WorldWideScience
1

Bayesian Methods for Radiation Detection and Dosimetry  

CERN Document Server

We performed work in three areas: radiation detection, external and internal radiation dosimetry. In radiation detection we developed Bayesian techniques to estimate the net activity of high and low activity radioactive samples. These techniques have the advantage that the remaining uncertainty about the net activity is described by probability densities. Graphs of the densities show the uncertainty in pictorial form. Figure 1 below demonstrates this point. We applied stochastic processes for a method to obtain Bayesian estimates of 222Rn-daughter products from observed counting rates. In external radiation dosimetry we studied and developed Bayesian methods to estimate radiation doses to an individual with radiation induced chromosome aberrations. We analyzed chromosome aberrations after exposure to gammas and neutrons and developed a method for dose-estimation after criticality accidents. The research in internal radiation dosimetry focused on parameter estimation for compartmental models from observed comp...

Groe, Peter G

2002-01-01

2

Radiation detection device and a radiation detection method  

International Nuclear Information System (INIS)

A radiation detection device is described including at least one scintillator in the path of radiation emissions from a distributed radiation source; a plurality of photodetectors for viewing each scintillator; a signal processing means, a storage means, and a data processing means that are interconnected with one another and connected to said photodetectors; and display means connected to the data processing means to locate a plurality of radiation sources in said distributed radiation source and to provide an image of the distributed radiation sources. The storage means includes radiation emission response data and location data from a plurality of known locations for use by the data processing means to derive a more accurate image by comparison of radiation responses from known locations with radiation responses from unknown locations. (auth)

3

Rubella virus detection by ELISA method in exposed radiation workers  

International Nuclear Information System (INIS)

Objective: A rapid diagnosis method was developed to detect Rubella virus infection in radiation workers. Methods: Modified ELISA method was used to detect the level of lgG and lgM antibodies in 514 in Jinan district. Results: 90.47% of 514 cases was shown to be resistant against Rubella virus; 6.42% were sensitive type; 0.78% belonged to be reinfected. Conclusion: Detection of Rubella virus in exposed radiation workers was imperative, and vaccine against Rubella virus was also needed to eliminate the infection risk. (authors)

4

Method and circuit for stabilizing conversion gain of radiation detectors of a radiation detection system  

International Nuclear Information System (INIS)

A method is described for calibrating the gain of an array of radiation detectors of a radiation detection system comprising the steps of: (a) measuring in parallel for each radiation detector using a predetermined calibration point the energy map status, thereby obtaining an energy response vector whose elements correspond to the individual output of each radiation detector, each predetermined calibration point being a prescribed location corresponding to one of the radiation detectors; (b) multiplying that energy response vector with a predetermined deconvolution matrix, the deconvolution matrix being the inversion of a contribution matrix containing matrix elements C/sub IJ/, each such matrix element C/sub IJ/ of the contribution matrix representing the relative contribution level of a radiation detector j of the detection system for a point radiation source placed at a location i, thereby obtaining a gain vector product for the radiation detectors; (c) adjusting the gains of the radiation detectors with respect to the gain vector product such that a unity gain vector is essentially obtained; (d) measuring again the energy map status according to step (a); and (e) if the energy map status fails to essentially produce a unity gain vector repeat steps (a) to (d) until the energy map status substantially corresponds to unity

5

Radiation sensitive devices and systems for detection of radioactive materials and related methods  

Energy Technology Data Exchange (ETDEWEB)

Radiation sensitive devices include a substrate comprising a radiation sensitive material and a plurality of resonance elements coupled to the substrate. Each resonance element is configured to resonate responsive to non-ionizing incident radiation. Systems for detecting radiation from a special nuclear material include a radiation sensitive device and a sensor located remotely from the radiation sensitive device and configured to measure an output signal from the radiation sensitive device. In such systems, the radiation sensitive device includes a radiation sensitive material and a plurality of resonance elements positioned on the radiation sensitive material. Methods for detecting a presence of a special nuclear material include positioning a radiation sensitive device in a location where special nuclear materials are to be detected and remotely interrogating the radiation sensitive device with a sensor.

Kotter, Dale K

2014-12-02

6

Method for increased sensitivity of radiation detection and measurement  

Science.gov (United States)

Dose of radiation to which a body of crystalline material has been exposed is measured by exposing the body to optical radiation at a first wavelength, which is greater than about 540 nm, and measuring optical energy emitted from the body by luminescence at a second wavelength, which is longer than the first wavelength. Reduced background is accomplished by more thorough annealing and enhanced radiation induced luminescence is obtained by treating the crystalline material to coalesce primary damage centers into secondary damage centers.

Miller, Steven D. (Richland, WA)

1994-01-01

7

A modified proportional source method used for measuring the dead time of a radiation detecting system  

International Nuclear Information System (INIS)

This paper describes a method of measuring the dead time of a radiation detecting system using two radiation sources with the same spectrum and structure but different intensity. It can be used to precisely determine the dead time independent from counting rates, and the approximate values of the relative intensities of the sources can be obtained

8

Methods for detecting acceleration radiation in a Bose-Einstein condensate.  

Science.gov (United States)

We propose and study methods for detecting Unruh-like acceleration radiation effects in a Bose-Einstein condensate in a (1+1)-dimensional setup. The Bogoliubov vacuum of a Bose-Einstein condensate is used to simulate a scalar field theory, and accelerated atom dots or optical lattices serve as detectors of phonon radiation due to acceleration effects. In particular, we study the dispersive effects of the Bogoliubov spectrum on the ideal case of exact thermalization. Our results suggest that acceleration radiation effects can be observed using currently accessible experimental methods. PMID:18851268

Retzker, A; Cirac, J I; Plenio, M B; Reznik, B

2008-09-12

9

Radiation detection method and system using the sequential probability ratio test  

Science.gov (United States)

A method and system using the Sequential Probability Ratio Test to enhance the detection of an elevated level of radiation, by determining whether a set of observations are consistent with a specified model within a given bounds of statistical significance. In particular, the SPRT is used in the present invention to maximize the range of detection, by providing processing mechanisms for estimating the dynamic background radiation, adjusting the models to reflect the amount of background knowledge at the current point in time, analyzing the current sample using the models to determine statistical significance, and determining when the sample has returned to the expected background conditions.

Nelson, Karl E. (Livermore, CA); Valentine, John D. (Redwood City, CA); Beauchamp, Brock R. (San Ramon, CA)

2007-07-17

10

Novel detection methods for radiation-induced electron-hole pairs.  

Energy Technology Data Exchange (ETDEWEB)

Most common ionizing radiation detectors typically rely on one of two general methods: collection of charge generated by the radiation, or collection of light produced by recombination of excited species. Substantial efforts have been made to improve the performance of materials used in these types of detectors, e.g. to raise the operating temperature, to improve the energy resolution, timing or tracking ability. However, regardless of the material used, all these detectors are limited in performance by statistical variation in the collection efficiency, for charge or photons. We examine three alternative schemes for detecting ionizing radiation that do not rely on traditional direct collection of the carriers or photons produced by the radiation. The first method detects refractive index changes in a resonator structure. The second looks at alternative means to sense the chemical changes caused by radiation on a scintillator-type material. The final method examines the possibilities of sensing the perturbation caused by radiation on the transmission of a RF transmission line structure. Aspects of the feasibility of each approach are examined and recommendations made for further work.

Nordquist, Christopher Daniel; Cich, Michael Joseph; Vawter, Gregory Allen; Derzon, Mark Steven; Martinez, Marino John

2010-09-01

11

Apparatus and method for the simultaneous detection of neutrons and ionizing electromagnetic radiation  

Science.gov (United States)

A sensor for simultaneously detecting neutrons and ionizing electromagnetic radiation comprising: a sensor for the detection of gamma radiation, the sensor defining a sensing head; the sensor further defining an output end in communication with the sensing head; and an exterior neutron-sensitive material configured to form around the sensing head; wherein the neutron-sensitive material, subsequent to the capture of the neutron, fissions into an alpha-particle and a .sup.7 Li ion that is in a first excited state in a majority of the fissions, the first excited state decaying via the emission of a single gamma ray at 478 keV which can in turn be detected by the sensing head; and wherein the sensing head can also detect the ionizing electromagnetic radiation from an incident radiation field without significant interference from the neutron-sensitive material. A method for simultaneously detecting neutrons and ionizing electromagnetic radiation comprising the steps of: providing a gamma ray sensitive detector comprising a sensing head and an output end; conforming an exterior neutron-sensitive material configured to form around the sensing head of the detector; capturing neutrons by the sensing head causing the neutron-sensitive material to fission into an alpha-particle and a .sup.7 Li ion that is in a first excited state in a majority of the fissions, the state decaying via the emission of a single gamma ray at 478 keV; sensing gamma rays entering the detector through the neutron-sensitive material; and producing an output through a readout device coupled to the output end; wherein the detector provides an output which is proportional to the energy of the absorbed ionizing electromagnetic radiation.

Bell, Zane W. (Oak Ridge, TN)

2000-01-01

12

A simple and efficient object detection method based on saliency measure for infrared radiation image  

Science.gov (United States)

Detection of visually salient objects plays an important role in applications such as object segmentation, adaptive compression, object recognition, etc. A simple and computationally efficient method is presented in this paper for detecting visually salient objects in Infrared Radiation images. The proposed method can be divided into three steps. Firstly, the infrared image is pre-processed to increase the contrast between objects and background. Secondly, the spectral residual of the pre-processed image is extracted in the log spectrum, then via corresponding inverse transform and threshold segmentation we can get the rough regions of the salient objects. Finally, we apply a sliding window to acquire the explicit position of the salient objects using the probabilistic interpretation of the semi-local feature contrast which is estimated by comparing the gray level distribution of the object and the surrounding area in the original image. And as we change the size of the sliding window, different size of objects can be found out. In our proposed method, the first two steps combined together to play a role in narrowing the searching region and thus accelerating computation. The third procedure is applied to extract the salient objects. We test our method on abundant amount of Infrared Radiation images, and the results show that our saliency detection based object detection method is effective and robust.

Sun, Zhaolei; Hui, Bin

2014-11-01

13

Method for Creating and Detecting Hydrogen Sorption Sites Using Gamma Radiation  

CERN Document Server

Using gamma radiation and volumetric analysis of desorbed gas, hydrogen gas bonding sites have been created and detected in select materials. Desorption of hydrogen was followed over a benign temperature-pressure range. The extent of active site formation depends on radiation dosage; quenching of sites occurs over prolonged heating at low pressures. An estimate of the hydrogen bonding energy can be made on the basis of a partial temperature profile of the gas released at one atmosphere pressure. It appears that the bonding energy can be adjusted by mixing candidate materials. A guide for further investigation and application of the method is outlined.

Muga, Barbara G

2010-01-01

14

Apparatus and method for detecting electromagnetic radiation using electron photoemission in a micromechanical sensor  

Science.gov (United States)

A micromechanical sensor and method for detecting electromagnetic radiation involve producing photoelectrons from a metal surface in contact with a semiconductor. The photoelectrons are extracted into the semiconductor, which causes photo-induced bending. The resulting bending is measured, and a signal corresponding to the measured bending is generated and processed. A plurality of individual micromechanical sensors can be arranged in a two-dimensional matrix for imaging applications.

Datskos, Panagiotis G. (Knoxville, TN); Rajic, Slobodan (Knoxville, TN); Datskou, Irene C. (Knoxville, TN); Egert, Charles M. (Oak Ridge, TN)

2002-01-01

15

PTTL method applied to UV radiation detection during refractive surgery using excimer laser  

International Nuclear Information System (INIS)

The method of photo-transferred thermoluminescence (PTTL), using CaSO4:Dy pellets produced at IPEN as sensitive material, was used to detect the spread laser radiation inside the surgery room during refractive surgical procedures using ArF excimer lasers. The purpose of this work was to study the viability of performing the ultraviolet radiation (UVR) exposure detection of patients and the hospital's surgical staff during a refractive surgery. The CaSO4:Dy pellets were positioned at different distances from the laser source inside the surgery room: patient's (?0.15 m), surgeon's (?0.5 m) and nurse's (?1.0 m) foreheads, lateral (?1.5 m) and back (?4.0 m) walls. The measurements of PTTL were carried out at two different conditions: five surgeries, each one taking ?10 min, and during a period of 4 h (cumulative), when several operations were performed. The detectors positioned as far as 4.0 m from the UV laser source were sensitised, making the UVR detection feasible at large source-detector distances. The absorbed energy was detected in the range from 40 ?J to 30 mJ during a surgery. This result indicates that the method studied can be used to detect the spread UVR. (authors)

16

FISH as A method for detection of radiation Induced genetic damage  

International Nuclear Information System (INIS)

Fluorescence in situ hybridization (FISH) has been considered as a suitable method for rapid and easy detection of chromosome aberrations. In contrast to the standard conventional staining procedure, this technique enables the detection and specification of stable chromosomal re-arrangements, which are compatible with cellular division and thus, they could be transmitted from common ancestral to next cell generations. FISH chromosome - specific painting probes have been effectively applied for the detection of chromosomal damage after exposure to radiation. During last years, several specific fluorescent labeled probes were performed that allowed precise detection of centromeres, sub-telomeres or other regions (sequences) in genome. Our paper deals with describing of different types of FISH probes and their possibilities for application in radiobiology. (authors)

17

Methods for radiation detection and characterization using a multiple detector probe  

Energy Technology Data Exchange (ETDEWEB)

Apparatuses, methods, and systems relating to radiological characterization of environments are disclosed. Multi-detector probes with a plurality of detectors in a common housing may be used to substantially concurrently detect a plurality of different radiation activities and types. Multiple multi-detector probes may be used in a down-hole environment to substantially concurrently detect radioactive activity and contents of a buried waste container. Software may process, analyze, and integrate the data from the different multi-detector probes and the different detector types therein to provide source location and integrated analysis as to the source types and activity in the measured environment. Further, the integrated data may be used to compensate for differential density effects and the effects of radiation shielding materials within the volume being measured.

Akers, Douglas William; Roybal, Lyle Gene

2014-11-04

18

Radiation detection and measurement  

International Nuclear Information System (INIS)

One of two purposes of this book is to serve as a textbook for a course in nuclear instrumentation or radiation measurements at the advanced undergraduate or beginning graduate level. More material is included than could possibly be covered in a one-year course, and this was done so that the book could serve its second purpose - as a general review or reference for experienced professionals who are actively involved in radiation measurements. The first 150 pages are devoted to radiation sources, radiation interactions, general properties of radiation detectors, counting statistics, and error prediction. Units of measurement are included, and numerical values and examples are given that provide the reader with a working knowledge as well as a theoretical one. The central portion of the book details specific properties of the basic radiation detection devices, and covers gas-filled detectors, scintillation counters, semiconductor detectors, and neutron detectors. Sections on gamma-ray spectroscopy and neutron spectroscopy are included. The traditional detection devices, such as the semiconductor diodes and lithium drifted detectors, are discussed. Newer devices are also described, i.e., the cadmium telluride detector and bismuth germanate. The last section of the book covers detector electronics and pulse processing, including linear and logic pulse function and multi-channel pulse analysis. There is an additional chapter on background radiation and detector shielding akground radiation and detector shielding and a short appendix on the biologic effects of radiation and exposure limits. This book does not include any discussion of imaging devices, but it does contain all the necessary information on the basics of instruments and methods for the detection and measurement of ionizing radiation

19

Counterbalanced radiation detection system  

International Nuclear Information System (INIS)

A counterbalanced radiation detection system is described comprising: (a) a stand; (b) a first radiation detector; (c) a first radiation detector arm means for tiltably connecting the first radiation detector with the stand; (d) a second radiation detector; (e) a second radiation detector arm means for tiltably connecting the second radiation detector with the stand, whereby the tilting angles of the radiation detector arm means define a distance between the radiation detectors; and (f) a torque transforming means connected between the first and second radiation detector arm means for transforming the torque created by one of the radiation detectors in a sense opposed to the torque created by the other radiation detector

20

Sentinel node detection of patients with breast cancer by radionuclide method. Consideration of radiation safety  

International Nuclear Information System (INIS)

Sentinel node was detected by 99mTc labeled nanocolloid in five patients with breast cancer. Surgery of breast cancer was done at 16 hours after the administration of 74 BMq of 99mTc labeled nanocolloid. Sentinel node was searched by scintigraphy prior to surgery and by gamma-probe during surgery. Radioactivity of injected site, sentinel nodes, blood contaminated gauze, and other garbage was measured by GM detector. Radiation to medical staffs was monitored by a pocket radiation detector and film batches. Sentinel nodes were successfully detected both by scintigraphy and gamma-detector. More than 70% of radioactivity remained in the administered site at 16 hours. Small amount of radioactivity was detectable in the sentinel node. Almost no radioactivity was detectable in blood contaminated gauze and other garbage. Radiation dose to the main surgeon was 4 to 6 ?Sv per surgery by a pocket radiation detector. Radiation dose to the assistant surgeon was 2 ?Sv per surgery. Radiation dose by labeling or injection was 0 to 1 ?Sv per procedure. No detectable radiation was measured by film batches. It is concluded that the detection of sentinel node by 99mTc labeled nanocolloid is a safe procedure from the point of radiation safety consideration. (author)

21

Level crossing analysis of cosmic microwave background radiation: a method for detecting cosmic strings  

International Nuclear Information System (INIS)

In this paper we study the footprint of cosmic string as the topological defects in the very early universe on the cosmic microwave background radiation. We develop the method of level crossing analysis in the context of the well-known Kaiser-Stebbins phenomenon for exploring the signature of cosmic strings. We simulate a Gaussian map by using the best fit parameter given by WMAP-7 and then superimpose cosmic strings effects on it as an incoherent and active fluctuations. In order to investigate the capability of our method to detect the cosmic strings for the various values of tension, G?, a simulated pure Gaussian map is compared with that of including cosmic strings. Based on the level crossing analysis, the superimposed cosmic string with G??>4 × 10?9 in the simulated map without instrumental noise and the resolution R = 1' could be detected. In the presence of anticipated instrumental noise the lower bound increases just up to G??>5.8 × 10?9

22

Level crossing analysis of cosmic microwave background radiation: a method for detecting cosmic strings  

Energy Technology Data Exchange (ETDEWEB)

In this paper we study the footprint of cosmic string as the topological defects in the very early universe on the cosmic microwave background radiation. We develop the method of level crossing analysis in the context of the well-known Kaiser-Stebbins phenomenon for exploring the signature of cosmic strings. We simulate a Gaussian map by using the best fit parameter given by WMAP-7 and then superimpose cosmic strings effects on it as an incoherent and active fluctuations. In order to investigate the capability of our method to detect the cosmic strings for the various values of tension, G?, a simulated pure Gaussian map is compared with that of including cosmic strings. Based on the level crossing analysis, the superimposed cosmic string with G??>4 × 10{sup ?9} in the simulated map without instrumental noise and the resolution R = 1' could be detected. In the presence of anticipated instrumental noise the lower bound increases just up to G??>5.8 × 10{sup ?9}.

Movahed, M. Sadegh [Department of Physics, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of); Khosravi, Shahram, E-mail: m.s.movahed@ipm.ir, E-mail: khosravi@ipm.ir [Department of Physics, Faculty of Science, Tarbiat Moallem University, Tehran (Iran, Islamic Republic of)

2011-03-01

23

Level Crossing Analysis of Cosmic Microwave Background Radiation: A method for detecting cosmic strings  

CERN Document Server

In this paper we study the footprint of cosmic string as the topological defects in the very early universe on the cosmic microwave background radiation. We develop the method of level crossing analysis in the context of the well-known Kaiser-Stebbins phenomenon for exploring the signature of cosmic strings. We simulate a Gaussian map by using the best fit parameter given by WMAP-7 and then superimpose cosmic strings effects on it as an incoherent and active fluctuations. In order to investigate the capability of our method to detect the cosmic strings for the various values of tension, $G\\mu$, a simulated pure Gaussian map is compared with that of including cosmic strings. Based on the level crossing analysis, the superimposed cosmic string with $G\\mu\\gtrsim 4\\times 10^{-9}$ in the simulated map without instrumental noise and the resolution $R=1'$ could be detected. In the presence of anticipated instrumental noise the lower bound increases just up to $G\\mu\\gtrsim 5.8\\times 10^{-9}$.

Movahed, M Sadegh

2010-01-01

24

Detection of radiation-induced lung injury by 99mTc-DTPA aerosol inhalation method  

International Nuclear Information System (INIS)

We prospectively monitored pulmonary 99mTc-diethylene triamine penta acetate (DTPA) clearance in patients who received chest radiation therapy in order to determine whether this method allows us to predict the development of radiation pneumonitis. The rate constant of pulmonary 99mTc-DTPA clearance (k; %/min) was used to assess pulmonary epithelial damage. Fifteen nonsmoking patients who underwent radiation therapy were studied. The subjects included 4 patients who had already developed radiation pneumonitis at the time of study, and 11 in whom we prospectively observed 99mTc-DTPA clearance serially during the course of chest radiation therapy. In the 4 patients with pre-existing radiation pneumonitis, the mean k value obtained from the area with infiltration on the chest X-ray was significantly greater than that from the opposite lung (p99mTc-DTPA clearance may be useful for predicting the development of radiation pneumonitis. (author)

25

Counterbalanced radiation detection device  

International Nuclear Information System (INIS)

A counterbalanced radiation detection device is described which consists of: (a) a base; (b) a radiation detector having a known weight; (c) means connected with the radiation detector and the base for positioning the radiation detector in different heights with respect to the base; (d) electronic component means movably mounted on the base for counterbalancing the weight of the radiation detector; (e) means connected with the electronic component means and the radiation detector positioning means for positioning the electronic component means in different heights with respect to the base opposite to the heights of the radiation detector; (f) means connected with the radiation detector and the base for shifting the radiation detector horizontally with respect to the base; and (g) means connected with the electronic component means and the radiation detector shifting means for shifting the electronic component means horizontally with respect to the base in opposite direction to shifting of the radiation detector

26

Nanoscintillators for radiation detection  

Science.gov (United States)

In the search for faster, more effective methods for detection of and protection against radiological weapons, advances in materials for radiation detection are a critical component of any successful strategy. This work focuses on producing inexpensive, but highly sensitive, nanoparticle alternatives to existing single-crystal installations. Attention is given to particular types of promising inorganic scintillators: LaF3, yttrium-aluminum-garnet (YAG), and SrF2, each one an inorganic host doped with additional elements that encourage luminescent decay and increase effective Z-value. I examine the possible routes to synthesize these compounds, and the difficulties and benefits of each method. After synthesizing these materials, testing was performed to determine comparative performance against each other and commercial solutions, identify structural and compositional characteristics, and explore routes for fixing the scintillators into a detector assembly. The unifying goal is to develop a scintillating material suitable for consistent dosimetry and radio-isotope identification applications.

Hall, Ryan Gregory

27

Detection of reciprocal chromosome translocations as an indicator of organism exposure to ionizing radiation by FISH-WCP method  

International Nuclear Information System (INIS)

Chromosome translocations are considered to be the gold standard for assessing ionizing radiation exposure. Because translocations are inherently more stable through cell division than dicentrics, translocations have become the aberration of choice for evaluating many types of exposure. Fluorescence in situ hybridization with whole chromosome painting probes (FISH-WCP) has been shown to be a rapid method of detecting chromosomal rearrangements, and appears to be especially useful for analysis of induced translocations. The present paper shortly describes FISH-WCP method for detection of reciprocal translocations as indicators of exposure to ionizing radiation. (authors)

28

Principle and methods for measurement of snow water equivalent by detection of natural gamma radiation  

International Nuclear Information System (INIS)

The underlying principles for snow cover determination by use of terrestrial gamma radiation are presented. Several of the methods that have been proposed to exploit the effect are discussed, and some of the more important error sources for the different methods are listed. In conclusion an estimate of the precision that can be obtained by these methods is given. (Auth.)

29

Apparatus and method for examining a blood vessel of interest using radiation detected outside the body  

International Nuclear Information System (INIS)

A gamma camera is described in detail for use in examining the blood circulation in vessels adjacent to the heart. The radiation source (e.g. 68Ga) emits positrons whose annihilation is localised and produces two 0.115 MeV gamma rays in exactly opposite directions. By detecting both gamma rays in coincidence in position sensitive multi-wire proportional chambers, lines may be drawn between detected pairs and the intersection of of all such pairs will define the position of the positron emitting source. The radiation source may be tracked in three dimensions by suitably arranging the detectors around the patient's chest. The position of the radiation source can be recorded as a function of time and hence provide information about the velocity of blood flow through each coronary artery. This information may help determine the extent, severity and location of stenotic lesions of the coronary arteries. (U.K.)

30

A new method to eliminate the influence of intense background radiation on photoelectric detection  

International Nuclear Information System (INIS)

By taking PV-type InSb detector for example, the dynamics model describing the carriers transportation is established, and then the function relation between the photovoltage and the incident light power density is obtained. Thus, a new method to eliminate the disturbance of intense background radiation to PV-type InSb detector is proposed. Contrasting with the conventional zero-set method, such a new method can be applicable to more powerful background radiation accurately. Furthermore, the validity of the new method and the rationality of the theoretical model are testified experimentally

31

Detecting methods and statistical models in studying on DNA double-strand breaks induced by ionizing radiation  

International Nuclear Information System (INIS)

A DNA molecule is both the carrier of biological information and the main target of biological effects induced by ionizing radiation. Irradiation leads to many types of DNA damage by the direct and the indirect radiation effect. DNA double-strand breaks (DSB) induced by ionizing radiation represent the primary damage of all bio-effects. Currently, the detecting methods dealing with DSB include raman spectroscopy analysis, atomic force microscopy analysis, single cell gel electrophoresis, pulsed-field gel electrophoresis, ? H2AX analysis and premature chromo- some condensation analysis, etc. And the statistical models of DNA DSB involve in the random fracture model, the moment method, the tsallis entropy model and the average molecular weight method. Both of them have been dis- cussed in this paper. Finally, the research prospect of the DNA DSB radiation hotspot is presented.. (authors)

32

Scintillator assembly for alpha radiation detection and an associated method of making  

Science.gov (United States)

A scintillator assembly for use in conjunction with a photomultiplier or the like in the detection of alpha radiation utilizes a substrate or transparent yttrium aluminum garnet and a relatively thin film of cerium-doped yttrium aluminum garnet coated upon the substrate. The film material is applied to the substrate in a sputtering process, and the applied film and substrate are annealed to effect crystallization of the film upon the substrate. The resultant assembly provides relatively high energy resolution during use in a detection instrument and is sufficiently rugged for use in field environments.

Lauf, Robert J. (Oak Ridge, TN); McElhaney, Stephanie A. (Oak Ridge, TN); Bates, John B. (Oak Ridge, TN)

1994-01-01

33

Electrets for ? radiation detection  

International Nuclear Information System (INIS)

The use of electrets for ? radiation detection is described. Such a detector showed a linear decrease of charge with increasing absorbed dose over a certain range of charge of the electret. Different radiation field geometries and wall materials for the outer jacket were tested, in order to obtain the highest sensitivity and energy independence of the electret response. This was obtained with perpendicular geometry (electret axis perpendicular to the radiation field) and open detector (without outer jacket); the lowest absorbed dose measurable was 2,5 ?Gy for 90Sr-90Y and 204Tl sources. Depending on the ? dose range, other conditions must be chosen

34

Including shielding effects in application of the TPCA method for detection of embedded radiation sources.  

Energy Technology Data Exchange (ETDEWEB)

Conventional full spectrum gamma spectroscopic analysis has the objective of quantitative identification of all the radionuclides present in a measurement. For low-energy resolution detectors such as NaI, when photopeaks alone are not sufficient for complete isotopic identification, such analysis requires template spectra for all the radionuclides present in the measurement. When many radionuclides are present it is difficult to make the correct identification and this process often requires many attempts to obtain a statistically valid solution by highly skilled spectroscopists. A previous report investigated using the targeted principal component analysis method (TPCA) for detection of embedded sources for RPM applications. This method uses spatial/temporal information from multiple spectral measurements to test the hypothesis of the presence of a target spectrum of interest in these measurements without the need to identify all the other radionuclides present. The previous analysis showed that the TPCA method has significant potential for automated detection of target radionuclides of interest, but did not include the effects of shielding. This report complements the previous analysis by including the effects of spectral distortion due to shielding effects for the same problem of detection of embedded sources. Two examples, one with one target radionuclide and the other with two, show that the TPCA method can successfully detect shielded targets in the presence of many other radionuclides. The shielding parameters are determined as part of the optimization process using interpolation of library spectra that are defined on a 2D grid of atomic numbers and areal densities.

Johnson, William C.; Shokair, Isaac R.

2011-12-01

35

Scintillator assembly for alpha radiation detection and method of making the assembly  

Science.gov (United States)

A scintillator assembly for use in the detection of alpha radiation includes a body of optically-transparent epoxy and an amount of phosphor particles embedded within the body adjacent one surface thereof. When making the body, the phosphor particles are mixed with the epoxy when in an uncured condition and permitted to settle to the bottom surface of a mold within which the epoxy/phosphor mixture is contained. When the mixture subsequently cures to form a hardened body, the one surface of the body which cured against the bottom surface of the mold is coated with a thin layer of opaque material for preventing ambient light form entering the body through the one surface. The layer of opaque material is thereafter coated with a layer of protective material to provide the assembly with a damage-resistant entrance window.

McElhaney, Stephanie A. (Oak Ridge, TN); Bauer, Martin L. (Oak Ridge, TN); Chiles, Marion M. (Koxville, TN)

1992-01-01

36

Ionizing radiation as optimization method for aluminum detection from drinking water samples  

International Nuclear Information System (INIS)

The presence of organic compounds in water samples is often responsible for metal complexation; depending on the analytic method, the organic fraction may dissemble the evaluation of the real values of metal concentration. Pre-treatment of the samples is advised when organic compounds are interfering agents, and thus sample mineralization may be accomplished by several chemical and/or physical methods. Here, the ionizing radiation was used as an advanced oxidation process (AOP), for sample pre-treatment before the analytic determination of total and dissolved aluminum by ICP-OES in drinking water samples from wells and spring source located at Billings dam region. Before irradiation, the spring source and wells' samples showed aluminum levels of 0.020 mg/l and 0.2 mg/l respectively; after irradiation, both samples showed a 8-fold increase of aluminum concentration. These results are discussed considering other physical and chemical parameters and peculiarities of sample sources. (author)

37

Ionizing radiation as optimization method for aluminum detection from drinking water samples  

Energy Technology Data Exchange (ETDEWEB)

The presence of organic compounds in water samples is often responsible for metal complexation; depending on the analytic method, the organic fraction may dissemble the evaluation of the real values of metal concentration. Pre-treatment of the samples is advised when organic compounds are interfering agents, and thus sample mineralization may be accomplished by several chemical and/or physical methods. Here, the ionizing radiation was used as an advanced oxidation process (AOP), for sample pre-treatment before the analytic determination of total and dissolved aluminum by ICP-OES in drinking water samples from wells and spring source located at Billings dam region. Before irradiation, the spring source and wells' samples showed aluminum levels of 0.020 mg/l and 0.2 mg/l respectively; after irradiation, both samples showed a 8-fold increase of aluminum concentration. These results are discussed considering other physical and chemical parameters and peculiarities of sample sources. (author)

Bazante-Yamguish, Renata; Geraldo, Aurea Beatriz C.; Moura, Eduardo; Manzoli, Jose Eduardo, E-mail: ryamaguishi@ipen.br, E-mail: ageraldo@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2013-07-01

38

An improved method to detect small amounts of radiation damage in DNA of eukaryotic cells  

International Nuclear Information System (INIS)

Centrifugation in neutral sucrose gradients has a high sensitivity in the detection of SSBs, but the technique is prone to errors introduced by the absorption of DNA aggregates onto the wall of the centrifuge tube. Ethidium bromide (EtBr) was added to the sucrose gradient at a concentration (30 ?g/ml) chosen so that the removal of negative superhelical DNA turns was compensated for by the establishment of positive ones. The position of the EtBr-DNA complex in the gradient was located as a red band under 350 nm illumination. Details are given of the application of the method in the detection of the formation and repair of SSBs in irradiated mouse thymus cells. (UK)

39

Data derandomizer and method of operation for radiation imaging detection systems  

International Nuclear Information System (INIS)

A nuclear imaging system includes an analog signal processor which features analog data derandomization for minimizing data loss due to pulse pile-up. A scintillation detector provides a sequence of analog data pulses to the signal processor, the data pulses characterizing the energy level and situs of respective radiation events striking the detector. The signal processor includes sets of novel peak detectors and of sample and hold circuits which are serially connected and are operated to derandomize or space the sequence of analog data pulses so that the system can process pulses corresponding to photopeak events occurring only 1.5 microseconds apart. The analog data pulses are stored in analog pulse form in the peak detectors and are selectively transferred into the sample and hold circuitry from which they are transferred to the display mechanism. The signal processor is multiplexed with several data input channels for accommodating dual isotope operation. A control unit is provided which controls the data processing cycle according to a predetermined processing time, or according to signals from external system apparatus. The control unit provides automatic resetting for assurance that the signal processor does not become locked into an inoperative, nondata processing state. The novel peak detectors are controlled by the control unit and feature input biasing for increased detection sensitivity, proportional dumping for discharging the stored peak value at a rate proportional to the value of the stored peak, and selective input data gating so that only the peak containing portion of the input signal is input into the detector. 28 claims, 10 figures

40

Radiation detection system  

International Nuclear Information System (INIS)

A circuit is disclosed that detects radiation transients and provides a clamping signal in response to each transient. The clamping signal is present from the time the transient rises above a given threshold level and for a known duration thereafter. The system includes radiation sensors, a blocking oscillator that generates a pulse in response to each sensor signal, and an output pulse duration control circuit. The oscillator pulses are fed simultaneously to the output pulse duration control circuit and to an OR gate, the output of which comprises the system output. The output pulse duration is controlled by the time required to magnetize a magnetic core to saturation in first one direction and then the other

41

Radiation protection, measurements and methods  

International Nuclear Information System (INIS)

The introductory lectures discuss subjects such as radiation protection principles and appropriate measuring techniques; methods, quantities and units in radiation protection measurement; technical equipment; national and international radiation protection standards. The papers presented at the various sessions deal with: Dosimetry of external radiation (27 papers); Working environment monitoring and emission monitoring (21 contributions); Environmental monitoring (19 papers); Incorporation monitoring (9 papers); Detection limits (4 papers); Non-ionizing radiation, measurement of body dose and biological dosimetry (10 papers). All 94 contributions (lectures, compacts and posters) are retrievable as separate records. (HP)

42

Detection and identification of radiation induced hydrocarbons in meets with the use of gas chromatography as one of methods for the detection of irradiated food  

International Nuclear Information System (INIS)

Results of the determination of the content of radiation induced hydrocarbons in meat samples (chicken, pork, beef) as well as proportion between the concentration of individual hydrocarbons in relation to the content of fatty acids in a given product are presented. The measurements have been done with the use of a Perkin Elmer model 8700 gas chromatograph equipped with a FID detector. The present study is a preliminary work on the implementation of a routine method for the detection of irradiation in foods that contain fats. (author)

43

Radiation Detection Computational Benchmark Scenarios  

Energy Technology Data Exchange (ETDEWEB)

Modeling forms an important component of radiation detection development, allowing for testing of new detector designs, evaluation of existing equipment against a wide variety of potential threat sources, and assessing operation performance of radiation detection systems. This can, however, result in large and complex scenarios which are time consuming to model. A variety of approaches to radiation transport modeling exist with complementary strengths and weaknesses for different problems. This variety of approaches, and the development of promising new tools (such as ORNL’s ADVANTG) which combine benefits of multiple approaches, illustrates the need for a means of evaluating or comparing different techniques for radiation detection problems. This report presents a set of 9 benchmark problems for comparing different types of radiation transport calculations, identifying appropriate tools for classes of problems, and testing and guiding the development of new methods. The benchmarks were drawn primarily from existing or previous calculations with a preference for scenarios which include experimental data, or otherwise have results with a high level of confidence, are non-sensitive, and represent problem sets of interest to NA-22. From a technical perspective, the benchmarks were chosen to span a range of difficulty and to include gamma transport, neutron transport, or both and represent different important physical processes and a range of sensitivity to angular or energy fidelity. Following benchmark identification, existing information about geometry, measurements, and previous calculations were assembled. Monte Carlo results (MCNP decks) were reviewed or created and re-run in order to attain accurate computational times and to verify agreement with experimental data, when present. Benchmark information was then conveyed to ORNL in order to guide testing and development of hybrid calculations. The results of those ADVANTG calculations were then sent to PNNL for compilation. This is a report describing the details of the selected Benchmarks and results from various transport codes.

Shaver, Mark W.; Casella, Andrew M.; Wittman, Richard S.; McDonald, Ben S.

2013-09-24

44

Evaluation methods for detecting changes in beam output and energy in radiation beams from high-energy linear accelerators  

International Nuclear Information System (INIS)

There is need for simple methods for checking consistency of beam outputs and energy in linear accelerators used for radiotherapy. A method was designed by the department using perspex phantom with which the dosimetric data of two medical linear accelerators (Clinac 600 CD, Clinac 2300 CD) were evaluated over a period of 30 months. The efficacy of methods followed was checked. Routine beam consistency checks were designed for photon beams with 15 cm/5 cm depth ionizations in perspex phantom and variable depth combinations for electron beams. Calculated ionization ratios were compared with measured values to show their significance. The dose/MU for all radiation beams was maintained within 2% accuracy over the period of 30 months. Clinac 600 CD machine showed decreasing trend of cGy/MU, while Clinac 2300 CD showed increasing trend of cGy/MU over a period, which needed tuning of monitor chamber two times each. Tuning of output to achieve standard value was carried out once, for all electron energies when the output dose/MU exceeded 3%. During one week (June 2005), there were slight changes in electron energy detected using the ratio method, which did not recur anytime afterwards. The methods designed are adequate to find the consistency in the beam output and energies in the radiotherapy linacs. (author)

45

Evaluation methods for detecting changes in beam output and energy in radiation beams from high-energy linear accelerators.  

Science.gov (United States)

There is need for simple methods for checking consistency of beam outputs and energy in linear accelerators used for radiotherapy. A method was designed by the department using perspex phantom with which the dosimetric data of two medical linear accelerators (Clinac 600 CD, Clinac 2300 CD) were evaluated over a period of 30 months. The efficacy of methods followed was checked. Routine beam consistency checks were designed for photon beams with 15 cm/ 5 cm depth ionizations in perspex phantom and variable depth combinations for electron beams. Calculated ionization ratios were compared with measured values to show their significance. The dose/MU for all radiation beams was maintained within 2% accuracy over the period of 30 months. Clinac 600 CD machine showed decreasing trend of cGy/MU, while Clinac 2300 CD showed increasing trend of cGy/MU over a period, which needed tuning of monitor chamber two times each. Tuning of output to achieve standard value was carried out once, for all electron energies when the output dose/MU exceeded 3%. During one week (June 2005), there were slight changes in electron energy detected using the ratio method, which did not recur anytime afterwards. The methods designed are adequate to find the consistency in the beam output and energies in the radiotherapy linacs. PMID:21157527

Ravichandran, R; Binukumar, J P; Davis, C A; Krishnamurthy, K; Sivakumar, S S

2007-07-01

46

Evaluation methods for detecting changes in beam output and energy in radiation beams from high-energy linear accelerators  

Directory of Open Access Journals (Sweden)

Full Text Available There is need for simple methods for checking consistency of beam outputs and energy in linear accelerators used for radiotherapy. A method was designed by the department using perspex phantom with which the dosimetric data of two medical linear accelerators (Clinac 600 CD, Clinac 2300 CD were evaluated over a period of 30 months. The efficacy of methods followed was checked. Routine beam consistency checks were designed for photon beams with 15 cm/ 5 cm depth ionizations in perspex phantom and variable depth combinations for electron beams. Calculated ionization ratios were compared with measured values to show their significance. The dose/MU for all radiation beams was maintained within 2% accuracy over the period of 30 months. Clinac 600 CD machine showed decreasing trend of cGy/MU, while Clinac 2300 CD showed increasing trend of cGy/MU over a period, which needed tuning of monitor chamber two times each. Tuning of output to achieve standard value was carried out once, for all electron energies when the output dose/MU exceeded 3%. During one week (June 2005, there were slight changes in electron energy detected using the ratio method, which did not recur anytime afterwards. The methods designed are adequate to find the consistency in the beam output and energies in the radiotherapy linacs.

Ravichandran R

2007-01-01

47

Principles of radiation detection  

International Nuclear Information System (INIS)

After a short description of the ionizing radiations and their interactions with matter, the properties and functions of radiation detector systems in general and of the scintillation and semiconductor detectors in particular are presented. Figs and tabs

48

Apparatus and method for examining a blood vessel of interest using radiation detected outside the body  

International Nuclear Information System (INIS)

Stenotic atherosclerotic lesions of the coronary arteries are detected by injecting a number of particulate signal sources such as positron-emitting particles (e.g. gallium 68) into the blood of a subject to determine the velocity of blood flow through the coronary vessels. The particles are tracked in three dimensions whenever they appear in the region of the heart by means of high-resolution high-speed gamma detectors that surround the chest. These recordings of particle position as a function of time are analyzed, and the velocity of blood as it flows through the coronary artery is measured by timing the transit of the particle. From the accumulated data of multiple particle transits through the coronary circulation, a three-dimensional representation of the lumen of the coronary arterial system is constructed

49

Measurement and detection of radiation  

CERN Document Server

This is an update of the standard textbook for the field of radiation measurement. It includes illustrative examples and new problems. The research and applications of nuclear instrumentation have grown substantially since publication of the previous editions. With the miniaturization of equipment, increased speed of electronic components, and more sophisticated software, radiation detection systems are now more productively used in many disciplines, including nuclear nonproliferation, homeland security, and nuclear medicine. Continuing in the tradition of its bestselling predecessors, "Measurement and Detection of Radiation, Third Edition" illustrates the fundamentals of nuclear interactions and radiation detection with a multitude of examples and problems. It offers a clearly written, accessible introduction to nuclear instrumentation concepts. The following are new to the third edition: a new chapter on the latest applications of radiation detection, covering nuclear medicine, dosimetry, health physics, no...

Tsoulfanidis, Nicholas

2011-01-01

50

Electronics for radiation detection  

CERN Document Server

Addresses the developments in the design of semiconductor detectors and integrated circuits, in the context of medical imaging using ionizing radiation. This book explains how circuits for radiation are built, focusing on practical information about how they are being used, rather than mathematical details.

2011-01-01

51

Determination of radiation-induced hydrocarbons in processed food and complex lipid matrices. A new solid phase extraction (SPE) method for detection of irradiated components in food  

International Nuclear Information System (INIS)

Detection of irradiated components in processed food with complex lipid matrices can be affected by two problems. First, the processed food may contain only a small amount of the irradiated component, and the radiation-induced hydrocarbons may be diluted throughout the lipid matrix of the whole food. Second, in complex lipid matrices, the detection of prior irradiation is often disturbed by fat-associated compounds. In these cases, common solid phase extraction (SPE) Florisil clean-up alone is inadequate in the detection of prior irradiation. Subsequent SPE argentation chromatography of the Florisil eluate allows the measurement of small amounts of irradiated lipid-containing ingredients in processed food as well as the detection of prior irradiation in complex lipid matrices such as paprika and chilli. SPE argetation chromatography is the first method available for the selective enrichment of radiation-specific hydrocarbons from even complex lipid matrices, thus enabling the detection of irradiation does as low as 0.025 kGy. Furthermore, by using radiation-induced hydrocarbons in the detection of prior irradiation of paprika and chilli powder, a second independent method, the first being measurement of thermoluminescence, is available for the analysis of these matrices. Such analysis could be achieved by using this highly sensitive, cheap and easy to perform combined SPE Florisil/argentation chromatography method, without the need for sophisticated techniques like SFE-GC/MS or LC-GC/MS, so that highly sensitive detection of prior irradiation colud be performed in almost every laboratory

52

Aerial Radiation Detection  

Energy Technology Data Exchange (ETDEWEB)

An airborne system designed for the detection of radioactive sources on the soil surface from an aircraft normally senses gamma rays emitted by the source. Gamma rays have the longest path length (least attenuation) through the air of any of the common radioactive emissions and will thus permit source detection at large distances. A secondary benefit from gamma rays detection if that nearly all radioactive isotopes can be identified by the spectrum of gammas emitted. Major gaseous emissions from fuel processing plants emit gammas that may be detected and identified. Some types of special nuclear material also emit neutrons which are also useful for detection at a distance.

W. M. Quam

1999-09-30

53

Aerial Radiation Detection  

International Nuclear Information System (INIS)

An airborne system designed for the detection of radioactive sources on the soil surface from an aircraft normally senses gamma rays emitted by the source. Gamma rays have the longest path length (least attenuation) through the air of any of the common radioactive emissions and will thus permit source detection at large distances. A secondary benefit from gamma rays detection if that nearly all radioactive isotopes can be identified by the spectrum of gammas emitted. Major gaseous emissions from fuel processing plants emit gammas that may be detected and identified. Some types of special nuclear material also emit neutrons which are also useful for detection at a distance

54

Bayesian detection analysis for radiation exposure, II  

International Nuclear Information System (INIS)

The application of Bayesian statistical methods to the interpretation of radiation protection measurements has been discussed in the first article of the series in 1993. The present work continues that discussion and (1) provides sharper definitions of detection categories POSITIVE, SMALL, and NDA; (2) describes an empirical method for determining the prior probability distribution; (3) describes a sequential re-measurement strategy; and (4) defines detection limits LMDA (minimum detectable amount) and LMMA (maximum missed amount) based on the Bayesian detection criterion POSITIVE. It is shown that the Bayesian detection criterion is always more stringent than the classical criterion. (author)

55

Detection of nuclear radiations  

International Nuclear Information System (INIS)

A summary of the lectures about the ordinary detectors of nuclear radiations explained by the author in the courses of Nuclear Engineering held at the J.E.N. up to the date of publication is given. Those lectures are considered to be a necessary introduction to Nuclear Instrumentation and Applied Electronics to Nuclear Engineering so it has been intended to underline those characteristics of radiation detectors that must be taken in consideration in choosing or designing the electronic equipment associated to them in order to take advantage of each detector possibilities. (Author)

56

Detection of nuclear radiations  

International Nuclear Information System (INIS)

A summary of the lectures about the ordinary detectors of nuclear radiations given by the author in the Courses of Introduction to Nuclear Engineering held at the JEN up to the date of publication is given. Those lectures are considered to be a necessary introduction to Nuclear Instrumentation and Applied electronics to Nuclear Engineering so it has been intent to underline those characteristics of radiation detectors that must be taken in consideration in choosing or designing the electronic equipment associated to them in order to take advantage of each detector possibilities. (Author) 8 refs

57

Radiation detection and measurement  

International Nuclear Information System (INIS)

The fundamental mechanism for the operation of a radiation detector is dissipation of the energy of a charged particle in a suitable medium. Useful energy dissipation is principally by two processes: ionisation and scintillation. The electrostatics of pulse formation for the ionisation chamber is discussed in detail

58

Detection of gravitational radiation  

Energy Technology Data Exchange (ETDEWEB)

In this report the main contributions presented at the named symposium are collected. These concern astrophysical sources of gravitational radiation, ultracryogenic gravitational wave experiments, read out and data analysis of gravitational wave antennas, cryogenic aspects of large mass cooling to mK temperatures, and metallurgical and engineering aspects of large Cu structure manufacturing. (HSI).

Holten, J.W. van [ed.

1994-12-31

59

Radiation Detection for Homeland Security Applications  

Science.gov (United States)

In the past twenty years or so, there have been significant changes in the strategy and applications for homeland security. Recently there have been significant at deterring and interdicting terrorists and associated organizations. This is a shift in the normal paradigm of deterrence and surveillance of a nation and the `conventional' methods of warfare to the `unconventional' means that terrorist organizations resort to. With that shift comes the responsibility to monitor international borders for weapons of mass destruction, including radiological weapons. As a result, countries around the world are deploying radiation detection instrumentation to interdict the illegal shipment of radioactive material crossing international borders. These efforts include deployments at land, rail, air, and sea ports of entry in the US and in European and Asian countries. Radioactive signatures of concern include radiation dispersal devices (RDD), nuclear warheads, and special nuclear material (SNM). Radiation portal monitors (RPMs) are used as the main screening tool for vehicles and cargo at borders, supplemented by handheld detectors, personal radiation detectors, and x-ray imaging systems. This talk will present an overview of radiation detection equipment with emphasis on radiation portal monitors. In the US, the deployment of radiation detection equipment is being coordinated by the Domestic Nuclear Detection Office within the Department of Homeland Security, and a brief summary of the program will be covered. Challenges with current generation systems will be discussed as well as areas of investigation and opportunities for improvements. The next generation of radiation portal monitors is being produced under the Advanced Spectroscopic Portal program and will be available for deployment in the near future. Additional technologies, from commercially available to experimental, that provide additional information for radiation screening, such as density imaging equipment, will be reviewed. Opportunities for further research and development to improve the current equipment and methodologies for radiation detection for the important task of homeland security will be the final topic to be discussed.

