material (NIST 1570a, spinach leaves) determined by the present method was in good agreement with the certified value. The developed procedure was also successfully applied to the determination of Cd and Ni in local tobacco samples

High-performance serial block-face SEM of nonconductive biological samples enabled by focal gas injection-based charge compensation.

Science.gov (United States)

Deerinck, T J; Shone, T M; Bushong, E A; Ramachandra, R; Peltier, S T; Ellisman, M H

2018-05-01

A longstanding limitation of imaging with serial block-face scanning electron microscopy is specimen surface charging. This charging is largely due to the difficulties in making biological specimens and the resins in which they are embedded sufficiently conductive. Local accumulation of charge on the specimen surface can result in poor image quality and distortions. Even minor charging can lead to misalignments between sequential images of the block-face due to image jitter. Typically, variable-pressure SEM is used to reduce specimen charging, but this results in a significant reduction to spatial resolution, signal-to-noise ratio and overall image quality. Here we show the development and application of a simple system that effectively mitigates specimen charging by using focal gas injection of nitrogen over the sample block-face during imaging. A standard gas injection valve is paired with a precisely positioned but retractable application nozzle, which is mechanically coupled to the reciprocating action of the serial block-face ultramicrotome. This system enables the application of nitrogen gas precisely over the block-face during imaging while allowing the specimen chamber to be maintained under high vacuum to maximise achievable SEM image resolution. The action of the ultramicrotome drives the nozzle retraction, automatically moving it away from the specimen area during the cutting cycle of the knife. The device described was added to a Gatan 3View system with minimal modifications, allowing high-resolution block-face imaging of even the most charge prone of epoxy-embedded biological samples. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

Effects of Direct Fuel Injection Strategies on Cycle-by-Cycle Variability in a Gasoline Homogeneous Charge Compression Ignition Engine: Sample Entropy Analysis

Directory of Open Access Journals (Sweden)

Jacek Hunicz

2015-01-01

Full Text Available In this study we summarize and analyze experimental observations of cyclic variability in homogeneous charge compression ignition (HCCI combustion in a single-cylinder gasoline engine. The engine was configured with negative valve overlap (NVO to trap residual gases from prior cycles and thus enable auto-ignition in successive cycles. Correlations were developed between different fuel injection strategies and cycle average combustion and work output profiles. Hypothesized physical mechanisms based on these correlations were then compared with trends in cycle-by-cycle predictability as revealed by sample entropy. The results of these comparisons help to clarify how fuel injection strategy can interact with prior cycle effects to affect combustion stability and so contribute to design control methods for HCCI engines.

Large-Signal Injection-Level Spectroscopy of Impurities in Silicon

International Nuclear Information System (INIS)

Ahrenkiel, R.K.; Johnston, S.W.

1998-01-01

Deep level defects in silicon are identified by measuring the recombination lifetime as a function of the injection level. The basic models for recombination at deep and shallow centers is developed. The defect used for the theoretical model is the well-known interstitial Fe ion in silicon. Data are presented on silicon samples ranging in defect content from intentionally Fe-doped samples to an ultra-pure float-zone grown sample. These data are analyzed in terms of the injection-level spectroscopy model

Development of a flow method for the determination of phosphate in estuarine and freshwaters-Comparison of flow cells in spectrophotometric sequential injection analysis

International Nuclear Information System (INIS)

Mesquita, Raquel B.R.; Ferreira, M. Teresa S.O.B.; Toth, Ildiko V.; Bordalo, Adriano A.; McKelvie, Ian D.; Rangel, Antonio O.S.S.

2011-01-01

Highlights: → Sequential injection determination of phosphate in estuarine and freshwaters. → Alternative spectrophotometric flow cells are compared. → Minimization of schlieren effect was assessed. → Proposed method can cope with wide salinity ranges. → Multi-reflective cell shows clear advantages. - Abstract: A sequential injection system with dual analytical line was developed and applied in the comparison of two different detection systems viz; a conventional spectrophotometer with a commercial flow cell, and a multi-reflective flow cell coupled with a photometric detector under the same experimental conditions. The study was based on the spectrophotometric determination of phosphate using the molybdenum-blue chemistry. The two alternative flow cells were compared in terms of their response to variation of sample salinity, susceptibility to interferences and to refractive index changes. The developed method was applied to the determination of phosphate in natural waters (estuarine, river, well and ground waters). The achieved detection limit (0.007 μM PO 4 3- ) is consistent with the requirement of the target water samples, and a wide quantification range (0.024-9.5 μM) was achieved using both detection systems.

Development of a flow method for the determination of phosphate in estuarine and freshwaters-Comparison of flow cells in spectrophotometric sequential injection analysis

Energy Technology Data Exchange (ETDEWEB)

Mesquita, Raquel B.R. [CBQF/Escola Superior de Biotecnologia, Universidade Catolica Portuguesa, R. Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal); Laboratory of Hydrobiology, Institute of Biomedical Sciences Abel Salazar (ICBAS) and Institute of Marine Research (CIIMAR), Universidade do Porto, Lg. Abel Salazar 2, 4099-003 Porto (Portugal); Ferreira, M. Teresa S.O.B. [CBQF/Escola Superior de Biotecnologia, Universidade Catolica Portuguesa, R. Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal); Toth, Ildiko V. [REQUIMTE, Departamento de Quimica, Faculdade de Farmacia, Universidade de Porto, Rua Anibal Cunha, 164, 4050-047 Porto (Portugal); Bordalo, Adriano A. [Laboratory of Hydrobiology, Institute of Biomedical Sciences Abel Salazar (ICBAS) and Institute of Marine Research (CIIMAR), Universidade do Porto, Lg. Abel Salazar 2, 4099-003 Porto (Portugal); McKelvie, Ian D. [School of Chemistry, University of Melbourne, Victoria 3010 (Australia); Rangel, Antonio O.S.S., E-mail: aorangel@esb.ucp.pt [CBQF/Escola Superior de Biotecnologia, Universidade Catolica Portuguesa, R. Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal)

2011-09-02

Highlights: {yields} Sequential injection determination of phosphate in estuarine and freshwaters. {yields} Alternative spectrophotometric flow cells are compared. {yields} Minimization of schlieren effect was assessed. {yields} Proposed method can cope with wide salinity ranges. {yields} Multi-reflective cell shows clear advantages. - Abstract: A sequential injection system with dual analytical line was developed and applied in the comparison of two different detection systems viz; a conventional spectrophotometer with a commercial flow cell, and a multi-reflective flow cell coupled with a photometric detector under the same experimental conditions. The study was based on the spectrophotometric determination of phosphate using the molybdenum-blue chemistry. The two alternative flow cells were compared in terms of their response to variation of sample salinity, susceptibility to interferences and to refractive index changes. The developed method was applied to the determination of phosphate in natural waters (estuarine, river, well and ground waters). The achieved detection limit (0.007 {mu}M PO{sub 4}{sup 3-}) is consistent with the requirement of the target water samples, and a wide quantification range (0.024-9.5 {mu}M) was achieved using both detection systems.

The 150 ns detector project: Prototype preamplifier results

Science.gov (United States)

Warburton, W. K.; Russell, S. R.; Kleinfelder, Stuart A.

1994-08-01

The long-term goal of the 150 ns detector project is to develop a pixel area detector capable of 6 MHz frame rates (150 ns/frame). Our milestones toward this goal are: a single pixel, 1×256 1D and 8×8 2D detectors, 256×256 2D detectors and, finally, 1024 × 1024 2D detectors. The design strategy is to supply a complete electronics chain (resetting preamp, selectable gain amplifier, analog-to-digital converter (ADC), and memory) for each pixel. In the final detectors these will all be custom integrated circuits. The front-end preamplifiers are integrated first, since their design and performance are the most unusual and also critical to the project's success. Similarly, our early work is concentrated on devising and perfecting detector structures. In this paper we demonstrate the performance of prototypes of our integrated preamplifiers. While the final design will have 64 preamps to a chip, including a switchable gain stage, the prototypes were integrated 8 channels to a "Tiny Chip" and tested in 4 configurations (feedback capacitor Cf equal 2.5 or 4.0 pF, output directly or through a source follower). These devices have been tested thoroughly for reset settling times, gain, linearity, and electronic noise. They generally work as designed, being fast enough to easily integrate detector charge, settle, and reset in 150 ns. Gain and linearity appear to be acceptable. Current values of electronic noise, in double-sampling mode, are about twice the design goal of {2}/{3} of a single photon at 6 keV. We expect this figure to improve with the addition of the onboard amplifier stage and improved packaging. Our next test chip will include these improvements and allow testing with our first detector samples, which will be 1×256 (50 μm wide pixels) and 8×8 (1 mm 2 pixels) element detector on 1 mm thick silicon.

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)

Calculation of depleted uranium concentration in dental fillings samples using the nuclear track detector CR-39

International Nuclear Information System (INIS)

Mahdi, K. H.; Subhi, A. T.; Tawfiq, N. F.

2012-12-01

The purpose of this study is to determine the concentration of depleted uranium in dental fillings samples, which were obtained some hospital and dental office, sale of materials deployed in Iraq. 8 samples were examined from two different fillings and lead-filling (amalgam) and composite filling (plastic). concentrations of depleted uranium were determined in these samples using a nuclear track detector CR-39 through the recording of the tracks left by of fragments of fission resulting from the reaction 2 38U (n, f). The samples are bombarded by neutrons emitted from the neutron source (2 41A m-Be) with flux of ( 10 5 n. cm- 2. s -1 ). The period of etching to show the track of fission fragments is 5 hours using NaOH solution with normalization (6.25N), and temperature (60 o C ). Concentration of depleted uranium were calculated by comparison with standard samples. The result that obtained showed that the value of the weighted average for concentration of uranium in the samples fillings (5.54± 1.05) ppm lead to thr filling (amalgam) and (5.33±0.6) ppm of the filling composite (plastic). The hazard- index, the absorbed dose and the effective dose for these concentration were determined. The obtained results of the effective dose for each of the surface of the bone and skin (as the areas most affected by this compensation industrial) is (0.56 mSv / y) for the batting lead (amalgam) and (0.54 mSv / y) for the filling composite (plastic). From the results of study it was that the highest rate is the effective dose to a specimen amalgam filling (0.68 mSv / y) which is less than the allowable limit for exposure of the general people set the World Health Organization (WHO), a (1 mSv / y). (Author)

Micro-powder injection moulding of tungsten

International Nuclear Information System (INIS)

Zeep, B.

2007-12-01

For He-cooled Divertors as integral components of future fusion power plants, about 300000 complex shaped tungsten components are to be fabricated. Tungsten is the favoured material because of its excellent properties (high melting point, high hardness, high sputtering resistance, high thermal conductivity). However, the material's properties cause major problems for large scale production of complex shaped components. Due to the resistance of tungsten to mechanical machining, new fabrication technologies have to be developed. Powder injection moulding as a well established shaping technology for a large scale production of complex or even micro structured parts might be a suitable method to produce tungsten components for fusion applications but is not yet commercially available. The present thesis is dealing with the development of a powder injection moulding process for micro structured tungsten components. To develop a suitable feedstock, the powder particle properties, the binder formulation and the solid load were optimised. To meet the requirements for a replication of micro patterned cavities, a special target was to define the smallest powder particle size applicable for micro-powder injection moulding. To investigate the injection moulding performance of the developed feedstocks, experiments were successfully carried out applying diverse cavities with structural details in micro dimension. For debinding of the green bodies, a combination of solvent debinding and thermal debinding has been adopted for injection moulded tungsten components. To develop a suitable debinding strategy, a variation of the solvent debinding time, the heating rate and the binder formulation was performed. For investigating the thermal consolidation behaviour of tungsten components, sinter experiments were carried out applying tungsten powders suitable for micro-powder injection moulding. First mechanical tests of the sintered samples showed promising material properties such as a

Study of CdTe:Cl and CdZnTe detectors for medical multi-slices X-ray Computed Tomography

International Nuclear Information System (INIS)

Ricq, St.

1999-01-01

The application of CdTe and CdZnTe detectors to medical X-ray Computed Tomography have been investigated. Different electrodes (Au, Pt, In) have been deposited on CdZnTe HPBM and on CdTe:ClTHM. Their injection properties have been determined with Current-Voltage characteristics. Under X-ray in CT conditions, injection currents measurements reveal trapped carriers space-charges formation. The same way, the comparisons of the responses to X-beam cut-off with various injection possibilities enable to follow the space-charges evolutions and then to determine the predominant traps types. Nevertheless, both hole and electron traps are responsible for the memory effect e.g. the currents levels dependence with irradiation history. This effect is noticed in particular on responses to fast flux variations that simulate scanner's conditions. Trap levels probably corresponding to native defects are responsible for these limitations. In order to make such detectors suitable for X-ray Computed Tomography, significant progresses in CdTe for CdZnTe crystal growth with an important defects densities reduction (factor 10), or possibly counting mode operation, seem necessary. (author)

The Belle II DEPFET pixel detector

Energy Technology Data Exchange (ETDEWEB)

Moser, Hans-Günther, E-mail: moser@mpp.mpg.de

2016-09-21

The Belle II experiment at KEK (Tsukuba, Japan) will explore heavy flavour physics (B, charm and tau) at the starting of 2018 with unprecedented precision. Charged particles are tracked by a two-layer DEPFET pixel device (PXD), a four-layer silicon strip detector (SVD) and the central drift chamber (CDC). The PXD will consist of two layers at radii of 14 mm and 22 mm with 8 and 12 ladders, respectively. The pixel sizes will vary, between 50 μm×(55–60) μm in the first layer and between 50 μm×(70–85) μm in the second layer, to optimize the charge sharing efficiency. These innermost layers have to cope with high background occupancy, high radiation and must have minimal material to reduce multiple scattering. These challenges are met using the DEPFET technology. Each pixel is a FET integrated on a fully depleted silicon bulk. The signal charge collected in the ‘internal gate’ modulates the FET current resulting in a first stage amplification and therefore very low noise. This allows very thin sensors (75 μm) reducing the overall material budget of the detector (0.21% X{sub 0}). Four fold multiplexing of the column parallel readout allows read out a full frame of the pixel matrix in only 20 μs while keeping the power consumption low enough for air cooling. Only the active electronics outside the detector acceptance has to be cooled actively with a two phase CO{sub 2} system. Furthermore the DEPFET technology offers the unique feature of an electronic shutter which allows the detector to operate efficiently in the continuous injection mode of superKEKB.

