WorldWideScience
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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

Bayesian Methods for Radiation Detection and Dosimetry  

International Nuclear Information System (INIS)

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 compartmental activities. From the estimated probability densities of the model parameters we were able to derive the densities for compartmental activities for a two compartment catenary model at different times. We also calculated the average activities and their standard deviation for a simple two compartment model

4

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)

5

High-energy radiation detector and method of detection  

International Nuclear Information System (INIS)

A high-energy radiation detector is described comprising: means for detecting a predetermined type of high-energy radiation and transforming the detected radiation into light, the means for detecting having a first and second end; means for generating an electric signal based upon the amount of light directed thereon and for outputting the signal; an optical window means optically coupled to the first end of the detecting means for channeling the light therefrom into the generating means, the optical window being composed of material having a predetermined amount of heavy metal therein; a collimator made of heavy metal disposed at the second end of the detecting means, the collimator having an open end to admit the high energy radiation onto the second end of the detecting means; means for shielding composed of heavy metal and being exclusively limited to and covering the detecting means other than the first and second ends of the detecting means and limited to and covering portions of the optical window, and the weight of the radiation detector being minimized due to the limited extent of the shielding means; and means for supporting the detecting means, the generating means, the optical window, the collimator and the shielding means; wherein the means for detecting is shielded from high-energy radiation on all sides by the optical window and the means for shielding except for the second end adjacent the collimator and the means for supporting does not shield high-enans for supporting does not shield high-energy radiation from components internal thereto

6

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

Science.gov (United States)

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

7

Measurement of thermoluminescence - a new method for detecting radiation treatment of spices  

International Nuclear Information System (INIS)

By the experiments described in this report it was examined in 14 different spices to which extent measurements of thermoluminescence intensity of up to 3000C are suitable for detecting treatment with ionizing radiation. The optimal weight of each spice was first determined for a later investigation of the dependence of thermoluminescence intensity on dose and postirradiation storage. In most spices, radiation treatment is detectable as long as after a storage period of over 2 months. In general it may be stated that thermoluminescence measurement is a reliable method for detecting radiation treatment in supplement to chemiluminescence measurement. (orig./PW)

8

A Testing Method on Detection Threshold for Channel Vehicle Radiation Monitoring System to ? Radionuclide Activity  

International Nuclear Information System (INIS)

A testing method on detection threshold for channel vehicle radiation monitoring system to ? radionuclide activity was discussed. The detection threshold to certain radionuelide indicates the minimum detectable activity, which characterizes the detection ability of system as well as is the foundation for system alarm setting. The detection threshold can be obtained by calculating the statistical fluctuation of the background of detector and the measuring results to activity response of reference point, for a certain reference point, detection threshold is related to the statistical fluctuation of the background and ?-energy spectrum. (authors)

9

FISH as a method for detection of radiation Induced genetic damage  

International Nuclear Information System (INIS)

Fluorescence in situ hybridisation (FISH) has been considered as a suitable method for the rapid and easy detection of chromosome aberrations. In contrast to the standard conventional staining procedure, this technique enables the specification of stable chromosomal re-arrangements, which 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. (authors)

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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

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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 of detection of transition radiation by wire chambers operating in self-quenching streamer mode  

International Nuclear Information System (INIS)

A method for detecting X-ray transition radiation against the background of the signal from relativistic charged particles is suggested that is based on the use of peculiarities of the development of self-queenching streamer mode. The self-qunching streamer discharge in the Xe+ isobutane mixture is experimentally registered. The effect of separation of signals from the relativistic particle and from soft X-ray, is obtained

14

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)

15

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)

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Methods for radiation detection and characterization using a multiple detector probe  

Science.gov (United States)

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

17

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

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Heterodyne detection of synchrotron radiation  

Energy Technology Data Exchange (ETDEWEB)

A time integral method for the study of resonant nuclear scattering of synchrotron radiation in the forward direction is presented. The method relies on the interference of radiation scattered by nuclei in two samples, one moving with respect to the other. The method, termed heterodyne detection of synchrotron radiation, gives the same information on hyperfine parameters as the well known differential method. The general formalism is developed for the case where the reference is a single line sample and the investigated sample has magnetic or quadrupole splitting. The first experiments are discussed. A comparison of time differential synchrotron radiation spectroscopy, heterodyne detection and Moessbauer spectroscopy is given.

Coussement, R.; Odeurs, J.; L' abbe, C.; Neyens, G

2000-03-15

19

Electron detection using synchrotron radiation  

International Nuclear Information System (INIS)

The author presents calculations for the detection of photons from synchrotron radiation, and discusses how it can be incorporated into existing electron detection schemes. The detection of electrons by synchrotron radiation has been proposed and used by S. Aronson and L. Pondrom, and preliminary calculations on this method have been presented by S. Aronson. In this paper, the author considers in more detail the method of using the synchrotron radiation emitted by accelerated electrons in magnetic fields in a practical detector. One scheme would utilize the detection of the photons in a gas of Xe, much in the same way as photons from transition radiation are detected. In fact the energy of the detected gamma rays are very close for the two methods and thus it is expected that we could make use of in fact the identical detectors

20

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

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Semiconductor radiation detection systems  

CERN Document Server

Covers research in semiconductor detector and integrated circuit design in the context of medical imaging using ionizing radiation. This book explores other applications of semiconductor radiation detection systems in security applications such as luggage scanning, dirty bomb detection and border control.

2010-01-01

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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)

23

Detection of defects on weld radiographs using a modified radiation projection method  

Science.gov (United States)

This article discussed the computerized automatic evaluation of weld radiographs. The radiation projection method (RPM) was introduced, and a modified calculation method based on RPM was proposed. The actual experimental results demonstrated that this new method improved the ability of RPM to suppress the interference of noise.

Gao, Jun; Pan, Menxian; Yang, Xuezhi; Wang, Xu F.

1998-09-01

24

Radiation interaction and detection principles  

International Nuclear Information System (INIS)

Part I of this presentation describes the interactions of different types of ionizing radiation with matter and the principal physical processes for energy loss. Part II discusses these phenomena as the basis for various methods of detecting and measuring ionizing radiation

25

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.)

26

Development of detection · analytical techniques applied with new DNA analytical methods for radiation mutation. Improvement of detection efficiency, development of effective probe and primer and detection techniques  

International Nuclear Information System (INIS)

Evaluation of the degree of gene defects in a special region was made using culture cell lines and long PCR method was found usable. A genome size in a length around 30 kb or more was detectable and an insertion of about 5 kb was also detectable. Based on these results, several model genes; (1) long repeated sequences dispersed in a genome, (2) gene group consisting a large cluster and (3) single gene were chosen to detect by PCR amplification. In this fiscal year, the sequence which constructs chromosome end was isolated as a marker sequence and the effects of radiation on the sequence were investigated. Its amplification hardly occurred at 0.5 Gy and started at a range, 1-10 Gy. The peak effects were observed at ?4 Gy. These results suggest that these sequences have high-ordered conformations till radiation exposure produces a cleavage in the sequence, so that its amplification by PCR method would not occur without any structural change. (M.N.)

27

A method to detect ultra high energy electrons using earth's magnetic field as a radiator  

Science.gov (United States)

It is pointed out that the detection of electrons with energies exceeding a few TeV, which lose energy rapidly through synchrotron and inverse Compton processes, would provide valuable information on the distribution of sources and on the propagation of cosmic rays in the solar neighborhood. However, it would not be possible to measure the energy spectrum beyond a few TeV with any of the existing experimental techniques. The present investigation is, therefore concerned with the possibility of detecting electrons with energies exceeding a few TeV on the basis of the photons emitted through synchrotron radiation in the earth's magnetic field. Attention is given to the synchrotron radiation of electrons in the earth's magnetic field, detector response and energy estimation, and the characteristics of an ideal detector, capable of detecting photons with energies equal to or greater than 20 keV.

Stephens, S. A.; Balasubrahmanyan, V. K.

1983-01-01

28

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)

29

Method for the detection and localisation of radiation and an arrangement for the application of this method  

International Nuclear Information System (INIS)

Procedure for the detection and localisation of neutral radiation, particularly soft gamma or X-radiation, whereby photoelectrons will be formed, so that the incident radiation influences gas atoms which are contained in a gas vessel; with the assistance of an electric field the electrons in the field space may be deflected by a movement depending on the electric field, the strength of which is sufficient for secondary photons to promote (by excitation of the gas atoms) the excited state of these atoms, and the place at which the secondary photons may be determined, characterised in that simultaneously a selected value of the energy of the secondary photons may be found. (G.C.)

30

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

31

Data derandomizer and method of operation for radiation imaging detection systems  

International Nuclear Information System (INIS)

A radiation imaging detection system, such as a scintillation camera system, including analog data derandomizing circuitry for reducing otherwise occurring data losses is described. The derandomizing circuitry includes a peak detector, a ratio circuit, and a sample and hold circuit in combination such that a randomly occurring data pulse stored in the peak detector is transferred to the sample and hold circuit only if it is not busy. The sample and hold circuit maintains the data for a sufficient time to enable display. If the sample and hold circuit is busy and cannot accept new data for display, the peak detector stores the data pulse. The derandomizer detects only a middle portion of an incoming data pulse to determine its peak to thereby realize a timing advantage. The novel peak detector herein disclosed provides an input voltage pedestal to the input pulses for enhancing detection, and provides a dumping circuit to rapidly discharge the holding capacity at a rate proportional to the detector output voltage

32

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

International Nuclear Information System (INIS)

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. 6 figs

33

Development of techniques using DNA analysis method for detection/analysis of radiation-induced mutation. Development of an useful probe/primer and improvement of detection efficacy  

International Nuclear Information System (INIS)

Previously, it was demonstrated that detection of centromere became easy and reliable through fluorescent staining by FISH method using a probe of the sequence preserved in ?-satelite DNA. Since it was, however, found inappropriate to detect dicentrics based on the relative amount of DNA probe on each chromosome. A prove which allows homogeneous detection of ?-satelite DNA for each chromosome was constructed. A presumed sequence specific to kinetochore, CENP-B box was amplified by PCR method and the product DNA was used as a probe. However, the variation in amounts of probe DNA among chromosomes was decreased by only about 20%. Then, a program for image processing of the results obtained from FISH using ?-satelite DNA was constructed to use as a marker for centromere. When compared with detection of abnormal chromosomes stained by the conventional method, calculation efficacy for only detection of centromere was improved by the use of this program. Calculation to discriminate the normal or not was still complicated and the detection efficacy was little improved. Chromosomal abnormalities in lymphocytes were used to detect the effects of radiation. In this method, it is needed to shift the phase of cells into metaphase. The mutation induced by radiation might be often repaired during shifting. To exclude this possibility, DNA extraction was conducted at a low temperature and immediately after exposure to 137Cs, and a rapid genome detection method was esta rapid genome detection method was established using the genome DNA. As the model genomes, the following three were used: 1) long chain repeated sequences widely dispersed over chromosome, 2) cluster genes, 3) single copy genes. The effects of radiation were detectable at 1-2 Gy for the long repeated sequences and at 7 Gy for the cluster genes, respectively, whereas no significant effects were observed at any Gy tested for the single copy genes. Amplification was marked in the cells exposed at 1-10 Gy (peak at 4 Gy), suggesting that these regions had very highly ordered structures. (M.N.)

34

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)

35

Photostimulated luminescence of corrugated fiberboard as an additional screening method for detecting radiated foods  

International Nuclear Information System (INIS)

In this study, PSL of non-irradiated and irradiated corrugated fiberboards (CFs) was investigated to evaluate the possibility that CFs can be used as alternative specimens for the screening detection method of food irradiation. The irradiation at a dose of only 0.15 kGy increased PSL signals of the CF over 1 order of magnitude. The PSL signals increased with increasing in gamma irradiation dose and became almost saturated at a dose of 5 kGy. The core of CFs showed PSL signals sufficient for distinguishing irradiated from non-irradiated at least 6 months after irradiation even though the CF was exposed to light and the environmental temperature increased to 50 °C. These results suggest that the PSL property of the core of CFs is useful for detecting irradiation. However, the large variation of PSL signals among CFs made it difficult to set a well-defined “positive” threshold limit to distinguish irradiated from non-irradiated completely. All of the non-irradiated CFs showed PSL signals above 103 counts, which is much higher than that detected for foods. It is apparent that the threshold limit of EN 13751 is not applicable to detecting irradiated CFs. More detailed collaborative research with large number of samples is needed to establish new threshold limits involving “intermediate” classification. - Highlights: ? Corrugated fiberboards (CF) as a packaging material were gamma-irradiated. ? The photostimulated luminescence (PSL) signals of irradicence (PSL) signals of irradiated CF were measured. ? The PSL signals were sufficient for detecting irradiation. ? The signals were well retained for 6 months after irradiation upon exposure to light. ? The environmental temperature at 50 °C had little effects on the signal retention.

36

Radiation detection device  

International Nuclear Information System (INIS)

A radiation detection device is claimed. The ionization chamber detector in the housing comprises: a high voltage electrode which is directed transverse to the entrance window; a collector electrode parallel to the high voltage electrode and spaced such that radiation entering the housing through the entrance window passes between the electrodes; an ionizible gas between the electrodes; a high voltage source having two output terminals, one electrically connected to the high voltage electrode; current measuring means having two terminals, one electrically connected to the other output terminal of the high voltage source, and the second electrically connected to the collector electrode; a flat auxiliary electrode adjacent and parallel to the entrance window and having a relatively high electrical resistance measured in the direction transverse to the collector electrode. This auxiliary electrode has one end adjacent the high voltage electrode and the other adjacent but not directly electrically connected to the collector electrode. The output terminals of the high voltage source are electrically connected to the ends of the auxiliary electrode such that the electric field between the high voltage and collector electrodes is substantially homogeneous in the vicinity of the auxiliary electrode

37

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

38

Data derandomizer and method of operation for radiation imaging detection systems  

International Nuclear Information System (INIS)

The present invention provides a new and improved analog nuclear radiation imaging system which has an analog signal processor that derandomizes the analog data. Digitalization of the analog data pulses is not required, and by employing a novel peak detector circuit, an overall faster operation, more reponsive system is provided. The signal processing circuitry accomodates dual isotope applications and is adapted to operate under internally generated control conditions or under externally generated control conditions. (auth)

39

Detection methods for irradiated food  

International Nuclear Information System (INIS)

The plenary lecture gives a brief historical review of the development of methods for the detection of food irradiation and defines the demands on such methods. The methods described in detail are as follows: 1) Physical methods: As examples of luminescence methods, thermoluminescence and chermoluminescence are mentioned; ESR spectroscopy is discussed in detail by means of individual examples (crustaceans, frutis and vegetables, spieces and herbs, nuts). 2) Chemical methods: Examples given for these are methods that make use of alterations in lipids through radiation (formation of long-chain hydrocarbons, formation of 2-alkyl butanones), respectively radiation-induced alterations in the DNA. 3) Microbiological methods. An extensive bibliography is appended. (VHE)

40

Integration of Electrical Resistivity and Electromagnetic Radiation Methods for Fracture Flow System Detection  

OpenAIRE

An electrical resistivity and electromagnetic emission survey was carried out involving the use of vertical electrical soundings (VES) and natural pulse electromagnetic field of the earth (NPEMFE). The use of this new methodology managed to detect the fracture flow system rupture zones in the underground, also answered the questions about the deferent subsurface water bodies. The present study focuses on Marsaba-Feshcha sub-basin in the northeast of the Dead Sea. Due...

Jawad Hasan Shoqeir; Heinz Hoetzl; Akiva Flexer

2014-01-01

41

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

42

Main Achievements 2003-2004 - Interdisciplinary Research - Radiation detection methods for health, earth and environmental sciences - Detection methods in gas chromatography  

International Nuclear Information System (INIS)

Detection methods in gas chromatography are under development, especially ultra-sensitive gas chromatography detection methods to monitor the atmosphere (with respect to gases active in the destruction of the Earth ozone layer). A new chromatographic method has been elaborated for Ne determination, and technique for determination of Ar and N2 in groundwater has been significantly improved. Measurements of neon are performed by means of a chromatographic system equipped with a helium ionization detector (PD-HID) doped with neon pulse discharge, working with a modified sample introduction system. The Ar and N2 contents are determined by a thermal-conductivity detector (TCD). The problem of separation of Ar from O2 has been solved by catalytic removal of the latter from the sample. The measurement reproducibility is 1%, 2% and 0.5% for Ar, Ne and N2, respectively. Both methods were successfully applied in measurements of groundwaters in the Cracow area. The excess air contents are in the range of about 1 to 3 cm3 STP L-1. The values of recharge temperatures for Holocen water agree reasonably well with the yearly mean long-term surface air temperature (8.2 oC)

43

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

44

Detecting radiation reaction at moderate laser intensities  

Science.gov (United States)

We propose a new method of detecting radiation reaction effects in the motion of particles subjected to laser pulses of moderate intensity and long duration. The effect becomes sizable for particles that gain almost no energy through the interaction with the laser pulse. Hence, there are regions of parameter space in which radiation reaction is actually the dominant influence on charged particle motion.

Heinzl, Thomas; Harvey, Chris; Ilderton, Anton; Marklund, Mattias; Bulanov, Stepan S.; Rykovanov, Sergey; Schroeder, Carl B.; Esarey, Eric; Leemans, Wim P.

2015-02-01

45

Methods for routine control of irradiated food: optimization of a method for detection of radiation-induced hydrocarbons and its application to various foods  

International Nuclear Information System (INIS)

By comparison of two methods for the isolation of radiation-induced hydrocarbons, high vacuum ''cold finger'' distillation and Florisil column chromatography, it could be shown that the sensitivity of both was similar whereas the latter seemed to be more practical for routine application. In optimizing studies, the influence of the degree of Florisil activation and the influence of the irradiation temperature on hydrocarbon yields as the resolution of hydrocarbons on polar and non-polar gas chromatographic capillary columns have been examined. From the successful application of the method to different fat containing foodstuffs, it is concluded that the Florisil column chromatography is well suited as clean-up procedure for the gas chromatographic/mass spectrometric (GC/MS) detection of irradiated products by routine food control analyses. (author)

46

Labor security in radiation flaw detection  

International Nuclear Information System (INIS)

Problems of ensuring safe labour conditions in radiation flaw detection are considered. Methods for ionizing radiation protection are given calculating techniques for shielding flaw detectors and stationary structures are presented as well. Safe methods of nondestructive testing of items under field conditions, in a shop and special laboratories using gamma- and X-ray flaw detectors, betatrons, electron accelerators are described. Attention is paid to the principles of radiation factor stantardization as well as radiation monitoring. Analysis of accidents and recommendations on their prevention and liquidation of accidental consequences are given

47

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

48

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

49

Environmental radiation and detection  

International Nuclear Information System (INIS)

Environmental radiation permeates space, air, soil and water around us. It has been naturally present since the birth of earth about 4.65 billion years ago in a massive supernova explosion creating the heavy elements on earth and the other rocky planets Mars, Venus and Mercury. Consequently, life has evolved in the ashes and remnants of this explosion which are gravitationally grabbed in space by the sun into our solar system in an environment which has significant levels of ionizing radiation. Any untoward happening in the peaceful application of radioisotopes in industry, nuclear power production, medical field, agriculture use satellite crash or in transportation of radioactive materials in India may affect concerned occupational workers and limited population. We are constantly exposed to small amounts of radiation from the environment as we carry out our normal daily activities. Environmental radiation comes from the sky, the earth, and the air we breathe and can be categorized as natural or artificial. (author)

50

A radiation remote detection device  

International Nuclear Information System (INIS)

The radiation detection device is composed of an optical fiber, a sensing crystal, which, when interacting with a radiation, emits light that propagates through the fiber optic, and an optic sheath surrounding the crystal. The sheath refractive index is inferior to the crystal index, thus ensuring that the light is totally confined. Application to dosimetry and microdosimetry. 3 refs., 2 figs

51

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

52

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

53

Detection of gravitational radiation  

International Nuclear Information System (INIS)

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)

54

Sensor and method for measurment of select components of a material based on detection of radiation after interaction with the material  

International Nuclear Information System (INIS)

A sensor is described for measuring one or more select components of a sheet, comprising: a radiation source for emitting radiation toward the sheet; a plurality of detecting means, wherein at least one detecting means is offset from the source, for detecting radiation after interaction with the sheet; means for directing the radiation so that the radiation makes multiple interactions with the sheet in moving from the source to the detecting means, wherein the directing means includes a first reflector and second reflector defining a sheet space for the sheet to occupy; means for computing a ratio of the intensity of the detected radiation when the sheet is absent from the sheet space and the intensity of the detected radiation when the sheet occupies the sheet space; and means for computing the absorption power of the sheet from the intensity of the detected radiation

55

Development of detection {center_dot} analytical techniques applied with new DNA analytical methods for radiation mutation. Improvement of detection efficiency, development of effective probe and primer and detection techniques  

Energy Technology Data Exchange (ETDEWEB)

Evaluation of the degree of gene defects in a special region was made using culture cell lines and long PCR method was found usable. A genome size in a length around 30 kb or more was detectable and an insertion of about 5 kb was also detectable. Based on these results, several model genes; (1) long repeated sequences dispersed in a genome, (2) gene group consisting a large cluster and (3) single gene were chosen to detect by PCR amplification. In this fiscal year, the sequence which constructs chromosome end was isolated as a marker sequence and the effects of radiation on the sequence were investigated. Its amplification hardly occurred at 0.5 Gy and started at a range, 1-10 Gy. The peak effects were observed at {approx}4 Gy. These results suggest that these sequences have high-ordered conformations till radiation exposure produces a cleavage in the sequence, so that its amplification by PCR method would not occur without any structural change. (M.N.)

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

1998-02-01

56

A method for detection of hydroxyl radicals in the vicinity of biomolecules using radiation-induced fluorescence of coumarin  

Energy Technology Data Exchange (ETDEWEB)

A novel method is described to quantitate radiation-induced hydroxyl radicals in the vicinity of biomolecules in aqueous solutions. Coumarin-3-carboxylic acid (CCA) is a non-fluorescent molecule that, upon interaction with radiation in aqueous solution, produces fluorescent products. CCA was derivatized to its succinimidyl ester (SECCA) and coupled to free primary amines of albumin, avidin, histone-H1, polylysine, and an oligonucleotide. When SECCA-biomolecule conjugates were irradiated, the relationship between induced fluorescence and dose was linear in the dose range examined (0.01-10 Gy). The data indicate that the induction of fluorescence on SECCA-biomolecule conjugates records specifically the presence of the hydroxyl radical in the immediate vicinity of the irradiated biomolecule. The method is rapid and sensitive, uses standard instrumentation, and the sample remains available for further studies. (Author).