Ely, James

2008-05-01

60

Cherenkov radiation used in detection of some beta emitters  

International Nuclear Information System (INIS)

The prerequisites of the formation of Cherenkov radiation in the passage of beta radiation through a medium are described and the possibility of detecting some beta emitters in an aqueous medium by a liquid scintillation spectrometer is shown. The advantages and disadvantages of the detection method are presented and its parameters (detection efficiency, background, selectivity) are compared with those of commonly used methods. (author)

61

Radiation detection system  

Science.gov (United States)

A preamplifier circuit for processing a signal provided by a radiation detector includes a transimpedance amplifier coupled to receive a current signal from a detector and generate a voltage signal at its output. A second amplification stage has an input coupled to an output of the transimpedance amplifier for providing an amplified voltage signal. Detector electronics include a preamplifier circuit having a first and second transimpedance amplifier coupled to receive a current signal from a first and second location on a detector, respectively, and generate a first and second voltage signal at respective outputs. A second amplification stage has an input coupled to an output of the transimpedance amplifiers for amplifying the first and said second voltage signals to provide first and second amplified voltage signals. A differential output stage is coupled to the second amplification stage for receiving the first and second amplified voltage signals and providing a pair of outputs from each of the first and second amplified voltage signals. Read out circuitry has an input coupled to receive both of the pair of outputs, the read out circuitry having structure for processing each of the pair of outputs, and providing a single digital output having a time-stamp therefrom.

Riedel, Richard A. (Knoxville, TN); Wintenberg, Alan L. (Knoxville, TN); Clonts, Lloyd G. (Knoxville, TN); Cooper, Ronald G. (Oak Ridge, TN)

2012-02-14

62

A method for the quantitative determination of synchrotron radiation X-ray spectra for absolute XRF-trace element detection  

International Nuclear Information System (INIS)

In the X-ray energy range the principal calculability of the synchrotron radiation flux-density and polarisation spectra is limited in practice by the fact that the essential parameters of vertical electron beam cross-section and -divergence are not well known due to instabilities that can occur at higher stored currents. This difficulty in calculating absolute X-ray spectra from first principles can be overcome by a semi-empirical method: By a polarisation measurement over a large energy range, effective electron beam parameters can be defined that lead to reliable calculated X-ray flux-density and polarisation spectra. With these data experimental scattering spectra could be verified extremely well on an absolute scale over an energy range of 2 keV to 35 keV. This is a necessary premise for the development of a method of absolute mass determination from XRF-spectra with synchrotron radiation excitation. (orig.)

63

Detection of food treated with ionizing radiation  

International Nuclear Information System (INIS)

Treatment of food with ionizing energy-'food irradiation'- is finally becoming reality in many countries. The benefits include an improvement in food hygiene, spoilage reduction and extension of shelf-life. Although properly irradiated food is safe and wholesome, consumers should be able to make their own free choice between irradiated and non-irradiated food. For this purpose labelling is indispensable. In order to check compliance with existing regulations, detection of radiation treatment by analysing the food itself is highly desirable. Significant progress has been made in recent years in developing analytical detection methods utilizing changes in food originating from the radiation treatment

64

Detection of radiation-induced translocations in A-bomb survivors by fluorescence in situ hybridization (FISH) method  

International Nuclear Information System (INIS)

The present paper describes the results of a collaborative study by RERF, LINL and UCSF on an analysis of the utility of fluorescence in situ hybridization (FISH) with whole-chromosome probes (chromosomes 1, 2 and 4) for measurement of the frequencies of chromosomal translocations that have persisted for decades in the peripheral blood lymphocytes of atomic bomb survivors. In this study, attempts have been made to investigate whether the translocation frequencies measured using FISH agree well with the translocation frequencies measured using both G-banding and conventional Giemsa staining analyses, the latter two techniques of which have been accepted as standard cytogenetic procedures. Sample subjects under study include 20 Hiroshima A-bomb survivors, consisting of 2 distally exposed survivors in the 0-Gy group, and 18 proximally exposed survivors with estimated DS86 kerma ranging from 0.5 to 5.0 Gy. Our preliminary results of measurement of translocations using FISH on A-bomb survivors have indicated that the FISH technique is a useful biological assay system for rapid and accurate detection of induced translocations, and thus for quantification of previous acute exposures to ionizing radiation. Translocation analysis using FISH can also be utilized to assess the level of acute radiation exposure independent of time between exposure and cytogenetic analysis. (author)

65

Multigrid contact detection method.  

Science.gov (United States)

Contact detection is a general problem of many physical simulations. This work presents a O(N) multigrid method for general contact detection problems (MGCD). The multigrid idea is integrated with contact detection problems. Both the time complexity and memory consumption of the MGCD are O(N). Unlike other methods, whose efficiencies are influenced strongly by the object size distribution, the performance of MGCD is insensitive to the object size distribution. We compare the MGCD with the no binary search (NBS) method and the multilevel boxing method in three dimensions for both time complexity and memory consumption. For objects with similar size, the MGCD is as good as the NBS method, both of which outperform the multilevel boxing method regarding memory consumption. For objects with diverse size, the MGCD outperform both the NBS method and the multilevel boxing method. We use the MGCD to solve the contact detection problem for a granular simulation system based on the discrete element method. From this granular simulation, we get the density property of monosize packing and binary packing with size ratio equal to 10. The packing density for monosize particles is 0.636. For binary packing with size ratio equal to 10, when the number of small particles is 300 times as the number of big particles, the maximal packing density 0.824 is achieved. PMID:17500829

He, Kejing; Dong, Shoubin; Zhou, Zhaoyao

2007-03-01

66

Optimizing a method for detection of hepatitis A virus in shellfish and study the effect of gamma radiation on the viral genome  

International Nuclear Information System (INIS)

Our work was aimed at detecting the hepatitis A virus (HAV) in bivalve mollusc collected from five shellfish harvesting areas and from a coastal region in Tunisia using RT-Nested-PCR and studying the effect of gamma radiation on HAV genome. Two methods used to recover HAV from mollusc flesh and two methods of extraction of virus RNA were compared in order to determine the most sensitive method. Glycine extraction and extraction of virus RNA using proteinase K were more convenient and then used in this study for detection of HAV in shellfish. The results of molecular analyses: RT-Nested-PCR using primers targeted at the P1 region revealed that 28 % of the samples were positive for HAV. Doses of gamma irradiation ranging between 5 to 30 kGy were used to study the effect of this radiation on HAV genome after the contamination of mollusc flesh with suspension of HAV (derived from stool specimens). HAV specific genomic band was observed for doses between 5 to 20 kGy. We didn't detect HAV genome with doses 25 and 30 kGy. (Author)

67

Application of the microbiological method DEFT/APC to detect minimally processed vegetables treated with gamma radiation  

International Nuclear Information System (INIS)

Marketing of minimally processed vegetables (MPV) are gaining impetus due to its convenience, freshness and apparent health effect. However, minimal processing does not reduce pathogenic microorganisms to safe levels. Food irradiation is used to extend the shelf life and to inactivate food-borne pathogens. In combination with minimal processing it could improve safety and quality of MPV. A microbiological screening method based on the use of direct epifluorescent filter technique (DEFT) and aerobic plate count (APC) has been established for the detection of irradiated foodstuffs. The aim of this study was to evaluate the applicability of this technique in detecting MPV irradiation. Samples from retail markets were irradiated with 0.5 and 1.0 kGy using a 60Co facility. In general, with a dose increment, DEFT counts remained similar independent of the irradiation while APC counts decreased gradually. The difference of the two counts gradually increased with dose increment in all samples. It could be suggested that a DEFT/APC difference over 2.0 log would be a criteria to judge if a MPV was treated by irradiation. The DEFT/APC method could be used satisfactorily as a screening method for indicating irradiation processing.

68

Leak detection method  

International Nuclear Information System (INIS)

This invention provides a method for removing nuclear fuel elements from a fabrication building while at the same time testing the fuel elements for leaks without releasing contaminants from the fabrication building or from the fuel elements. The vacuum source used, leak detecting mechanism and fuel element fabrication building are specified to withstand environmental hazards. (UK)

69

Application of the microbiological method DEFT/APC and DNA comet assay to detect ionizing radiation processing of minimally processed vegetables  

International Nuclear Information System (INIS)

Marketing of minimally processed vegetables (MPV) are gaining impetus due to its convenience, freshness and apparent healthy. However, minimal processing does not reduce pathogenic microorganisms to safe levels. Food irradiation is used to extend the shelf life and inactivation of food-borne pathogens, Its combination with minimal processing could improve the safety and quality of MPV. Two different food irradiation detection methods, a biological, the DEFT/APC, and another biochemical, the DNA Comet Assay were applied to MPV in order to test its applicability to detect irradiation treatment. DEFT/APC is a microbiological screening method based on the use of the direct epi fluorescent filter technique (DEFT) and the aerobic plate count (APC). DNA Comet Assay detects DNA damage due to ionizing radiation. Samples of lettuce, chard, watercress, dandelion, kale, chicory, spinach, cabbage from retail market were irradiated O.5 kGy and 1.0 kGy using a 60 Co facility. Irradiation treatment guaranteed at least 2 log cycle reduction for aerobic and psychotropic microorganisms. In general, with increasing radiation doses, DEFT counts remained similar independent of irradiation processing while APC counts decreased gradually. The difference of the two counts gradually increased with dose increment in all samples. It could be suggested that a DEFT/APC difference over 2.0 log would be a criteria to judge if a MPV was treated by irradiation. DNA Comet Assay allowed distinguishing non-irradiated samples from irradiated ones, which showed different types of comets owing to DNA fragmentation. Both DEFT/APC method and DNA Comet Assay would be satisfactorily used as a screening method for indicating irradiation processing. (author)

70

Exoplanet Detection: Transit Method  

Science.gov (United States)

The Exoplanet Detection: Transit Method model simulates the detection of exoplanets by using the transit method of detecting exoplanets. In this method, the light curve from a star, and how it changes over time due to exoplanet transits, is observed and then analyzed. In this simulation the exoplanet orbits the star (sun-sized) in circular motion via Kepler's third law.  When the exoplanet passes in front of the star (transits), it blocks part of the starlight. This decrease in starlight is shown on the graph.  If the exoplanet is close enough to the central star, and has sufficient reflectivity, or albedo, it can reflect enough of the starlight to be seen on the light curve. In the simulation the star-exoplanet system is shown as seen from Earth (edge on view) but magnified greatly, and with the star and planet sizes not shown to the scale of the orbit. The radius of the central star (relative to the radius of Sun),semi-major axis of the exoplanet (in AU), radius of the exoplanet (relative to the radius of Jupiter), the exoplanet's albedo (reflectivity), and the inclination of the system relative to Earth can be changed. The simulation uses Java 3D, if installed, to render the view the star and exoplanet. If Java 3D is not installed, the simulation will default to simple 3D using Java.

Belloni, Mario

2010-06-29

71

Comparative study using Monte Carlo methods of the radiation detection efficiency of LSO, LuAP, GSO and YAP scintillators for use in positron emission imaging (PET)  

International Nuclear Information System (INIS)

The radiation detection efficiency of four scintillators employed, or designed to be employed, in positron emission imaging (PET) was evaluated as a function of the crystal thickness by applying Monte Carlo Methods. The scintillators studied were the LuSiO5 (LSO), LuAlO3 (LuAP), Gd2SiO5 (GSO) and the YAlO3 (YAP). Crystal thicknesses ranged from 0 to 50 mm. The study was performed via a previously generated photon transport Monte Carlo code. All photon track and energy histories were recorded and the energy transferred or absorbed in the scintillator medium was calculated together with the energy redistributed and retransported as secondary characteristic fluorescence radiation. Various parameters were calculated e.g. the fraction of the incident photon energy absorbed, transmitted or redistributed as fluorescence radiation, the scatter to primary ratio, the photon and energy distribution within each scintillator block etc. As being most significant, the fraction of the incident photon energy absorbed was found to increase with increasing crystal thickness tending to form a plateau above the 30 mm thickness. For LSO, LuAP, GSO and YAP scintillators, respectively, this fraction had the value of 44.8, 36.9 and 45.7% at the 10 mm thickness and 96.4, 93.2 and 96.9% at the 50 mm thickness. Within the plateau area approximately (57-59)% (59-63)% (52-63)% and (58-61)% of this fraction was due to scattered and reabsorbed rtion was due to scattered and reabsorbed radiation for the LSO, GSO, YAP and LuAP scintillators, respectively. In all cases, a negligible fraction (<0.1%) of the absorbed energy was found to escape the crystal as fluorescence radiation

72

Management of the baseline shift using a new and simple method for respiratory-gated radiation therapy: Detectability and effectiveness of a flexible monitoring system  

Energy Technology Data Exchange (ETDEWEB)

Purpose: In respiratory-gated radiation therapy, a baseline shift decreases the accuracy of target coverage and organs at risk (OAR) sparing. The effectiveness of audio-feedback and audio-visual feedback in correcting the baseline shift in the breathing pattern of the patient has been demonstrated previously. However, the baseline shift derived from the intrafraction motion of the patient's body cannot be corrected by these methods. In the present study, the authors designed and developed a simple and flexible system. Methods: The system consisted of a web camera and a computer running our in-house software. The in-house software was adapted to template matching and also to no preimage processing. The system was capable of monitoring the baseline shift in the intrafraction motion of the patient's body. Another marker box was used to monitor the baseline shift due to the flexible setups required of a marker box for gated signals. The system accuracy was evaluated by employing a respiratory motion phantom and was found to be within AAPM Task Group 142 tolerance (positional accuracy <2 mm and temporal accuracy <100 ms) for respiratory-gated radiation therapy. Additionally, the effectiveness of this flexible and independent system in gated treatment was investigated in healthy volunteers, in terms of the results from the differences in the baseline shift detectable between the marker positions, which the authors evaluated statistically. Results: The movement of the marker on the sternum [1.599 {+-} 0.622 mm (1 SD)] was substantially decreased as compared with the abdomen [6.547 {+-} 0.962 mm (1 SD)]. Additionally, in all of the volunteers, the baseline shifts for the sternum [-0.136 {+-} 0.868 (2 SD)] were in better agreement with the nominal baseline shifts than was the case for the abdomen [-0.722 {+-} 1.56 mm (2 SD)]. The baseline shifts could be accurately measured and detected using the monitoring system, which could acquire the movement of the marker on the sternum. The baseline shift-monitoring system with the displacement-based methods for highly accurate respiratory-gated treatments should be used to make most of the displacement-based gating methods. Conclusions: The advent of intensity modulated radiation therapy and volumetric modulated radiation therapy facilitates margin reduction for the planning target volumes and the OARs, but highly accurate irradiation is needed to achieve target coverage and OAR sparing with a small margin. The baseline shifts can affect treatment not only with the respiratory gating system but also without the system. Our system can manage the baseline shift and also enables treatment irradiation to be undertaken with high accuracy.

Tachibana, Hidenobu; Kitamura, Nozomi; Ito, Yasushi; Kawai, Daisuke; Nakajima, Masaru; Tsuda, Akihisa; Shiizuka, Hisao [Department of Radiation Oncology, Cancer Institute Hospital of the Japanese Foundation of Cancer Research, Tokyo 1358550 (Japan); Department of Nuclear Engineering and Management, Graduate School of Engineering, University of Tokyo, Tokyo 1130032 (Japan); Department of Information Design, Kogakuin University, Tokyo 1638677 (Japan)

2011-07-15

73

Management of the baseline shift using a new and simple method for respiratory-gated radiation therapy: Detectability and effectiveness of a flexible monitoring system  

International Nuclear Information System (INIS)

Purpose: In respiratory-gated radiation therapy, a baseline shift decreases the accuracy of target coverage and organs at risk (OAR) sparing. The effectiveness of audio-feedback and audio-visual feedback in correcting the baseline shift in the breathing pattern of the patient has been demonstrated previously. However, the baseline shift derived from the intrafraction motion of the patient's body cannot be corrected by these methods. In the present study, the authors designed and developed a simple and flexible system. Methods: The system consisted of a web camera and a computer running our in-house software. The in-house software was adapted to template matching and also to no preimage processing. The system was capable of monitoring the baseline shift in the intrafraction motion of the patient's body. Another marker box was used to monitor the baseline shift due to the flexible setups required of a marker box for gated signals. The system accuracy was evaluated by employing a respiratory motion phantom and was found to be within AAPM Task Group 142 tolerance (positional accuracy <2 mm and temporal accuracy <100 ms) for respiratory-gated radiation therapy. Additionally, the effectiveness of this flexible and independent system in gated treatment was investigated in healthy volunteers, in terms of the results from the differences in the baseline shift detectable between the marker positions, which the authors evaluated statistically. Results: The movement of the markercally. Results: The movement of the marker on the sternum [1.599 ± 0.622 mm (1 SD)] was substantially decreased as compared with the abdomen [6.547 ± 0.962 mm (1 SD)]. Additionally, in all of the volunteers, the baseline shifts for the sternum [-0.136 ± 0.868 (2 SD)] were in better agreement with the nominal baseline shifts than was the case for the abdomen [-0.722 ± 1.56 mm (2 SD)]. The baseline shifts could be accurately measured and detected using the monitoring system, which could acquire the movement of the marker on the sternum. The baseline shift-monitoring system with the displacement-based methods for highly accurate respiratory-gated treatments should be used to make most of the displacement-based gating methods. Conclusions: The advent of intensity modulated radiation therapy and volumetric modulated radiation therapy facilitates margin reduction for the planning target volumes and the OARs, but highly accurate irradiation is needed to achieve target coverage and OAR sparing with a small margin. The baseline shifts can affect treatment not only with the respiratory gating system but also without the system. Our system can manage the baseline shift and also enables treatment irradiation to be undertaken with high accuracy.

74

Detection methods of irradiated foodstuffs  

International Nuclear Information System (INIS)

Full text: Food irradiation has, in certain circumstances, an important role to play both in promoting food safety and in reducing food losses. The safety and availability of nutritious food are essential components of primary health care. WHO actively encourages the proper use of food irradiation in the fight against foodborne diseases and food losses. To this end, it collaborates closely with FAO and IAEA. Food irradiation can have a number of beneficial effects, including delay of ripening and prevention of sprouting; control of insects, parasites, helminths, pathogenic and spoilage bacteria, moulds and yeasts; and sterilization, which enables commodities to be stored unrefrigerated for long periods. The 1990s witnessed a significant advancement in food irradiation processing. As a result, progress has been made in commercialization of the technology, culminating in greater international trade in irradiated foods and the implementation of differing regulations relating to its use in many countries. Codex General Standard for Irradiated Foodstuffs and Recommended International Code of Practice for the Operation of Irradiation Facilities Used for the Treatment of Foods regulate food irradiation at international level. At European Union level there are in power Directive 1999/2/EC and Directive1999/3/EC. Every particular country has also its own regulations regarding food irradiation. In Romania, since 2002 the Norms Regarding Foodstuffs and Food Ingredients Treated b Foodstuffs and Food Ingredients Treated by Ionizing Radiation are in power. These Norms are in fact the Romanian equivalent law of the European Directives 1999/2/EC and 1999/3/EC. The greater international trade in irradiated foods has led to the demand by consumers that irradiated food should be clearly labeled as such and that methods capable of differentiating between irradiated and nonirradiated products should be available. Thus a practical basis was sought to allow consumers to exercise a free choice as to which food they purchase. If a food is marketed as irradiated or if irradiated goods are sold without the appropriate labeling, then detection tests should be able to prove the authenticity of the product. For the moment in Romania there is not any food control laboratory able to detect irradiated foodstuffs. The Technological Irradiation Department coordinates and co finances a research project aimed to establish the first Laboratory of Irradiated Foodstuffs Detection. The detection methods studied in this project are the ESR methods (for cellulose EN 1787/2000, bone EN 1786/1996 and crystalline sugar EN 13708/2003), the TL method (EN 1788/2001), the PSL method (EN 13751/2002) and the DNA Comet Assay method (EN 13784/2001). The above detection methods will be applied on various foodstuffs such: garlic, onion, potatoes, rice, beans, wheat, maize, pistachio, sunflower seeds, raisins, figs, strawberries, chicken, beef, fish, pepper, paprika, thyme, laurel and mushrooms. As an example of the application of a detection method there are presented the ESR spectra of irradiated and nonirradiated paprika acquired according to ESR detection method for irradiated foodstuffs containing cellulose. First of all it can be noticed that the intensity of the signal of cellulose is much higher for the irradiated sample than that for the nonirradiated one and second that appear two radiation specific signals symmetrical to the cellulose signal. These two radiation specific signals prove the irradiation treatment of paprika. (author)

75

Radiation Detection at Borders for Homeland Security  

Science.gov (United States)

Countries around the world are deploying radiation detection instrumentation to interdict the illegal shipment of radioactive material crossing international borders at land, rail, air, and sea ports of entry. These efforts include deployments in the US and a number of European and Asian countries by governments and international agencies. Items of concern include radiation dispersal devices (RDD), nuclear warheads, and special nuclear material (SNM). Radiation portal monitors (RPMs) are used as the main screening tool for vehicles and cargo at borders, supplemented by handheld detectors, personal radiation detectors, and x-ray imaging systems. Some cargo contains naturally occurring radioactive material (NORM) that triggers "nuisance" alarms in RPMs at these border crossings. Individuals treated with medical radiopharmaceuticals also produce nuisance alarms and can produce cross-talk between adjacent lanes of a multi-lane deployment. The operational impact of nuisance alarms can be significant at border crossings. Methods have been developed for reducing this impact without negatively affecting the requirements for interdiction of radioactive materials of interest. Plastic scintillator material is commonly used in RPMs for the detection of gamma rays from radioactive material, primarily due to the efficiency per unit cost compared to other detection materials. The resolution and lack of full-energy peaks in the plastic scintillator material prohibits detailed spectroscopy. However, the limited spectroscopic information from plastic scintillator can be exploited to provide some discrimination. Energy-based algorithms used in RPMs can effectively exploit the crude energy information available from a plastic scintillator to distinguish some NORM. Whenever NORM cargo limits the level of the alarm threshold, energy-based algorithms produce significantly better detection probabilities for small SNM sources than gross-count algorithms. This presentation discusses experience with RPMs for interdiction of radioactive materials at borders.

Kouzes, Richard

2004-05-01

76

Deterministic methods in radiation transport  

Energy Technology Data Exchange (ETDEWEB)

The Seminar on Deterministic Methods in Radiation Transport was held February 4--5, 1992, in Oak Ridge, Tennessee. Eleven presentations were made and the full papers are published in this report, along with three that were submitted but not given orally. These papers represent a good overview of the state of the art in the deterministic solution of radiation transport problems for a variety of applications of current interest to the Radiation Shielding Information Center user community.

Rice, A.F.; Roussin, R.W. (eds.)

1992-06-01

77

Deterministic methods in radiation transport  

International Nuclear Information System (INIS)

The Seminar on Deterministic Methods in Radiation Transport was held February 4--5, 1992, in Oak Ridge, Tennessee. Eleven presentations were made and the full papers are published in this report, along with three that were submitted but not given orally. These papers represent a good overview of the state of the art in the deterministic solution of radiation transport problems for a variety of applications of current interest to the Radiation Shielding Information Center user community

78

Method of locating radiation detectors  

International Nuclear Information System (INIS)

Purpose: To avoid direct contact between a detector and radioactive liquid wastes upon on-line measurement of radio activity for radioactive liquid wastes. Method: A by-pass is provided to a pipe through which liquid wastes flow thus making laminar flow of the liquid wastes. A detection portion is provided to the laminar flow portion. In the detection portion, are formed an upper chamber and a lower chamber in contaction to the laminar flow. The upper chamber is filled with a fluid having a specific gravity lower than that of the liquid wastes and insoluble to the liquid wastes, for example, benzene or cyclohexane, which is contacted to the laminar flow. A radiation detector is provided in the above fluid of a low specific gravity. This can prevent the direct contaction between the detector and the liquid wastes and avoid the deposition of oils and scales contained in the liquid wastes to the detector. The above liquid of the lower specific gravity is circulated and cleaned by a pump. In the lower chamber of the pipe, a fluid having a specific gravity higher than that of the liquid wastes and insoluble to the liquid wastes is filled for removing the precipitating substances. (Ikeda, J.)

79

Radiation Detection Center on the Front Lines  

International Nuclear Information System (INIS)

Many of today's radiation detection tools were developed in the 1960s. For years, the Laboratory's expertise in radiation detection resided mostly within its nuclear test program. When nuclear testing was halted in the 1990s, many of Livermore's radiation detection experts were dispersed to other parts of the Laboratory, including the directorates of Chemistry and Materials Science (CMS); Physics and Advanced Technologies (PAT); Defense and Nuclear Technologies (DNT); and Nonproliferation, Arms Control, and International Security (NAI). The RDC-- was formed to maximize the benefit of radiation detection technologies being developed in 15 to 20 research and development (R and D) programs. These efforts involve more than 200 Laboratory employees across eight directorates, in areas that range from electronics to computer simulations. The RDC's primary focus is the detection, identification, and analysis of nuclear materials and weapons. A newly formed outreach program within the RDC-- is responsible for conducting radiation detection workshops and seminars across the country and for coordinating university student internships. Simon Labov, director of the RDC, says, ''Virtually all of the Laboratory's programs use radiation detection devices in some way. For example, DNT uses radiation detection to create radiographs for their work in stockpile stewardship and in diagnosing explosives; CMS uses it to develop technology for advancing the detection, diagnosis, and treatmening the detection, diagnosis, and treatment of cancer; and the Energy and Environment Directorate uses radiation detection in the Marshall Islands to monitor the aftermath of nuclear testing in the Pacific. In the future, the National Ignition Facility will use radiation detection to probe laser targets and study shock dynamics.''

80

Evaluation methods for detecting changes in beam output and energy in radiation beams from high-energy linear accelerators  

OpenAIRE

There is need for simple methods for checking consistency of beam outputs and energy in linear accelerators used for radiotherapy. A method was designed by the department using perspex phantom with which the dosimetric data of two medical linear accelerators (Clinac 600 CD, Clinac 2300 CD) were evaluated over a period of 30 months. The efficacy of methods followed was checked. Routine beam consistency checks were designed for photon beams with 15 cm/ 5 cm depth ionizations in perspex phantom ...

Ravichandran R; Binukumar J; Davis C.; Krishnamurthy K; Sivakumar S

2007-01-01

81

Leak detection method  

International Nuclear Information System (INIS)

Purpose: To perform satisfactory automatic scram for reactors by reliable leak detection in LMFBR type reactors. Method: A plurality of leak detectors each given with a channel number are provided to equipments and pipeways in a nuclear power plant. A digital computer receives the outputs from the leak detectors and judges, if the predetermined number of detectors are actuated, whether the plurality of actuated detectors are at the positions adjacent to each other. If they are at the adjacent positions, the digital computer judges that liquid leaks occur. That is, the digital computer judges the degree of significance for the locations of the leak detectors from their channel numbers, and issues a plant stop signal where the leak is judged and if the degree of significance is high. (Horiuchi, T.)

82

Radiation dosimetry instrumentation and methods  

CERN Document Server

Radiation dosimetry has made great progress in the last decade, mainly because radiation therapy is much more widely used. Since the first edition, many new developments have been made in the basic methods for dosimetry, i.e. ionization chambers, TLD, chemical dosimeters, and photographic films. Radiation Dosimetry: Instrumentation and Methods, Second Edition brings to the reader these latest developments. Written at a high level for medical physicists, engineers, and advanced dosimetrists, it concentrates only on evolvement during the last decade, relying on the first edition to provide the basics.

Shani, Gad

2000-01-01

83

CLOUD DETECTION METHODS – A REVIEW  

Directory of Open Access Journals (Sweden)

Full Text Available Cloud detection is a one of the most important processes in weather predication and regional planning. Detection of clouds helps to improve the efficiency in study of climatic changes. Different methods are in use and most of the methods have its own implementation issues. This paper explains widely used cloud detection methods and its challenges.

B.RAMESH

2013-04-01

84

Main Achievements 2003-2004 - Interdisciplinary Research - Radiation detection methods for health, earth and environmental sciences - High precision silicon detectors  

International Nuclear Information System (INIS)

In the IFJ, research on high precision silicon detectors for medical applications began in the late eighties, following the experience and international contacts acquired by particle physicists who had worked on silicon vertex detectors in high energy physics experiments since the early eighties. Among others, the IFJ team has specialized in the Data Acquisition Systems. In the years 2001-2004 the team participated in the project ''Silicon Ultra fast Cameras for electron and gamma sources in Medical Applications'' (SUCIMA), financed by an EC grant of the 5th FP. The main goal of SUCIMA was the development of an advanced imaging technique of extended radioactive sources for medical applications. The SUCIMA cameras, based on the Monolithic Active Pixel Sensors in CMOS technology (MAPS), are designed to optimise radiation safety conditions during brachytherapy and hadron therapy treatments and to improve the accuracy of both therapies. The IFJ team was responsible for developing the fast DAQ systems for three types of silicon sensors: MAPS (basic development), silicon strip detectors (backup solution) and SOI test structures (R and D for innovative silicon detectors) and for the dedicated Graphical User Interfaces for data visualization. The whole readout chains consisting of the dedicated hybrids, repeaters and imager board have been designed, built and tested for each type of sensors. The SUCIMA imager is the heart of this fast electronics and performs real-f this fast electronics and performs real-time data analysis and compression. The module is based on VIRTEX II - the most advanced XILINX FPGA chip

85

Detection of nuclear warheads by radiation  

International Nuclear Information System (INIS)

Attention has been focused on the technique to utilize nuclear radiation as a promising means of detecting nuclear warheads loaded on board warships or bombers. Such a method will be very useful as a practical measure of verification necessary to the conclusion of any treaty for nuclear disarmament which is under negotiation between USA and USSR. It may also be used by Japan to ascertain whether the foreign warships calling Japanese ports carry nuclear weapons or not. Recently, the Federation of American Scientists and the Committee of Soviet Scientists for Peace and against Nuclear Threat have advanced the Cooperative Verification Project about such a detection technique on a nongovernmental basis. In July, 1989, they conducted for the first time the joint experiment on warhead detection in the Black Sea under the full cooperation of Soviet Navy, and succeeded in obtaining a number of interesting results. In this report, the main results are given, and some remarks on the possibility of extending the method to the remote monitoring of the clandestine introduction of nuclear weapons by foreign vessels are made. The comparison of the various methods and the experiment in the Black Sea are reported. (K.I.)

86

Development of detection/analysis for radiation induced mutations using new DNA analyzing techniques. Construction of effective probe and primer, and their detection method  

Energy Technology Data Exchange (ETDEWEB)

An investigation was made on the genome structure of 28 S rDNA in the respect of radiation-induced double strand cleavages in DNA. It has been reported that there is an insertion of retro-transposon in some rDNA. There is a possibility that rDNA may have a specific structure composed of several regions of different sensitivities to radiation exposure. Hence, the structure and the functions of such regions were investigated. This region was as long as 2.5 Mb in length and divided into inserted type and un-inserted one. FISH showed that the inserted regions are composed of mini-clusters and the structure was high-ordered. A new primer was constructed so as to provide PCR products of about 5 Kb in length. When the DNA was exposed to {gamma}-ray ({sup 60}Co and {sup 137}Cs), the amount of PCR products was dose-dependently increased up to 10 Gy and the increase was 15-20 % at the dose. Therefore, it was suggested that PCR amplification was enhanced because of the destruction of higher-ordered structure caused by radiation exposure. The sensitivity of some DNA region to {sup 60}Co or {sup 137}Cs exposure was different from that of other regions in respect of the formation of double strand cleavage. Therefore, it was thought that such high-ordered genome region could be distinguishable from other regions with the differences in radiation sensitivity of genome DNA. (M.N.)

Maekawa, Hideaki; Tsuchida, Kozo; Hashido, Kazuo; Takada, Naoko; Kameoka, Yosuke; Hirata, Makoto [National Insto. of Infectious Disease, Tokyo (Japan)

2000-02-01

87

Indirect detection of radiation sources through direct detection of radiolysis products  

Science.gov (United States)

A system for indirectly detecting a radiation source by directly detecting radiolytic products. The radiation source emits radiation and the radiation produces the radiolytic products. A fluid is positioned to receive the radiation from the radiation source. When the fluid is irradiated, radiolytic products are produced. By directly detecting the radiolytic products, the radiation source is detected.

Farmer, Joseph C. (Tracy, CA); Fischer, Larry E. (Los Gatos, CA); Felter, Thomas E. (Livermore, CA)

2010-04-20

88

Radiation, ionization, and detection in nuclear medicine  

Energy Technology Data Exchange (ETDEWEB)

Up-to-date information on a wide range of topics relating to radiation, ionization, and detection in nuclear medicine. In-depth coverage of basic radiophysics relating to diagnosis and therapy. Extensive discussion of instrumentation and radiation detectors. Detailed information on mathematical modelling of radiation detectors. Although our understanding of cancer has improved, the disease continues to be a leading cause of death across the world. The good news is that the recent technological developments in radiotherapy, radionuclide diagnostics and therapy, digital imaging systems, and detection technology have raised hope that cancer will in the future be combatted more efficiently and effectively. For this goal to be achieved, however, safe use of radionuclides and detailed knowledge of radiation sources are essential. Radiation, Ionization, and Detection in Nuclear Medicine addresses these subjects and related issues very clearly and elaborately and will serve as the definitive source of detailed information in the field. Individual chapters cover fundamental aspects of nuclear radiation, including dose and energy, sources, and shielding; the detection and measurement of radiation exposure, with detailed information on mathematical modelling; medical imaging; the different types of radiation detector and their working principles; basic principles of and experimental techniques for deposition of scintillating materials; device fabrication; the optical and electrical behaviors of radiation detectors; and the instrumentation used in nuclear medicine and its application. The book will be an invaluable source of information for academia, industry, practitioners, and researchers.

Gupta, Tapan K. [Radiation Monitoring Devices Research, Nuclear Medicine, Watertown, MA (United States)

2013-08-01

89

Physics and engineering of radiation detection  

CERN Document Server

Physics and Engineering of Radiation Detection presents an overview of basic physics of radiation and its applications and covers the origins and properties of different kinds of ionizing radiation, their detection and measurement, and the procedures used to protect people and the environment from their potentially harmful effects. Covering both the basic physics of radiation and its applications, it will provide an up-to-date and coherent account of the origins and properties of the different kinds of ionizing radiation, and their detection and measurement. This book will illustrate the basic physical principles with an abundance of practical, worked-out examples, numerical problems, real world applications, and data, including biological effects, radon, risk assessment, and statistics.

Ahmed, Syed Naeem

2007-01-01

90

On the ?-photon detection processes and the statistics of radiation  

International Nuclear Information System (INIS)

The problem of detection of ?-photons is treated in the cases of photoelectric and Compton effects. In both cases the probability of detecting a ?-photon is found proportional to the first-order correlation function of the e.m. field. The statistical properties of the ?-radiation can therefore be determined through the methods developed in quantum optics

91

In-Ground Radiation Detection  

Energy Technology Data Exchange (ETDEWEB)

Vertically oriented radiation detectors may not provide sufficient screening in rail or aviation applications. Railcars can be heavily shielded on the sides, reducing the sensitivity of vertically mounted monitors. For aviation, the distance required for wingspan clearance reduces a vertical detector’s coverage of the fuselage. To surmount these, and other, challenging operational and sensitivity issues, we have investigated the use of in-ground radiation detectors. (PIET-43741-TM-605).

McCormick, Kathleen R.; Stromswold, David C.; Woodring, Mitchell L.; Ely, James H.; Siciliano, Edward R.; Caggiano, Joseph A.; Hensley, Walter K.

2006-10-29

92

Current trends in ionizing radiation detection  

Energy Technology Data Exchange (ETDEWEB)

Ionizing radiation is a both a natural and man-made phenomena that plays a major role in contemporary applications. The detection of this radiation has evolved over the past several decades from simple observations to precise measurements in space, time, and energy, even in harsh environmental conditions. In this paper, we present a snapshot of the current state-of-the-art in radiation measurement technology, highlighting the major applications and detector developments.

Wehe, David K. [University of Michigan, Ann Arbor (United States)

2006-06-15

93

Current trends in ionizing radiation detection  

International Nuclear Information System (INIS)

Ionizing radiation is a both a natural and man-made phenomena that plays a major role in contemporary applications. The detection of this radiation has evolved over the past several decades from simple observations to precise measurements in space, time, and energy, even in harsh environmental conditions. In this paper, we present a snapshot of the current state-of-the-art in radiation measurement technology, highlighting the major applications and detector developments

94

Device for detecting ionizing radiation  

International Nuclear Information System (INIS)

The present invention relates to ionizing radiation sensors, and , more particularly, to semiconductor spectrometers with thermoelectric cooling, and can most advantageously be used in mineral raw material exploration and evaluation under field conditions. The spectrometer comprises a vacuum chamber with an entrance window for passing the radiation therethrough. The vacuum chamber accommodates a thermoelectric cooler formed by a set of peltier elements. A heat conducting plate is mounted on the cold side of the thermoelectric cooler, and its hot side is provided with a radiator. Mounted on the heat conducting plate are sets of peltier elements, integral with the thermoelectric cooler and independent of one another. The peltier elements of these sets are stacked so as to develop the minimum temperature conditions on one set carrying a semiconductor detector and to provide the maximum refrigeration capacity conditions on the other set provided with the field-effect transistor mounted thereon

95

Special Frisbees Detect Ultraviolet Radiation  

Science.gov (United States)

This experiment helps students understand that ultraviolet (UV) radiation is present in natural outdoor light and that the intensity of the light varies with season and time of day. After completing this activity, students will be able to demonstrate that UV radiation can be blocked or filtered by various substances. The page contains detailed background material, learning goals, alignment to national standards, grade level/time, details on materials and preparation, procedure, suggested extensions, assessment ideas, modifications for alternative learners, special notes, and an example lab report format.

2007-12-12

96

Radiation detection and measurement student solutions manual  

CERN Document Server

This is the resource that engineers turn to in the study of radiation detection. The fourth edition takes into account the technical developments that continue to enhance the instruments and techniques available for the detection and spectroscopy of ionizing radiation. New coverage is presented on ROC curves, micropattern gas detectors, new sensors for scintillation light, and the excess noise factor. Revised discussions are also included on TLDs and cryogenic spectrometers, radiation backgrounds, and the VME standard. Engineers will gain a strong understanding of the field with this updated book.

Wehe, David K

2012-01-01

97

Detection and measurement of ionizing radiation  

International Nuclear Information System (INIS)

All detection or measurement of radiation rests in the possibility of recognizing the interactions of radiation with matter. When radiation passes through any kind of material medium, all or a portion of its energy is transferred to this medium. This transferred energy produces an effect in the medium. In principle, the detection of radiation is based on the appearance and the observation of this effect. In theory, all of the effects produced by radiation may be used in detecting it: in practice, the effects most commonly employed are: (1) ionization of gases (gas detectors), or of some chemical substance which is transformed by radiation (photographic or chemical dosimeters); (2) excitations in scintillators or semiconductors (scintillation counters, semiconductor counters); (3) creation of structural defects through the passage of radiation (transparent thermoluminescent and radioluminescent detectors); and (4) raising of the temperature (calorimeters). This study evaluates in detail, instruments based on the ionization of gases and the production of luminescence. In addition, the authors summarize instruments which depend on other forms of interaction, used in radiation medicine and hygiene (radiology, nuclear medicine)

98

Silicon solid state devices and radiation detection  

CERN Document Server

This book addresses the fundamental principles of interaction between radiation and matter, the principles of working and the operation of particle detectors based on silicon solid state devices. It covers a broad scope with respect to the fields of application of radiation detectors based on silicon solid state devices from low to high energy physics experiments including in outer space and in the medical environment. This book covers stateof- the-art detection techniques in the use of radiation detectors based on silicon solid state devices and their readout electronics, including the latest developments on pixelated silicon radiation detector and their application.

Leroy, Claude

2012-01-01

99

Radiation Detection, Response and Recovery  

International Nuclear Information System (INIS)

Mission: Strengthen the capabilities of partner countries to deter, detect, and interdict illicit trafficking of special nuclear and other radioactive materials at international border crossings including airports, seaports, and other points of entry/exit. Strategy: Develop cooperative efforts to mitigate the risk of illicit trafficking through: • Search, detection, and identification of nuclear and other radioactive materials; • Development of response procedures and capabilities; • Deterrence of future trafficking in illicit nuclear and nuclear-related materials. Goal: Deliver an effective and sustainable global capability to deter, detect, and interdict illicit trafficking in special nuclear and other radioactive materials

100

Gravitational Radiation Detection with Laser Interferometry  

CERN Document Server

Gravitational-wave detection has been pursued relentlessly for over 40 years. With the imminent operation of a new generation of laser interferometers, it is expected that detections will become a common occurrence. The research into more ambitious detectors promises to allow the field to move beyond detection and into the realm of precision science using gravitational radiation. In this article, I review the state of the art for the detectors and describe an outlook for the coming decades.

Adhikari, Rana X

2013-01-01

101

HPV Detection Methods  

OpenAIRE

Given the causal relation between a persistent high-risk human papillomavirus (hrHPV) infection and the development of high-grade cervical intraepithelial neoplasia (CIN) and cervical cancer, hrHPV testing has been advocated in addition to cytology for the detection of clinically relevant cervical lesions. HrHPV testing is thought to improve cervical screening algorithms, the management of women with cytologically equivocal smears, and the management of women treated for high grade CIN. In th...

Brink, Antoinette A. T. P.; Snijders, Peter J. F.; Meijer, Chris J. L. M.

2007-01-01

102

Electrets for beta radiation detection  

International Nuclear Information System (INIS)

Electret dosimetry has been reviewed by Gross. A cylindrical electret ionization-chamber type dosimeter has been studied for X and gamma rays and neutrons. The principle of the dosimeter is electret charge compensation due to ionization in the chamber volume. Electret ionization chambers can be designed with one or more electrets and in various shapes. This study is concerned with a simple system, similar to a cylindrical ionization chamber (sensitive volume: 3,5 cm3) using teflon electrets. Aluminum and lucite were used as wall-materials. Other experiences were performed using chambers without wall, i.e., without defined sensitive volume. The teflon electrets were obtained by Corona discharge in the gas surrounding them. The measurement of the electret charge was made by induction using a co-axial insulated metal chamber connected to an electrometer Keithley 610C. By measuring the charge before and after irradiation it is possible to obtain a calibration curve: charge (Q) versus absorbed dose (D) for the dosimeter. The irradiation setup used was the Beta Secondary Standard System of IPEN calibration laboratory with four beta sources: 90Sr90Y (74 and 1850 MBq), 204Tl (18,5 MBq) and 147Pm (518 MBq). In some cases a 85Kr source was also used. The electrets were tested in different radiation field geometries: electret axis parallel and perpendicular to the field. In conclusion, depending on the wall material and radiation field geometry, the teflon electret detector can be used for different dose interval determinations, using beta radiation

103

Method for detecting solidifacation in a mixed phase container  

International Nuclear Information System (INIS)

The invention deals with a method for the detection of chunks of solid material in a mixed-phase container. The solidification is detected by observing a decrease in the amount of radiation reaching a detector, after passing through a radiation path through a portion of the volume of the container

104

? radiation detection with ultra thin thermoluminescent samples  

International Nuclear Information System (INIS)

The possibility of ? radiation detection using ultra thin thermoluminescent (TL) CaSO4:Dy/Teflon dosimeters (UT-CaSO4:Dy) was investigated. The ? irradiations were carried out with 90Sr-90Y, 204Tl and 147Pm sources. The individual reproducibility, linearity, dependence on ? absorbed dose rate, optical fading, angular and energy dependence of the samples were studied. Transmission factors for different thicknesses of tissue equivalent material were obtained for the TL detectors, using the three available ? sources. The results obtained show the usefulness of UT-CaSO4:Dy in ? radiation detection

105

Simple method to demonstrate radiation-inducible radiation resistance in microbial cells.  

OpenAIRE

A simple method for detection of radiation-inducible radiation resistance was developed by irradiating aliquots (0.01 ml) of cell suspension on agar plates. Part of each experimental plate was subjected to an induction treatment, and subsequent radiation resistance was compared with that of untreated cells on the same plate. The UV radiation resistance of a Micrococcus sp. was increased approximately 1.6 times by an induction treatment. This simple procedure of irradiating cells in a "fixed" ...

Tan, S. T.; Maxcy, R. B.

1986-01-01

106

Space Radiation Transport Methods Development  

Science.gov (United States)

Early space radiation shield code development relied on Monte Carlo methods for proton, neutron and pion transport and made important contributions to the space program. More recently Monte Carlo code LAHET has been upgraded to include high-energy multiple-charged light ions for GCR simulations and continues to be expanded in capability. To compensate for low computational efficiency, Monte Carlo methods have resorted to restricted one-dimensional problems leading to imperfect representations of appropriate boundary conditions. Even so, intensive computational requirements resulted and shield evaluation was made near the end of the design process and resolving shielding issues usually had a negative impact on the design. We evaluate the implications of these common one-dimensional assumptions on the evaluation of the Shuttle internal radiation field. Improved spacecraft shield design requires early entry of radiation constraints into the design process to maximize performance and minimize costs. As a result, we have been investigating high-speed computational procedures to allow shield analysis from the preliminary design concepts to the final design. In particular, we will discuss the progress towards a full three-dimensional and computationally efficient deterministic code for which the current HZETRN evaluates the lowest order asymptotic term. HZETRN is the first deterministic solution to the Boltzmann equation allowing field mapping within the International Space Station (ISS) in tens of minutes using standard Finite Element Method (FEM) geometry common to engineering design practice enabling development of integrated multidisciplinary design optimization methods. A single ray trace in ISS FEM geometry requires 14 milliseconds and severely limits application of Monte Carlo methods to such engineering models. A potential means of improving the Monte Carlo efficiency in coupling to spacecraft geometry is given in terms of reconfigurable computing and could be utilized in the final design as verification of the deterministic method optimized design.

Wilson, J.; Tripathi, R.; Qualls, G.; Cucinotta, F.; Prael, R.; Norbury, J.

107

Mobile Radiation Detection System against Nuclear Terrorism  

International Nuclear Information System (INIS)

After the September 11th, 2001, terrorist attacks in the USA, the discovery of Al-Qaeda's experimentation to build dirty bomb and the death of a former officer of the Russian Federal Security Service from Po-210- induced acute radiation exposure, the threats relating to nuclear and radioactive materials have become a matter of increased international concern. Detection of illicit transport and trafficking of nuclear and radioactive materials is necessary for prevention of nuclear terrorism, since failure in detection might lead to catastrophic results. A mobile radiation detection system plays an important role in preventing the potential dangers posed by illicit transport and trafficking of such dangerous materials because it can monitor the suspicious vehicle at place beyond terrorist's expectation which makes intentionally a detour about the portal monitor deployed at seaports, airports, and key traffic checkpoints. The mobile radiation detection system using one NaI, two plastic scintillation, and two He-3 detectors has been developed. This paper describes the developed mobile radiation detection system and experimental results for its performance assessment

108

Energy detection method and apparatus  

International Nuclear Information System (INIS)

A method is described of detecting neutrinos comprising the steps of irradiating a material with the neutrinos to cause coherent stimulated emission of radiant energy fields in the material in response to the material being irradiated by the neutrinos, and detecting the coherent radiant energy fields

109

Analytical detection methods for irradiated foods  

International Nuclear Information System (INIS)

The present publication is a review of scientific literature on the analytical identification of foods treated with ionizing radiation and the quantitative determination of absorbed dose of radiation. Because of the extremely low level of chemical changes resulting from irradiation or because of the lack of specificity to irradiation of any chemical changes, a few methods of quantitative determination of absorbed dose have shown promise until now. On the other hand, the present review has identified several possible methods, which could be used, following further research and testing, for the identification of irradiated foods. An IAEA Co-ordinated Research Programme on Analytical Detection Methods for Irradiation Treatment of Food ('ADMIT'), established in 1990, is currently investigating many of the methods cited in the present document. Refs and tab

110

Composite scintillators for detection of ionizing radiation  

Science.gov (United States)

Applicant's present invention is a composite scintillator having enhanced transparency for detecting ionizing radiation comprising a material having optical transparency wherein said material comprises nano-sized objects having a size in at least one dimension that is less than the wavelength of light emitted by the composite scintillator wherein the composite scintillator is designed to have selected properties suitable for a particular application.