Scintillation detectors for radon-222 in air and water

International Nuclear Information System (INIS)

Mastinu, G.G.

1980-01-01

A scintillation detector and an emanation circuit that enable sensitive measurements of 222 Rn in water, in field practice, and in laboratory routine have been developed. Activities as low as 0.1 pCi per sample can be measured with a very simple procedure. The detector is also well suited to measure 222 Rn in air at concentrations down to 0.001 pCi/liter if a large-size detector is used

Performance comparison of scintillators for alpha particle detectors

Energy Technology Data Exchange (ETDEWEB)

Morishita, Yuki [Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, Aichi 461-8673 (Japan); Japan Atomic Energy Agency, Muramatsu 4-33, Tokai-mura, Ibaraki 319-1194 (Japan); Yamamoto, Seiichi [Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, Aichi 461-8673 (Japan); Izaki, Kenji [Japan Atomic Energy Agency, Muramatsu 4-33, Tokai-mura, Ibaraki 319-1194 (Japan); Kaneko, Junichi H.; Toui, Kohei; Tsubota, Youichi; Higuchi, Mikio [Graduate School of Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)

2014-11-11

Scintillation detectors for alpha particles are often used in nuclear fuel facilities. Alpha particle detectors have also become important in the research field of radionuclide therapy using alpha emitters. ZnS(Ag) is the most often used scintillator for alpha particle detectors because its light output is high. However, the energy resolution of ZnS(Ag)-based scintillation detectors is poor because they are not transparent. A new ceramic sample, namely the cerium doped Gd{sub 2}Si{sub 2}O{sub 7} (GPS) scintillator, has been tested as alpha particle detector and its performances have been compared to that one of three different scintillating materials: ZnS(Ag), GAGG and a standard plastic scintillator. The different scintillating materials have been coupled to two different photodetectors, namely a photomultiplier tube (PMT) and a Silicon Photo-multiplier (Si-PM): the performances of each detection system have been compared. Promising results as far as the energy resolution performances (10% with PMT and 14% with Si-PM) have been obtained in the case of GPS and GAGG samples. Considering the quantum efficiencies of the photodetectors under test and their relation to the emission wavelength of the different scintillators, the best results were achieved coupling the GPS with the PMT and the GAGG with the Si-PM.

Effects of Pre and Post-Rigor Marinade Injection on Some Quality Parameters of Longissimus Dorsi Muscles

Science.gov (United States)

Fadıloğlu, Eylem Ezgi; Serdaroğlu, Meltem

2018-01-01

Abstract This study was conducted to evaluate the effects of pre and post-rigor marinade injections on some quality parameters of Longissimus dorsi (LD) muscles. Three marinade formulations were prepared with 2% NaCl, 2% NaCl+0.5 M lactic acid and 2% NaCl+0.5 M sodium lactate. In this study marinade uptake, pH, free water, cooking loss, drip loss and color properties were analyzed. Injection time had significant effect on marinade uptake levels of samples. Regardless of marinate formulation, marinade uptake of pre-rigor samples injected with marinade solutions were higher than post rigor samples. Injection of sodium lactate increased pH values of samples whereas lactic acid injection decreased pH. Marinade treatment and storage period had significant effect on cooking loss. At each evaluation period interaction between marinade treatment and injection time showed different effect on free water content. Storage period and marinade application had significant effect on drip loss values. Drip loss in all samples increased during the storage. During all storage days, lowest CIE L* value was found in pre-rigor samples injected with sodium lactate. Lactic acid injection caused color fade in pre-rigor and post-rigor samples. Interaction between marinade treatment and storage period was found statistically significant (p<0.05). At day 0 and 3, the lowest CIE b* values obtained pre-rigor samples injected with sodium lactate and there were no differences were found in other samples. At day 6, no significant differences were found in CIE b* values of all samples. PMID:29805282

Automatic control and detector for three-terminal resistance measurement

Science.gov (United States)

Fasching, George E.

1976-10-26

A device is provided for automatic control and detection in a three-terminal resistance measuring instrument. The invention is useful for the rapid measurement of the resistivity of various bulk material with a three-terminal electrode system. The device maintains the current through the sample at a fixed level while measuring the voltage across the sample to detect the sample resistance. The three-electrode system contacts the bulk material and the current through the sample is held constant by means of a control circuit connected to a first of the three electrodes and works in conjunction with a feedback controlled amplifier to null the voltage between the first electrode and a second electrode connected to the controlled amplifier output. An A.C. oscillator provides a source of sinusoidal reference voltage of the frequency at which the measurement is to be executed. Synchronous reference pulses for synchronous detectors in the control circuit and an output detector circuit are provided by a synchronous pulse generator. The output of the controlled amplifier circuit is sampled by an output detector circuit to develop at an output terminal thereof a D.C. voltage which is proportional to the sample resistance R. The sample resistance is that segment of the sample between the area of the first electrode and the third electrode, which is connected to ground potential.

Viscous hydrophilic injection matrices for serial crystallography

Directory of Open Access Journals (Sweden)

Gabriela Kovácsová

2017-07-01

Full Text Available Serial (femtosecond crystallography at synchrotron and X-ray free-electron laser (XFEL sources distributes the absorbed radiation dose over all crystals used for data collection and therefore allows measurement of radiation damage prone systems, including the use of microcrystals for room-temperature measurements. Serial crystallography relies on fast and efficient exchange of crystals upon X-ray exposure, which can be achieved using a variety of methods, including various injection techniques. The latter vary significantly in their flow rates – gas dynamic virtual nozzle based injectors provide very thin fast-flowing jets, whereas high-viscosity extrusion injectors produce much thicker streams with flow rates two to three orders of magnitude lower. High-viscosity extrusion results in much lower sample consumption, as its sample delivery speed is commensurate both with typical XFEL repetition rates and with data acquisition rates at synchrotron sources. An obvious viscous injection medium is lipidic cubic phase (LCP as it is used for in meso membrane protein crystallization. However, LCP has limited compatibility with many crystallization conditions. While a few other viscous media have been described in the literature, there is an ongoing need to identify additional injection media for crystal embedding. Critical attributes are reliable injection properties and a broad chemical compatibility to accommodate samples as heterogeneous and sensitive as protein crystals. Here, the use of two novel hydrogels as viscous injection matrices is described, namely sodium carboxymethyl cellulose and the thermo-reversible block polymer Pluronic F-127. Both are compatible with various crystallization conditions and yield acceptable X-ray background. The stability and velocity of the extruded stream were also analysed and the dependence of the stream velocity on the flow rate was measured. In contrast with previously characterized injection media, both new

Sequential injection chromatography with post-column reaction/derivatization for the determination of transition metal cations in natural water samples.

Science.gov (United States)

Horstkotte, Burkhard; Jarošová, Patrícia; Chocholouš, Petr; Sklenářová, Hana; Solich, Petr

2015-05-01

In this work, the applicability of Sequential Injection Chromatography for the determination of transition metals in water is evaluated for the separation of copper(II), zinc(II), and iron(II) cations. Separations were performed using a Dionex IonPAC™ guard column (50mm×2mm i.d., 9 µm). Mobile phase composition and post-column reaction were optimized by modified SIMPLEX method with subsequent study of the concentration of each component. The mobile phase consisted of 2,6-pyridinedicarboxylic acid as analyte-selective compound, sodium sulfate, and formic acid/sodium formate buffer. Post-column addition of 4-(2-pyridylazo)resorcinol was carried out for spectrophotometric detection of the analytes׳ complexes at 530nm. Approaches to achieve higher robustness, baseline stability, and detection sensitivity by on-column stacking of the analytes and initial gradient implementation as well as air-cushion pressure damping for post-column reagent addition were studied. The method allowed the rapid separation of copper(II), zinc(II), and iron(II) within 6.5min including pump refilling and aspiration of sample and 1mmol HNO3 for analyte stacking on the separation column. High sensitivity was achieved applying an injection volume of up to 90µL. A signal repeatability of<2% RSD of peak height was found. Analyte recovery evaluated by spiking of different natural water samples was well suited for routine analysis with sub-micromolar limits of detection. Copyright © 2015 Elsevier B.V. All rights reserved.

Reactor antineutrino detector iDREAM.

Science.gov (United States)

Gromov, M. B.; Lukyanchenko, G. A.; Novikova, G. J.; Obinyakov, B. A.; Oralbaev, A. Y.; Skorokhvatov, M. D.; Sukhotin, S. V.; Chepurnov, A. S.; Etenko, A. V.

2017-09-01

Industrial Detector for Reactor Antineutrino Monitoring (iDREAM) is a compact (≈ 3.5m 2) industrial electron antineutrino spectrometer. It is dedicated for remote monitoring of PWR reactor operational modes by neutrino method in real-time. Measurements of antineutrino flux from PWR allow to estimate a fuel mixture in active zone and to check the status of the reactor campaign for non-proliferation purposes. LAB-based gadolinium doped scintillator is exploited as a target. Multizone architecture of the detector with gamma-catcher surrounding fiducial volume and plastic muon veto above and below ensure high efficiency of IBD detection and background suppression. DAQ is based on Flash ADC with PSD discrimination algorithms while digital trigger is programmable and flexible due to FPGA. The prototype detector was started up in 2014. Preliminary works on registration Cerenkov radiation produced by cosmic muons were established with distilled water inside the detector in order to test electronic and slow control systems. Also in parallel a long-term measurements with different scintillator samples were conducted.

CdTe and CdZnTe detectors behavior in X-ray computed tomography conditions

CERN Document Server

Ricq, S; Garcin, M

2000-01-01

The application of CdTe and CdZnTe 2D array detectors for medical X-ray Computed Tomography (XCT) is investigated. Different metallic electrodes have been deposited on High-Pressure Bridgman Method CdZnTe and on Traveling Heater Method CdTe:Cl. These detectors are exposed to X-rays in the CT irradiation conditions and are characterized experimentally in current mode. Detectors performances such as sensitivity and response speed are studied. They are correlated with charge trapping and de-trapping. The trapped carrier space charges may influence the injection from the electrodes. This enables one to get information on the nature of the predominant levels involved. The performances achieved are encouraging: dynamic ranges higher than 4 decades and current decreases of 3 decades in 4 ms after X-ray beam cut-off are obtained. Nevertheless, these detectors are still limited by high trap densities responsible for the memory effect that makes them unsuitable for XCT.

Neutron detector for detecting rare events of spontaneous fission

International Nuclear Information System (INIS)

Ter-Akop'yan, G.M.; Popeko, A.G.; Sokol, E.A.; Chelnokov, L.P.; Smirnov, V.I.; Gorshkov, V.A.

1981-01-01

The neutron detector for registering rare events of spontaneous fission by detecting multiple neutron emission is described. The detector represents a block of plexiglas of 550 mm diameter and 700 mm height in the centre of which there is a through 160 mm diameter channel for the sample under investigation. The detector comprises 56 3 He filled counters (up to 7 atm pressure) with 1% CO 2 addition. The counters have a 500 mm length and a 32 mm diameter. The sampling of fission events is realized by an electron system which allows determining the number of detected neutrons, numbers of operated counters, signal amplitude and time for fission event detecting. A block diagram of a neutron detector electron system is presented and its operation principle is considered. For protection against cosmic radiation the detector is surronded by a system of plastic scintillators and placed behind the concrete shield of 6 m thickness. The results of measurements of background radiation are given. It has been found that the background radiation of single neutron constitutes about 150 counts per hour, the detecting efficiency of single neutron equals 0.483 +- 0.005, for a 10l detector sensitive volume. By means of the detector described the parameters of multiplicity distribution of prompt neutrons for 256 Fm spontaneous fission are measured. The average multiplicity equals 3.59+-0.06 the dispersion being 2.30+-0.65

Dual-Energy Semiconductor Detector of X-rays and Gamma Radiation

Directory of Open Access Journals (Sweden)

Brodyn, M.S.

2014-03-01

Full Text Available Analysis of the major types of ionizing radiation detectors, their advantages and disadvantages are presented. Application of ZnSe-based semiconductor detector in high temperature environment is substantiated. Different forms of ZnSe-based detector samples and double-crystal scheme for registration of X- and gamma rays in a broad energy range were used . Based on the manufactured simulator device, the study sustains the feasibility of the gamma quanta recording by a high-resistance ZnSe-based detector operating in a perpulse mode.

The Inner Detector software moves to Geant4

CERN Multimedia

Elsing, M

2004-01-01

2004 is a year of change and of several major milestones for the Inner Detector software. The first of these milestones was met in March when a set of test events was successfully processed through Geant4 and afterwards through the full Inner Detector offline software chain. In the picture, a reconstructed single muon event from this test sample is displayed in different projections. Even though this looks almost trivial, it required the successful integration of several new software components besides Geant4 into the Inner Detector code. A new ATLAS wide Detector Description software package called GeoModel has been fully deployed in the Inner Detector as the single source of geometry information for both the simulation and the reconstruction. New code to emulate the digitization for all detectors and a new data model have been put in place to cope with the new simulation input. And finally the two major offline reconstruction packages, namely xKalman and iPatRec, were migrated to use the new Inner Detector ...

HPGe detector shielding adjustment

International Nuclear Information System (INIS)

Trnkova, L.; Rulik, P.