Makrigiorgos, G.M.; Baranowska-Kortylewicz, J.; Bump, E.; Sahu, S.K.; Berman, R.M.; Kassis, A.I. (Harvard Medical School, Boston, MA (United States))

1993-04-01

57

A method for detection of hydroxyl radicals in the vicinity of biomolecules using radiation-induced fluorescence of coumarin  

International Nuclear Information System (INIS)

A novel method is described to quantitate radiation-induced hydroxyl radicals in the vicinity of biomolecules in aqueous solutions. Coumarin-3-carboxylic acid (CCA) is a non-fluorescent molecule that, upon interaction with radiation in aqueous solution, produces fluorescent products. CCA was derivatized to its succinimidyl ester (SECCA) and coupled to free primary amines of albumin, avidin, histone-H1, polylysine, and an oligonucleotide. When SECCA-biomolecule conjugates were irradiated, the relationship between induced fluorescence and dose was linear in the dose range examined (0.01-10 Gy). The data indicate that the induction of fluorescence on SECCA-biomolecule conjugates records specifically the presence of the hydroxyl radical in the immediate vicinity of the irradiated biomolecule. The method is rapid and sensitive, uses standard instrumentation, and the sample remains available for further studies. (Author)

58

Non-ionizing radiation detection  

International Nuclear Information System (INIS)

sensors network for non-ionizing radiation detection in the band of 800 MHz to 2.5 GHz was designed and constructed. The system is based on a sensor which shows an output DC voltage proportional to the input RF signal. This network is made of four broad band antennas, four circuit board sensors, a main board and data visualization software. The performance system was analyzed changing its configuration and using several radiation sources. The results presented include the simulation of an Archimedes antenna using CST STUDIOTM and the experimental results of a broad band HG2404CU antenna. The results have shown an efficient system for the electromagnetic radiation detection. As a second part of this work, this prototype will be used as a detector of cellular phone calls in places where they are not allowed such as prisons, banks and so on.

59

Detecting radiation reaction at moderate laser intensities  

CERN Document Server

We propose a new method of detecting radiation reaction effects in the motion of particles subjected to laser pulses of moderate intensity and long duration. The effect becomes sizeable for particles that gain almost no energy through the interaction with the laser pulse.

Heinzl, Thomas; Ilderton, Anton; Marklund, Mattias; Bulanov, Stepan S; Rykovanov, Sergey; Schroeder, Carl B; Esarey, Eric; Leemans, Wim P

2013-01-01

60

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

61

Radiation Detection for Active Interrogation of HEU  

International Nuclear Information System (INIS)

This report briefly describes the neutrons and gamma rays emitted by active interrogation of HEU, briefly discusses measurement methods, briefly discusses sources and detectors relevant to detection of shielded HEU in Sealand containers, and lists the measurement possibilities for the various sources. All but one of the measurement methods detect radiation emitted by induced fission in the HEU; the exception utilizes nuclear resonance fluorescence. The brief descriptions are supplemented by references. This report presents some active interrogation possibilities but the status of understanding is not advanced enough to select particular methods. Additional research is needed to evaluate these possibilities

62

Post-factum detection of radiation treatment in processed food by analysis of radiation-induced hydrocarbons. Pt. 1. Applying the method L 06.00-37 defined in Para. 35 LMBG (German Act on Food Irradiation) to processed food  

International Nuclear Information System (INIS)

The German official method L 06.00-37 (Para. 35 German Act on Food Irradiation) is used for the identification of irradiated fat-containing food by GC-analysis of radiation-induced hydrocarbons. Simple modifications in sample preparation allow a distinctive improvement in detection possibilities and detection limits as well. The applicability of the modified method for the detection of irradiated ingredients in model-like processed food is shown. An identification of only 3% (irradiated fat to total fat ratio) irradiated ingredient (1,5 kGy) in processed food was possible. Additionally, the kind of irradiated ingredient could be identified by the pattern of radiation induced hydrocarbons. Their concentrations are corresponding with the fatty acid composition of the irradiated compound. (orig.)

63

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)

64

Remote Optical Detection of Alpha Radiation  

International Nuclear Information System (INIS)

Alpha emitting radiation sources are typically hard to detect with conventional detectors due to the short range of alpha particles in the air. However, previous studies have shown that remote detection of alpha radiation is possible by measuring the ionization-induced fluorescence of air molecules. The alpha-induced ultraviolet (UV) light is mainly emitted by molecular nitrogen and its fluorescence properties are well known. The benefit of this method is the long range of UV photons in the air. Secondly, the detection is possible also under a strong beta and gamma radiation backgrounds as they do not cause localized molecular excitation. In this work, the optical detection was studied using two different detection schemes; spectral separation of fluorescence from the background lighting and coincidence detection of UV photons originating from a single radiative decay event. Our spectrally integrated measurements have shown that one alpha decay event yields up to 400 fluorescence photons in the air and all these UV photons are induced in a 5 ns time-window. On the other hand, the probability of a background coincidence event in 5 ns scale is very rare compared to the number of background photons. This information can be applied in fluorescence coincidence filtering to discriminate the alpha radiation initiated fluorescence signal from much more intense background lighting. A device called HAUVA (Handheld Alpha UV Application) was built during this work for demonstration purposes. HAUVA utilizes spectral filtering and it is designed to detect alpha emitters from a distance of about 40 cm. Using specially selected room lighting, the device is able to separate 1 kBq alpha emitter from the background lighting with 1 second integration time. (author)

65

Detecting biological effects of ionising radiation  

International Nuclear Information System (INIS)

This work discussed the following topics: Radiation damage and time. Short and Long term effects. Ionising radiation affect all cellular components. DNA main target for ionising radiation. Direct, Indirect and Bystander effect of radiation. Biological effect. Influence of different factors (Physical factors and Biological factors). Cellular repair of DNA damage. Cells with different repair capability. Cellular death detection. Chromosome aberration detection

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

Means and methods used to check radiation detection, signalling and alarm devices in the centralized environment control systems of the INB of CEN-Saclay  

International Nuclear Information System (INIS)

Having reviewed the prescribed technical measures concerning 'systematic environment controls' in INB (Installations nucleaires de base - basic nuclear facilities) and published in the J.O. (French Official Journal) the authors briefly describe the main radiation detection, signalling and alarm systems at present installed in INB of CEN-Saclay and weigh up the extent to which their characteristics comply with the statutory texts. They then develop the means and methods set up to check on the good working order of these devices which are integrated in centralised one-piece modular analogue or informatics type control systems possible functioning anomalies being classed in two categories: logic type anomalies corresonding to a straightforward breakdown where detection is permanent; developing anomalies corresponding to poor functioning where detection requires a more critical and periodic control. The authors demonstrate the advantages offered by centralised computer type control systems

68

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.

69

Exoplanet Detection Methods  

CERN Document Server

This chapter reviews various methods of detecting planetary companions to stars from an observational perspective, focusing on radial velocities, astrometry, direct imaging, transits, and gravitational microlensing. For each method, this chapter first derives or summarizes the basic observable phenomena that are used to infer the ex- istence of planetary companions, as well as the physical properties of the planets and host stars that can be derived from the measurement of these signals. This chapter then outlines the general experimental requirements to robustly detect the signals us- ing each method, by comparing their magnitude to the typical sources of measurement uncertainty. This chapter goes on to compare the various methods to each other by outlining the regions of planet and host star parameter space where each method is most sensitive, stressing the complementarity of the ensemble of the methods at our disposal. Finally, there is a brief review of the history of the young exoplanet field, from the f...

Wright, Jason T

2012-01-01

70

Ionizing radiations, detection, dosimetry, spectrometry  

International Nuclear Information System (INIS)

A few works in French language are devoted to the detection of radiations. The purpose of this book is to fill a gap.The five first chapters are devoted to the properties of ionizing radiations (x rays, gamma rays, leptons, hadrons, nuclei) and to their interactions with matter. The way of classification of detectors is delicate and is studied in the chapter six. In the chapter seven are studied the statistics laws for counting and the spectrometry of particles is treated. The chapters eight to thirteen study the problems of ionization: charges transport in a gas, ionization chambers (theory of Boag), counters and proportional chambers, counters with 'streamers', chambers with derive, spark detectors, ionization chambers in liquid medium, Geiger-Mueller counters. The use of a luminous signal is the object of the chapters 14 to 16: conversion of a luminous signal in an electric signal, scintillators, use of the Cerenkov radiation. Then, we find the neutron detection with the chapter seventeen and the dosimetry of particles in the chapter eighteen. This book does not pretend to answer to specialists questions but can be useful to physicians, engineers or physics teachers. (N.C.)

71

Practical application of narrow area radiation method  

International Nuclear Information System (INIS)

This paper describes the estimation of attainable quality on X-ray radiographs and an application of narrow area radiation method. Results are obtained as follows; 1) The fundamental data of factors governing quality on radiographs were collected and were arranged as empirical equations. Then the detectability of I.Q.I. wires and blow-holes were calculated numerically. The calculated values almost agreed with the experimental values within practical limits of error. 2) The optimum object-film distance in the narrow area radiation method was calculated under minimization of the detectability of I.Q.I. wires. 3) The narrow area radiation method was applied to the welds for corner joints of truss-chord members. The detectability of blow-holes with this method was better than that using ordinary methods. (author)

72

Fluorometric method for rapid detection of DNA strand breaks in human white blood cells produced by low doses of radiation  

International Nuclear Information System (INIS)

DNA strand breaks can be detected with great sensitivity by exposing crude cell lysates to alkaline solutions and monitoring the rate of strand unwinding. As little as one strand break per chromosome can be detected. Previous methods for measuring strand unwinding have required physical separation of single- from double-stranded molecules. We now describe conditions under which unwinding can be monitored directly using a fluorescent dye, thus greatly simplifying the analysis. Breaks due to irradiation of blood samples by 60Co gamma-rays at doses as low as 0.05 to 0.1 gray (5 to 10 rads) were detectable. Rapid rejoining of strand breaks during in vitro incubation at 37 degrees could readily be observed following a dose of one gray. Since the procedure is very rapid and cells can be analyzed directly without the requirement for culturing or radiolabeling, the procedure could be useful in cancer chemotherapy if in vivo damage is to be monitored or for testing the in vitro sensitivity of cells to drugs

73

Fluorometric method for rapid detection of DNA strand breaks in human white blood cells produced by low doses of radiation  

International Nuclear Information System (INIS)

DNA strand breaks can be detected with great sensitivity by exposing crude cell lysates to alkaline solutions and monitoring the rate of strand unwinding. As little as one strand break per chromosome can be detected. Previous methods for measuring strand unwinding have required physical separation of single- from double-stranded molecules. Researchers now describe conditions under which unwinding can be monitored directly using a fluorescent dye, thus greatly simplifying the analysis. Breaks due to irradiation of blood samples by 60Co gamma-rays at doses as low as 0.05 to 0.1 gray were detectable. Rapid rejoining of strand breaks during in vitro incubation at 37 degrees could readily be observed following a dose of one gray. Since the procedure is very rapid and cells can be analyzed directly without the requirement for culturing or radiolabeling, the procedure could be useful in cancer chemotherapy if in vivo damage is to be monitored or for testing the in vitro sensitivity of cells to drugs

74

Radiation delivery system and method  

Science.gov (United States)

A radiation delivery system and method are described. The system includes a treatment configuration such as a stent, balloon catheter, wire, ribbon, or the like, a portion of which is covered with a gold layer. Chemisorbed to the gold layer is a radiation-emitting self-assembled monolayer or a radiation-emitting polymer. The radiation delivery system is compatible with medical catheter-based technologies to provide a therapeutic dose of radiation to a lesion following an angioplasty procedure.

Sorensen, Scott A. (Overland Park, KS); Robison, Thomas W. (Los Alamos, NM); Taylor, Craig M. V. (Jemez Springs, NM)

2002-01-01

75

Detecting radiation with your smartphone  

CERN Document Server

The winners of the CERN EIROforum Prize in the European Union Competition for Young Scientists 2013 (EUCYS), Micha? Gumiela and Rafa? Tomasz Kozik from Poland, have just spent an exciting week exploring CERN from 1 to 5 September. The students visited several CERN experiments and facilities and had ample time to interact with scientists on how to improve their invention further.   Micha? Gumiela (left) and Rafa? Tomasz Kozik (right) with their CERN host, Sabrina El Yacoubi (middle) at the ALICE detector. Micha? (21) and Rafa? (20) both won a young physicist prize in Poland before submitting their work on “Studies of the applicability of CMOS and CCD sensors for detection of ionising radiation” to the EUCYS competition. “It all started with Fukushima,” recalls Micha?. The high school students met in 2011 at a physics workshop, where they started discussing digital photos taken around the Fukushima nuclear plant after the radiation leak. &ldqu...

Agnes Szeberenyi

2014-01-01

76

Radiation detection at submillimetre wavelengths  

International Nuclear Information System (INIS)

Techniques and devices for the detection and sensing of radiation in the wavelength range from about 1 mm to 2 ?m are reviewed. Most attention is given to the developments of the past few years, but an attempt is also made to cover the field comprehensively. Brief accounts are given of the characterisation of detection devices, and the general properties of receiver systems, particularly those of the video and heterodyne types. The performance of practical detector devices is then reviewed, most falling into the broad groups of thermal (including 3He and 4He-cooled bolometers), rectifying or photoconductive types. Brief descriptions are given of imaging devices and the present status of heterodyne systems. A steady improvement in the performance of both the newer and the well established devices is reported, but the author points out the need for more accurate calibration of detector performance so that more useful comparisons may be made. (author)

77

Hot point detection method  

International Nuclear Information System (INIS)

Highlights: ? A method is derived exploiting SPND detector information for hot spot identification. ? The method uses sensitivity coefficients by GPT method to obtain hot point estimates. ? The effect of a detection device system degradation may be taken into account. - Abstract: A method is described by which the information obtained on-line through a system of neutron measuring devices such as self-powered neutron detectors (SPNDs, also called collectrons) inserted in the core of a nuclear power reactor (in particular, a PWR) allows the on-line detection of a possible hot spot during plant operation. The method is based on the generalized perturbation method (GPT) techniques, for the calculation of the sensitivity coefficients of the integral quantities measured with the collectrons with respect to parameters representative of the hot spot, and on the use of statistical inference techniques, taking into account the errors associated with the measurements. The methodology allows to assess the effect on the quality of the hot point detection system following possible failures of the measuring devices during the core life cycle. Such an assessment may be useful for defining an adequate protection strategy in terms of quality, number and distribution of the collectrons.

78

A study on measurement of neutrons generated in radiation therapy – Measurement of neurons in CR-39 detection method  

International Nuclear Information System (INIS)

Highlights: ? To measure the neutrons generated in a linear accelerator. ? Both fast neutrons and thermal neutrons produced an increase in the dose of neutrons generated with increasing irradiation dose. ? The generation of neutrons increased when a wedge filter was used. ? When the SRS cone that required a high dose was used, more neutrons were detected. -- Abstract: The CR-39 [diethylene glycol bis-(allylcarbonate)] neuron detection method was used to measure the dose of neutrons generated in X-ray (photon) therapy conducted in a linear accelerator, and to use high-energy photons as part of the clinical applications to examine the problems associated with the dose for patients caused by the generation of neutrons from high-energy photons used for cancer therapy. According to the experimental results, 0.35 mSv, 0.65 mSv 1.82 mSv of fast neutrons on average were generated from 1 Gy, 2 Gy and 5 Gy of photon irradiation, respectively, whereas 0.26 mSv, 0.56 mSv and 1.23 mSv of thermal neutrons were generated. Both fast neutrons and thermal neutrons produced an increase in the dose of neutrons generated with increasing irradiation dose. With in regard to the dose generated within and around the irradiation area of the photon rays, it was confirmed that more neutrons were generated within the irradiation area. A wedge filer was used to measure the generation of neutrons. According to the measurement results, the generation of neutrons increased when a wedge filterrons increased when a wedge filter was used. When the SRS cone that required a high dose was used, more neutrons were detected than those in the previous experiment. When fast neutrons were used, 2.85 mSv neutrons on average were generated from 5 Gy of photon irradiation. When thermal neutrons were used, 1.37 mSv neutrons on average were generated from 5 Gy of photon irradiation. Overall, approximately 1.6 times and 1.12 times more fast and thermal neutrons, respectively, were generated than in the case of a general treatment with 5 Gy of photon irradiation.

79

Radiation-induced defects method  

International Nuclear Information System (INIS)

A radiation-induced defect method recommended for application to prospecting for and forecasting of uranium deposits for estimation of radiogeochemical anomalies, tracing migration ways of ore-bearing solution and clarification of uranium mineralization age is described. The method is based on determination of ionizing radiation dose absorbed by rocks. Ionizing radiation of natural radioelements gives rise to electron-hole centres in the crystal structure; these centres are associated with point radiation defects, the concentration of which depends on radiation intensity and duration and it is determined using the electron spin resonance method. Quartz is the most effective mineral-dosimeter. Results of horizontal paleodosimetric mapping for studying conditions for formation of stratiform uranium mineralization are considered as an example of using the radiation-induced defect method

80

Three-dimensional, position-sensitive radiation detection  

Science.gov (United States)

Disclosed herein is a method of determining a characteristic of radiation detected by a radiation detector via a multiple-pixel event having a plurality of radiation interactions. The method includes determining a cathode-to-anode signal ratio for a selected interaction of the plurality of radiation interactions based on electron drift time data for the selected interaction, and determining the radiation characteristic for the multiple-pixel event based on both the cathode-to-anode signal ratio and the electron drift time data. In some embodiments, the method further includes determining a correction factor for the radiation characteristic based on an interaction depth of the plurality of radiation interactions, a lateral distance between the selected interaction and a further interaction of the plurality of radiation interactions, and the lateral positioning of the plurality of radiation interactions.

He, Zhong; Zhang, Feng

2010-04-06

81

Physics and engineering of radiation detection  

CERN Document Server

Physics and Engineering of Radiation Detection presents an overview of the physics of radiation detection and its applications. It 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. The second edition is fully revised and provides the latest developments in detector technology and analyses software. Also, more material related to measurements in particle physics and a complete solutions manual have been added.

Ahmed, Syed Naeem

2015-01-01

82

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)

83

Network Algorithms for Detection of Radiation Sources  

Energy Technology Data Exchange (ETDEWEB)

In support of national defense, Domestic Nuclear Detection Office s (DNDO) Intelligent Radiation Sensor Systems (IRSS) program supported the development of networks of radiation counters for detecting, localizing and identifying low-level, hazardous radiation sources. Industry teams developed the first generation of such networks with tens of counters, and demonstrated several of their capabilities in indoor and outdoor characterization tests. Subsequently, these test measurements have been used in algorithm replays using various sub-networks of counters. Test measurements combined with algorithm outputs are used to extract Key Measurements and Benchmark (KMB) datasets. We present two selective analyses of these datasets: (a) a notional border monitoring scenario that highlights the benefits of a network of counters compared to individual detectors, and (b) new insights into the Sequential Probability Ratio Test (SPRT) detection method, which lead to its adaptations for improved detection. Using KMB datasets from an outdoor test, we construct a notional border monitoring scenario, wherein twelve 2 *2 NaI detectors are deployed on the periphery of 21*21meter square region. A Cs-137 (175 uCi) source is moved across this region, starting several meters from outside and finally moving away. The measurements from individual counters and the network were processed using replays of a particle filter algorithm developed under IRSS program. The algorithm outputs from KMB datasets clearly illustrate the benefits of combining measurements from all networked counters: the source was detected before it entered the region, during its trajectory inside, and until it moved several meters away. When individual counters are used for detection, the source was detected for much shorter durations, and sometimes was missed in the interior region. The application of SPRT for detecting radiation sources requires choosing the detection threshold, which in turn requires a source strength estimate, typically specified as a multiplier of the background radiation level. A judicious selection of this source multiplier is essential to achieve optimal detection probability at a specified false alarm rate. Typically, this threshold is chosen from the Receiver Operating Characteristic (ROC) by varying the source multiplier estimate. ROC is expected to have a monotonically increasing profile between the detection probability and false alarm rate. We derived ROCs for multiple indoor tests using KMB datasets, which revealed an unexpected loop shape: as the multiplier increases, detection probability and false alarm rate both increase until a limit, and then both contract. Consequently, two detection probabilities correspond to the same false alarm rate, and the higher is achieved at a lower multiplier, which is the desired operating point. Using the Chebyshev s inequality we analytically confirm this shape. Then, we present two improved network-SPRT methods by (a) using the threshold off-set as a weighting factor for the binary decisions from individual detectors in a weighted majority voting fusion rule, and (b) applying a composite SPRT derived using measurements from all counters.

Rao, Nageswara S [ORNL; Brooks, Richard R [Clemson University; Wu, Qishi [University of Memphis

2014-01-01

84

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

85

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

86

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.''

87

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.)

88

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

89

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

International Nuclear Information System (INIS)

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 ?-ray (60Co and 137Cs), 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 60Co or 137Cs 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.)

90

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.)

91

Indirect detection of radiation sources through direct detection of radiolysis products  

Energy Technology Data Exchange (ETDEWEB)

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

92

Radiation, ionization, and detection in nuclear medicine  

International Nuclear Information System (INIS)

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 electrievice 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.

93

Radiation detection technique on the fishery foods  

International Nuclear Information System (INIS)

According to necessity on preliminary establishment of a technique to detect scientifically conducts of radiation to individual food such as fishery foods and on preparation of a detectable system, the present project was started under five year planning since 1994 fiscal year to aim referring research results of the agricultural and the fishery products and the species because of beginning to publish those reaching actual area and finding a detection technique based on fishery features. In 1996 fiscal year, in order to study further on adaptability of tyrosine isomer for detection index in shrimps, relationships between radiation dose and production of the tyrosine isomer were examined. And, for detection index of fisheries, in order to search probability of hydro-carbon production in irradiated fisheries was attempted and a relationship between its production and radiation dose was investigated. (G.K.)

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

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

96

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

97

Portable radiation detection system for pulsed high energy photon sources  

International Nuclear Information System (INIS)

Portable, battery-operated, radiation detection systems for measuring the intensity and energy characteristics of intense, pulsed photon sources (either high energy X-ray or gamma) have been developed at the Idaho National Engineering Laboratory. These field-deployable, suitcase-sized detection units are designed to measure and record the characteristics of a single radiation burst or multiple bursts from a pulsed ionizing radiation source. The recorded information can then be analyzed on a simple laptop computer at a location remote from the detection system and completely independent of the ongoing data acquisition process. Two detection unit designs are described. The first, called the MARK-1, has eight bismuth germanate (BGO) radiation detectors. Four of which are unshielded and have different thicknesses (diameters). The remaining four are the same size as the largest unshielded detector but have different thicknesses of lead shielding surrounding each detector. The second unit design, called the MARK-1 A, utilizes the same detection methodology as the MARK-1 but has ten BGO detectors instead of eight and utilizes a different method of amplifying detector signals enabling reduced overall size and weight of the detection unit. Both the detection system designs have sensitivity ranges from 3 x 10-9 cGy to 9 x 10-5 cGy per radiation burst. Experimental detection results will be presented and discussed along the systems' potential for commerciallong the systems' potential for commercial applications

98

Analysis to stray radiation of infrared detecting system  

Science.gov (United States)

In order to improve the detecting ability of dark target by infrared detecting system, stray radiation of the system should be studied before and suppression methods should be adopted. In the infrared detecting system, thermal emission of a room-temperature instrument may be several orders of magnitude larger than the flux of sources of target to be observed. When baffles and vanes are designed to suppress the stray radiation coming from sources outside of the field of view of the detecting system, their thermal radiation should be discussed together. In this article, the stray radiation of thermal emission of infrared detecting system is studied. How to design baffles, vanes and stops is introduced. Their structure models are established in TracePro. Their thermal emissions are simulated and analyzed by ray tracing program. The number of photons on a pixel which emitted from suppression structure which varies from 260K to 310K is given by simulation. From the simulation result, we can find that the stray radiation of thermal emission from inner baffle of primary mirror is the predominant source; The stray radiation of thermal emission of system with vanes on main tube is slightly bigger than that of the system with no vanes; the field stop placed at the first image plane can effectively decrease the number of photons of stray radiation.