Dai, Sheng (Knoxville, TN) [Knoxville, TN; Stephan, Andrew Curtis (Knoxville, TN) [Knoxville, TN; Brown, Suree S. (Knoxville, TN) [Knoxville, TN; Wallace, Steven A. (Knoxville, TN) [Knoxville, TN; Rondinone, Adam J [Knoxville, TN

2010-12-28

111

Detection and measurement of nuclear radiations  

International Nuclear Information System (INIS)

In this chapter the theory and applications of the various instruments used to measure and detect nuclear radiations are presented. Much of the theory described is used in subsequent chapters to explain the operation of imaging devices used in nuclear medicine

112

Separation space for isotachophoresis with radiation detection  

International Nuclear Information System (INIS)

The facility allows to detect radiation in an arbitrary point without disturbing the process of separation and to detect the state and/or place of complete separation of components. It also allows the measurement of the moving zone boundary. The separation space consists of electrode areas with auxiliary equipment interconnected by means of a capillary on a support structure and of a radiation source and a detector. The support structure with electrode areas with auxiliaries is pivoted with regard to the detector and is fitted with a capillary arranged to a ring and a capillary pressure ring defining the slot for the radiation source rays passing through the capillary to the detector. The axis of rotation and the axis of the ring mounting are identical. (J.P.)

113

Waveshifters and Scintillators for Ionizing Radiation Detection  

Energy Technology Data Exchange (ETDEWEB)

Scintillation and waveshifter materials have been developed for the detection of ionizing radiation in an STTR program between Ludlum Measurements, Inc. and the University of Notre Dame. Several new waveshifter materials have been developed which are comparable in efficiency and faster in fluorescence decay than the standard material Y11 (K27) used in particle physics for several decades. Additionally, new scintillation materials useful for fiber tracking have been developed which have been compared to 3HF. Lastly, work was done on developing liquid scintillators and paint-on scintillators and waveshifters for high radiation environments.

B.Baumgaugh; J.Bishop; D.Karmgard; J.Marchant; M.McKenna; R.Ruchti; M.Vigneault; L.Hernandez; C.Hurlbut

2007-12-11

114

Waveshifters and Scintillators for Ionizing Radiation Detection  

International Nuclear Information System (INIS)

Scintillation and waveshifter materials have been developed for the detection of ionizing radiation in an STTR program between Ludlum Measurements, Inc. and the University of Notre Dame. Several new waveshifter materials have been developed which are comparable in efficiency and faster in fluorescence decay than the standard material Y11 (K27) used in particle physics for several decades. Additionally, new scintillation materials useful for fiber tracking have been developed which have been compared to 3HF. Lastly, work was done on developing liquid scintillators and paint-on scintillators and waveshifters for high radiation environments

115

Radiation techniques for detection of explosives  

International Nuclear Information System (INIS)

The detection of explosive material in airport baggage requires a device that can quickly detect a small amount of explosives with a high success rate and a low positive false alarm rate. The device should be able to handle carry-on as well as checked baggage and should provide indications that are independent of the geometric configuration of the material. The mass density of an explosive compound is relatively high. Also, explosives have high nitrogen and oxygen densities. Most detection techniques exploit the nitrogen-rich nature of explosives. Although few materials have such a high nitrogen density, some plastics, clothing materials and narcotics have also high nitrogen content. In order to distinguish such innocuous materials from explosives, one needs to detect the presence of other elements, particularly oxygen. The measurement of high oxygen density in the inspected object, together with a high nitrogen density, provides a strong indication that the object contains an explosive material. This is the minimum requirement for unambiguous determination of the presence of explosives. An additional measurement will decrease the degree of ambiguity and increase the reliability of the system. A number of radiation based techniques have been developed, or are being considered for the detection of explosives. This paper reviews some of these techniques, based on the type and mode of interaction of the radiation employed

116

Neutron Radiation System for Explosives Detection in Cargo Containers  

International Nuclear Information System (INIS)

A measuring inspection system created in VNIIA and intended for active interrogation of cargo containers to detect explosives is presented. The system is based on (a) the 14 MeV 'tagged' neutron method in combination with nanosecond neutron analysis, and (b) the detection of characteristic secondary gamma-radiation from the reaction of inelastic neutron scattering on sample objects. Experimental results for the detection of an explosive simulator - melamine (C3H6N6) are presented for different container loadings (wood, iron) and for different arrangements of the explosive simulator. (author)

117

Method and apparatus for measuring electromagnetic radiation  

Science.gov (United States)

An apparatus and method are described in which the capacitance of a semiconductor junction subjected to an electromagnetic radiation field is utilized to indicate the intensity or strength of the radiation.

Been, J. F. (inventor)

1973-01-01

118

Adaptable radiation monitoring system and method  

Science.gov (United States)

A portable radioactive-material detection system capable of detecting radioactive sources moving at high speeds. The system has at least one radiation detector capable of detecting gamma-radiation and coupled to an MCA capable of collecting spectral data in very small time bins of less than about 150 msec. A computer processor is connected to the MCA for determining from the spectral data if a triggering event has occurred. Spectral data is stored on a data storage device, and a power source supplies power to the detection system. Various configurations of the detection system may be adaptably arranged for various radiation detection scenarios. In a preferred embodiment, the computer processor operates as a server which receives spectral data from other networked detection systems, and communicates the collected data to a central data reporting system.

Archer, Daniel E. (Livermore, CA); Beauchamp, Brock R. (San Ramon, CA); Mauger, G. Joseph (Livermore, CA); Nelson, Karl E. (Livermore, CA); Mercer, Michael B. (Manteca, CA); Pletcher, David C. (Sacramento, CA); Riot, Vincent J. (Berkeley, CA); Schek, James L. (Tracy, CA); Knapp, David A. (Livermore, CA)

2006-06-20

119

Plastic scintillator-based radiation detector for mobile radiation detection system against nuclear/radiological terrorism  

Science.gov (United States)

Illicit trafficking of nuclear or radioactive materials has become a serious world wide problem. Due to operational constraints of radiation detection system for such nuclear security application, a radiation detector with large effective area is needed to maximize its sensitivity. This paper suggests a new method of using plastic scintillation detector as a cost-effective mobile radiation detection system. Monte Carlo simulation code, MCNPX, has been used to analyze spectral distribution available from the plastic detector and to derive algorithmic process with a view to discriminating targeted sources from ambient background radiation. Theoretical results in present work showed that the targeted sources which might be used for nuclear/radiological terrorism could be discriminated from Nationally Occurring Radioactive Material (NORM) or background.

Kwak, Sung-Woo; Yoo, Ho-Sik; Jang, Sung Soon; Kim, Jung Soo; Yoon, Wan-Ki; Jun, In Sub; Kim, Kwang Hyun

2009-06-01

120

Radiation detection technology assessment program (RADTAP)  

International Nuclear Information System (INIS)

The U.S. Customs Service and the U.S. Department of Energy (DOE) conducted a technical and operational assessment of gamma ray radiation detection equipment during the period May 5-16, 1997 at a testing facility in North Carolina. The effort was entitled, ''Radiation Detection Technology Assessment Program (RADTAP)'', and was conducted for the purpose of assessing the applicability, sensitivity and robustness of a diverse suite of gamma ray detection and identification equipment for possible use by Customs and other law enforcement agencies. Thirteen companies entered 25 instruments into the assessment program. All detection equipment entered had to exhibit a minimum sensitivity of 20 micro-R per hour (background included) from a Cesium-137 point source. Isotope identifying spectrometers entered were man portable and operable at room temperature with read-out that could be interpreted by non-technical personnel. Radioactive sources used in the assessment included special nuclear material, industrial and health isotopes. Evaluators included Customs inspectors and technical experts from DOE and Customs. No conclusions or recommendations were issued based on the quantitative and qualitative test results, however, the results of the program provided law enforcement agencies with the necessary data to select equipment that best meets their operational needs and budgets. (author)

121

New method to detect radiotherapy gamma field  

International Nuclear Information System (INIS)

Full text: This paper describes a novel method, which allows one to measure the intensity distribution of energetic gamma radiation field, used typically in radiation therapy. Traditionally, measurements are based on a detector system of one or more ionization chambers or an array of semiconductor diodes, which are working in the so called current mode. Therefore, in these methods the spatial resolution is limited by the size of the individual chamber- or diode unit and varies typically from one to five centimeters. The improvement in the resolution leads one to decrease the unit size, increase their amount and, consequently, the electronics (amplifiers etc.), because each detection unit needs its own channel. Better resolution is getting more important question together with the generalization of the Intensity Modulated Radiation Therapy (IMRT) but, unfortunately, the improvement in spatial resolution can only be achieved by increasing considerably the total expenses. Our detection method offers a solution to improve the spatial resolution with very low extra costs. It relies on a position sensitive avalanche counter (PSAC), which owns good position resolution and detection efficiency abilities for heavy ions. Due to the extremely high intensity and low ionization properties of gamma radiation, direct monitoring of gamma field with PSAC has not been possible so far. Therefore, a converter with an adequate cross section to photo fission reactions is used to convert the high intensity gamma field to a 'low' intensity field of heavy fission fragments, which then have the intensity distribution similar to the original gammas. The fragments have an excellent capability to ionize the chamber gas and the discrete pulses can easily be sorted out from the background. By this way the resolution of one millimeter in a typical total gamma field area and with a very simple applied electronics can be achieved. The chamber is also very robust against the radiation damages, which is not the case e.g. with the semiconductor diodes. The converter and wire thicknesses, wire voltages and gas pressure are the parameters, which allow one to optimize the operation of the detector for the certain accelerator conditions. In the final paper we will introduce our detection system and its construction in more detail. We also give the first results about the tests we have carried out in the laboratory and in a hospital accelerator and compare the resolutions to the ones existing in the recent detectors. (author)

122

Development of the Neutron Radiation Detection Technology  

International Nuclear Information System (INIS)

This research is carried out by focusing on the following four matters. First, the neutron sensor with the best suited sensitivity which can detect neutron dose was designed and manufactured. Comparing the experimental results with the numerical simulation results, the optimal neutron sensory device which consists of individualized PIN diode was developed. Second, on the basis of the capacity which was gotten from the measurements and evaluations on dosimetry module at the KCCH neutron tests, the neutron test module was accurately designed with efficient detecting algorithm. Third, the classification on the neutron detecting signal was performed. On the basis of measurement and analysis of the KCCH neutron test results, the linearity to the neutron sensitivity was evaluated and the signal classification was researched for the final test at NIST Fourth, the characteristics of radiation hardening on neutron dosimetry circuit was evaluated to improve the reliability of dosimetry circuit as high dose of neutron detonates

123

Methodical principles of radiation safety  

International Nuclear Information System (INIS)

The fundamental principles of radiation safety and the radiation protection are discussing in this book, which is addressed to persons working in the field of radiation safety and, due to their professional obligations, are in contact with ionizing radiations. The authors discuss the specific effects of ionizing radiation on human subjects, as well as the criteria for evaluation and control of the radiation risk, irradiation of peoples being in age of reproduction, planned increase of professional irradiation and accidentally increased professional irradiation (radiation hazards), as well as irradiation of individuals and population groups and irradiation of the total population. All questions treated in this book are interpreted according to the most recent concepts published in the last document of the ICRS. (M.Kh.)

124

Bubble Radiation Detection: Current and Future Capability  

International Nuclear Information System (INIS)

Despite a number of noteworthy achievements in other fields, superheated droplet detectors (SDDs) and bubble chambers (BCs) have not been used for nuclear nonproliferation and arms control. This report examines these two radiation-detection technologies in detail and answers the question of how they can be or should be ''adapted'' for use in national security applications. These technologies involve closely related approaches to radiation detection in which an energetic charged particle deposits sufficient energy to initiate the process of bubble nucleation in a superheated fluid. These detectors offer complete gamma-ray insensitivity when used to detect neutrons. They also provide controllable neutron-energy thresholds and excellent position resolution. SDDs are extraordinarily simple and inexpensive. BCs offer the promise of very high efficiency (?75%). A notable drawback for both technologies is temperature sensitivity. As a result of this problem, the temperature must be controlled whenever high accuracy is required, or harsh environmental conditions are encountered. The primary findings of this work are listed and briefly summarized below: (1) SDDs are ready to function as electronics-free neutron detectors on demand for arms-control applications. The elimination of electronics at the weapon's location greatly eases the negotiability of radiation-detection technologies in general. (2) As a result of their high efficiency and sharp energy threshold, current BCs are almost ready for use in the development of a next-generation active assay system. Development of an instrument based on appropriately safe materials is warranted. (3) Both kinds of bubble detectors are ready for use whenever very high gamma-ray fields must be confronted. Spent fuel MPC and A is a good example where this need presents itself. (4) Both kinds of bubble detectors have the potential to function as low-cost replacements for conventional neutron detectors such as 3He tubes. For SDDs, this requires finding some way to get boron into the detector. For BCs, this requires finding operating conditions permitting a high duty cycle

125

Survey of Anomaly Detection Methods  

Energy Technology Data Exchange (ETDEWEB)

This survey defines the problem of anomaly detection and provides an overview of existing methods. The methods are categorized into two general classes: generative and discriminative. A generative approach involves building a model that represents the joint distribution of the input features and the output labels of system behavior (e.g., normal or anomalous) then applies the model to formulate a decision rule for detecting anomalies. On the other hand, a discriminative approach aims directly to find the decision rule, with the smallest error rate, that distinguishes between normal and anomalous behavior. For each approach, we will give an overview of popular techniques and provide references to state-of-the-art applications.

Ng, B

2006-10-12

126

Detecting solar chameleons through radiation pressure  

CERN Document Server

Light scalar fields can drive accelerated expansion of the universe. Hence, scalars are obvious dark energy candidates. To make these models compatible with test of General Relativity in the solar system and fifth force searches on earth, one needs to screen them. One possibility is the chameleon mechanism, which renders an effective mass depending on the local energy density. If chameleons exist, they can be produced in the sun and detected on earth through their radiation pressure. We calculate the solar chameleon spectrum and the sensitivity of an experiment to be carried out at CAST, CERN, utilizing a radiation pressure sensor currently under development at INFN, Trieste. We show that such an experiment will be sensitive to a wide range of model parameters and signifies a pioneering effort searching for chameleons in unprobed paramterspace.

Baum, Sebastian

2014-01-01

127

Apparatus for processing electromagnetic radiation and method  

Science.gov (United States)

Measuring apparatus including a ruled member having alternate transparent and opaque zones. An optical coupler connecting the ruled member with electromagnetic radiation-conversion apparatus. The conversion apparatus may include a photomultiplier and a discriminator. Radiation impinging on the ruled member will, in part, be converted to electrical pulses which correspond to the intensity of the radiation. A method of processing electromagnetic radiation includes providing a member having alternating dark and light zones, establishing movement of the member through the beam of electromagnetic radiation with the dark zones interrupting passage of radiation through the rule, providing an optical coupler to connect a portion of the radiation with a conversion station where the radiation portion is converted into an electrical pulse which is related to the intensity of the radiation received at the conversion station. The electrical pulses may be counted and the digitized signals stored or permanently recorded to produce positional information.

Gatewood, George D. (Inventor)

1983-01-01

128

Various Edge Detection Methods for Foreground Detection?  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, we study different edge detection techniques, edge detection is one of the mostcommonly used operations in image analysis, and there are probably more algorithms in the literature forenhancing and detecting edges than any other single subject. The goal of edge detection process in a digitalimage is to determine the frontiers of all represented objects based on automatic processing of the colour orgray level information in each present pixel. An edge is the boundary between an object and the background,and indicates the boundary between overlapping objects. This means that if the edges in an image can beidentified accurately, all of the objects can be located and basic properties such as area, perimeter, and shapecan be measured. Since computer vision involves the identification and classification of objects in an image,edge detections is an essential tool.

Gurjeet kaur Seerha

2013-06-01

129

Calibration method for video and radiation imagers  

Science.gov (United States)

The relationship between the high energy radiation imager pixel (HERIP) coordinate and real-world x-coordinate is determined by a least square fit between the HERIP x-coordinate and the measured real-world x-coordinates of calibration markers that emit high energy radiation imager and reflect visible light. Upon calibration, a high energy radiation imager pixel position may be determined based on a real-world coordinate of a moving vehicle. Further, a scale parameter for said high energy radiation imager may be determined based on the real-world coordinate. The scale parameter depends on the y-coordinate of the moving vehicle as provided by a visible light camera. The high energy radiation imager may be employed to detect radiation from moving vehicles in multiple lanes, which correspondingly have different distances to the high energy radiation imager.

Cunningham, Mark F. (Oak Ridge, TN); Fabris, Lorenzo (Knoxville, TN); Gee, Timothy F. (Oak Ridge, TN); Goddard, Jr., James S. (Knoxville, TN); Karnowski, Thomas P. (Knoxville, TN); Ziock, Klaus-peter (Clinton, TN)

2011-07-05

130

Detecting solar chameleons through radiation pressure  

CERN Document Server

Light scalar fields can drive the accelerated expansion of the universe. Hence, they are obvious dark energy candidates. To make such models compatible with tests of General Relativity in the solar system and "fifth force" searches on Earth, one needs to screen them. One possibility is the so-called "chameleon" mechanism, which renders an effective mass depending on the local matter density. If chameleon particles exist, they can be produced in the sun and detected on earth exploiting the equivalent of a radiation pressure. Since their effective mass scales with the local matter density, chameleons can be reflected by a dense medium if their effective mass becomes greater than their total energy. Thus, under appropriate conditions, a flux of solar chameleons may be sensed by detecting the total instantaneous momentum transferred to a suitable opto-mechanical force/pressure sensor. We calculate the solar chameleon spectrum and the reach in the chameleon parameter space of an experiment using the preliminary re...

Baum, S; Hoffmann, D H H; Karuza, M; Semertzidis, Y K; Upadhye, A; Zioutas, K

2014-01-01

131

Reliability of pyuria detection method.  

Science.gov (United States)

The reliability of two methods for the detection of pyuria was studied in a total of 106 urine samples obtained from patients with identifiable underlying urinary tract disease. The coefficient of variation (CV) was significantly higher in the microscopic than in the counting chamber method. The CV obtained with the use of the KOVA slide 10 grid, a disposable and less expensive counting chamber, was identical to that obtained with the Bürker-Türk counting chamber. Only 50% of the patients who were proven to have pyuria of > or = 5 WBCs/HPF by the microscopic method had significant bacteriuria of > or = 10(4) bacteria per ml of urine. On the other hand, 95% and 90% of the patients who were proven to have pyuria of > or = 10 WBCs/mm3 with the Bürker-Türk and Fuchs-Rosenthal counting chambers had significant bacteriuria. It was concluded that the counting chamber provides a reliable method for the detection of pyuria and is highly predictive for the presence of significant bacteriuria. The KOVA slide 10 grid is an acceptable alternative to the regular counting chamber. PMID:7519582

Saito, A; Kawada, Y

1994-01-01

132

Detection and identification method employing Mossbauer isotopes  

International Nuclear Information System (INIS)

A detection/identification method for determining the presence of a Mossbauer isotope-containing taggant in a carrier material, e.g., explosives, weapons, currency, tax stamps, or identification documents. The detector includes a Mossbauer isotope-containing detecting substance that is identical to the taggant, and a sensing element responsive to the presence of the tagging substance in the carrier material, provided that the Mossbauer isotope of the tagging substance is in a state of resonance excitation and causes excitation of the Mossbauer isotope of the detecting substance. The sensing element is operatively associated with an indicator for indicating whether or not the sensing element has been actuated. The method is initiated by irradiating the carrier material while in detecting proximity to the detector, with radiation from a radioactive source comprising a Mossbauer isotope-containing substance which corresponds exactly to the taggant. In the case of explosives, identification of the manufacturer, date of manufacture or type of explosive, may be made even after detonation

133

Evaluation of methods to leak test sealed radiation sources  

International Nuclear Information System (INIS)

The methods for the leak testing of sealed radiation sources were reviewed. One hundred and thirty-one equipment vendors were surveyed to identify commercially available leak test instruments. The equipment is summarized in tabular form by radiation type and detector type for easy reference. The radiation characteristics of the licensed sources were reviewed and summarized in a format that can be used to select the most suitable detection method. A test kit is proposed for use by inspectors when verifying a licensee's test procedures. The general elements of leak test procedures are discussed

134

Organic materials and devices for detecting ionizing radiation  

Science.gov (United States)

A .pi.-conjugated organic material for detecting ionizing radiation, and particularly for detecting low energy fission neutrons. The .pi.-conjugated materials comprise a class of organic materials whose members are intrinsic semiconducting materials. Included in this class are .pi.-conjugated polymers, polyaromatic hydrocarbon molecules, and quinolates. Because of their high resistivities (.gtoreq.10.sup.9 ohmcm), these .pi.-conjugated organic materials exhibit very low leakage currents. A device for detecting and measuring ionizing radiation can be made by applying an electric field to a layer of the .pi.-conjugated polymer material to measure electron/hole pair formation. A layer of the .pi.-conjugated polymer material can be made by conventional polymer fabrication methods and can be cast into sheets capable of covering large areas. These sheets of polymer radiation detector material can be deposited between flexible electrodes and rolled up to form a radiation detector occupying a small volume but having a large surface area. The semiconducting polymer material can be easily fabricated in layers about 10 .mu.m to 100 .mu.m thick. These thin polymer layers and their associated electrodes can be stacked to form unique multi-layer detector arrangements that occupy small volume.

Doty, F. Patrick (Livermore, CA); Chinn, Douglas A. (Livermore, CA)

2007-03-06

135

Infrared radiation detection with a YBCO microbridge  

International Nuclear Information System (INIS)

Since the discovery of high-Tc superconductors, many researchers have studied the possibility of using them in optical devices, such as infrared radiation sensors (IRSs) and optically triggered switching devices with high-speed response. When a superconductive microbridge is irradiated with a certain light, two types of response can be observed: bolometric and nonbolometric. The bolometric response is proportional to dR/dT, the derivative of resistance with respect to temperature. Therefore, it reaches a maximum at the edge of the superconductive transition region. In this work a thin-film YBCO microbridge was fabricated for infrared radiation detection. The YBCO was deposited by rf-magnetron sputtering on a polished, MgO (100) single-crystal substrate. Ion-beam etching had to be done in increments to avoid heating the film to a temperature where its Tc was significantly lowered. The devices responded well, even to weak infrared radiation. Their typical noise-equivalent power and response values were 3.5 x 109/Hz and 19 V/W, respectively. At temperatures lower than the superconductive transition point, a nonbolometric photo response was confirmed, which was attributed to vortex motion. In this paper, the authors describe the bolometric behavior of the IRS device at the edge of the superconductive transition region and the nonbolometric behavior at lower temperatures and its temperature dependence. The two types of behavior are comparedce. The two types of behavior are compared and the origin of the nonbolometric response is discussed

136

Bubble Radiation Detection: Current and Future Capability  

Energy Technology Data Exchange (ETDEWEB)

Despite a number of noteworthy achievements in other fields, superheated droplet detectors (SDDs) and bubble chambers (BCs) have not been used for nuclear nonproliferation and arms control. This report examines these two radiation-detection technologies in detail and answers the question of how they can be or should be ''adapted'' for use in national security applications. These technologies involve closely related approaches to radiation detection in which an energetic charged particle deposits sufficient energy to initiate the process of bubble nucleation in a superheated fluid. These detectors offer complete gamma-ray insensitivity when used to detect neutrons. They also provide controllable neutron-energy thresholds and excellent position resolution. SDDs are extraordinarily simple and inexpensive. BCs offer the promise of very high efficiency ({approximately}75%). A notable drawback for both technologies is temperature sensitivity. As a result of this problem, the temperature must be controlled whenever high accuracy is required, or harsh environmental conditions are encountered. The primary findings of this work are listed and briefly summarized below: (1) SDDs are ready to function as electronics-free neutron detectors on demand for arms-control applications. The elimination of electronics at the weapon's location greatly eases the negotiability of radiation-detection technologies in general. (2) As a result of their high efficiency and sharp energy threshold, current BCs are almost ready for use in the development of a next-generation active assay system. Development of an instrument based on appropriately safe materials is warranted. (3) Both kinds of bubble detectors are ready for use whenever very high gamma-ray fields must be confronted. Spent fuel MPC and A is a good example where this need presents itself. (4) Both kinds of bubble detectors have the potential to function as low-cost replacements for conventional neutron detectors such as {sup 3}He tubes. For SDDs, this requires finding some way to get boron into the detector. For BCs, this requires finding operating conditions permitting a high duty cycle.

AJ Peurrung; RA Craig

1999-11-15

137

Explosives detection system and method  

Energy Technology Data Exchange (ETDEWEB)

A method of detecting explosives in a vehicle includes providing a first rack on one side of the vehicle, the rack including a neutron generator and a plurality of gamma ray detectors; providing a second rack on another side of the vehicle, the second rack including a neutron generator and a plurality of gamma ray detectors; providing a control system, remote from the first and second racks, coupled to the neutron generators and gamma ray detectors; using the control system, causing the neutron generators to generate neutrons; and performing gamma ray spectroscopy on spectra read by the gamma ray detectors to look for a signature indicative of presence of an explosive. Various apparatus and other methods are also provided.

Reber, Edward L. (Idaho Falls, ID); Jewell, James K. (Idaho Falls, ID); Rohde, Kenneth W. (Idaho Falls, ID); Seabury, Edward H. (Idaho Falls, ID); Blackwood, Larry G. (Idaho Falls, ID); Edwards, Andrew J. (Idaho Falls, ID); Derr, Kurt W. (Idaho Falls, ID)

2007-12-11

138

Exoplanet Detection: Radial Velocity Method  

Science.gov (United States)

The Exoplanet Detection: The Radial Velocity Method model simulates the detection of exoplanets by using the radial velocity method and the Doppler effect. In this simulation the exoplanet orbits the star (sun-sized) in circular motion via Kepler's third law.  The radial velocity of the star is determined from the velocity of the exoplanet.  This velocity is then used to calculate the Doppler shift of the Fraunhofer lines of the star.  In practice it is the Doppler shift of the Fraunhofer lines of the star that are detected and from this the radial velocity is inferred.  From this the mass and orbital period and average exoplanet-star separation are determined.  In the simulation the star-exoplanet system is shown as seen from Earth (edge on view) and from space (overhead view), and with the star and exoplanet sizes not shown to the scale of the orbit.  In addition, the Fraunhofer lines are shown.  The radial velocites of stars are such that the Doppler shifts are small, to compensate you may snap to the Na line and use the right-hand side slider to zoom in on that line to see wavelength shift.  The mass of the exoplanet (relative to the mass of Jupiter), the average star-exoplant separation (in AU), and the inclination of the system relative to Earth can be changed. The simulation uses Java 3D, if installed, to render the view the star and exoplanet. If Java 3D is not installed, the simulation will default to simple 3D using Java.

Belloni, Mario

2010-06-29

139

Aerial Radiation Detection Vehicle Manned and Unmanned Concepts  

International Nuclear Information System (INIS)

We are developing an Unmanned Aerial Radiation Detection Vehicle that will give new abilities to the Manned Aerial Radiation Detection Vehicle, Air-Ram. A comparison between the two systems will be given, and a report to our first Unmanned Aerial Radiation Detection Vehicle flight. Air-Ram The Air-Ram system, figure 1, has been developed to measure and display online radiation level measurements taken above the radiation area with a chopper. The detected radiation levels are presented on a topographical map with the flight path colored with the radiation intensities. The air crew and controllers on the ground are updated every two seconds. It enables first responders to complete and real time picture of a radiological event which is essential in order to be able to activate and direct ground operations if necessary. The system measures radiation levels and produces a spectrum graph used to identify the isotopes

140

Radiation and thermal characteristics of L5178Y-sensitive cells and usefulness of eosin staining method to detect heat-induced cell death  

International Nuclear Information System (INIS)

Radiosensitivity, thermosensitivity, drug sensitivity and their combined effects were investigated in mouse L5178Y-wild cells (LY-W) and L5178Y-sensitive cells (LY-S). The following results were obtained: LY-S were more radiosensitive than LY-W but were similar in their thermosensitivity. Thermotolerance induction was similar but the decay was faster in LY-W which had a shorter doubling time. The radiosensitizing effect of heating was similar in both cell lines. The thermal enhancement ratio was higher for a longer duration of heating at 42degC than for a shorter duration at 44degC, both of which exhibited a similar level of survival when applied alone. The eosin staining method was useful to detect heat-induced interphase death and thermal sensitizing effects of drugs. In LY-W, interphase death was the main mode of hyperthermic cell killing and was independent of the hyperthermic temperature, whereas in LY-S, the percentage of interphase death increased with the hyperthermic temperature. Procaine and bleomycin sensitized both cells to heat. Survival estimated by the eosin staining method shifted towards that obtained by colony forming method in heated LY-S after procaine. Sensitization to heat by procaine suggests that interphase death after hyperthermia is probably due to membrane damage. Comparison of the present work with previous ones, further suggests that with an increase in thermosensitivity, there is an increase in heat-induced interphase death. (author) 67 rat-induced interphase death. (author) 67 refs

141

Statistical methods in radiation physics  

CERN Document Server

This statistics textbook, with particular emphasis on radiation protection and dosimetry, deals with statistical solutions to problems inherent in health physics measurements and decision making. The authors begin with a description of our current understanding of the statistical nature of physical processes at the atomic level, including radioactive decay and interactions of radiation with matter. Examples are taken from problems encountered in health physics, and the material is presented such that health physicists and most other nuclear professionals will more readily understand the application of statistical principles in the familiar context of the examples. Problems are presented at the end of each chapter, with solutions to selected problems provided online. In addition, numerous worked examples are included throughout the text.

Turner, James E; Bogard, James S

2012-01-01

142

Method to detect biological particles  

International Nuclear Information System (INIS)

A medical-diagnostic method to detect immunological as well as other specific reactions is described. According to the invention, first reactive particles (e.g. antibodies) are adsorbed on the surface of a solid, non-reactive substrate. The coated substrate is subjected to a solution which one assumes to contain the second biological particles (e.g. antigens) which are specific to the first and form complexes with these. A preferential radioactive labelling (e.g. with iodine 125) of the second biological particle is then directly or indirectly carried out. Clearage follows labelling in order to separate the second biological particles from the first ones. A specific splitting agent can selectively break the bond of both types of particle. The splitting agent solution is finally separated off and its content is investigated for the presence of labelling. (VJ)

143

Immunofluorescence detection methods using microspheres  

Science.gov (United States)

Microsphere-based immunoassays were devised for compounds of agricultural and biomedical interest (e.g., digoxin, theophylline, and zearalenone). Commercially available microspheres with surface functional groups for chemical derivatization were used as solid carriers. After immobilizing the target substances, the surface of the haptenized microspheres was blocked by a protein to reduce aspecific binding. Competitive immunoassays were performed using the functionalized microspheres and antibodies labeled with horseradish peroxidase. Immunofluorescence signal amplification was achieved by enzyme-catalyzed reporter deposition (CARD). An epifluorescence microscope, a CCD camera interfaced with a computer, and microscopy image analysis software were employed for quantitative detection of fluorescent light emitted from individual microspheres. Integration of several such immunoassays and application of an optical encoding method enabled multianalyte determination. These immunoassays can also be utilized in an immunosensor array format. This immunoarray format could facilitate miniaturization and automation of multianalyte immunoassays.

Szurdoki, Ferenc; Michael, Karri L.; Agrawal, Divya; Taylor, Laura C.; Schultz, Sandra L.; Walt, David R.

1999-01-01

144

Methods for early defect detection and reduction of radiation exposure in periodic inspection and testing of safety-relevant pipework. Continuation of the tests with the potential drop method  

International Nuclear Information System (INIS)

Based on the good results obtained from the SR 2045 contract, the newly developed potential drop method was further examined for application in periodic inspections in nuclear facilities. Five installations in nuclear power plants - each tested for over about 1 year - confirm that the set up is suitable - if permantly installed - for continuous monitoring of indications found by NDT and locations particularly at risk. In addition, it can be used to replace ultrasonic and radiographic inspections. It has an advantage over these methods as the radiation exposure is lower and inspection results are more reliable. With a hand probe the method can be usefully applied to evaluate flaws for instance in austenitic steels what can be difficult for common NDT methods. Because of its advantages the method should be incorporated into the Nuclear Code. (orig.)

145

Radiation detection technique on the fishery foods  

International Nuclear Information System (INIS)

Recently irradiation of fishery products such as sea bream, lobster etc has been spreading in South-east Asia. It is thus necessary to establish a detection technique for irradiated foods . This study aimed to investigate the effects of irradiation on the production of tyrosine isomers with relation to the status of food sample (frozen and cold-storage) and also the stabilities of the isomers in frozen foods after irradiation. Production of tyrosin isomers (meta-tyrosine, ortho-tyrosine) due to ?-ray irradiation (5 kGy) were observed in the muscles of frozen prawns as well as those at room temperature and the contents of these isomers after the irradiation was not different between the two states of the sample. The content increased depending on the radiation dose. The contents of these tyrosine isomers were not changed after storage at -20degC for 120 days. Therefore, it was thought that the tyrosine isomers were available as an effective indicator for detection of an irradiated food. (M.N.)

146

Particle and photon detection for a neutron radiative decay experiment  

Energy Technology Data Exchange (ETDEWEB)

We present the particle and photon detection methods employed in a program to observe neutron radiative beta-decay. The experiment is located at the NG-6 beam line at the National Institute of Standards and Technology Center for Neutron Research. Electrons and protons are guided by a 4.6 T magnetic field and detected by a silicon surface barrier detector. Photons with energies between 15 and 750 keV are registered by a detector consisting of a bismuth germanate scintillator coupled to a large area avalanche photodiode. The photon detector operates at a temperature near 80 K in the bore of a superconducting magnet. We discuss CsI as an alternative scintillator, and avalanche photodiodes for direct detection of photons in the 0.1-10 keV range.

Gentile, T.R. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States)], E-mail: thomas.gentile@nist.gov; Dewey, M.S.; Mumm, H.P.; Nico, J.S.; Thompson, A.K. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Chupp, T.E. [University of Michigan, Ann Arbor, MI 48109 (United States); Cooper, R.L. [University of Michigan, Ann Arbor, MI 48109 (United States)], E-mail: cooperrl@umich.edu; Fisher, B.M.; Kremsky, I.; Wietfeldt, F.E. [Tulane University, New Orleans, LA 70118 (United States); Kiriluk, K.G.; Beise, E.J. [University of Maryland, College Park, MD 20742 (United States)

2007-08-21

147

Particle and photon detection for a neutron radiative decay experiment  

Science.gov (United States)

We present the particle and photon detection methods employed in a program to observe neutron radiative beta-decay. The experiment is located at the NG-6 beam line at the National Institute of Standards and Technology Center for Neutron Research. Electrons and protons are guided by a 4.6 T magnetic field and detected by a silicon surface barrier detector. Photons with energies between 15 and 750 keV are registered by a detector consisting of a bismuth germanate scintillator coupled to a large area avalanche photodiode. The photon detector operates at a temperature near 80 K in the bore of a superconducting magnet. We discuss CsI as an alternative scintillator, and avalanche photodiodes for direct detection of photons in the 0.1-10 keV range.

Gentile, T. R.; Dewey, M. S.; Mumm, H. P.; Nico, J. S.; Thompson, A. K.; Chupp, T. E.; Cooper, R. L.; Fisher, B. M.; Kremsky, I.; Wietfeldt, F. E.; Kiriluk, K. G.; Beise, E. J.

2007-08-01

148

Detection methods for irradiated mites and insects  

International Nuclear Information System (INIS)

Results of the study on the following tests for separation of irradiated pests from untreated ones are reported: (a) test for identification of irradiated mites (Acaridae) based on lack of fecundity of treated females; (b) test for identification of irradiated beetles based on their locomotor activity; (c) test for identification of irradiated pests based on electron spin resonance (ESR) signal derived from treated insects; (d) test for identification of irradiated pests based on changes in the midgut induced by gamma radiation; and (e) test for identification of irradiated pests based on the alterations in total proteins of treated adults. Of these detection methods, only the test based on the pathological changes induced by irradiation in the insect midgut may identify consistently either irradiated larvae or adults. This test is simple and convenient when a rapid processing technique for dehydrating and embedding the midgut is used. (author)

149

Reducing waste generation and radiation exposure by analytical method modification  

International Nuclear Information System (INIS)

The primary goal of an analytical support laboratory has traditionally been to provide accurate data in a timely and cost effective fashion. Added to this goal is now the need to provide the same high quality data while generating as little waste as possible. At the Savannah River Technology Center (SRTC), we have modified and reengineered several methods to decrease generated waste and hence reduce radiation exposure. These method changes involved improving detection limits (which decreased the amount of sample required for analysis), decreasing reaction and analysis time, decreasing the size of experimental set-ups, recycling spent solvent and reagents, and replacing some methods. These changes had the additional benefits of reducing employee radiation exposure and exposure to hazardous chemicals. In all cases, the precision, accuracy, and detection limits were equal to or better than the replaced method. Most of the changes required little or no expenditure of funds. This paper describes these changes and discusses some of their applications

150

Data-driven textile flaw detection methods  

OpenAIRE

This research develops three efficient textile flaw detection methods to facilitate automated textile inspection for the textile-related industries. Their novelty lies in detecting flaws with knowledge directly extracted from textile images, unlike existing methods which detect flaws with empirically specified texture features. The first two methods treat textile flaw detection as a texture classification problem, and consider that defect-free images of a textile fabric normally possess c...

Tian, Xuwen; ???

2012-01-01

151

Detection of electromagnetic radiation using micromechanical multiple quantum wells structures  

Science.gov (United States)

An apparatus and method for detecting electromagnetic radiation employs a deflectable micromechanical apparatus incorporating multiple quantum wells structures. When photons strike the quantum-well structure, physical stresses are created within the sensor, similar to a "bimetallic effect." The stresses cause the sensor to bend. The extent of deflection of the sensor can be measured through any of a variety of conventional means to provide a measurement of the photons striking the sensor. A large number of such sensors can be arranged in a two-dimensional array to provide imaging capability.

Datskos, Panagiotis G [Knoxville, TN; Rajic, Slobodan [Knoxville, TN; Datskou, Irene [Knoxville, TN

2007-07-17

152

85Kr detection by Cherenkov radiation measurement  

International Nuclear Information System (INIS)

Using a Packard liquid scintillation spectrometer, experiments were done to examine the possibility of determining 85Kr by Cherenkov counting in toluene. The test gas was a mixture (0.1 - 1 cm3) of 85Kr, N2 and air with a maximum activity concentration of 1010 Bq.m-3. The method proved to be suitable for the quantitative analysis of 85Kr, provided the effect of other radionuclides can be neglected. For a counting time of 6000 sec the lower limit of detection was determined as 0.8 Bq (2? level). (author)

153

Detection of radiation treatment of beans using DNA comet assay  

Science.gov (United States)

A simple technique of microgel electrophoresis of single cells (DNA Comet Assay) enabled a quick detection of radiation treatment of several kinds of leguminous beans (azuki, black, black eye, mung, pinto, red kidney and white beans). Each variety was exposed to radiation doses of 0.5, 1 and 5kGy covering the permissible limits for insect disinfestation. The cells or nuclei from beans were extracted in cold PBS, embedded in agarose on microscope slides, lysed between 15 and 60min in 2.5% SDS and electrophoresis was carried out at a voltage of 2V/cm for 2-2.5min. After silver staining, the slides were evaluated through an ordinary transmission microscope. In irradiated samples, fragmented DNA stretched towards the anode and the damaged cells appeared as a comet. The density of DNA in the tails increased with increasing radiation dose. However, in non-irradiated samples, the large molecules of DNA remained relatively intact and there was only minor or no migration of DNA; the cells were round or had very short tails only. Hence, the DNA comet assay provides an inexpensive, rapid and relatively simple screening method for the detection of irradiated beans.

Khan, Ashfaq A.; Khan, Hasan M.; Delincée, Henry

2002-03-01

154

Detection of radiation treatment of beans using DNA comet assay  

International Nuclear Information System (INIS)

A simple technique of microgel electrophoresis of single cells (DNA Comet Assay) enabled a quick detection of radiation treatment of several kinds of leguminous beans (azuki, black, black eye, mung, pinto, red kidney and white beans). Each variety was exposed to radiation doses of 0.5, 1 and 5 kGy covering the permissible limits for insect disinfestation. The cells or nuclei from beans were extracted in cold PBS, embedded in agarose on microscope slides, lysed between 15 and 60 min in 2.5% SDS and electrophoresis was carried out at a voltage of 2 V/cm for 2-2.5 min. After silver staining, the slides were evaluated through an ordinary transmission microscope. In irradiated samples, fragmented DNA stretched towards the anode and the damaged cells appeared as a comet. The density of DNA in the tails increased with increasing radiation dose. However, in non-irradiated samples, the large molecules of DNA remained relatively intact and there was only minor or no migration of DNA; the cells were round or had very short tails only. Hence, the DNA comet assay provides an inexpensive, rapid and relatively simple screening method for the detection of irradiated beans

155

Can we detect "Unruh radiation" in the high intensity lasers?  

OpenAIRE

An accelerated particle sees the Minkowski vacuum as thermally excited, which is called the Unruh effect. Due to an interaction with the thermal bath, the particle moves stochastically like the Brownian motion in a heat bath. It has been discussed that the accelerated charged particle may emit extra radiation (the Unruh radiation) besides the Larmor radiation, and experiments are under planning to detect such radiation by using ultrahigh intensity lasers. There are, however,...

Iso, Satoshi; Yamamoto, Yasuhiro; Zhang, Sen

2011-01-01

156

Single electron detection and spectroscopy via relativistic cyclotron radiation  

OpenAIRE

It has been understood since 1897 that accelerating charges must emit electromagnetic radiation. Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904. Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly. Here we demonstrate single-electron detection in a nove...

Asner, D. M.; Bradley, R. F.; Viveiros, L.; Doe, P. J.; Fernandes, J. L.; Fertl, M.; Finn, E. C.; Formaggio, J. A.; Furse, D.; Jones, A. M.; Kofron, J. N.; Laroque, B. H.; Leber, M.; Mcbride, E. L.; Miller, M. L.

2014-01-01

157

Methods of in vivo radiation measurement  

International Nuclear Information System (INIS)

Methods of and apparatus for in vivo radiation measurements relay on a MOSFET dosimeter of high radiation sensitivity with operates in both the passive mode to provide an integrated dose detector and active mode to provide an irradiation rate detector. A compensating circuit with a matched unirradiated MOSFET is provided to operate at a current designed to eliminate temperature dependence of the device. Preferably, the MOSFET is rigidly mounted in the end of a miniature catheter and the catheter is implanted in the patient proximate the radiation source. 13 figs

158

Monte Carlo Radiation Hydrodynamics with Implicit Methods  

OpenAIRE

We explore the application of Monte Carlo transport methods to solving coupled radiation-hydrodynamics problems. We use a time-dependent, frequency-dependent, 3-dimensional radiation transport code, that is special relativistic and includes some detailed microphysical interactions such as resonant line scattering. We couple the transport code to two different 1-dimensional (non-relativistic) hydrodynamics solvers: a spherical Lagrangian scheme and a Eulerian Godunov solver. ...

Roth, Nathaniel; Kasen, Daniel

2014-01-01

159

Terahertz and Mid Infrared Radiation Generation, Detection and Applications  

CERN Document Server

Terahertz (THz) and Mid-Infrared (MIR) radiation  (TERA-MIR) can be transmitted through nearly any material without causing biological harm. Novel and rapid methods of detection can be created with devices operation in these spectral ranges allowing scanning for weapons, detecting hidden explosives (including plastic landmines), controlling the quality of food and a host of other exciting applications.  This book focuses on mathematical and physical aspects of the field, on unifying these two spectral domains (THz and MIR) with regard to common sources, detectors, materials and applications, and on key interdisciplinary topics. The main THz and MIR source is the quantum cascade laser (QCL). Thus significant attention is paid to the challenge of turning this advanced technology into affordable commercial devices so as to exploit its enormous potential. However other alternatives to THz QCLs are also presented, e.g.  sub-terahertz imaging from avalanching GaAs bipolar transistors, Josephson junctions as THz ...

Pereira, Mauro F

2011-01-01

160

Detection of radiation-induced changes in electrochemical properties of austenitic stainless steels using miniaturized specimens and the single-loop electrochemical potentiokinetic reactivation method  

Energy Technology Data Exchange (ETDEWEB)

Single-loop electrochemical potentiokinetic reactivation testing of miniaturized (TEM) specimens can provide reliable data comparable to data obtained with larger specimens. Significant changes in electrochemical properties (increased reactivation current and Flade potential) were detected for PCA and type 316 stainless steels irradiated at 200--420{degrees}C up to 7--9 dpa. Irradiations in the FFTF Materials Open Test Assembly and in the Oak Ridge Research Reactor are reported on. 45 figs., 5 tabs., 52 refs.

Inazumi, T.; Bell, G.E.C.; Kenik, E.A.; Kiuchi, K.

1993-01-01

161

Detection of radiation-induced changes in electrochemical properties of austenitic stainless steels using miniaturized specimens and the single-loop electrochemical potentiokinetic reactivation method  

International Nuclear Information System (INIS)

Single-loop electrochemical potentiokinetic reactivation testing of miniaturized (TEM) specimens can provide reliable data comparable to data obtained with larger specimens. Significant changes in electrochemical properties (increased reactivation current and Flade potential) were detected for PCA and type 316 stainless steels irradiated at 200--420 degrees C up to 7--9 dpa. Irradiations in the FFTF Materials Open Test Assembly and in the Oak Ridge Research Reactor are reported on. 45 figs., 5 tabs., 52 refs

162

Detection of radiation-induced changes in electrochemical properties of austenitic stainless steels using miniaturized specimens and the single-loop electrochemical potentiokinetic reactivation method  

Energy Technology Data Exchange (ETDEWEB)

Single-loop electrochemical potentiokinetic reactivation testing of miniaturized (TEM) specimens can provide reliable data comparable to data obtained with larger specimens. Significant changes in electrochemical properties (increased reactivation current and Flade potential) were detected for PCA and type 316 stainless steels irradiated at 200--420[degrees]C up to 7--9 dpa. Irradiations in the FFTF Materials Open Test Assembly and in the Oak Ridge Research Reactor are reported on. 45 figs., 5 tabs., 52 refs.

Inazumi, T.; Bell, G.E.C.; Kenik, E.A.; Kiuchi, K.

1993-01-01

163

Line Detection Methods for Spectrogram Images  

OpenAIRE

Accurate feature detection is key to higher level decisions regarding image content. Within the domain of spectrogram track detection and classification, the detection problem is compounded by low signal to noise ratios and high track appearance variation. Evaluation of standard feature detection methods present in the literature is essential to determine their strengths and weaknesses in this domain. With this knowledge, improved detection strategies can be developed. This paper presents a c...

Lampert, Thomas; O Keefe, Simon; Pears, Nick

2009-01-01

164

Measuring methods for whole beta radiations  

International Nuclear Information System (INIS)

It is necessary to know rapidly the outline information on environmental radiation depending on the conditions of releasing radioactive material into environment or the purposes of measuring them. Whole beta radiation measurement is used for this purpose. In other words, though nuclides are not identified, approximate radioactive decay is determined. The factors affecting the results of the whole beta radiation measurement include the proportion of beta emission of samples, continuity of energy spectra of beta ray, selection of calibration sources, selection and characteristics of measuring instruments, and self absorption by the samples. The maximum disturbance for detecting artificial radiations is the contribution of natural radioactivity contained in samples, though a part of the above factors is improved by correction. Since estimation of the disturbance so far involved comparatively large error, the whole beta radiation is expressed in a form of including the contribution of natural radioactivity. Though there are many factors for making the results uncertain, the whole beta radiation measurement offers still useful result. However, it is not suitable in case of soft ? nuclides such as tritium and 14C are dominant. The contents are divided into nine chapters including introduction, measurement criteria, rain and dust, sea water, land water, crops, milk, soil and sea bottom sediments, and marine organisms. This manual is the revised third edition, and manual is the revised third edition, and the revised parts are summarized in appendix 1. (Wakatsuki, Y.)

165

Information-Based Examination of Variable Hierarchy in Radiation Detection  

Science.gov (United States)

Of considerable importance in the development of a general program of information-based materials design is the manner in which materials data are stored, retrieved and analyzed. In the area of radiation detection materials, the variable spaces tend to be large and property measurements (and computations) of candidate materials are not abundant. Moreover, measurements and calculations of the same nominal quantity (e.g. bandgap) are typically based on differing and incompletely defined environments, and may not be directly comparable. The identification of parameter degeneracies, reduced spaces and transferability within the information hierarchy have become critical issues for the development of effective structure mappings for making inferences on these systems. As the initial framework for a materials-informatics approach to radiation detection materials, we have explored the use of both supervised (Support Vector Machines( SVM); Linear Discriminant(LDA)) and unsupervised (Principal Component (PCA)) learning methods for the development of structural signature models. Application of these methods yields complementary results, both of which are necessary to reduce parameter space and variable degeneracy. Using a crystal structure classification test, nonlinear SVM significantly increases predictive performance, suggesting trade-offs between smaller descriptor spaces and simpler linear models.