2008-01-01

Low-level background shielding of HPGe detectors is used mainly for environmental samples with very low content of radionuclides. National Radiation Protection Institute (SURO) in Prague is equipped with 14 HPGe detectors with relative efficiency up to 150%. The detectors are placed in a room built from materials with low content of natural radionuclides and equipped with a double isolation of the floor against radon. Detectors themselves are placed in lead or steel shielding. Steel shielding with one of these detectors with relative efficiency of 100% was chosen to be rebuilt to achieve lower minimum detectable activity (MDA). Additional lead and copper shielding was built up inside the original steel shielding to reduce the volume of the inner space and filled with nitrogen by means of evaporating liquid nitrogen. The additional lead and copper shielding, consequent reduction of the inner volume and supply of evaporated nitrogen, caused a decrease of the background count and accordingly MDA values as well. The effect of nitrogen evaporation on the net areas of peaks belonging to radon daughters is significant. The enhanced shielding adjustment has the biggest influence in low energy range, what can be seen in collected data. MDA values in energy range from 30 keV to 400 keV decreased to 0.65-0.85 of original value, in energy range from 400 keV to 2 MeV they fell to 0.70-0.97 of original value. (authors)

Sequential determination of multi-nutrient elements in natural water samples with a reverse flow injection system.

Science.gov (United States)

Lin, Kunning; Ma, Jian; Yuan, Dongxing; Feng, Sichao; Su, Haitao; Huang, Yongming; Shangguan, Qipei

2017-05-15

An integrated system was developed for automatic and sequential determination of NO 2 - , NO 3 - , PO 4 3- , Fe 2+ , Fe 3+ and Mn 2+ in natural waters based on reverse flow injection analysis combined with spectrophotometric detection. The system operation was controlled by a single chip microcomputer and laboratory-programmed software written in LabVIEW. The experimental parameters for each nutrient element analysis were optimized based on a univariate experimental design, and interferences from common ions were evaluated. The upper limits of the linear range (along with detection limit, µmolL -1 ) of the proposed method was 20 (0.03), 200 (0.7), 12 (0.3), 5 (0.03), 5 (0.03), 9 (0.2) µmolL -1 , for NO 2 - , NO 3 - , PO 4 3- , Fe 2+ , Fe 3+ and Mn 2+ , respectively. The relative standard deviations were below 5% (n=9-13) and the recoveries varied from 88.0±1.0% to 104.5±1.0% for spiked water samples. The sample throughput was about 20h -1 . This system has been successfully applied for the determination of multi-nutrient elements in different kinds of water samples and showed good agreement with reference methods (slope 1.0260±0.0043, R 2 =0.9991, n=50). Copyright © 2017 Elsevier B.V. All rights reserved.

Down scaled Kjeldahl digestion and flow injection conductometric system for determination of protein content in some traditional northern Thai foods.

Science.gov (United States)

Yanu, Pattama; Jakmunee, Jaroon

2017-09-01

A flow injection conductometric (FIC) system for determination of total Kjeldahl nitrogen (TKN) was developed for estimating total protein content in food. A small scale Kjeldahl digestion was performed with a short digestion time of only 20min. The digested solution was injected into the FIC system, and TKN was converted to ammonia gas in an alkaline donor stream of the system. The gas diffused through a membrane and dissolved into an acceptor stream causing an increase in conductivity as detected by a detector and recorded as a peak. Under the optimum condition, a linear calibration graph in the range of 4.00-100.00mgL -1 was obtained with LOD of 0.05mgL -1 . A good precision (0.04% RSD, n=11, 30.00mgNL -1 ) and high sample throughput of 72h -1 was achieved. The method was applied for determination of protein in some traditional northern Thai foods, revealing that they are good sources of proteins. Copyright © 2017 Elsevier Ltd. All rights reserved.

In-situ X-ray diffraction system using sources and detectors at fixed angular positions

Science.gov (United States)

Gibson, David M [Voorheesville, NY; Gibson, Walter M [Voorheesville, NY; Huang, Huapeng [Latham, NY

2007-06-26

An x-ray diffraction technique for measuring a known characteristic of a sample of a material in an in-situ state. The technique includes using an x-ray source for emitting substantially divergent x-ray radiation--with a collimating optic disposed with respect to the fixed source for producing a substantially parallel beam of x-ray radiation by receiving and redirecting the divergent paths of the divergent x-ray radiation. A first x-ray detector collects radiation diffracted from the sample; wherein the source and detector are fixed, during operation thereof, in position relative to each other and in at least one dimension relative to the sample according to a-priori knowledge about the known characteristic of the sample. A second x-ray detector may be fixed relative to the first x-ray detector according to the a-priori knowledge about the known characteristic of the sample, especially in a phase monitoring embodiment of the present invention.

Energy dispersive X-ray fluorescence from useless tyres samples with a Si PIN detector; Fluorescencia de raios X por dispersao em energia de amostras de pneus inserviveis com detector de Si-PIN

Energy Technology Data Exchange (ETDEWEB)

Lopes, Fabio; Scheibel, Viviane [Universidade Estadual de Londrina, PR (Brazil). Dept. de Fisica. Lab. de Fisica Nuclear Aplicada]. E-mail: bonn@uel.br; Melquiades, Fabio Luiz [Universidade Estadual do Centro-Oeste, Guarapuava, PR (Brazil). Dept. de Fisica; Moraes, Liz Mary Bueno de [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Instrumentacao Nuclear

2005-07-01

The concentration of Zn from discard tyre samples is of environmental interest, since on its production are used S for the rubber vulcanization process, and Zn O as reaction catalyze. The useless tyres are been used for asphalt pave, burn in cement industry and thermoelectric power plant and in erosion control of agriculture areas. Analyses of these samples requires frequently chemical digestion that is expensive and take a long time. Trying to eliminate these limitations, the objective of this work was use Energy Dispersive X Ray Fluorescence technique (EDXRF) with a portable system as the technique is multi elementary and needs a minimum sample preparation. Five useless tyres samples were grind in a knife mill and after this in a cryogenic mill, and analyzed in pellets form, using a X ray mini tube (Ag target, Mo {sub l}ter, 25 kV/20 {sub A}) for 200 s and a Si-PIN semiconductor detector coupled to a multichannel analyzer. Were obtained Zn concentrations in the range of 40.6 to 44.2 {sub g} g{sub 1}, representing nearly 0.4. (author)

PROTVINO: Mass-production of scintillator tiles by injection moulding

International Nuclear Information System (INIS)

Anon.

1994-01-01

The technique of the segmented sandwich-calorimeters with wavelength-shifting readout, especially its large-scale application in big detectors, requires enormous quantities of a cheap scintillator tiles of moderate dimensions (20 x 20 cm 2 ). Initial trials carried out in the Institute for High Energy Physics (IHEP), Protvino, Russia almost ten years ago showed that manufacturing such scintillator tiles was possible using an ordinary commercially-available granulated optical polystyrene, an existing technology of plastic dyeing, and a well-known process of the injection moulding, used to produce plastic goods (like buttons!)

Development of CVD diamond radiation detectors

CERN Document Server

Adam, W; Berdermann, E; Bogani, F; Borchi, E; Bruzzi, Mara; Colledani, C; Conway, J; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fisch, D; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Grigoriev, E A; Hallewell, G D; Hall-Wilton, R; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Kass, R; Knöpfle, K T; Krammer, Manfred; Manfredi, P F; Meier, D; Mishina, M; Le Normand, F; Pan, L S; Pernegger, H; Pernicka, Manfred; Pirollo, S; Re, V; Riester, J L; Roe, S; Roff, D G; Rudge, A; Schnetzer, S R; Sciortino, S; Speziali, V; Stelzer, H; Stone, R; Tapper, R J; Tesarek, R J; Thomson, G B; Trawick, M L; Trischuk, W; Turchetta, R; Walsh, A M; Wedenig, R; Weilhammer, Peter; Ziock, H J; Zoeller, M M

1998-01-01

Diamond is a nearly ideal material for detecting ionizing radiation. Its outstanding radiation hardness, fast charge collection and low leakage current allow a diamond detector to be used in high ra diation, high temperature and in aggressive chemical media. We have constructed charged particle detectors using high quality CVD diamond. Characterization of the diamond samples and various detect ors are presented in terms of collection distance, $d=\\mu E \\tau$, the average distance electron-hole pairs move apart under the influence of an electric field, where $\\mu$ is the sum of carrier mo bilities, $E$ is the applied electric field, and $\\tau$ is the mobility weighted carrier lifetime. Over the last two years the collection distance increased from $\\sim$ 75 $\\mu$m to over 200 $\\mu$ m. With this high quality CVD diamond a series of micro-strip and pixel particle detectors have been constructed. These devices were tested to determine their position resolution and signal to n oise performance. Diamond detectors w...

Detectors for proton counting. Si-APD and scintillation detectors

International Nuclear Information System (INIS)

Kishimoto, Shunji

2008-01-01

Increased intensity of synchrotron radiation requests users to prepare photon pulse detectors having higher counting rates. As detectors for photon counting, silicon-avalanche photodiode (Si-APD) and scintillation detectors were chosen for the fifth series of detectors. Principle of photon detection by pulse and need of amplification function of the detector were described. Structure and working principle, high counting rate measurement system, bunch of electrons vs. counting rate, application example of NMR time spectroscopy measurement and comments for users were described for the Si-APD detector. Structure of scintillator and photomultiplier tube, characteristics of scintillator and performance of detector were shown for the NaI detector. Future development of photon pulse detectors was discussed. (T. Tanaka)

Simultaneous CT and SPECT tomography using CZT detectors

Science.gov (United States)

Paulus, Michael J.; Sari-Sarraf, Hamed; Simpson, Michael L.; Britton, Jr., Charles L.

2002-01-01

A method for simultaneous transmission x-ray computed tomography (CT) and single photon emission tomography (SPECT) comprises the steps of: injecting a subject with a tracer compound tagged with a .gamma.-ray emitting nuclide; directing an x-ray source toward the subject; rotating the x-ray source around the subject; emitting x-rays during the rotating step; rotating a cadmium zinc telluride (CZT) two-sided detector on an opposite side of the subject from the source; simultaneously detecting the position and energy of each pulsed x-ray and each emitted .gamma.-ray captured by the CZT detector; recording data for each position and each energy of each the captured x-ray and .gamma.-ray; and, creating CT and SPECT images from the recorded data. The transmitted energy levels of the x-rays lower are biased lower than energy levels of the .gamma.-rays. The x-ray source is operated in a continuous mode. The method can be implemented at ambient temperatures.

Stability of penicillin G sodium diluted with 0.9% sodium chloride injection or 5% dextrose injection and stored in polyvinyl chloride bag containers and elastomeric pump containers.

Science.gov (United States)

Hossain, Mirza Akram; Friciu, Mihaela; Aubin, Sebastien; Leclair, Grégoire

2014-04-15

The stability of penicillin G sodium solutions stored in polyvinyl chloride (PVC) bags or elastomeric pump containers was studied. Test samples were prepared by diluting powdered penicillin G sodium (10 million units/10-mL vial) to solutions of 2,500 or 50,000 units/mL with 0.9% sodium chloride injection or 5% dextrose injection. The preparations were transferred to 250-mL PVC bags and elastomeric pump containers. All samples were prepared in triplicate and stored at 5°C. Chemical stability was measured by a stability-indicating high-performance liquid chromatographic (HPLC) assay and by pH evaluation. Particulate matter was evaluated according to compendial standards using a light-obscuration particle count test. Preparations were visually examined throughout the study. After 21 days of storage, all test samples remained chemically stable, with an HPLC assay recovery value of more than 90% of the initial value. After 28 days, all samples prepared with either diluent and stored in PVC bags, as well as the samples diluted to 2,500 units/mL with sodium chloride injection and stored in elastomeric pump containers, did not meet the recovery acceptance limit. For all test samples, the mean pH consistently decreased during storage, from about 6.4 to about 5.5. Particle counts remained acceptable throughout the study, and no change in appearance was observed. Penicillin G for injection (2,500 and 50,000 units/mL) diluted in 0.9% sodium chloride injection or 5% dextrose injection and stored at 5°C in PVC containers or elastomeric pump containers was physically and chemically stable for a period of at least 21 days.

Variable sampling-time technique for improving count rate performance of scintillation detectors

International Nuclear Information System (INIS)

Tanaka, E.; Nohara, N.; Murayama, H.

1979-01-01

A new technique is presented to improve the count rate capability of a scintillation spectrometer or a position sensitive detector with minimum loss of resolution. The technique is based on the combination of pulse shortening and selective integration in which the integration period is not fixed but shortened by the arrival of the following pulse. Theoretical analysis of the degradation of the statiscal component of resolution is made for the proposed system with delay line pulse shortening, and the factor of resolution loss is formulated as a function of the input pulse rate. A new method is also presented for determining the statistical component of resolution separately from the non-statistical system resolution. Preliminary experiments with a NaI(Tl) detector have been carried out, the results of which are consistent with the theoretical prediction. However, due to the non-exponential scintillation decay of the NaI(Tl) crystal, a simple delay line clipping is not satisfactory, and an RC high-pass filter has been added, which results in further degradation of the statistical resolution. (Auth.)

Injection-induced moment release can also be aseismic

Science.gov (United States)

McGarr, Arthur; Barbour, Andrew J.

2018-01-01

The cumulative seismic moment is a robust measure of the earthquake response to fluid injection for injection volumes ranging from 3100 to about 12 million m3. Over this range, the moment release is limited to twice the product of the shear modulus and the volume of injected fluid. This relation also applies at the much smaller injection volumes of the field experiment in France reported by Guglielmi, et al. (2015) and laboratory experiments to simulate hydraulic fracturing described by Goodfellow, et al. (2015). In both of these studies, the relevant moment release for comparison with the fluid injection was aseismic and consistent with the scaling that applies to the much larger volumes associated with injection-induced earthquakes with magnitudes extending up to 5.8. Neither the micro-earthquakes, at the site in France, nor the acoustic emission in the laboratory samples contributed significantly to the deformation due to fluid injection.