Niu, Jin-xing; Shi, Shuheng; Zhou, Ren-kui

2011-08-01

99

Failure detection method for reactor fuel  

International Nuclear Information System (INIS)

The present invention (1) specifies a failed fuel element without dismantling a fuel assembly of an FBR type reactor, (2) determines the scale of the failure without dismantling the fuel assembly, (3) specifies the failed fuel element and determines the scale of the failure at high accuracy, rapidly and at low cost, and (4) detects the failure while eliminating wastes. That is, a radiation detector detects radiation emitted from the surface of a fuel assembly. The radiation detector and the fuel assembly are relatively rotated and moved in parallel with each other. The data for the radiation intensity during the rotation and parallel movement are processed and tomographic images of a radiation intensity distribution are formed and displayed. With such procedures, the position of the failed fuel element in the fuel assembly can be determined using an ECT (Emission Computer Tomographic) method using the radioactivity of its own as a radiation source. As a result, the failure of elements can be detected at high efficiency and accurately. (I.S.)

100

Bayesian Methods for Radiation Dosimetry  

International Nuclear Information System (INIS)

The application of Bayesian methods to calibration for external dosimetry and to compartmental analysis for internal radiation dosimetry is discussed. The calibrative density for chromosome aberration data with imprecise radiation doses was derived to describe the uncertainty of the neutron dose received by an individual with observed dicentric chromosome aberrations. For compartmental analysis, the posterior densities, expectations, and standard deviations of the models' transfer rates and time-dependent expectations and standard deviations for the 45Ca activity in a bone surface compartment were derived

101

Nonlinear Multiantenna Detection Methods  

OpenAIRE

A nonlinear detection technique designed for multiple-antenna assisted receivers employed in space-division multiple-access systems is investigated. We derive the optimal solution of the nonlinear spatial-processing assisted receiver for binary phase shift keying signalling, which we refer to as the Bayesian detector. It is shown that this optimal Bayesian receiver significantly outperforms the standard linear beamforming assisted receiver in terms of a reduced bit error rate, at the expense...

Chen Sheng; Hanzo Lajos; Wolfgang Andreas

2004-01-01

102

Technique for stabilization of detected x-radiation flux  

International Nuclear Information System (INIS)

A method for stabilization of recorded X-radiation flux is proposed. Stabilization is attained due to the fact that different signs of changes in comparable counting rates cause changes in the position of the detected radiation flux peak. Use of the proposed method of stabilizing X-radiation has the following advantages: it obviates limitations connected with sealing and thermostatting detectors; enlarges the number of problems which can be solved with the help of X-ray radiometric equipment; increases the lifetime of radioisotope sources. The given stabilization technique may be used in radioisotope instruments when measuring the density, coating thicknesses and dust content

103

10 CFR 39.33 - Radiation detection instruments.  

Science.gov (United States)

...2010-01-01 2010-01-01 false Radiation detection instruments. 39.33...REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.33 Radiation detection instruments....

2010-01-01

104

Material for ionizing radiation detection  

International Nuclear Information System (INIS)

New scintillation material is claimed, namely, a lead dichloride single crystal activated with europium within 0.01 mol.% and 5 mol.%. For the same size and the same detector-source configuration, the detection efficiency of the PbCl2(Eu) material is better by up to 40% than the conventional NaI(Tl). Thus, for the same detection efficiency the detector element of the new material can significantly be reduced in size. The PbCl2(Eu) single crystal was grown by crystallization from the melt, finished into a cylindrical shape and encased in metal with a glass front window. The single crystal is attached to the window using silicone oil. Magnesium oxide powder is used as a reflector between the crystal and the case. (M.D.)

105

Detection of radiation pressure from solar chameleons  

CERN Document Server

The radiation pressure due to reflected chameleons is suggested for their detection. Sensitive photon radiation pressure or force measuring techniques could become the new antennas for chameleons or other particles with similar properties, with gravitational waves antennas being also of potential interest. This is eventually only at first sight a Gedankenexperiment. Also chameleon-through-a-wall experiments, in particular when equipped with a Fabry-Perot resonator, could apply the suggested techniques.

Baker, O K; Semertzidis, Y K; Upadhye, A; Zioutas, K

2012-01-01

106

Detection of radiation pressure from solar chameleons  

OpenAIRE

The radiation pressure due to reflected chameleons is suggested for their detection. Sensitive photon radiation pressure or force measuring techniques could become the new antennas for chameleons or other particles with similar properties, with gravitational waves antennas being also of potential interest. This is eventually only at first sight a Gedankenexperiment. Also chameleon-through-a-wall experiments, in particular when equipped with a Fabry-Perot resonator, could app...

Baker, O. K.; Lindner, A.; Semertzidis, Y. K.; Upadhye, A.; Zioutas, K.

2012-01-01

107

GaTe semiconductor for radiation detection  

Science.gov (United States)

GaTe semiconductor is used as a room-temperature radiation detector. GaTe has useful properties for radiation detectors: ideal bandgap, favorable mobilities, low melting point (no evaporation), non-hygroscopic nature, and availability of high-purity starting materials. The detector can be used, e.g., for detection of illicit nuclear weapons and radiological dispersed devices at ports of entry, in cities, and off shore and for determination of medical isotopes present in a patient.

Payne, Stephen A. (Castro Valley, CA); Burger, Arnold (Nashville, TN); Mandal, Krishna C. (Ashland, MA)

2009-06-23

108

Undoped polycarbonate for detection of environmental radiation  

International Nuclear Information System (INIS)

The enormous area of damage to Japan's Fukushima Daiichi nuclear power plant requires radiation detectors with robust base substrates to monitor high-dose-rate environmental radiation with long-term stability. Undoped aromatic ring polymers have considerable potential as base substrates in radiation detection. Here, we characterise polycarbonate (PC), which has excellent transparency, shock, radiation, and weather resistance, heat tolerance, and anti-abrasion qualities. It has a density of 1.20 g/cm3, an excitation maximum of 310 nm, and short-wavelength emission with a maximum at 350-nm. By taking into account its emission spectrum, we determined an effective refractive index of 1.64. PC has a light yield that is 0.67 times that of undoped poly (ethylene terephthalate). These results reveal that readily available PC is an effective base substrate for use in large-area radiation detectors for the nuclear power plant recovery process. (author)

109

A Voltage Quality Detection Method  

DEFF Research Database (Denmark)

This paper presents a voltage quality detection method based on a phase-locked loop (PLL) technique. The technique can detect the voltage magnitude and phase angle of each individual phase under both normal and fault power system conditions. The proposed method has the potential to evaluate various power quality disturbances, such as interruptions, sags and imbalances. Simulation studies have been performed. The effectiveness of the proposed method has been demonstrated under the simulated typical power disturbances.

Chen, Zhe; Wei, Mu

2008-01-01

110

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

111

Detection of DNA–protein crosslinks (DPCs) by novel direct fluorescence labeling methods: distinct stabilities of aldehyde and radiation-induced DPCs  

OpenAIRE

Proteins are covalently trapped on DNA to form DNA–protein crosslinks (DPCs) when cells are exposed to DNA-damaging agents. DPCs interfere with many aspects of DNA transactions. The current DPC detection methods indirectly measure crosslinked proteins (CLPs) through DNA tethered to proteins. However, a major drawback of such methods is the non-linear relationship between the amounts of DNA and CLPs, which makes quantitative data interpretation difficult. Here we developed novel methods of D...

Shoulkamy, Mahmoud I.; Nakano, Toshiaki; Ohshima, Makiko; Hirayama, Ryoichi; Uzawa, Akiko; Furusawa, Yoshiya; Ide, Hiroshi

2012-01-01

112

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

113

Surface property detection apparatus and method  

Science.gov (United States)

Apparatus and method for detecting, determining, and imaging surface resistance corrosion, thin film growth, and oxide formation on the surface of conductors or other electrical surface modification. The invention comprises a modified confocal resonator structure with the sample remote from the radiating mirror. Surface resistance is determined by analyzing and imaging reflected microwaves; imaging reveals anomalies due to surface impurities, non-stoichiometry, and the like, in the surface of the superconductor, conductor, dielectric, or semiconductor. 4 figs.

Martens, J.S.; Ginley, D.S.; Hietala, V.M.; Sorensen, N.R.

1995-08-08

114

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

115

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

116

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

117

A new vehicle detection method  

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a new vehicle detection method from images acquired by cameras embedded in a moving vehicle. Given the sequence of images, the proposed algorithms should detect out all cars in realtime. Related to the driving direction, the cars can be classified into two types. Cars drive in the same direction as the intelligent vehicle (IV and cars drive in the opposite direction. Due to the distinct features of these two types, we suggest to achieve this method in two main steps. The first one detects all obstacles from images using the so-called association combined with corner detector. The second step is applied to validate each vehicle using AdaBoost classifier. The new method has been applied to different images data and the experimental results validate the efficacy of our method.

Zebbara Khalid

2011-09-01

118

Calculating gamma radiation field gradient by the Monte Carlo method  

International Nuclear Information System (INIS)

An algorithm for direct calculation of gradients of photon flux density, energy flux and radiation doze by the Monte Carlo method is suggested. Local evaluation for a point detector, depending on collision ooint and scattering angle cosine is applied to calculate ?-radiation flux density gradient in the point of detecting. Results of calculating the scattered radiation flux density and the corresponding gradient behind the indefinite two-layer barrier of aluminium and carbon are presented as an example

119

Methods for screening radiation-induced mutations in fish  

International Nuclear Information System (INIS)

The available methods for the detection of radiation-induced mutations in teleost fish are reviewed. The importance of proper irradiation procedures combined with timing of gametogenesis is stressed. Several qualitative abnormalities of the vertebral system can be used as sensitive indicators of radiation damage which can be quantified in certain circumstances. In addition, behaviour and viability are two general characteristics that can also be used to assess low-level radiation-induced mutations. (author)

120

Detection of radiation processing in onions  

International Nuclear Information System (INIS)

Two breeds of onions were used for irradiation. Both breeds were divided into two parts - the first was irradiated with a dose of 80 Gy and the second served as a control. The two parts were stored under the same conditions. Conductometry, liquid chromatography and spectrophotometry were used for detecting the radiation processing of the onions. Only from the spectrophotometric determination of 2-desoxysaccharides it was possible to safely distinguish irradiated onions from non-irradiated controls throughout storage time. (E.S.)

121

Spices, irradiation and detection methods  

International Nuclear Information System (INIS)

This paper is about microbiological aspects of spices and microbiological methods to detect irradiated food. The proposed method is a combination of the Direct Epifluorescence Filter Technique (DEFT) and the Aerobic Plate Count (APC). The evidence for irradiation of spices is based on the demonstration of a higher DEFT count than the APC. The principle was first tested in our earlier investigation in the detection of irradiation of whole spices. The combined DEFT+APC procedure was found to give a fairly reliable indication of whether or not a whole spice sample had been irradiated. The results are given (8 figs, 22 refs)

122

Radiation detection and wireless networked early warning  

Science.gov (United States)

We have designed a compact, wireless, GPS-enabled array of inexpensive radiation sensors based on scintillation counting. Each sensor has a scintillator, photomultiplier tube, and pulse-counting circuit that includes a comparator, digital potentiometer and microcontroller. This design provides a high level of sensitivity and reliability. A 0.2 m2 PV panel powers each sensor providing a maintenance-free 24/7 energy source. The sensor can be mounted within a roadway light-post and monitor radiological activity along transport routes. Each sensor wirelessly transmits real-time data (as counts per second) up to 2 miles with a XBee radio module, and the data is received by a XBee receive-module on a computer. Data collection software logs the information from all sensors and provides real-time identification of radiation events. Measurements performed to-date demonstrate the ability of a sensor to detect a 20 ?Ci source at 3.5 meters when packaged with a PVT (plastic) scintillator, and 7 meters for a sensor with a CsI crystal (more expensive but ~5 times more sensitive). It is calculated that the sensor-architecture can detect sources moving as fast as 130 km/h based on the current data rate and statistical bounds of 3-sigma threshold detection. The sensor array is suitable for identifying and tracking a radiation threat from a dirty bomb along roadways.

Burns, David A.; Litz, Marc S.; Carroll, James J.; Katsis, Dimosthenis

2012-06-01

123

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

International Nuclear Information System (INIS)

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.

124

Detection methods for irradiated foods  

International Nuclear Information System (INIS)

In connection with the ongoing world application of irradiation as a technology in Food industry for increasing food safety, it became a need for methods of identification of irradiation. It was required to control international trade of irradiated foods, because of the certain that legally imposed food laws are not violated; supervise correct labeling; avoid multiple irradiation. Physical, chemical and biological methods for detection of irradiated foods as well principle that are based, are introducing in this summary

125

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

126

Dosimetry methods for the estimation of exposure to ionizing radiation  

International Nuclear Information System (INIS)

Ionizing radiations, by their nature, have required for their detection the use of suitable devices generically referred detecting systems. The detection of secondary particles arising during the processes of ionization and excitation to the passage of radiation in the environment, have constituted the basis of the measurement methods. A detector system is a device that converts the energy of the incident radiation on a signal (electrical, photochemical, etc.) that is easily processable from the technological point of view, but without distorting the original information. These devices have provided qualitative or quantitative information about the radiation of interest. The detector system is a set of a detector together with a processing system. This system has based its operation in methods of: gas ionization, scintillation, semiconductor, film, thermoluminescence, among others. (author)

127

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

128

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)

129

Various Edge Detection Methods for Foreground Detection?  

OpenAIRE

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 o...

Gurjeet kaur Seerha; Rajneet Kaur

2013-01-01

130

Outlier detection method in GEEs.  

Science.gov (United States)

The generalized estimating equations (GEEs) method has become quite useful in modeling correlated data. However, diagnostic tools to check that the selected final model fits the data as accurately as possible have not been explored intensively. In this paper, an outlier detection technique is developed based on the use of the "working" score test statistic to test an appropriate mean-shift model in the context of longitudinal studies based on GEEs. Through a simulation study it has been shown that this method correctly singled out the outlier when the data set had a known outlier. The method is applied to a set of data to illustrate the outlier detection procedure in GEEs. PMID:24740488

Pardo, María Del Carmen; Hobza, Tomáš

2014-04-17

131

Detecting transition radiation from a magnetic moment.  

Science.gov (United States)

Electromagnetic radiation can be emitted not only by particle charges but also by magnetic moments and higher electric and magnetic multipoles. However, experimental proofs of this fundamental fact are extremely scarce. In particular, the magnetic moment contribution has never been observed in any form of polarization radiation. Here, we propose to detect it using vortex electrons carrying large orbital angular momentum ?. The relative contribution of the orbital angular momentum-induced magnetic moment, ???/Ee, becomes much larger than the spin-induced contribution ??/E and it can be observed experimentally. As a particular example, we consider transition radiation from vortex electrons obliquely incident on an interface between a vacuum and a dispersive medium, in which the magnetic moment contribution manifests itself via a left-right angular asymmetry. For electrons with Ee=300??keV and ?=100-1000, we predict an asymmetry of the order of 0.1%-1%, which could be measured with existing technology. Thus, vortex electrons emerge as a new tool in the physics of electromagnetic radiation. PMID:23848881

Ivanov, Igor P; Karlovets, Dmitry V

2013-06-28

132

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

133

Radiation induced methods of labeling  

International Nuclear Information System (INIS)

In biomedical research labeled molecules are required as tracers for radioimmunoassay, distribution, metabolism and functional studies at the cellular levels. These labeled molecules may encompass a wide range of compounds from drugs, natural plant products, antibiotics, glucosides, etc. to peptides and proteins. Tagging these molecules with carbon-14 involves elaborate chemical syntheses that are often laborious and costly, and in many cases chemical syntheses are not even feasible. The long life of carbon-14 also limits the maximum specific activity that can be achieved with carbon-14 labeled compounds to 62 mCi per millimole. For radiobinding assays and receptor studies labeled substances of this relatively low specific activity lack the sensitivity required and compounds labeled at higher specific activities with tritium are more desirable. Tritiu, the radioactive isotope of hydrogen, has a specific activity of 29 Ci per milliatom or 58 Ci per millimole in the carrier-free state. Since hydrogen binds by 1s orbital to carbon, nitrogen and oxygen atoms in the organic molecule, it is highly likely that the hydrogen atoms in organic compounds can be exchanged with tritium atoms without the disruption of the carbon skeleton. In this paper the authors compare the merits and limitations of the various radiation-induced methods of labeling with tritium gas and point out the trends for future development

134

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

135

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

136

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

137

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

138

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

139

Detecting transition radiation from a magnetic moment  

CERN Document Server

Electromagnetic radiation can be emitted not only by particles' charges but also by magnetic moments and higher electric and magnetic multipoles. However experimental proofs of this fundamental fact are extremely scarce. In particular, the magnetic moment contribution has never been observed in any form of polarization radiation. Here, we propose to detect it using vortex electrons carrying large orbital angular momentum (OAM) $\\ell$. The relative contribution of the OAM-induced magnetic moment, $\\ell \\hbar \\omega/E_e$, becomes much larger than the spin-induced contribution $\\hbar \\omega/E_e$, and it can be observed experimentally. As a particular example, we consider transition radiation from vortex electrons obliquely indicent on a boundary between vacuum and a dispersive medium, in which the magnetic moment contribution manifests itself via angular asymmetry. For electrons with $E_e = 300$ keV and $\\ell = 100-1000$ we predict asymmetry of order 0.1%-1%, which could be measurable with existing technology. T...

Ivanov, Igor P

2013-01-01

140

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

141

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

142

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

143

Nuclear radiation detected optical pumping of neutron deficient Hg isotopes  

International Nuclear Information System (INIS)

The extension of the Nuclear Radiation Detected Optical Pumping method to mass-separated samples of isotopes far off stability is presented for a series of light Hg isotopes produced at the ISOLDE facility at CERN. The isotope under investigation is transferred by an automatic transfer system into the optical pumping apparatus. Zeeman scanning of an isotopically pure Hg spectral lamp is used to reach energetic coincidence with the hyperfine structure components of the 6s21S0-6s6p3P1 (lambda = 2537 A) resonance line of the investigated isotope and the Hg lamp. The orientation build up by optical pumping is monitored via the asymmetry or anisotropy of the nuclear radiation. Nuclear spins, magnetic moments, electric quadrupole moments and isotopic shift are obtained for 181Hg-191Hg using the ?-asymmetry as detector. The extension of the method using the ?-anisotropy is discussed and measurements on 193Hg are presented. (orig./HK)

144

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

145

Detecting solar chameleons through radiation pressure  

Science.gov (United States)

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 results from a force/pressure sensor, currently under development at INFN Trieste, to be mounted in the focal plane of one of the X-Ray telescopes of the CAST experiment at CERN. We show, that such an experiment signifies a pioneering effort probing uncharted chameleon parameter space.

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

2014-12-01

146

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

Energy Technology Data Exchange (ETDEWEB)

Meat (beef, pork, chicken) and nut (sesame, perilla, black sesame, peanut) were irradiated with /sup 60/Co gamma-ray. A process to detect radiation-induced hydrocarbons and 2-alkylcyclobutanones includes the extraction of fat from meat and nut, separation of hydrocarbons and 2-alkylcyclobutanones with a florisil column and identification of GC/MS methods. Concentrations of the produced hydrocarbons and 2-alkylcyclobutanones tended to increase linearly with the dose levels of irradiation in beef, pork and chicken, while concentrations of radiation-induced hydrocarbons were different individually at the same dose level. In meat, hydrocarbons and 2-alkylcyclobutanones originated from oleic acid were found in a large amount. The concentrations of radiation-induced hydrocarbons were relatively constant during 16 weeks. In nut, hydrocarbons originated from oleic acid and linoleic acid were the major compounds whereas results of perilla was similar to meat. Radiation-induced hydrocarbons were increased linearly with the irradiation dose and remarkably detected at 0.5 kGy and over. 44 refs., 30 figs., 14 tabs. (Author)

Kim, Kyong Su; Kim, Sun Min; Park, Eun Ryong; Lee, Hae Jung; Kim, Eun Ah; Jo, Jung Ok [Chosun University, Kwangju (Korea)

1999-04-01

147

System and method for administering radiation  

International Nuclear Information System (INIS)

A system and method for metering the quantity of radiation administered a subject by a source of radiation movable along a path relative to the subject is described. The system cumulatively counts the amount of radiation directed toward the subject during each of a succession of increments of motion of the source. When a predetermined amount of radiation is delivered during an increment, the source is disabled until the source passes into the next increment of displacement. The count of radiation is restarted at the instant the source is disabled, to accumulate accurately any added spurious radiation dosage which may occur and to include that dosage in the count of the permitted amount for the next succeeding increment of motion. Several interlocks for disabling the system in response to various malfunctions are included. Means for controlling the speed of movement of the source and/or the dose rate of the source are also included. (auth)

148

Radiation detection and diagnosis of breast cancer  

International Nuclear Information System (INIS)

The value of mammography in the symptomatic patient has been adequately documented, but its use as a detection procedure remains a question. Risk-benefit ratios, based primarily upon the study carried out by the Health Insurance Plan of Greater New York, have suggested that the technique has little value in individuals under age 50. Emphasis has been placed upon the possible carcinogenic effects of radiation as compared with the efficacy of mammography and the questionable influence of early diagnosis upon end results. Although technical advances have substantially reduced the exposure of the patient to radiation, the possibility of significant information loss as the result of these developments has been considered a potential drawback to their routine use. All of these factors have served to diminish both public and professional acceptance of the examination. Although current data do not allow complete resolution of these problems, certain conclusions may be drawn and trends established. The sum of these may indicate that minimal dose mammography is an accurate, low-risk procedure, capable of significantly altering the natural history of breast cancer. Whether or not the examination should be routinely used in women under age 50 remains open to question since the lack of experimental controls prohibits validation of the technique in terms of reduced mortality rates. Documentation of increased survival rates may partially assist in the established of a reliable risk-ist in the established of a reliable risk-benefit ratio, but will not satisfy the statistical requirements of eliminating lead-bias, and self-selection. These questions may be resolved by studies now underway

149

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

150

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

151

Evaluation of Gamma Radiation Field By Response Matrix Method  

International Nuclear Information System (INIS)

Application of response matrix method for evaluating gamma radiation field in the vicinity of nuclear facilities measured with a NaI(TI) gamma spectrometer is briefly described. Some evaluation results on the elevated exposure in the vicinity of the Radioisotope Production Center and in the RSG-GAS building, as well as concentrations determination of 238U, 232Th, and 40K in the environment are presented. The elevated exposure due to the activity of the Radiation Production Center as low as 0.54 uR/hour could be detected properly by using the response matrix method

152

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

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

Shot Boundary Detection Method for News Video  

Directory of Open Access Journals (Sweden)

Full Text Available It is very important to detect shot boundary accurately and quickly in a large number of news video data. Therefore, we proposed a new method with dual-detection model. The method is divided into two stages, i.e. pre-detection and re-detection. In the pre-detection stage, the uneven blocked differences based on the feature of human vision are presented and used in adaptive binary search to detect shot boundaries. In the re-detection round, Speeded Up Robust Features (SURF method is applied to exclude false detections. The experimental results show that this method can detect abrupt boundaries of news video quickly and accurately.