Ferris, Kim; Webb-Robertson, Bobbie-Jo; Jones, Dumont

2006-03-01

166

FACE DETECTION USING EIGEN METHOD  

Directory of Open Access Journals (Sweden)

Full Text Available As continual research is being conducted in the area of computer vision, one of the most practical applications under vigorous development is in the construction of a robust face detection system. While the problem of detecting faces under various variations remains largely unsolved, a demonstration system as proof of concept that such systems are now becoming practical have been developed. A system capable of reliable detection, with reduced constraints in regards to the position and orientation of the face and the illumination and background of the image, has been implemented. Those face detection system is based upon “eigenfaces”, which has been separated into three major modules – pre-processing, construction of face space and face localization. A completely robust real-time face detectionsystem is still under heavy investigation and development, the implemented systems are still serving as an extendable foundation for future research.

HASHAAM NAEEM

2012-03-01

167

Crystallization method employing microwave radiation  

International Nuclear Information System (INIS)

This invention relates to a method of crystallizing materials from aqueous crystallization media. Zeolite materials, both natural and synthetic, have been demonstrated in the past to have catalytic properties for various types of hydrocarbon conversion. Certain zeolitic materials are ordered, porous crystalline metallosilicates having a definite crystalline structure as determined by X-ray diffraction within which there are a number of smaller cavities which may be interconnected by a number of still smaller channels or pores. These cavities and pores are uniform in size within a specific zeolite material. Since the dimensions of these pores are such as to accept for adsorption molecules of certain dimensions while rejecting those of large dimensions, these materials have come to be known as molecular sieves and are utilized in a variety of ways to take advantage of these properties. (author). 3 tabs

168

Frontal Face Detection Methods ???Neural Networks and Aggressive Learning Algorithm  

OpenAIRE

In this research work, a face detection method is presented. Face detection is the first step of face Recognition methods. Face detection is a difficult task in Pattern. There are different methods of face detection namely-Knowledge Based Face Detection Methods, Feature Based Face Detection Methods, Template Based Face Detection Methods and Appearnce Based Face Detection Methods. But here we divided basically in two methods for face detection (i) image based methods (ii) feature based methods...

sushma jaiswal

2011-01-01

169

FY2008 Report on GADRAS Radiation Transport Methods.  

Energy Technology Data Exchange (ETDEWEB)

The primary function of the Gamma Detector Response and Analysis Software (GADRAS) is the solution of inverse radiation transport problems, by which the con-figuration of an unknown radiation source is inferred from one or more measured radia-tion signatures. GADRAS was originally developed for the analysis of gamma spec-trometry measurements. During fiscal years 2007 and 2008, GADRAS was augmented to implement the simultaneous analysis of neutron multiplicity measurements. This report describes the radiation transport methods developed to implement this new capability. This work was performed at the direction of the National Nuclear Security Administration's Office of Nonproliferation Research and Development. It was executed as an element of the Proliferation Detection Program's Simulation, Algorithm, and Modeling element. Acronyms BNL Brookhaven National Laboratory CSD Continuous Slowing-Down DU depleted uranium ENSDF Evaluated Nuclear Structure Data Files GADRAS Gamma Detector Response and Analysis Software HEU highly enriched uranium LANL Los Alamos National Laboratory LLNL Lawrence Livermore National Laboratory NA-22 Office of Nonproliferation Research and Development NNDC National Nuclear Data Center NNSA National Nuclear Security Administration ODE ordinary differential equation ONEDANT One-dimensional diffusion accelerated neutral particle transport ORNL Oak Ridge National Laboratory PARTISN Parallel time-dependent SN PDP Proliferation Detection Program RADSAT Radiation Scenario Analysis Toolkit RSICC Radiation Safety Information Computational Center SAM Simulation, Algorithms, and Modeling SNL Sandia National Laboratories SNM special nuclear material ToRI Table of Radioactive Isotopes URI uniform resource identifier XML Extensible Markup Language

Mattingly, John K.; Mitchell, Dean James; Harding, Lee; Varley, Eric S.; Hilton, Nathan R. [Sandia National Laboratories, Livermore, CA

2008-10-01

170

Leak detection by vibrational diagnostic methods  

International Nuclear Information System (INIS)

The possibilities and methods of leak detection due to mechanical failures in nuclear power plants are reviewed on the basis of the literature. Great importance is attributed to vibrational diagnostic methods for their adventageous characteristics which enable them to become final leak detecting methods. The problems of noise analysis, e.g. leak detection by impact sound measurements, probe characteristics, gain problems, probe selection, off-line analysis and correlation functions, types of leak noises etc. are summarized. Leak detection based on noise analysis can be installed additionally to power plants. Its maintenance and testing is simple. On the other hand, it requires special training and measuring methods. (Sz.J.)

171

Main Achievements 2003-2004 - Interdisciplinary Research - Radiation detection methods for health, earth and environmental sciences - Natural radioactive elements in the environment  

International Nuclear Information System (INIS)

Research on natural radioactive elements in the environment has been conducted. The main activities are focused on measurements of isotopes arising from natural radioactive series (especially radon). In 2004, the first two parts of survey within the frame of scientific cooperation between ''Vinca'' Institute and IFJ PAN were completed. Field measurements were carried out in Niska Banja Spa (Serbia and Montenegro). In this region extremely high radon (222Rn) concentrations in soil gas, to above 2 000 kBq/m3., very high values of radon exhalation rates (1,5 Bq/m2s) and radon concentration in water samples (> 500 Bq/l) were observed. Indoor radon concentrations in some houses exceeded 10 kBq/m3. A special model and computer code were developed for calculating and visualising radon distribution and its migration into houses (PhD thesis). At the Radon Study Field located in IFJ PAN, the influence of different parameters on the radon exhalation process are studied and changes of radon concentration in soil are investigated. The natural radiation level plays an important role in low background gamma spectroscopy. Long-term measurements of the gamma background level are being performed and their changes (e.g., post-Chernobyl or solar activity induced) studied

172

OH detection by absorption of frequency-doubled diode laser radiation at 308 nm  

OpenAIRE

Radiation at 308 nm has been obtained by frequency doubling the output of a commercial diode laser cooled to 165 K. A single pass through a crystal of LiIO 3 converted 1 mW of 616 nm radiation to 50 pW of UV, and this was used to detect the OH radical in absorption in a flow tube. Possible extensions of the method for detection of OH in the atmosphere are discussed.

Barry, Hr; Bakowski, B.; Corner, L.; Freegarde, T.; Hawkins, Otw; Hancock, G.; Jacobs, Rmj; Peverall, R.; Ritchie, Gad

2000-01-01

173

Physical problems in measuring the blood flow through organs by means of inhalation of noble gases with special regard to three-dimensional methods of radiation detection  

International Nuclear Information System (INIS)

The paper gives a survey of the current indirect methods of blood flow measurement with the aid of radioactive isotopes. Liver, spleen, and kidneys were investigated in order to find out whether noble gas washout may also be carried out by inhalation and external measurement alone, which do not involve any disconfort to the patient. Compartment models were established for different organs, and the conditions of measurement chosen were such that the parameters of blood flow could be determined unambiguously. The problems encountered in liver blood flow determination are mainly due to the human anatomy. The complicated blood flow pattern makes the use of freely diffusible tracers advisable, especially in pathological cases. The values measured in normal livers using the inhalation method are consistent with the values obtained by other direct and indirect methods. In pathological cases, further information is required concerning the fat content of the liver. This information can be provided by means of a biopsy or indirectly by a double Xe/Kr measurement. Up to a fat content of 10% of the moist weight, the error in the blood flow values measured is < 20%. 3-dimensional measurements with ?-?-coincidences will help to eliminate possible sources of errors such as superimposed tissues and to shorten the time of measurement. The first in-vivo measurements carried out in the liver are presented. The inhalation method will not lead to better regional differentiation, since tbetter regional differentiation, since the tissue can only be enriched with low activity concentrations. For establishing general quantitative mean values, however, it is the ideal method owing to its reasonableness, absence of trauma, to the fact that it can be repeated after a short interval, and to its independence of the intact function of the organ. (orig./HP)

174

Numerical Methods for Radiation Magnetohydrodynamics in Astrophysics  

Energy Technology Data Exchange (ETDEWEB)

We describe numerical methods for solving the equations of radiation magnetohydrodynamics (MHD) for astrophysical fluid flow. Such methods are essential for the investigation of the time-dependent and multidimensional dynamics of a variety of astrophysical systems, although our particular interest is motivated by problems in star formation. Over the past few years, the authors have been members of two parallel code development efforts, and this review reflects that organization. In particular, we discuss numerical methods for MHD as implemented in the Athena code, and numerical methods for radiation hydrodynamics as implemented in the Orion code. We discuss the challenges introduced by the use of adaptive mesh refinement in both codes, as well as the most promising directions for future developments.

Klein, R I; Stone, J M

2007-11-20

175

Robust statistical methods for automated outlier detection  

Science.gov (United States)

The computational challenge of automating outlier, or blunder point, detection in radio metric data requires the use of nonstandard statistical methods because the outliers have a deleterious effect on standard least squares methods. The particular nonstandard methods most applicable to the task are the robust statistical techniques that have undergone intense development since the 1960s. These new methods are by design more resistant to the effects of outliers than standard methods. Because the topic may be unfamiliar, a brief introduction to the philosophy and methods of robust statistics is presented. Then the application of these methods to the automated outlier detection problem is detailed for some specific examples encountered in practice.

Jee, J. R.

1987-01-01

176

Small Teleoperated Robot for Nuclear Radiation and Chemical Leak Detection  

OpenAIRE

In order to meet the actual requirements of nuclear radiation and chemical leak detection, and emergency response, a new small teleoperated robot for nuclear radiation and chemical detection is proposed. A small?size robot is manufactured according to technical requirements and the overall structure and control system is described. Meanwhile, based on the principles of human?robot interaction, a user?friendly human?robot interaction interface is designed to provide a good telepresence...

Kui Qian; Aiguo Song; Jiatong Bao; Huatao Zhang

2012-01-01

177

Radiation interaction in matter and principles of detection  

Science.gov (United States)

The mechanisms of interaction of radiation in matter are reviewed. The energy losses and ranges of particles in matter, the attenuation of radiation in matter are discussed. These mechanisms are at the base of the particle detection principles and the operation of particle detectors. Relevance of these mechanisms for particle therapy of cancer and medical imaging is outlined.

Leroy, Claude

2010-01-01

178

Statistical Studies on Sequential Probability Ratio Test for Radiation Detection  

International Nuclear Information System (INIS)

A Sequential Probability Ratio Test (SPRT) algorithm helps to increase the reliability and speed of radiation detection. This algorithm is further improved to reduce spatial gap and false alarm. SPRT, using Last-in-First-Elected-Last-Out (LIFELO) technique, reduces the error between the radiation measured and resultant alarm. Statistical analysis determines the reduction of spatial error and false alarm

179

Pavement Crack Detection Using Spectral Clustering Method  

Directory of Open Access Journals (Sweden)

Full Text Available Pavement crack detection plays an important role in pavement maintaining and management, nowadays, which could be performed through remote image analysis. Thus, edges of pavement crack should be extracted in advance; in general, traditional edge detection methods don’t consider phase information and the spatial relationship between the adjacent image areas to extract the edges. To overcome the deficiency of the traditional approaches, this paper proposes a pavement crack detection algorithm based on spectral clustering method. Firstly, a measure of similarity between pairs of pixels is taken into account through orientation energy. Then, spatial relationship is needed to find regions where similarity between pixels in a given region is high and similarity between pixels in different regions is low. After that, crack edge detection is completed with spectral clustering method. The presented method has been run on some real life images of pavement crack, experimental results display that the crack detection method of this paper could obtain ideal result.

Jin Huazhong

2015-01-01

180

Application of Terahertz Radiation to the Detection of Corrosion under the Shuttle's Thermal Protection System  

Science.gov (United States)

There is currently no method for detecting corrosion under Shuttle tiles except for the expensive process of tile removal and replacement; hence NASA is investigating new NDE methods for detecting hidden corrosion. Time domain terahertz radiation has been applied to corrosion detection under tiles in samples ranging from small lab samples to a Shuttle with positive results. Terahertz imaging methods have been able to detect corrosion at thicknesses of 5 mils or greater under 1" thick Shuttle tiles and 7-12 mils or greater under 2" thick Shuttle tiles.

Madaras, Eric I.; Anastasi, Robert F.; Smith, Stephen W.; Seebo, Jeffrey P.; Walker, James L.; Lomness, Janice K.; Hintze, Paul E.; Kammerer, Catherine C.; Winfree, William P.; Russell, Richard W.

2007-01-01

181

Detection of irradiated pulses by PSL method  

International Nuclear Information System (INIS)

Photostimulated luminescence (PSL) as a screening method is very simple and rapid to detect irradiated foods but various disadvantages (light induced fading of PSL signal or response to clean foods with minerals insensitive to PSL measurement). In this study the characteristics of radiation induced PSL for 10 kinds of pulses (Chinese Soybean and Adzuki bean, Pinto bean, Cowpea, Green gram, Canadian Blue pea and Soybean, American Black-eyed pea and Chickpea, Red Kidney Bean) were investigated. The screening-PSL (s-PSL) cumulate counts of pulses significantly increased with irradiation dose up to 3 kGy. The s-PSL cumulate counts of irradiated pulses gradually decreased with increasing storage periods. The s-PSL cumulate counts of all pulse samples irradiated at a minimum dose of 0.5kGy exceeded considerably the upper screening threshold (5000 counts) regardless of storage period. Calibrated PSL (Cal-PSL) were obtained by re-irradiating the pulse samples with a gamma ray dose of 1 kGy and the PSL ratios (s-PSL/Cal-PSL) were calculated for normalization of sensitivity of the pulse samples. The PSL ratio at each irradiation dose was almost similar regardless of kind of pulses. (author)

182

Can we detect "Unruh radiation" in the high intensity lasers?  

CERN Document Server

An accelerated particle sees the Minkowski vacuum as thermally excited, which is called the Unruh effect. Due to an interaction with the thermal bath, the particle moves stochastically like the Brownian motion in a heat bath. It has been discussed that the accelerated charged particle may emit extra radiation (the Unruh radiation) besides the Larmor radiation, and experiments are under planning to detect such radiation by using ultrahigh intensity lasers. There are, however, counterarguments that the radiation is canceled by an interference effect between the vacuum fluctuation and the radiation from the fluctuating motion. In this reports, we review our recent analysis on the issue of the Unruh radiation. In this report, we particularly consider the thermalization of an accelerated particle in the scalar QED, and derive the relaxation time of the thermalization.

Iso, Satoshi; Zhang, Sen

2011-01-01

183

Rapid methods for detection of bacteria  

OpenAIRE

Traditional methods for detection of bacteria in drinking water e.g. Heterotrophic Plate Counts (HPC) or Most Probable Number (MNP) take 48-72 hours to give the result. New rapid methods for detection of bacteria are needed to protect the consumers against contaminations. Two rapid methods: Measurements of Adosine Triphosphate and BactiQuantTM have shown promising results as new monitoring tools, which gives the result within minutes/hours.

Corfitzen, Charlotte B.; Andersen, B. Ø.; Miller, M.; Ursin, C.; Arvin, Erik; Albrechtsen, Hans-jørgen

2006-01-01

184

Radiation methods of impregnating wooden cultural objects  

International Nuclear Information System (INIS)

The process was studied of polymerization in wood at low dose rates of gamma radiation. It was demonstrated that at radiation doses below the optimal level of 1.0 kGy.h-1, polymerization in wood decreased significantly. It was found that the molecular weight of polymethyl methacrylate prepared by radiation polymerization in samples of linden tree wood increased with decreasing dose rate and decreased with growing dose. It was also shown that the final size of samples after polymerization was the bigger the higher was the content of polymers in the wood attained. A study of radiation copolymerization of methyl methacrylate with butyl methacrylate in wood showed that the addition of butyl methacrylate in the monomer mixture increased the polymer yield in the wood and reduced moisture expansion of the wood during polymerization. In order to test the possible applications of obtained results a number of experiments were made which showed that the use of radiation polymerization is promising in wood which is not polychromatic. The wood surface following impregnation remained unchanged and restoration could be continued. In case of polychrom wood sculptures the application of the method was promising for tempera and gilding using a dose of less than 40 kGy at a dose rate of 1 kGy/h. In case of polychromatic wood sculptures with addition of oil binders there was the danger of damaging the object. (J.B.). 4 figs., 2 tabs., 2 refs2 refs

185

Nonlinear response matrix methods for radiative transfer  

International Nuclear Information System (INIS)

A nonlinear response matrix formalism is presented for the solution of time-dependent radiative transfer problems. The essential feature of the method is that within each computational cell the temperature is calculated in response to the incoming photons from all frequency groups. Thus the updating of the temperature distribution is placed within the iterative solution of the spaceangle transport problem, instead of being placed outside of it. The method is formulated for both grey and multifrequency problems and applied in slab geometry. The method is compared to the more conventional source iteration technique. 7 refs., 1 fig., 4 tabs

186

Spectral analysis method for detecting an element  

Energy Technology Data Exchange (ETDEWEB)

A method for detecting an element is described and which includes the steps of providing a gamma-ray spectrum which has a region of interest which corresponds with a small amount of an element to be detected; providing nonparametric assumptions about a shape of the gamma-ray spectrum in the region of interest, and which would indicate the presence of the element to be detected; and applying a statistical test to the shape of the gamma-ray spectrum based upon the nonparametric assumptions to detect the small amount of the element to be detected.

Blackwood, Larry G [Idaho Falls, ID; Edwards, Andrew J [Idaho Falls, ID; Jewell, James K [Idaho Falls, ID; Reber, Edward L [Idaho Falls, ID; Seabury, Edward H [Idaho Falls, ID

2008-02-12

187

Synchrotron radiation detection under conditions of pulse noises  

International Nuclear Information System (INIS)

A two-channel system for detecting synchrotron radiation is described. It is employed in a prototype collective heavy ion accelerator under conditions of a high-level electromagnetic noise. The detection is conducted in the 0.4 to 4.5 ?m spectral region in two channels, a silicon photodiode serving as a detector in one of the channels, a lead selenide photoresistor - in the other. The system realizes efficient suppression of electromagnetic crosstalks. A relative accuracy of the synchrotron radiation amplitude measurement makes up 0.2%. The advantage of the system described is a possibility of positioning the synchrotron radiation detectors in the direct vicinity of the radiation source, which excludes the necessity of optical contact. The system is employed as a beam monitor for detecting heavy ions in the prototype collective field accelerator

188

Spectral methods to detect surface mines  

Science.gov (United States)

Over the past five years, advances have been made in the spectral detection of surface mines under minefield detection programs at the U. S. Army RDECOM CERDEC Night Vision and Electronic Sensors Directorate (NVESD). The problem of detecting surface land mines ranges from the relatively simple, the detection of large anti-vehicle mines on bare soil, to the very difficult, the detection of anti-personnel mines in thick vegetation. While spatial and spectral approaches can be applied to the detection of surface mines, spatial-only detection requires many pixels-on-target such that the mine is actually imaged and shape-based features can be exploited. This method is unreliable in vegetated areas because only part of the mine may be exposed, while spectral detection is possible without the mine being resolved. At NVESD, hyperspectral and multi-spectral sensors throughout the reflection and thermal spectral regimes have been applied to the mine detection problem. Data has been collected on mines in forest and desert regions and algorithms have been developed both to detect the mines as anomalies and to detect the mines based on their spectral signature. In addition to the detection of individual mines, algorithms have been developed to exploit the similarities of mines in a minefield to improve their detection probability. In this paper, the types of spectral data collected over the past five years will be summarized along with the advances in algorithm development.

Winter, Edwin M.; Schatten Silvious, Miranda

2008-04-01

189

GMDD: a database of GMO detection methods  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Since more than one hundred events of genetically modified organisms (GMOs have been developed and approved for commercialization in global area, the GMO analysis methods are essential for the enforcement of GMO labelling regulations. Protein and nucleic acid-based detection techniques have been developed and utilized for GMOs identification and quantification. However, the information for harmonization and standardization of GMO analysis methods at global level is needed. Results GMO Detection method Database (GMDD has collected almost all the previous developed and reported GMOs detection methods, which have been grouped by different strategies (screen-, gene-, construct-, and event-specific, and also provide a user-friendly search service of the detection methods by GMO event name, exogenous gene, or protein information, etc. In this database, users can obtain the sequences of exogenous integration, which will facilitate PCR primers and probes design. Also the information on endogenous genes, certified reference materials, reference molecules, and the validation status of developed methods is included in this database. Furthermore, registered users can also submit new detection methods and sequences to this database, and the newly submitted information will be released soon after being checked. Conclusion GMDD contains comprehensive information of GMO detection methods. The database will make the GMOs analysis much easier.

Guo Rong

2008-06-01

190

Methods and systems for remote detection of gases  

Science.gov (United States)

Novel systems and methods for remotely detecting at least one constituent of a gas via infrared detection are provided. A system includes at least one extended source of broadband infrared radiation and a spectrally sensitive receiver positioned remotely from the source. The source and the receiver are oriented such that a surface of the source is in the field of view of the receiver. The source includes a heating component thermally coupled to the surface, and the heating component is configured to heat the surface to a temperature above ambient temperature. The receiver is operable to collect spectral infrared absorption data representative of a gas present between the source and the receiver. The invention advantageously overcomes significant difficulties associated with active infrared detection techniques known in the art, and provides an infrared detection technique with a much greater sensitivity than passive infrared detection techniques known in the art.

Johnson, Timothy J

2012-09-18

191

Determination of defect dimensions and location in welded joints during radiation flaw detection  

International Nuclear Information System (INIS)

Calculation methods and methods of determining defect dimensions and location outside the axis of welded oint, during radiation flow detection, are considered. Hystogram of defect distribution by width of the welded joint, is presented. A case of defect occurrence outside the joint axis during welding multilayer tubes of light and non-ferrous metals, is investigated

192

Radionuclide detection and analysis: A comparison of radiation counting and mass spectrometric (ICP/MS) capabilities  

International Nuclear Information System (INIS)

The detection and determination of radionuclide constituents in environmental and process samples has traditionally been performed through observation of the radionuclide's inherent radiation(s) associated with the decay of these unstable nuclei. For short and medium half-life radionuclides, this approach generally yields excellent quantitative results. However, determination of the more stable nuclei, i.e., radionuclides with longer half-lives, and/or radionuclides which decay through low energy radiation(s) (e.g., I-129 and Tc-99), is often impractical using classical decay counting methods. The authors have investigated the application of inductively coupled plasma mass spectrometry (ICP/MS) to the detection and quantitation of radionuclides. The potential for ICP/MS relative to radiation counting can be clarified by evaluating each technique on the basis of its inherent ability to observe signal counts. In order to do this, a brief and admittedly over-simplified discussion of the parameters related to detection of radionuclides by conventional radiation detection methods must be compared with the detection sensitivity offered by ICP/MS techniques

193

Single electron detection and spectroscopy via relativistic cyclotron radiation  

CERN Document Server

It has been understood since 1897 that accelerating charges must emit electromagnetic radiation. Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904. Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly. Here we demonstrate single-electron detection in a novel radiofrequency spec- trometer. We observe the cyclotron radiation emitted by individual magnetically-trapped electrons that are produced with mildly-relativistic energies by a gaseous radioactive source. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta elec- tron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay endpoint, and this work demonstrates a fundamentally new approach to precision beta sp...

Asner, D M; de Viveiros, L; Doe, P J; Fernandes, J L; Fertl, M; Finn, E C; Formaggio, J A; Furse, D; Jones, A M; Kofron, J N; LaRoque, B H; Leber, M; McBride, E L; Miller, M L; Mohanmurthy, P; Monreal, B; Oblath, N S; Robertson, R G H; Rosenberg, L J; Rybka, G; Rysewyk, D; Sternberg, M G; Tedeschi, J R; Thummler, T; VanDevender, B A; Woods, N L

2014-01-01

194

GC ‘Multi-Analyte’ Detection Method  

International Nuclear Information System (INIS)

Elaborated methodologies for GC multi-analyte detection are presented, comprising the steps of method development, chromatographic conditions and procedures including the determination of relative retention times and summary results tables. (author)

195

An Efficient Method of Small Targets Detection in Low SNR  

International Nuclear Information System (INIS)

In this paper, an efficient method based on nonlinear adaptive filtering is proposed to detect the small IR target of low SNR under the complex background. The morphologic filter can be constructed firstly based on the IR radiation traits of low SNR small targets in the complex background and then a morphological method is used to eliminate the influence of the unbalance background to the image segmentation. Next an algorithm of adaptive threshold segmentation is adopted in order to select the small moving target and the noise points. Finally, on the basis of image sequences, the satisfactory targets detection is accomplished after eliminating wrong point targets. The method presented in this paper can effectively suppress the noise and the air background of the original image, enhance the ability of point target detection in single frame

196

TROL - Solving the underwater radiation detection enigma  

International Nuclear Information System (INIS)

Designed by Fathoms in consultation with UKAEA, Dounreay, to detect buried radiological particles in ground 50m below the sea surface, TROL (Tracked Remote Offshore Logging) is the world's first tracked robotic system capable of delivering gamma spectroscopy in real-time, the genesis of which developed from Fathoms diving and undersea systems technology. This short article examines how an integrated approach to science and technology can be managed through quality processes to deliver superior solutions. The tracked ROV (Remote Operated Vehicle) is designed specifically to meet the challenging demands of real-time subsea particle detection. Positioning of the vehicle by the ultra-short baseline acoustic system was integrated with the surface support vessel's differential GPS navigation system to produce accurate positions of detected particles. (author)

197

TROL - Solving the underwater radiation detection enigma  

Energy Technology Data Exchange (ETDEWEB)

Designed by Fathoms in consultation with UKAEA, Dounreay, to detect buried radiological particles in ground 50m below the sea surface, TROL (Tracked Remote Offshore Logging) is the world's first tracked robotic system capable of delivering gamma spectroscopy in real-time, the genesis of which developed from Fathoms diving and undersea systems technology. This short article examines how an integrated approach to science and technology can be managed through quality processes to deliver superior solutions. The tracked ROV (Remote Operated Vehicle) is designed specifically to meet the challenging demands of real-time subsea particle detection. Positioning of the vehicle by the ultra-short baseline acoustic system was integrated with the surface support vessel's differential GPS navigation system to produce accurate positions of detected particles. (author)

Cassidy, J

2005-03-15

198

Radiation shielding facility and radiation shielding method at the facility  

International Nuclear Information System (INIS)

A space for installing a shielding door is disposed to a radiation shielding wall opposed to a radiation shielding wall having an opening across a labyrinth, and the shielding door is disposed moveably between the opening and the space. The gate to/from radiation shielded regions is closed and radiation is shielded by closing the shielding door. When entering into the radiation shielded regions by passing through the labyrinth, the shielding door is installed in the space of the radiation shielding wall. The shielding door shields the passage of radiation while being integrated with the wall of the labyrinth, and radiation released from the opening is attenuated by the labyrinth. Accordingly, even if human beings or products can pass the labyrinth and go in to and out of the radiation shielded regions. The shielding door is installed in the space of the radiation shielding wall even after opened, and does not hinder operations on the side of paths. (N.H.)

199

Novelty and change detection radiation physics experiments  

OpenAIRE

This thesis deals with the detection and analysis of low-level natural and induced radioactivity. Using high energy-resolution Ge detectors in low-level counting areas airborne radioactivity’s like Be-7 and Cs-137 have been investigated. The experimental facilities and techniques are described in some detail. One of the aims in this work is the studying of change detection in the amount of the activity received on the earth from events that happen at the solar system. Information about this...

Jabor, Abbas

2007-01-01

200

Apparatus and methods for detecting chemical permeation  

Science.gov (United States)

Apparatus and methods for detecting the permeation of hazardous or toxic chemicals through protective clothing are disclosed. The hazardous or toxic chemicals of interest do not possess the spectral characteristic of luminescence. The apparatus and methods utilize a spectrochemical modification technique to detect the luminescence quenching of an indicator compound which upon permeation of the chemical through the protective clothing, the indicator is exposed to the chemical, thus indicating chemical permeation.

Vo-Dinh, Tuan (Knoxville, TN)

1994-01-01

201

Nonlinear digital pulse processing for radiation detection systems  

International Nuclear Information System (INIS)

Full text: Real-time pulse pileup recovery: Radiation detectors are susceptible at high count-rates to a phenomenon called pulse pileup. Current digital pulse processing techniques rely on linear filtering methods, which reduce integration time in an attempt to improve throughput. This approach degrades the signal-to-noise ratio (SNR), and ultimately, energy resolution. Furthermore, a point is rapidly reached beyond which the majority of data is corrupted by pulse pileup. This paper details a pulse pileup recovery technology for processing the digitised output of radiation detection systems. Using a multi-stage, nonlinear digital signal processing algorithm this technology is able to decode multi-event pileup in real-time. The effect of pileup is almost entirely eliminated, enabling high count-rate operation with negligible deadtime, improved energy resolution and very high detector throughput. Figure 1 shows the algorithm output illustrating the ability of the technology to recover the component pulses in the input signal, even when the pulses are very closely spaced. The performance of the technology has been evaluated across a range of ultra-high count-rates using a digital nuclear pulse generator. The results indicate that over a 250-fold increase in input count-rate (from 10 kc/s to 2,500 kc/s) system throughput and energy resolution degrades by less than 10%

202

Automated Methods for Multiplexed Pathogen Detection  

Energy Technology Data Exchange (ETDEWEB)

Detection of pathogenic microorganisms in environmental samples is a difficult process. Concentration of the organisms of interest also co-concentrates inhibitors of many end-point detection methods, notably, nucleic acid methods. In addition, sensitive, highly multiplexed pathogen detection continues to be problematic. The primary function of the BEADS (Biodetection Enabling Analyte Delivery System) platform is the automated concentration and purification of target analytes from interfering substances, often present in these samples, via a renewable surface column. In one version of BEADS, automated immunomagnetic separation (IMS) is used to separate cells from their samples. Captured cells are transferred to a flow-through thermal cycler where PCR, using labeled primers, is performed. PCR products are then detected by hybridization to a DNA suspension array. In another version of BEADS, cell lysis is performed, and community RNA is purified and directly labeled. Multiplexed detection is accomplished by direct hybridization of the RNA to a planar microarray. The integrated IMS/PCR version of BEADS can successfully purify and amplify 10 E. coli O157:H7 cells from river water samples. Multiplexed PCR assays for the simultaneous detection of E. coli O157:H7, Salmonella, and Shigella on bead suspension arrays was demonstrated for the detection of as few as 100 cells for each organism. Results for the RNA version of BEADS are also showing promising results. Automation yields highly purified RNA, suitable for multiplexed detection on microarrays, with microarray detection specificity equivalent to PCR. Both versions of the BEADS platform show great promise for automated pathogen detection from environmental samples. Highly multiplexed pathogen detection using PCR continues to be problematic, but may be required for trace detection in large volume samples. The RNA approach solves the issues of highly multiplexed PCR and provides ''live vs. dead'' capabilities. However, sensitivity of the method will need to be improved for RNA analysis to replace PCR.

Straub, Tim M.; Dockendorff, Brian P.; Quinonez-Diaz, Maria D.; Valdez, Catherine O.; Shutthanandan, Janani I.; Tarasevich, Barbara J.; Grate, Jay W.; Bruckner-Lea, Cindy J.

2005-09-01

203

Elastooptical antenna for detection of gravitational radiation.  

Science.gov (United States)

Using the photoelastic effect in transparent solids to detect stresses induced by a gravitational wave is proposed. The induced birefringence is measured by a polarimeter. The phase difference is amplified by a Fabry-Perot cavity containing the medium. The sensitivity of this optical strain sensor is discussed, and that of the antenna is estimated. PMID:20216858

Boyer, G R; Lamouroux, B F; Prade, B S; Vinet, J Y

1980-02-01

204

High sensitivity leak detection method and apparatus  

Science.gov (United States)

An improved leak detection method is provided that utilizes the cyclic adsorption and desorption of accumulated helium on a non-porous metallic surface. The method provides reliable leak detection at superfluid helium temperatures. The zero drift that is associated with residual gas analyzers in common leak detectors is virtually eliminated by utilizing a time integration technique. The sensitivity of the apparatus of this disclosure is capable of detecting leaks as small as 1.times.10.sup.-18 atm cc sec.sup.-1.

Myneni, Ganapatic R. (Grafton, VA)

1994-01-01

205

Development of radiation detection and measurement system - Development of scintillation radiation sensor  

Energy Technology Data Exchange (ETDEWEB)

We have been fabricated CsI(Tl) scintillation crystals and plastic scintillators for radiation-based measuring equipment. CsI (Tl) single crystals doped with thallium as an activator were grown using the Czochralski method. The crystal structure of grown CsI(Tl) was bcc, and it was confirmed that its lattice constant was 4,568 A. The spectral range of luminescence of CsI(Tl) was 350 {approx} 700 nm independent of thallium concentration, and the fast component of the luminescence was decreased with increasing thallium concentration. The energy resolution of CsI(Tl) scintillator doped with 0.1 mole% thallium was about 9% for 137 Cs {gamma}-rays. The relation formula of {gamma}-ray energy versus energy resolution was ln(FWHM%)=-0.705ln({epsilon})+6.75. The radiation damage of CsI(Tl) increased in proportion to thallium concentration and radiation damage of CsI(Tl) increased in proportion to thallium concentration and radiation dosage, and the irradiated crystals were colored reddish. The radiation induced absorption bands appeared around 355, 425, 520 and 555 nm, and their energy level were about 3.50, 2.88, 2.39 and 2.21 eV. Plastic scintillators were fabricated thermal polymerization method. Those were polymerizing at 120 deg. C, during 72 hours, and annealing at 75 deg. C, during 24 hours. When the concentration of 1st solute was 1.5 wt% and concentration of 2nd solute was 0.01 wt%, the characteristics of scintillation were very excellent. Also 3.0 wt% tetraphenyl lead were loaded to improve the detection efficiency of {gamma}-ray. The range of emission spectrum was 400 {approx} 450nm, and the central peak was 415 nm. The radiation damage was not appear under 1*10{sup 3}Gy, but the color of plastic scintillator was changed to brown, over 1*10{sup 4}Gy exposured. 84 refs., 39 figs. (Author)

Kang, Hee Dong; Kim, Wan [Kyungpook National University, Taegu (Korea); Kim, Do Sung [Taegu University, Taegu (Korea)

2000-03-01

206

Solid state nuclear track detection principles, methods and applications  

CERN Document Server

Solid State Nuclear Track Detection: Principles, Methods and Applications is the second book written by the authors after Nuclear Tracks in Solids: Principles and Applications. The book is meant as an introduction to the subject solid state of nuclear track detection. The text covers the interactions of charged particles with matter; the nature of the charged-particle track; the methodology and geometry of track etching; thermal fading of latent damage trails on tracks; the use of dielectric track recorders in particle identification; radiation dossimetry; and solid state nuclear track detecti

Durrani, S A; ter Haar, D

2013-01-01

207

Spherical harmonics methods for thermal radiation transport  

Science.gov (United States)

An implicit, spherical harmonic (Pn) method for solving thermal transport problems is developed. The method uses a high resolution Riemann solver to produce an upwinded discretization. The high resolution scheme introduces nonlinearities to the radiation transport operator to avoid the creation of artificial oscillations in the solution. By using a minmod limiter a quasi-linear approach to solving this nonlinear system of equations is developed. Through analysis and numerical results it is shown that the quasi-linear approach does suppress artificial oscillations and gives better than first order accuracy and is less computationally demanding than a fully nonlinear solve. The time integration methods considered are the backward Euler method and a high resolution time integration method. Also, reflecting boundary conditions for the Pn equations in three-dimensions are presented. It is shown that the standard Riemann solver is not robust in the diffusion limit. A fix is suggested that scales out the dissipation added by the Riemann solver as spatial cells become optically thick. The Green's function for the one-dimensional P 1 thermal transport equations with Cv ? T3 is derived. The Green's function is used to create the P1 solution to a common benchmark and to a problem of an infinite, pulsed line source. The implicit method was able to produce robust results to thermal transport problems in one and two dimensions. The implicit approach allowed the numerical method to take times steps on the longer material energy time scale rather than the speed of light time scale. In two dimensional problems the Pn solutions contained negative radiation energy densities. These negatives caused the material temperature to become negative as well. The free-streaming limit of the Pn equations is explored and it is shown why in transient problems in multiple-dimensions the Pn solutions can have negative energy densities.

McClarren, Ryan G.

208

Development of radiation detection and measurement systems  

International Nuclear Information System (INIS)

This report contains descriptions on the following six items. The first item is the result of a study on CsI(TI) crystals with their light emitting characteristics and the result of a study on plastic scintillators. The second item is the result of a study on advanced radiation detectors and includes experiments for the effect of using a Compton suppressor with an HPGe detector. For the third item, we describe the results of a design work done using EGS4 for a thickness gauge, a density gauge, and a level gauge. The fourth item contains descriptions on the prototype circuit systems developed for a level gauge, a thickness gauge, and for a survey meter. The fifth part contains the computed tomography algorithm and a prototype scanning system developed for a CT system. As the sixth and the last item, we describe the prototype high precision heat source and the prototype heat-voltage converter which we have designed and fabricated

209

Injury detecting method by eddy current  

International Nuclear Information System (INIS)

The present invention provides a highly accurate testing device for maintenance and detection of heat transfer pipes of a heat exchanger. Namely, in an injury detection test by using eddy current injuries of tubular materials are detected by inserting a testing probe formed by winding coils around a cylindrical coil bobbin to the inside of the tube, supplying DC-current to the coils and detecting the injuries by utilizing the eddy current generated in the tube. In a self-comparing type injury detection testing method by using eddy current, a difference between impedance changes of two coils disposed in adjacent with each other is taken out. In a testing coils using two coils are wound in a triangular waveform, and one of the coils is disposed to the other while being displaced by a length corresponding to 1/4 of the pitch of the waveform. With such a constitution, injuries of the tubular material in the circumference direction, which could not be detected so far, can be detected without worsening the performance of the self-comparing method and not increasing the length of the coil than required. In order to wind the coils in the complicated waveform, protruded guide is formed on the coil bobbin, not by using the existent method of disposing grooved guides on the coil bobbin. (I.S.)

210

Radiation-induced thermal noise in optoacoustic detection cells  

International Nuclear Information System (INIS)

When radiation is strongly absorbed in an optoacoustic detection cell, fluctuations in the radiation intensity give rise to thermal noise within the cell. The spectral density of the thermal noise thus generated is dependent on both the frequency response of the cell and the power spectral density of the radiation source. The frequency response function for the spectrophone cell is determined by application of elementary linear response theory to a solution of the heat equation for a uniformly heated cylinder. The power spectral density of coherent and incoherent radiation sources can be determined from their respective intensity autocorrelation functions. Radiation sources are discussed with regard to obtaining the smallest root-mean-square temperature fluctuations in the spectrophone cell. It is shown that optoacoustic noise is minimized by using a stabilized laser operating well above threshold. 15 references, 1 figure, 1 table

211

A biodosemeter that utilises isolated enzymes to detect ionising radiation  

International Nuclear Information System (INIS)

The development of a biosensor for the detection of ionising radiation (biodosemeter) utilising the advantageous properties of the photosystem II (PSII) complex and its response to ionising radiation is reported. The transducer signal for this biosensor can be fluorescence, which is dependent on photosynthetic activity. Exposure of biological material to ionising radiation leads to a loss of function due to the destruction of critical structures. Radiation target theory predicts an exponential decrease in biochemical activity that is dependent on the absorbed radiation energy and directly proportional to the mass of the individual molecules possessing this activity. The activity is lost whenever the protein is hit since very high energy is transferred through the chain. Several approaches were used to optimise the immobilisation of PSII complexes to improve the sensitivity of the biodosemeter. (author)

212

Eye blinking-based method for detecting driver drowsiness.  

Science.gov (United States)

Drowsy driving is a major cause of traffic accidents. Eye blinking is considered as important evidence of driver drowsiness. In this paper, a portable and low cost device for monitoring a driver's drowsiness is proposed. The proposed system consists of two main parts that detect eye blinking based on IR sensors mounted on eyewear. Depending on the reflected and absorbed IR radiation, this system detects and classifies the eye blinking into normal blinking (NB) or prolonged blinking (PB). The detected prolonged blinking is used to trigger an audio/visual alarm system which draws the driver's attention back. The system was simulated initially by LabVIEW® software. Moreover, the system was bench tested on 15 adult volunteers; eye blinking were detected and classified successfully for all subjects. The results of this research are promising and additional investigation is required to further improve the method. PMID:25340719

Ma'touq, Jumana; Al-Nabulsi, Jamal; Al-Kazwini, Akeel; Baniyassien, Ahmed; Al-Haj Issa, Ghassan; Mohammad, Haitham

2014-11-01

213

Simulated performance of a position sensitive radiation detecting system (COCAE)  

CERN Document Server

Extensive simulations of a portable radiation detecting system have been performed in order to explore important performance parameters. The instrument consists of a stack of ten detecting layers made of pixelated Cadmium Telluride (CdTe) crystals. Its aim is to localize and identify radiation sources, by exploiting the Compton imaging technique. In this paper we present performance parameters based on simulation studies. Specifically the ratio of incompletely absorbed photons, the detector's absolute efficiency as well as its energy and angular resolution are evaluated in a wide range of incident photon energies.

Karafasoulis, K; Seferlis, S; Kaissas, I; Lambropoulos, C; Loukas, D; Poritiriadis, C

2011-01-01

214

Apparatus for detecting ionizing radiation while correcting distortion  

International Nuclear Information System (INIS)

The invention relates to cameras for detecting the ionizing radiation of radioactive isotopes, also known as 'scintillation', 'Anger' or 'nuclear' cameras, and especially to an electric circuit for correcting distortion due to photomultiplier tube spacing and arrangement, and to the distance between the tube array and the scintillation plate. The invention is described in relation to a radiation-sensitive camera; however, it should be noted that the invention has other applications in areas where distortion results from the non-linear response of a photomultiplier tube arrangement or other detection devices

215

Lattice Boltzmann method for one-dimensional radiation transfer.  

Science.gov (United States)

The macroscopic conservation equations of radiation energy and radiation momentum are derived on the basis of radiation hydrodynamics. Based on the Chapman-Enskog method, the lattice Boltzmann model for one-dimensional radiative transfer is proposed from the Boltzmann equation. The numerical simulation results agree well with the exact solution and show that the lattice Boltzmann method developed in this paper has good accuracy and stability for solving one-dimensional radiative transfer problems. PMID:21867340

Ma, Yu; Dong, ShiKui; Tan, HePing

2011-07-01

216

Anti noise system and method using broadband radiation modes  

OpenAIRE

Anti noise system and method, in particular for suppressing sound radiated from a structure, using a formulation of the most efficiently radiating vibration patterns of a vibrating body, the radiation modes, in the time domain. The radiation modes can be used to arrive at efficient weighting schemes for an array of sensors in order to reduce controller dimensionality. The particular radiation modes are determined on the basis of broadband signals. A method is given to obtain these modes from ...

Berkhoff, Arthur Perry

2005-01-01

217

Radiation detection technique on the fishery foods  

Energy Technology Data Exchange (ETDEWEB)

When muscles and myofibril are irradiated by gamma ray, Mg-ATPase activity increased with increasing of dose, but EDTA-ATPase decreased. If dose is very large, Ca-ATPase activity increased. The effects of state of protein on these phenomena were investigated. The muscles, myofibril and myosin B of Tilapia nilotica were used as samples. Change of Ca-ATPase, Mg-ATPase and EDTA-ATPase activity of myosin B by gamma-ray irradiation was the same as myofibril and muscles, but myosin B showed high sensitivity and each ATPase activity was changed by low dose. Accordingly, these values were more difficult to apply to detection technique of irradiation than state of muscle and myofibril. Collagen is known to degenerate and coagulate by gamma-ray irradiation. However, amount of hot water soluble collagen was increased with increasing of dose. (S.Y.)

Nakamura, Koji; Yano, Yutaka; Oikawa, Hiroshi [National Research Inst. of Fisheries Science, Yokohama (Japan)

2000-02-01

218

Overview and Benchmarking of Motion Detection Methods  

OpenAIRE

In this chapter, we provide an overview of the most highly cited motion detection meth- ods. We identify the most commonly used background models together with their features, the kind of updating scheme they use, some spatial aggregation models as well as the most widely used post-processing operations. We also provide an overview of datasets used to validate motion detection methods. Please note that this literature review is by no means exhaustive and thus we provide a list ...

Jodoin, Pierre-marc; Pierard, Se?bastien; Wang, Yi; Droogenbroeck, Marc

2014-01-01

219

Detection of irradiated meats by hydrocarbon method  

International Nuclear Information System (INIS)

Meats, for example, lamb, razorback, wild duck and turkey were irradiated by gamma ray, and the amounts of hydrocarbons formed from fatty acids were measured. Since C20:0 was found from wild duck and turkey. C1-18:1 was recommended for internal standard. Good correlation was found between the amount of hydrocarbons and the doses of gamma irradiation. This study shows that such hydrocarbons induced after radiation procedure as C1,7-16:2, C8-17:1, C1-14:1, and C15:0 may make it possible to detect irradiated lamb, razorback, wild duck and turkey. (author)

220

Conducted and radiated noise in detection devices  

International Nuclear Information System (INIS)

Conducted and radiated noise is an external noise which affects the quality of the signals of the detectors. An external noise can be reduced, usually, by shielding. This was the situation with 'older fashion' devices which uses boxes and coaxial cables. As the devices becomes more complex, the shielding of the detectors is more and more difficult and the transmission lines evolves from coaxial cables to twisted pair cables which are no more shielded. In such situation, the conducted and radiated noise (C and R noise) becomes important. Due to complexity of a real detector, the main work is based on experiments with components and simulations of some specific problems, associated with CDC detector. The first experiment was done to understand how the C and R noise is propagated. The emission device was a set of coils (between 3 and 5 turns with diameter from 10 to 50 mm) feed by an 74S140 driver. A pulse of about 8 ns width was generated. A coil of reception of about the same physical characteristics was used to see the emitted pulse. When the two coils are separated by about 80 cm, the receiver generated no signal. But, if along the two coils, a conductive material is introduced (a wire for instance), the receiver senses a signal. This signal is not changed too much if the wire is or not connected to ground. The explanation is simple: the pulse in the emitting coil produces an EM pulse which spreads in space. If a conductive material is around, the EM energy is receivaterial is around, the EM energy is received by that conductor and it is propagated at tens of meters with small attenuation. When this energy reaches the end of the conductor, it is radiated in space. If some other conductors are around, the energy is received and propagated by that conductors. This experiment was done for about 20 kinds of conductors (different coax cables, twisted-pair ribbons, power cables, metallic bars) and with many coils (different diameters and numbers of turns). It was measured the pk-to-pk level, decay constant and frequencies of oscillations (eigen frequencies). Because a Fourier analyzer was not available, the eigen-frequencies were just evaluated by the oscilloscope. The conclusions are: 1. For a 8 ns width pulse, the oscillation is damped in time with a constant between about 100 ns for cooper bars and double-shielded coaxes and up to around 600 ns for twisted-pair ribbons; 2. The frequency of these oscillations depends on the conductor under test and so they are eigen-frequencies of that conductor. For a RG 59BU cable (F and G) the dominant EF was 20 MHZ as for the same RG59U (Amphenol) the EF was 69 MHZ. This is so because the technology to make the shielding is different. For a cooper bar for instance EF was measures as 46 MHz for 3.7 mm diameter and 26 MHz for 2.35 mm diameter. To understand if these EM pulses which propagate everywhere are important or not we have to remind that these pulses propagate on the surface of the conductors. For a shielded coax, they cannot go inside to change the signal. The situation in totally different when such pulse reaches a twisted-pair cable. The signal is superimposed on the useful signal and is propagated as a 'normal' signal. For this situation, the receiver of a twisted pair cable is differential so that the common mode signal could be rejected by a proper designed receiver. This is so only at the receiver side. If such noise propagates toward the source of signal (the output of the preamplifier for instance), when this EM energy goes inside the transmitter, the electronic device reacts at these EM pulses. Its reaction can be a signal which goes back to line and this is impossible to be rejected by receiver because is like a normal differential signal. For a user it looks like being generated by the detector. In an experiment, a real preamplifier, a real ribbon (about 5 meter long) and a real receiver were connected on a table. An 8 ns pulse was inserted somewhere on that 5 meter twisted-pair cable and the signal on the receiver was monitored. The input of the preamplifier was conne

221

Method for decontaminating radiation metal waste  

International Nuclear Information System (INIS)

This report describes a method for decontaminating radiation metal waste characterized by the following properties: in order to decontaminate radiation metal waste of various shapes produced by facilities involved with radioactive substances, non-complex shapes are decontaminated by electropolishing the materials in a neutral saline solution. Complex shapes are chemically decontaminated by means of an acid solution containing permanganic acid or an alkaline solution and a mineral acid solution. After neutralizing the solutions used for chemical decontamination, the radioactive material is separated and removed. Further, in the decontamination method for radioactive metal waste, a supernatant liquid is reused as the electrolyte in electropolishing decontamination. Permanganic ions (MnO4-) are reduced to manganese dioxide (MnO2) and deposited prior to neutralizing the solution used for chemical decontamination. Once manganese dioxide (MnO2) has been separated and removed, it is re-used as the electrolyte in electropolishing decontamination by means of a process identical to the separation process for radioactive substances. 3 figs

222

The problem of the detection threshold in radiation measurement  

International Nuclear Information System (INIS)

In all cases encountered in practical radiation measurement, the basic problem is to differentiate between the lowest measured value and the zero value (background, natural background radiation, etc.). For this purpose, on the mathematical side, tests based on hypotheses are to be applied. These will show the probability of differentiation between two values having the same random spread. By means of these tests and the corresponding error theory, a uniform treatment of the subject, applicable to all problems relating to measuring technique alike, can be found. Two basic concepts are found in this process, which have to be defined in terms of semantics and nomenclature: Decision threshold and detection threshold, or 'minimum detectable mean value'. At the decision threshold, one has to decide (with a given statistical error probability) whether a measured value is to be attributed to the background radiation, accepting the zero hypothesis, or whether this value differs significantly from the background radiation (error of 1rst kind). The minimum detectable mean value is the value which, with a given decision threshold, can be determined with sufficient significance to be a measured value and thus cannot be mistaken as background radiation (alternative hypothesis, error of 2nd kind). Normally, the two error types are of equal importance. It may happen, however, that one type of error gains more importance, depending on the approach. (orig.)oach. (orig.)