Toward high-resolution NMR spectroscopy of microscopic liquid samples

Energy Technology Data Exchange (ETDEWEB)

Butler, Mark C.; Mehta, Hardeep S.; Chen, Ying; Reardon, Patrick N.; Renslow, Ryan S.; Khbeis, Michael; Irish, Duane; Mueller, Karl T.

2017-01-01

A longstanding limitation of high-resolution NMR spectroscopy is the requirement for samples to have macroscopic dimensions. Commercial probes, for example, are designed for volumes of at least 5 mL, in spite of decades of work directed toward the goal of miniaturization. Progress in miniaturizing inductive detectors has been limited by a perceived need to meet two technical requirements: (1) minimal separation between the sample and the detector, which is essential for sensitivity, and (2) near-perfect magnetic-field homogeneity at the sample, which is typically needed for spectral resolution. The first of these requirements is real, but the second can be relaxed, as we demonstrate here. By using pulse sequences that yield high-resolution spectra in an inhomogeneous field, we eliminate the need for near-perfect field homogeneity and the accompanying requirement for susceptibility matching of microfabricated detector components. With this requirement removed, typical imperfections in microfabricated components can be tolerated, and detector dimensions can be matched to those of the sample, even for samples of volume << 5 uL. Pulse sequences that are robust to field inhomogeneity thus enable small-volume detection with optimal sensitivity. We illustrate the potential of this approach to miniaturization by presenting spectra acquired with a flat-wire detector that can easily be scaled to subnanoliter volumes. In particular, we report high-resolution NMR spectroscopy of an alanine sample of volume 500 pL.

Volumetric CT with sparse detector arrays (and application to Si-strip photon counters).

Science.gov (United States)

Sisniega, A; Zbijewski, W; Stayman, J W; Xu, J; Taguchi, K; Fredenberg, E; Lundqvist, Mats; Siewerdsen, J H

2016-01-07

Novel x-ray medical imaging sensors, such as photon counting detectors (PCDs) and large area CCD and CMOS cameras can involve irregular and/or sparse sampling of the detector plane. Application of such detectors to CT involves undersampling that is markedly different from the commonly considered case of sparse angular sampling. This work investigates volumetric sampling in CT systems incorporating sparsely sampled detectors with axial and helical scan orbits and evaluates performance of model-based image reconstruction (MBIR) with spatially varying regularization in mitigating artifacts due to sparse detector sampling. Volumetric metrics of sampling density and uniformity were introduced. Penalized-likelihood MBIR with a spatially varying penalty that homogenized resolution by accounting for variations in local sampling density (i.e. detector gaps) was evaluated. The proposed methodology was tested in simulations and on an imaging bench based on a Si-strip PCD (total area 5 cm  ×  25 cm) consisting of an arrangement of line sensors separated by gaps of up to 2.5 mm. The bench was equipped with translation/rotation stages allowing a variety of scanning trajectories, ranging from a simple axial acquisition to helical scans with variable pitch. Statistical (spherical clutter) and anthropomorphic (hand) phantoms were considered. Image quality was compared to that obtained with a conventional uniform penalty in terms of structural similarity index (SSIM), image uniformity, spatial resolution, contrast, and noise. Scan trajectories with intermediate helical width (~10 mm longitudinal distance per 360° rotation) demonstrated optimal tradeoff between the average sampling density and the homogeneity of sampling throughout the volume. For a scan trajectory with 10.8 mm helical width, the spatially varying penalty resulted in significant visual reduction of sampling artifacts, confirmed by a 10% reduction in minimum SSIM (from 0.88 to 0.8) and a 40

A New Virtual Point Detector Concept for a HPGe detector

International Nuclear Information System (INIS)

Byun, Jong In; Yun, Ju Yong

2009-01-01

For last several decades, the radiation measurement and radioactivity analysis techniques using gamma detectors have been well established. Especially , the study about the detection efficiency has been done as an important part of gamma spectrometry. The detection efficiency depends strongly on source-to-detector distance. The detection efficiency with source-to-detector distance can be expressed by a complex function of geometry and physical characteristics of gamma detectors. In order to simplify the relation, a virtual point detector concept was introduced by Notea. Recently, further studies concerning the virtual point detector have been performed. In previous other works the virtual point detector has been considered as a fictitious point existing behind the detector end cap. However the virtual point detector position for the front and side of voluminous detectors might be different due to different effective central axis of them. In order to more accurately define the relation, therefore, we should consider the virtual point detector for the front as well as side and off-center of the detector. The aim of this study is to accurately define the relation between the detection efficiency and source-to-detector distance with the virtual point detector. This paper demonstrates the method to situate the virtual point detectors for a HPGe detector. The new virtual point detector concept was introduced for three area of the detector and its characteristics also were demonstrated by using Monte Carlo Simulation method. We found that the detector has three virtual point detectors except for its rear area. This shows that we should consider the virtual point detectors for each area when applying the concept to radiation measurement. This concept can be applied to the accurate geometric simplification for the detector and radioactive sources.

A beam-synchronous gated peak-detector for the LHC beam observation system

CERN Document Server

Levens, T E; Wehrle, U

2013-01-01

Measurements of the bunch peak amplitude using the longitudinal wideband wall-current monitor are a vital tool used in the Large Hadron Collider (LHC) beam observation system. These peak-detected measurements can be used to diagnose bunch shape oscillations, for example coherent quadrupole oscillations, that occur at injection and during beam manipulations. Peak-detected Schottky diagnostics can also be used to obtain the synchrotron frequency distribution and other parameters from a bunched beam under stable conditions. For the LHC a beam-synchronous gated peak detector has been developed to allow individual bunches to be monitored without the influence of other bunches circulating in the machine. The requirement for the observation of both low intensity pilot bunches and high intensity bunches for physics requires a detector front-end with a high bandwidth and a large dynamic range while the usage for Schottky measurements requires low noise electronics. This paper will present the design of this detector s...

Application of the pulse-shape technique to proton-alpha discrimination in Si-detector arrays

International Nuclear Information System (INIS)

Pausch, G.; Moszynski, M.; Wolski, D.; Bohne, W.; Grawe, H.; Hilscher, D.; Schubart, R.; De Angelis, G.; De Poli, M.

1995-04-01

The capability of the pulse-shape technique with reversed n-type Si detectors for discrimination of protons and alphas produced in fusion-evaporation reactions was tested at the VICKSI cyclotron in Berlin. We applied a zero-crossing technique which does not need any external time reference, and which can therefore be exploited at DC accelerators. Excellent proton-alpha discrimination in the full energy range of the evaporation spectra, but also charge and even isotope resolution for heavier ions produced in projectile fragmentation, was obtained with detectors of an existing Si ball. There is no doubt that the pulse-shape discrimination works well with detectors from serial production and under experimental conditions which are typical for nuclear structure studies. An application of this technique in Si detector arrays is obvious, but some special features must be considered in the design of the electronics. The particle discrimination depends strongly on the electric field distribution inside the detector. Stabilization of the bias voltage at the detector is therefore recommended. A consequence of the rear-side injection mode is a strong variation of the charge-collection time with energy, charge, and mass number of the detected ion. To obtain a precise energy signal it is indispensable to correct for the ballistic deficit. (orig.)

Pulser injection with subsequent removal for gamma-ray spectrometry

International Nuclear Information System (INIS)

Hartwell, J.K.; Goodwin, S.G.; Johnson, L.O.; Killian, E.W.

1990-01-01

This patent describes a module for use with a gamma-ray spectroscopy system. The system includes a gamma-ray detector for detecting gamma-ray events and producing a signal representing the gamma-ray events, a converter responsive to the detector and capable of converting the signal to a spectrum, a storage memory responsive to the converter and capable of storing the spectrum at address locations in memory, and a pulser capable of injecting pulses into the signal produced by the detector. The module comprises: means for generating a logic pulse for controlling the pulser, the controlling means adapted for coupling to the pulser; means for generating separation of events logic to isolate the components of a combined gamma-ray---pulse spectrum, the separation of events logic means adapted for coupling to the converter and the storage memory with the capability of storing pulses at address locations in the storage memory separate from the gamma-ray events; means for receiving an imitating signal from the converter to generate a plurality of operations by the module; means for tracking variations in a gamma-ray---pulse spectrum brought on by external parameter changes; and means for interfacing with commercially developed gamma-ray spectrometry equipment

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.

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.

Multicommuted flow injection method for fast photometric determination of phenolic compounds in commercial virgin olive oil samples.

Science.gov (United States)

Lara-Ortega, Felipe J; Sainz-Gonzalo, Francisco J; Gilbert-López, Bienvenida; García-Reyes, Juan F; Molina-Díaz, Antonio

2016-01-15

A multicommuted flow injection method has been developed for the determination of phenolic species in virgin olive oil samples. The method is based on the inhibitory effect of antioxidants on a stable and colored radical cation formation from the colorless compound N,N-dimethyl-p-phenylenediamine (DMPD(•+)) in acidic medium in the presence of Fe(III) as oxidant. The signal inhibition by phenolic species and other antioxidants is proportional to their concentration in the olive oil sample. Absorbance was recorded at 515nm by means of a modular fiber optic spectrometer. Oleuropein was used as the standard for phenols determination and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox) was the reference standard used for total antioxidant content calculation. Linear response was observed within the range of 250-1000mg/kg oleuropein, which was in accordance with phenolic contents observed in commercial extra virgin olive oil in the present study. Fast and low-volume liquid-liquid extraction of the samples using 60% MeOH was made previous to their insertion in the flow multicommuted system. The five three-way solenoid valves used for multicommuted liquid handling were controlled by a homemade electronic interface and Java-written software. The proposed approach was applied to different commercial extra virgin olive oil samples and the results were consistent with those obtained by the Folin Ciocalteu (FC) method. Total time for the sample preparation and the analysis required in the present approach can be drastically reduced: the throughput of the present analysis is 8 samples/h in contrast to 1sample/h of the conventional FC method. The present method is easy to implement in routine analysis and can be regarded as a feasible alternative to FC method. Copyright © 2015 Elsevier B.V. All rights reserved.

Design, calibration, and performance of the MINERvA detector

Energy Technology Data Exchange (ETDEWEB)

Aliaga, L. [Department of Physics, College of William and Mary, Williamsburg, VA 23187 (United States); Sección Física, Departamento de Ciencias, Pontificia Universidad Católica del Perú, Apartado 1761, Lima, Perú (Peru); Bagby, L.; Baldin, B. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Baumbaugh, A. [Sección Física, Departamento de Ciencias, Pontificia Universidad Católica del Perú, Apartado 1761, Lima, Perú (Peru); Bodek, A.; Bradford, R. [University of Rochester, Rochester, NY 14610 (United States); Brooks, W.K. [Departamento de Física, Universidad Técnica Federico Santa María, Avda. España 1680, Casilla 110-V, Valparaíso (Chile); Boehnlein, D. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Boyd, S. [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Budd, H. [University of Rochester, Rochester, NY 14610 (United States); Butkevich, A. [Institute for Nuclear Research of the Russian Academy of Sciences, 117312 Moscow (Russian Federation); Martinez Caicedo, D.A.; Castromonte, C.M. [Hampton University, Department of Physics, Hampton, VA 23668 (United States); Christy, M.E. [Department of Physics, University of Minnesota – Duluth, Duluth, MN 55812 (United States); Chvojka, J. [University of Rochester, Rochester, NY 14610 (United States); Motta, H. da [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Urca, Rio de Janeiro, RJ 22290-180 (Brazil); and others

2014-04-11

The MINERvA experiment is designed to perform precision studies of neutrino-nucleus scattering using ν{sub μ} and ν{sup ¯}{sub μ} neutrinos incident at 1–20 GeV in the NuMI beam at Fermilab. This article presents a detailed description of the MINERvA detector and describes the ex situ and in situ techniques employed to characterize the detector and monitor its performance. The detector is composed of a finely segmented scintillator-based inner tracking region surrounded by electromagnetic and hadronic sampling calorimetry. The upstream portion of the detector includes planes of graphite, iron and lead interleaved between tracking planes to facilitate the study of nuclear effects in neutrino interactions. Observations concerning the detector response over sustained periods of running are reported. The detector design and methods of operation have relevance to future neutrino experiments in which segmented scintillator tracking is utilized.

Spin injection into GaAs

Energy Technology Data Exchange (ETDEWEB)

Endres, Bernhard

2013-11-01

In this work spin injection into GaAs from Fe and (Ga,Mn)As was investigated. For the realization of any spintronic device the detailed knowledge about the spin lifetime, the spatial distribution of spin-polarized carriers and the influence of electric fields is essential. In the present work all these aspects have been analyzed by optical measurements of the polar magneto-optic Kerr effect (pMOKE) at the cleaved edge of the samples. Besides the attempt to observe spin pumping and thermal spin injection into n-GaAs the spin solar cell effect is demonstrated, a novel mechanism for the optical generation of spins in semiconductors with potential for future spintronic applications. Also important for spin-based devices as transistors is the presented realization of electrical spin injection into a two-dimensional electron gas.

Cross-border drug injection relationships among injection drug users in Tijuana, Mexico

Science.gov (United States)

Wagner, Karla D.; Pollini, Robin A.; Patterson, Thomas L.; Lozada, Remedios; Ojeda, Victoria D.; Brouwer, Kimberly C.; Vera, Alicia; Volkmann, Tyson A.; Strathdee, Steffanie A.