Ming Jiang

2013-12-01

155

A New Bilirubin Concentration Detection Method by Light Reflection  

CERN Document Server

A new and simple method of blood bilirubin detection through light reflection from skin is developed. The basic improvement over the existing methods is in the design of the light emitter and detector geometry which facilitates a two-stream plane parallel homogenous medium solution to the emitting-scatterig radiative transfer equation. The forward peak in the scattering phase function that is characteristic of water droplets and water filled media is accounted for through a proper method named delta-Eddington approximation.

Subasilar, B

1999-01-01

156

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

157

Proceedings of the symposium on Nuclear Radiation Detection Materials  

International Nuclear Information System (INIS)

This symposium provides a venue for the presentation of the latest results and discussion of radiation detection materials from both experimental and theoretical standpoints. As advances are made in this area of materials, additional experimental and theoretical approaches are used to both guide the growth of materials and to characterize the materials that have a wide array of applications for detecting different types of radiation. The types of detector materials for semiconductors and scintillators include a variety of molecular compounds such as lanthanum halides (LaX3), zinc oxide (ZnO), lead iodide (PbI2), cadmium telluride (CdTe), mercuric iodide (HgI2), thallium bromide (TlBr), as well as others, such as cadmium zinc telluride (CZT). An additional class of scintillators includes those based on organic compounds and glasses. Ideally, desired materials used for radiation detection have attributes such as appropriate-range band-gaps, high atomic numbers of the central element, high densities, performance at room temperature, and strong mechanical properties, and are low cost in terms of their production. There are significant gaps in the knowledge related to these materials that are very important in making radiation detector materials that are higher quality in terms of their reproducible purity, homogeneity, and mechanical integrity. The topics that are the focal point of this symposium address these issues so that much better daddress these issues so that much better detectors may be made in the future. Topics cover the following areas: - Material growth: on-going developments regarding cadmium telluride (CdTe), cadmium zinc telluride (CZT), mercuric iodide (HgI2), cadmium manganese telluride (CMT), LaX3, and all other detector materials; new materials with potential for radiation detection (II-VI, III-VI, III-VII compounds, neutron detectors, nano-materials, and ceramic scintillators); purification techniques; and growth methods; - Characterization: experimental results; methodologies; defect structure; surface and bulk effects; and interfacial phenomena (contacting, contact adhesion, crystallographic polarity, Schottky barrier, and surface passivation); - Physical and mechanical properties: electric charge compensation mechanisms, charge collection, and thermal transport; hardness; and plasticity; - New and innovative characterization techniques: optical spectroscopy; microscopy (SEM, TEM, STM, AFM, etc.); synchrotron mapping and X-ray diffraction; rocking curves; and spectroscopy (IR, Raman, NMR, XPS, Auger, and other applicable approaches); - Theoretical studies: bandgap calculations; mobility calculations; scintillator material physics; thermal modeling; crystal growth; processes in material matrices; and processes in amorphous and crystalline matrices

158

Particle detection systems and methods  

Science.gov (United States)

Techniques, apparatus and systems for detecting particles such as muons and neutrons. In one implementation, a particle detection system employs a plurality of drift cells, which can be for example sealed gas-filled drift tubes, arranged on sides of a volume to be scanned to track incoming and outgoing charged particles, such as cosmic ray-produced muons. The drift cells can include a neutron sensitive medium to enable concurrent counting of neutrons. The system can selectively detect devices or materials, such as iron, lead, gold, uranium, plutonium, and/or tungsten, occupying the volume from multiple scattering of the charged particles passing through the volume and can concurrently detect any unshielded neutron sources occupying the volume from neutrons emitted therefrom. If necessary, the drift cells can be used to also detect gamma rays. The system can be employed to inspect occupied vehicles at border crossings for nuclear threat objects.

Morris, Christopher L.; Makela, Mark F.

2010-05-11

159

Active methods of early forest fire detection  

Science.gov (United States)

A method of automated early fire detection based on the light detection and ranging (lidar) technology is presented. Specific lidar configurations and their application to forest and industrial-environment fire surveillance are discussed.

Utkin, Andrei B.; Lavrov, Alexander; Vilar, Rui

2011-02-01

160

Method of manufacturing dosemeter detection element  

International Nuclear Information System (INIS)

A method is proposed of manufacturing detection components of thermoluminescent dosemeters for ionizing electromagnetic, cathode and uv radiations. The initial material is glass powder with the composition 82 to 90% (w/w) of P2O5, 3 to 8% (w/w) of MgO, 3 to 12% (w/w) of SrO, 3 to 8% (w/w) of Al2O3, and 0.05 to 0.15% (w/w) of MnO. The powder, which consists of 90 to 99.9% (w/w) grain not exceeding 0.315 mm in size, is compacted and sintered at a temperature of 650 to 800 degC for 50 to 70 min and is let to cool spontaneously. Detection bodies of any desired shape may thus be produced. The resulting dosimetric properties of the bodies are identical to those produced by cutting the initial glass melt. Production costs are lower, and glass waste from previous production or from glass manufacturing plants of suitable composition may be used. A sintered glass products shows better homogeneity and dosemeters made using the glass have a lower scatter of physical characteristics. (M.S.)

161

Detection of the strange bodies on the conveyor belt using gamma radiation technique  

International Nuclear Information System (INIS)

The aim of this paper is to present a method for the computation of the activity of a gamma radiation source used in a radiometric assembly designed to detect the strange bodies (iron, stone or wood-made granules) within the textile material on the conveyor belt. The mathematical modelling method based on the Monte Carlo procedure has been used, with different values of the errors of types I and II; the investigation method is the transmission of gamma radiations. (Author)

162

RADIATION and NUCLEAR MATERIALS DETECTION RESEARCH AND DEVELOPMENT AT ORNL  

International Nuclear Information System (INIS)

Research and development is underway to improve radiation and nuclear detection capabilities. This research and development in radiation and nuclear detection includes areas such as advanced materials, applied research and engineering for designing and fabricating customized detection equipment, and theoretical modeling and computational support. Oak Ridge National Laboratory (ORNL) has a distinctive set of detector materials fabrication and characterization capabilities and recently created a Center for Radiation Detection Materials and Systems. Applied research and engineering efforts have led to the development of improved detectors for specific applications including safeguards, treaty monitoring, and science experiments. All sizes, types, and capabilities of detector systems have been addressed from miniature to man-portable and from neutrons to gamma radiation. Dedicated test beds, in-house and in the field, have been established to analyze, characterize, and improve detection systems

163

Method For Detecting Biological Agents  

Science.gov (United States)

A sensor is provided including a polymer capable of having an alterable measurable property from the group of luminescence and electrical conductivity, the polymer having an intermediate combination of a recognition element, a tethering element and a property-altering element bound thereto and capable of altering the measurable property, the intermediate combination adapted for subsequent separation from the polymer upon exposure to an agent having an affinity for binding to the recognition element whereupon the separation of the intermediate combination from the polymer results in a detectable change in the alterable measurable property, and, detecting said detectable change in the alterable measurable property.

Chen, Liaohai (Los Alamos, NM); McBranch, Duncan W. (Santa Fe, NM); Wang, Hsing-Lin (Los Alamos, NM); Whitten, David G. (Santa Fe, NM)

2005-12-27

164

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

165

Investigation of detection technique of irradiated food. Detection of irradiated food by TL method  

International Nuclear Information System (INIS)

Thermo luminescence (TL) method, one of detection method of irradiated food, was applied to black pepper. The inorganic substances such as dust, sand and soil adhered to food can capture irradiation energy and emit it by heat as luminescence. Black pepper of Turkey and Malaysia were irradiated 0.5-10KGy dose from 60Co radiation source. Although different TL emission curves were observed by the place of production and the particle size of inorganic substance adhered, the strength of emission was constant for a long time. The results proved that this method was a good detection method for irradiated food adhered inorganic substances. (S.Y.)

166

Approximation methods in gravitational-radiation theory  

Science.gov (United States)

The observation of gravitational-radiation damping in the binary pulsar PSR 1913 + 16 and the ongoing experimental search for gravitational waves of extraterrestrial origin have made the theory of gravitational radiation an active branch of classical general relativity. In calculations of gravitational radiation, approximation methods play a crucial role. Recent developments are summarized in two areas in which approximations are important: (a) the quadrupole approxiamtion, which determines the energy flux and the radiation reaction forces in weak-field, slow-motion, source-within-the-near-zone systems such as the binary pulsar; and (b) the normal modes of oscillation of black holes, where the Wentzel-Kramers-Brillouin approximation gives accurate estimates of the complex frequencies of the modes.

Will, C. M.

1986-01-01

167

Detection of nonthermal continuum radiation in Saturn's magnetosphere  

International Nuclear Information System (INIS)

A detailed analysis of high resolution wideband data from the Voyager 1 and 2 plasma wave receivers has revealed the presence of heretofore undiscovered nonthermal continuum radiation trapped within the Saturnian magnetosphere. The discovery of Saturnian trapped continuum radiation fills a disturbing void in the Saturnian radio spectrum. On the basis of observations at both the Earth and Jupiter it was expected that continuum radiation should be a pervasive signature of planetary magnetospheres in general. Special processing of the Voyager 1 plasma wave data at Saturn has now confirmed the existence of weak emissions that have a spectrum characteristic of trapped continuum radiation. Similar radiation was also detected by Voyager 2; however, in this case it is not certain that Saturn was the only source. Considerable evidence exists which suggests that Saturn may have been immersed in the Jovian tail during the Voyager 2 encounter, so that Jupiter may provide an additional source of the continuum radiation detected by Voyager 2

168

Method of sintering materials with microwave radiation  

Science.gov (United States)

A method of sintering ceramic materials following: A compacted article comprising inorganic particles coated with carbon is provided, the carbon providing improved microwave coupling. The compacted article is then heated by microwave radiation to a temperature and for a period of time sufficient to sinter the compacted article.

Kimrey, Jr., Harold D. (Knoxville, TN); Holcombe, Jr., Cressie E. (Farragut, TN); Dykes, Norman L. (Oak Ridge, TN)

1994-01-01

169

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

170

Control volume finite element method for radiation  

International Nuclear Information System (INIS)

In this paper a new methodology is presented by the authors for the numerical treatment of radiative heat transfer in emitting, absorbing and scattering media. This methodology is based on the utilisation of Control Volume Finite Element Method (CVFEM) and the use, for the first time, of matrix formulation of the discretized Radiative Transfer Equation (RTE). The advantages of the proposed methodology is to avoid problems that confronted when previous techniques are used to predict radiative heat transfer, essentially, in complex geometries and when there is scattering and/or non-black boundaries surfaces. Besides, the new formulation of the discretized RTE presented in this paper makes it possible to solve the algebraic system by direct or iterative numerical methods. The theoretical background of CVFEM and matrix formulation is presented in the text. The proposed technique is applied to different test problems, and the results compared favourably against other published works. Moreover this paper discusses in detail the effects of some radiative parameters, such as optical thickness and walls emissivities on the spatial evolution of the radiant heat flux. The numerical simulation of radiative heat transfer for different cases using the algorithm proposed in this work has shown that the developed computer procedure needs an accurate CPU time and is exempt of any numerical oscillations

171

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

172

Statistical Studies on Sequential Probability Ratio Test for Radiation Detection  

Energy Technology Data Exchange (ETDEWEB)

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.

Warnick Kernan, Ding Yuan, et al.

2007-07-01

173

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

174

Bacillus Spore Inactivation Methods Affect Detection Assays  

OpenAIRE

Detection of biological weapons is a primary concern in force protection, treaty verification, and safeguarding civilian populations against domestic terrorism. One great concern is the detection of Bacillus anthracis, the causative agent of anthrax. Assays for detection in the laboratory often employ inactivated preparations of spores or nonpathogenic simulants. This study uses several common biodetection platforms to detect B. anthracis spores that have been inactivated by two methods and c...

Dang, Jessica L.; Heroux, Karen; Kearney, John; Arasteh, Ameneh; Gostomski, Mark; Emanuel, Peter A.

2001-01-01

175

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

176

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

177

Crosslinking by Gamma Radiation Uniform Irradiation Method  

International Nuclear Information System (INIS)

With crosslinking it is possible to strengthen the physical properties of thermoplastics such as heat resistance and resistance to other decomposing effects. Crosslinking can be achieved either by chemical methods or using high energy ionizing radiation. In this paper, dosimetry and irradiation methods which are used in crosslinking process of 16 mm radius polietilen under- floor heating pipes are explained. Radiation crosslinkable polietilen pipes of 140-160 meter coils in packed form are under nitrogen. Radiation process takes place in tote boxes where in each tote 4 coils of pipes are placed. In each cycle product absorbs 30 kGy of dose and the total number of cycle varies between 4-4.5 depending on the density .In every two cycles the locations of coils are changed in tote boxes in order to achieve more uniform dose distribution. We found that in the dose range of 130 -140 kGy it is possible to achieve 60 % crosslinking level for this type of pipes manufactured by different companies. Normally in our automatic tote box gamma radiation plant the difference between maximum and minimum dose is 40 %. However thanks to this method this ratio is lowered to 13 %. As a result, the maximum dose of 180 kGy is reduced to the range of 150 kGy that caused a reduction in chain scission effect in molecules

178

Detection of radiation damage in organic crystals  

International Nuclear Information System (INIS)

In X-ray diffraction experiments with single crystals, the loss intensity of Bragg reflections caused by radiation damage can become more severe at higher scattering angle, similar to the effect of increased thermal motion or disorder. Long exposure to X-rays can also lead to an increase in the lattice dimensions, similar to the effect of thermal expansion. Both effects are illustrated by observations with 4, 5, 10, 11-tetraoxa-1, 2, 7,8-tetraazatricyclo tetradecane made in connection with a charge density study of this molecule. Recommendations are made for the choice of standard reflections and measurement strategies for accurate crystal structure analysis of radiation sensitive compounds

179

Mammography with synchrotron radiation: phase-detection techniques.  

Science.gov (United States)

The authors evaluated the effect on mammographic examinations of the use of synchrotron radiation to detect phase-perturbation effects, which are higher than absorption effects for soft tissue in the energy range of 15-25 keV. Detection of phase-perturbation effects was possible because of the high degree of coherence of synchrotron radiation sources. Synchrotron radiation images were obtained of a mammographic phantom and in vitro breast tissue specimens and compared with conventional mammographic studies. On the basis of grades assigned by three reviewers, image quality of the former was considerably higher, and the delivered dose was fully compatible. PMID:10751500

Arfelli, F; Bonvicini, V; Bravin, A; Cantatore, G; Castelli, E; Palma, L D; Michiel, M D; Fabrizioli, M; Longo, R; Menk, R H; Olivo, A; Pani, S; Pontoni, D; Poropat, P; Prest, M; Rashevsky, A; Ratti, M; Rigon, L; Tromba, G; Vacchi, A; Vallazza, E; Zanconati, F

2000-04-01

180

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)

181

Methods of measurements on incidental X-radiation from electron tubes  

International Nuclear Information System (INIS)

The standard describes the method for detection of x-radiation and the method for the direct and indirect measurement of field pattern and exposure rate of random incidental radiation emanating from high voltage electron tubes. Required apparatus and calibration procedure for the exposure rate meter or film mount are described. (M.G.B.)

182

Land mine detection by IR temporal analysis: detection method  

Science.gov (United States)

The Swedish Defence Research Agency (FOI) has presented several approaches to temporal analysis of thermal IR data in the application of mine detection during the years. Detection by classification is performed using a number of detection algorithms with varying, in general good, results. The FOI temporal analysis method is tested on images randomly chosen from a diurnal sequence. The test sequence show very little contrast. The reference features are taken from a known object in the scene or from a numerical model of the object of interest. In this paper variations of the method are evaluated on the same test data. Focus is on the question if increased number of data collection times affects the detection rate and false alarm rate. The ROC curves show performance better than random for all of the tested cases, and excellent for some. Detection rate increases and false alarm rate decreases with increased number of images used for some of the tested cases.

Linderhed, Anna; Sjokvist, Stefan; Nyberg, Sten; Uppsall, Magnus

2005-06-01

183

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

184

A Study on Radiation Detection by Using Optical Fibers  

International Nuclear Information System (INIS)

Optical fiber have been investigated for their potential use as sensor material in various nuclear applications. Several new methods of radiation measurement are being developed using recent optical techniques. Comprehensive overviews of their potential use in nuclear environments can be found in measuring temperature, pressure, void fraction and corrosion in nuclear systems. Optical fibers doped with scintillating components in the core have drawn special interests as potential use for radiation detection. As a radiation detector, a scintillating optical fiber can function for dual purpose: scintillator and light transmitter. When a radiation interacts with the core material, scintillator occurs and the resultant light is transmitted through the fiber to an optoelectronic devices such as a photomultiplier tube. Optical fiber sensors have proven to present several advantages as compared to other conventional sensors. They can be processed very small size and light enough to be easily put into very narrow channels such as between nuclear fuel rods. No electrical power is needed to the sensor part so they are less susceptible to trouble in harsh environments such as underground and underwater. Optical fiber sensor cost relatively cheap to make them more suitable for a multi-point distribution radiation monitoring which can be applied in such as nuclear reactors, accelerators, fusion study facilities. Much effort has been exerted on applying scintillating optical fibers on applying scintillating optical fibers to develop radiation detectors. This study has been conducted to investigate feasibility of using scintillating optical fibers and [CsI(Tl)] for detection of gamma rays emitted 137Cs and 60Co and beta rays form 90Sr. The sensors are constructed of single-stand or multi-stand fibers of 1mm and 0.5mm diameter. The glass scintillating fibers used contains cerium-activated lithium-silicate material in Levy Hill Lab model GS20, GS30 and the plastic scintillating fiber used are commercially available Bicron model BCF-12. We used a mirror and lens to improve the efficiency of the sensor with collecting multi-stand plastic scintillating fibers and light transmitting fibers were tested its bending loss of their types. In this paper, we report the pulse-hight spectra obtained by using these sensors, and analyze them in the aspect of their usability for radiation detectors. Our investigation suggests that the glass scintillating fibers can be used to develop gamma ray detectors which will function in high and low gamma ray flux environments. Use of the sensor for the beta ray detection was not satisfactory. Multi-strand plastic scintillating fiber sensors work satisfactorily for the weak gamma sources, but did produce somewhat promising results for beta ray sources. The inorganic scintillator[CsI(Tl)] works satisfactorily both gamma ray sources and beta ray sources

185

Smart Surfaces: New Coatings & Paints with Radiation Detection Functionality  

Energy Technology Data Exchange (ETDEWEB)

Paints are being developed and tested that might ultimately be able to detect radiological agents in the environment by incorporating special pigments into an organic polymeric binder that can be applied as a paint or coatings. These paints detect radioactive sources and contaminants with inorganic or organic scintillation or thermo-luminescent pigments, which are selected based upon the radiation ({alpha}, {beta}, {gamma} or n) to be detected, and are shown in Figure 1.

Farmer, J; Choi, J

2007-03-12

186

Polymer metal lamination by radiation method  

Energy Technology Data Exchange (ETDEWEB)

Conventional technology of polyethylene-metal laminate involves the use of adhesives for laminating. Environmental pollution has been a big problem not easily resolved and processing is complicated. By radiation peroxidation of the surface of polyethylene a simple polyethylene-metal laminate has been produced. Measurements of the mechanical properties and the electrical properties showed the laminating film conforms well with the national standards. It has been found that the adhesive strength of the polyethylene-metal film is affected by irradiation, the metal surface reactivity and cleaning of the laminating surface. Polyethylene-metal film laminated by radiation method is more heat resistant than the film laminated by conventional methods. The laminate materials can be widely used in electrical devices, chemical and packaging industry. (author).

Ma Yizheng; Chen Maoqing; Feng Zhixiong; Sun Dakuan; You Dawei (Shanghai Irradiation Center, SH (China))

187

Polymer metal lamination by radiation method  

International Nuclear Information System (INIS)

Conventional technology of polyethylene-metal laminate involves the use of adhesives for laminating. Environmental pollution has been a big problem not easily resolved and processing is complicated. By radiation peroxidation of the surface of polyethylene a simple polyethylene-metal laminate has been produced. Measurements of the mechanical properties and the electrical properties showed the laminating film conforms well with the national standards. It has been found that the adhesive strength of the polyethylene-metal film is affected by irradiation, the metal surface reactivity and cleaning of the laminating surface. Polyethylene-metal film laminated by radiation method is more heat resistant than the film laminated by conventional methods. The laminate materials can be widely used in electrical devices, chemical and packaging industry. (author)

188

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

189

Improved GLR method to instrument failure detection  

International Nuclear Information System (INIS)

The generalized likehood radio(GLR) method performs statistical tests on the innovations sequence of a Kalman-Buchy filter state estimator for system failure detection and its identification. However, the major drawback of the convensional GLR is to hypothesize particular failure type in each case. In this paper, a method to solve this drawback is proposed. The improved GLR method is applied to a PWR pressurizer and gives successful results in detection and identification of any failure. Furthmore, some benefit on the processing time per each cycle of failure detection and its identification can be accompanied. (Author)

190

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

191

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)

192

CURRENT METHODS FOR DETECTION OF CRYPTOSPORIDIUM SPECIES  

Science.gov (United States)

Current methods for detecting protozoa in water produce results that are highly variable. It is difficult to determine if the methods themselves, or the procedures for testing these methods, are the source of the variability. If testing procedures are responsible for high varia...