223

Self-occluding quad NaI directional gamma radiation detector for standoff radiation detection  

Science.gov (United States)

Currently there is a significant amount of interest in standoff radiation detection. One of the biggest challenges is to separate small radiation signals from large varying background radiation. Many systems have been developed to address this problem that rely on coded-aperture and/or Compton imaging. These imaging systems tend to be large, heavy, complex, and therefore expensive. In this paper we report on the development of a self-occluding directional gamma radiation sensor that is relatively small (cost, weight, and complexity. An azimuth can be resolved with a standard deviation of 7° in 10 seconds for a source yielding 45 CPS at the detector in a 300 CPS background radiation field. This paper describes the self-occluding quad NaI directional gamma radiation detector, the impact of gamma energy and distance on angular precision and accuracy, and potential applications.

Portnoy, David; Mattson, John

2011-09-01

224

Direct electron detection methods in electron microscopy  

International Nuclear Information System (INIS)

New types of low-noise electronic detection methods for biological high-resolution cryo-electron microscopy are essential to cope with large volumes of data. We discuss the use of direct detection methods in silicon, avoiding intermediate steps, e.g. energy conversion to light in a phosphor as used in CCD-based detectors. We present very promising results obtained with 60 and 120 keV electrons in a hybrid silicon pixel detector, Medipix1, containing 64x64 pixels, each 170 ?m2. The main advantages of this technique over phosphor-based CCDs are in improved spatial resolution and faster, noiseless readout

225

Direct electron detection methods in electron microscopy  

Energy Technology Data Exchange (ETDEWEB)

New types of low-noise electronic detection methods for biological high-resolution cryo-electron microscopy are essential to cope with large volumes of data. We discuss the use of direct detection methods in silicon, avoiding intermediate steps, e.g. energy conversion to light in a phosphor as used in CCD-based detectors. We present very promising results obtained with 60 and 120 keV electrons in a hybrid silicon pixel detector, Medipix1, containing 64x64 pixels, each 170 {mu}m{sup 2}. The main advantages of this technique over phosphor-based CCDs are in improved spatial resolution and faster, noiseless readout.

Faruqi, A.R. E-mail: arf@mrc-lmb.cam.ac.uk; Cattermole, D.M.; Raeburn, C

2003-11-01

226

Radiation source localization device, using variable collimation detection means  

International Nuclear Information System (INIS)

The device is also made up of collimation adjustment means, a camera giving a zone image, means to make the camera shot axis meet with the detection solid angle axis, and means to form a zone image focussed on the shot axis, and a circle (C) superposed on this image, centred on this axis and corresponding to the intersection of the detection solid angle with the plane of the observed scene, and to give a piece of information on the detected radiation intensity in this solid angle. (Author). 2 figs., 3 refs

227

A Bayesian method for detecting stellar flares  

CERN Document Server

We present a Bayesian-odds-ratio-based algorithm for detecting stellar flares in light curve data. We assume flares are described by a model in which there is a rapid rise with a half-Gaussian profile, followed by an exponential decay. Our signal model also contains a polynomial background model. This is required to fit underlying light curve variations that are expected in the data, which could otherwise partially mimic a flare. We characterise the false alarm probability and efficiency of this method and compare it with a simpler thresholding method based on that used in Walkowicz et al (2011). We find our method has a significant increase in detection efficiency for low signal-to-noise ratio (S/N) flares. For a conservative false alarm probability our method can detect 95% of flares with S/N less than ~20, as compared to S/N of ~25 for the simpler method. As an example we have applied our method to a selection of stars in Kepler Quarter 1 data. The method finds 687 flaring stars with a total of 1873 flares...

Pitkin, M; Fletcher, L; Grant, S D T

2014-01-01

228

Evaluation of potassium nitrate for gamma-radiation detection  

International Nuclear Information System (INIS)

Pellets of potassium nitrate (KNO3) were evaluated to verify if they can be employed as dosimetric material for high dose measurements in routine use of radiation monitoring in radiation processing plants. The spectrophotometry in the visible region was used as detection technique. Pellets of KNO3 were dissolved in pure water to allow the optical absorption measurements before and after irradiation with 60 Co gamma radiation source, calibrated with Fricke solution reference dosimeter. The absorption spectrum of the KNO3 solution was investigated in the wavelength region between 500 and 600 nm to determine the maximum absorption wavelength. Dosimetric properties such as dose rate dependence in the interval between 0.059 and 3.82 kGy/h, angular radiation incidence dependence between 0 and 90 degrees and dose response in the range between 1-150 kGy were investigated. The obtained results show the proposed dosimetric material can be useful in high dose measurements. (author)

229

Metagenomic Detection Methods in Biopreparedness Outbreak Scenarios  

DEFF Research Database (Denmark)

In the field of diagnostic microbiology, rapid molecular methods are critically important for detecting pathogens. With rapid and accurate detection, preventive measures can be put in place early, thereby preventing loss of life and further spread of a disease. From a preparedness perspective, early detection and response are important in order to minimize the consequences. During the past 2 decades, advances in next-generation sequencing (NGS) technology have changed the playing field of molecular methods. Today, it is within reach to completely sequence the total microbiological content of a clinical sample, creating a metagenome, in a single week of laboratory work. As new technologies emerge, their dissemination and capacity building must be facilitated, and criteria for use, as well as guidelines on how to report results, must be established. This article focuses on the use of metagenomics, from sample collection to data analysis and to some extent NGS, for the detection of pathogens, the integration of the technique in outbreak response systems, and the risk-based evaluation of sample processing in routine diagnostics labs. The article covers recent advances in the field, current debate, gaps in research, and future directions. Examples of metagenomic detection, as well as possible applications of the methods, are described in various biopreparedness outbreak scenarios.

Karlsson, Oskar Erik; Hansen, Trine

2013-01-01

230

Methods of leak detection in chemical plants  

International Nuclear Information System (INIS)

Leak detection in chemical plants is necessary for two reasons: a) for the manufacture of products of high quality an purity, b) to prevent the release of substances dangerous to the environment. Leak tests are carried out on welded seams of chemical apparatus, valves and fittigs, flanges, seals on reciprocating and rotary pumps and on agitators. The leak detection methods being used at present range from the simple air and liquid pressure test to the test gas method using gases containing halogens an helium. The DECHEMA-working group 'Non-destructive test methods in chemical plants' has made a thorough examination of the subject an has published an information paper with guidelines for the selection of test methods (with 4 supplements for practical application). (orig.)

231

ANOLE Portable Radiation Detection System Field Test and Evaluation Campaign  

Energy Technology Data Exchange (ETDEWEB)

Handheld, backpack, and mobile sensors are elements of the Global Nuclear Detection System for the interdiction and control of illicit radiological and nuclear materials. They are used by the U.S. Department of Homeland Security (DHS) and other government agencies and organizations in various roles for border protection, law enforcement, and nonproliferation monitoring. In order to systematically document the operational performance of the common commercial off-the-shelf portable radiation detection systems, the DHS Domestic Nuclear Detection Office conducted a test and evaluation campaign conducted at the Nevada Test Site from January 18 to February 27, 2006. Named “Anole,” it was the first test of its kind in terms of technical design and test complexities. The Anole test results offer users information for selecting appropriate mission-specific portable radiation detection systems. The campaign also offered manufacturers the opportunity to submit their equipment for independent operationally relevant testing to subsequently improve their detector performance. This paper will present the design, execution, and methodologies of the DHS Anole portable radiation detection system test campaign.

Chris A. Hodge

2007-07-12

232

ANOLE Portable Radiation Detection System Field Test and Evaluation Campaign  

International Nuclear Information System (INIS)

Handheld, backpack, and mobile sensors are elements of the Global Nuclear Detection System for the interdiction and control of illicit radiological and nuclear materials. They are used by the U.S. Department of Homeland Security (DHS) and other government agencies and organizations in various roles for border protection, law enforcement, and nonproliferation monitoring. In order to systematically document the operational performance of the common commercial off-the-shelf portable radiation detection systems, the DHS Domestic Nuclear Detection Office conducted a test and evaluation campaign conducted at the Nevada Test Site from January 18 to February 27, 2006. Named 'Anole', it was the first test of its kind in terms of technical design and test complexities. The Anole test results offer users information for selecting appropriate mission-specific portable radiation detection systems. The campaign also offered manufacturers the opportunity to submit their equipment for independent operationally relevant testing to subsequently improve their detector performance. This paper will present the design, execution, and methodologies of the DHS Anole portable radiation detection system test campaign

233

Quantitative boron detection by neutron transmission method  

International Nuclear Information System (INIS)

//Quantitative boron detection is mainly performed by chemical methods like colorimetric titration. High neutron absorption cross section of natural boron makes attractive its detection by absorption measurements. This work is an extension of earlier investigations where neutron radiography technique was used for boron detection. In the present investigation, the neutron absorption rate of boron containing solutions is the way to measure quantitatively the boron content of the solutions. The investigation was carried out in Istanbul TRIGA Mark-II reactor. In the end of the experiments, it was observed that even |ppw| grade boron in aqueous solution can be easily detected. The use of this method is certainly very useful for boron utilizing industries like glass and steel industries.The major disadvantage of the method is the obligation to use always aqueous solutions to be able to detect homogeneously the boron content. Then, steel or glass samples have to be put first in an appropriate solution form. The irradiation of steel samples can give the distribution of boron by the help of a imaging and this suggested method will give its quantitative measurement. The superiority of this method are its quick response time and its accuracy. To test this accuracy, a supposed unknown , solution of boric acid is irradiated and then calculated by the help of the calibration curve. The measured value of boric acid was 0.89 mg and the calculated value was found to be 0.98 mg which gives an accuracy of 10 %. It was also seen that the method is more accurate for low concentration. (authors)

234

Method for the detection of aquaretic compounds  

DEFF Research Database (Denmark)

Disclosed is a method for detecting an aquaretic compound. In one embodiment, the method includes administering to a mammal a candidate compound that modulates a nociceptin receptor. Biological material is isolated from the mammal and expression of aquaporin-2 is measured. Modulation of the aquaporin-2 is taken to be indicative of a candidate compound having aquaretic activity. The invention has a wide spectrum of uses including helping to identify new diuretics that spare unwanted loss of sodium and potassium ions.

Jonassen, Thomas unknown

235

GMDD: a database of GMO detection methods  

OpenAIRE

Abstract Background Since more than one hundred events of genetically modified organisms (GMOs) have been developed and approved for commercialization in global area, the GMO analysis methods are essential for the enforcement of GMO labelling regulations. Protein and nucleic acid-based detection techniques have been developed and utilized for GMOs identification and quantification. However, the information for harmonization and standardization of GMO analysis methods at globa...

Guo Rong; Liang Wanqi; Jp, Marvin Hans; Kleter Gijs A; Shen Kailin; Kim Banghyun; Yang Litao; Dong Wei; Zhang Dabing

2008-01-01

236

Fuel rod failure detection method and system  

International Nuclear Information System (INIS)

The inventor claims a method for the detection of a defective fuel rod cladding tube or of inleaked water in the cladding tube of a fuel rod in the fuel assembly of a pressurized-water reactor. The fuel assembly is not disassembled but examined as a whole. In the examination, the cladding tube is heated near one of its two end plugs, e.g. with an attached high-frequency inductor. The water contained in the cladding tube evaporates, and steam bubbles or a condensate are detected by the ultrasonic impulse-echo method. It is also possible to measure the delay of the temperature rise at the end plug or to determine the cooling energy required to keep the end plug temperature stable and thus to detect water ingression. (DG/AK)

237

Radioimmunoassay method for detection of gonorrhea antibodies  

International Nuclear Information System (INIS)

A novel radioimmunoassay for the detection of gonorrhea antibodies in serum is described. A radionuclide is bound to gonorrhea antigens produced by a growth culture. In the presence of gonorrhea antibodies in the serum, an antigen-antibody conjugate is formed, the concentration of which can be measured with conventional radiometric methods. The radioimmunoassay is highly specific

238

Method for detecting gas turbine engine flashback  

Science.gov (United States)

A method for monitoring and controlling a gas turbine, comprises predicting frequencies of combustion dynamics in a combustor using operating conditions of a gas turbine, receiving a signal from a sensor that is indicative of combustion dynamics in the combustor, and detecting a flashback if a frequency of the received signal does not correspond to the predicted frequencies.

Singh, Kapil Kumar; Varatharajan, Balachandar; Kraemer, Gilbert Otto; Yilmaz, Ertan; Lacy, Benjamin Paul

2012-09-04

239

Radiation Detection Scenario Analysis Toolbox (RADSAT) Test Case Implementation Final Report  

Energy Technology Data Exchange (ETDEWEB)

Final report for the project. This project was designed to demonstrate the use of the Radiation Detection Scenario Analysis Toolbox (RADSAT) radiation detection transport modeling package (developed in a previous NA-22 project) for specific radiation detection scenarios important to proliferation detection.

Shaver, Mark W.

2010-09-27

240

Passive radiation detection using optically active CMOS sensors  

Science.gov (United States)

Recently, there have been a number of small-scale and hobbyist successes in employing commodity CMOS-based camera sensors for radiation detection. For example, several smartphone applications initially developed for use in areas near the Fukushima nuclear disaster are capable of detecting radiation using a cell phone camera, provided opaque tape is placed over the lens. In all current useful implementations, it is required that the sensor not be exposed to visible light. We seek to build a system that does not have this restriction. While building such a system would require sophisticated signal processing, it would nevertheless provide great benefits. In addition to fulfilling their primary function of image capture, cameras would also be able to detect unknown radiation sources even when the danger is considered to be low or non-existent. By experimentally profiling the image artifacts generated by gamma ray and ? particle impacts, algorithms are developed to identify the unique features of radiation exposure, while discarding optical interaction and thermal noise effects. Preliminary results focus on achieving this goal in a laboratory setting, without regard to integration time or computational complexity. However, future work will seek to address these additional issues.

Dosiek, Luke; Schalk, Patrick D.

2013-05-01

241

Delay-Line Three-Dimensional Position Sensitive Radiation Detection  

Science.gov (United States)

High-resistivity silicon(Si) in large volumes and with good charge carrier transport properties has been produced and achieved success as a radiation detector material over the past few years due to its relatively low cost as well as the availability of well-established processing technologies. One application of that technology is in the fabrication of various position-sensing topologies from which the incident radiation's direction can be determined. We have succeeded in developing the modeling tools for investigating different position-sensing schemes and used those tools to examine both amplitude-based and time-based methods, an assessment that indicates that fine position-sensing can be achieved with simpler readout designs than are conventionally deployed. This realization can make ubiquitous and inexpensive deployment of special nuclear materials (SNM) detecting technology becomes more feasible because if one can deploy position-sensitive semiconductor detectors with only one or two contacts per side. For this purpose, we have described the delay-line radiation detector and its optimized fabrication. The semiconductor physics were simulated, the results from which guided the fabrication of the guard ring structure and the detector electrode, both of which included metal-field-plates. The measured improvement in the leakage current was confirmed with the fabricated devices, and the structures successfully suppressed soft-breakdown. We also demonstrated that fabricating an asymmetric strip-line structure successfully minimizing the pulse shaping and increases the distance through which one can propagate the information of the deposited charge distribution. With fabricated delay-line detectors we can acquire alpha spectra (Am-241) and gamma spectra (Ba-133, Co-57 and Cd-109). The delay-line detectors can therefore be used to extract the charge information from both ion and gamma-ray interactions. Furthermore, standard charge-sensitive circuits yield high SNR pulses. The detectors and existing electronics can therefore be used to yield imaging instruments for neutron and gamma-rays, in the case of silicon. For CZT, we would prefer to utilize current sensing to be able to clearly isolate the effects of the various charge-transport non-idealities, the full realization of which awaits the fabrication of the custom-designed TIA chip.

Jeong, Manhee

242

Investigation of antiques with radiation methods  

International Nuclear Information System (INIS)

The authenticity of three European medieval swords had to be proven. In addition, the production techniques used by the medieval smiths were studied. For the assessment of antiques and objects of art, both examination of the material and stylistic studies are required in nearly all cases. In most of these cases, not only one but several essentially different investigation methods have to be applied during the study of the material. Nuclear and radiation techniques are favoured, primarily because these can frequently be carried out non-invasively, which is essential in the study of objects of high value, since taking samples from the objects might devalue them significantly. Using nuclear techniques such as neutron activation analysis (NAA) or photon activation analysis (PAA), large volumes of material can be analysed in many cases, so it is possible to investigate the entire body of the object or large parts of it. Thus meaningful results with a high degree of representativeness can be obtained nondestructively. In activation analysis, the material under study is exposed to irradiation by subatomic particles - neutrons, photons, protons, etc. During bombardment with these, radioactive nuclides are produced through nuclear reactions. The radionuclides decay by emission of different types of radiation. Among these, photons (? or characteristic X rays) are preferred for use in analytical evaluation. The energy distribution of X and ? rays is characteristic for each radnd ? rays is characteristic for each radionuclide. Measured with an appropriate spectrometer, the spectra can be used for simultaneous multicomponent analyses. Since the method is based upon nuclear reactions, only the element composition can be determined; normally no chemical speciation is possible

243

Current Trends in Gamma Radiation Detection for Radiological Emergency Response  

Energy Technology Data Exchange (ETDEWEB)

Passive and active detection of gamma rays from shielded radioactive materials, including special nuclear materials, is an important task for any radiological emergency response organization. This article reports on the current trends and status of gamma radiation detection objectives and measurement techniques as applied to nonproliferation and radiological emergencies. In recent years, since the establishment of the Domestic Nuclear Detection Office by the Department of Homeland Security, a tremendous amount of progress has been made in detection materials (scintillators, semiconductors), imaging techniques (Compton imaging, use of active masking and hybrid imaging), data acquisition systems with digital signal processing, field programmable gate arrays and embedded isotopic analysis software (viz. gamma detector response and analysis software [GADRAS]1), fast template matching, and data fusion (merging radiological data with geo-referenced maps, digital imagery to provide better situational awareness). In this stride to progress, a significant amount of interdisciplinary research and development has taken place–techniques and spin-offs from medical science (such as x-ray radiography and tomography), materials engineering (systematic planned studies on scintillators to optimize several qualities of a good scintillator, nanoparticle applications, quantum dots, and photonic crystals, just to name a few). No trend analysis of radiation detection systems would be complete without mentioning the unprecedented strategic position taken by the National Nuclear Security Administration (NNSA) to deter, detect, and interdict illicit trafficking in nuclear and other radioactive materials across international borders and through the global maritime transportation–the so-called second line of defense.

Mukhopadhyay, S., Guss, P., Maurer, R.

2011-09-01

244

Detection of microwave radiation on porous silicon nanostructures  

Science.gov (United States)

We report on possibility to detect pulsed microwave radiation across the metal/oxide/porous silicon structures and analyse possible physical reasons causing the rise of the emf voltage signal. The n-type porous layers were fabricated according to conventional electrochemical etching procedure, and were exposed to pulsed 10 GHz microwave radiation. The results of investigation show that the porous Si samples have higher by at least one order voltage-to-power sensitivity than the samples without the porous layer, and are considered to have high potential to increase it further. Free carrier heating phenomenon is considered to be responsible for the signal formation.

Gradauskas, J.; Stupakova, J.; Sužied?lis, A.; Samuoliene, N.

2014-10-01

245

Detection of radiation from electrochemical cell intensifying beta decay.  

Science.gov (United States)

The predictions of relic neutrino existence and neutrino anomalous magnetic moment existence, as well as the solution of the Dirac equation for a neutral particle with an anomalous magnetic moment in the Coulomb field imply the existence of neutrino matter component. In this work the radiation intensifying (60)Co and (137)Cs beta decays by (0.42 ± 0.05)% and (0.160 ± 0.012)% has been detected from the end electrochemical cell. The radiation interaction cross-section with radioactive nuclei is more than 10(-30)cm(2). PMID:22728839

Muromtsev, V I; Veprev, D P

2012-08-01

246

ESR detection of black pepper using standard addition method  

International Nuclear Information System (INIS)

ESR techniques for studying the detection of radicals induced in gamma ray irradiated pepper were studied. The representative ESR spectrum of the pepper composed of a sextet centered at g=2.0, a single at the same g-value and a singlet at g=4.0. This reflects the evidence of three independent radicals in the pepper before irradiation. Upon gamma ray irradiation, a new pair of signals appeared. Using standard addition method for solid sample technique we prepared the experimental samples containing 2.0 - 20.0 w/w % irradiated black pepper. The progressive saturation behavior (PSB) at various microwave power levels indicated quite different relaxation behaviors of those signals. For the evaluation of radiation-induced radicals and irradiation effects we proposed a new protocol using the standard addition method. This would be called an advanced protocol for the detection of irradiated black pepper. (author)

247

Intrusion detection using pattern recognition methods  

Science.gov (United States)

Today, cyber attacks such as worms, scanning, active attackers are pervasive in Internet. A number of security approaches are proposed to address this problem, among which the intrusion detection system (IDS) appears to be one of the major and most effective solutions for defending against malicious users. Essentially, intrusion detection problem can be generalized as a classification problem, whose goal is to distinguish normal behaviors and anomalies. There are many well-known pattern recognition algorithms for classification purpose. In this paper we describe the details of applying pattern recognition methods to the intrusion detection research field. Experimenting on the KDDCUP 99 data set, we first use information gain metric to reduce the dimensionality of the original feature space. Two supervised methods, the support vector machine as well as the multi-layer neural network have been tested and the results display high detection rate and low false alarm rate, which is promising for real world applications. In addition, three unsupervised methods, Single-Linkage, K-Means, and CLIQUE, are also implemented and evaluated in the paper. The low computational complexity reveals their application in initial data reduction process.

Jiang, Nan; Yu, Li

2007-09-01

248

Noise Radiation Measure-Sound Power and its Test Methods  

OpenAIRE

This study mainly aims to study the characteristics and theory of sound radiation of steady-state vibration. Study shows that sound radiation power of steady-state vibration is constant. And taking excavator for experimental object by hemisphere surface method, the radiated sound power of the excavator is the same as testing the sound pressure on various surfaces based on relevant international standard. Finally, a test method of radiated sound power for cylindrical vibration object is proposed.

Zeng Xianren; Zuo Yanyan

2013-01-01

249

Numerical methods in multidimensional radiative transfer  

CERN Document Server

Offers an overview of the numerical modelling of radiation fields in multidimensional geometries. This book covers advances and problems in the mathematical treatment of the radiative transfer equation, a partial integro-differential equation of high dimension that describes the propagation of the radiation in various fields.

Meinköhn, Erik

2008-01-01

250

Identification of oxidation states of ultra-trace elements by radiation detection  

International Nuclear Information System (INIS)

The determination of the oxidation state of ultra-trace elements in the environment, especially in the case of actinides, is of importance in many ways. Speciation techniques using radiation may comprise methods based on the detection of the nuclear and atomic radiations emitted in radioactive decay or methods using external sources of excitation. In the former instance, information can be obtained from the energy and intensity of radiation, but at present the partition method is still the most commonly used, although its reliability is questionable. Excitation with intense laser beams, as is currently being used for trace element analysis in photoacoustic and thermal lensing spectroscopic techniques, could conceivably be applied under suitable conditions to ultra-trace elements with a sensitivity approaching that of the radiochemical methods

251

A novel method for detection of apoptosis  

International Nuclear Information System (INIS)

There are two different Angiotensin II (ANG II) peptides in nature: Human type (ANG II) and Bovine type (ANG II*). These eight amino acid peptides differ only at position 5 where Valine is replaced by Isoleucine in the Bovine type. They are present in all species studied so far. These amino acids are different by only one atom of carbon. This difference is so small, that it will allow any of ANG II, Bovine or Human antibodies to interact with all species and create a universal method for apoptosis detection. ANG II concentrations are found at substantially higher levels in apoptotic, compared to non-apoptotic, tissues. ANG II accumulation can lead to DNA damage, mutations, carcinogenesis and cell death. We demonstrate that Bovine antiserum can be used for universal detection of apoptosis. In 2010, the worldwide market for apoptosis detection reached the $20 billion mark and significantly increases each year. Most commercially available methods are related to Annexin V and TUNNEL. Our new method based on ANG II is more widely known to physicians and scientists compared to previously used methods. Our approach offers a novel alternative for assessing apoptosis activity with enhanced sensitivity, at a lower cost and ease of use.

252

A method for characterizing photon radiation fields  

Energy Technology Data Exchange (ETDEWEB)

Uncertainty in dosimetric and exposure rate measurements can increase in areas where multi-directional and low-energy photons (< 100 keV) exist because of variations in energy and angular measurement response. Also, accurate measurement of external exposures in spatially non-uniform fields may require multiple dosimetry. Therefore, knowledge of the photon fields in the workplace is required for full understanding of the accuracy of dosimeters and instruments, and for determining the need for multiple dosimeters. This project was designed to develop methods to characterize photon radiation fields in the workplace, and to test the methods in a plutonium facility. The photon field at selected work locations was characterized using TLDs and a collimated NaI(Tl) detector from which spatial variations in photon energy distributions were calculated from measured spectra. Laboratory results showed the accuracy and utility of the method. Field measurement results combined with observed work patterns suggested the following: (1) workers are exposed from all directions, but not isotropically, (2) photon energy distributions were directionally dependent, (3) stuffing nearby gloves into the glovebox reduced exposure rates significantly, (4) dosimeter placement on the front of the chest provided for a reasonable estimate of the average dose equivalent to workers` torsos, (5) justifiable conclusions regarding the need for multiple dosimetry can be made using this quantitative method, and (6) measurements of the exposure rates with ionization chambers pointed with open beta windows toward the glovebox provided the highest measured rates, although absolute accuracy of the field measurements still needs to be assessed.

Whicker, J.J.; Hsu, H.H. [Los Alamos National Lab., NM (United States); Hsieh, F.H.; Borak, T.B. [Colorado State Univ., Fort Collins, CO (United States). Dept. of Radiological Health Sciences

1999-04-01

253

Development of detection methods for irradiated foods  

International Nuclear Information System (INIS)

To identify irradiated foods, studies have been carried out with electron spin resonance (ESR) spectroscopy on bone containing foods, such as chicken, pork, and beef. The intensity of the signal induced in bones increased linearly with irradiation doses in the range of 1.0 kGy to 5.0 kGy, and it was possible to distinguish between samples given low and high doses of irradiation. The signal stability for 6 weeks made them ideal for the quick and easy identification of irradiated meats. The analysis of DNA damage made on single cells by agarose gel electrophoresis (DNA 'comet assay') can be used to detect irradiated food. All the samples irradiated with over 0.3 kGy were identified to detect post-irradiation by the tail length of their comets. Irradiated samples showed comets with long tails, and the tail length of the comets increased with the dose, while unirradiated samples showed no or very short tails. As a result of the above experiment, the DNA 'comet assay' might be applied to the detection of irradiated grains as a simple, low-cost and rapid screening test. When fats are irradiated, hydrocarbons contained one or two fewer carbon atoms are formed from the parent fatty acids. The major hydrocarbons in irradiated beef, pork and chicken were 1,7-hexadecadiene and 8-heptadecene originating from leic acid. 1,7 hexadecadiene was the highest amount in irradiated beef, pork and chicken. Eight kinds of hydrocarbons were identified from irradiated chicken, among which 1,7-hexadecadiene and 8-heptadecen were detected as major compounds. The concentration of radiation-induced hydrocarbons was relatively constant during 16 weeks

254

Surface shape recognition method for crack detection  

Science.gov (United States)

Computer vision-based crack detection methods for large-scale civil structures are mainly developed within the framework of image enhancement and segmentation. In contrast, we propose an idea that converts the images into parametric surfaces and then detects the crack surfaces using shape recognition techniques. The shape variations among noncrack surfaces are caused by approximately isometric deformations, but the dissimilarities between crack and noncrack surfaces are produced by nonisometric deformations. Therefore, the two classes of surfaces can be discriminated by their geodesic distance maps. To tackle the disturbances caused by the gaps in cracks, we develop a dedicated method, steady marching method, for the computation of the distance maps. In the subsequent quantitative comparison, we first construct distance difference matrices from the distance maps. Next, sub-block contrast ratios of these matrices are calculated and used as shape descriptors, which can be directly compared for the surface classification. Experimental results demonstrate that our method achieves a better performance than some typical methods. The extension of our method for crack localization is also presented.

Zhao, Guoteng; Wang, Tongqing; Ye, Junyong

2014-05-01

255

Position sensitive detection of neutrons in high radiation background field  

Science.gov (United States)

We present the development of a high-resolution position sensitive device for detection of slow neutrons in the environment of extremely high ? and e- radiation background. We make use of a planar silicon pixelated (pixel size: 55 × 55 ?m2) spectroscopic Timepix detector adapted for neutron detection utilizing very thin 10B converter placed onto detector surface. We demonstrate that electromagnetic radiation background can be discriminated from the neutron signal utilizing the fact that each particle type produces characteristic ionization tracks in the pixelated detector. Particular tracks can be distinguished by their 2D shape (in the detector plane) and spectroscopic response using single event analysis. A Cd sheet served as thermal neutron stopper as well as intensive source of gamma rays and energetic electrons. Highly efficient discrimination was successful even at very low neutron to electromagnetic background ratio about 10-4.

Vavrik, D.; Jakubek, J.; Pospisil, S.; Vacik, J.

2014-01-01

256

Position sensitive detection of neutrons in high radiation background field  

Energy Technology Data Exchange (ETDEWEB)

We present the development of a high-resolution position sensitive device for detection of slow neutrons in the environment of extremely high ? and e{sup ?} radiation background. We make use of a planar silicon pixelated (pixel size: 55 × 55 ?m{sup 2}) spectroscopic Timepix detector adapted for neutron detection utilizing very thin {sup 10}B converter placed onto detector surface. We demonstrate that electromagnetic radiation background can be discriminated from the neutron signal utilizing the fact that each particle type produces characteristic ionization tracks in the pixelated detector. Particular tracks can be distinguished by their 2D shape (in the detector plane) and spectroscopic response using single event analysis. A Cd sheet served as thermal neutron stopper as well as intensive source of gamma rays and energetic electrons. Highly efficient discrimination was successful even at very low neutron to electromagnetic background ratio about 10{sup ?4}.

Vavrik, D., E-mail: vavrik@itam.cas.cz [Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska 3a/22, Prague (Czech Republic); Institute of Theoretical and Applied Mechanics, Academy of Sciences of the Czech Republic, Prosecka 76, 190 00 Prague 9 (Czech Republic); Jakubek, J.; Pospisil, S. [Institute of Theoretical and Applied Mechanics, Academy of Sciences of the Czech Republic, Prosecka 76, 190 00 Prague 9 (Czech Republic); Vacik, J. [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Rez, 250 68 Prague, Czech Republic (Czech Republic)

2014-01-15

257

Small Teleoperated Robot for Nuclear Radiation and Chemical Leak Detection  

Directory of Open Access Journals (Sweden)

Full Text Available In order to meet the actual requirements of nuclear radiation and chemical leak detection, and emergency response, a new small teleoperated robot for nuclear radiation and chemical detection is proposed. A small?size robot is manufactured according to technical requirements and the overall structure and control system is described. Meanwhile, based on the principles of human?robot interaction, a user?friendly human?robot interaction interface is designed to provide a good telepresence for the operator, helping the operator to perceive and judge the robot’s situation to better assist in making the right decisions and in giving timely operation instructions. The experiment results show the robot system operates reliably and meets the technical requirements.

Kui Qian

2012-09-01

258

Research and Design of Rootkit Detection Method  

Science.gov (United States)

Rootkit is one of the most important issues of network communication systems, which is related to the security and privacy of Internet users. Because of the existence of the back door of the operating system, a hacker can use rootkit to attack and invade other people's computers and thus he can capture passwords and message traffic to and from these computers easily. With the development of the rootkit technology, its applications are more and more extensive and it becomes increasingly difficult to detect it. In addition, for various reasons such as trade secrets, being difficult to be developed, and so on, the rootkit detection technology information and effective tools are still relatively scarce. In this paper, based on the in-depth analysis of the rootkit detection technology, a new kind of the rootkit detection structure is designed and a new method (software), X-Anti, is proposed. Test results show that software designed based on structure proposed is much more efficient than any other rootkit detection software.

Liu, Leian; Yin, Zuanxing; Shen, Yuli; Lin, Haitao; Wang, Hongjiang

259

Detecting data anomalies methods in distributed systems  

Science.gov (United States)

Distributed systems became most popular systems in big companies. Nowadays many telecommunications companies want to hold large volumes of data about all customers. Obviously, those data cannot be stored in single database because of many technical difficulties, such as data access efficiency, security reasons, etc. On the other hand there is no need to hold all data in one place, because companies already have dedicated systems to perform specific tasks. In the distributed systems there is a redundancy of data and each system holds only interesting data in appropriate form. Data updated in one system should be also updated in the rest of systems, which hold that data. There are technical problems to update those data in all systems in transactional way. This article is about data anomalies in distributed systems. Avail data anomalies detection methods are shown. Furthermore, a new initial concept of new data anomalies detection methods is described on the last section.

Mosiej, Lukasz

2009-06-01

260

Development of a distributed radiation detection system using optical fibers  

Energy Technology Data Exchange (ETDEWEB)

We have confirmed the importance of temperature and dose rate for the response of Ge-doped fibers to radiation. A phenomenological model have been found to account for temperature and dose rate effects. From this model it is possible to make dose predictions from attenuation measurements when the temperature and dose rate are known. Ge-doped fibers have been found to have a relatively low sensitivity to both neutron and gamma radiation. In addition, temperature and dose rate dependencies complicate the analysis. However we point out that these problems may all be solved if we use fibers, such as P-doped fibers, which contain color centers of long lifetime. This would remove both the temperature and dose rate dependencies that complicate the use of Ge-doped fibers, in addition the radiation sensitivity is increased. Finally OTDR has been investigated as a possible read-out method for distributed radiation measurements. For our system the minimum pulse length was 3ns, giving a spatial resolution in the meter range and a response length to radiation of about 10 m if accurate dose values where to be obtained. We found OTDR to be a suitable method for radiation induced attenuation measurements in optical fibers, especially for long fiber lengths and long time scales where questions of light source stability becomes important for other systems. (S.Y.)

Jensen, F.; Inouchi, Goro; Takada, Eiji; Takahashi, Hiroyuki; Iguchi, Tetsuo; Nakazawa, Masaharu [Tokyo Univ. (Japan). Faculty of Engineering; Kakuta, Tsunemi

1996-07-01

261

Application of single-chip microcomputer in radiation detection  

International Nuclear Information System (INIS)

The single-chip microcomputer has some advantages in many aspects for example the strong function, the small volume, the low-power, firmed and reliable. It is used widely in the control of industry, instrument, communication and machine, etc.. The paper introduces that the single-chip microcomputer is used in radiation detection, mostly including the use of control, linear, compensation, calculation, prefabricated change, improving precision and training

262

Designing metal-organic frameworks for radiation detection  

International Nuclear Information System (INIS)

Five metal-organic frameworks (MOFs) were synthesized and investigated via steady-state photoluminescence and radioluminescence measurements. Unique spectral features were observed in the 2.5 MeV proton spectra, corresponding to differences in the electronic and crystalline structures of each material. Targeted structural transformations and infiltration with extrinsic dopants were also employed to modify the luminescence of these frameworks, establishing MOFs as a platform to design new radiation detection materials.

263

Signal processing methods for landmine detection.  

OpenAIRE

The millions of landmines spread out over the planet are not only a humanitarian disaster, they also hinder the social and economic development of the concerned countries. In this thesis, new signal processing methods are proposed for the detection and localization of landmines on data recorded by a GPR (Ground Penetrating Radar). First, two digital filters are designed in order to remove clutter in Bscan and Cscan data delivered by GPRs. These two kinds of data are respectively interpreted a...

Potin, Delphine

2007-01-01

264

Detection Method of TOXOPLASMA GONDII Tachyzoites  

Science.gov (United States)

Tachyzoites are considered to be the most important stage of Toxoplasma gondii which causes toxoplasmosis. T. gondii is, an obligate intracellular parasite which infects a wide range of cells. The present study was designed to develop a method for an early detection of T. gondii tachyzoites. The method comprised of a binding assay which was analyzed using principal component and cluster analysis. Our data showed that glycoconjugates GC1, GC2, GC3 and GC10 exhibit a significantly higher binding affinity for T. gondii tachyzoites as compared to controls (T. gondii only, PAA only, GC 1, 2, 3, and 10 only).

Eassa, Souzan; Bose, Chhanda; Alusta, Pierre; Tarasenko, Olga

2011-06-01

265

A new IQ detection method for LLRF  

Energy Technology Data Exchange (ETDEWEB)

Digital LLRF technology has been widely used in new generation particle accelerators. IF quadrature sampling is a common method for amplitude and phase detection. Many strategies, which obey the same rule of f{sub sample}=(M/N)f{sub IF} (M/N is a rational number), have been proposed to reduce the effects of spectrum aliasing. However, we found that M/N does not need to be a rational number according to Shannon's theorem. Therefore, we propose a new IQ detection method in this paper. This method is based on a special IIR filter which is derived from an RLC circuit. The unique characteristic of the method is that the value of f{sub IF} is independent of the value of f{sub sample}. We have set up an experimental platform to verify our method. A 122.88 MHz sampling clock is used to sample a 3 MHz IF signal. The DDS and PI control techniques are used to realize the closed-loop control. Results show that the stability of the system is within {+-} 0.05% (peak to peak) for the amplitude, and with {+-}0.03 Degree-Sign (peak to peak) for the phase in 5 h.

Qiu, Feng, E-mail: qiuf@ihep.ac.cn [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Gao, Jie; Lin, Hai-ying; Liu, Rong [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Ma, Xin-peng [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Sha, Peng; Sun, Yi; Wang, Guang-wei; Wang, Qun-yao; Xu, Bo [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Zeng, Ri-hua [European Spallation Source ESS ABP.O Box 176, SE-221 00 Lund (Sweden)

2012-05-21

266

A new IQ detection method for LLRF  

International Nuclear Information System (INIS)

Digital LLRF technology has been widely used in new generation particle accelerators. IF quadrature sampling is a common method for amplitude and phase detection. Many strategies, which obey the same rule of fsample=(M/N)fIF (M/N is a rational number), have been proposed to reduce the effects of spectrum aliasing. However, we found that M/N does not need to be a rational number according to Shannon's theorem. Therefore, we propose a new IQ detection method in this paper. This method is based on a special IIR filter which is derived from an RLC circuit. The unique characteristic of the method is that the value of fIF is independent of the value of fsample. We have set up an experimental platform to verify our method. A 122.88 MHz sampling clock is used to sample a 3 MHz IF signal. The DDS and PI control techniques are used to realize the closed-loop control. Results show that the stability of the system is within ± 0.05% (peak to peak) for the amplitude, and with ±0.03° (peak to peak) for the phase in 5 h.

267

Physical bases of testing materials and products by induced radiation method (neutron-gamma type)  

International Nuclear Information System (INIS)

A possibility of applying detection of capture ?-radiation under neutron irradiation of an object (laminated and composite articles) for solving problems of nondestructive testing is considered. Realization of the neutron-gamma testing method is based on neutron irradiation of the investigated object and simultaneous detection with spectrometric detectors of ?-radiation of thermal neutrons capture by the corresponding elements. The effect of neutron reflector (moderator) sizes on spatial distribution of the rmal neutron flux density in the object tested are graphically presented. The results of investigation into detection of a defect at different depths of deposition at different position relatively to the measuring unit are described. It is revealed that the quasialbedo nethod based on detection of secondary capture ?-radiation in the 7-9 MeV energy range of detection ensures identification of the defect at depths up to 70 mm

268

Doppler method leak detection for LMFBR steam generators. Pt. 3. Investigation of detection sensitivity and method  

International Nuclear Information System (INIS)

To prevent the expansion of tube damage and to maintain structural integrity in the steam generators (SGs) of a fast breeder reactor (FBR), it is necessary to detect precisely and immediately any leakage of water from heat transfer tubes. Therefore, the Doppler method was developed. Previous studies have revealed that, in the SG full-sector model that simulates actual SGs, the Doppler method can detect bubbles of 0.4 l/s within a few seconds. However in consideration of the dissolution rate of hydrogen generated by a sodium-water reaction even from a small water leak, it is necessary to detect smaller leakages of water from the heat transfer tubes. The detection sensitivity of the Doppler method and the influence of background noise were experimentally investigated. In-water experiments were performed using the SG model. The results show that the Doppler method can detect bubbles of 0.01 l/s (equivalent to a water leak rate of about 0.01 g/s) within a few seconds and that the background noise has little effect on water leak detection performance. The Doppler method thus has great potential for the detection of water leakage in SGs. (author)

269

Detection and spectral measurements of coherent synchrotron radiation at FLASH  

Energy Technology Data Exchange (ETDEWEB)

The operation of high-gain free-electron laser (FEL) underlies tremendous demands on high quality electron beams with high peak currents. At the Free-Electron-Laser in Hamburg (FLASH), two magnetic bunch compressors are used to compress the electron bunches longitudinally. In the bunch compressor magnets, these short electron bunches generate coherent synchrotron radiation (CSR). This CSR contains information on the longitudinal bunch profile, which is relevant for driving an FEL. In order to investigate coherent synchrotron radiation at the second bunch compressor BC3 at FLASH, a new setup behind the last dipole was installed. For the detection of coherent synchrotron radiation, which is emitted in the infrared regime, pyroelectric detectors were used. These pyroelectric detectors have been calibrated at the free-electron laser FELIX in the wavelength range from 5 {mu}m to 110 {mu}m. For characterisation of the emitted radiation, a transverse scanning device was used to measure the transverse intensity distribution. Various transmission filters were used to obtain additional information about the spectral content. In order to get spectral information with high resolution over a wide wavelength range, a rotating mirror spectrometer using reflective blazed gratings was installed. Using this spectrometer, the first spectral measurements of coherent synchrotron radiation at FLASH in a wavelength range from 10 {mu}m to 160 {mu}m were done. (orig.)

Behrens, Christopher

2010-02-15

270

A fast, simple method for screening radiation susceptibility genes by RNA interference  

International Nuclear Information System (INIS)

Radiotherapy can cause unacceptable levels of damage to normal tissues in some cancer patients. To understand the molecular mechanisms underlying radiation-induced physiological responses, and to be able to predict the radiation susceptibility of normal tissues in individual patients, it is important to identify a comprehensive set of genes responsible for radiation susceptibility. We have developed a simple and rapid 96-well screening protocol using cell proliferation assays and RNA interference to identify genes associated with radiation susceptibility. We evaluated the performance of alamarBlue-, BrdU-, and sulforhodamine B-based cell proliferation assays using the 96-well format. Each proliferation assay detected the known radiation susceptibility gene, PRKDC. In a trial screen using 28 shRNA vectors, another known gene, CDKN1A, and one new radiation susceptibility gene, ATP5G3, were identified. Our results indicate that this method may be useful for large-scale screens designed to identify novel radiation susceptibility genes

271

Method for the diffraction of terrestrial radiation, GAMMA radiation, etc  

International Nuclear Information System (INIS)

The patent claim concerns shielding against so-called earth radiation. These rays originate from water veins etc., cannot be defined any closer, and are supposed to cause injury to health. The author claims that shielding is possible with the aid of welding electrodes which have cores of nickel. (ORU/LN)

272

Practical methods for radiation survey in nuclear installations  

International Nuclear Information System (INIS)

This study is placed to those who are responsible to perform radiation survey in the nuclear installations, especially the beginners. Therefore, it gives a comprehensive view to all-important aspects related to their work starting from the structure of atoms to the practical steps for radiation survey works. So, it clarify how to perform personal monitoring, methods for monitoring surface contamination, methods for measuring radioactivity of gases and radioactive aerosols in air, monitoring radiation doses, measuring radiation influences in workplaces and finally measuring internal exposure of radiation workers in nuclear installations. Finally, The study shows some cases of breaches of radiation protection rules in some American nuclear installations and describes the final results of these breaches. The aim of this is to assure that any breach or ignore to radiation protection principles may produce bad results, and there is no leniency in implementing environmental radiation protection principles. (author)

273

Novel Methods of Hydrogen Leak Detection  

International Nuclear Information System (INIS)

With the advent of the fuel cell technology and a drive for clean fuel, hydrogen gas is emerging as a leading candidate for the fuel of choice. For hydrogen to become a consumer fuel for automotive and domestic power generation, safety is paramount. It is, therefore, desired to have a method and system for hydrogen leak detection using odorant which can incorporate a uniform concentration of odorant in the hydrogen gas, when odorants are mixed in the hydrogen storage or delivery means. It is also desired to develop methods where the odorant is not added to the bulk hydrogen, keeping it free of the odorization additives. When odorants are not added to the hydrogen gas in the storage or delivery means, methods must be developed to incorporate odorant in the leaking gas so that leaks can be detected by small. Further, when odorants are not added to the stored hydrogen, it may also be desirable to observe leaks by sight by discoloration of the surface of the storage or transportation vessels. A series of novel solutions are proposed which address the issues raised above. These solutions are divided into three categories as follows: 1. Methods incorporating an odorant in the path of hydrogen leak as opposed to adding it to the hydrogen gas. 2. Methods where odorants are generated in-situ by chemical reaction with the leaking hydrogen 3. Methods of dispensing and storing odorants in high pressure hydrogen gas which release odorants to the gas at a uniform and predetermined to the gas at a uniform and predetermined rates. Use of one or more of the methods described here in conjunction with appropriate engineering solutions will assure the ultimate safety of hydrogen use as a commercial fuel. (authors)

274

Radiation detection and situation management by distributed sensor networks  

Energy Technology Data Exchange (ETDEWEB)

Detection of radioactive materials in an urban environment usually requires large, portal-monitor-style radiation detectors. However, this may not be a practical solution in many transport scenarios. Alternatively, a distributed sensor network (DSN) could complement portal-style detection of radiological materials through the implementation of arrays of low cost, small heterogeneous sensors with the ability to detect the presence of radioactive materials in a moving vehicle over a specific region. In this paper, we report on the use of a heterogeneous, wireless, distributed sensor network for traffic monitoring in a field demonstration. Through wireless communications, the energy spectra from different radiation detectors are combined to improve the detection confidence. In addition, the DSN exploits other sensor technologies and algorithms to provide additional information about the vehicle, such as its speed, location, class (e.g. car, truck), and license plate number. The sensors are in-situ and data is processed in real-time at each node. Relevant information from each node is sent to a base station computer which is used to assess the movement of radioactive materials.