2010-01-01

Background International borders are unique social and environmental contexts characterized by high levels of mobility. Among drug users, mobility increases risk for human immunodeficiency virus (HIV) in part through its effects on the social environment. However, the social dynamics of drug users living in border regions are understudied. Methods 1056 injection drug users (IDUs) residing in Tijuana, Mexico were recruited using respondent-driven sampling (RDS) from 2006 to 2007, and underwent surveys and testing for HIV, syphilis, and tuberculosis (TB). Using logistic regression on baseline data, we identified correlates of having ever injected drugs with someone from the US. Results Almost half (48%) reported ever injecting drugs with someone from the US. In RDS-adjusted logistic regression, factors independently associated with having ever injected with someone from the US included: having greater than middle school education (Adjusted Odds Ratio [AOR] 2.91; 95% Confidence Interval [C.I.] 1.52, 5.91), speaking English (AOR 3.24, 95% C.I. 1.96, 5.36), age (AOR 1.10 per year; 95% C.I. 1.07, 1.14), age at initiation of injection drug use (AOR 0.90 per year; 95% C.I. 0.86, 0.94), homelessness (AOR 2.61; 95% C.I. 1.27, 5.39), and having ever been incarcerated (AOR 11.82; 95% C.I., 5.22, 26.77). No associations with HIV, syphilis, TB, drug use, or injection risk behavior were detected. Conclusion Findings suggest that IDU networks in Mexico and the US may transcend international borders, with implications for cross-border transmission of infectious disease. Binational programs and policies need to consider the structure and geographic distribution of drug using networks. PMID:20889270

Detector Control System for the ATLAS Forward Proton detector

CERN Document Server

Czekierda, Sabina; The ATLAS collaboration

2017-01-01

The ATLAS Forward Proton (AFP) is a forward detector using a Roman Pot technique, recently installed in the LHC tunnel. It is aiming at registering protons that were diffractively or electromagnetically scattered in soft and hard processes. Infrastructure of the detector consists of hardware placed both in the tunnel and in the control room USA15 (about 330 meters from the Roman Pots). AFP detector, like the other detectors of the ATLAS experiment, uses the Detector Control System (DCS) to supervise the detector and to ensure its safe and coherent operation, since the incorrect detector performance may influence the physics results. The DCS continuously monitors the detector parameters, subset of which is stored in data bases. Crucial parameters are guarded by alarm system. A detector representation as a hierarchical tree-like structure of well-defined subsystems built with the use of the Finite State Machine (FSM) toolkit allows for overall detector operation and visualization. Every node in the hierarchy is...

The Karlsruhe 4π barium fluoride detector

International Nuclear Information System (INIS)

Wisshak, K.; Guber, K.; Kaeppeler, F.; Krisch, J.; Mueller, H.; Rupp, G.; Voss, F.

1989-12-01

A new experimental approach has been implemented for accurate measurements of neutron capture cross sections in the energy range from 5 to 200 keV. The Karlsruhe 4π Barium Fluoride Detector consists of 42 crystals shaped as hexagonal and pentagonal truncated pyramids forming a spherical shell with 10 cm inner radius and 15 cm thickness. All crystals are supplied with reflector and photomultiplier, thus representing independent gamma-ray detectors. Each detector module covers the same solid angle with respect to a gamma-ray source located in the centre. The energy resolution of the 4π detector is 14% at 662 keV and 7% at 2.5 MeV gamma-ray energy, the overall time reslution is 500 ps and the peak efficiency 90% at 1 MeV. The detector allows to register capture cascades with 95% probability above a threshold energy of 2.5 MeV in the sum energy spectrum. Neutrons are produced via the 7 Li(p,n) 7 Be reaction using the pulsed proton beam of a Van de Graaff accelerator. The neutron spectrum can be taylored according to the experimental requirements in an energy range from 5 to 200 keV by choosing appropriate proton energies. A collimated neutron beam is passing through the detector and hits the sample in the centre. The energy of captured neutrons is determined via time of flight, the primary flight path being 77 cm. The combination of short primary flight path, a 10 cm inner radius of the spherical BaF 2 shell, and the low capture cross section of barium allows to discriminate background due to capture of sample scattered neutrons in the scintillator by time of flight, leaving part of the neutron energy range completely undisturbed. (orig./HSI) [de

Injecting drug use: Gendered risk.

Science.gov (United States)

Zahnow, Renee; Winstock, Adam R; Maier, Larissa J; Levy, Jay; Ferris, Jason

2018-06-01

Research demonstrates gender related differences in drug-use practices and risk behaviours. Females' structural vulnerability stemming from traditional gender roles and gender-power relations may enhance their propensity to experience injecting related risk. In this paper we explore gender differences in injection practices at the initiation event, during the first year of injecting and in the most recent 12-month period, to inform more effective harm reduction strategies. Data used in this study were drawn from the Global Drug Survey 2015. The study employs chi-square and logistic regression to assess gender differences in injection behaviours in a sample of current injectors residing in six global regions: North-West Europe; Southern Eastern Europe; North America. South America and Oceania. Females were more likely than males to report being injected by an intimate partner at initiation (OR = 4.4, 95%CI: 2.2-8.8), during the first year of injecting (OR = 4.8, 95% CI: 2.4-9.3) and in the most recent 12-month period (OR = 2.5, 95%CI: 1.0-6.2). Females reported greater difficulties accessing sterile equipment (X 2 (2,N = 453) = 8.2, p = 0.02) and were more likely to share injecting equipment than males (X 2 (1,N = 463) = 3.9, p = 0.05). Our findings highlight females' continued dependence on their intimate partner to administer the injection into the first year of their injecting career. Females remained more likely than males to rely on intimate partners for injection during the most recent 12-month period. Females report greater difficulties in sourcing sterile equipment and are more likely to share injecting equipment. We suggest that these findings reflect the broader social structure in which females are disempowered through traditional gender roles and the lack of gender appropriate harm reduction services. Copyright © 2018 Elsevier B.V. All rights reserved.

Gas chromatography-flame ionization determination of benzaldehyde in non-steroidal anti-inflammatory drug injectable formulations using new ultrasound-assisted dispersive liquid-liquid micro extraction

International Nuclear Information System (INIS)

Mashayekhi, H.A.; Pourshamsian, K.

2012-01-01

Summary: In this study, simple and efficient ultrasound-assisted dispersive liquid-liquid micro extraction combined with gas chromatography (GC) was developed for the preconcentration and determination of benzaldehyde in injectable formulations of the non-steroidal anti-inflammatory drugs, diclofenac, Vitamin B-complex and Voltaren injection solutions. Fourteen microliters of toluene was injected slowly into 10 mL home-designed centrifuge glass vial containing an aqueous sample without salt addition that was located inside the ultrasonic water bath. The formed emulsion was centrifuged and 2 macro L of separated toluene was injected into a gas chromatographic system equipped with a flame ionization detector (GC-FID) for analysis. Several factors influencing the extraction efficiency as the nature and volume of organic solvent, extraction temperature, ionic strength and centrifugation time were investigated and optimized. Using optimum extraction conditions a detection limit of 0.3 macro g L/sup -1/ and a good linearity in a calibration range of 2.0-1000 macro g L/sup -1/ were achieved for analyte. This proposed method was successfully applied to the analysis of benzaldehyde in three injection formulations and relative standard deviation (RSD) of analysis (n=3), before spiking with standard benzaldehyde were 3.3, 2.0 and 1.3% for Na-diclofenac, vitamin B-complex and voltaren, respectively and after spiking of standard benzaldehyde (0.3 mg L/sup -1/), the RSD were 6.5, 3.6 and 2.8% for Na-diclofenac, vitamin B-complex and voltaren, respectively. (author)

Chemical analysis: modern instrumentation methods and techniques

National Research Council Canada - National Science Library

Rouessac, Francis; Rouessac, Annick

2007-01-01

... regulation 2.3 Sample introduction and the injection chamber 2.4 Thermostatically controlled oven 2.5 Columns 2.6 Stationary phases 2.7 Principal gas chromatographic detectors 2.8 Detectors provi...

Hyaluronic Acid Injections for Treatment of Advanced Osteoarthritis of the Knee: Utilization and Cost in a National Population Sample.

Science.gov (United States)

Weick, Jack W; Bawa, Harpreet S; Dirschl, Douglas R

2016-09-07

The prevalence of knee osteoarthritis is increasing in the aging U.S. The efficacy and cost-effectiveness of the use of hyaluronic acid (HA) injections for the treatment of knee osteoarthritis are debated. In this study, we assessed the utilization and costs of HA injections in the 12 months preceding total knee arthroplasty (TKA) and evaluated the usage of HA injections in end-stage knee osteoarthritis management in relation to other treatments. MarketScan Commercial Claims and Encounters and Medicare Supplemental and Coordination of Benefits databases (Truven Health Analytics) were reviewed to identify patients who underwent TKA from 2005 to 2012. The utilization of patient-specific osteoarthritis-related health care (including medications, corticosteroid injections, HA injections, imaging, and office visits) and payment information were analyzed for the 12 months preceding TKA. A total of 244,059 patients met the inclusion criteria. Of those, 35,935 (14.7%) had ≥1 HA injection in the 12 months preceding TKA. HA injections were responsible for 16.4% of all knee osteoarthritis-related payments, trailing only imaging studies (18.2%), and HA injections accounted for 25.2% of treatment-specific payments, a rate that was higher than that of any other treatment. Patients receiving HA injections were significantly more likely to receive additional knee osteoarthritis-related treatments compared with patients who did not receive HA injections. Despite numerous studies questioning the efficacy and cost-effectiveness of HA injections for osteoarthritis of the knee, HA injections are still utilized for a substantial percentage of patients. Given the paucity of data supporting the effectiveness of HA injections and the current cost-conscious health-care climate, decreasing their use among patients with end-stage knee osteoarthritis may represent a substantial cost reduction that likely does not adversely impact the quality of care. Copyright © 2016 by The Journal of Bone

Quality control of a detector for the calculations of radiopharmacokinetic parameters of 99mTc-glucarate in rats

International Nuclear Information System (INIS)

Molina-Trinidad, E.M.; Arteaga de Murphy, C.; Jung-Cook, H.

2004-01-01

Good manufacturing practices specify that a well-type scintillation NaI(Tl) crystal detector has to be validated in order to detect radioactivity from any radiopharmaceutical used to obtain radiopharmacokinetic parameters. A 5 cm well-type NaI(Tl) scintillation detector was coupled to a multi-channel analyzer centered at the 140 keV 99m Tc peak with a 20% window. The area represents counts per minute (cpm). All the net cpm were decay corrected. The activity source was 99m Tc-glucarate developed as an imaging agent for acute myocardial infarction. Wistar rats were injected in a tail vein with 0.1 ml (3.7 MBq) of 99m Tc-glucarate solution and 13 blood samples were taken. The cpm were the input data for the WINNONLN program which calculates radiopharmacokinetic parameters. The detector's efficiency for 99m Tc was 15.03% and the sensitivity 1.12 kBq/ml in plasma. The response was linear between 0.31-14.3 kBq/ml of 99m Tc-glucarate. The maximum assay variation coefficient was 2.79 and recovery of 99m Tc-glucarate in plasma was 99.8% ± 0.2%. LOD was 0.31 kBq and LOQ 1.12 kBq in plasma samples. 99m Tc-glucarate follows a two-compartment model of distribution with Vd of 21.74 ml ± 2.71 ml; a Vdss of 74.36 ml ± 12.67 ml; t 1/2α 0.74 h ± 0.19 h; t 1/2β 18.98 h ± 4.36 h; AUC = 32.75 μCi/min x ml ± 3.73 μCi/min x ml; MRT 24.35 h ± 5.51 h and total clearance 3.05 ml/h ±0.35 ml/h. The well-type detector fulfills the quality system requirements and the radiopharmacokinetic parameters for 99m Tc-glucarate in rats are reliable. (author)

Program LEP to addition of gamma spectra from germanium detectors; Programa LEPS para suma de espectros gammas de detectores de germanio

Energy Technology Data Exchange (ETDEWEB)

Romero, L

1986-07-01

The LEP program, written in FORTRAN IV, performs the addition of two spectra, collected with different detectors, from the same sample. This application, adds the two gamma spectra obtained from two opposite LEPS Germanium Detectors (Low Energy Photon Spectrometer), correcting the differences (channel/energy) between both two spectra, and fitting them before adding. The total-spectrum is recorded at the computer memory as a single spectrum. The necessary equipment, to run this program is: - Two opposite germanium detectors, with their associate electronics. - Multichannel analyzer (2048 memory channel minimum) - Computer on-line interfacing to multichannel analyzer. (Author) 4 refs.

Rapid determination of piracetam in human plasma and cerebrospinal fluid by micellar electrokinetic chromatography with sample direct injection.

Science.gov (United States)

Yeh, Hsin-Hua; Yang, Yuan-Han; Ko, Ju-Yun; Chen, Su-Hwei

2006-07-07

A simple micellar electrokinetic chromatography (MEKC) method with UV detection at 200 nm for analysis of piracetam in plasma and in cerebrospinal fluid (CSF) by direct injection without any sample pretreatment is described. The separation of piracetam from biological matrix was performed at 25 degrees C using a background electrolyte consisting of Tris buffer with sodium dodecyl sulfate (SDS) as the electrolyte solution. Several parameters affecting the separation of the drug from biological matrix were studied, including the pH and concentrations of the Tris buffer and SDS. Under optimal MEKC condition, good separation with high efficiency and short analyses time is achieved. Using imidazole as an internal standard (IS), the linear ranges of the method for the determination of piracetam in plasma and in CSF were all between 5 and 500 microg/mL; the detection limit of the drug in plasma and in CSF (signal-to-noise ratio=3; injection 0.5 psi, 5s) was 1.0 microg/mL. The applicability of the proposed method for determination of piracetam in plasma and CSF collected after intravenous administration of 3g piracetam every 6h and oral administration 1.2g every 6h in encephalopathy patients with aphasia was demonstrated.