193

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

194

Developing methods for detecting radioactive scrap  

International Nuclear Information System (INIS)

During the last 10 years, there have been major developments in radiation detection systems used for catching shielded radioactive sources in scrap metal. The original testing required to determine the extent of the problem and the preliminary designs of the first instruments will be discussed. Present systems available today will be described listing their advantages and disadvantages. In conclusion, the newest developments and state of the art equipment will also be included describing the limits and most appropriate locations for the systems

195

Radiation shielding fiber and its manufacturing method  

International Nuclear Information System (INIS)

Purpose: To manufacture radiation shielding fibers of excellent shielding effects. Method: Fibers containing more than 1 mmol/g of carboxyl groups are bonded with heavy metals, or they are impregnated with an aqueous solution containing water-soluble heavy metal salts dissolved therein. Fibers as the substrate may be any of forms such as short fibers, long fibers, fiber tows, webs, threads, knitting or woven products, non-woven fabrics, etc. It is however necessary that fibers contain more than 1 mmol/g, preferably, from 2 to 7 mmol/g of carboxylic groups. Since heavy metals having radiation shielding performance are bonded to the outer layer of the fibers and the inherent performance of the fibers per se is possessed, excellent radiation shielding performance can be obtained, as well as they can be applied with spinning, knitting or weaving, stitching, etc. thus can be used for secondary fiber products such as clothings, caps, masks, curtains, carpets, cloths, etc. for use in radiation shieldings. (Kamimura, M.)

196

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

197

The EPR detection of radiation treated foodstuffs  

International Nuclear Information System (INIS)

The short paper by a Polish study group describes the results of the use of Electron Paramagnetic Resonance (EPR) Spectroscopy in the detection of irradiation to food. Pultry, fresh-water fish and sea fish as well as various fruits and yellow boletus are dealt with in some detail. (VHE)

198

Development of landmine detection system by using backscattering neutron method  

International Nuclear Information System (INIS)

Metal detector could not detect many kinds of Anti-Personal landmines which consist of plastic and explosive materials, for example TNT, RDX, etc, hence nuclear radiation detector, namely the gamma rays and neutron detectors, is prospect to be applied. One nuclear method for determining the landmine is measuring the backscattering neutron. The concept of radiation detection is detecting bulk material landmine which contains hydrogen, nitrogen, oxygen, and/or carbon by irradiating the soil with neutrons and detecting the gamma rays and neutron radiation that appears on the soil surface as a result from neutron-soil/target interaction. The development of landmine detection system has been proposed by using thermal backscattering neutron method. However, some difficulties are caused by the complexity of conditions, for example humidity, soil contents, density of each material of landmines and others. The purpose of this study is to setup a detection system with high efficiency for detecting the landmine by utilizing backscattering neutron method. Previously, the landmine detection experiment has been based on measuring the difference in the total counts of neutron in two cases, which are with and without melamine target. Nevertheless, a detection problem still remains in the case of deeply location target to the surface and humid cases due to the domination of hydrogen effect. In the present work, in order to detect as efficient as possible the existence of landmine insias possible the existence of landmine inside the soil, two methods are applied simultaneously. First, the total counts measurements are performed, and then the determination of epithermal and fast backscattering neutrons effect is measured by using the 3He detector with Cadmium covered. In order to obtain the dominant effect of hydrogen in all energy ranges, the total neutron count will be conducted firstly. The total neutron counts measurement is suitable when higher content hydrogen exist in the landmines rather than in the soil. The detection of carbon and nitrogen is also proposed to enhance the efficiency of the measurement based on its high elastic cross section. Therefore, the Monte Carlo simulation is performed to study the effect of C, N and H of the melamine when using targets such as C3H6N6, C3N6 and hydrogen. (author)

199

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)

200

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

201

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

202

On methods of detection of extraterrestrial life.  

Science.gov (United States)

New methods have been developed for detecting microbial growth from the microflora of desert soils. The first is a polarimetric method in which the fall in optical activity due to assimilation of D-glucose is followed. Detectable changes with desert soils were seen in a few hours, and the method can be employed with small amounts of material. The second method is the release of heat from metabolizable substrates as measured by a microcalorimeter. In the presence of glucose a characteristic response from desert soils was found within 24 hours. PMID:12678119

Imshenetsky, A A; Evdokimova, M D; Sotnikov, G G

1976-01-01

203

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

1987-01-01

204

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

205

Method of detecting nuclear fuel failures  

International Nuclear Information System (INIS)

Purpose: To improve the detection sensitivity and reliability of fuel failures in LMFBR type reactors. Constitution: In the fuel failure detection method, nuclear fuel failures are detected upon start-up or shutdown or during constant flow rate operation state at low power operation of a nuclear power plant. The nuclear fuel failures are detected by monitoring whether the ratio between the forecast balance for delayed neutron counting rate signal from the outside of coolant pipeways near the exit of a nuclear reactor to the reactor power is dependent on the coolant temperature or not and a result in proportion to the scale of nuclear fuel failures is outputted. In this way, slight failures that have not been detected during high power operation can be detected upon reactor shutdown operation. (Seki, T.)

206

Bremstrahlung Detection and Chamber Obstruction Localisation Using Scanning Radiation Detectors  

CERN Document Server

Radiation monitors consisting of scintillating plastic coupled to photomultipliers are used for diagnostic purposes. By scanning such a detector or a radiation scatterer, two applications are demonstrated: i) Monitoring of vacuum chamber conditioning by monitoring gas Bremstrahlung from residual gas. ii) Localisation of beam interception (beam losses) by longitudinal scanning of a radiation detector. The measurement of gas pressure inside long, small cross section, vacuum vessels is difficult due to the distance between the centre of the vacuum vessel and vacuum gauges (leading to a low vacuum conductance). The narrow beam of gamma Bremstrahlung radiation is intercepted by scanning tungsten blades in the beam line front-end allowing a radiation shower to be detected outside the vacuum vessel proportional to the gas pressure in the corresponding storage ring straight section. A second detector mounted on rails can be moved over a length of 6.5m parallel to the ESRF storage ring so as to localise regions of bea...

Naylor, G A; Robinson, D

2005-01-01

207

Monte Carlo method in radiation transport problems  

International Nuclear Information System (INIS)

In neutral radiation transport problems (neutrons, photons), two values are important: the flux in the phase space and the density of particles. To solve the problem with Monte Carlo method leads to, among other things, build a statistical process (called the play) and to provide a numerical value to a variable x (this attribution is called score). Sampling techniques are presented. Play biasing necessity is proved. A biased simulation is made. At last, the current developments (rewriting of programs for instance) are presented due to several reasons: two of them are the vectorial calculation apparition and the photon and neutron transport in vacancy media

208

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.)

209

Micronuclei: sensitivity for the detection of radiation induced damage  

International Nuclear Information System (INIS)

The in vitro cytokinesis-block (CB) micronucleus (MN) assay for human peripheral blood has been used extensively for the assessment of chromosomal damage induced by ionizing radiation and chemicals and considered a suitable biological dosimeter for estimating in vivo whole body exposures, particularly in the case of large scale radiation accidents. One of the major drawbacks of the MN assay is its reduced sensitivity for the detection of damage induced by low doses of low LET radiation, due to the high variability among the spontaneous MN frequencies. It is suggested that age, smoking habit and sex are the main confounding factors that contribute to the observed variability. Previous work in our laboratory, shows a significant positive correlation of the spontaneous and radiation induced MN frequencies with age and smoking habit, the latter being the strongest confounder. These findings led to in vitro studies of the dose-response relationships for smoking and non smoking donors evaluated separately, using 60Co ? rays. The objectives of the present work are: 1-To increase the amount of data of the dose-response relationships, using ? rays from a 60Co source, for smoking and non smoking donors, in order to find, if applicable, a correction factor for the calibration curve that takes into account the smoking habit of the individual in the case of accidental overexposure dose assessment, particularly in the low dose range. 2-To establish general conclusions on the current state of the technique. The sample for smoking and non smoking calibration curves was enlarged in the range of 0Gy to 2Gy. The fitting of both curves, performed up to the 2Gy dose, resulted in a linear quadratic model. MN distribution among bi nucleated cells was found to be over dispersed with respect to Poisson distribution, the average ratio of variance to mean being 1.13 for non smokers and 1.17 for smokers. Each fitted calibration curve, for smoking and non smoking donors, fell within the 95% confidence curves of the other, with the exception of the spontaneous frequency values of both calibration curves. Thus, for the accidental overexposure dose assessment it seems to be appropriate to use a pooled data (smokers + non smokers) calibration curve and in the case of dose assessment up to 0.5Gy, it is convenient to use the corresponding spontaneous term in the yield equation; associated to the individual smoking habit condition. General conclusions: 1-The high and variable spontaneous MN frequency prevents an adequate dose estimation below 0.2-0.3Gy of low LET radiation. 2-At high doses, of low LET radiation, the sensitivity of the MN test is lower than the conventional aberration methods (dicentrics) due to the smaller squared term in the yield equation. 3-Radiation induced MN tend to be over dispersed with respect to Poisson distribution. Over dispersion increases the standard error on the observed yield and thus the uncertainties on the dose estimation. (author)

210

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

211

Radiation detection technique on the fishery foods  

International Nuclear Information System (INIS)

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.)

212

Ground-level detection of auroral kilometric radiation  

Science.gov (United States)

The Earth's auroral electrons radiate up to ˜1% of their energy in radio waves, called Auroral Kilometric Radiation (AKR). The emission mechanism, called the electron cyclotron maser (ECM), produces similar emissions at other planets, in the solar atmosphere, and possibly in astrophysical systems such as pulsars and blazars. ECM theory applied to AKR predicts radiation beamed outward that cannot penetrate near the Earth. Nevertheless, over the past several decades there have been occasional reports of AKR-like signals detected at low altitudes. Here we show the first evidence that AKR does indeed penetrate to low altitudes. For three examples of AKR-like emissions detected at South Pole Station, Antarctica, we examined data from the Geotail satellite plasma wave receiver, which had a field of view that included the auroral field lines above the station. The AKR-like emissions detected at ground-level have the same frequency-time structure as simultaneous AKR emissions detected on Geotail 115,000-190,000 km away from the Earth. These first coincident detections of AKR in space and on the ground require the existence of a mechanism to produce the ground-level emissions, suggest that previous AKR-like emissions observed at low altitudes may indeed be AKR, and require revision of the widely-held textbook view that AKR is only detectable from space.

LaBelle, James; Anderson, Roger R.

2011-02-01

213

ITRAP. Illicit trafficking radiation detection assessment program  

International Nuclear Information System (INIS)

Illicit trafficking in nuclear materials (nuclear criminality) has become more and more a problem, due to the circulation of the a high number of radioactive sources and the big amount of nuclear material, particularly, caused by the changes of the organisational infrastructures to supervise these material within the successor states of the former Soviet Union. The IAEA data base counts at present more than 300 verified cases. The endangering cased thereby ranges from possible health defect for the publication to terrorists activities and production of nuclear weapons. In addition to the primary criminal reasons the illegal deposal of radioactive sources as salvage, scrap and others show a further problem, which has lead to severe accidents and lethal effects in the past (e.g. Goiana, Mexiko). As the study ITRAP (Illicit Trafficking Radiation Assessment Program) can show, also in Austria the cases of partly considerable contaminated scrap transports from neighbouring countries exists. Some countries have already under taken countermeasures (e.g. Monitoring at the Finnish-Russian and German-Polish border, border monitoring in Italy). The International Atomic Energy Agency (IAEA) has reacted on this actual problem by setting up a new program to fight against nuclear criminality and has suggested a pilot study for the practical test of border monitoring systems. Aim of the study was to work out the technical requirements and the practicability of an useful monitoring syspracticability of an useful monitoring system at border crossings. The results of the study will be offered by the IAEA to the member states as international recommendations for border monitoring systems. (author)

214

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

215

Characterization of mobile radiation detection systems at the Hanford Site  

International Nuclear Information System (INIS)

The use of vehicle-mounted radiation detection systems for characterizing large areas contaminated with radioactive materials at the Hanford Reservation were examined. Detection capabilities as a function of vehicle speed, detector-source geometry, and source characteristics were evaluated for each of the three systems currently used at the Hanford Site. Large-area radioactive sources (1 ft2) with varying source strengths containing gamma- and beta-emitting radionuclides were used to measure detection-system performance. Detection capability was found to be most influenced by vehicle speed and detector-source geometry. As the vehicle's speed was increased, the probability of detecting a given source decreased dramatically. The probability of detecting a given source was significantly lower under ''poor'' geometry conditions. Each vehicle's monitoring performance was found to compare favorably with portable survey instrument capabilities. The use of vehicle-mounted detectors proves to be far more economical for surveying large surface areas

216

Detecting Urinary Bladder Contractions: Methods and Devices  

Directory of Open Access Journals (Sweden)

Full Text Available In patients suffering from neurogenic detrusor overactivity, continence can be regained by conditional stimulation of the dorsal genital nerve (DGN; that is applying electrical stimulation to the DGN at the onset of an involuntary contraction. For this scheme to work, a sensor capable of reliably detecting the onset of bladder contractions is needed. This article reviews the methods proposed for or associated with detection of bladder contractions, and their applicability to onset detection is assessed. Fourteen methods are described in this review; bladder pressure, urethral sphincter EMG and anal sphincter EMG are the most promising options for onset detection. For all three modalities, however, further research is needed before clinical application becomes viable.

Jacob Melgaard

2014-10-01

217

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

218

Detection of radiation pressure acting on 2009 BD  

CERN Document Server

We report the direct detection of radiation pressure on the asteroid 2009 BD, one of the smallest multi-opposition near-Earth objects currently known, with H ~ 28.4. Under the purely gravitational model of NEODyS the object is currently considered a possible future impactor, with impact solutions starting in 2071. The detection of a radiation-related acceleration allows us to estimate an Area to Mass Ratio (AMR) for the object, that can be converted (under some assumptions) into a range of possible values for its average density. Our result AMR = (2.97 \\pm 0.33) x 10^(-4) m^2 kg^(-1) is compatible with the object being of natural origin, and it is narrow enough to exclude a man-made nature. The possible origin of this object, its future observability, and the importance of radiation pressure in the impact monitoring process, are also discussed.

Micheli, Marco; Elliott, Garrett T

2011-01-01

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

Control of irradiated food: recent developments in analytical detection methods  

International Nuclear Information System (INIS)

An overview of recent international efforts, i.e. programmes of ''ADMIT'' (FAO/IAEA) and of BCR (EC) towards the development of analytical detection methods for radiation processed food will be given. Some larger collaborative studies have already taken place, e.g. ESR of bones from chicken, pork, beef, frog legs and fish, thermoluminescence of insoluble minerals isolated from herbs and spices, GC analysis of long-chain hydrocarbons derived from the lipid fraction of chicken and other meats, and the microbiological APC/DEFT procedure for spices. These methods could soon be implemented in international standard protocols. (author)

221

Control of irradiated food: Recent developments in analytical detection methods.  

Science.gov (United States)

An overview of recent international efforts, i.e. programmes of "ADMIT" (FAO/IAEA) and of BCR (EC) towards the development of analytical detection methods for radiation processed foods will be given. Some larger collaborative studies have already taken place, e.g. ESR of bones from chicken, prok, beef, frog legs and fish, thermoluminescence of insoluble minerals isolated from herbs and spices, GC analysis of long-chain hydrocarbons derived from the lipid fraction of chicken and other meats, and the microbiological APC/DEFT procedure for spices. These methods could soon be implemented in international standard protocols.

Delincée, H.

1993-07-01

222

Detection of radiation of powerful fiber lasers reflected back from metals in course of laser processing  

International Nuclear Information System (INIS)

The method allowing to detect in real time the laser radiation reflected from metal in course of its processing by powerful fiber ytterbium lasers is proposed. It is shown that there is a correspondence between the behavior of a reflected back signal and the oscillatory processes in a liquid bath of the fused metal

223

Three Methods of Detection of Hydrazines  

Science.gov (United States)

Three proposed methods for measuring trace quantities of hydrazines involve ionization and detection of hydrazine derivatives. These methods are intended to overcome the limitations of prior hydrazine- detection methods. Hydrazine (Hz), monomethylhydrazine (MMH), and unsymmetrical dimethylhydrazine (UDMH) are hypergolic fuels and are highly reactive, toxic, and corrosive. A capability to measure concentrations of hydrazines is desirable for detecting leaks and ensuring safety in aerospace settings and in some industrial settings in which these compounds are used. One of the properties (high reactivity) that make it desirable to detect trace amounts of hydrazines also makes it difficult to detect hydrazines and measure their concentrations accurately using prior methods: significant amounts are lost to thermal and catalytic decomposition prior to detection. Further complications arise from the sticky nature of hydrazines: Sample hydrazine molecules tend to become irreversibly adsorbed onto solid surfaces with which they come into contact during transport to detectors, giving rise to drift in detector responses. In each proposed method, the reactive, sticky nature of hydrazines would be turned to advantage by providing a suitably doped substrate surface with which the hydrazines would react. The resulting hydrazine derivatives would be sufficiently less sticky and sufficiently more stable so that fewer molecules would be lost to decomposition or adsorption during transport. Consequently, it would be possible to measure concentration with more sensitivity and less error than in prior techniques. The first proposed method calls for the use of a recently developed technique known as desorption electrospray ionization (DESI), in which a pneumatically assisted micro -electrospray at ambient pressure is directed at a surface of interest. In this case, the surface of interest would be that of a substrate described above.

Griffin, Timothy; Berger, Cristina

2010-01-01

224

Multigrid Methods for Polarized Radiative Transfer  

CERN Document Server

A new iterative method for non-LTE multilevel polarized radiative transfer in hydrogen lines is presented. Iterative methods (such as the Jacobi method) tend to damp out high-frequency components of the error fast, but converges poorly due to slow reduction of low-frequency components. The idea is to use a set of differently coarsed grids to reduce both the short- and long-period errors. This leads to the so-called multigrid (MG) methods. For the grid of $N$ spatial points, the number of iterations required to solve a non-LTE transfer problem is of the order of O(N). This fact could be of great importance for problems with fine structure and for multi-dimensional models. The efficiency of the so-called standard MG iteration in comparison to Jacobi iteration is shown. The formalism of density matrix is applied to the demonstrative example of 1D, semi-infinite, non-magnetic, 3-principal level hydrogen atmospheric model. The effect of depolarizing collisions with thermal electrons is taken into account as well a...

Stepan, J

2006-01-01

225

Application of organic semiconductors for the detection of ionizing radiations  

International Nuclear Information System (INIS)

One year aged organic bilayer Al/PCTDA/CuPc/ITO structure prepared with ICB deposition method has been used to evaluate the influence of ionising radiation to electrical properties of the structure. Small sources of ?, ? and ? radiation were used for preliminary measurements. Capacitance and current measurements were performed on samples with and without presence of ionising radiation and results compared. Effect of ? and ? radiation has not been confirmed due to the limited activity of available sources. Presence of ? radiation has noticeably changed the capacitance of reversely biased structure and produced increase of current through the structure. We have tried to explain the capacitance properties using the model previously developed for the organic bilayer structures, but we did not manage to resolve all effects involved. (author)

226

Novel methods for detecting buried explosive devices  

Energy Technology Data Exchange (ETDEWEB)

Oak Ridge National Laboratory (ORNL) and Quantum Magnetics, Inc. (QM) are exploring novel landmine detection technologies. Technologies considered here include bioreporter bacteria, swept acoustic resonance, nuclear quadrupole resonance (NQR), and semiotic data fusion. Bioreporter bacteria look promising for third-world humanitarian applications; they are inexpensive, and deployment does not require high-tech methods. Swept acoustic resonance may be a useful adjunct to magnetometers in humanitarian demining. For military demining, NQR is a promising method for detecting explosive substances; of 50,000 substances that have been tested, none has an NQR signature that can be mistaken for RDX or TNT. For both military and commercial demining, sensor fusion entails two daunting tasks, identifying fusible features in both present-day and emerging technologies, and devising a fusion algorithm that runs in real-time on cheap hardware. Preliminary research in these areas is encouraging. A bioreporter bacterium for TNT detection is under development. Investigation has just started in swept acoustic resonance as an approach to a cheap mine detector for humanitarian use. Real-time wavelet processing appears to be a key to extending NQR bomb detection into mine detection, including TNT-based mines. Recent discoveries in semiotics may be the breakthrough that will lead to a robust fused detection scheme.

Kercel, S.W.; Burlage, R.S.; Patek, D.R.; Smith, C.M. [Oak Ridge National Lab., TN (United States); Hibbs, A.D.; Rayner, T.J. [Quantum Magnetics, Inc., San Diego, CA (United States)

1997-04-01

227

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

228

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

229

Modified chemical methods applied for radiation dosimetry  

International Nuclear Information System (INIS)

Two chemical methods were studied for radiation dosimetry: the Fricke ferrous sulfate dosimeter, for reference purposes, and the ceric sulfate dosimeter, for routine dosimetric work. In the case of Fricke dosimeter, its main parameters were determined: the wavelength of maximum absorption for the Fe2+ ions, the molar extinction coefficient and the calibration curves as a function of the Fe2+ ions initial concentration. The dose rate determinations were made using ortho-phenanthroline, that acts as a complexant. This dosimeter was used for the dose rate mapping of a 60 Co (185 Tbq) source radiation field, at the irradiation table plane. The ceric sulfate dosimeter was chosen from several possible chemical dosimeters because of its properties as simple preparation, low cost and chemical reagents available at the laboratory. In this work this dosimeter was modified with respect to the use of sodium oxalate instead of arsenic oxide conventionally used for its standardization, in order to minimize its preparation cost. In this case the wavelength for maximum absorption for the Ce4+ ions and calibration curves in function of the Ce4+ ions initial concentration and of the absorbed dose in the dosimeter were determined. The obtained results showed the feasibility of use of this dosimeter between 0,25 and 10 KGy, depending on the initial concentration of Ce4+ ions. (author). 34 refs., 8 figs., 17 tabsor). 34 refs., 8 figs., 17 tabs

230

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 global level is needed...