Jan, Frigo [Los Alamos National Laboratory; Mielke, Angela [Los Alamos National Laboratory; Cai, D Michael [Los Alamos National Laboratory

2009-01-01

275

Radiation detection and situation management by distributed sensor networks  

International Nuclear Information System (INIS)

Detection of radioactive materials in an urban environment usually requires large, portal-monitor-style radiation detectors. However, this may not be a practical solution in many transport scenarios. Alternatively, a distributed sensor network (DSN) could complement portal-style detection of radiological materials through the implementation of arrays of low cost, small heterogeneous sensors with the ability to detect the presence of radioactive materials in a moving vehicle over a specific region. In this paper, we report on the use of a heterogeneous, wireless, distributed sensor network for traffic monitoring in a field demonstration. Through wireless communications, the energy spectra from different radiation detectors are combined to improve the detection confidence. In addition, the DSN exploits other sensor technologies and algorithms to provide additional information about the vehicle, such as its speed, location, class (e.g. car, truck), and license plate number. The sensors are in-situ and data is processed in real-time at each node. Relevant information from each node is sent to a base station computer which is used to assess the movement of radioactive materials

276

A Parallel Tracking Method for Acoustic Radiation Force Impulse Imaging  

OpenAIRE

Radiation force-based techniques have been developed by several groups for imaging the mechanical properties of tissue. Acoustic Radiation Force Impulse (ARFI) imaging is one such method that uses commercially available scanners to generate localized radiation forces in tissue. The response of the tissue to the radiation force is determined using conventional B-mode imaging pulses to track micron-scale displacements in tissue. Current research in ARFI imaging is focused on producing real-time...

Dahl, Jeremy J.; Pinton, Gianmarco F.; Mark, L.; Agrawal, Vineet; Nightingale, Kathryn R.; Trahey, Gregg E.

2007-01-01

277

Sea water leak detection method and device  

International Nuclear Information System (INIS)

In a method of detecting sea water leakage by detecting it based on electroconductivity or electric resistance of condensates taken out of a condensator of a power plant, the condensates are degassed to remove gaseous carbon dioxide dissolved in the condensate, before the detection for the electroconductivity of the condensates. Alternatively, a degassing means for removing gaseous carbon dioxide dissolved in the condensate is disposed to a prestage of the condensate electroconductivity measuring means. The degassing means comprises a membrane-degassing device, and the membrane-degassing device comprises a hollow thread membrane for passing through the condensate and permeating gaseous carbon dioxide in the condensates and an evacuating device to form a pressure reduced space on the side opposite to the water passing side of the hollow thread membrane, and allows the dissolved gaseous carbon dioxide in the condensates to permeate on the side of the pressure reduced space by way of the hollow thread membrane. Erroneous operation of the condensator due to vacuum breakage is prevented thereby capable of reliably detecting the leakage of sea water, and the power plant can be restarted rapidly with no time loss. (N.H.)

278

Compact endocavity diagnostic probes for nuclear radiation detection  

Energy Technology Data Exchange (ETDEWEB)

This invention relates to the field of radiation imaging. In particular, the invention relates to an apparatus and a method for imaging tissue or an inanimate object using a novel probe that has an integrated solid-state semiconductor detector and complete readout electronics circuitry.

Cui, Yonggang; James, Ralph; Bolotnikov, Aleksey

2014-08-26

279

Developments in Nanosecond Pulse Detection Methods and Technology  

CERN Document Server

A promising method for the detection of UHE neutrinos is the Lunar Cherenkov technique, which utilises Earth-based radio telescopes to detect the coherent Cherenkov radiation emitted when a UHE neutrino interacts in the outer layers of the Moon. The LUNASKA project aims to overcome the technological limitations of past experiments to utilise the next generation of radio telescopes in the search for these elusive particles. To take advantage of broad-bandwidth data from potentially thousands of antennas requires advances in signal processing technology. Here we describe recent developments in this field and their application in the search for UHE neutrinos, from a preliminary experiment using the first stage of an upgrade to the Australia Telescope Compact Array, to possibilities for fully utilising the completed Square Kilometre Array. We also explore a new real time technique for characterising ionospheric pulse dispersion which specifically measures ionospheric electron content that is line of sight to the ...

McFadden, R A; Ekers, R D; James, C W; Jones, D; Tingay, S J; Roberts, P P; Phillips, C J; Protheroe, R J

2008-01-01

280

Influence of ionising radiation on macromolecular components of wheat; possible use in detecting irradiated wheat  

Energy Technology Data Exchange (ETDEWEB)

The treatment of food by ionising radiation is already permitted by many governments and is under consideration by many others. Cereal are irradiated as a means of disinfestation, this study investigates the effects of such processing on the components of wheat and examines using such radiation induced changes to detect irradiation. Wheat has been irradiated with ionising radiation in the dose range up to 1 kGy. The rheological properties of doughs prepared from this irradiated wheat have been investigated. An immunological assay has been employed to investigate the effect of wheat irradiation on the integrity of gliadin. A method has been developed for the routine isolation of DNA from wheat. Radiation-induced disruption of the DNA double helix has been assessed in DNA extracted from irradiated wheat and calf thymus DNA irradiated in aqueous solution. (author).

Jabir, A.-W.Sh.

1992-01-01

281

Influence of ionising radiation on macromolecular components of wheat; possible use in detecting irradiated wheat  

International Nuclear Information System (INIS)

The treatment of food by ionising radiation is already permitted by many governments and is under consideration by many others. Cereal are irradiated as a means of disinfestation, this study investigates the effects of such processing on the components of wheat and examines using such radiation induced changes to detect irradiation. Wheat has been irradiated with ionising radiation in the dose range up to 1 kGy. The rheological properties of doughs prepared from this irradiated wheat have been investigated. An immunological assay has been employed to investigate the effect of wheat irradiation on the integrity of gliadin. A method has been developed for the routine isolation of DNA from wheat. Radiation-induced disruption of the DNA double helix has been assessed in DNA extracted from irradiated wheat and calf thymus DNA irradiated in aqueous solution. (author)

282

Failed fuel detection method and detection device therefor  

International Nuclear Information System (INIS)

The present invention provide a method and a device for detecting a failed fuel, in which the detection sensitivity of delayed neutrons released from fission products leaked from a defective fuel assembly in a FBR type reactor is improved. That is, a fist neutron detector is disposed at a position near an intermediate heat exchanger of the FBR type reactor, where the level of prompt neutrons emitted from a reactor core is low. A second neutron detector is disposed at a place except for the vicinity of the intermediate heat exchanger, where the level of prompt neutrons emitted from the reactor core is also low. A calculation processing section is disposed for outputting a calculated difference signals calculated based on the output signals from the first neutron detector and the output signal from the second neutron detector. With such a constitution, signal components of the failed fuel can be determined at a good sensitivity efficiency based on the calculation difference between both of the signals from the first neutron detector which outputs addition signals for each of components of the failed fuel and the back ground of the reactor and from the second neutron detector which outputs background component signals of the reactor core. (I.S.)

283

New Method for Detecting Cellular Transforming Genes  

Science.gov (United States)

Tumor induction in athymic nude mice can be used to detect dominant transforming genes in cellular DNA. Mouse NIH 3T3 cells freshly transfected with either cloned Moloney sarcoma proviral DNA or cellular DNA's derived from virally transformed cells induced tumors when injected into athymic nu/nu mice. Tumors were also induced by cells transfected with DNA from two tumor-derived and one chemically transformed human cell lines. The mouse tumors induced by human cell line DNA's contained human DNA sequences, and DNA derived from these tumors was capable of inducing both tumors and foci on subsequent transfection. Tumor induction in nude mice represents a useful new method for the detection and selection of cells transformed by cellular oncogenes.

Blair, D. G.; Cooper, C. S.; Oskarsson, M. K.; Eader, L. A.; Vande Woude, G. F.

1982-12-01

284

Detection of hemorrhagic hypointense foci in radiation injury region using susceptibility-weighted imaging  

International Nuclear Information System (INIS)

Background: Susceptibility-weighted imaging (SWI), a novel, highly sensitive 3D gradient echo MR imaging technique, is used to detect hemorrhage. Purpose: To evaluate SWI at 3.0T for detection and visualization of hemorrhage at radiation injury region after radiotherapy for brain glioma. Material and Methods: In 16 patients who had radiation injury in the vicinity of the previously resected and irradiated high-grade brain glioma, SWI examinations were performed on a 3T MR scanner. The presence of intralesional hypointense foci on SWI was evaluated by two neuroradiologists. Frequency of these foci on SWI was assessed and the number of these foci was counted. Diagnosis of radiation injury was assigned by means of histopathology or follow-up MR image. Results: In all 16 cases with cerebral radiation injury, nine were verified by means of histopathologic examination, seven by follow-up image. While in one patient quality of SWI was poor, in all remaining patients diagnostic-quality SWI was obtained. The intralesional hypointense foci were detected in 12 of 15 patients. These hypointense foci were nodular, angular, or tubular regions of low signal intensity on SWI. The distribution of these foci was diffusive (n = 5) or scattered (n = 7). Number of these foci per cm2 on SWI was 7.25 ± 3.67. Conclusion: SWI is a novel and promising technique for evaluation of hemorrhage at radiation injury regions in the vicinity of the previously treated gliomasreated gliomas

285

A novel mobile system for radiation detection and monitoring  

Science.gov (United States)

A novel mobile system for real time, wide area radiation surveillance has been developed within the REWARD project, financed within the FP7 programme, theme SEC-2011.1.5-1 (Development of detection capabilities of difficult to detect radioactive sources and nuclear materials - Capability Project). The REWARD sensing units are small, mobile portable units with low energy consumption, which consist of new miniaturized solid-state radiation sensors: a CdZnTe detector for gamma radiation and a high efficiency neutron detector based on novel silicon technologies. The sensing unit is integrated by a wireless communication interface to send the data remotely to a monitoring base station as well as a GPS system to calculate the position of the tag. The system also incorporates middleware and high-level software to provide web-service interfaces for the exchange of information. A central monitoring and decision support system has been designed to process the data from the sensing units and to compare them with historical record in order to generate an alarm when an abnormal situation is detected. A security framework ensures protection against unauthorized access to the network and data, ensuring the privacy of the communications and contributing to the overall robustness and reliability of the REWARD system. The REWARD system has been designed for many different scenarios such as nuclear terrorism threats, lost radioactive sources, radioactive contamination or nuclear accidents. It can be deployed in emergency units and in general in any type of mobile or static equipment, but also inside public/private buildings or infrastructures. The complete system is scalable in terms of complexity and cost and offers very high precision on both the measurement and the location of the radiation. The modularity and flexibility of the system allows for a realistic introduction to the market. Authorities may start with a basic, low cost system and increase the complexity based on their evolving needs and budget constraints. On 24th September 2013, REWARD project received a prize as the best Innovative project related to the Not Conventional Threat (NCT) Chemical Biological Radiological Nuclear explosives (CBRNe) products. A highly distinguished jury stated that "the developed detection and surveillance system offers a perfect solution for end-users to enhance crucial capabilities in RN analysis, risk communication and surveillance in case of a radiation incident". A demonstration of the REWARD system is planned in Naples on September 2014. More information about the REWARD project can be found at www.reward-project.eu.

Biafore, Mauro

2014-05-01

286

Methods and means of remote detection of oil pollutants of water. II. Active detection methods  

Energy Technology Data Exchange (ETDEWEB)

The authors discuss active methods for detecting oil pollutants of water, and they evaluate the practical use of these methods. Sensing of pollutants by the active method is based on the difference in the reflecting, scattering, or fluorescing properties of clean and oil-covered water. The methods for such active analysis involve radar and laser technology. The authors conclude that, although only the visual and photographic methods are now being used, it is expedient to introduce the radar, fluorescent, and active optical radar methods as the most promising alternatives.

Bogorodskii, V.V.; Kropotkin, M.A.

1985-07-01

287

Development of detection methods for irradiated foods - Development of detection method for radiolytic products of irradiated foods  

Energy Technology Data Exchange (ETDEWEB)

Meats, nuts, legumes and cereals were irradiated with {sup 60}Co {gamma}-ray. The detection methods included the fat extraction from samples, isolation of hydrocarbons and 2-alkylcyclobutanones by florisil column chromatography and analyses of GC-FID and GC/MS analyzers. Concentrations of hydrocarbons and 2-clobutanones increased with the irradiation dose in meat, nuts, legumes and cereals. In nuts (sesame seeds, black sesame seeds, perilla seeds, pine nuts and peanuts), legumes (white beans, black soybeans, yellow bean sprout soybeans, mouse-eyed soybeans, mung beans, kidney beans and small red beans) and cereals (brown rice, corns and wheat), 8-heptadecene and 1,7-hexadecadiene originated from oleic acid and 6,9-heptadecadiene and 1,7,10-hexadecatriene induced from linoleic acids were the major hydrocarbons due to the composition of fatty acids. Concentrations of radiation-induced hydrocarbons in nuts were slightly reduced and hydrocarbons were still significantly detectable, during 6 months at -18 deg. C. In meats and nuts, 2-(5'-tetradecenyl)cyclobutanone formed from oleic acid was found in most. 2-Dodecylcyclobutanone was detected in a large amount. The concentrations of radiation-induced 2-alkylcyclobutanones in meats slightly decreased, but relatively constant during 6 months at -18 deg. C. 62 refs., 45 figs., 25 tabs. (Author)

Kim, Kyong Su; Lee, Eun Ryong; Hong, Hae Jung [Chosun University, Kwangju (Korea)

2000-07-01

288

Detection of neutral particle radiation with the Mars Science Laboratory (MSL) Radiation Assessment Detector (RAD)  

Science.gov (United States)

RAD, the Radiation Assessment Detector on NASA's Mars Science Laboratory (MSL) rover mission is designed to detect a wide range of different particle species at energies up to 100 MeV/nuc. We present the beam testing results for the flight units of the RAD Sensor Head unit (RSH). Neutral particle response, anti-coincidence efficiency as well as behaviour for relativistic high-Z (up to iron) particles will be shown. Additionally, we present the response of our RSH GEANT4 model for the expected (simulated) Mars surface radiation environment.

Kortmann, O.; Martin, C.; Boehm, E.; Boettcher, S.; Wimmer-Schweingruber, R. F.; Burmeister, S.; Ehresmann, B.; Hassler, D. M.; Zeitlin, C.; Posner, A.; Rafkin, S.; Weigle, E.; Neal, K.; Reitz, G.

2008-12-01

289

Detection of neutral particle radiation with the Mars Science Laboratory (MSL) Radiation Assessment Detector (RAD)  

International Nuclear Information System (INIS)

RAD, the Radiation Assessment Detector on NASA's Mars Science Laboratory (MSL) rover mission is designed to detect a wide range of different particle species at energies up to 100 MeV/nuc. We present the beam testing results for the flight units of the RAD Sensor Head unit (RSH). Neutral particle response, anti-coincidence efficiency as well as behaviour for relativistic high-Z (up to iron) particles are shown. Additionally, we present the response of our RSH GEANT4 model for the expected (simulated) Mars surface radiation environment.

290

On the net radiation method for heat transfer  

CERN Document Server

A simplifying approach for calculating the radiant energy is achieved by introducing the concept of net transmittance, resulting in a novel variation of the net radiation method that provides an easy way for solving a variety of situations. In particular, a closed form for the net radiation between two grey plates through a radiation shield formed by a series of partially transparent partially reflecting partially absorbing plates is found. In addition, the method is generalized to cylindrical and spherical geometries.

Micco, C D

2003-01-01

291

Method of preparing radiation shielding materials  

International Nuclear Information System (INIS)

Purpose: To improve the optical transparency and the mechanical strength of radiation shielding materials. Method: A monomer matrix consisting of a monomer (a) selected from one or more of alkyl methacrylate, hydroxy alkylacrylate, hydroxy alkylmethacrylate of 1-4 carbon atoms in alkyl group and styrene and a monomer (b) contained by 8-75 % by weight of the total amount of (a) and (b) and represented by the formula: CH2 = CR1 - CO - (A-O)sub(n) - CO - CR1 = CH2, where R1 represents H or CH3, A represents alkylene of 2-4 carbon atoms and n represents an integer of 2-60 or represented by the formula: (CH2 = CR2 - CO - O)sub(m) - B, where R2 represents H or CH3, B represents a hydrocarbon residue of 4-25 carbon atmos and m represents an integer of 2-4, is polymerized while incorporated with lead acrylate or lead methacylate by X% by weight of the total monomer and an organic acid salt of lead by Y parts by weight based on 100 parts by weight of the total monomer and represented by the formula: (RCOO)sub(a)Pb, where R represent a hydrocarbon residue of 5-20 carbon atoms and a represents an integer equal to the atomic valency of lead, such that X and Y satisfy the following relations: 200 >= Y >= 2 provided that 9 = Y >= 2/5 (X - 30) + 2 provided that 30 <= X <= 75. (Ikeda, J.)

292

Detection of viability: radiopharmacological conditions, methods, indications  

International Nuclear Information System (INIS)

The indication of revascularization in patients with coronary artery disease is mainly based on factors such as coronary anatomy ischemia as well as ventricular function, patient's biological age or accompanying diseases. In general, evidence of vital myocardium plays a secondary role but will be important in patients with hibernating myocardium. Tl-201 scintigraphy with re-injection technique or rest-redistribution-examination is a simple and cost-effective method of the detection or exclusion of hibernation. However, in case of doubt F-18 FDG PET is recommended to guide further therapeutic strategies. (orig.)

293

Apparatus and method for detecting explosives  

International Nuclear Information System (INIS)

An apparatus is described for use in situations such as airports to detect explosives hidden in containers (for eg. suitcases). The method involves the evaluation of the quantities of oxygen and nitrogen within the container by neutron activation analysis and the determination of whether these quantities exceed predetermined limits. The equipment includes a small sub-critical lower powered reactor for thermal (0.01 to 0.10 eV) neutron production, a radium beryllium primary source, a deuterium-tritium reactor as a high energy (> 1.06 MeV) neutron source and Geiger counter detector arrays. (UK)

294

Electromagnetic radiation. Variational methods, waveguides and accelerators  

International Nuclear Information System (INIS)

This is a graduate level textbook on the theory of electromagnetic radiation and its application to waveguides, transmission lines, accelerator physics and synchrotron radiation. It has grown out of lectures and manuscripts by Julian Schwinger prepared during the war at MIT's Radiation Laboratory, updated with material developed by Schwinger at UCLA in the 1970s and 1980s, and by Milton at the University of Oklahoma since 1994. The book includes a great number of straightforward and challenging exercises and problems. It is addressed to students in physics, electrical engineering, and applied mathematics seeking a thorough introduction to electromagnetism with emphasis on radiation theory and its applications. A hardcover edition containing additionally the reprints of more than 15 papers by Schwinger on these topics is available separately. (orig.)

295

Traumatic Brain Injury Detection Using Electrophysiological Methods  

Science.gov (United States)

Measuring neuronal activity with electrophysiological methods may be useful in detecting neurological dysfunctions, such as mild traumatic brain injury (mTBI). This approach may be particularly valuable for rapid detection in at-risk populations including military service members and athletes. Electrophysiological methods, such as quantitative electroencephalography (qEEG) and recording event-related potentials (ERPs) may be promising; however, the field is nascent and significant controversy exists on the efficacy and accuracy of the approaches as diagnostic tools. For example, the specific measures derived from an electroencephalogram (EEG) that are most suitable as markers of dysfunction have not been clearly established. A study was conducted to summarize and evaluate the statistical rigor of evidence on the overall utility of qEEG as an mTBI detection tool. The analysis evaluated qEEG measures/parameters that may be most suitable as fieldable diagnostic tools, identified other types of EEG measures and analysis methods of promise, recommended specific measures and analysis methods for further development as mTBI detection tools, identified research gaps in the field, and recommended future research and development thrust areas. The qEEG study group formed the following conclusions: (1) Individual qEEG measures provide limited diagnostic utility for mTBI. However, many measures can be important features of qEEG discriminant functions, which do show significant promise as mTBI detection tools. (2) ERPs offer utility in mTBI detection. In fact, evidence indicates that ERPs can identify abnormalities in cases where EEGs alone are non-disclosing. (3) The standard mathematical procedures used in the characterization of mTBI EEGs should be expanded to incorporate newer methods of analysis including non-linear dynamical analysis, complexity measures, analysis of causal interactions, graph theory, and information dynamics. (4) Reports of high specificity in qEEG evaluations of TBI must be interpreted with care. High specificities have been reported in carefully constructed clinical studies in which healthy controls were compared against a carefully selected TBI population. The published literature indicates, however, that similar abnormalities in qEEG measures are observed in other neuropsychiatric disorders. While it may be possible to distinguish a clinical patient from a healthy control participant with this technology, these measures are unlikely to discriminate between, for example, major depressive disorder, bipolar disorder, or TBI. The specificities observed in these clinical studies may well be lost in real world clinical practice. (5) The absence of specificity does not preclude clinical utility. The possibility of use as a longitudinal measure of treatment response remains. However, efficacy as a longitudinal clinical measure does require acceptable test–retest reliability. To date, very few test–retest reliability studies have been published with qEEG data obtained from TBI patients or from healthy controls. This is a particular concern because high variability is a known characteristic of the injured central nervous system.

Rapp, Paul E.; Keyser, David O.; Albano, Alfonso; Hernandez, Rene; Gibson, Douglas B.; Zambon, Robert A.; Hairston, W. David; Hughes, John D.; Krystal, Andrew; Nichols, Andrew S.

2015-01-01

296

Studies on radiation detection using long lasting phosphor  

International Nuclear Information System (INIS)

A green long lasting phosphor SrAl2O4:Eu2+, Dy3+ has been investigated for the radiation detection. It is shown that LLP (long lasting phosphor) has sensitivity to various radiations (alpha, beta and gamma ray) and the total phosphorescence intensity responses linearly in certain range of absorbed dose. Neutrons have not been surveyed in this study, but neutrons can be detected by using of LLP in principal if various converters for detection (Gd, polyethylene and so on) are used. The components of phosphorescence are confirmed four components. The delay constant of the fastest component is 0.59 and the slowest component does not appear in the accumulating process and is only observed in the afterglow process. It is confirmed that the phosphorescence efficiency of alpha ray has the great difference from that of beta or gamma ray. This difference is attributed to the difference of local charge density and initial recombination rate of charge pairs produced by the incident particle. (S.Y.)

297

Nonparametric methods for measurements below detection limit.  

Science.gov (United States)

Analytical data are often subject to left-censoring when the actual values to be quantified fall below the limit of detection. The primary interest of this paper is statistical inference for the two-sample problem. Most of the current publications are centered around naive approaches or the parametric Tobit model approach. These methods may not be suitable for data with high censoring rates and relatively small sample sizes. In this paper, we establish the theoretical equivalence of three nonparametric methods: the Wilcoxon rank sum, the Gehan, and the Peto-Peto tests, under fixed left-censoring and other mild conditions. We then develop a nonparametric point and interval estimation procedure for the location shift model. A large set of simulations compares 14 methods including naive, parametric, and nonparametric methods. The results clearly favor the nonparametric methods for a range of sample sizes and censoring rates. Simulations also demonstrate satisfactory point and interval estimation results. Finally, a real data example is given followed by discussion. PMID:19035469

Zhang, Donghui; Fan, Chunpeng; Zhang, Juan; Zhang, Cun-Hui

2009-02-15

298

Leak and Pipe Detection Method and System  

Science.gov (United States)

A method and system for locating leaks of conductive fluids from non-conductive pipes and other structures or for locat- ing non-conductive pipes or structures having conductive fluid contained therein, employ a charge generator to apply a time varying charge to the conductive fluid, and a capaci- tive type detector that can detect the variable charge that is induced in the fluid. The capacitive detector, which prefer- ably includes a handheld housing, employs a large conduc- tive pickup plate that is used to locate the pipe or leak by scanning the plate over the ground and detecting the induced charge that is generated when the plate comes in close proximity to the pipe or leak. If a leak is encountered, the resulting signal will appear over an area larger than expected for a buried pipe, assuming the leak provides an electrically conductive path between the flow and the wet surrounding ground. The detector uses any suitable type of indicator device, such as a pair of headphones that enable an operator to hear the detected signal as a chirping sound, for example.

Youngquist, Robert C. (Inventor)

2003-01-01

299

Methods and Instruments for Fast Neutron Detection  

Energy Technology Data Exchange (ETDEWEB)

Pacific Northwest National Laboratory evaluated the performance of a large-area (~0.7 m2) plastic scintillator time-of-flight (TOF) sensor for direct detection of fast neutrons. This type of sensor is a readily area-scalable technology that provides broad-area geometrical coverage at a reasonably low cost. It can yield intrinsic detection efficiencies that compare favorably with moderator-based detection methods. The timing resolution achievable should permit substantially more precise time windowing of return neutron flux than would otherwise be possible with moderated detectors. The energy-deposition threshold imposed on each scintillator contributing to the event-definition trigger in a TOF system can be set to blind the sensor to direct emission from the neutron generator. The primary technical challenge addressed in the project was to understand the capabilities of a neutron TOF sensor in the limit of large scintillator area and small scintillator separation, a size regime in which the neutral particle’s flight path between the two scintillators is not tightly constrained.

Jordan, David V.; Reeder, Paul L.; Cooper, Matthew W.; McCormick, Kathleen R.; Peurrung, Anthony J.; Warren, Glen A.

2005-05-01

300

A silicon spectrometer for transition radiation detection for space applications  

International Nuclear Information System (INIS)

A novel design of a Transition Radiation Detector, based on Silicon Microstrip Detectors, is presented. Owing to the relatively high ionization energy release in semiconductor material (a few hundred keV), a magnetic field should be used to separate the radiating particle from TR X-ray photons. We have developed a full Monte-Carlo code to study in detail the performance of this detector such as bending power, strip pitch, charge sharing, and detection efficiency. We also present the results obtained with a small prototype exposed to an electron/pion beam at CERN PS. The particle identification capability allows the distinction of hadron from electrons up to 40 GeV/c and the spectrometer rigidity is almost 40 GV

301

A silicon spectrometer for transition radiation detection for space applications  

CERN Document Server

A novel design of a Transition Radiation Detector, based on Silicon Microstrip Detectors, is presented. Owing to the relatively high ionization energy release in semiconductor material (a few hundred kev), a magnetic field should be used to separate the radiating particle from TR X-ray photons. We have developed a full Monte-Carlo code to study in detail the performance of this detector such as bending power, strip pitch, charge sharing, and detection efficiency. We also present the results obtained with a small prototype exposed to an electron/pion beam at CERN PS. The particle identification capability allows the distinction of hadron from electrons up to 40 GeV/c and the spectrometer rigidity is almost 40 GV.

Brigida, M; Fusco, P; Gargano, F; Giglietto, N; Giordano, F; Loparco, F; Mazziotta, M N; Prest, M; Rainó, S; Spinelli, P; Vallazza, E

2003-01-01

302

Apparatus and method for OSL-based, remote radiation monitoring and spectrometry  

Science.gov (United States)

Compact, OSL-based devices for long-term, unattended radiation detection and spectroscopy are provided. In addition, a method for extracting spectroscopic information from these devices is taught. The devices can comprise OSL pixels and at least one radiation filter surrounding at least a portion of the OSL pixels. The filter can modulate an incident radiation flux. The devices can further comprise a light source and a detector, both proximally located to the OSL pixels, as well as a power source and a wireless communication device, each operably connected to the light source and the detector. Power consumption of the device ranges from ultra-low to zero. The OSL pixels can retain data regarding incident radiation events as trapped charges. The data can be extracted wirelessly or manually. The method for extracting spectroscopic data comprises optically stimulating the exposed OSL pixels, detecting a readout luminescence, and reconstructing an incident-energy spectrum from the luminescence.

Smith, Leon Eric (Richland, WA); Miller, Steven D. (Richland, WA); Bowyer, Theodore W. (Oakton, VA)

2008-05-20

303

Method and system for detecting explosives  

Energy Technology Data Exchange (ETDEWEB)

A method of detecting explosives in a vehicle includes providing a first rack on one side of the vehicle, the rack including a neutron generator and a plurality of gamma ray detectors; providing a second rack on another side of the vehicle, the second rack including a neutron generator and a plurality of gamma ray detectors; providing a control system, remote from the first and second racks, coupled to the neutron generators and gamma ray detectors; using the control system, causing the neutron generators to generate neutrons; and performing gamma ray spectroscopy on spectra read by the gamma ray detectors to look for a signature indicative of presence of an explosive. Various apparatus and other methods are also provided.

Reber, Edward L. (Idaho Falls, ID); Jewell, James K. (Idaho Falls, ID); Rohde, Kenneth W. (Idaho Falls, ID); Seabury, Edward H. (Idaho Falls, ID); Blackwood, Larry G. (Idaho Falls, ID); Edwards, Andrew J. (Idaho Falls, ID); Derr, Kurt W. (Idaho Falls, ID)

2009-03-10

304

Volcanic ash detection with infrared limb sounding: MIPAS observations and radiative transfer simulations  

Science.gov (United States)

Small volcanic ash particles have long residence times in the troposphere and the stratosphere so that they have significant impact on the Earth's radiative budget and consequently affect climate. For global long-term observations of volcanic aerosol, infrared limb measurements provide excellent coverage, sensitivity to thin aerosol layers, and altitude information. The optical properties of volcanic ash and ice particles, derived from micro-physical properties, have opposing spectral gradients between 700 and 960 cm-1 for small particle sizes. Radiative transfer simulations that account for single scattering showed that the opposing spectral gradients directly transfer to infrared limb spectra. Indeed, we found the characteristic spectral signature, expected for volcanic ash, in measurements of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) after the eruption of the Chilean volcano Puyehue-Cordón Caulle in June 2011. From these measurements we derived an ash detection threshold function. The empirical ash detection threshold was confirmed in an extensive simulations study covering a wide range of atmospheric conditions, particle sizes and particle concentrations for ice, volcanic ash and sulfate aerosol. From the simulations we derived the upper detectable effective radius of 3.5 ?m and the detectable extinction coefficient range of 5 × 10-3 to 1 × 10-1 km-1. We also showed that this method is only sensitive to volcanic ash particles, but not to volcanic sulfate aerosol. This volcanic ash detection method for infrared limb measurements is a fast and reliable method and provides complementary information to existing satellite aerosol products.

Griessbach, S.; Hoffmann, L.; Spang, R.; Riese, M.

2014-05-01

305

SARA (Spectroscopic Ambient Radiation Detection) Spectroscopic Monitoring Systems for Online Environmental Radiation Monitoring Edition 2008  

International Nuclear Information System (INIS)

In the wake of a nuclear incident, it is essential that you can react promptly and provide a completely reliable assessment of the radiological situation. First and foremost, it is vital that your radiation early warning system can automatically detect any man-made isotopes in the environment and identify any changes in the composition of the ambient radiation. Before appropriate countermeasures can be implemented, it is crucial that authorities have accurate information about the type of contamination and its dispersion. TechniData's spectroscopic online monitoring system will improve your existing monitoring systems, provide important information about the composition of ambient radiation during an incident, and therefore help you to make the right decisions

306

Possible standoff detection of ionizing radiation using high-power THz electromagnetic waves  

Science.gov (United States)

Recently, a new method of remote detection of concealed radioactive materials was proposed. This method is based on focusing high-power short wavelength electromagnetic radiation in a small volume where the wave electric field exceeds the breakdown threshold. In the presence of free electrons caused by ionizing radiation, in this volume an avalanche discharge can then be initiated. When the wavelength is short enough, the probability of having even one free electron in this small volume in the absence of additional sources of ionization is low. Hence, a high breakdown rate will indicate that in the vicinity of this volume there are some materials causing ionization of air. To prove this concept a 0.67 THz gyrotron delivering 200-300 kW power in 10 microsecond pulses is under development. This method of standoff detection of concealed sources of ionizing radiation requires a wide range of studies, viz., evaluation of possible range, THz power and pulse duration, production of free electrons in air by gamma rays penetrating through container walls, statistical delay time in initiation of the breakdown in the case of low electron density, temporal evolution of plasma structure in the breakdown and scattering of THz radiation from small plasma objects. Most of these issues are discussed in the paper.

Nusinovich, Gregory S.; Sprangle, Phillip; Romero-Talamas, Carlos A.; Rodgers, John; Pu, Ruifeng; Kashyn, Dmytro G.; Antonsen, Thomas M., Jr.; Granatstein, Victor L.

2012-06-01

307

Radiation detection performance of very high gain avalanche photodiodes  

International Nuclear Information System (INIS)

Large area silicon avalanche photodiodes (APDs) have been fabricated with maximum avalanche gains exceeding 10 000 and with relatively flat signal-to-noise performance from gains of a few hundred to gains of a few thousand. Gain and noise performance as well as detector speed of response is presented for APDs with active areas of 4 mm2 and 64 mm2. An overview of the performance of these devices as radiation detectors includes pulse height spectra using the APD as a scintillation spectrometer coupled to CsI(Tl) and to plastic scintillator, and also for direct detection of low energy X-rays. ((orig.))

308

Photocurrent-based detection of terahertz radiation in graphene  

Energy Technology Data Exchange (ETDEWEB)

Graphene is a promising candidate for the development of detectors of Terahertz (THz) radiation. A well-known detection scheme due to Dyakonov and Shur exploits plasma waves in a field-effect transistor (FET), whereby a dc photovoltage is generated in response to a THz field. In the quest for devices with a better signal-to-noise ratio, we theoretically investigate a plasma-wave photodetector in which a dc photocurrent is generated in a graphene FET. The noise equivalent power of our device is shown to be much smaller than that of a Dyakonov-Shur detector in a wide spectral range.

Tomadin, Andrea, E-mail: andrea.tomadin@sns.it; Tredicucci, Alessandro; Vitiello, Miriam S.; Polini, Marco [NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56126 Pisa (Italy); Pellegrini, Vittorio [NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56126 Pisa (Italy); Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy)

2013-11-18

309

Photocurrent-based detection of terahertz radiation in graphene  

International Nuclear Information System (INIS)

Graphene is a promising candidate for the development of detectors of Terahertz (THz) radiation. A well-known detection scheme due to Dyakonov and Shur exploits plasma waves in a field-effect transistor (FET), whereby a dc photovoltage is generated in response to a THz field. In the quest for devices with a better signal-to-noise ratio, we theoretically investigate a plasma-wave photodetector in which a dc photocurrent is generated in a graphene FET. The noise equivalent power of our device is shown to be much smaller than that of a Dyakonov-Shur detector in a wide spectral range

310

Neutrons and gamma radiation propagation: calculation methods and computer codes  

International Nuclear Information System (INIS)

The propagation of neutrons outside the core forms the basis of physical phenomena which are important for the operation of reactors: damage to the vessel in connection with this fluence, neutronic detection, for example. The propagation of neutral particles within the material is rigorously controlled by Boltzmann's equation. This assesses the balance, at any given moment, for a given point and direction, between the neutral particles (neutrons and gamma particles) appearing after fission, disintegration or diffusion from one point to another and those which disappear due to absorption or diffusion. Boltzmann's equation, put into the integro-differential form, is used exclusively in studies of protection. It is then often referred to as 'the transport equation'. Moreover, in protection we are dealing, in most cases with very steep flux gradients (high levels of attenuation) which induce anisotropic flux. It is thus imperative to consider the diffusion of particles in an anisotropic manner, which implies developing the cross sections into Legendre Pn polynomials. In the attempt to resolve this transport equation, there have been important developments concerning three types of method in the field of protection, namely: - numeric methods such as the SN method (discrete ordinates method); - synthetic methods based on more approximate modelling of physical phenomena, such as the straight-line attenuation of radiation; - Monte Carlo methods which, while they are numerics lo methods which, while they are numerics and can be used to solve Boltzmann's equation in virtually all cases, display specific characteristics and are of great importance for protection cases. The aim of this note is to introduce these main methods and the codes which make them up, some of which have been developed in France and some abroad (U.S.A.)

311

Apparatus and method to achieve high-resolution microscopy with non-diffracting or refracting radiation  

Science.gov (United States)

An imaging system employing a coded aperture mask having multiple pinholes is provided. The coded aperture mask is placed at a radiation source to pass the radiation through. The radiation impinges on, and passes through an object, which alters the radiation by absorption and/or scattering. Upon passing through the object, the radiation is detected at a detector plane to form an encoded image, which includes information on the absorption and/or scattering caused by the material and structural attributes of the object. The encoded image is decoded to provide a reconstructed image of the object. Because the coded aperture mask includes multiple pinholes, the radiation intensity is greater than a comparable system employing a single pinhole, thereby enabling a higher resolution. Further, the decoding of the encoded image can be performed to generate multiple images of the object at different distances from the detector plane. Methods and programs for operating the imaging system are also disclosed.

Tobin, Jr., Kenneth W.; Bingham, Philip R.; Hawari, Ayman I.

2012-11-06

312

Ticor-based scintillation detectors for detection of mixed radiation  

CERN Document Server

Detection of mixed radiation of thermal neutrons and gamma-rays have been realized using a new ceramic material based on small-crystalline long-wave scintillator alpha-Al sub 2 O sub 3 :Ti (Ticor) and lithium fluoride. Characteristics are presented for scintillators with Si-PIN-PD type photoreceivers and PMT under sup 2 sup 3 sup 9 Pu alpha-particles, sup 2 sup 0 sup 7 Bi internal conversion electrons,as well as sup 2 sup 4 sup 1 Am and sup 1 sup 3 sup 7 Cs gamma-quanta. Detection efficiency of thermal neutron is estimated for composite materials based on Ticor and lithium fluoride.

Litvinov, L A; Kolner, V B; Ryzhikov, V D; Volkov, V G; Tarasov, V A; Zelenskaya, O V

2002-01-01

313

Thermoluminescence method for detection of irradiated food  

Energy Technology Data Exchange (ETDEWEB)

A method of thermoluminescence (TL) analysis was developed for the detection of irradiated foods. The TL method is based on the determination of thermoluminescence of adhering or contaminating minerals separated from foods by wet sieving and treatment with high density liquid. Carbon tetrachloride provided a suitable alternative for foods that form gels with water. Thermoluminescence response of minerals in a first TL measurement is normalised with a second TL measurement of the same mineral sample after calibration irradiation to a dose of 5 kGy. The decision about irradiation is made on the basis of a comparison of the two TL spectra: if the two TL glow curves match in shape and intensity the sample has been irradiated, and if they are clearly different it has not been irradiated. An attractive feature of TL analysis is that the mineral material itself is used for calibration; no reference material is required. Foods of interest in the investigation were herbs, spices, berries and seafood. The presence of minerals in samples is a criterion for application of the method, and appropriate minerals were found in all herbs, spices and berries. The most common minerals in terrestrial food were tecto-silicates - quartz and feldspars - which with their intense and stable thermoluminescence were well suited for the analysis. Mica proved to be useless for detection purposes, whereas carbonate in the form of calcite separated from intestines of seafood was acceptable. Fading of the TL signal is considerable in the low temperature part of the glow curve during a storage of several months after irradiation. However, spices and herbs could easily be identified as irradiated even after two years storage. Conditions for seafood, which is stored in a freezer, are different, and only slight fading was observed after one year. The effect of mineral composition and structure on TL was studied for feldspars. Feldspars originating from subtropical and tropical regions exhibit lower TL intensity than feldspars from cold regions, evidently because a more altered mineral structure is typical in warm water regions. A new autoradiographic method to determine luminescence of irradiated rock surfaces was developed for the study. The method of thermoluminescence analysis has been used for the official control analysis of irradiated food in Finland since 1990. In the course of the study, about 500 analyses were carried out for the Finnish Customs Laboratory. Eighty lots of irradiated herbs or spices and 10 lots of irradiated seafood were found. During the last two years, irradiated green tea in spice mixtures and irradiated frog legs have been detected. No irradiated berry or mushroom products have been found. Screening with a photostimulated luminescence (PSL) instrument, followed by TL analysis to confirm the positive and ambiguous samples, provides a reliable tool for the identification of irradiated food containing adhering or contaminating minerals. The reliability of the TL method was proved in European trials. Standardisation of the method has been undertaken by the European Committee for Standardization (CEN). A TL method based on the determination of TL silicate minerals in dry herbs and spices has recently been accepted as an official CEN standard. (orig.) 55 refs.

Pinnioja, S

1998-12-31

314

[A hyperspectral small target detection method based on outlier detection].  

Science.gov (United States)

In the present paper, a new method was discussed, which used outlier detection algorithms of spectral analytical technology to tell the small target from background. First, continuum removal and standard normal variate were employed to pretreat the AVIRIS remotely-sensed data. It could be regarded that continuum is the absorption of background, and the characteristic absorptions are superposed on the continuum. So the continuum removal is frequently applied to remotely-sensed hyperspectral data to eliminate the contribution of background absorption and separate the characteristic absorption of concerned objects from background. SNV corrects each spectrum by subtracting the mean and dividing by the standard deviation for that spectrum. After the pretreatment, spectral angle mapping was used to reduce the dimension of hyperspectral data. Since this mapping process calculated the similarity between the spectra of each pixel and the average spectrum, no prior information such as standard spectrum library is required. And then, Mahalanobis distances were calculated. As Mahalanobis distance shows the extent to which samples deviate from the total population, the points whose Mahalanobis distance are larger than adaptive threshold were regarded as small target. The adaptive threshold was determined by data mean value and maximum value. Applying the algorithm above to a set of AVIRIS remotely-sensed hyperspectral data which was free downloaded from the NASA official website, small target on the concerned area was picked out correctly. In addition, the above mentioned took about 1/8 time as much as the traditional Mahalanobis distance method without prior reducing dimension of hyperspectral data. Compared with traditional algorithm, no prior information is needed, and less calculating work and time is required. Still, it has got a satisfying accuracy. PMID:18975814

Li, Qing-bo; Li, Xiang; Zhang, Guang-jun

2008-08-01

315

Detection of tumor response to radiation therapy by in vivo proton MR spectroscopy  

International Nuclear Information System (INIS)

Purpose: These studies were performed to investigate the effects of radiation on levels of metabolites such as lactate and choline compounds detected by 1H magnetic resonance spectroscopy (MRS). The purpose was to determine the ability of spatially localized 1H MRS to detect tumor response to radiation therapy. Methods and Materials: Proton spectroscopic images were obtained from RIF-1 tumors with voxel spatial resolutions of 8-16 mm3 before and at 24 and 48 h following 2, 4, and 20 Gy of ?-radiation. Results: Lactate levels decreased significantly for all doses by 48 h. Tumors irradiated with 2 and 4 Gy showed a significant decrease by 48 h, but not at 24 h. A group of sham-irradiated control animals demonstrated no significant changes in lactate over the period of observation. Conclusions: Changes in lactate observed in this study are consistent with an increased blood flow observed in previous studies in the same tumor model following 20 Gy X-irradiation. These studies point to the feasibility of detecting response to clinical doses of fractionated radiation therapy by 1H MRS

316

Odour Detection Methods: Olfactometry and Chemical Sensors  

Directory of Open Access Journals (Sweden)

Full Text Available The complexity of the odours issue arises from the sensory nature of smell. From the evolutionary point of view olfaction is one of the oldest senses, allowing for seeking food, recognizing danger or communication: human olfaction is a protective sense as it allows the detection of potential illnesses or infections by taking into account the odour pleasantness/unpleasantness. Odours are mixtures of light and small molecules that, coming in contact with various human sensory systems, also at very low concentrations in the inhaled air, are able to stimulate an anatomical response: the experienced perception is the odour. Odour assessment is a key point in some industrial production processes (i.e., food, beverages, etc. and it is acquiring steady importance in unusual technological fields (i.e., indoor air quality; this issue mainly concerns the environmental impact of various industrial activities (i.e., tanneries, refineries, slaughterhouses, distilleries, civil and industrial wastewater treatment plants, landfills and composting plants as sources of olfactory nuisances, the top air pollution complaint. Although the human olfactory system is still regarded as the most important and effective “analytical instrument” for odour evaluation, the demand for more objective analytical methods, along with the discovery of materials with chemo-electronic properties, has boosted the development of sensor-based machine olfaction potentially imitating the biological system. This review examines the state of the art of both human and instrumental sensing currently used for the detection of odours. The olfactometric techniques employing a panel of trained experts are discussed and the strong and weak points of odour assessment through human detection are highlighted. The main features and the working principles of modern electronic noses (E-Noses are then described, focusing on their better performances for environmental analysis. Odour emission monitoring carried out through both the techniques is finally reviewed in order to show the complementary responses of human and instrumental sensing.

Sara Lovascio

2011-05-01

317

Odour Detection Methods: Olfactometry and Chemical Sensors  

Science.gov (United States)

The complexity of the odours issue arises from the sensory nature of smell. From the evolutionary point of view olfaction is one of the oldest senses, allowing for seeking food, recognizing danger or communication: human olfaction is a protective sense as it allows the detection of potential illnesses or infections by taking into account the odour pleasantness/unpleasantness. Odours are mixtures of light and small molecules that, coming in contact with various human sensory systems, also at very low concentrations in the inhaled air, are able to stimulate an anatomical response: the experienced perception is the odour. Odour assessment is a key point in some industrial production processes (i.e., food, beverages, etc.) and it is acquiring steady importance in unusual technological fields (i.e., indoor air quality); this issue mainly concerns the environmental impact of various industrial activities (i.e., tanneries, refineries, slaughterhouses, distilleries, civil and industrial wastewater treatment plants, landfills and composting plants) as sources of olfactory nuisances, the top air pollution complaint. Although the human olfactory system is still regarded as the most important and effective “analytical instrument” for odour evaluation, the demand for more objective analytical methods, along with the discovery of materials with chemo-electronic properties, has boosted the development of sensor-based machine olfaction potentially imitating the biological system. This review examines the state of the art of both human and instrumental sensing currently used for the detection of odours. The olfactometric techniques employing a panel of trained experts are discussed and the strong and weak points of odour assessment through human detection are highlighted. The main features and the working principles of modern electronic noses (E-Noses) are then described, focusing on their better performances for environmental analysis. Odour emission monitoring carried out through both the techniques is finally reviewed in order to show the complementary responses of human and instrumental sensing. PMID:22163901

Brattoli, Magda; de Gennaro, Gianluigi; de Pinto, Valentina; Loiotile, Annamaria Demarinis; Lovascio, Sara; Penza, Michele

2011-01-01

318

Shielding and Build-up Considerations for Radiation Detection  

International Nuclear Information System (INIS)

Shielding for gamma radiation has traditionally focused on the reduction of dose effects. For these applications, reducing the energy of the radiation is important along with reducing the actual number of photons, and therefore large masses of high Z material are typically used. However, for measurements requiring low backgrounds or for detecting low activity signals, such as in homeland security applications, the primary use of shielding is to decrease the total number of background photons (perhaps in a region of interest), and therefore the processes of buildup and down scattering become important. In these applications, where the important measure is count rate instead of dose and low background are important, improved reduction in counts from background radiation may be achieved with specially designed configurations of thin layers of different materials instead of a single thick layer. This paper briefly describes recent modeling and experimental investigations in layered-shielding methodology and provides results with comparison to single shielding material such as Pb. Application of these techniques to some real world problems, such as detector systems for homeland security, is discussed.

319

Imaginary-time method for radiative capture reaction rate  

OpenAIRE

We propose a new computational method for astrophysical reaction rate of radiative capture process. In the method, an evolution of a wave function is calculated along the imaginary-time axis which is identified as the inverse temperature. It enables direct evaluation of reaction rate as a function of temperature without solving any scattering problem. The method is tested for two-body radiative capture reaction, ${^{16}{\\rm O}}(\\alpha,\\gamma){^{20}{\\rm Ne}}$, showing that it...

Yabana, Kazuhiro; Funaki, Yasuro

2012-01-01

320

Detection methods at reactor neutrino experiments  

Energy Technology Data Exchange (ETDEWEB)

In 2011 and 2012, the smallest neutrino mixing angle ?{sub 13} was determined to be unexpected large by reactor neutrino experiments Daya Bay, Double Chooz, and RENO, and accelerator experiments T2K and MINOS. The most precise measurement is sin{sup 2}2?{sub 13}=0.089±0.010(stat.)±0.005(syst.), provided by Daya Bay. The measurement of ?{sub 13} opened the gateway to the mass hierarchy and CP phase measurements. It also marked the beginning of precision measurements in neutrino studies. With near-far relative measurement and improvements in detector design, the relative precision of neutrino detectors reached 0.2%. Detection methods for reactor neutrinos are reviewed. The highlighted techniques include gadolinium-doped liquid scintillator, three-layer detectors, functionally identical detectors, reflective panel, background shielding, etc. The next generation reactor neutrino experiment Daya Bay II and its technical challenges are briefly described.