The effect of solarradiation and UV photons on the CR-39 nuclear track detector

International Nuclear Information System (INIS)

Saad, A.F.

2003-01-01

The effects induced in the CR-39 polymer detector by total solar radiation (TSR) and UV photons were investigated. Thr exposure of detector samples to solar photons was carried out according to certain conditions. The TSR exposure period started in the middle of july and lasted unitel 12 th of september. 2000: the hottest months in zagazig, egypt. Another set of detector samples was exposed to UV photons from a UV lamp for different intervals. After UV exposure, these detectors were analysed with an FT-IR sepectrometer of jasco type 5300 in transmission mode. The FT-IR spectra does not show any considerable modifications due to UV irradiation in that detector. The effects of UV light were compared with those of solar radiation containing ultraviolet photons , on the registration properties of this polymer detector. Preliminaryresults revealed a proportionate increase in bluk etch rate of CR-39 detector with the increase of exposure time to the solar radiation. The results indicated that the CR-39 polymer detector can be used as a solar radiation dosimeter

The measurement of radioactive microspheres in biological samples

International Nuclear Information System (INIS)

Mernagh, J.R.; Spiers, E.W.; Adiseshiah, M.

1976-01-01

Measurements of the distribution of radioactive microspheres are used in investigations of regional coronary blood flow, but the size and shape of the heart varies for different test animals, and the organ is frequently divided into smaller pieces for studies of regional perfusion. Errors are introduced by variations in the distribution of the radioactive source and the amount of Compton scatter in different samples. A technique has therefore been developed to allow the counting of these tissue samples in their original form, and correction factors have been derived to inter-relate the various counting geometries thus encountered. Dogs were injected with microspheres labelled with 141 Ce, 51 Cr or 85 Sr. The tissue samples did not require remodelling to fit a standard container, and allowance was made for the inhomogeneous distribution in the blood samples. The activities in the centrifuged blood samples were correlated with those from the tissue samples by a calibration procedure involving comparisons of the counts from samples of microspheres embedded in sachets of gelatine, and similar samples mixed with blood and then centrifuged. The calibration data have indicated that 51 Cr behaves anomalously, and its use as a label for microspheres may introduce unwarranted errors. A plane cylindrical 10 x 20 cm NaI detector was used, and a 'worst case' correction of 20% was found to be necessary for geometry effects. The accuracy of this method of correlating different geometries was tested by remodelling the same tissue sample into different sizes and comparing the results, and the validity of the technique was supported by agreement of the final results with previously published data. (U.K.)

Detector calibration for in-situ gamma ray spectrometry

CERN Document Server

Balea, G

2002-01-01

The power in the technique of in-situ spectrometry lies in the fact that a detector placed on ground measures gamma radiation from sources situated over an area of several hundred square meters. The 'field of view' for the detector would be larger for high energy radiation sources and for sources closer to the soil surface. In contrast, a soil sample would represent an area of a few tens of hundreds of square centimeters. In practice, an effective characterization of a site would involve in-situ gamma ray spectrometry in conjunction with soil sampling. As part of an overall program, in-situ gamma ray spectrometry provides a means to assess the degree of contamination in areas during the course of operations in the field, thus guiding the investigator on where to collect samples. It can also substantially reduce the number of samples need to be collected and subsequently analyzed. (author)

Liquid chromatography detection unit, system, and method

Science.gov (United States)

Derenzo, Stephen E.; Moses, William W.

2015-10-27

An embodiment of a liquid chromatography detection unit includes a fluid channel and a radiation detector. The radiation detector is operable to image a distribution of a radiolabeled compound as the distribution travels along the fluid channel. An embodiment of a liquid chromatography system includes an injector, a separation column, and a radiation detector. The injector is operable to inject a sample that includes a radiolabeled compound into a solvent stream. The position sensitive radiation detector is operable to image a distribution of the radiolabeled compound as the distribution travels along a fluid channel. An embodiment of a method of liquid chromatography includes injecting a sample that comprises radiolabeled compounds into a solvent. The radiolabeled compounds are then separated. A position sensitive radiation detector is employed to image distributions of the radiolabeled compounds as the radiolabeled compounds travel along a fluid channel.

Injection and Non-Injection Drug Use and Infectious Disease in Baltimore City: Differences by Race

Science.gov (United States)

Keen, Larry; Khan, Maria; Clifford, Lisa; Harrell, Paul T.; Latimer, William W.

2014-01-01

Purpose The current study examines differences in the prevalence of biologically-confirmed hepatitis C virus (HCV), HIV, and coinfection between Black and White adult cocaine/heroin users across three drug use subgroups identified in previous research (Harrell et al, 2012): non-injection smoking crack/nasal heroin users, heroin injectors, and polydrug injectors. Results 59% of the 482 participants in the study were male. Significant race differences emerged between drug use subgroup memberships. Non-injection smoking crack/nasal heroin users were predominantly Black (75%), while heroin injectors and polydrug injectors were predominantly White (69% and 72%, respectively). Polydrug injectors accounted for nearly three quarters of the HCV positive diagnoses in Whites. Though HIV disease status, stratified by race, did not differ significantly between drug use subgroups, the non-injection smoking crack/nasal heroin subgroup contained over half of the HIV positive diagnoses in the sample and was predominantly Black. Despite much lower rates of injection, Blacks (8%) had a higher prevalence of coinfection than Whites (3%; X2 (2) = 6.18, p = .015). Conclusions The current findings are consistent with trends in recent HIV transmission statistics where sexual activity has overtaken injection drug use as a HIV risk factor. The current findings also provide further support to the notion of injection drug use as an exceedingly high-risk behavior for HCV and coinfection, specifically those who are polysubstance injectors. PMID:24837755

Calibration of detector efficiency of neutron detector

International Nuclear Information System (INIS)

Guo Hongsheng; He Xijun; Xu Rongkun; Peng Taiping

2001-01-01

BF 3 neutron detector has been set up. Detector efficiency is calibrated by associated particle technique. It is about 3.17 x 10 -4 (1 +- 18%). Neutron yield of neutron generator per pulse (10 7 /pulse) is measured by using the detector

Texture analysis with neutron bending on geological/mineralogical multi-phase samples using a locally resolving detector and profile analysis

International Nuclear Information System (INIS)

Merz, P.L.

1991-02-01

In the context of this work, the NANCY four circuit diffractometer of the University of Bonn at the RRJ2 research reactor at KFA Juelich was equipped with a linear locally resolving scintillation detector JULIOS. To evaluate the diffractogram occurring at a pole figure measurement, user-friendly profile analysis and other evaluation programs were developed on the PC. The course of evaluation was largely automated, so that only a few interactive steps are required. The measuring period of a sample is usually two to three days. Up to 35 pole figures are produced, depending on the phase conditions of the examined sample. The evaluation of up to 900 diffractograms with the aid of the automatically running profile analysis program takes between 30 and 100 minutes on a 20 MHz PC 386. Pole figure datafiles are produced from the intensity data obtained in this way by a conversion program. The texture analyses of copper pyrites ores introduced here are connected with geological questions. (orig.) [de

MINERvA neutrino detector response measured with test beam data

International Nuclear Information System (INIS)

Aliaga, L.; Altinok, O.; Araujo Del Castillo, C.; Bagby, L.; Bellantoni, L.; Bergan, W.F.; Bodek, A.; Bradford, R.; Bravar, A.; Budd, H.; Butkevich, A.; Martinez Caicedo, D.A.; Carneiro, M.F.; Christy, M.E.; Chvojka, J.; Motta, H. da; Devan, J.

2015-01-01

The MINERvA collaboration operated a scaled-down replica of thesolid scintillator tracking and sampling calorimeter regions of the MINERvA detector in a hadron test beam at the Fermilab Test Beam Facility. This paper reports measurements with samples of protons, pions, and electrons from 0.35 to 2.0 GeV/c momentum. The calorimetric response to protons, pions, and electrons is obtained from these data. A measurement of the parameter in Birks' law and an estimate of the tracking efficiency are extracted from the proton sample. Overall the data are well described by a Geant4-based Monte Carlo simulation of the detector and particle interactions with agreements better than 4% for the calorimetric response, though some features of the data are not precisely modeled. These measurements are used to tune the MINERvA detector simulation and evaluate systematic uncertainties in support of the MINERvA neutrino cross-section measurement program

MINERvA neutrino detector response measured with test beam data

Energy Technology Data Exchange (ETDEWEB)

Aliaga, L. [Department of Physics, College of William & Mary, Williamsburg, VA 23187 (United States); Altinok, O. [Physics Department, Tufts University, Medford, MA 02155 (United States); Araujo Del Castillo, C. [Sección Física, Departamento de Ciencias, Pontificia Universidad Católica del Perú, Apartado 1761, Lima (Peru); Bagby, L.; Bellantoni, L. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Bergan, W.F. [Department of Physics, College of William & Mary, Williamsburg, VA 23187 (United States); Bodek, A.; Bradford, R. [University of Rochester, Rochester, New York 14627 (United States); Bravar, A. [University of Geneva, 1211 Geneva 4 (Switzerland); Budd, H. [University of Rochester, Rochester, New York 14627 (United States); Butkevich, A. [Institute for Nuclear Research of the Russian Academy of Sciences, 117312 Moscow (Russian Federation); Martinez Caicedo, D.A. [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Urca, Rio de Janeiro, Rio de Janeiro 22290-180 (Brazil); Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Carneiro, M.F. [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Urca, Rio de Janeiro, Rio de Janeiro 22290-180 (Brazil); Christy, M.E. [Hampton University, Department of Physics, Hampton, VA 23668 (United States); Chvojka, J. [University of Rochester, Rochester, New York 14627 (United States); Motta, H. da [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Urca, Rio de Janeiro, Rio de Janeiro 22290-180 (Brazil); Devan, J. [Department of Physics, College of William & Mary, Williamsburg, VA 23187 (United States); and others

2015-07-21

The MINERvA collaboration operated a scaled-down replica of thesolid scintillator tracking and sampling calorimeter regions of the MINERvA detector in a hadron test beam at the Fermilab Test Beam Facility. This paper reports measurements with samples of protons, pions, and electrons from 0.35 to 2.0 GeV/c momentum. The calorimetric response to protons, pions, and electrons is obtained from these data. A measurement of the parameter in Birks' law and an estimate of the tracking efficiency are extracted from the proton sample. Overall the data are well described by a Geant4-based Monte Carlo simulation of the detector and particle interactions with agreements better than 4% for the calorimetric response, though some features of the data are not precisely modeled. These measurements are used to tune the MINERvA detector simulation and evaluate systematic uncertainties in support of the MINERvA neutrino cross-section measurement program.

Optical re-injection in cavity-enhanced absorption spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Leen, J. Brian, E-mail: b.leen@lgrinc.com; O’Keefe, Anthony [Los Gatos Research, 67 E. Evelyn Avenue, Suite 3, Mountain View, California 94041 (United States)

2014-09-15

Non-mode-matched cavity-enhanced absorption spectrometry (e.g., cavity ringdown spectroscopy and integrated cavity output spectroscopy) is commonly used for the ultrasensitive detection of trace gases. These techniques are attractive for their simplicity and robustness, but their performance may be limited by the reflection of light from the front mirror and the resulting low optical transmission. Although this low transmitted power can sometimes be overcome with higher power lasers and lower noise detectors (e.g., in the near-infrared), many regimes exist where the available light intensity or photodetector sensitivity limits instrument performance (e.g., in the mid-infrared). In this article, we describe a method of repeatedly re-injecting light reflected off the front mirror of the optical cavity to boost the cavity's circulating power and deliver more light to the photodetector and thus increase the signal-to-noise ratio of the absorption measurement. We model and experimentally demonstrate the method's performance using off-axis cavity ringdown spectroscopy (OA-CRDS) with a broadly tunable external cavity quantum cascade laser. The power coupled through the cavity to the detector is increased by a factor of 22.5. The cavity loss is measured with a precision of 2 × 10{sup −10} cm{sup −1}/√(Hz;) an increase of 12 times over the standard off-axis configuration without reinjection and comparable to the best reported sensitivities in the mid-infrared. Finally, the re-injected CRDS system is used to measure the spectrum of several volatile organic compounds, demonstrating the improved ability to resolve weakly absorbing spectroscopic features.

Superconducting Kinetic Inductance Detectors for astronomy and particle physics

International Nuclear Information System (INIS)

Calvo, M.; Goupy, J.; D'Addabbo, A.; Benoit, A.; Bourrion, O.; Catalano, A.; Monfardini, A.

2016-01-01

Kinetic Inductance Detectors (KID) represent a novel detector technology based on superconducting resonators. Since their first demonstration in 2003, they have been rapidly developed and are today a strong candidate for present and future experiments in the different bands of the electromagnetic spectrum. This has been possible thanks to the unique features of such devices: in particular, they couple a very high sensitivity to their intrinsic suitability for frequency domain multiplexed readout, making the fabrication of large arrays of ultrasensitive detectors possible. There are many fields of application that can profit of such detectors. Here, we will briefly review the principle of operation of a KID, and give two sample applications, to mm-wave astronomy and to particle physics.

Superconducting Kinetic Inductance Detectors for astronomy and particle physics

Energy Technology Data Exchange (ETDEWEB)

Calvo, M., E-mail: martino.calvo@neel.cnrs.fr [Institute Néel, CNRS, Grenoble (France); Goupy, J.; D' Addabbo, A.; Benoit, A. [Institute Néel, CNRS, Grenoble (France); Bourrion, O. [Laboratoire de Physique Subatomique et Cosmologie, CNRS, Grenoble (France); Catalano, A. [Institute Néel, CNRS, Grenoble (France); Laboratoire de Physique Subatomique et Cosmologie, CNRS, Grenoble (France); Monfardini, A. [Institute Néel, CNRS, Grenoble (France)

2016-07-11

Kinetic Inductance Detectors (KID) represent a novel detector technology based on superconducting resonators. Since their first demonstration in 2003, they have been rapidly developed and are today a strong candidate for present and future experiments in the different bands of the electromagnetic spectrum. This has been possible thanks to the unique features of such devices: in particular, they couple a very high sensitivity to their intrinsic suitability for frequency domain multiplexed readout, making the fabrication of large arrays of ultrasensitive detectors possible. There are many fields of application that can profit of such detectors. Here, we will briefly review the principle of operation of a KID, and give two sample applications, to mm-wave astronomy and to particle physics.