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

2008-01-01

231

Ultrafast Radiation Detection by Modulation of an Optical Probe Beam  

International Nuclear Information System (INIS)

We describe a new class of radiation sensor that utilizes optical interferometry to measure radiation-induced changes in the optical refractive index of a semiconductor sensor medium. Radiation absorption in the sensor material produces a transient, non-equilibrium, electron-hole pair distribution that locally modifies the complex, optical refractive index of the sensor medium. Changes in the real (imaginary) part of the local refractive index produce a differential phase shift (absorption) of an optical probe used to interrogate the sensor material. In contrast to conventional radiation detectors where signal levels are proportional to the incident energy, signal levels in these optical sensors are proportional to the incident radiation energy flux. This allows for reduction of the sensor form factor with no degradation in detection sensitivity. Furthermore, since the radiation induced, non-equilibrium electron-hole pair distribution is effectively measured ''in place'' there is no requirement to spatially separate and collect the generated charges; consequently, the sensor risetime is of the order of the hot-electron thermalization time (le) 10 fs and the duration of the index perturbation is determined by the carrier recombination time which is of order ? 600 fs in, direct-bandgap semiconductors, with a high density of recombination defects; consequently, the optical sensors can be engineered with sub-ps temporal response. A series of detectors were designed, andA series of detectors were designed, and incorporated into Mach Zehnder and Fabry-Perot interferometer-based detection systems: proof of concept, lower detection sensitivity, Mach-Zehnder detectors were characterized at beamline 6.3 at SSRL; three generations of high sensitivity single element and imaging Fabry-Perot detectors were measured at the LLNL Europa facility. Our results indicate that this technology can be used to provide x-ray detectors and x-ray imaging systems with single x-ray sensitivity and S/N ? 30 at x-ray energies ? 10 keV

232

Ultrafast Radiation Detection by Modulation of an Optical Probe Beam  

Energy Technology Data Exchange (ETDEWEB)

We describe a new class of radiation sensor that utilizes optical interferometry to measure radiation-induced changes in the optical refractive index of a semiconductor sensor medium. Radiation absorption in the sensor material produces a transient, non-equilibrium, electron-hole pair distribution that locally modifies the complex, optical refractive index of the sensor medium. Changes in the real (imaginary) part of the local refractive index produce a differential phase shift (absorption) of an optical probe used to interrogate the sensor material. In contrast to conventional radiation detectors where signal levels are proportional to the incident energy, signal levels in these optical sensors are proportional to the incident radiation energy flux. This allows for reduction of the sensor form factor with no degradation in detection sensitivity. Furthermore, since the radiation induced, non-equilibrium electron-hole pair distribution is effectively measured ''in place'' there is no requirement to spatially separate and collect the generated charges; consequently, the sensor risetime is of the order of the hot-electron thermalization time {le} 10 fs and the duration of the index perturbation is determined by the carrier recombination time which is of order {approx} 600 fs in, direct-bandgap semiconductors, with a high density of recombination defects; consequently, the optical sensors can be engineered with sub-ps temporal response. A series of detectors were designed, and incorporated into Mach Zehnder and Fabry-Perot interferometer-based detection systems: proof of concept, lower detection sensitivity, Mach-Zehnder detectors were characterized at beamline 6.3 at SSRL; three generations of high sensitivity single element and imaging Fabry-Perot detectors were measured at the LLNL Europa facility. Our results indicate that this technology can be used to provide x-ray detectors and x-ray imaging systems with single x-ray sensitivity and S/N {approx} 30 at x-ray energies {approx} 10 keV.

Vernon, S P; Lowry, M E

2006-02-22

233

Detecting low gamma radiation doses using silica glass luminescence  

International Nuclear Information System (INIS)

This study investigates the spectroscopic characteristics of the radiation in the reactor and of the ?-course 60Co silica glasses produced by industry. The purpose of this investigation is the determination of the growth kinetics of radiation damage, stability, dependence on radiation mode, irradiation conditions and the possible use of glass in compound fields of reactors in 1015-1020 cm-2 range and absorbed dose of the photon from 100-106 Gy. Three types of glass were studied and the optical registering methods have been chosen (the photoluminescence and optical absorption spectra were measured before and after irradiation)

234

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

235

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

236

Proceedings of the fourth international symposium on radiation safety and detection technology  

International Nuclear Information System (INIS)

This issue is the collection of the paper presented at the title symposium. The symposium has the following six topics: radiation transport and shielding, radiation dosimetry, radiation detection and sensor technology, environmental radiation measurements and assessments, radiation risk management and radiation protection philosophy and policy. The 194 of the presented papers are indexed individually. (J.P.N.)

237

Current trends in gamma radiation detection for radiological emergency response  

Science.gov (United States)

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 inter-disciplinary 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, Sanjoy; Guss, Paul; Maurer, Richard

2011-09-01

238

Soft X radiation spectrograph with charge-coupled detection  

International Nuclear Information System (INIS)

Soft X radiation spectrograph (0.8-4 keV) with charge-coupled detection (CCD) is described. The CCD characteristics in quanta energy roentgen range are presented. The spectrograph is applied for spectroscopy of plasma radiation of heavy-current Z-pinches. The analogous signal from the CCD after amplitude-digital conversion is inputted into the computer. Application of special algorithm for processing obtained spectra makes it possible to determine effectively the plasma parameters: electron temperature and density. 12 refs., 8 figs

239

Flexible Receiver Radiation Detection System (FRRDS) Users Manual  

International Nuclear Information System (INIS)

The Flexible Receiver Radiation Detection System (FRRDS) comprises a control computer, a remote data acquisition subsystem, and three hyperpure germanium gamma radiation detectors. The scope of this document is the description of various steps for the orderly start-up, use, and shutdown of the FRRDS. Only those items necessary for these oprations are included. This document is a companion to WHC-SD-W151-UM-002, 'Operating Instructions for the 42 Inch Flexible Receiver,' WHC-SD-W151-UM-003, 'Operating Instructions for the 4-6 Inch Flexible Receiver,' and the vendor supplied system users guide (Ref. 6)

240

Consistent energy treatment for radiation transport methods  

Science.gov (United States)

The approximations used in the standard multigroup method and cross section condensation procedure introduce several known errors, such those caused by spectral core environment effects and the neglect of the energy and angular coupling of the flux when condensing the total cross section. In this dissertation, a multigroup formulation is developed which maintains direct consistency with the continuous energy or fine-group structure, exhibiting the accuracy of the detailed energy spectrum within the coarse-group calculation. Two methods are then developed which seek to invert the condensation process -- turning the standard one-way condensation (from fine-group to coarse-group) into the first step of a two-way iterative process. The first method is based on the previously published Generalized Energy Condensation, which established a framework for obtaining the finegroup flux by preserving the flux energy spectrum in orthogonal energy expansion functions, but did not maintain a consistent coarse-group formulation. It is demonstrated that with a consistent extension of the GEC, a cross section recondensation scheme can be used to correct for the spectral core environment error. This is then verified numerically in a 1D VHTR core. In addition, a more practical and efficient new method, termed the "Subgroup Decomposition (SGD) Method," is developed which eliminates the need for expansion functions altogether, and allows the fine-group flux to be decomposed from a consistent coarse-group flux with minimal additional computation or memory requirements. This method, as a special case of a more general spline-approximation for radiation transport, is shown to be highly effective in a cross section recondensation scheme, providing fine-group results in a fraction of the time generally necessary to obtain a fine-group solution. In addition, a whole-core BWR benchmark problem is generated based on operating reactor parameters, in 2D and 3D. This contributes to the furthering of new methods development from the proof-of-concept level to the whole-core direct 3D transport level . A set of 1D benchmarks is also developed for a BWR, PWR, and VHTR core. These provide significant value both in preliminary testing of the new methods presented in this dissertation and in the future testing of new transport methods.

Douglass, Steven James

241

Noise Radiation Measure-Sound Power and its Test Methods  

Directory of Open Access Journals (Sweden)

Full Text Available 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

2013-06-01

242

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

243

Development of automatic analyzing system for radiation-induced mutation. Improvement of its detection efficacy and developments of effective probe and primer, and detection techniques  

International Nuclear Information System (INIS)

From the previous project on high-speed autoanalyzing system for radiation-induced chromosome aberrations, it became possible to easily and certainly identify a centromere by fluorescence staining according to FISH method using a probe with the consensus sequence to ?-satellite DNA. However, this method was thought to be unappropriate for the analysis of dicentric chromosomes because the amount of the satellite DNA on the centromeres was in a wide range, 1-4%. Therefore, development of the detection method for radiation-induced mutation using a new fluorescent material was attempted in this study. First, a detection method using PCR for different genes was developed and a new method for purification of genome DNA from culture cells only with heat treatment was established. Then, real-time detection of genome DNA damaged by radiation was attempted. (M.N.)

244

Researchers develop four new radiation control methods  

International Nuclear Information System (INIS)

The author describes exploratory research into radiation transport processes which has resulted in four new products to help utilities reduce radiation exposure in nuclear power plants. According to the author, chemical decontamination, elevated pH chemistry, zinc passivation, and cobalt-free hardfacing alloys can reduce radiation fields. These four processes are discussed in this paper

245

Method and system for detecting an explosive  

Science.gov (United States)

A method and system for detecting at least one explosive in a vehicle using a neutron generator and a plurality of NaI detectors. Spectra read from the detectors is calibrated by performing Gaussian peak fitting to define peak regions, locating a Na peak and an annihilation peak doublet, assigning a predetermined energy level to one peak in the doublet, and predicting a hydrogen peak location based on a location of at least one peak of the doublet. The spectra are gain shifted to a common calibration, summed for respective groups of NaI detectors, and nitrogen detection analysis performed on the summed spectra for each group.

Reber, Edward L. (Idaho Falls, ID); Rohde, Kenneth W. (Idaho Falls, ID); Blackwood, Larry G. (Bozeman, MT)

2010-12-07

246

A method for characterizing photon radiation fields  

International Nuclear Information System (INIS)

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

247

Infrared luminescence for real time ionizing radiation detection  

Energy Technology Data Exchange (ETDEWEB)

Radio-luminescence (RL) optical fiber sensors enable a remote, punctual, and real time detection of ionizing radiation. However, the employment of such systems for monitoring extended radiation fields with energies above the Cerenkov threshold is still challenging, since a spurious luminescence, namely, the “stem effect,” is also generated in the passive fiber portion exposed to radiation. Here, we present experimental measurements on Yb-doped silica optical fibers irradiated with photon fields of different energies and sizes. The results demonstrate that the RL of Yb{sup 3+}, displaying a sharp emission line at about 975?nm, is free from any spectral superposition with the spurious luminescence. This aspect, in addition with the suitable linearity, reproducibility, and sensitivity properties of the Yb-doped fibers, paves the way to their use in applications where an efficient stem effect removal is required.

Veronese, Ivan, E-mail: ivan.veronese@unimi.it; Mattia, Cristina De; Cantone, Marie Claire [Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, 20133 Milano (Italy); Fasoli, Mauro; Chiodini, Norberto; Vedda, Anna [Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, Via Cozzi 55, 20125 Milano (Italy); Mones, Eleonora [Medical Physics Department, Azienda Ospedaliera Maggiore della Carità, Corso Mazzini 18, 28100 Novara (Italy)

2014-08-11

248

Infrared luminescence for real time ionizing radiation detection  

Science.gov (United States)

Radio-luminescence (RL) optical fiber sensors enable a remote, punctual, and real time detection of ionizing radiation. However, the employment of such systems for monitoring extended radiation fields with energies above the Cerenkov threshold is still challenging, since a spurious luminescence, namely, the "stem effect," is also generated in the passive fiber portion exposed to radiation. Here, we present experimental measurements on Yb-doped silica optical fibers irradiated with photon fields of different energies and sizes. The results demonstrate that the RL of Yb3+, displaying a sharp emission line at about 975 nm, is free from any spectral superposition with the spurious luminescence. This aspect, in addition with the suitable linearity, reproducibility, and sensitivity properties of the Yb-doped fibers, paves the way to their use in applications where an efficient stem effect removal is required.

Veronese, Ivan; Mattia, Cristina De; Fasoli, Mauro; Chiodini, Norberto; Mones, Eleonora; Cantone, Marie Claire; Vedda, Anna

2014-08-01

249

Radiation detection using the color changes of lilac spodumene  

International Nuclear Information System (INIS)

The use of radiation in industrial processes currently offers several advantages in the field of sterilization of medical and pharmaceuticals products, the preservation of food, and a variety of other products widely used in modern society. A dosimetry of confidence is a key parameter for the quality assurance of radiation processing and the irradiated products. This work investigates dosimetric properties in natural spodumene, LiAlSi2O6, called kunzite, from Minas Gerais State, Brazil. After X irradiation on the samples in powder form was detected a change in color of the crystal where the dose received. This makes a possible viability of this material is applied in research on development of radiation detectors using the change in color of purple spodumene. (author)

250

Infrared luminescence for real time ionizing radiation detection  

International Nuclear Information System (INIS)

Radio-luminescence (RL) optical fiber sensors enable a remote, punctual, and real time detection of ionizing radiation. However, the employment of such systems for monitoring extended radiation fields with energies above the Cerenkov threshold is still challenging, since a spurious luminescence, namely, the “stem effect,” is also generated in the passive fiber portion exposed to radiation. Here, we present experimental measurements on Yb-doped silica optical fibers irradiated with photon fields of different energies and sizes. The results demonstrate that the RL of Yb3+, displaying a sharp emission line at about 975?nm, is free from any spectral superposition with the spurious luminescence. This aspect, in addition with the suitable linearity, reproducibility, and sensitivity properties of the Yb-doped fibers, paves the way to their use in applications where an efficient stem effect removal is required

251

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

252

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 ?m(2)) spectroscopic Timepix detector adapted for neutron detection utilizing very thin (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(-4). PMID:24517756

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

2014-01-01

253

Radiation Detection System for Prevention of Radiological and Nuclear Terrorism  

International Nuclear Information System (INIS)

After the September 11 terrorist attack, the threat of a potential for a radiological or nuclear terrorist attack became more apparent. The threats relating to radiological or nuclear materials include a Radiological Dispersion Device (RDD), an Improved Nuclear Device (IND) or a State Nuclear Device (such as a Soviet manufactured suitcase nuclear weapon). For more effective countermeasures against the disaster, multilayer protection concept - prevention of smuggling of radioactive or nuclear material into our country through seaports or airports, detection and prevention of the threat materials in transit on a road, and prevention of their entry into a target building - is recommended. Due to different surrounding circumstances of where detection system is deployed, different types of radiation detection systems are required. There have been no studies on characteristics of detection equipment required under Korean specific conditions. This paper provides information on technical requirements of radiation detection system to achieve multi-layer countermeasures for the purpose of protecting the public and environment against radiological and nuclear terrorism

254

Radiation Detection System for Prevention of Radiological and Nuclear Terrorism  

Energy Technology Data Exchange (ETDEWEB)

After the September 11 terrorist attack, the threat of a potential for a radiological or nuclear terrorist attack became more apparent. The threats relating to radiological or nuclear materials include a Radiological Dispersion Device (RDD), an Improved Nuclear Device (IND) or a State Nuclear Device (such as a Soviet manufactured suitcase nuclear weapon). For more effective countermeasures against the disaster, multilayer protection concept - prevention of smuggling of radioactive or nuclear material into our country through seaports or airports, detection and prevention of the threat materials in transit on a road, and prevention of their entry into a target building - is recommended. Due to different surrounding circumstances of where detection system is deployed, different types of radiation detection systems are required. There have been no studies on characteristics of detection equipment required under Korean specific conditions. This paper provides information on technical requirements of radiation detection system to achieve multi-layer countermeasures for the purpose of protecting the public and environment against radiological and nuclear terrorism.

Kwak, Sung-Woo; Yoo, Ho-Sik; Jang, Sung-Sun; Kim, Jae-Kwang; Kim, Jung-Soo [Korea Institute of Nuclear Nonproliferation and Control, Daejeon (Korea, Republic of)

2007-07-01

255

A testing and calibration method for channel vehicle radiation monitoring system  

International Nuclear Information System (INIS)

In this paper, a testing and calibration method for channel vehicle radiation monitoring system was presented through experiments on the basisi of the requirements of IAEA technical guidance. The comprehensive performance for channel vehicle radiation monitoring system was studied in aspects of detection threshold, average value of activity response, nonlinearity of activity response, effective detection area and repeatability, and simultaneously, a method for dynamic testing was discussed. The result indicates that the testing and calibration method are feasible, and that there are practical significance for effective preventing the spread of radioactive materials due to monitor system's inaccuracy and malfunction. (authors)

256

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

257

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.

258

A novel method for detection of apoptosis  

Energy Technology Data Exchange (ETDEWEB)

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.

Zagariya, Alexander M., E-mail: zagariya@uic.edu

2012-04-15

259

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.

260

Development of detection methods for irradiated foods  

Energy Technology Data Exchange (ETDEWEB)

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.

Yang, Jae Seung; Kim, Chong Ki; Lee, Hae Jung [Korea Atomic Energy Research Insitiute, Taejon (Korea, Republic of); Kim, Kyong Su [Chosun University, Kwangju (Korea, Republic of)

1999-04-01

261

Hough transform methods used for object detection  

International Nuclear Information System (INIS)

The Hough transform (HT) is a robust parameter estimator of multi-dimensional features in images. The HT is an established technique which evidences a shape by mapping image edge points into a parameter space. The HT is technique which is used to isolate curves of a give shape in an image. The classical HT requires that the curve be specified in some parametric from and, hence is most commonly used in the detection of regular curves. The HT has been generalized so that it is capable of detecting arbitrary curved shapes. The main advantage of this transform technique is that it is very tolerant of gaps in the actual object boundaries the classical HT for the detection of line , we will indicate how it can be applied to the detection of arbitrary shapes. Sometimes the straight line HT is efficient enough to detect features such as artificial curves. The HT is an established technique for extracting geometric shapes based on the duality definition of the points on a curve and their parameters. This technique has been developed for extracting simple geometric shapes such as lines, circles and ellipses as well as arbitrary shapes. The HT provides robustness against discontinuous or missing features, points or edges are mapped into a partitioned parameter of Hough space as individual votes where peaks denote the feature of interest represented in a non-analytically tabular form. The main drawback of the HT technique is the computational requirement which has an exponential onal requirement which has an exponential growth of memory space and processing time as the number of parameters used to represent a primitive increases. For this reason most of the research on the HT has focused on reducing the computational burden for extracting of arbitrary shapes under more general transformations include a overview of describing the methods for the detection image processing programs are frequently required to detect and particle classification in an industrial setting, a standard algorithms for this detection lines, circles, and ellipses shapes in image by using the HT. The methods and algorithms working to detect the objects, in which captured from 3-dimension real image to 2-dimension image. (Author)

262

Noninvasive detection of weapons of mass destruction using terahertz radiation  

Science.gov (United States)

The growing and immediate threat of biological and chemical weapons has placed urgency on the development of chemical and biological warfare agent (CWA/BWA) screening devices. Specifically, the ability to detect CWA/BWA prior to deployment is paramount to mitigating the threat without exposing individuals to its effects. SPARTA, Inc. and NIST are currently investigating the feasibility of using far-infrared radiation, or terahertz (THz, 1 THz = 1012 Hz) radiation, to non-invasively detect biological and chemical agents, explosives and drugs/narcotics inside sealed containers. Small-to-medium sized molecules (3-100 atoms) in gas, liquid and solid phases consistently exhibit identifiable spectral features in the far-IR portion of the spectrum. Many compounds associated with weapons of mass destruction are made up of molecules of this size. The THz portion of the spectrum lies between visible light and radio waves, allowing for partial transmission of 0.3-10.0 THz (30-1000 ?m, 10-330 cm-1) light through most common materials. Therefore, transmission measurements of THz light can potentially be used to non-invasively detect the presence of CWA/BWA, explosives and drugs in the pathway of a THz radiation beam.

Campbell, Matthew B.; Heilweil, Edwin J.

2003-08-01

263

Application of FISH method in evaluation of a radiation accident  

International Nuclear Information System (INIS)

To study effects of long term radiation hazard and explore the possibility of the application of chromosome aberration and FISH method to dose retrospection and reconstruction, FISH method was used to detect biological destination of three accidental victims at 7.5 years after Xinzhou accident. In the meantime, conventional chromosomal aberration, G-banding, CB micronuclei and HPRT gene locus mutation assays were performed. In addition, the growth and development of Victim S, who suffered the radiation accident as a fetus, were examined. And comparison of dose estimations between chromosome aberration and FISH method of the victims was conducted. The results demonstrated that the biological dose estimated by translocation frequency is very close to the imitated dose by the physical way after the accident if enough cells are observed. It is suggested that FISH may be applied to dose retrospection and reconstruction. Obvious chromosomal aberrations still existed in the examined victims at 7.5 years after the accident and displayed good dose correlative dependence. The results also showed that the growth and development of S were basically normal after birth

264

Nanotunneling Junction-based Hyperspectal Polarimetric Photodetector and Detection Method  

Science.gov (United States)

A photodetector, detector array, and method of operation thereof in which nanojunctions are formed by crossing layers of nanowires. The crossing nanowires are separated by a few nm thick electrical barrier layer which allows tunneling. Each nanojunction is coupled to a slot antenna for efficient and frequency-selective coupling to photo signals. The nanojunctions formed at the intersection of the crossing wires defines a vertical tunneling diode that rectifies the AC signal from a coupled antenna and generates a DC signal suitable for reforming a video image. The nanojunction sensor allows multi/hyper spectral imaging of radiation within a spectral band ranging from terahertz to visible light, and including infrared (IR) radiation. This new detection approach also offers unprecedented speed, sensitivity and fidelity at room temperature.

Son, Kyung-ah (Inventor); Moon, Jeongsun J. (Inventor); Chattopadhyay, Goutam (Inventor); Liao, Anna (Inventor); Ting, David (Inventor)

2009-01-01

265

Multiple-radiation detector: Detection of X-rays containing two energy values  

International Nuclear Information System (INIS)

A patent is claimed for the invention of a scintillation counter, able to detect radiations containing different energies. The invention can be applied to radiological devices. Two different materials are used: one of the chosen materials detects high energy radiation (green radiation) and the other one low energy radiations (red radiation). Filters are used for selecting such radiations before they reach the photodiodes. The design and the operation characteristics are described

266

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

267

Survey and evaluation of environmental radiation impact from industrial ?-ray defect detecting machine  

International Nuclear Information System (INIS)

This article first described the defect detecting machine in ways of working principle, relevant standards, environmental impact of radiation, then analysed the radiation affecting range and dose rate of a ?-ray detecting machine to environment radiation with measured data, finally proposes some safety management and radiation protection measurement. (authors)

268

Detection and spectral measurements of coherent synchrotron radiation at FLASH  

International Nuclear Information System (INIS)

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 ?m to 110 ?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 ?m to 160 ?m were done. (orig.)