Cao, Jun, E-mail: caoj@ihep.ac.cn

2013-12-21

321

Human Portable Radiation Detection System Communications Package Evaluation  

International Nuclear Information System (INIS)

Testing and valuation of the Human Portable Radiation Detection System Communications Package for the US Coast Guard. The main components of the HCP field kit are an Archer Field PC(regsign) and an Iridium satellite phone, along with various charging components and cables. The Archer Field PC has an Enfora Global System for Mobile/General Packet Radio System (GSM/GPRS) wireless cellular modem installed via the compact flash (CF) port. The Iridium satellite phone has a serial communication interface attached. The Archer Field PC is running Windows Mobile(regsign) 5.0 operating system. Included Microsoft products are Excel(regsign) Mobile, PowerPoint(regsign) Mobile, Word(regsign) Mobile, and Internet Explorer(regsign) Mobile. There is an Outlook(regsign) Email program that can be accessed via sending a file or the Messaging link. The Cambridge Computer Corporation vxHpc program is installed to provide a Hyperterm-like software product. vxHpc supports multiple communication protocols. An AT and T SIM card was provided for the GSM wireless cellular modem. A check with AT and T determined the SIM card was not activated to provide cellular service. The Iridium satellite phone did not have a SIM card and has no service. The Archer Field PC boots into a HCP program, displaying the Main Menu. The following actions can be executed by selecting the appropriate box: Spectrum Download, Spectrum Transfer,box: Spectrum Download, Spectrum Transfer, and Admin Control. The Spectrum Download function uses the serial communication port to download data files from another device, such as a Radiation Isotope Identification Device (RIID). The Spectrum Transfer function uses either the installed wireless cellular modem or the Iridium satellite phone (attached to the serial communication port) to send data files to a computer modem at the Laboratories and Scientific Services (LSS). The Admin Control function allows entering phone numbers and data file deletion. PNNL recommends that DNDO (and/or CG) contact Sanmina and request a demo of the HCP Email data capability. The demo should include at a minimum three spectra data file attachments (background, known source, and unknown source) that are sent in the email package. The data should be sent using both included wireless cell phone hardware and the Iridium sat phone. The HCP has been optimized to operate on the Iridium Satellite Network, so that constraint needs to be factored into the selection of a service provider. It is also suggested that discussions with Sanmina work out the best method for CG personnel to use the HCP without requiring a separate email account for each HCP (e.g., similar to a BlackBerry using the member's email account), which should help make the HCP more user friendly.

322

Beta radiation detection with ultra-thin thermoluminescent samples  

International Nuclear Information System (INIS)

The possibility of beta radiation detection using ultra-thin thermoluminescent (TL) Teledyne dosimeters was investigated. The studied samples were UT - CaSO4:Dy with a thickness of 20 microns. The beta irradiations were done utilizing the Beta Secondary Standard System of IPEN calibration laboratory, with 90Sr-90Y, 204Tl and 147Pm sources. The individual reproducibility of the samples was initially investigated. Fifteen TL detectors were used and ten irradiations of 35 m Gy (90Sr-90Y) under identical conditions were performed. The average reproducibility found was 1.51% (1 sigma). Dose calibration curves (TL X absorbed dose) were obtained with 90Sr-90Y, 204Tl and 147Pm sources. The UT - CaSO4:Dy samples were irradiated with the 90Sr-90Y source between 0145 and 300 m Gy; the linear response was observed from 0.50 m Gy. In the case of 204Tl, the TL response was measured from 0.1 to 100 m Gy, with linear behavior from 1 m Gy, while for 147Pm the samples were exposed to radiation between 0.1 and 45 m Gy, presenting linear response from 2 m Gy. The 90Sr-90Y irradiated detectors were exposed to ultraviolet (UV) light (250 nm) to study the possibility of optical fading occurrence. The angular dependence of the TL response was investigated for 90Sr-90Y (20 m Gy), 204Tl (1 m Gy) and 147Pm (1 m Gy) sources at angles of 0, 30, 45, 90, 120, 135, 150 and 1800. Transmission factors for different thicknesses of tissue equivalent materials were obtained for the UT - CaSO4:Dy samples, using the three available beta sources. Finally, the energy dependence of the detector TL response was investigated. The results obtained for UT - CaSO4:Dy show its great usefulness in beta radiation detection

323

Scintillator's sensitivity calibration method in synchrotron radiation facility  

International Nuclear Information System (INIS)

Researches on scintillator's sensitivity method has been carried out recently in Shanghai synchrotron radiation facility. By some experimental researches in light source and detector's linearity, it built a new method for calibrating scintillator's sensitivity. Finally, calibration results were acquired by theory simulation of experimental data which were in accordance with radioactive source methods results, and the new method improved the data accuracy. (authors)

324

Two different hematocrit detection methods: Different methods, different results?  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Less is known about the influence of hematocrit detection methodology on transfusion triggers. Therefore, the aim of the present study was to compare two different hematocrit-assessing methods. In a total of 50 critically ill patients hematocrit was analyzed using (1 blood gas analyzer (ABLflex 800 and (2 the central laboratory method (ADVIA® 2120 and compared. Findings Bland-Altman analysis for repeated measurements showed a good correlation with a bias of +1.39% and 2 SD of ± 3.12%. The 24%-hematocrit-group showed a correlation of r2 = 0.87. With a kappa of 0.56, 22.7% of the cases would have been transfused differently. In the-28%-hematocrit group with a similar correlation (r2 = 0.8 and a kappa of 0.58, 21% of the cases would have been transfused differently. Conclusions Despite a good agreement between the two methods used to determine hematocrit in clinical routine, the calculated difference of 1.4% might substantially influence transfusion triggers depending on the employed method.

Schuepbach Reto A

2010-03-01

325

Recombination methods in the dosimetry of mixed radiation  

International Nuclear Information System (INIS)

The work describes the state of art of recombination methods developed for the dosimetry of mixed radiation fields. The existing theories of initial recombination of ions in gases is given. Recombination methods developed in IAE are reviewed in detail. The methods described here can be applied in mixed radiation fields of poorly known composition and practically unlimited energy range. Main dosimetric parameters such as absorbed dose, photon component to the absorbed dose, radiation quality factor, dose equivalent, ambient dose equivalent and some other quantities can be determined in single instrument. A novel method has been developed for determination of the energy loss distribution in the nanometric region. Experimental tests showed that the method is promising not only for radiation protection but also for radiobiological investigations. (author). 166 refs, 62 figs, 16 tabs

326

Recombination methods in the dosimetry of mixed radiation  

Energy Technology Data Exchange (ETDEWEB)

The work describes the state of art of recombination methods developed for the dosimetry of mixed radiation fields. The existing theories of initial recombination of ions in gases is given. Recombination methods developed in IAE are reviewed in detail. The methods described here can be applied in mixed radiation fields of poorly known composition and practically unlimited energy range. Main dosimetric parameters such as absorbed dose, photon component to the absorbed dose, radiation quality factor, dose equivalent, ambient dose equivalent and some other quantities can be determined in single instrument. A novel method has been developed for determination of the energy loss distribution in the nanometric region. Experimental tests showed that the method is promising not only for radiation protection but also for radiobiological investigations. (author). 166 refs, 62 figs, 16 tabs.

Golnik, N. [Institute of Atomic Energy, Otwock-Swierk (Poland)

1996-12-31

327

The detection of the X ray blow off impulses under the condition of intense nuclear radiation and its anti-radiation electronic studies  

International Nuclear Information System (INIS)

The detecting studies of the blow off impulses produced in the flat targets irradiated by nuclear explosion X ray are discussed. In detections, the detector principle of directly measuring the specific series of time intervals and variable reluctance transducing technique were used. A set of effective methods of anti-radiative interference are adopted in the whole detecting system. In addition, the moving frictions of the target groups are calibrated on the equipment of powder gun. Finally, the comparisons between the detective data and the computed results about the X ray blow off impulses are given. The results indicate that they coincide with each other satisfactorily

328

Synchrotron radiation. Basics, methods and applications  

Energy Technology Data Exchange (ETDEWEB)

Synchrotron radiation is today extensively used for fundamental and applied research in many different fields of science. Its exceptional characteristics in terms of intensity, brilliance, spectral range, time structure and now also coherence pushed many experimental techniques to previously un-reachable limits, enabling the performance of experiments unbelievable only few years ago. The book gives an up-to-date overview of synchrotron radiation research today with a view to the future, starting from its generation and sources, its interaction with matter, illustrating the main experimental technique employed and provides an overview of the main fields of research in which new and innovative results are obtained. The book is addressed to PhD students and young researchers to provide both an introductory and a rather deep knowledge of the field. It will also be helpful to experienced researcher who want to approach the field in a professional way.

Mobilio, Settimio; Meneghini, Carlo [Roma Tre Univ. (Italy). Dept. of Science; Boscherini, Federico (ed.) [Bologna Univ. (Italy). Dept. of Physics and Astronomy

2015-02-01

329

Synchrotron radiation. Basics, methods and applications  

International Nuclear Information System (INIS)

Synchrotron radiation is today extensively used for fundamental and applied research in many different fields of science. Its exceptional characteristics in terms of intensity, brilliance, spectral range, time structure and now also coherence pushed many experimental techniques to previously un-reachable limits, enabling the performance of experiments unbelievable only few years ago. The book gives an up-to-date overview of synchrotron radiation research today with a view to the future, starting from its generation and sources, its interaction with matter, illustrating the main experimental technique employed and provides an overview of the main fields of research in which new and innovative results are obtained. The book is addressed to PhD students and young researchers to provide both an introductory and a rather deep knowledge of the field. It will also be helpful to experienced researcher who want to approach the field in a professional way.

330

A method for calculation of radiation quantities at all points in gamma radiation calibration fields  

International Nuclear Information System (INIS)

Radiation quantity values at all points of a known distance range of gamma radiation calibration fields were calculated using a mathematical method. The method is based on interpolation using Chi-square test on a set of experimental data at optional points of both collimated and un-collimated calibration set-ups by means of a reference instrument. In comparison with Monte Carlo calculations, the values that were calculated by this method differ by <1% for collimated and 2% for un-collimated calibration set-ups. Consequently, the radiation quantities at all points of gamma radiation calibration field set-ups can accurately be formulated and determined by this method. In addition, all points in the radiation fields can be regarded as test points. (authors)

331

A method for calculation of radiation quantities at all points in gamma radiation calibration fields.  

Science.gov (United States)

Radiation quantity values at all points of a known distance range of gamma radiation calibration fields were calculated using a mathematical method. The method is based on interpolation using Chi-square test on a set of experimental data at optional points of both collimated and un-collimated calibration set-ups by means of a reference instrument. In comparison with Monte Carlo calculations, the values that were calculated by this method differ by <1% for collimated and 2% for un-collimated calibration set-ups. Consequently, the radiation quantities at all points of gamma radiation calibration field set-ups can accurately be formulated and determined by this method. In addition, all points in the radiation fields can be regarded as test points. PMID:17951236

Hosseini-Pooya, S M; Khoshnoodi, M; Ansarinejad, A; Torkzadeh, F; Jafarizadeh, M

2008-01-01

332

Method and apparatus for sequentially combining pulsed beams of radiation  

International Nuclear Information System (INIS)

Method and apparatus are presented for combining a sequence of radiation pulses in plural beams to provide a common axis output beam of increased repetition rate. An optical correction system is employed to compensate for dynamic angular motion of the output radiation beam over the duration of each pulse. (Auth.)

333

Radiation shielding phenolic fibers and method of producing same  

International Nuclear Information System (INIS)

A radiation shielding phenolic fiber is described comprising a filamentary phenolic polymer consisting predominantly of a sulfonic acid group-containing cured novolak resin and a metallic atom having a great radiation shielding capacity, the metallic atom being incorporated in the polymer by being chemically bound in the ionic state in the novolak resin. A method for the production of the fiber is discussed

334

Thermal radiation view factor calculation using Monte Carlo method  

International Nuclear Information System (INIS)

It is necessary to obtain the radiation geometric view factor for calculation of radiation heat transfer problems. There are many studies for calculation methods of the view factors. That are area integration method, line integration method, Mitalas and Stephenson's contour integration method, Hottel's cross-string method and Monte Carlo method. The view factors can be calculated by area integration method and Monte Carlo method, when third surface shading exists. The report is comparative study of the calculation accuracy and computer time between area integration method and Monte Carlo method for view factors. It has been considered that Monte Carlo method is time consuming. However it is clarified from the results that a small amount of emission leads to reasonable view factors and small amount of computer time. Moreover using Monte Carlo method, view factors of multi-body system could be easily obtained through only one computing execution. (author)

335

Sensor And Method For Detecting A Superstrate  

Science.gov (United States)

Method and apparatus are provided for determining a superstrate on or near a sensor, e.g., for detecting the presence of an ice superstrate on an airplane wing or a road. In one preferred embodiment, multiple measurement cells are disposed along a transmission line. While the present invention is operable with different types of transmission lines, construction details for a presently preferred coplanar waveguide and a microstrip waveguide are disclosed. A computer simulation is provided as part of the invention for predicting results of a simulated superstrate detector system. The measurement cells may be physically partitioned, nonphysically partitioned with software or firmware, or include a combination of different types of partitions. In one embodiment, a plurality of transmission lines are utilized wherein each transmission line includes a plurality of measurement cells. The plurality of transmission lines may be multiplexed with the signal from each transmission line being applied to the same phase detector. In one embodiment, an inverse problem method is applied to determine the superstrate dielectric for a transmission line with multiple measurement cells.

Arndt, G. Dickey (Inventor); Cari, James R. (Inventor); Ngo, Phong H. (Inventor); Fink, Patrick W. (Inventor); Siekierski, James D. (Inventor)

2006-01-01

336

Comparative studies of modern methods for caries detection and quantification  

OpenAIRE

In clinical dentistry proper treatment of caries lesions is highly dependent on diagnostic accuracy. Aim The present dissertation aimed at the evaluation and comparisons between several modem methods for caries detection and quantification. Methods The employed methods for detection and quantification of caries lesions may be divided into two categories, namely laser fluorescence based methods and radiographic methods. Laser fluorescence The performance of the...

Shi, Xie-qi

2001-01-01

337

Radiation portal monitor system and method  

Science.gov (United States)

A portal monitoring system has a cosmic ray charged particle tracker with a plurality of drift cells. The drift cells, which can be for example aluminum drift tubes, can be arranged at least above and below a volume to be scanned to thereby track incoming and outgoing charged particles, such as cosmic ray muons, whilst also detecting gamma rays. The system can selectively detect devices or materials, such as iron, lead, gold and/or tungsten, occupying the volume from multiple scattering of the charged particles passing through the volume and can also detect any radioactive sources occupying the volume from gamma rays emitted therefrom. If necessary, the drift tubes can be sealed to eliminate the need for a gas handling system. The system can be employed to inspect occupied vehicles at border crossings for nuclear threat objects.

Morris, Christopher (Los Alamos, NM); Borozdin, Konstantin N. (Los Alamos, NM); Green, J. Andrew (Los Alamos, NM); Hogan, Gary E. (Los Alamos, NM); Makela, Mark F. (Los Alamos, NM); Priedhorsky, William C. (Los Alamos, NM); Saunders, Alexander (Los Alamos, NM); Schultz, Larry J. (Los Alamos, NM); Sossong, Michael J. (Los Alamos, NM)

2009-12-15

338

Direct detection of Black Holes via electromagnetic radiation  

CERN Document Server

Many black hole (BH) candidates exist, ranging from supermassive ($\\sim10^{6}$--$10^{10}$ M$_{\\odot}$) to stellar masses ($\\sim 1$--$100$ M$_{\\odot}$), all of them identified by indirect processes. Although there are no known candidate BHs with sub-stellar masses, these might have been produced in the primordial Universe. BHs emit radiation composed of photons, gravitons and, later in their lifes, massive particles. We explored the detection of such BHs with present day masses from $10^{-22}$ M$_{\\odot}$ to $10^{-11}$ M$_{\\odot}$. We determined the maximum distances ($d$) at which the current best detectors should be placed in order to identify such isolated BHs. Broadly, we conclude that in the visible and ultraviolet BHs can be directly detected at $d\\lesssim 10^7$ m while in the X-ray band the distances might reach $\\sim10^8$ m (of the order of the Earth-Moon distance) and in the $\\gamma$-ray band BHs might even be detected from as far as $\\sim 0.1$ pc. Since these results give us realistic hopes of direct...

Sobrinho, J L G

2014-01-01

339

Detection method for fission product upon failure of nuclear fuels  

International Nuclear Information System (INIS)

The present invention provides a detection method for fission products discharged upon failure of nuclear fuels in an FBR type reactor. Heretofor, the fissile products discharged upon failure of nuclear fuels have been detected by radiometric analysis. Although the radiometric analysis is a highly sensitive detection method, it also detects radioactivity contained in the material, so that the back ground is increased. Moreover, nuclides not having radioactivity can not be detected. The detection method according to the present invention detects fissile products such as xenon, krypton, cesium or the like discharged upon failure of nuclear fuels of the FBR type reactor by multi-photon intensifying ionization method. If gaseous fission products are detected by the multi-photon intensifying ionization method, they can be detected at ultrahigh sensitivity without undergoing influences of the background radioactivity. (I.S.)

340

Comparative analysis of different methods of radiation diagnosis of choledocholithiasis  

International Nuclear Information System (INIS)

The comparative analysis of different methods of radiation diagnosis of choledocholithiasis, i.e. transabdominal ultrasonography, helical computed tomography, magnetic resonance and endoscopic retrograde cholangiography to optimize the indications for their use, depending on the clinical situation was performed

341

Conrolling of radical-ion pair reactions by microwave radiation: photoconductivity-detected magnetic resonance  

Science.gov (United States)

Photoconductivity-detected magnetic resonance has been performed successfully as a new investigation method for transient radical-ion pairs. The chemical reaction of radical-ion pairs is controlled by microwave radiation. The photoionization system of TMPD (N,N,N',N'-tetramethyl-1,4-phenylenediamine) in alcohol is employed. The data show the broadened linewidth of the radical-ion pair spectrum that may be influenced by the microwave field and/or the dynamic motion of the radicals. This observation method is a powerful way of studying the dynamics of transient radical-ion pairs formed in photochemical and photobiological reactions that involve electron transfer reactions.

Murai, Hisao; Matsuyama, Akihito; Ishida, Tateki; Iwasaki, Yohei; Maeda, Kiminori; Azumi, Tohru

1997-01-01

342

Evaluation method for radiative heat transfer in polydisperse water droplets  

International Nuclear Information System (INIS)

Simplifications of the model for nongray radiative heat transfer analysis in participating media comprised of polydisperse water droplets are presented. Databases of the radiative properties for a water droplet over a wide range of wavelengths and diameters are constructed using rigorous Mie theory. The accuracy of the radiative properties obtained from the database interpolation is validated by comparing them with those obtained from the Mie calculations. The radiative properties of polydisperse water droplets are compared with those of monodisperse water droplets with equivalent mean diameters. Nongray radiative heat transfer in the anisotropic scattering fog layer, including direct and diffuse solar irradiations and infrared sky flux, is analyzed using REM2. The radiative heat fluxes within the fog layer containing polydisperse water droplets are compared with those in the layer containing monodisperse water droplets. Through numerical simulation of the radiative heat transfer, polydisperse water droplets can be approximated by using the Sauter diameter, a technique that can be useful in several research fields, such as engineering and atmospheric science. Although this approximation is valid in the case of pure radiative transfer problems, the Sauter diameter is reconfirmed to be the appropriate diameter for approximating problems in radiative heat transfer, although volume-length mean diameter shows better accordance in some cases. The CPU time for nonrdance in some cases. The CPU time for nongray radiative heat transfer analysis with a fog model is evaluated. It is proved that the CPU time is decreased by using the databases and the approximation method for polydisperse particulate media

343

Differential Transformation Method for Temperature Distribution in a Radiating Fin  

DEFF Research Database (Denmark)

Radiating extended surfaces are widely used to enhance heat transfer between a primary surface and the environment. In this paper, the differential transformation method (DTM) is proposed for solving nonlinear differential equation of temperature distribution in a heat radiating fin. The concept of differential transformation is briefly introduced, and then we employed it to derive solutions of two nonlinear equations. The results obtained by DTM are compared with those derived from the analytical solution to verify the accuracy of the proposed method.

Rahimi, M.; Hosseini, M. J.

2011-01-01

344

A new solvent suppression method via radiation damping effect  

International Nuclear Information System (INIS)

Radiation damping effects induced by the dominated solvent in a solution sample can be applied to suppress the solvent signal. The precession pathway and rate back to equilibrium state between solute and solvent spins are different under radiation damping. In this paper, a series of pulse sequences using radiation damping were designed for the solvent suppression in nuclear magnetic resonance (NMR) spectroscopy. Compared to the WATERGATE method, the solute signals adjacent to the solvent would not be influenced by using the radiation damping method. The one-dimensional (1D) 1H NMR, two-dimensional (2D) gCOSY, and J-resolved experimental results show the practicability of solvent suppression via radiation damping effects in 1D and 2D NMR spectroscopy. (interdisciplinary physics and related areas of science and technology)

345

A new solvent suppression method via radiation damping effect  

Science.gov (United States)

Radiation damping effects induced by the dominated solvent in a solution sample can be applied to suppress the solvent signal. The precession pathway and rate back to equilibrium state between solute and solvent spins are different under radiation damping. In this paper, a series of pulse sequences using radiation damping were designed for the solvent suppression in nuclear magnetic resonance (NMR) spectroscopy. Compared to the WATERGATE method, the solute signals adjacent to the solvent would not be influenced by using the radiation damping method. The one-dimensional (1D) 1H NMR, two-dimensional (2D) gCOSY, and J-resolved experimental results show the practicability of solvent suppression via radiation damping effects in 1D and 2D NMR spectroscopy.

Cui, Xiao-Hong; Peng, Ling; Zhang, Zhen-Min; Cai, Shu-Hui; Chen, Zhong

2011-11-01

346

A non-parametric method for correction of global radiation observations  

DEFF Research Database (Denmark)

This paper presents a method for correction and alignment of global radiation observations based on information obtained from calculated global radiation, in the present study one-hour forecast of global radiation from a numerical weather prediction (NWP) model is used. Systematical errors detected in the observations are corrected. These are errors such as: tilt in the leveling of the sensor, shadowing from surrounding objects, clipping and saturation in the signal processing, and errors from dirt and wear. The method is based on a statistical non-parametric clear-sky model which is applied to both the observed and the calculated radiation in order to find systematic deviations between them. The method is applied to correct global radiation observations from a climate station located at a district heating plant in Denmark. The results are compared to observations recorded at the Danish Technical University. The method can be useful for optimized use of solar radiation observations for forecasting, monitoring, and modeling of energy production and load which are affected by solar radiation.

Bacher, Peder; Madsen, Henrik

2013-01-01

347

Radiation detection from phase-locked serial dc SQUID arrays  

DEFF Research Database (Denmark)

We report on synchronous operation of series arrays of inductively coupled superconducting quantum interference devices (SQUIDs). Each array consisted of N=3 or 11 dc SQUIDs with common inductances providing a strong interaction between neighboring cells. Externally shunted (betac[approximately-equal-to]1) trilayer Nb—AlOx—Nb Josephson junctions were used. Coherent radiation was detected in the frequency range f=67–73 GHz while the array voltage was VN=NfPhi0 (Phi0=2.07×10?15 V s). The stability of the coherent state was influenced by the external dc magnetic field. The linewidth depended on the external loading. For small loading it was N times smaller than expected for a single cell. The influence of the inductive coupling mechanism on the operation of discrete Josephson junction circuits and the similarity to the coupling in layered structures of long Josephson junctions is discussed. Journal of Applied Physics is copyrighted by The American Institute of Physics.

Kaplunenko, V. K.; Mygind, Jesper

1993-01-01

348

Detection of orphan radioactive sources during radiation monitoring  

International Nuclear Information System (INIS)

Many radioactive sources are reported as lost every year from different parts of the world due to lack of administrative control or due to theft. Massive search operations carried out led to the discovery of some, few caused radiological emergencies in public domain and many are yet to be traced. Prevention of these orphan sources from causing inadvertent exposure of public can be achieved by timely search and detection operation for these sources. Systems and methodologies for search of orphan sources are developed as a part of BARC Emergency Response Centre's activities and are tested in many aerial and field radiation monitoring exercises. In this paper, results of an estimation carried out to assist the search and locating of orphan sources is presented. Dose rates have been compared at various monitoring locations of three inadequately shielded sources (137Cs, 60Co, 192Ir) of strength 3.7 TBq (100 Ci) each left inside a room of 30cm thick concrete wall. (author)

349

Development of medical application methods using radiation. Radionuclide therapy  

Energy Technology Data Exchange (ETDEWEB)

In this project, we studied following subjects: 1. development of monoclonal antibodies and radiopharmaceuticals 2. clinical applications of radionuclide therapy 3. radioimmunoguided surgery 4. prevention of restenosis with intracoronary radiation. The results can be applied for the following objectives: (1) radionuclide therapy will be applied in clinical practice to treat the cancer patients or other diseases in multi-center trial. (2) The newly developed monoclonal antibodies and biomolecules can be used in biology, chemistry or other basic life science research. (3) The new methods for the analysis of therapeutic effects, such as dosimetry, and quantitative analysis methods of radioactivity, can be applied in basic research, such as radiation oncology and radiation biology.

Choi, Chang Woon; Lim, S. M.; Kim, E.H.; Woo, K. S.; Chung, W. S.; Lim, S. J.; Choi, T. H.; Hong, S. W.; Chung, H. Y.; No, W. C. [Korea Atomic Energy Research Institute. Korea Cancer Center Hospital, Seoul, (Korea, Republic of); Oh, B. H. [Seoul National University. Hospital, Seoul (Korea, Republic of); Hong, H. J. [Antibody Engineering Research Unit, Taejon (Korea, Republic of)

1999-04-01

350

UTILIZATION OF PHOSWICH DETECTORS FOR SIMULTANEOUS, MULTIPLE RADIATION DETECTION  

International Nuclear Information System (INIS)

A phoswich radiation detector is comprised of a phosphor sandwich in which several different phosphors are viewed by a common photomultiplier. By selecting the appropriate phosphors, this system can be used to simultaneously measure multiple radiation types (alpha, beta, gamma and/or neutron) with a single detector. Differentiation between the signals from the different phosphors is accomplished using digital pulse shape discrimination techniques. This method has been shown to result in accurate discrimination with highly reliable and versatile digital systems. This system also requires minimal component count (i.e. only the detector and a computer for signal processing). A variety of detectors of this type have been built and tested including: (1) a triple phoswich system for alpha/beta/gamma swipe counting, (2) two well-type detectors for measuring low levels of low energy photons in the presence of a high energy background, (3) a large area detector for measuring beta contamination in the presence of a photon background, (4) another large area detector for measuring low energy photons from radioactive elements such as uranium in the presence of a photon background. An annular geometry, triple phoswich system optimized for measuring alpha/beta/gamma radiation in liquid waste processing streams is currently being designed

351

The photochemical method for radiation abatement  

International Nuclear Information System (INIS)

This report reviews the underlying chemistry of the photochemical method for removal of radioiodines from air and evaluates the concept with respect to various applications in the nuclear industry. The method uses ultraviolet light (200-300 nm) to convert organic iodides (RI) to elemental iodine (I2). The I2 is then reacted with ozone to form solid iodine oxides (I4O9 or (I2O5), which deposit inside a scrubber. It is concluded that the method is applicable to large-scale systems and would have several advantages over conventional methods of radioiodine abatement

352

In-Situ Radiation Detection Demonstration Final Report  

Energy Technology Data Exchange (ETDEWEB)

The Department of Defense (DoD) has hundreds of facilities where radioactive materials have been used or are being used, including firing ranges, low-level radioactive waste disposal areas, and areas where past activities have resulted in environmental contamination. Affected sites range in size from a few acres to square miles. Impact to the DoD comes through military base closure and release to the public. It is important that radioactive contaminants are remediated to levels that result in acceptable risk to the public. Remediation requires characterization studies, e.g., sampling and surveys, to define the affected areas, removal actions, and final confirmatory sampling and surveys. Characterization of surface contamination concentrations has historically been performed using extensive soil sampling programs in conjunction with surface radiation surveys conducted with hand-held radiation monitoring equipment. Sampling is required within the suspect affected area and a large buffer area. Surface soil contaminant characterization using soil sampling and hand held monitoring are costly, time consuming, and result in long delays between submission of samples for analysis and obtaining of final results. This project took an existing, proven radiation survey technology that has had limited exposure and improved its capabilities by documenting correlation factors for various detector/radionuclide geometries that commonly occur in field surveys. With this tool, one can perform characterization and final release surveys much more quickly than is currently possible, and have detection limits that are as good as or better than current technology. This paper will discuss the capabilities of a large area plastic scintillation detector used in conjunction with a global positioning system (GPS) to improve site characterization, remediation, and final clearance surveys of the radioactively contaminated site. Survey results can rapidly identify areas that require remediation as well as guide surgical removal of contaminated soil that is above remediation guidelines. Post-remediation surveys can document that final radiological site conditions are within the remedial action limits.

MOHAGHEGHI,AMIR H.; REESE,ROBERT; MILLER,DAVID R.; MILLER,MARK LAVERNE; DUCE,STEPHEN

2000-06-01

353

Fiber-optic radiation sensor for detection of tritium  

International Nuclear Information System (INIS)

The objective of this study is to develop the radiation sensor, which is composed of a scintillator, an optical fiber bundle and a light measuring device to detect the tritium in real-time. In this study, we have fabricated fiber-optic radiation sensors using inorganic scintillators and plastic optical fiber bundles. Each scintillator interacts with electron or beta ray and generates 455-550 nm wavelength of scintillation photons. An optical fiber bundle is usually made of plastic or glass, which is used to guide the light signal from a scintillating probe to light measuring device. For the purpose of selecting the best scintillator with a high efficiency, fiber-optic sensors manufactured using three kinds of inorganic scintillator such as Gd2O2S:Tb, Y3Al5O12:Ce and CsI:Tl, and they are tested with a metal hydride type of tritium source. In addition, the scintillation photons are measured as a function of distance between a fiber-optic sensor and source. Finally, we have measured the amounts of scintillation photon with different activities of tritium source and compared the measured results with those obtained using a surface activity monitor.

354

Fiber-optic radiation sensor for detection of tritium  

Energy Technology Data Exchange (ETDEWEB)

The objective of this study is to develop the radiation sensor, which is composed of a scintillator, an optical fiber bundle and a light measuring device to detect the tritium in real-time. In this study, we have fabricated fiber-optic radiation sensors using inorganic scintillators and plastic optical fiber bundles. Each scintillator interacts with electron or beta ray and generates 455-550 nm wavelength of scintillation photons. An optical fiber bundle is usually made of plastic or glass, which is used to guide the light signal from a scintillating probe to light measuring device. For the purpose of selecting the best scintillator with a high efficiency, fiber-optic sensors manufactured using three kinds of inorganic scintillator such as Gd{sub 2}O{sub 2}S:Tb, Y{sub 3}Al{sub 5}O{sub 12}:Ce and CsI:Tl, and they are tested with a metal hydride type of tritium source. In addition, the scintillation photons are measured as a function of distance between a fiber-optic sensor and source. Finally, we have measured the amounts of scintillation photon with different activities of tritium source and compared the measured results with those obtained using a surface activity monitor.

Jang, K.W.; Cho, D.H.; Yoo, W.J.; Seo, J.K.; Heo, J.Y.; Park, J.-Y. [School of Biomedical Engineering, College of Biomedical and Health Science, Research Institute of Biomedical Engineering, Konkuk University, Chungju 380-701 (Korea, Republic of); Lee, B., E-mail: bslee@kku.ac.kr [School of Biomedical Engineering, College of Biomedical and Health Science, Research Institute of Biomedical Engineering, Konkuk University, Chungju 380-701 (Korea, Republic of)

2011-10-01

355

Fiber-optic radiation sensor for detection of tritium  

Science.gov (United States)

The objective of this study is to develop the radiation sensor, which is composed of a scintillator, an optical fiber bundle and a light measuring device to detect the tritium in real-time. In this study, we have fabricated fiber-optic radiation sensors using inorganic scintillators and plastic optical fiber bundles. Each scintillator interacts with electron or beta ray and generates 455-550 nm wavelength of scintillation photons. An optical fiber bundle is usually made of plastic or glass, which is used to guide the light signal from a scintillating probe to light measuring device. For the purpose of selecting the best scintillator with a high efficiency, fiber-optic sensors manufactured using three kinds of inorganic scintillator such as Gd 2O 2S:Tb, Y 3Al 5O 12:Ce and CsI:Tl, and they are tested with a metal hydride type of tritium source. In addition, the scintillation photons are measured as a function of distance between a fiber-optic sensor and source. Finally, we have measured the amounts of scintillation photon with different activities of tritium source and compared the measured results with those obtained using a surface activity monitor.

Jang, K. W.; Cho, D. H.; Yoo, W. J.; Seo, J. K.; Heo, J. Y.; Park, J.-Y.; Lee, B.

2011-10-01

356

Methods of NO detection in exhaled breath.  

Science.gov (United States)

There is still an unexplored potential for exhaled nitric oxide (NO) in many clinical applications. This study presents an overview of the currently available methods for monitoring NO in exhaled breath and the use of the modelling of NO production and transport in the lung in clinical practice. Three technologies are described, namely chemiluminescence, electrochemical sensing and laser-based detection with their advantages and limitations. Comparisons are made in terms of sensitivity, time response, size, costs and suitability for clinical purposes. The importance of the flow rate for NO sampling is discussed from the perspective of the recent recommendations for standardized procedures for online and offline NO measurement. The measurement of NO at one flow rate, such as 50 ml s(-1), can neither determine the alveolar site/peripheral contribution nor quantify the difference in NO diffusion from the airways walls. The use of NO modelling (linear or non-linear approach) can solve this problem and provide useful information about the source of NO. This is of great value in diagnostic procedures of respiratory diseases and in treatment with anti-inflammatory drugs. PMID:23445766

Cristescu, S M; Mandon, J; Harren, F J M; Meriläinen, P; Högman, M

2013-03-01

357

Detection of radiation-induced apoptosis using the comet assay  

International Nuclear Information System (INIS)

The electrophoresis pattern of apoptotic cells detected by the comet assay has a characteristic small head and spread tail. This image has been referred to as an apoptotic comet, but it has not been previously proven to be apoptotic cells by any direct method. In order to identify this image obtained by the comet assay as corresponding to an apoptotic cell, the frequency of appearance of apoptosis was examined using CHO-K1 and L5178Y cells which were exposed to gamma irradiation. As a method for detecting apoptosis, the terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) assay was used. When the frequency of appearance of apoptotic cells following gamma irradiation was observed over a period of time, there was a significant increase in appearance of apoptosis when using the TUNEL assay. However, there was only a slight increase when using the comet assay. In order to verify the low frequency of appearance of apoptosis when using the comet assay, we attempted to use the TUNEL assay to satin the apoptotic comets detected in the comet assay. The apoptotic comets were TUNEL positive and the normal comets were TUNEL negative. This indicates that the apoptotic comets were formed from DNA fragments with 3'-hydroxy ends that are generated as cells undergo apoptosis. Therefore, it was understood that the characteristic pattern of apoptotic comets detected by the comet assay corresponds to cells undergoing apoptosis. (author)tosis. (author)

358

Spectral radiative property control method based on filling solution  

International Nuclear Information System (INIS)

Controlling thermal radiation by tailoring spectral properties of microstructure is a promising method, can be applied in many industrial systems and have been widely researched recently. Among various property tailoring schemes, geometry design of microstructures is a commonly used method. However, the existing radiation property tailoring is limited by adjustability of processed microstructures. In other words, the spectral radiative properties of microscale structures are not possible to change after the gratings are fabricated. In this paper, we propose a method that adjusts the grating spectral properties by means of injecting filling solution, which could modify the thermal radiation in a fabricated microstructure. Therefore, this method overcomes the limitation mentioned above. Both mercury and water are adopted as the filling solution in this study. Aluminum and silver are selected as the grating materials to investigate the generality and limitation of this control method. The rigorous coupled-wave analysis is used to investigate the spectral radiative properties of these filling solution grating structures. A magnetic polaritons mechanism identification method is proposed based on LC circuit model principle. It is found that this control method could be used by different grating materials. Different filling solutions would enable the high absorption peak to move to longer or shorter wavelength band. The results show that the filling solution grating structures are promising for active control of spectral radiative properties. -- Highlights: • A filling solution grating structure is designed to adjust spectral radiative properties. • The mechanism of radiative property control is studied for engineering utilization. • Different grating materials are studied to find multi-functions for grating

359

Improving the detecting performances of radiation portal monitors using matched filter algorithm  

International Nuclear Information System (INIS)

Full text: Introduction: Radiation Portal Monitors (RPM) are used for monitoring transportation of illicit radioactive materials. The application requires detection of radioactive materials while the vehicle is passes through a portal, thus having limited time for monitoring the passing vehicle. The pattern of the RPM detector readings, caused by measuring a moving source versus the background provides an opportunity to employ an algorithm based on matched filter technique for improving the detecting performances. Method: Matched filter is a process used for detecting a known signal in the presence of additive stochastic noise, and thereby maximizing the detected signal to noise ratio (SNR). For RPM's the matched filter is implemented by correlating a known signal, which is distance dependent, with the RPM readings. Convolving those readings, which combine the signal and the noise, with a time-reversed version of the signal, improves the RPM performances. To validate this concept a detection configuration was established according to measuring time limit and Minimal Detectable Activity (MDA) defined by ANSI 42-35 regulation. A mathematical software simulation was performed, followed by an experiment with a scale down configuration in order to confirm the benefits of the suggested algorithm. The experimental setup contained a NaI(Tl) scintillator based radiation detector, a radioactive source located on a moving toy train and a proximity sensor. Results: The detection proximity sensor. Results: The detection performances obtained by both the simulation and the experiment with and without the matched filter algorithm were compared. The software simulation has shown a major improvement of up to six-fold decrease in miss alarm rate. Similar results where obtained by the experiments. Conclusions: The implementation of the matched filter in RPM detection algorithm improves its performances. The method provides either a) a higher detection reliability level, b) the ability to detect lower activity level, c) the need for fewer detectors to achieve the same MDA obtained without the matched filter. The proposed method is almost costless for implementation and requires minor hardware modifications. A future research will evaluate the advantage of the matched filter in cases of a spread source and a source which is not located at the center of the moving vehicle. (author)

360

Apparatus and method for inhibiting the generation of excessive radiation  

International Nuclear Information System (INIS)

This patent describes an apparatus for generating electron radiation or X-ray radiation. It comprises accelerator means for generating and accelerating electrons to form an electron beam which has a predetermined low intensity level for the generation of the electron radiation or a predetermined high intensity level for the generation of the X-ray radiation; supporting means for supporting a scattering foil and a target and for selectively moving either the foil into the trajectory of the electron beam having the low intensity level for generating the electron radiation upon impingement of the electrons there or on the target into the trajectory of the electron beam having the high intensity level for generating the X-ray radiation upon impingement of the electrons thereon; detecting means operable by the supporting means for sensing the position of the target relative to the trajectory of the electron beam; and inhibiting means coupled to the accelerator means and to the detecting means for preventing the generation of an electron beam having the high intensity level if the foil and not the target is positioned in the trajectory of the electron beam

361

Radio frequency detection assembly and method for detecting radio frequencies  

Science.gov (United States)

A radio frequency detection assembly is described and which includes a radio frequency detector which detects a radio frequency emission produced by a radio frequency emitter from a given location which is remote relative to the radio frequency detector; a location assembly electrically coupled with the radio frequency detector and which is operable to estimate the location of the radio frequency emitter from the radio frequency emission which has been received; and a radio frequency transmitter electrically coupled with the radio frequency detector and the location assembly, and which transmits a radio frequency signal which reports the presence of the radio frequency emitter.

Cown, Steven H. (Rigby, ID); Derr, Kurt Warren (Idaho Falls, ID)

2010-03-16

362

Development of detection methods for irradiated foods  

Energy Technology Data Exchange (ETDEWEB)

In 1999, we have been studied (1) on the detection of irradiated foods by ESR spectroscopy, by thermoluminescence, and by viscometry for physical measurements, (2) on the detection of hydrocarbons and 2-alkylcyclobutanones derived from fatty foods by GC/MS for chemical measurements, (3) on the screening and detection of irradiated foods by Comet assay and immunochemical (ELISA) technique for biological or biochemical measurements.

Yang, Jae Seung; Nam, Hye Seon; Oh, Kyong Nam; Woo, Si Ho; Kim, Kyeung Eun; Yi, Sang Duk; Park, Jun Young; Kim, Kyong Su; Hwang, Keum Taek

2000-04-01

363

Development of detection methods for irradiated foods  

International Nuclear Information System (INIS)

In 1999, we have been studied (1) on the detection of irradiated foods by ESR spectroscopy, by thermoluminescence, and by viscometry for physical measurements, (2) on the detection of hydrocarbons and 2-alkylcyclobutanones derived from fatty foods by GC/MS for chemical measurements, (3) on the screening and detection of irradiated foods by Comet assay and immunochemical (ELISA) technique for biological or biochemical measurements

364

Analysis on Credit Card Fraud Detection Methods  

Directory of Open Access Journals (Sweden)

Full Text Available Due to the theatrical increase of fraud which results in loss of dollars worldwide each year, several modern techniques in detecting fraud are persistently evolved and applied to many business fields. Fraud detection involves monitoring the activities of populations of users in order to estimate, perceive or avoid undesirable behavior. Undesirable behavior is a broad term including delinquency, fraud, intrusion, and account defaulting. This paper presents a survey of current techniques used in credit card fraud detection and telecommunication fraud. The goal of this paper is to provide a comprehensive review of different techniques to detect fraud.

Renu

2014-02-01

365

Biochemical and Radiobiological Factors in the Early Detection of Radiation Injury in Mammals  

International Nuclear Information System (INIS)

In considering the body of radiobiological knowledge upon which the present possibilities for the development of an objective quantitative laboratory procedure for early detection of radiation injury depend, it is evident that there are at least three general categories of radiation effects which are relevant to this objective: (1) Products of the enzymatic-chemical breakdown of macromolecules, and lysis of killed or dying cells from radiosensitive tissues, for example deoxypolynucleotides from lymphoid tissues and bone marrow; (2) Radiation-induced inhibition of synthesis of deoxyribonucleic acid (DNA) and/or other macromolecules, eliciting alterations in tissue and blood concentrations and pool size of metabolic intermediates in the synthesis, for example, deoxycytidine; (3) Radiation-induced alterations, suppression, or cessation of specialized cell function; of particular interest here is the immunological functions of lymphocytes, including those in the circulating blood. For rodents, the exquisite radiosensitivity of bone-marrow-stem cells as well as of lymphocytes has been precisely measured by modern cellular radiobiological techniques: the colony-forming technique of Till and McCulloch, yielding a D0 for bone-marrow cells of about 80 R; and the graft-versus-host reactivity of transplanted lymphocytes yielding a similar D0 value. In our own hands, a modified colony-formation technique for dog bone-marrow cells irradiated in.vitro and in vivo give D0 values of ?100 R. Thus, on the basis of radiation sensitivity and the time-relationships for interphase cell death for lymphocytes, it appears that this cell class is probably the best ''candidate'' source for an early radiation-injury detection system. However,- the important report by Zicha and Buric indicates that extrapolation of biochemical data on radiation dosimetry from rodents to man is not necessarily feasible, at least in the. case of the urinary excretion of deoxycytidine after irradiation, since human liver actively de-aminates deoxycytidine, in contrast to rat liver. Biochemical and immunological tests on peripheral blood lymphocytes removed within hours after radiation exposure may afford a sensitive approach to early detection of radiation injury. Thus, DNA synthesis as measured by the incorporation of tritiated thymidine into .the DNA fraction is drastically inhibited in irradiated rat lymphocytes incubated in vitro, in response to the addition of phytohaemagglutinin. Theoretically, the responses of these easily accessible cells to phytohaemagglutinin and to other selected antigens in vitro should be amenable to quantitation after radiation-dose levels which elicit only minimal lymphopenie effects. Further studies on the molecular basis of these radiation effects on lymphocytes, together with deeper insights into the mechanism by which ionizing radiations initiate the sequence of events leading to the breakdown of DNA and the release of histdnes from nucleoproteins of these cells, are required for the implementation of practical methods for biochemical detection of radiation injury in man. (author)

366

New developments in radiation protection instrumentation via active electronic methods  

International Nuclear Information System (INIS)

New developments in electronics and radiation detectors are improving on real-time data acquisition of radiation exposure and contamination conditions. Recent developments in low power circuit designs, hybrid and integrated circuits, and microcomputers have all contributed to smaller and lighter radiation detection instruments that are, at the same time, more sensitive and provide more information (e.g., radioisotope identification) than previous devices. New developments in radiation detectors, such as cadmium telluride, gas scintillation proportional counters, and imaging counters (both charged particle and photon) promise higher sensitivities and expanded uses over present instruments. These developments are being applied in such areas as health physics, waste management, environmental monitoring, in vivo measurements, and nuclear safeguards

367

Discontinuous Galerkin Methods for Computational Radiation Transport  

OpenAIRE

This Thesis demonstrates advanced new discretisation technologies that improve the accuracy and stability of the discontinuous Galerkin finite element method applied to the Boltzmann Transport Equation, describing the advective transport of neutral particles such as photons and neutrons within a domain. The discontinuous Galerkin method in its standard form is susceptible to oscillation detrimental to the solution. The discretisation schemes presented in this Thesis enhance the...

Merton, Simon Richard

2012-01-01

368

Optical fiber detectors as in-vivo dosimetry method of quality assurance in radiation therapy  

International Nuclear Information System (INIS)

A new in-vivo dosimetry system has been under development for some time using radio luminescent phosphors. These phosphors are activated, metal ion doped glasses (Ex: Cu1± doped quartz fiber), have excellent optical transparency and offer several potential advantages for radiation dosimetry; including: small size, high sensitivity, linearity of dose response insensitivity to electromagnetic interference. The utility of these phosphors as a detection modality has been limited in real-time dosimetry applications due to the production of Cerenkov radiation in the carrier fiber, which produces a contaminant signal proportional to dose rate as well as the size of the radiation field. One possible method for eliminating this signal is using an electronic gating signal from the accelerator to delay data acquisition during the actual beam pulse, when Cerenkov radiation is produced. Due to the intrinsic properties of our particular scintillator, this method offers the best mechanism for eliminating Cerenkov noise, while retaining the ability to detect individual beam pulses. The dosimeter was tested using an external beam radiotherapy machine that provided pulses of 6 MeV x-rays. Gated detection was used to discriminate the signal collected during the radiation pulses, which included contributions from Cerenkov radiation and native fiber fluorescence, from the signal collected between the radiation pulses, which contained only the long-lived phosphorescence from thly the long-lived phosphorescence from the Cu1± doped fused quartz detector. Gated detection of the phosphorescence provided accurate, real-time dose measurements that were linear with absorbed dose, independent of dose rate and that were accurate for all field sizes studied. (author)

369

78 FR 64030 - Monitoring Criteria and Methods To Calculate Occupational Radiation Doses  

Science.gov (United States)

...Methods To Calculate Occupational Radiation Doses AGENCY: Nuclear Regulatory Commission...Methods to Calculate Occupational Radiation Doses.'' This guide describes methods...criteria and calculate occupational radiation doses. DATES: Submit comments...