Coherent search of continuous gravitational wave signals: extension of the 5-vectors method to a network of detectors

International Nuclear Information System (INIS)

Astone, P; Colla, A; Frasca, S; Palomba, C; D'Antonio, S

2012-01-01

We describe the extension to multiple datasets of a coherent method for the search of continuous gravitational wave signals, based on the computation of 5-vectors. In particular, we show how to coherently combine different datasets belonging to the same detector or to different detectors. In the latter case the coherent combination is the way to have the maximum increase in signal-to-noise ratio. If the datasets belong to the same detector the advantage comes mainly from the properties of a quantity called coherence which is helpful (in both cases, in fact) in rejecting false candidates. The method has been tested searching for simulated signals injected in Gaussian noise and the results of the simulations are discussed.

Alteration of glutamate/GABA balance during acute alcohol intoxication in rats: effect of Xingnaojing injection.

Science.gov (United States)

Wei, Jingjing; Yao, Limei; Yang, Lei; Zhao, Wei; Shi, Si; Cai, Qingyan; Chen, Dingsheng; Li, Weirong; Wang, Qi

2015-05-26

Xingnaojing Injection (XNJI) is a modern Chinese formula came from famous Chinese medicine An Gong Niu Huang Pill. XNJI has been used for treatment of cerebral diseases and stroke in China, and is approved by the State Food and Drug Administration of China for the treatment of acute alcohol intoxication (AAI). XNJI belongs to the ethnopharmacological family of medicines. In this study, we investigated the mechanisms of the XNJI effect on AAI. To investigate the effects of XNJI on glutamate, gamma-aminobutyric acid (GABA) and related receptor in lateral hypothalamic area (LHA) of AAI rat. Adult male Sprague-Dawley rats were implanted with microdialysis probes in LHA. Rats were randomly divided into control, model, 1.36mg/kg XNJI, 0.68mg/kg XNJI and 0.34mg/kg XNJI groups. During microdialysis, baseline samples were collected from 1h to 2.5h; thereafter, the rats were given an intraperitoneal injection of 52% ethanol, 5.2g/kg, or saline for control group. Twenty minutes later, three doses of XNJI was given by unilateral injection respectively, while saline for control and model groups, and samples were collected for the next 4h. The extracellular glutamate and GABA levels were measured in the LHA by a high performance liquid chromatography coupled with fluorescence detector (HPLC-FLU). The expression levels of related receptors N-methyl-d-aspartate receptor (NR) subunit NR2A, NR2B and GABAA were analyzed by reverse transcription polymerase chain reaction (RT-PCR). Ethanol (5.2g/kg) significantly decreased the extracellular levels of glutamate and increased extracellular GABA in LHA. On the other hand ethanol significantly decreased NR2A and NR2B mRNAs expression, and increase GABAA mRNA expression. XNJI could increase the extracellular level of glutamate and decrease that of GABA; moreover, induced an increase in NR2A and NR2B mRNA expression, and a decrease in GABAA mRNA expression in LHA. The current changes in glutamate, GABA and mRNA expressions of related

Safe injection procedures, injection practices, and needlestick ...

African Journals Online (AJOL)

Results: Safe injection procedures regarding final waste disposal were sufficiently adopted, while measures regarding disposable injection equipment, waste containers, hand hygiene, as well as injection practices were inadequately carried out. Lack of job aid posters that promote safe injection and safe disposal of ...

Feasibility of conversion electron spectrometry using a Peltier-cooled silicon drift detector

International Nuclear Information System (INIS)

Perajarvi, K.; Turunen, J.; Ihantola, S.; Pollanen, R.; Siiskonen, T.; Toivonen, H.; Kamarainen, V.; Pomme, S.

2014-01-01

A Peltier-cooled silicon drift detector was successfully applied for conversion electron spectrometry. The energy resolution of the detector for 45 keV electrons was 0.50 keV (FWHM). The approximate thickness of the dead layer was determined to be 140 ± 20 nm Si equivalent. The relative efficiency of the detector was verified to be approximately constant in the energy range of 17-75 keV. This is concordant with the high transparency of the thin dead layer and the sufficient thickness of the detector (450 μm) to stop the electrons. The detector is suitable for use in plutonium analysis of chemically prepared samples. Moreover, it was demonstrated that conversion electron spectrometry is better than alpha spectrometry in preserving its capability to determine the 240 Pu/ 239 Pu isotopic ratio as a function of sample thickness. The investigated measurement technique can be considered a promising new tool in safeguards, complementary to existing methods. (author)

Thermally stimulated investigations on diamond X-Ray detectors

International Nuclear Information System (INIS)

Tromson, D.; Bergonzo, P.; Brambilla, A.; Mer, C.; Foulon, F.; Amosov, V.N.

1999-01-01

Intrinsic diamond material is increasingly used for the fabrication of radiation detectors. However, the presence of inherent defects has a strong impact on the detector characteristics such as the time dependent stability of the detection signal. In order to draw better insights into this effect, comparative investigations of the X-ray responses with thermally stimulated current (TSC) measurements were carried out on natural diamond detectors. TSC revealed the presence of four peaks or shoulders on natural samples in the 200 to 500 K domain. Three energy levels were identified at about 0.7, 0.71 and 0.95 eV. Time dependent X-ray detector sensitivity was investigated for various initial conditions. The results give evidence of the improvement of the detection properties after having filled traps in the material by X-ray irradiation. The comparison between the X-ray response and the TSC spectra indicate that trapping levels emptied at room temperature appear to significantly affect the performance of radiation detectors. (authors)

Multisector scintillation detector with fiber-optic light collection

Science.gov (United States)

Ampilogov, N. V.; Denisov, S. P.; Kokoulin, R. P.; Petrukhin, A. A.; Prokopenko, N. N.; Shulzhenko, I. A.; Unatlokov, I. B.; Yashin, I. I.

2017-07-01

A new type of scintillation detector for the use in high energy physics is described. The octagonal detector consists of eight triangular scintillator sectors with total area of 1 m2. Each sector represents two plates of 2 cm thick plastic scintillator. Seven 1 mm thick WLS fibers are laid evenly between the plates. The space between the fibers is filled with silicone compound to provide better light collection. Fiber ends from all eight sectors are gathered in the central part of the detector into a bunch and docked to the cathode of a FEU-115m photomultiplier. The read-out of the counter signals is carried out from 7th and 12th dynodes, providing a wide dynamic range up to about 10000 particles. The front-end electronics of the detector is based on the flash-ADC with a sampling frequency of 200 MHz. The features of detecting and recording systems of the multisector scintillation detector (MSD) and the results of its testing are discussed.

High-speed crystal detection and characterization using a fast-readout detector.

Science.gov (United States)

Aishima, Jun; Owen, Robin L; Axford, Danny; Shepherd, Emma; Winter, Graeme; Levik, Karl; Gibbons, Paul; Ashton, Alun; Evans, Gwyndaf

2010-09-01

A novel raster-scanning method combining continuous sample translation with the fast readout of a Pilatus P6M detector has been developed on microfocus beamline I24 at Diamond Light Source. This fast grid-scan tool allows the rapid evaluation of large sample volumes without the need to increase the beam size at the sample through changes in beamline hardware. A slow version is available for slow-readout detectors. Examples of grid-scan use in centring optically invisible samples and in detecting and characterizing numerous microcrystals on a mesh-like holder illustrate the most common applications of the grid scan now in routine use on I24.

Microstructural and mechanical characterization of injection molded 718 superalloy powders

Energy Technology Data Exchange (ETDEWEB)

Özgün, Özgür [Bingol University, Faculty of Engineering and Architecture, Mechanical Eng. Dep., 12000 Bingol (Turkey); Gülsoy, H. Özkan, E-mail: ogulsoy@marmara.edu.tr [Marmara University, Technology Faculty, Metallurgy and Materials Eng. Dep., 34722 Istanbul (Turkey); Yılmaz, Ramazan [Sakarya University, Technology Faculty, Metallurgy and Materials Eng. Dep., 54187 Sakarya (Turkey); Fındık, Fehim [Sakarya University, Technology Faculty, Metallurgy and Materials Eng. Dep., 54187 Sakarya (Turkey) and International University of Sarajevo, Faculty of Engineering and Natural Sciences, Department of Mechanical Engineering, 71000 Sarajevo, Bosnia and Herzegovina (Bosnia and Herzegowina)

2013-11-05

Highlights: •Microstructural and mechanical properties of injection molded Nickel 718 superalloy were studied. •The maximum sintered density achieved this study was 97.3% at 1290 °C for 3 hours. •Tensile strength of 1022 MPa and elongation of 5.3% were achieved for sintered-heat treated samples. -- Abstract: This study concerns with the determination of optimum production parameters for injection molding 718 superalloy parts. And at the same time, microstructural and mechanical characterization of these produced parts was also carried out. At the initial stage, 718 superalloy powders were mixed with a multi-component binder system for preparing feedstock. Then the prepared feedstock was granulated and shaped by injection molding. Following this operation, the shaped samples were subjected to the debinding process. These samples were sintered at different temperatures for various times. Samples sintered under the condition that gave way to the highest relative density (3 h at 1290 °C) were solution treated and aged respectively. Sintered, solution treated and aged samples were separately subjected to microstructural and mechanical characterization. Microstructural characterization operations such as X-ray diffraction, optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and elemental analysis showed that using polymeric binder system led to plentiful carbide precipitates to be occurred in the injection molded samples. It is also observed that the volume fractions of the intermetallic phases (γ′ and γ″) obtained by aging treatment were decreased due to the plentiful carbide precipitation in the samples. Mechanical characterization was performed by hardness measurements and tensile tests.

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

Authentication and distinction of Shenmai injection with HPLC fingerprint analysis assisted by pattern recognition techniques

Directory of Open Access Journals (Sweden)

Xue-Feng Lu

2012-10-01

Full Text Available In this paper, the feasibility and advantages of employing high performance liquid chromatographic (HPLC fingerprints combined with pattern recognition techniques for quality control of Shenmai injection were investigated and demonstrated. The Similarity Evaluation System was employed to evaluate the similarities of samples of Shenmai injection, and the HPLC generated chromatographic data were analyzed using hierarchical clustering analysis (HCA and soft independent modeling of class analogy (SIMCA. Consistent results were obtained to show that the authentic samples and the blended samples were successfully classified by SIMCA, which could be applied to accurate discrimination and quality control of Shenmai injection. Furthermore, samples could also be grouped in accordance with manufacturers. Our results revealed that the developed method has potential perspective for the original discrimination and quality control of Shenmai injection. Keywords: Shenmai injection, High performance liquid chromatography, Fingerprint, Pattern recognition

Radiation detectors laboratory; Laboratorio de detectores de radiacion

Energy Technology Data Exchange (ETDEWEB)

Ramirez J, F.J. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

1997-07-01

The Radiation detectors laboratory was established with the assistance of the International Atomic Energy Agency which gave this the responsibility to provide its services at National and regional level for Latin America and it is located at the ININ. The more expensive and delicate radiation detectors are those made of semiconductor, so it has been put emphasis in the use and repairing of these detectors type. The supplied services by this laboratory are: selection consultant, detectors installation and handling and associated systems. Installation training, preventive and corrective maintenance of detectors and detection systems calibration. (Author)

Applications of polyamide/cellulose fiber/wollastonite composites for microcellular injection molding

Science.gov (United States)

Herman Winata; Lih-Sheng Turng; Daniel F. Caulfield; Tom Kuster; Rick Spindler; Rod Jacobson

2003-01-01

In this study, a cellulose-fiber-reinforced Polyamide-6 (PA-6) composite, a hybrid composite (PA-6/cellulose/Wollastonite), and the neat PA-6 resin were injection molded into ASTM test–bar samples with conventional and microcellular injection molding. The impact and tensile strengths of molded samples were measured and the Scanning Electron Microscopy (SEM) images were...

Detector and System Developments for LHC Detector Upgrades

CERN Document Server

Mandelli, Beatrice; Guida, Roberto; Rohne, Ole; Stapnes, Steinar

2015-05-12

The future Large Hadron Collider (LHC) Physics program and the consequent improvement of the LHC accelerator performance set important challenges to all detector systems. This PhD thesis delineates the studies and strategies adopted to improve two different types of detectors: the replacement of precision trackers with ever increasingly performing silicon detectors, and the improvement of large gaseous detector systems by optimizing their gas mixtures and operation modes. Within the LHC tracker upgrade programs, the ATLAS Insertable B-layer (IBL) is the first major upgrade of a silicon-pixel detector. Indeed the overall ATLAS Pixel Detector performance is expected to degrade with the increase of luminosity and the IBL will recover the performance by adding a fourth innermost layer. The IBL Detector makes use of new pixel and front-end electronics technologies as well as a novel thermal management approach and light support and service structures. These innovations required complex developments and Quality Ass...

Neutron-damaged GaAs detectors for use in a Compton spectrometer

International Nuclear Information System (INIS)

Kammeraad, J.E.; Sale, K.E.; Wang, C.L.; Baltrusaitis, R.M.