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

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

273

Methods of detecting defective nuclear fuel elements  

International Nuclear Information System (INIS)

A method is specified for ultrasonically detecting defective nuclear fuel elements while under water and spaced within a nuclear fuel assembly of the type used in water cooled reactors. The method consists of inserting an ultrasonic search unit having an ultrasonic transducer element into the spaces between the fuel elements; aligning the transducer element with a fuel element to be examined; energising the transducer element to transmit an ultrasonic pulse into the fuel element to be examined; and measuring the ultrasonic echoes reflected. (author)

274

Application of a thermoluminescence method for detection of irradiated spices  

International Nuclear Information System (INIS)

Food irradiation is extremely effective at reducing food-borne illness as well as losses caused by infestation and contamination. Despite the well-established regulations that permit irradiation to control pathogens in spices, there are no widespread methods to detect previously irradiated food. Therefore, it has become necessary to develop new detection and dose determination methods for food subjected previously to irradiation. The present work deals with the application of the thermoluminescence (TL) phenomenon to detect irradiated spices. The process is based upon the thermoluminescence properties exhibited by the polymineral content of the irradiated specimen. After separating the organic material, it is possible to extract some polymineral substances that are suitable for thermoluminescence analysis due to interaction of the spice to ionising radiation. The method was successfully applied to examine irradiated and non-irradiated paprika of Mexican origin. The spice was irradiated with gamma rays at doses of 5, 10 and 15 kGy. The separated thermoluminescent polymineral was found to be composed mainly of quartz and feldspar. The thermoluminescence glow curve of the irradiated specimen shows a side band peaked 228, 268 and 336 deg. C, resembling pretty much the combined TL of quartz and feldspars. The method allows for the determination of the retrospective dose exposure. (author)

275

Application of a thermoluminescence method for detection of irradiated spices  

Energy Technology Data Exchange (ETDEWEB)

Food irradiation is extremely effective at reducing food-borne illness as well as losses caused by infestation and contamination. Despite the well-established regulations that permit irradiation to control pathogens in spices, there are no widespread methods to detect previously irradiated food. Therefore, it has become necessary to develop new detection and dose determination methods for food subjected previously to irradiation. The present work deals with the application of the thermoluminescence (TL) phenomenon to detect irradiated spices. The process is based upon the thermoluminescence properties exhibited by the polymineral content of the irradiated specimen. After separating the organic material, it is possible to extract some polymineral substances that are suitable for thermoluminescence analysis due to interaction of the spice to ionising radiation. The method was successfully applied to examine irradiated and non-irradiated paprika of Mexican origin. The spice was irradiated with gamma rays at doses of 5, 10 and 15 kGy. The separated thermoluminescent polymineral was found to be composed mainly of quartz and feldspar. The thermoluminescence glow curve of the irradiated specimen shows a side band peaked 228, 268 and 336 deg. C, resembling pretty much the combined TL of quartz and feldspars. The method allows for the determination of the retrospective dose exposure. (author)

Gastelum, S.; Osuna, I.; Melendrez, R.; Cruz-Zaragoza, E.; Chernov, V.; Calderon, T.; Barboza-Flores, M

2002-07-01

276

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

277

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

278

Fast neutron detection with silicon carbide semiconductor radiation detectors  

International Nuclear Information System (INIS)

Silicon carbide (SiC) radiation detectors are being developed for high-temperature applications in harsh radiation environments. Among these applications are characterization of nuclear reactor fuel and detection of concealed fissionable materials, which both require the optimization of SiC fast neutron detectors for detection and quantification of fission neutrons. In order to enhance fast-neutron sensitivity, proton recoil techniques are being used. Fission neutrons were simulated by using a 2.5-MeV deuterium-deuterium (D-D) neutron generator. In order to optimize the neutron detection sensitivity, 2.5-MeV neutron proton-recoil response measurements were made as a function of polyethylene converter layer thickness. Measurements were also made of the sensitivity of the SiC proton recoil detector as a function of angle of incidence of the neutrons. As expected from the angular sensitivity of the detector response, detection of neutrons normally incident to the detector face is favored allowing discrimination of background neutrons and possibly supplying information on the fissionable material location or configuration

279

Method of measuring blood flow by radiation  

International Nuclear Information System (INIS)

A method of measuring relative blood flow through at least a part of the body using penetrating radiation comprises transmitting a plurality of rays at an initial angle or initial mean angle through a planar slice of the body to define a first set of rays, transmitting a plurality of further sets of rays at angles or mean angles different from each other and from the initial angle or initial mean angle through the same planar slice of the body to define by the intersection of all such rays a two-dimensional matrix of elements of the body in the slice, measuring for each ray emerging from the body a number of over the period of time at least equal to a pulse interval representing the momentary sum of the transmissions or absorptions of the element of the body intersected by the ray, determining from the momentary signals momentary signals a difference signal representing the maximum difference between the momentary signals for each ray over the period of time, deriving sets of discrete difference signals corresponding to the sets of rays, the difference signals being indicative of the transmission or absorption of blood flowing through each element of the body in the matrix, and calculating from the difference signals resultant signals representing the transmissions or absorptions due to blood flow in the elements of the matrix. These resultant signals may be visually depicted on a cathode ray tube display, as a digital print-out, or as a photograph. 30 claims, 8 figures

280

Compact endocavity diagnostic probes for nuclear radiation detection  

Science.gov (United States)

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

281

A wave based method for computing high-frequency radiation  

OpenAIRE

The calculation of high-frequency wave radiations in exterior domains by finite element methods can lead to large computations. Boundary conditions have to be applied on the surface of the radiating body or on a truncated domain to approximate the behaviour of an infinite domain. In this paper, a different waveguide approach is proposed for computing wave radiation. Propagation constants and wave modes are computed in a small rib around the radiating body for different frequencies. It is show...

Duhamel, Denis

2011-01-01

282

Design of a Mobile Radiation Detection System for Seaports  

International Nuclear Information System (INIS)

Pacific Northwest National Laboratory (PNNL) has developed a mobile radiation detection system for the U.S. Customs department. Based on the radiation detection instruments currently in use at many border crossings, the mobile radiation portal monitor (mRPM) consists of two Ludlum 4500-3000 detector panels, a package of sensors and a sensor integration module mounted to a medium duty truck chassis. The sensor package detects the presence of scanning targets (containers) and uses this to control operation of the detectors. The mRPM is designed to scan containerized cargo at seaports. A single mRPM can be driven past grounded or chassis-mounted containers (both sides of the container must be scanned for complete coverage), or a pair of mRPM systems can be parked opposite one another to form a relocatable portal. This rapidly reconfigurable system has proven to be very useful for targeted scanning of containers at multiple seaports. Since seaports are frequently space-constrained and contain few chokepoints, mobile systems that can be easily relocated allow customs operators to effectively scan cargo with minimal interference with the flow of commerce. Operators previously trained in the use of the stationary radiation portal monitors require minimal additional training to use the mRPM systems. The medium duty trucks employed are similar to one-ton crew cab pickup trucks, and a commercial driver's license is not required to operate them. In addition to successful deploymte them. In addition to successful deployments at seaports, the mRPM units have proven useful in other applications, such as preliminary characterization of rail cargo and targeted scanning at special events (political conventions)

283

A dual-sided coded-aperture radiation detection system  

Science.gov (United States)

We report the development of a large-area, mobile, coded-aperture radiation imaging system for localizing compact radioactive sources in three dimensions while rejecting distributed background. The 3D Stand-Off Radiation Detection System (SORDS-3D) has been tested at speeds up to 95 km/h and has detected and located sources in the millicurie range at distances of over 100 m. Radiation data are imaged to a geospatially mapped world grid with a nominal 1.25- to 2.5-m pixel pitch at distances out to 120 m on either side of the platform. Source elevation is also extracted. Imaged radiation alarms are superimposed on a side-facing video log that can be played back for direct localization of sources in buildings in urban environments. The system utilizes a 37-element array of 5×5×50 cm 3 cesium-iodide (sodium) detectors. Scintillation light is collected by a pair of photomultiplier tubes placed at either end of each detector, with the detectors achieving an energy resolution of 6.15% FWHM (662 keV) and a position resolution along their length of 5 cm FWHM. The imaging system generates a dual-sided two-dimensional image allowing users to efficiently survey a large area. Imaged radiation data and raw spectra are forwarded to the RadioNuclide Analysis Kit (RNAK), developed by our collaborators, for isotope ID. An intuitive real-time display aids users in performing searches. Detector calibration is dynamically maintained by monitoring the potassium-40 peak and digitally adjusting individual detector gains. We have recently realized improvements, both in isotope identification and in distinguishing compact sources from background, through the installation of optimal-filter reconstruction kernels.

Penny, R. D.; Hood, W. E.; Polichar, R. M.; Cardone, F. H.; Chavez, L. G.; Grubbs, S. G.; Huntley, B. P.; Kuharski, R. A.; Shyffer, R. T.; Fabris, L.; Ziock, K. P.; Labov, S. E.; Nelson, K.

2011-10-01

284

Detection of gravitational radiation by the Doppler tracking of spacecraft  

International Nuclear Information System (INIS)

It has been suggested that the residual Doppler shift in the precision electromagnetic tracking of spacecraft be used to search for gravitational radiation that may be incident on the Earth-spacecraft system. The influence of a gravitational wave on the Doppler shift is calculated, and it is found that the residual shift is dominated by two terms: one is due to the passage of electromagnetic waves through the gravitational radiation field, and the other depends on the change in the relative velocity of the Earth and the spacecraft caused by the external wave. A detailed analysis is given of the influence of gravitational radiation on a binary system with an orbital size small compared to the wavelength of the incident radiation. It is shown that, as a consequence of the interaction with the external wave, the system makes a transition from one Keplerian orbit into another which, in general, has a different energy and angular momentum. It is therefore proposed to search for such effects in the solar system. Observations of the orbit of an artificial Earth satellite, the lunar orbit, and especially the planetary orbits offer exciting possibilities for the detection of gravitational waves of various wavelengths. From the results of the lunar laser ranging experiment and the range measurement to Mars, certain interesting limits may be established on the frequency of incidence of gravitational waves of a given flux on the Earth-Moon and the Earth-Mars systems. This is folln and the Earth-Mars systems. This is followed by a brief and preliminary analysis of the possibility of detecting gravitational radiation by measuring a residual secular Doppler shift in the satellite-to-satellite Doppler tracking of two counterorbiting drag-free spacecraft around the Earth as in the Van Patten-Everitt experiment

285

Spectral Analysis Method of Plastic Scintillator-based Radiation Detector against Nuclear/Radiological Terrorism  

International Nuclear Information System (INIS)

In these days, the threats relating to nuclear or radioactive materials have become a matter of internationally increased grave concern. A plastic scintillation detector in radiation portal monitoring (RPM) application has been used to detect radioactive sources in steel scrap entering reprocessing facilities, and to detect illicit transport of radioactive material across border ports-of-entry. The detection systems for RPM application usually are large and can not easily be moved to a different location. For some situations, an inconspicuous and mobile system for the radioactive or nuclear material during road transport is needed. The mobile radiation detection system has employed a NaI- based radiation detector to detect and identify the material hidden in vehicle. There are some operational constraints - short measuring time, weak activity due to heavy shield of illegal source, long distance - of inspection system in such nuclear security applications. Due to these constraints, large area sensor is required to maximize its sensitivity. Large NaI material, however, is extremely expensive. In designing a radiation detector for prevention of illicit trafficking of nuclear or radioactive materials, the trade-off should be carefully optimized between performance and cost in order to achieve cost-effective inspection system. For the cost-effective mobile radiation detection system, this paper describes new spectral analysis method to use the crude spectroscopic informatid to use the crude spectroscopic information available from a plastic detector to discriminate other man-made radiation source from NORM

286

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)

287

Sensing Methods for Detecting Analog Television Signals  

Science.gov (United States)

This paper introduces a unified method of spectrum sensing for all existing analog television (TV) signals including NTSC, PAL and SECAM. We propose a correlation based method (CBM) with a single reference signal for sensing any analog TV signals. In addition we also propose an improved energy detection method. The CBM approach has been implemented in a hardware prototype specially designed for participating in Singapore TV white space (WS) test trial conducted by Infocomm Development Authority (IDA) of the Singapore government. Analytical and simulation results of the CBM method will be presented in the paper, as well as hardware testing results for sensing various analog TV signals. Both AWGN and fading channels will be considered. It is shown that the theoretical results closely match with those from simulations. Sensing performance of the hardware prototype will also be presented in fading environment by using a fading simulator. We present performance of the proposed techniques in terms of probability of false alarm, probability of detection, sensing time etc. We also present a comparative study of the various techniques.

Rahman, Mohammad Azizur; Song, Chunyi; Harada, Hiroshi

288

Detection of graphite radiation damage in HTR based on wavelet transform  

International Nuclear Information System (INIS)

According to wavelet singularity detection principle and using its multi-scale analysis function that can manifest the local characteristics of signals, the change of graphite X ray diffraction graph in HTR is analyzed and the correspondence between wavelet transform model maximum and original signals singularity is to find out. Then the macroscopic damage location of the irradiated graphite can be accurately detected, which is caused by the micro-scale crystal lattice damage of the irradiated graphite. And it can improve the accuracy of graphite radiation damage detection. This study demonstrated that wavelet transform shows outstanding advantages on diagnostic performance of graphite radiation damage. Wavelet transform as a tool provides a new way for the analysis of the signal with a local singularity, and further provides a viable security method for the safety of HTR reactor. (author)

289

Detection of radiation-induced hydrocarbons and 2-alkylcyclobutanones in irradiated perilla seeds.  

Science.gov (United States)

The method consists of the extraction of fat from perilla seeds, separation of hydrocarbons and 2-alkylcyclobutanones with florisil column chromatography, and identification of hydrocarbons and 2-alkylcyclobutanones by gas chromatography-mass spectroscopy (GC-MS). Concentrations of hydrocarbons and 2-alkylcyclobutanones increased with the irradiation dose. The major hydrocarbons in the irradiated perilla seeds were 8-heptadecene and 1,7-hexadecadiene from oleic acid and 6,9-heptadecadiene and 1,7,10-hexadecatriene from linoleic acid. One of the 2-alkylcyclobutanones, 2-(5'-tetradecenyl)cyclobutanone, was found in the highest concentration in the irradiated perilla seeds. Radiation-induced hydrocarbons in the perilla seeds were detected at doses of 0.5 kGy and higher, and radiation-induced 2-alkylcyclobutanones were detected at doses of 1 kGy and higher. These compounds were not detected in nonirradiated perilla seeds. PMID:11079701

Lee, H J; Byun, M W; Kim, K S

2000-11-01

290

Novelty detection using level set methods.  

Science.gov (United States)

This paper presents a level set boundary description (LSBD) approach for novelty detection that treats the nonlinear boundary directly in the input space. The proposed approach consists of level set function (LSF) construction, boundary evolution, and termination of the training process. It employs kernel density estimation to construct the LSF of the initial boundary for the training data set. Then, a sign of the LSF-based algorithm is proposed to evolve the boundary and make it fit more tightly in the data distribution. The training process terminates when an expected fraction of rejected normal data is reached. The evolution process utilizes the signs of the LSF values at all training data points to decide whether to expand or shrink the boundary. Extensive experiments are conducted on benchmark data sets to evaluate the proposed LSBD method and compare it against four representative novelty detection methods. The experimental results demonstrate that the novelty detector modeled with the proposed LSBD can effectively detect anomalies. PMID:25720011

Ding, Xuemei; Li, Yuhua; Belatreche, Ammar; Maguire, Liam P

2015-03-01

291

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

292

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

Energy Technology Data Exchange (ETDEWEB)

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.

Kortmann, Onno; Martin, Cesar; Boehm, Eckart; Boettcher, Stephan; Wimmer-Schweingruber, Robert F.; Burmeister, Soenke; Ehresmann, Bent [Institut fuer Experimentelle und Angewandte Physik, Christian-Albrechts-Universitaet, Leibnizstrasse 11, Kiel, 24118 (Germany); Hassler, Donald M.; Zeitlin, Cary; Rafkin, Scott [Southwest Research Institute, 1050 Walnut St., Boulder, CO 80302 (United States); Posner, Arik; Weigle, Eddie; Neal, Kerry [Southwest Research Institute, 9503 W Commerce St., San Antonio, TX 78227 (United States); Posner, Arik [NASA-HQ, Heliophysics Division 300 E St. SW, Washington, DC 20546 (United States); Reitz, Guenther [Deutsches Zentrum fuer Luft- und Raumfahrt, Aerospace Medicine, Radiation Biology, Linder Hoehe, Koeln, 51147 (Germany)

2009-07-01

293

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.

294

Method of detecting failed fuel elements  

International Nuclear Information System (INIS)

Purpose: To detect failures in nuclear fuels at high accuracy. Method: Output from a delayed neutron detector comprising a background counting value and a nuclear fission product counting value superimposed to each other is applied to a deviation calculation circuit. While on the other hand, output from a reactor power measuring system is applied to a counting model and the counting rate for the background depending on the reactor power is applied from the counting model to the deviation calculation circuit. Then, the deviation is calculated and the calculation output is compared with a predetermined threshold value. If the output is greater than the threshold value, an alarm or safety protection system is actuated to detect the failures in fuel elements. (Moriyama, K.)

295

Nick translation detection in situ of cellular DNA strand break induced by radiation.  

OpenAIRE

DNA strand break in HeLa cells induced by radiation was detected using the in situ nick translation method. The cells were exposed to radiation of 3, 6, 12, 18, and 24 Gy in Lab-Tek tissue culture chamber/slides and were fixed with ethanol/acetic acid on the slide glass. The break sites in DNA were translated artificially in the presence of Escherichia coli DNA polymerase I and [3H]-labeled dTTP. Autoradiographic observation was made of the level of break sites in the DNA. The DNA strand brea...

Maehara, Y.; Anai, H.; Kusumoto, T.; Sakaguchi, Y.; Sugimachi, K.

1989-01-01

296

Radiative neutron capture cross section measurements using the spectrum method  

International Nuclear Information System (INIS)

The capture cross section is determined through the ? ray spectrum emitted by the sample. The ? rays are detected with a central NaI scintillator surrounded by a NaI annulus. The spectrometer is used both in the anti-Compton and first escape modes at the same time. The time-of-flight technique is used to reduce the background. The pulse-height spectrum is unfolded and corrected for the spectrometer efficiency. A theoretical calculation is used to extrapolate the capture ?-ray spectrum below the experimental threshold or in the region containing ?-rays from the (n,n'?) reaction. The radiative capture cross section is then deduced from the capture spectrum. The method is applied to the capture cross section measurements of gold for 0.5 to 3.0 MeV neutrons

297

Detection of irradiated powdered foods using photostimulated luminescence method  

International Nuclear Information System (INIS)

Photostimulated luminescence (PSL) method provides a rapid and markedly sensitive technique to detect of any irradiated food that contain minerals. This method is also convenient as a first screening means in comparison with thermoluminescence (TL) method which requires separating minerals from the food materials. The present study reports the results of PSL measurements for both irradiated and non-irradiated powdered dry leaf vegetable obtained with the prototype of PSL system developed by our groups. This PSL system consists of pulsed Infra-Red (IR) source for photostimulation, single photon counting system for high sensitive detection of luminescence, and computer for data treatments. The PSL intensity of the leaf vegetable increased with increase of gamma radiation dose and show a linear relationship up to a dose of 1kGy. The PSL intensities after four months of storage under light shielding following gamma irradiation (0.49?3.1kGy) decreased to less than half of initial intensities. The PSL intensities of those decreased rapidly for 60 seconds and reached a steady level close to intensity of non-irradiated sample after 300 seconds following photostimulation. We used the information on the shape and slope of PSL intensity curve as a criteria to discriminate whether irradiated foods or not, and possible to detect the irradiation history of food irradiated with a 0.49kGy dose after four months of storage. (author)

298

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.)

299

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

300

Nick translation detection in situ of cellular DNA strand break induced by radiation  

International Nuclear Information System (INIS)

DNA strand break in HeLa cells induced by radiation was detected using the in situ nick translation method. The cells were exposed to radiation of 3, 6, 12, 18, and 24 Gy in Lab-Tek tissue culture chamber/slides and were fixed with ethanol/acetic acid on the slide glass. The break sites in DNA were translated artificially in the presence of Escherichia coli DNA polymerase I and [3H]-labeled dTTP. Autoradiographic observation was made of the level of break sites in the DNA. The DNA strand break appeared even with a 3 Gy exposure, increased 8.6 times at 24 Gy compared with the control cells, and this level correlated reciprocally to change in cell viability. This nick translation method provides a rapid in situ assay for determining radiation-induced DNA damage of cultured cells, in a semi-quantitative manner

301

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.)

302

Method prevents secondary radiation in radiographic inspection  

Science.gov (United States)

Thin-walled neoprene containers prevent secondary radiation, scatter, and undercut during radiographic inspection. The containers are filled with a mixture of barium sulfate, red lead, and petroleum jelly that achieves the required absorption rate.

Struckus, A. A.

1967-01-01

303

Generation and detection of Terahertz radiation by Field Effect Transistors  

CERN Document Server

This is a brief overview of the main physical ideas for application of field effect transistors for generation and detection of TeraHertz radiation. Resonant frequencies of the two-dimensional plasma oscillations in FETs increase with the reduction of the channel dimensions and reach the THz range for sub-micron gate lengths. When the mobility is high enough, the dynamics of a short channel FET at THz frequencies is dominated by plasma waves. This may result, on the one hand, in a spontaneous generation of plasma waves by a dc current and on the other hand, in a resonant response to the incoming radiation. In the opposite case, when plasma oscillations are overdamped, the FET can operate as an efficient broadband THz detector.

Dyakonov, M I

2011-01-01

304

Improvements in or relating to the detection of radiation  

International Nuclear Information System (INIS)

A novel detector is described for use with a rotation only scanner in computerised axial tomography; the form of the detector overcomes the drift problems associated with the use of photomultipliers in conventional X-ray detection. The detector consists of a scintillator crystal such as caesium iodide whose resulting visible radiation is indicative of the amount of ionising radiation incident upon the crystal and which is viewed by a photo-diode. The photo-diode is operated in the photovoltaic current mode and the p-n junction is arranged to be close to the illuminated surface (typically up to 1.0 ?m depth). A possible circuit for integrating the induced electron current is also described. (U.K.)