2013-10-25

370

Results of conservative surgery and radiation for mammographically detected ductal carcinoma in situ (DCIS)  

International Nuclear Information System (INIS)

Purpose: The role of conservative surgery and radiation for mammographically detected ductal carcinoma in situ (DCIS) is controversial. In particular, there is little data for outcome with radiation in a group of patients comparable to those treated with local excision and surveillance (mammographic calcifications ?2.5cm, negative resection margins, negative post biopsy mammogram). This study reports outcome of conservative surgery and radiation for mammographically detected DCIS with an emphasis on results in patients considered candidates for excision alone. Methods and Materials: >From 1983 to 1992, 110 women with mammographically detected DCIS (77% calcifications ± mass) and no prior history of breast cancer underwent needle localization and biopsy with (55%) or without a re excision and radiation. Final margins of resection were negative in 62%, positive 7%, close 11%, and unknown 20%. The median patient age was 56 years. The most common histologic subtype was comedo (54%), followed by cribriform (22%). The median pathologic tumor size was 8 mm (range 2 mm to 5 cm). Forty-seven percent of patients with calcifications only had a negative post biopsy mammogram prior to radiation. Radiation consisted of treatment to the entire breast (median 50.00 Gy) and a boost to the primary site (97%) for a median total dose of 60.40 Gy. Results: With a median follow-up of 5.3 years, three patients developed a recurrence in the treated breast. The median interval to recurrencreast. The median interval to recurrence was 8.8 years and all were invasive cancers. Two (67%) occurred outside the initial quadrant. The 5- and 10-year actuarial rates of recurrence were 1 and 15%. Cause-specific survival was 100% at 5 and 10 years. Contralateral breast cancer developed in two patients. There were too few failures for statistical significance to be achieved with any of the following factors: patient age, family history, race, mammographic findings, location primary, pathologic size, histologic subtype, re excision, or final margin status. However, young age, positive or close margins, and the presence of a mass without calcifications had a trend for an increased risk of recurrence. There were no recurrences in the subset of 16 patients who would be candidates for surveillance by Lagios' criteria. Conclusion: For selected patients, conservative surgery and radiation for mammographically detected DCIS results in a low risk of recurrence in the treated breast and 100% 5- and 10-year cause-specific survival. Improved mammographic and pathologic evaluation results in better patient selection and reduces the risk of the subsequent appearance of DCIS in the biopsy site. The identification of risk factors for an ipsilateral invasive breast recurrence is evolving

371

A comparison of moving object detection methods for real-time moving object detection  

Science.gov (United States)

Moving object detection has a wide variety of applications from traffic monitoring, site monitoring, automatic theft identification, face detection to military surveillance. Many methods have been developed across the globe for moving object detection, but it is very difficult to find one which can work globally in all situations and with different types of videos. The purpose of this paper is to evaluate existing moving object detection methods which can be implemented in software on a desktop or laptop, for real time object detection. There are several moving object detection methods noted in the literature, but few of them are suitable for real time moving object detection. Most of the methods which provide for real time movement are further limited by the number of objects and the scene complexity. This paper evaluates the four most commonly used moving object detection methods as background subtraction technique, Gaussian mixture model, wavelet based and optical flow based methods. The work is based on evaluation of these four moving object detection methods using two (2) different sets of cameras and two (2) different scenes. The moving object detection methods have been implemented using MatLab and results are compared based on completeness of detected objects, noise, light change sensitivity, processing time etc. After comparison, it is observed that optical flow based method took least processing time and successfully detected boundary of moving objects which also implies that it can be implemented for real-time moving object detection.

Roshan, Aditya; Zhang, Yun

2014-06-01

372

Statistical methods for polyploid radiation hybrid mapping.  

Science.gov (United States)

Radiation hybrid mapping is a somatic cell technique for ordering genetic loci along a chromosome and estimating physical distances between adjacent loci. This paper presents a model of fragment generation and retention for data involving two or more copies of the chromosome of interest per clone. Such polyploid data can be generated by initially irradiating normal diploid cells or by pooling haploid or diploid clones. The current model assumes that fragments are generated in the ancestral cell of a clone according to an independent Poisson breakage process along each chromosome. Once generated, fragments are independently retained in the clone with a common retention probability. On the basis of this and less restrictive retention models, statistical criteria such as minimum obligate breaks, maximum likelihood ratios, and Bayesian posterior probabilities can be used to decide locus order. Distances can be estimated by maximum likelihood. Likelihood computation is particularly challenging, and computing techniques from the theory of hidden Markov chains prove crucial. Within this context it is possible to incorporate typing errors. The statistical tools discussed here are applied to 14 loci on the short arm of human chromosome 4. PMID:9132268

Lange, K; Boehnke, M; Cox, D R; Lunetta, K L

1995-09-01

373

Cationic membrane obtained by radiation grafting method  

International Nuclear Information System (INIS)

A study has been made for the preparation of ion-containing reverse osmosis membranes by the radiation grafting of aqueous acrylic acid onto low density polyethylene films followed by alkaline treatment to confer ionic character in the prepared membranes. The appropriate reaction conditions were selected under which the graft polymerization was carried out successfully. In this grafting system ammonium ferrous sulphate (Mohr's salt) was used as inhibitor to minimize the homopolymerization of AAc, and a suitable concentration of the inhibitor to be added to the reaction medium was found to be 2.5 wt%. The effect of aqueous monomer concentration on the rate and degree of grafting was studied. The dependence of the grafting rate on the monomer concentration was found to be 0.8 order, i.e. almost first order dependence. It was also found that the irradiation atmosphere (air and nitrogen gas) had no significant effect on the grafting yield at given reaction conditions. The prepared graft copolymer films showed good thermal and chemical stability. Gel determination in the grafted films was also investigated and the results indicated that a crosslinked network structure may be formed. The extent of the gelled part in the graft copolymer increased as the degree of grafting increased. (author)

374

Two-Dimensional Change Detection Methods Remote Sensing Applications  

CERN Document Server

Change detection using remotely sensed images has many applications, such as urban monitoring, land-cover change analysis, and disaster management. This work investigates two-dimensional change detection methods. The existing methods in the literature are grouped into four categories: pixel-based, transformation-based, texture analysis-based, and structure-based. In addition to testing existing methods, four new change detection methods are introduced: fuzzy logic-based, shadow detection-based, local feature-based, and bipartite graph matching-based. The latter two methods form the basis for a

Ilsever, Murat

2012-01-01

375

Extragalactic filament detection with a layer smoothing method  

CERN Document Server

Filaments are clearly visible in galaxy distributions, but they are hardly detected by computer algorithms. Most methods of filament detection can be used only with numerical simulations of a large-scale structure. New simple and effective methods for the real filament detection should be developed. The method of a smoothed galaxy density field was applied in this work to SDSS data of galaxy positions. Five concentric radial layers of 100 Mpc are appropriate for filaments detection. Two methods were tested for the first layer and one more method is proposed.

Tugay, Anatoliy V

2014-01-01

376

Efficient real-time detection of terahertz pulse radiation based on photoacoustic conversion by carbon nanotube nanocomposite  

Science.gov (United States)

Terahertz sensing plays an important role in industry, biology and material science. Most existing techniques for terahertz detection either require bulky optics or need cryogenic cooling, and the uncooled thermal detectors usually suffer from long integration times (1-1,000 ms). We propose, and experimentally demonstrate, a novel scheme based on photoacoustic detection of terahertz pulse radiation. The transient and localized heating in a carbon nanotube-polymer composite by the absorption of terahertz pulse energy produces ultrasound, which is subsequently detected by a highly sensitive acoustic sensor. In contrast to conventional thermal detectors utilizing continuous heat integration, this new method of terahertz detection responds to the energy of each individual terahertz pulse by a time-gated scheme, thus rejecting the continuous radiation from the ambient. In addition, this novel detector possesses advantages such as room-temperature operation, a fast response (~0.1 µs) allowing real-time detection, compact size (millimetre scale) and wide spectral response.

Chen, Sung-Liang; Chang, You-Chia; Zhang, Cheng; Ok, Jong G.; Ling, Tao; Mihnev, Momchil T.; Norris, Theodore B.; Guo, L. Jay

2014-07-01

377

Optimization of radiation monitoring methods of environment  

International Nuclear Information System (INIS)

Full text : Report is devoted to the substantiation of the ways to optimize methods of providing radioecological monitoring (RM) in Ukraine. For this purpose the design features of RM at different levels, the analysis of modern requirements for the RM, the methods for RM ensuring were considered in the dissertation, the use for instrumentation supply of laboratories of new simplified methods, that were developed in this paper, was proposed. This work proposed to strengthen radiobiological component of monitoring, the advantages and disadvantages of the proposed methods were analyzed. The research of the spatial and vertical distribution of radionuclides in soils of the most polluted part of the Chernobyl zone was conducted using the proposed methods. For the first time the parameters of vertical migration of the isotopes 154Eu, 238-240Pu and 241Am in soil profiles of Ch NPP close zone were calculated. The parameters of vertical migration of 90Sr, 137Cs were refined. The calculations of effective environmental and semi-refined periods of above mentioned isotopes for different soil types were conducted, the estimation of dose rates to biota was done, and radioecological characterization of the test sites of the cooling pond was conducted. The features of radioecology of birds, rodents and shrews, bats and amphibians were studied. The dose rates for these species were assessed and their compliance with 103 ICRP Guiding. The species differences in the pollution of wild roes differences in the pollution of wild rodents, insectivores, passerine birds, amphibians and bats on a large amount of factual material were estimated. The investigation of the radioecological contamination of the features of the urbanized landscape was conducted on the example of Pripyat silty. The practical significance of the work is that the developed methods of non radiochemical determination of radiostrontium activity, alpha emitting isotopes of plutonium, which can significantly hasten and facilitate the evaluation of the corresponding concentration radionuclides in the environment, and significantly reduce economic costs. The method of intra vital measurement of 90Sr in small animals opens up fundamentally new opportunities for researchers in radioecology and radiobiology

378

Approximate design calculation methods for radiation streaming in shield irregularities  

Energy Technology Data Exchange (ETDEWEB)

Investigation and assessment are made for approximate design calculation methods of radiation streaming in shield irregularities. Investigation is made for (1) source, (2) definition of streaming radiation components, (3) calculation methods of streaming radiation, (4) streaming formulas for each irregularity, (5) difficulties in application of streaming formulas, etc. Furthermore, investigation is made for simple calculation codes and albedo data. As a result, it is clarified that streaming calculation formulas are not enough to cover various irregularities and their accuracy or application limit is not sufficiently clear. Accurate treatment is not made in the formulas with respect to the radiation behavior for slant incidence, bend part, offset etc., that results in too much safety factors in the design calculation and distrust of the streaming calculation. To overcome the state and improve the accuracy of the design calculation for shield irregularities, it is emphasized to assess existing formulas and develop better formulas based on systematic experimental studies. (author)

Miura, Toshimasa; Hirao, Yoshihiro [Ship Research Inst., Mitaka, Tokyo (Japan); Yoritsune, Tsutomu

1997-10-01

379

Curve fitting methods for solar radiation data modeling  

International Nuclear Information System (INIS)

This paper studies the use of several type of curve fitting method to smooth the global solar radiation data. After the data have been fitted by using curve fitting method, the mathematical model of global solar radiation will be developed. The error measurement was calculated by using goodness-fit statistics such as root mean square error (RMSE) and the value of R2. The best fitting methods will be used as a starting point for the construction of mathematical modeling of solar radiation received in Universiti Teknologi PETRONAS (UTP) Malaysia. Numerical results indicated that Gaussian fitting and sine fitting (both with two terms) gives better results as compare with the other fitting methods

380

Curve fitting methods for solar radiation data modeling  

Science.gov (United States)

This paper studies the use of several type of curve fitting method to smooth the global solar radiation data. After the data have been fitted by using curve fitting method, the mathematical model of global solar radiation will be developed. The error measurement was calculated by using goodness-fit statistics such as root mean square error (RMSE) and the value of R2. The best fitting methods will be used as a starting point for the construction of mathematical modeling of solar radiation received in Universiti Teknologi PETRONAS (UTP) Malaysia. Numerical results indicated that Gaussian fitting and sine fitting (both with two terms) gives better results as compare with the other fitting methods.

Karim, Samsul Ariffin Abdul; Singh, Balbir Singh Mahinder

2014-10-01

381

Electric Insulation Detection Method for High-voltage Insulators  

OpenAIRE

The principle of partial discharge detection is that through partial bridged discharge under high voltage electric field, it detects the inner air-filled cavity of high-voltage insulators. And it is a nondestructive detection method based on discharge magnitude to judge the insulation quality. The detecting system that adopts the partial discharge detection is more rigorous than testing system for electricity products, which must have small discharge capacity and higher sensitivity. This...

Wang Jiajun; Hong Bin; Wang Hongmei

2013-01-01

382

Method for non-invasive detection of ocular melanoma  

International Nuclear Information System (INIS)

There is described an apparatus and method for diagnosing ocular cancer that is both non-invasive and accurate which comprises two radiation detectors positioned before each of the patient's eyes which will measure the radiation level produced in each eye after the administration of a tumor-localizing radiopharmaceutical such as gallium-67

383

Method for non-invasive detection of ocular melanoma  

Science.gov (United States)

There is described an apparatus and method for diagnosing ocular cancer that is both non-invasive and accurate which comprises two radiation detectors positioned before each of the patient's eyes which will measure the radiation level produced in each eye after the administration of a tumor-localizing radiopharmaceutical such as gallium-67.

Lambrecht, Richard M. (Quogue, NY); Packer, Samuel (Floral Park, NY)

1984-01-01

384

Alternative method of generation of Cerenkov radiation or shock wave  

OpenAIRE

An alternative method of generation of Cerenkev radiation is proposed over here with the help of a rotating source and a reflector. The principle is that, if we focus a narrow beam of light on to source of light is rotated with certain angular velocity then the light spot on the surface will move with very high velocity which may exceed the velocity of light. As a consequence of this we shall observe an effect very similar to Cerknov radiation.

Halder, Amit

1997-01-01

385

Interpolation methods and their use in radiation protection  

International Nuclear Information System (INIS)

The presentation summarizes results of using various interpolation methods for getting spatial data from point measurements. These methods were evaluated within the State Office for Nuclear Safety (SONS) Science and Research Project No. 2/2008 'Methods and Measures to Limit Generation and Liquidation of Consequences of Radioactive Matter Misuse by Terrorists'. Several field tests in which the short life-time radioactive matter was released by explosion were realized and the measured data were processed. The essential goal is to find the most realistic method for radiation events assessment. Within the research project, three methods were used: Multilevel B-Spline, Triangulation and Kriging, using freely available SAGA GIS software. The best solution for this sort of radiation events appears to be the Multilevel B-Spline method. It is quick and produces good quality output data comparable with the much slower Kriging method and allows extrapolation in contrast to Triangulation. (author)

386

A method of detecting radio transients  

OpenAIRE

Radio transients are sporadic signals and their detection requires that the backends of radio telescopes be equipped with the appropriate hardware and software to undertake this. Observational programs to detect transients can be dedicated or they can piggy-back on observations made by other programs. It is the single-dish single-transient (non-periodical) mode which is considered in this paper. Because neither the width of a transient nor the time of its arrival is known, a...

Fridman, P. A.

2010-01-01

387

Analysis on Credit Card Fraud Detection Methods  

OpenAIRE

Due to the theatrical increase of fraud which results in loss of dollars worldwide each year, several modern techniques in detecting fraud are persistently evolved and applied to many business fields. Fraud detection involves monitoring the activities of populations of users in order to estimate, perceive or avoid undesirable behavior. Undesirable behavior is a broad term including delinquency, fraud, intrusion, and account defaulting. This paper presents a survey of current techniques used i...

Renu; De, Suman

2014-01-01

388

Anomaly-based Network Intrusion Detection Methods  

OpenAIRE

The article deals with detection of network anomalies. Network anomalies include everything that is quite different from the normal operation. For detection of anomalies were used machine learning systems. Machine learning can be considered as a support or a limited type of artificial intelligence. A machine learning system usually starts with some knowledge and a corresponding knowledge organization so that it can interpret, analyse, and test the knowledge acquired. There are several machine...

Pavel Nevlud; Miroslav Bures; Lukas Kapicak; Jaroslav Zdralek

2013-01-01

389

Detection limits of absorbed dose of ionizing radiation in molluscan shells as determined by e.p.r. spectroscopy  

International Nuclear Information System (INIS)

The exposure of waters to ionizing radiation from radionuclides imprisoned in dumped nuclear waste containers, freed in nuclear submarine accidents or released in underwater magma eruptions are difficult to be evaluated by conventional radiometric methods. Ionizing radiation evokes stable paramagnetic centers in crystalline lattice of mineral components in bone skeletons of mammals and fishes as well as in exoskeletons of mollusca. They give rise in e.p.r. to specific, extremely stable signals which are proposed to be applied as indicators of radiation exposure levels. In the present study the e.p.r. detection limits of the dose of ionizing radiation absorbed in shells of fresh water and marine mollusca (selected species) have been estimated. It has been found that with fresh water mollusca the dose of 1-2 Gy can be detected, while the sea water mollusca by one order of magnitude lower, i.e. about 0.1 Gy. (author)

390

Pathoanatomy of acute radiation syndrome treated by modern methods  

International Nuclear Information System (INIS)

Changes in morphological picture of acute radiation disease under the effects of modern treatment are studied. 28 case histories of patients exposed to gamma radiation at dose of 6 - 18 Gy are analyzed post mortem. Due to treatment, signs of bone marrow reparation are detected even in patients with the most severe forms. The enteric syndrome was alleviated, and partial epithelialisation of the oral cavity and throat was attained. The hemorrhagic syndrome manifested, in the majority of cases, was no longer life threatening. The most frequent causes of death were infectious complications, primarily mycotic and viral

391

Nuisance Source Population Modeling for Radiation Detection System Analysis  

International Nuclear Information System (INIS)

A major challenge facing the prospective deployment of radiation detection systems for homeland security applications is the discrimination of radiological or nuclear 'threat sources' from radioactive, but benign, 'nuisance sources'. Common examples of such nuisance sources include naturally occurring radioactive material (NORM), medical patients who have received radioactive drugs for either diagnostics or treatment, and industrial sources. A sensitive detector that cannot distinguish between 'threat' and 'benign' classes will generate false positives which, if sufficiently frequent, will preclude it from being operationally deployed. In this report, we describe a first-principles physics-based modeling approach that is used to approximate the physical properties and corresponding gamma ray spectral signatures of real nuisance sources. Specific models are proposed for the three nuisance source classes - NORM, medical and industrial. The models can be validated against measured data - that is, energy spectra generated with the model can be compared to actual nuisance source data. We show by example how this is done for NORM and medical sources, using data sets obtained from spectroscopic detector deployments for cargo container screening and urban area traffic screening, respectively. In addition to capturing the range of radioactive signatures of individual nuisance sources, a nuisance source population model must generate sources with a frequency of occurrence consiurces with a frequency of occurrence consistent with that found in actual movement of goods and people. Measured radiation detection data can indicate these frequencies, but, at present, such data are available only for a very limited set of locations and time periods. In this report, we make more general estimates of frequencies for NORM and medical sources using a range of data sources such as shipping manifests and medical treatment statistics. We also identify potential data sources for industrial source frequencies, but leave the task of estimating these frequencies for future work. Modeling of nuisance source populations is only useful if it helps in understanding detector system performance in real operational environments. Examples of previous studies in which nuisance source models played a key role are briefly discussed. These include screening of in-bound urban traffic and monitoring of shipping containers in transit to U.S. ports.

392

Electric Insulation Detection Method for High-voltage Insulators  

Directory of Open Access Journals (Sweden)

Full Text Available The principle of partial discharge detection is that through partial bridged discharge under high voltage electric field, it detects the inner air-filled cavity of high-voltage insulators. And it is a nondestructive detection method based on discharge magnitude to judge the insulation quality. The detecting system that adopts the partial discharge detection is more rigorous than testing system for electricity products, which must have small discharge capacity and higher sensitivity. This paper describes the principles of partial discharge detection and analysis insulation detection.

Wang Jiajun

2013-07-01

393

Method for detecting software anomalies based on recurrence plot analysis  

OpenAIRE

Presented paper evaluates method for detecting software anomalies based on recurrence plot analysis of trace log generated by software execution. Described method for detecting software anomalies is based on windowed recurrence quantification analysis for selected measures (e.g. Recurrence rate - RR or Determinism - DET). Initial results show that proposed method is useful in detecting silent software anomalies that do not result in typical crashes (e.g. exceptions).

Micha? Mosdorf

2012-01-01

394

Method for detecting software anomalies based on recurrence plot analysis  

Directory of Open Access Journals (Sweden)

Full Text Available Presented paper evaluates method for detecting software anomalies based on recurrence plot analysis of trace log generated by software execution. Described method for detecting software anomalies is based on windowed recurrence quantification analysis for selected measures (e.g. Recurrence rate - RR or Determinism - DET. Initial results show that proposed method is useful in detecting silent software anomalies that do not result in typical crashes (e.g. exceptions.

Micha? Mosdorf

2012-03-01

395

Development of thin dosemeters of CaSO4: Dy for beta radiation detection  

International Nuclear Information System (INIS)

Thin pellets of CaSO: Dy (0,20mm) were produced and tested in beta radiation fields. The Thermolumiscent (TL) characteristics studied were sensitivity, reproducibility, lower detection limit, linearity of TL response with absorved dose energy dependence. The results show the usefulness of this thin pellets in beta radiation detection. (Author)

396

Development of Remote Control Laboratory for Radiation Detection via Internet  

International Nuclear Information System (INIS)

The role of experiments in science education is essential for understanding the natural phenomena and principle related to a subject. Therefore, the remote control experiment via Internet is one of key solution for distance learners in science education. The remote experiments are also necessary for the time-consuming experiment which takes several days, collaborative experiment between distance learners, expensive laboratory equipment which is not usually available to students, experimental procedure which is dangerous, etc. In this study, we have developed a general method for a remote control laboratory system using internet and interface techniques. It is possible for students to learn the nuclear physics to control the real instruments and conduct physics experimentation with internet techniques. We proposed the remote control radiation measurement system as a sample application. This system could be useful for the monitoring near a nuclear power plants in order to improve the environment data credibility to the public

397

New method for detecting degradation in installed cables in nuclear power plants  

International Nuclear Information System (INIS)

Simple and precise methods for detecting degradation in installed cables in nuclear power plants are expected to develop from the viewpoint of the safety operation and the life extension of the plants. Generally, the degradation of cable insulation by thermal and/or radiation aging has been examined by tensile tests, and the degree of degradation was evaluated from the ultimate strength and elongation. The degradation of cables installed in the facility is likely to be detected by non-destructive techniques. For this purpose, two kinds of detecting methods i.e., (a) torque-strain response and (b) thermal gravimetry were studied in order to apply to the low voltage cables, for which effective detecting methods have not been completed. The paper describes a basic idea to determine degradation of the low voltage CV-cables (polyethylene insulation, polyvinylchloride jacket). Elongation at break was used as a primary standard to evaluate availability of the methods

398

[ARMS-PCR method for detecting multiple NPM1 mutations].  

Science.gov (United States)

This study was aimed to establish a simple, sensitive detection method for multiple NPM1 mutations, so as to reduce the omission ratio of NMP1 mutant detection. Recombinant plasmids containing wide-type NPM1 and the most common mutations (A, B, C, D) were constructed as the detection objects. The ARMS-PCR for detecting multiple NPM1 mutations was established through designing a pair of specific primers whose 3' end base matched with four mutants (A,B,C,D), but did not matched with wild type NPM1 according to the different base sequence of NPM1 mutants. The feasibility of the ARMS-PCR method was evaluated by assessing the detection range and the sensitivity and comparing with direct sequencing. The results showed that the recombinant plasmids were constructed successfully by restriction analysis and DNA sequencing. The four mutants but not wild type NPM1 were detected by using ARMS-PCR, the detection range of the method was 10(3) copies/ml -10(9) copies/ml and the sensitivity was 0.01%, while the direct sequencing method could not detect the mutations if mutation was less than 10%. It is concluded that the high sensitive ARMS-PCR is established for detecting the four mutations of NPM1 and more than 95% mutants can be detected by this method, providing a new detection method for clinical NPM1 gene mutant. PMID:23998612

Jian, Zheng-Wei; Xu, Fen; Shi, Cong; Wan, La-Gen; Zhang, Zhang-Lin

2013-08-01

399

Evaluation of mass spectrometry and radiation detection for the analysis of radionuclides  

International Nuclear Information System (INIS)

Radioactive elements are of increasing importance in the areas of human health and safety, the environment, use in terrorism, and nuclear nonproliferation. Accurate and sensitive measurement of fission products, medical isotopes, and actinide species are a vital part of the job entrusted to the national laboratories. Several competing techniques exist. They can be mainly summarized into two categories: radiation and mass spectrometric detection methods. Traditional radiometric counting methods, which are based on the measurement of natural decay of radionuclides, play an important role in the detection of radionuclides. Fission track analysis, which uses thermal neutron induced fission to detect fissionable isotopes, now reaches a limit of detection (LOD) of 106 atoms. Of the mass spectrometric detection techniques, inductively coupled plasma mass spectrometry, provides the best sensitivity for the cost in low-level determinations of long-lived radionuclides. Other methods, such as thermal ionization mass spec and accelerator mass spec can provide greater sensitivity in some cases but the cost is higher. Depending on the types of mass analyzers, LOD varies from ng/l to pg/l. More importantly, mass spectrometry is capable of offering precise isotopic ratio information that may act as a fingerprint for identifying the origins of nuclear materials. As the technology matures mass techniques now can provide suitable detection of the shorter-lived isotopes. This ction of the shorter-lived isotopes. This criterion is critical as the prompt determination of radionuclides is becoming of overriding importance. Radiometric information displayed in a manner that allows for easy comparison to mass counting is provided. The information can then be used as a general guide to determine the most suitable method to use for the prompt determination of radionuclides. (author)

400

Aging masks detection of radiation-induced brain injury  

OpenAIRE

Fractionated partial or whole-brain irradiation (fWBI) is a widely used, effective treatment for primary and metastatic brain tumors, but it also produces radiation-induced brain injury, including cognitive impairment. Radiation-induced neural changes are particularly problematic for elderly brain tumor survivors who also experience age-dependent cognitive impairment. Accordingly, we investigated, i] radiation-induced cognitive impairment, and ii] potential biomarkers of radiation-induced bra...

Shi, Lei; Olson, John; D’agostino, Ralph; Linville, Constance; Nicolle, Michelle M.; Robbins, Michael E.; Wheeler, Kenneth T.; Brunso-bechtold, Judy K.

2011-01-01

401

Development and Establishment of Detection Method of Irradiated Foods  

International Nuclear Information System (INIS)

The present project was related to the development and establishment of the detection techniques for the safety management of gamma-irradiated food and particularly conducted for the establishment of standard detection method for gamma-irradiated dried spices and raw materials, dried meat and fish powder for processed foods, bean paste powder, red pepper paste powder, soy sauce powder, and starch for flavoring ingredients described in 3, 6, 7 section of Korean Food Standard. Since the approvement of gamma-irradiated food items will be enlarged due to the international tendency for gamma-irradiated food, it was concluded that the establishment of detailed detection methods for each food group is not efficient for the enactment and enforcement of related regulations. For this reason, in order to establish the standard detection method, a detection system for gamma-irradiated food suitable for domestic operation was studied using comparative analysis of domestic and foreign research data classified by items and methods and European Standard as a reference. According to the comparative analyses of domestic and foreign research data and regulations of detection for gamma-irradiated food, it was concluded to be desirable that the optimal detection method should be decided after principal detection tests such as physical, chemical, and biological detection methods are established as standard methods and that the specific descriptions such as pre-treatment of raw materials, test methods, and the evaluation of results should be separately prescribed

402

Development and Establishment of Detection Method of Irradiated Foods  

Energy Technology Data Exchange (ETDEWEB)

The present project was related to the development and establishment of the detection techniques for the safety management of gamma-irradiated food and particularly conducted for the establishment of standard detection method for gamma-irradiated dried spices and raw materials, dried meat and fish powder for processed foods, bean paste powder, red pepper paste powder, soy sauce powder, and starch for flavoring ingredients described in 3, 6, 7 section of Korean Food Standard. Since the approvement of gamma-irradiated food items will be enlarged due to the international tendency for gamma-irradiated food, it was concluded that the establishment of detailed detection methods for each food group is not efficient for the enactment and enforcement of related regulations. For this reason, in order to establish the standard detection method, a detection system for gamma-irradiated food suitable for domestic operation was studied using comparative analysis of domestic and foreign research data classified by items and methods and European Standard as a reference. According to the comparative analyses of domestic and foreign research data and regulations of detection for gamma-irradiated food, it was concluded to be desirable that the optimal detection method should be decided after principal detection tests such as physical, chemical, and biological detection methods are established as standard methods and that the specific descriptions such as pre-treatment of raw materials, test methods, and the evaluation of results should be separately prescribed.

Byun, Myung Woo; Lee, Ju Woon; Kim, Dong Ho; Jo, Cheo Run; Kim, Jang Ho; Kim, Kyong Su

2004-12-15

403

Methods of Measurement and Interpretation of Results in Radiation Monitoring and Dosimetry  

International Nuclear Information System (INIS)

Both new and old methods of radiation measurement may find application in any well planned radiation monitoring and dosimetry program. The original ionization chamber method» for radiation detection and measurement have proven to be dependable, accurate and attainable at reasonable costs. Recent instrumentation advances, utilizing scintillation crystals and tissue-equivalent detectors, provide special capabilities for special monitoring problems. Moderated BF3, counters and scintillation crystal counters have led to advances In neutron dose-rate monitoring, but further improvements in full energy spectrum neutron monitoring capabilities remain to be developed. High-energy particle dosimetry Is perhaps most practically attained through the use of tissue-equivalent ionization chambers. Interpretation of Instrument readings requires consideration of the exposure geometry, the incident radiation energy, the radiation types present and the duration of the exposure. A knowledge of the temperature and barometric pressure may also be required. Additionally, to provide accurate interpretations of instrument readings, the operational characteristics of the Instruments used and the geometry and radiation properties of the sources used in the instrument calibrations need to be known. Methods of calibration may revert to the primary calibration technique where some nationally certified radiation sources or dose-measuring instruments are used under prescribed exposure gents are used under prescribed exposure geometries, or secondary calibrations may be obtained through the use of radiation sources and well designed calibration exposure Jigs. Radionuclide sources, X-ray machines and various particle accelerators may find an application in providing for instrument calibration. The geometry of Instrument calibration needs to be carefully considered. It should approximate that encountered when the instrument is used or be defined so that appropriate correction factors may be applied and accurate Instrument reading interpretations made. Instrument radiation measurements and reading Interpretations can be no better than the quality of the Instrument calibration. (author)

404

Methods and procedures for external radiation dosimetry at ORNL  

International Nuclear Information System (INIS)

Procedures, methods, materials, records, and reports used for accomplishing the personnel, external radiation monitoring program at Oak Ridge National Laboratory are described for the purpose of documenting what is done now for future reference. This document provides a description of the methods and procedures for external radiation metering, monitoring, dosimetry, and records which are in effect at ORNL July 1, 1981. This document does not include procedures for nuclear accident dosimetry except insofar as routine techniques may apply also to nuclear accident dosimetry capability

405

Method for decreasing radiation load in puva therapy  

Energy Technology Data Exchange (ETDEWEB)

An improved method is described for treating a psoriatic subject undergoing treatment with a psoralen in conjection with ultraviolet A radiation of from wavelength of 3200 to 4000 angstroms. The improved method comprises prior to initiation of the treatment, pretreating the subject for a period of from 4 to 10 days with an effective amount of an anti-psoriatic polyene compound, and thereafter initiating the treatment with a psoralen in conjunction with ultraviolet A radiation and continuing the treatment concurrently with the administration of the anti-psoriatic polyene compound.

Wolff, K.

1987-02-10

406

Method of Object Detection for Mobile Robot  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement: In general, there are two steps of object detection, which are object generation, where the locations of possible objects are in an image and object verification, where tests are performed to verify the presence of object in an image. Approach: The purpose of the proposed object recognition system was to detect the object which is in front the mobile robot so that it can send warnings to avoid possible collision. The information of detected objects can also help to control the robot to travel at an appropriate speed and direction to avoid possible collisions. Results: An object in an image was detected by the two steps of image generation and verification. When object localizations were hypothesized, sub-image of the object was extracted from the image. Gabor features extracted from the sub-image is input into the classifier to verify whether the hypothesized sub-image contain an object or not. Conclusion: Localizations of objects in image are generated and verified. Object generation was implemented by using horizontal and vertical edges on the way region of interest segmented by utilizing color information. The sub-images of object are verified by classifier trained on Gabor features of a training set of images.

Surachai Panich

2010-01-01

407

Detected power and linewidth of Josephson self-radiation from frequency-locked and microwave-coupled YBa2Cu3Oy arrays in a waveguide detection system  

International Nuclear Information System (INIS)

Frequency-locked and microwave-coupled arrays of high-Tc superconducting Josephson junctions have been developed. The YBa2Cu3Oy Josephson junctions were prepared on bicrystal MgO substrates using a pulsed laser ablation method. The maximum detected power of Josephson self-radiation, which is directly detected by a superheterodyne receiver with a central frequency of 22 GHz, from the arrays was enhanced with increasing number of Josephson junctions. The Josephson self-radiation properties of the arrays revealed a good quality of frequency locking and exactly satisfied the Josephson voltage-frequency relationship. A narrower linewidth of the Josephson self-radiation was obtained by increasing the number of Josephson junctions in the array. (author)

408

X-spectrographic method for plutonium detection. Application to contamination measurements in humans  

International Nuclear Information System (INIS)

After reviewing the radio-toxicology of plutonium 239 and conventional detection methods using its ?-radiation, the author considers the measurement of the X emission spectrum of plutonium 239 using a proportional counter filled with argon under pressure. This preliminary work leads to the third part of this research involving the detailed study of the possibilities of applying thin alkali halide crystal scintillators to the detection of soft plutonium X-rays; there follows a systematic study of all the parameters liable to render the detection as sensitive as possible: movement due to the photomultiplier itself and its accessory electronic equipment, nature and size of the crystal scintillator as well as its mode of preparation, shielding against external parasitic radiation. Examples of some applications to the measurement of contamination in humans give an idea of the sensitivity of this method. (author)

409

Method for the detection of turbulences in a flowing medium  

International Nuclear Information System (INIS)

A method is presented for the detection of turbulences in a flowing medium, that are not influenced by the general fluid velocity. A laser beam is directed to the fluid and, with the help of the homodyne effect, frequency changes of the reflected light are detected through self beating. The detection of turbulences on an airport runway is described as an example. (RW)

410

Edge Detection Using Morphological Method and Corner Detection Using Chain Code Algorithm  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper we show a very good approach to detect edge and corner of any image. Edges and corners are very important part of an image .In our present days edge and corner detections is very essential for object identification. In this paper we show edge detection using morphological method and corner detection using chain code algorithm. This two method can work on any type of image.

Anjan Bikash Maity

2011-07-01

411

Use of microorganisms for detection of Vavilov-Cherenkov radiation  

International Nuclear Information System (INIS)

The discovery of the photoreactivation effect following irradiation of E. coli cells with ionizing radiation and its experimental and theoretical study has revealed the essential role of Vavilov-Cherenkov radiation in the lethal and mutagenic action of ionizing radiation. It has been shown that the photoreactivation effect in microorganism cells can be successfully used for evaluation of the contribution of the processes of electronic excitation of molecules, being initiated by the Vavilov-Cherenkov radiation and of the direct interaction with secondary electrons, to the biological effects of ionizing radiations. (orig.)

412

Weak Signal Frequency Detection Method Based on Generalized Duffing Oscillator  

International Nuclear Information System (INIS)

The sensitive characteristic to the initial value of chaos system sufficiently demonstrates the superiority in weak signal parameters detection. Analyzing the current chaos-based frequency detection method, a novel generalized Duffing equation is proposed to detect weak signal frequency. By choosing a suitable adjusting factor, when the outside driving force frequency is equal to that of the detected signal, the generalized Duffing oscillator is in great period state, which can obtain the frequency information of the detected signal. The simulation results indicate this method is rapidly convenient and shows better accuracy. (general)

413

A method of providing directionality for ionising radiation detectors — RadICAL  

Science.gov (United States)

A novel method for providing directionality for radiation detection is presented. The idea is based upon the fact that detector response depends upon two properties of the active component in the detector: the radiation pathlength and the area presented to a particle flux. Thus a rotating slab of detector gives a characteristic temporal response that can be used to identify the direction of the photon flux. A model of the detector system is used to design and build a detector which is then evaluated. It is shown that a rotating detector of this nature can produce a characteristic curve which can be used to determine the location of a single stationary point source.

Randall, G. L.; Iglesis, E.; Wong, H. F.; Speller, R. S.

2014-10-01

414

Particle Methods for Simulating Atomic Radiation in Hypersonic Reentry Flows  

Science.gov (United States)

With a fast reentry speed, the Stardust vehicle generates a strong shock region ahead of its blunt body with a temperature above 60,000 K. These extreme Mach number flows are sufficiently energetic to initiate gas ionization processes and thermal and chemical ablation processes. The nonequilibrium gaseous radiation from the shock layer is so strong that it affects the flowfield macroparameter distributions. In this work, we present the first loosely coupled direct simulation Monte Carlo (DSMC) simulations with the particle-based photon Monte Carlo (p-PMC) method to simulate high-Mach number reentry flows in the near-continuum flow regime. To efficiently capture the highly nonequilibrium effects, emission and absorption cross section databases using the Nonequilibrium Air Radiation (NEQAIR) were generated, and atomic nitrogen and oxygen radiative transport was calculated by the p-PMC method. The radiation energy change calculated by the p-PMC method has been coupled in the DSMC calculations, and the atomic radiation was found to modify the flow field and heat flux at the wall.

Ozawa, T.; Wang, A.; Levin, D. A.; Modest, M.

2008-12-01

415

GaN heterostructures for biosensing and radiation detection  

Energy Technology Data Exchange (ETDEWEB)

In this thesis I show the results from our investigation of the interface between gallium nitride wide bandgap semiconductor heterostructures and (bio)molecular systems on their surfaces for biosensing, bioelectronics, and photoelectric applications, with a large emphasis on the processes arising from high energy ionizing irradiation, including heterostructure photoelectric gain mechanisms. Wide bandgap semiconductors, such as gallium nitride, have received increasing attention as potential components in advanced organic/inorganic hybrid systems. Working to further this topic, we determine a new semiconductor alignment required for low energy photo-induced charge transfer ionization of alkyl chains well below the energy normally required for molecular cleavage, show original results of the influence of binding methods on enzyme functionality in conjunction with a novel electrochemical and environmental control system and demonstrate new possibilities to significantly improve upon pH measurements through the use of high sensitivity devices. Furthermore, based on the extension of this work to support future studies of radiation effects on cell systems, we present a detailed characterization of new simultaneous chemical sensing and ionizing radiation dosimetry using single devices. We found that their pH sensitivity was retained during X-ray irradiation and that the fundamental characteristics can be used to separate the irradiation signal from the pH response without compromising operational stability. These data provide clear indications of the separate response mechanism tied to the presence of a two-dimensional electron gas channel. Here, we found new results exhibiting exceptionally high gains and independence of the well-known persistent photoconductivity for soft X-rays and high energy particles in the ultralow dose-rate regime. This material system provides the capability for high sensitivity and resolution real time monitoring, which is competitive with and complements state-of-the-art detectors. Thus, is extremely promising for future applications ranging from advanced organic/inorganic hybrid systems to medical imaging.

Howgate, John D.

2012-12-11

416

GaN heterostructures for biosensing and radiation detection  

International Nuclear Information System (INIS)

In this thesis I show the results from our investigation of the interface between gallium nitride wide bandgap semiconductor heterostructures and (bio)molecular systems on their surfaces for biosensing, bioelectronics, and photoelectric applications, with a large emphasis on the processes arising from high energy ionizing irradiation, including heterostructure photoelectric gain mechanisms. Wide bandgap semiconductors, such as gallium nitride, have received increasing attention as potential components in advanced organic/inorganic hybrid systems. Working to further this topic, we determine a new semiconductor alignment required for low energy photo-induced charge transfer ionization of alkyl chains well below the energy normally required for molecular cleavage, show original results of the influence of binding methods on enzyme functionality in conjunction with a novel electrochemical and environmental control system and demonstrate new possibilities to significantly improve upon pH measurements through the use of high sensitivity devices. Furthermore, based on the extension of this work to support future studies of radiation effects on cell systems, we present a detailed characterization of new simultaneous chemical sensing and ionizing radiation dosimetry using single devices. We found that their pH sensitivity was retained during X-ray irradiation and that the fundamental characteristics can be used to separate the irradiation signal from the pH response without compromising operational stability. These data provide clear indications of the separate response mechanism tied to the presence of a two-dimensional electron gas channel. Here, we found new results exhibiting exceptionally high gains and independence of the well-known persistent photoconductivity for soft X-rays and high energy particles in the ultralow dose-rate regime. This material system provides the capability for high sensitivity and resolution real time monitoring, which is competitive with and complements state-of-the-art detectors. Thus, is extremely promising for future applications ranging from advanced organic/inorganic hybrid systems to medical imaging.

417

Detection of formaldehyde in textiles by chromotropic acid method  

OpenAIRE

BACKGROUND: The common causes of textile dermatitis are formaldehyde resins and disperse dyes. There are various methods to detect the presence of formaldehyde in clothing. AIM: To detect the presence of formaldehyde in various types of textiles by the chromotropic acid method and to assess the effect of washing on the formaldehyde content. METHODS: Twenty randomly selected textiles from a local cloth store were tested for formaldehyde by the chromotropic acid method. A purple ring indicated ...

Rao Sanath; Shenoy Shruthakirthi; Davis Suraj; Nayak Sudhakar

2004-01-01

418

Comparison between damage detection methods applied to beam structures  

OpenAIRE

Damage detection methods based on the dynamic measurements of structures are one of the most important techniques for damage evaluation in bridges. The methods considered in this study have been recognized as the most promising tools for damage detection in these structures. Some of these methods were applied during the deliberate damage of Z24 Bridge in Switzerland and I-24 Bridge in USA. These methods have been evaluated in different cases and therefore it is difficult to decide which me...

Salgado, R.; Cruz, Paulo J. S.; Ramos, Lu S. F.; Louren O, Paulo B.

2006-01-01

419

High Density Nano-Electrode Array for Radiation Detection  

International Nuclear Information System (INIS)

Bulk single crystals of Cd1-xZnxTe (x=0.04 to x=0.2) compound semiconductor is used for room temperature radiation detection. The production of large volume of Cd1-xZnxTe with low defect density is expensive. As a result there is a growing research interest in the production of nanostructured compound semiconductors such as Cd1-xZnxTe in an electrochemical route. In this investigation, Cd1-xZnxTe ternary compound semiconductor, referred as CZT, was electrodeposited in the form of nanowires onto a TiO2 nanotubular template from propylene carbonate as the non-aqueous electrolyte, using a pulse-reverse electrodeposition process at 130 C. The template acted as a support in growing ordered nanowire of CZT which acts as a one dimensional conductor. Cyclic Voltammogram (CV) studies were conducted in determining the potentials for the growth of nanowires of uniform stoichiometry. The morphologies and composition of CZT were characterized by using SEM, TEM and XRD. The STEM mapping carried out on the nanowires showed the uniform distribution of Cd, Zn and Te elements. TEM image showed that the nanowires were polycrystalline in nature. The Mott-Schottky analysis carried on the nanowires showed that the nanowires were a p-type semiconductor. The carrier density, band gap and resistivity of the Cd0.9Zn0.1Te nanowires were 4.29 x 1013 cm-3, 1.56 eV and 2.76 x 1011 (Omega)-cm respectively. The high resistivity was attributed to the presence of deep defect states such as cadmium vacancies or Te antisites which were created by the anodic cycle of the pulse-reverse electrodeposition process. Stacks of series connected CZT nanowire arrays were tested with different bias potentials. The background current was in the order of tens of picoamperes. When exposed to radiation source Amerecium-241 (60 KeV, 4 (micro)Ci), the stacked CZT nanowires arrays showed sensing behavior. The sensitivity of the nanowire arrays increased as the number of stacks increased. The preliminary results indicate that the CZT nanowire arrays can be used as a potential X-ray and low energy gamma ray detector material at room temperature with a much low bias potential (0.7-4V) as against 300-500 V applied in the commercial bulk detector materials.

420

High Density Nano-Electrode Array for Radiation Detection  

Energy Technology Data Exchange (ETDEWEB)

Bulk single crystals of Cd1-xZnxTe (x=0.04 to x=0.2) compound semiconductor is used for room temperature radiation detection. The production of large volume of Cd1-xZnxTe with low defect density is expensive. As a result there is a growing research interest in the production of nanostructured compound semiconductors such as Cd1-xZnxTe in an electrochemical route. In this investigation, Cd1-xZnxTe ternary compound semiconductor, referred as CZT, was electrodeposited in the form of nanowires onto a TiO2 nanotubular template from propylene carbonate as the non-aqueous electrolyte, using a pulse-reverse electrodeposition process at 130 ºC. The template acted as a support in growing ordered nanowire of CZT which acts as a one dimensional conductor. Cyclic Voltammogram (CV) studies were conducted in determining the potentials for the growth of nanowires of uniform stoichiometry. The morphologies and composition of CZT were characterized by using SEM, TEM and XRD. The STEM mapping carried out on the nanowires showed the uniform distribution of Cd, Zn and Te elements. TEM image showed that the nanowires were polycrystalline in nature. The Mott-Schottky analysis carried on the nanowires showed that the nanowires were a p-type semiconductor. The carrier density, band gap and resistivity of the Cd0.9Zn0.1Te nanowires were 4.29x1013 cm-3, 1.56 eV and 2.76x1011?-cm respectively. The high resistivity was attributed to the presence of deep defect states such as cadmium vacancies or Te antisites which were created by the anodic cycle of the pulse-reverse electrodeposition process. Stacks of series connected CZT nanowire arrays were tested with different bias potentials. The background current was in the order of tens of picoamperes. When exposed to radiation source Amerecium-241 (60 KeV, 4 ?Ci), the stacked CZT nanowires arrays showed sensing behavior. The sensitivity of the nanowire arrays increased as the number of stacks increased. The preliminary results indicate that the CZT nanowire arrays can be used as a potential X-ray and low energy gamma ray detector material at room temperature with a much low bias potential (0.7 – 4V) as against 300 – 500 V applied in the commercial bulk detector materials.

Mano Misra

2010-05-07

421

Anomaly-based Network Intrusion Detection Methods  

Directory of Open Access Journals (Sweden)

Full Text Available The article deals with detection of network anomalies. Network anomalies include everything that is quite different from the normal operation. For detection of anomalies were used machine learning systems. Machine learning can be considered as a support or a limited type of artificial intelligence. A machine learning system usually starts with some knowledge and a corresponding knowledge organization so that it can interpret, analyse, and test the knowledge acquired. There are several machine learning techniques available. We tested Decision tree learning and Bayesian networks. The open source data-mining framework WEKA was the tool we used for testing the classify, cluster, association algorithms and for visualization of our results. The WEKA is a collection of machine learning algorithms for data mining tasks.

Pavel Nevlud

2013-01-01

422

Methods for cross-language plagiarism detection  

OpenAIRE

Three reasons make plagiarism across languages to be on the rise: (i) speakers of under-resourced languages often consult documentation in a foreign language, (ii) people immersed in a foreign country can still consult material written in their native language, and (iii) people are often interested in writing in a language different to their native one. Most efforts for automatically detecting cross-language plagiarism depend on a preliminary translation, which is not always available. In...

Barro?n Ceden?o, Luis Alberto; Gupta, Parth Alokkumar; Rosso, Paolo

2013-01-01

423

Novel Methods To Detect Membrane Proteins  

Science.gov (United States)

Membrane proteins are critical to numerous biological functions and are the target of nearly all pharmaceuticals. Cloned membrane proteins are often difficult to detect due to the lack of effective antibodies. Moreover, currently available expression vectors lack the signal sequences, tags, and multiple cloning sites to clone membrane proteins and express them on the cell surface. This invention is the first of its kind to contain all of these elements to facilitate biochemical studies on membrane proteins.

424

Studies in damage detection using flexibility method  

OpenAIRE

Structural health monitoring (SHM) is a way of implementing a system that can monitor, and provide data to help engineers secure the integrity of different structures like civil infrastructure, bridges, offshore structures and aerospace structures. The main purpose of SHM is to detect damages in structures before they become so large that they threaten the integrity and the functionality of the structure. After natural disasters like hurricanes and tsunamis, there is always an uncertainty in ...

Andersen, Jan Terje

2012-01-01

425

Detecting community structure in networks using edge prediction methods  

CERN Document Server

Community detection and edge prediction are both forms of link mining: they are concerned with discovering the relations between vertices in networks. Some of the vertex similarity measures used in edge prediction are closely related to the concept of community structure. We use this insight to propose a novel method for improving existing community detection algorithms by using a simple vertex similarity measure. We show that this new strategy can be more effective in detecting communities than the basic community detection algorithms.

Yan, Bowen

2012-01-01

426

A method of detecting radio transients  

CERN Document Server

Radio transients are sporadic signals and their detection requires that the backends of radio telescopes be equipped with the appropriate hardware and software to undertake this. Observational programs to detect transients can be dedicated or they can piggy-back on observations made by other programs. It is the single-dish single-transient (non-periodical) mode which is considered in this paper. Because neither the width of a transient nor the time of its arrival is known, a sequential analysis in the form of a cumulative sum (cusum) algorithm is proposed here. Computer simulations and real observation data processing are included to demonstrate the performance of the cusum. The use of the Hough transform is here proposed for the purpose of non-coherent de-dispersion. It is possible that the detected transients could be radio frequency interferences (RFI) and a procedure is proposed here which can distinguish between celestial signals and man-made RFI. This procedure is based on an analysis of the statistical...

Fridman, P A

2010-01-01

427

A method of detecting radio transients  

Science.gov (United States)

Radio transients are sporadic signals, requiring that the backends of radio telescopes be equipped with the appropriate hardware and software for their detection. Observational programmes for detecting transients can be dedicated to that purpose or can rely upon observations made by other programmes. It is the single-dish single-transient (non-periodical) mode which is considered in this paper. Because neither the width of