1992-01-01

Detectors made of GaAs are being studies for use on the focal plane of a Compton spectrometer which measures 1-MeV to 25-MeV gamma rays with high energy resolution (1% or 100 keV, whichever is greater) and 200-ps time resolution. The detectors are GaAs chips that have been neutron-damaged to improve the time response. The detectors will be used to measure fast transient signals in the current mode. The properties of various GaAs detector configurations are being studied by bombarding sample detectors with short pulses of 4-MeV to 16-MeV electrons at the Linac Facility at EG ampersand G Energy Measurements, Inc., Santa Barbara Operations. Measurements of detector sensitivity and impulse response versus detector bias, thickness, and electron beam energy and intensity have been performed and are presented. 5 refs

Test of radiation hardness of pcCVD detectors

Energy Technology Data Exchange (ETDEWEB)

Schlemme, Steffen [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Technische Universitaet Darmstadt (Germany); Enders, Joachim [Technische Universitaet Darmstadt (Germany); Figuera, P.; Salamone, S. [LNS-INFN Catania (Italy); Fruehauf, J.; Kis, Mladen; Kratz, A.; Kurz, N.; Loechner, S.; Nociforo, Chiara; Schirru, Fabio; Szczepanczyk, B.; Traeger, M.; Visinka, R. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Musumarra, A. [LNS-INFN Catania (Italy); University of Catania (Italy)

2016-07-01

The new in-flight separator Super-FRS is under construction at the Facility for Antiproton and Ion Research (FAIR, Darmstadt). Ion rates up to 3 x 10{sup 11} {sup 238}U/spill demand an adaption of detectors to a high radiation environment. A test experiment to investigate the radiation hardness of polycrystalline diamond detectors (pcCVD) was performed at the LNS-INFN in Catania using a {sup 12}C beam at 62 MeV/u and intensities of up to 1.5 pnA. The setup consisted of pcCVD strip detectors to measure the beam profile, a single crystal diamond detector to calibrate the ionisation chamber working in current mode as a beam intensity monitor and a pcCVD sample to be irradiated. The IC used was designed for FAIR and showed a stable counting rate allowing us to calibrate and perform beam intensity measurements with it. The total measured counts on the sample were 8.25 x 10{sup 11} counts/mm{sup 2} over a period of 60 hours. Digital waveforms of the pcCVD signals were taken with an oscilloscope and analysed. The results showed no change of the pcCVD signal properties during the entire irradiation.

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.

Study of gamma irradiation effects on the etching and optical properties of CR-39 solid state nuclear track detector and its application to uranium assay in soil samples

International Nuclear Information System (INIS)

Amol Mhatre; Kalsi, P.C.

2011-01-01

The gamma irradiation effects in the dose range of 2.5-43.0 Mrad on the etching and optical characteristics of CR-39 solid state nuclear track detector (SSNTD) have been studied by using etching and UV-Visible spectroscopic techniques. From the measured bulk etch rates at different temperatures, the activation energies for bulk etching at different doses have also been determined. It is seen that the bulk etch rates increase and the activation energies for bulk etching decrease with the increase in gamma dose. The optical band gaps of the unirradiated and the gamma -irradiated detectors determined from the UV-Visible spectra were found to decrease with the increase in gamma dose. These results have been explained on the basis of scission of the detector due to gamma irradiation. The present studies can be used for the estimation of gamma dose in the range of 2.5-43.0 Mrad and can also be used for estimating track registration efficiency in the presence of gamma dose. The CR-39 detector has also been applied for the assay of uranium in some soil samples of Jammu city. (author)

Triton burnup study using scintillating fiber detector on JT-60U

Energy Technology Data Exchange (ETDEWEB)

Harano, Hideki [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

1997-09-01

The DT fusion reactor cannot be realized without knowing how the fusion-produced 3.5 MeV {alpha} particles behave. The {alpha} particles` behavior can be simulated using the 1 MeV triton. To investigate the 1 MeV triton`s behavior, a new type of directional 14 MeV neutron detector, scintillating fiber (Sci-Fi) detector has been developed and installed on JT-60U in the cooperation with LANL as part of a US-Japan collaboration. The most remarkable feature of the Sci-Fi detector is that the plastic scintillating fibers are employed for the neutron sensor head. The Sci-Fi detector measures and extracts the DT neutrons from the fusion radiation field in high time resolution (10 ms) and wide dynamic range (3 decades). Triton burnup analysis code TBURN has been made in order to analyze the time evolution of DT neutron emission rate obtained by the Sci-Fi detector. The TBURN calculations reproduced the measurements fairly well, and the validity of the calculation model that the slowing down of the 1 MeV triton was classical was confirmed. The Sci-Fi detector`s directionality indicated the tendency that the DT neutron emission profile became more and more peaked with the time progress. In this study, in order to examine the effect of the toroidal field ripple on the triton burnup, R{sub p}-scan and n{sub e}-scan experiments have been performed. The R{sub p}-scan experiment indicates that the triton`s transport was increased as the ripple amplitude over the triton became larger. In the n{sub e}-scan experiment, the DT neutron emission showed the characteristic changes after the gas puffing injection. It was theoretically confirmed that the gas puffing was effective for the collisionality scan. (J.P.N.) 127 refs.

Gamma spectrometric analyses of environmental samples at PINSTECH

International Nuclear Information System (INIS)

Faruq, M.U.; Parveen, N.; Ahmed, B.; Aziz, A.

1979-01-01

Gamma spectrometric analyses of air and other environmental samples from PINSTECH were carried out. Air particulate samples were analyzed by a Ge(Li) detector on a computer-based multichannel analyzer. Other environmental samples were analyzed by a Na(T1) scintillation detector spectrometer and a multichannel analyzer with manual analysis. Concentration of radionuclides in the media was determined and the sources of their production were identified. Age of the fall out was estimated from the ratios of the fission products. (authors)

Detector with internal gain for short-wave infrared ranging applications

Science.gov (United States)

Fathipour, Vala; Mohseni, Hooman

2017-09-01

Abstarct.Highly sensitive photon detectors are regarded as the key enabling elements in many applications. Due to the low photon energy at the short-wave infrared (SWIR), photon detection and imaging at this band are very challenging. As such, many efforts in photon detector research are directed toward improving the performance of the photon detectors operating in this wavelength range. To solve these problems, we have developed an electron-injection (EI) technique. The significance of this detection mechanism is that it can provide both high efficiency and high sensitivity at room temperature, a condition that is very difficult to achieve in conventional SWIR detectors. An EI detector offers an overall system-level sensitivity enhancement due to a feedback stabilized internal avalanche-free gain. Devices exhibit an excess noise of unity, operate in linear mode, require bias voltage of a few volts, and have a cutoff wavelength of 1700 nm. We review the material system, operating principle, and development of EI detectors. The shortcomings of the first-generation devices were addressed in the second-generation detectors. Measurement on second-generation devices showed a high-speed response of ˜6 ns rise time, low jitter of less than 20 ps, high amplification of more than 2000 (at optical power levels larger than a few nW), unity excess noise factor, and low leakage current (amplified dark current ˜10 nA at a bias voltage of -3 V and at room temperature. These characteristics make EI detectors a good candidate for high-resolution flash light detection and ranging (LiDAR) applications with millimeter scale depth resolution at longer ranges compared with conventional p-i-n diodes. Based on our experimentally measured device characteristics, we compare the performance of the EI detector with commercially available linear mode InGaAs avalanche photodiode (APD) as well as a p-i-n diode using a theoretical model. Flash LiDAR images obtained by our model show that the EI

Diabetes Fear of Injecting and Self-Testing Questionnaire

DEFF Research Database (Denmark)

Mollema, E D; Snoek, Frank J; Pouwer, F

2000-01-01

OBJECTIVE: To study the psychometric properties of the Diabetes Fear of Injecting and Self-Testing Questionnaire (D-FISQ). RESEARCH DESIGN AND METHODS: Two groups of patients were studied. Sample A consisted of 252 insulin-treated diabetes patients. Sample B incorporated 24 insulin-treated patients......-injecting or self-testing had higher scores on FSI (P = 0.095) and FST (P = 0.01). EFA yielded 2 separate factors, FSI and FST. CONCLUSIONS: Results from this study support reliability and validity of the D-FISQ, a self-report instrument that can be used for both clinical and research purposes....

Cross section measurements for quasi-elastic neutrino-nucleus scattering with the MINOS near detector

Energy Technology Data Exchange (ETDEWEB)

Dorman, Mark Edward [Univ. College London, Bloomsbury (United Kingdom)

2008-04-01

The Main Injector Neutrino Oscillation Search (MINOS) is a long baseline neutrino oscillation experiment based at the Fermi National Accelerator Laboratory (FNAL) in Chicago, Illinois. MINOS measures neutrino interactions in two large iron-scintillator tracking/sampling calorimeters; the Near Detector on-site at FNAL and the Far Detector located in the Soudan mine in northern Minnesota. The Near Detector has recorded a large number of neutrino interactions and this high statistics dataset can be used to make precision measurements of neutrino interaction cross sections. The cross section for charged-current quasi-elastic scattering has been measured by a number of previous experiments and these measurements disagree by up to 30%. A method to select a quasi-elastic enriched sample of neutrino interactions in the MINOS Near Detector is presented and a procedure to fit the kinematic distributions of this sample and extract the quasi-elastic cross section is introduced. The accuracy and robustness of the fitting procedure is studied using mock data and finally results from fits to the MINOS Near Detector data are presented.

Cross section measurements for quasi-elastic neutrino-nucleus scattering with the MINOS near detector

International Nuclear Information System (INIS)

Dorman, Mark Edward

2008-01-01

The Main Injector Neutrino Oscillation Search (MINOS) is a long baseline neutrino oscillation experiment based at the Fermi National Accelerator Laboratory (FNAL) in Chicago, Illinois. MINOS measures neutrino interactions in two large iron-scintillator tracking/sampling calorimeters; the Near Detector on-site at FNAL and the Far Detector located in the Soudan mine in northern Minnesota. The Near Detector has recorded a large number of neutrino interactions and this high statistics dataset can be used to make precision measurements of neutrino interaction cross sections. The cross section for charged-current quasi-elastic scattering has been measured by a number of previous experiments and these measurements disagree by up to 30%. A method to select a quasi-elastic enriched sample of neutrino interactions in the MINOS Near Detector is presented and a procedure to fit the kinematic distributions of this sample and extract the quasi-elastic cross section is introduced. The accuracy and robustness of the fitting procedure is studied using mock data and finally results from fits to the MINOS Near Detector data are presented

Detector response restoration in image reconstruction of high resolution positron emission tomography

International Nuclear Information System (INIS)

Liang, Z.

1994-01-01

A mathematical method was studied to model the detector response of high spatial-resolution positron emission tomography systems consisting of close-packed small crystals, and to restore the resolution deteriorated due to crystal penetration and/or nonuniform sampling across the field-of-view (FOV). The simulated detector system had 600 bismuth germanate crystals of 3.14 mm width and 30 mm length packed on a single ring of 60 cm diameter. The space between crystal was filled up with lead. Each crystal was in coincidence with 200 opposite crystals so that the FOV had a radius of 30 cm. The detector response was modeled based on the attenuating properties of the crystals and the septa, as well as the geometry of the detector system. The modeled detector-response function was used to restore the projections from the sinogram of the ring-detector system. The restored projections had a uniform sampling of 1.57 mm across the FOV. The crystal penetration and/or the nonuniform sampling were compensated in the projections. A penalized maximum-likelihood algorithm was employed to accomplish the restoration. The restored projections were then filtered and backprojected to reconstruct the image. A chest phantom with a few small circular ''cold'' objects located at the center and near the periphery of FOV was computer generated and used to test the restoration. The reconstructed images from the restored projections demonstrated resolution improvement off the FOV center, while preserving the resolution near the center

Simultaneous Scanning Electron Microscope Imaging of Topographical and Chemical Contrast Using In-Lens, In-Column, and Everhart-Thornley Detector Systems.

Science.gov (United States)

Zhang, Xinming; Cen, Xi; Ravichandran, Rijuta; Hughes, Lauren A; van Benthem, Klaus

2016-06-01

The scanning electron microscope provides a platform for subnanometer resolution characterization of material morphology with excellent topographic and chemical contrast dependent on the used detectors. For imaging applications, the predominantly utilized signals are secondary electrons (SEs) and backscattered electrons (BSEs) that are emitted from the sample surface. Recent advances in detector technology beyond the traditional Everhart-Thornley geometry have enabled the simultaneous acquisition and discrimination of SE and BSE signals. This study demonstrates the imaging capabilities of a recently introduced new detector system that consists of the combination of two in-lens (I-L) detectors and one in-column (I-C) detector. Coupled with biasing the sample stage to reduce electron-specimen interaction volumes, this trinity of detector geometry allows simultaneous acquisition of signals to distinguish chemical contrast from topographical changes of the sample, including the identification of surface contamination. The I-C detector provides 4× improved topography, whereas the I-L detector closest to the sample offers excellent simultaneous chemical contrast imaging while not limiting the minimization of working distance to obtain optimal lateral resolution. Imaging capabilities and contrast mechanisms for all three detectors are discussed quantitatively in direct comparison to each other and the conventional Everhart-Thornley detector.

Oxide layers for silicon detector protection against enviroment effects

International Nuclear Information System (INIS)

Bel'tsazh, E.; Brylovska, I.; Valerian, M.

1986-01-01

It is shown that for protection of silicon detectors of nuclear radiations oxide layers could be used. The layers are produced by electrochemical oxidation of silicon surface with the following low-temperature annealing. These layers have characteristics similar to those for oxide layers produced by treatment of silicon samples at elevated temperature in oxygen flow. To determine properties of oxide layers produced by electrochemical oxidation the α-particle back-scattering method and the method of volt-farad characteristics were used. Protection properties of such layers were checked on the surface-barrier detectors. It was shown that protection properties of such detectors were conserved during long storage at room temperature and during their storage under wet-bulb temperature. Detectors without protection layer have worsened their characteristics

Stability study of methotrexate in 0.9% sodium chloride injection and 5% dextrose injection with limit tests for impurities