305

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

306

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

307

Detection of anisotropy in the cosmic blackbody radiation  

International Nuclear Information System (INIS)

We have detected anisotropy in the cosmic blackbody radiation with a 33-GHz (0.9 cm) twin-antenna Dicke radiometer flown to an altitude of 20 km aborad a U-2 aircraft. In data distributed over two-thirds of the northern hemisphere, we observed an anisotropy which is well fitted by a first-order spherical harmonic with an amplitude of (3.5 +- 0.6) x 10-3 0K, and direction [11.0 +- 0.6 h right ascension (R.A.) and 60 +- 100 declination (dec)]. This observation is readily interpreted as due to motion of the earth relative to the radiation with a veliocity of 390 +- 60 km/sec

308

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

309

Some methods for the detection of fissionable matter; Quelques methodes de detection des corps fissiles  

Energy Technology Data Exchange (ETDEWEB)

A number of equipments or processes allowing to detect uranium or plutonium in industrial plants, and in particular to measure solution concentrations, are studied here. Each method has its own field of applications and has its own performances, which we have tried to define by calculations and by experiments. The following topics have been treated: {gamma} absorptiometer with an Am source, detection test by neutron multiplication, apparatus for the measurement of the {alpha} activity of a solution, fissionable matter detection by {gamma} emission, fissionable matter detection by neutron emission. (author) [French] On examine ici plusieurs appareils ou procedes qui permettent de detecter l'uranium ou le plutonium dans les installations industrielles, et en particulier de mesurer les concentrations de solutions. Chacune des methodes a son domaine d'application et ses performances, qu'on a tente de definir par le calcul et par des experiences. Les sujets traites sont les suivants: absorptiometre {gamma} a source d'americium, essais de detection par multiplication neutronique, appareil de mesure de l'activite {alpha} d'une solution, detection des matieres fissiles par leur emission {gamma}, detection des matieres fissiles par leur emission neutronique. (auteur)

Guery, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1967-03-01

310

Novel Methods of Hydrogen Leak Detection  

International Nuclear Information System (INIS)

For hydrogen to become a consumer fuel for automotive and domestic power generation, safety is paramount. Today's hydrogen systems are built with inherent safety measures and multiple levels of protection. However, human senses, in particular, the sense of smell, is considered the ultimate safeguards against leaks. Since hydrogen is an odorless gas, use of odorants to detect leaks, as is done in case of natural gas, is obvious solution. The odorants required for hydrogen used in fuel cells have a unique requirement which must be met. This is because almost all of the commercial odorants used in gas leak detection contain sulfur which acts as poison for the catalysts used in hydrogen based fuel cells, most specifically for the PEM (polymer electrolyte membrane or proton exchange membrane) fuel cells. A possible solution to this problem is to use non-sulfur containing odorants. Chemical compounds based on mixtures of acrylic acid and nitrogen compounds have been adopted to achieve a sulfur-free odorization of a gas. 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. A series of novel solutions are proposed which address the issues raised above. Theshich 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 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. (O.M.)

311

Novel Methods of Hydrogen Leak Detection  

Energy Technology Data Exchange (ETDEWEB)

For hydrogen to become a consumer fuel for automotive and domestic power generation, safety is paramount. Today's hydrogen systems are built with inherent safety measures and multiple levels of protection. However, human senses, in particular, the sense of smell, is considered the ultimate safeguards against leaks. Since hydrogen is an odorless gas, use of odorants to detect leaks, as is done in case of natural gas, is obvious solution. The odorants required for hydrogen used in fuel cells have a unique requirement which must be met. This is because almost all of the commercial odorants used in gas leak detection contain sulfur which acts as poison for the catalysts used in hydrogen based fuel cells, most specifically for the PEM (polymer electrolyte membrane or proton exchange membrane) fuel cells. A possible solution to this problem is to use non-sulfur containing odorants. Chemical compounds based on mixtures of acrylic acid and nitrogen compounds have been adopted to achieve a sulfur-free odorization of a gas. 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. 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 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. (O.M.)

Pushpinder S Puri [Air Products and Chemicals, Inc. Allentown, Pennsylvania (United States)

2006-07-01

312

Poly (ether sulfone) as a scintillation material for radiation detection  

International Nuclear Information System (INIS)

Considerable attention has been drawn to the advantages of using aromatic ring polymers for scintillation materials in radiation detection. Thus, it is important to identify and characterise those with the best potential. Here, we characterise poly (ether sulfone) (PES), which is an amber-coloured transparent resin that possesses sulfur as a main component and has a density of 1.37 g/cm3. PES emits short-wavelength light with a 350-nm maximum. By taking into account its emission spectrum, we demonstrate that its effective refractive index is 1.74. Light yield distributions generated by 137Cs and 207Bi radioactive sources were obtained. PES has a light yield that is 2.21 times that of poly (ethylene terephthalate), and 0.31 times that of poly (ethylene naphthalate). The energy response to 5486 keV alpha particles emitted from 241Am was 546±81 keV electron equivalents (keVee), while the energy resolution was 17.0±0.1%. The energy response to 6118 keV alpha particles emitted from 252Cf was 598±83 keVee, while the energy resolution was 16.0±0.1%. Overall, PES has potential for use as a scintillation material in radiation detection. - Highlights: • PES is characterised as a scintillation material for radiation detection. • PES has an emission maximum at 350 nm. • The effective refractive index for PES is 1.74 based on its emission spectrum. • The light yield of PES is 2.21 that of PET and 0.31 times that of PEN. • The PES response to 5486 (6118) keV alpha particles is 546±81 (598±83) keV electron equivalents

313

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

314

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. PMID:25698950

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

315

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. PMID:25698950

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

316

Method and apparatus for determining the accuracy of radiation measurements  

International Nuclear Information System (INIS)

A radioactivity measuring instrument, and a method related to its use for determining the radioactivity of a sample measured in the presence of significant background radiation, and for determining an error value relating to a specific probability of accuracy of the result are described. Error values relating to the measurement of background radiation alone, and to the measurement of sample radiation and background radiation together, are combined to produce a true error value relating to the sample radiation alone. A data processor displaying the error values is attached

317

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

318

Platelet antibody: review of detection methods  

International Nuclear Information System (INIS)

The driving force behind development of in vitro methods for platelet antibodies is identification of plasma factors causing platelet destruction. Early methods relied on measurement of platelet activation. Current methods are more specific and use a purified antibody against immunoglobulin or complement, which is usually labeled with 125I or tagged with an enzyme or fluorescein. Comparisons of quantitation of platelet-associated IgG show wide variability between different methods. The disparate results can be related both to differences in binding of secondary antibodies to immunoglobulin in solution compared to immunoglobulins attached to platelets and to the improper assumption that the binding ratio between the secondary detecting and primary antiplatelet antibody is one. Most assays can 1) identify neonatal isoimmune thrombocytopenia and posttransfusion purpura, 2) help to differentiate between immune and nonimmune thrombocytopenias, 3) help to sort out the offending drug when drug-induced thrombocytopenia is suspected, and 4) identify platelet alloantibodies and potential platelet donors via a cross match assay for refractory patients. However, the advantages of quantitative assays over qualitative methods with respect to predictions of patients clinical course and response to different treatments remain to be investigated. 61 references

319

Platelet antibody: review of detection methods  

Energy Technology Data Exchange (ETDEWEB)

The driving force behind development of in vitro methods for platelet antibodies is identification of plasma factors causing platelet destruction. Early methods relied on measurement of platelet activation. Current methods are more specific and use a purified antibody against immunoglobulin or complement, which is usually labeled with /sup 125/I or tagged with an enzyme or fluorescein. Comparisons of quantitation of platelet-associated IgG show wide variability between different methods. The disparate results can be related both to differences in binding of secondary antibodies to immunoglobulin in solution compared to immunoglobulins attached to platelets and to the improper assumption that the binding ratio between the secondary detecting and primary antiplatelet antibody is one. Most assays can 1) identify neonatal isoimmune thrombocytopenia and posttransfusion purpura, 2) help to differentiate between immune and nonimmune thrombocytopenias, 3) help to sort out the offending drug when drug-induced thrombocytopenia is suspected, and 4) identify platelet alloantibodies and potential platelet donors via a cross match assay for refractory patients. However, the advantages of quantitative assays over qualitative methods with respect to predictions of patients clinical course and response to different treatments remain to be investigated. 61 references.

Schwartz, K.A.

1988-10-01

320

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

321

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.))

322

 Methods of detection of selected respiratory viruses  

Directory of Open Access Journals (Sweden)

Full Text Available  Respiratory viruses contribute to significant morbidity and mortality in healthy and immunocompromised individuals and are considered as a significant economic burden in the healthcare system. The similar clinical symptoms in the course of different viral and bacterial respiratory infections make the proper diagnosis difficult. An accurate and prompt diagnostics is crucial for infection control and patient management decisions, especially regarding the use of antibacterial or antiviral therapy and hospitalization. Moreover, the identification of the causative agent eliminates inappropriate use of antibiotics and may reduce the cost of healthcare.A wide variety of diagnostic procedures is applied for the detection of viral agents responsible for respiratory tract infections. For many years, the viral antigen detection and standard isolation technique in cell culture was the main method used in routine diagnostics. However, in recent years the nucleic acid amplification techniques have become widely used and have significantly improved the sensitivity of viral detection in clinical specimens. Molecular diagnostic assays have contributed to revealing high rates of co-infection (multiplex reactions and allow identification of agents that are difficult to culture.This paper discusses a number of technical aspects of the current most commonly used techniques, their general principles, main benefits and diagnostic value, but also some of their limitations.

Ilona Stefa?ska

2012-06-01

323

Tank leak detection using electrical resistance methods  

International Nuclear Information System (INIS)

Two field experiments were performed to evaluate the performance of electrical resistance tomography (ERT) as a leak detection method under metal underground storage tanks (UST). This paper provides a summary of the field experiments performed under a 15 m diameter steel tank mockup located at the Hanford Reservation, Washington. Two different leak events were created. About 3800 liters of saline solution were first released along a portion of the tank's edge and another 1900 liters were later released near the tank's center. The release rate averaged about 26 liters/hour for the leak on the tank's side and about 3.0 liters/hour for the center leak. Two and three dimensional tomographs were calculated using data collected before, during and after each spill. The tomographs show that, as the solution penetrated the soil, readily detectable resistivity decreases appeared where the associated plume was expected. The results indicate that the plume associated with these releases could be reliably detected after approximately 190 liters were released. Results are also shown where the metal tank is used as a large electrode

324

Non-contact acoustic radiation force impulse microscopy via photoacoustic detection for probing breast cancer cell mechanics.  

Science.gov (United States)

We demonstrate a novel non-contact method: acoustic radiation force impulse microscopy via photoacoustic detection (PA-ARFI), capable of probing cell mechanics. A 30 MHz lithium niobate ultrasound transducer is utilized for both detection of phatoacoustic signals and generation of acoustic radiation force. To track cell membrane displacements by acoustic radiation force, functionalized single-walled carbon nanotubes are attached to cell membrane. Using the developed microscopy evaluated with agar phantoms, the mechanics of highly- and weakly-metastatic breast cancer cells are quantified. These results clearly show that the PA-ARFI microscopy may serve as a novel tool to probe mechanics of single breast cancer cells. PMID:25657870

Hwang, Jae Youn; Kang, Bong Jin; Lee, Changyang; Kim, Hyung Ham; Park, Jinhyoung; Zhou, Qifa; Shung, K Kirk

2015-01-01

325

Radiation Pressure Detection and Density Estimate for 2011 MD  

Science.gov (United States)

We present our astrometric observations of the small near-Earth object 2011 MD (H ~ 28.0), obtained after its very close fly-by to Earth in 2011 June. Our set of observations extends the observational arc to 73 days, and, together with the published astrometry obtained around the Earth fly-by, allows a direct detection of the effect of radiation pressure on the object, with a confidence of 5?. The detection can be used to put constraints on the density of the object, pointing to either an unexpectedly low value of \\rho = (640+/- 330) kg \\, m ^{-3} (68% confidence interval) if we assume a typical probability distribution for the unknown albedo, or to an unusually high reflectivity of its surface. This result may have important implications both in terms of impact hazard from small objects and in light of a possible retrieval of this target.

Micheli, Marco; Tholen, David J.; Elliott, Garrett T.

2014-06-01

326

Heat Induced Damage Detection by Terahertz (THz) Radiation  

Science.gov (United States)

Terahertz (THz) and sub-terahertz imaging and spectroscopy are becoming increasingly popular nondestructive evaluation techniques for damage detection and characterization of materials. THz radiation is being used for inspecting ceramic foam tiles used in TPS (Thermal Protection System), thick polymer composites and polymer tiles that are not good conductors of ultrasonic waves. Capability of THz electromagnetic waves in detecting heat induced damage in porous materials is investigated in this paper. Porous pumice stone blocks are subjected to long time heat exposures to produce heat induced damage in the block. The dielectric properties extracted from THz TDS (Time Domain Spectroscopy) measurements are compared for different levels of heat exposure. Experimental results show noticeable and consistent change in dielectric properties with increasing levels of heat exposure, well before its melting point.

Rahani, Ehsan Kabiri; Kundu, Tribikram; Wu, Ziran; Xin, Hao

2011-06-01

327

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

328

Damage Detection Based on Model Updating Methods  

Science.gov (United States)

The paper examines the problem of detecting the location and extent of structural damage from measured vibration test data. The method is based upon a mathematical model representing the undamaged vibrating structure and a local description of the damage, e.g. a finite element for a cracked beam. The problem of modeling errors and their influence to damage localisation accuracy is discussed and an approach to obtain reliable results in this case is presented. The concept of inverse sensitivity equations is used which can be based on any type of data, e.g. modal data, FRFs, time series, or a combination of these. The resulting inverse problem usually is ill-posed, and therefore special attention is required for an accurate solution. The application to damage detection problems requires the reduction of a large set of damage parameter candidates to a small subset of one or two parameters that actually describes the local change of the system. An orthogonalisation strategy is given to reduce the parameter set. The method is demonstrated through application to laboratory structures in the frequency domain using frequency response functions and in the time domain.

Fritzen, C.-P.; Jennewein, D.; Kiefer, T.

1998-01-01

329

Rogowski coil of detecting compton electron beam in radiation environment  

International Nuclear Information System (INIS)

Operating principle of detecting Compton electron beam was presented using Rogowski coil. The response of Rogowski coil to rectangle pulse was analysed in self-integration condition. The designing thought of symmetrical differential resist-interfere was raised. A winding method of coil, coil shelf, resistance of resist-vibration selected and calibrating method was introduced. The Rogowski coil with resist-interfere design successfully detected Compton current. There is well a consistency of measuring results by Rogowski coil with measuring results of IEMP magnetic-field and ? dose rate. (author)

330

Comparison of three methods of microsatellite detection  

DEFF Research Database (Denmark)

Examination of microsatellites is frequent in the diagnosis of cancer. Microsatellites are repeat DNA sequences scattered throughout the human genome. These repeat regions are very frequent and highly polymorphic elements. In this study we focus on dinucleotide repeats. We compared three different methods for the detection of microsatellites: use of the ABI Prism 377 fluorescence sequencer, autoradiography and silver-stained gels. DNA was extracted from various clinical samples and amplified by different polymerase chain reaction (PCR) protocols. DNA from normal and tumor tissues was analysed using each method. The fluorescence method was more sensitive than the two other methods; however, this technology is very expensive. It seems possible, when examining microsatellites on a low budget, to avoid radioactivity by using silver-stained gels as an alternative. In conclusion, we observed identical results when comparing autoradiography with the fluorescence technique. However, we observed variability in the results when interpreting a single locus comparing silver staining with autoradiography and the fluorescence technique. Classification of the tumors based on several microsatellite loci was always identical.

Christensen, Mariann; Sunde, Lone

1999-01-01

331

Nucleic acid detection system and method for detecting influenza  

Energy Technology Data Exchange (ETDEWEB)

The invention provides a rapid, sensitive and specific nucleic acid detection system which utilizes isothermal nucleic acid amplification in combination with a lateral flow chromatographic device, or DNA dipstick, for DNA-hybridization detection. The system of the invention requires no complex instrumentation or electronic hardware, and provides a low cost nucleic acid detection system suitable for highly sensitive pathogen detection. Hybridization to single-stranded DNA amplification products using the system of the invention provides a sensitive and specific means by which assays can be multiplexed for the detection of multiple target sequences.

Cai, Hong; Song, Jian

2015-03-17

332

Radiation detection using long lasting phosphor (luminous paint)  

International Nuclear Information System (INIS)

The detection characteristic of long lasting phosphor (LLP, SrAl2O4; Eu2+, Dy3+) has been studied in ?, ?, and ? radiation field. It was found that the total luminous intensity of LLP had linear response over a wide range of absorbed energy for all radiations. The luminous intensity showed significant temperature dependence and the peak intensity was observed near room temperature. The thermoluminescence glow curve suggested that the luminosity of LLP consisted of 4-components and the time profile of LLP luminescence was found to be described by a simple sum of these components. The Arrhenius plot of escape rates calculated from the afterglow region provided the activation energies of escape process form trap levels and these values were ranged from 24 meV to 0.34 eV, which corresponded to the escape rates of 0.8-8.3x103 s-1 at room temperature. The trapping ratios to the 4 traps were also determined from afterglow ratio curves and had no temperature dependence. These trapping ratios were ranging from 0.16 to 0.35 for ? and ? irradiation and slightly different values were obtained for ? rays. The experimental time profile can be fitted within experimental error using the trapping ratios and escape rates. Various applications of LLP will be expected as radiation detectors, especially as 2-dimensional imaging devices. (author)

333

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

334

Thermoluminescence method for detection of irradiated food  

International Nuclear Information System (INIS)

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.)

335

Materials Discovery: Informatic Strategies for Semiconducting Radiation Detection Materials  

Science.gov (United States)

Inorganic semiconducting materials used in gamma radiation detection applications are typically binary and ternary inorganic crystals. Performance metrics for these materials include band gap, relating to carrier concentration and thermal background current; density, relating to stopping power; and electron mobility, which limits electron transport and is typically the dominant information carrier. In this paper, we describe an information-based approach to the identification of new radiation detection materials, using the specific case of the II-VI semiconductors. Even for simple binary systems, the sheer number of potential materials considering the presence of crystal system polymorphs and higher order compositions is daunting. The key to a successful materials search is the ability to suggest promising materials and a priori eliminate unfruitful inquiry. The success of an informatics-based design program depends on the relation of materials-level properties to atomic-scale properties that change rationally with structure, and the ability to extract rules which define these mappings. A brief example of a property-level screen will be given to illustrate the materials development process. The authors gratefully acknowledge financial support from U.S. Department of Homeland Security under Contract No. HSHQDC-08-X-00872.

Ferris, Kim; Jones, Dumont; Schultz, Brian

2010-03-01

336

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.

337

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

338

DETECCIÓN DE RADIACIÓN NO IONIZANTE / NON-IONIZING RADIATION DETECTION  

Scientific Electronic Library Online (English)

Full Text Available Se diseñó y construyó una red de sensores para detección de radiación no ionizante en la banda comprendida entre 800MHz y 2.5GHz. El sistema se basa en el sensor que muestra a la salida una tensión DC proporcional a la potencia de la señal RF a su entrada, sin importar el tipo de modulación. Esta re [...] d comprende cuatro antenas banda ancha, cuatro tarjetas sensoras, una tarjeta central y un software de visualización de datos. El comportamiento del sistema se analizó con diferentes configuraciones y con múltiples fuentes de radiación. Igualmente, se muestran los resultados de la simulación de una antena espiral de Arquímedes utilizando CST STUDIO TM y los experimentos realizados para caracterizar la antena banda ancha HG2404CU. Los resultados mostraron un eficiente sistema de detección de radiación electromagnética en la banda estudiada. Una aplicación inmediata de este trabajo, para la cual se están haciendo pruebas de campo, es la detección de llamadas de celulares en lugares no permitidos como centros carcelarios, bancos, entre otros. Abstract in english A sensors network for non-ionizing radiation detection in the band of 800 MHz to 2.5 GHz was designed and constructed. The system is based on a sensor which shows an output DC voltage proportional to the input RF signal. This network is made of four broad band antennas, four circuit board sensors, a [...] main board and data visualization software. The performance system was analyzed changing its configuration and using several radiation sources. The results presented include the simulation of an Archimedes antenna using CST STUDIO TM and the experimental results of a broad band HG2404CU antenna. The results have shown an efficient system for the electromagnetic radiation detection. As a second part of this work, this prototype will be used as a detector of cellular phone calls in places where they are not allowed such as prisons, banks and so on.

GUSTAVO, NAVAS; JAIRO, TARAZONA; RODRIGO, CORREA.

2009-12-01

339

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

340

Molecular methods of virus detection in lymphoma.  

Science.gov (United States)

The herpesviruses Epstein-Barr virus (EBV) and human herpesvirus 8 and the retrovirus human T-cell leukemia virus type 1 are directly implicated in the pathogenesis of lymphoma and leukemia in man. EBV is associated with an expanding spectrum of lymphomas and it would appear likely that additional, possibly novel, viruses will be implicated in lymphoma pathogenesis in the future. This chapter describes techniques that may be useful in the analysis of viruses and lymphoma including a standard EBV EBER in situ hybridization assay and a degenerate PCR assay for detection of novel herpesviruses. Lastly, a method for analysis of next-generation sequences in the quest for novel viruses is described. PMID:23296970

Jarrett, Ruth F; Gallagher, Alice; Gatherer, Derek

2013-01-01

341

Method of detecting a fuel element failure  

International Nuclear Information System (INIS)

A method is described for detecting a fuel element failure in a liquid-sodium-cooled fast breeder reactor consisting of equilibrating a sample of the coolant with a molten salt consisting of a mixture of barium iodide and strontium iodide (or other iodides) whereby a large fraction of any radioactive iodine present in the liquid sodium coolant exchanges with the iodine present in the salt; separating the molten salt and sodium; if necessary, equilibrating the molten salt with nonradioactive sodium and separating the molten salt and sodium; and monitoring the molten salt for the presence of iodine, the presence of iodine indicating that the cladding of a fuel element has failed. (U.S.)

342

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

343

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

344

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.

345

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

346

Investigation of radiation defects in solids using the EXAFS method  

International Nuclear Information System (INIS)

The exafs method is proposed as a more informative, universal one to investigate the radiation defects in solids. The successful results as obtained by the author using the synchrotron radiation source are reported for the first time. The measurements were carried out in GaAsP crystals irradiated with 50 MeV electrons

347

Revealing Method for the Intrusion Detection System  

OpenAIRE

The goal of an Intrusion Detection is inadequate to detect errors and unusual activity on a network or on the hosts belonging to a local network by monitoring network activity. Algorithms for building detection models are broadly classified into two categories, Misuse Detection and Anomaly Detection. The proposed approach should be taken into account, as the security system violations caused by both incompliance with the security policy and attacks on the system resulting in...

Khan, M. Sadiq Ali

2010-01-01

348

Detection of radiation cardiomyopathy by gated radionuclide angiography  

International Nuclear Information System (INIS)

Twenty-one asymptomatic adults underwent rest and exercise gated radionuclide angiography seven to 20 years after having received mediastinal radiation (2,000 to 7,600 rads) for Hodgkin's disease. None of these patients received cytotoxic chemotherapy. Twelve patients (57 percent) had abnormal left (less than 53 percent at rest and/or greater than 5 percent decrease at peak exercise) and/or right (less than 27 percent at rest and/or greater than 5 percent decrease at peak exercise) ventricular ejection fractions. Previous reports have described myocardial fibrosis occurring late after therapeutic mediastinal radiation; however, the incidence of this occurrence based on clinical follow-up has been low. Rest and exercise radionuclide angiography is a sensitive method for assessing systolic ventricular function and reveals a high prevalence of cardiomyopathy that can be linked to previous radiotherapy

349

Detection methods for irradiated foods developed in the INCT  

International Nuclear Information System (INIS)

The task of the Laboratory for Detection of Irradiated food is to develop and implement analytical methods which allow to confirm whether food was or was not irradiated. Owing to the fact that not all the methods are enough reliable when adapted to a given kind of food the complementary methods are usually adapted. The following detection methods have been developed: - the method based on EPR spectrometry: (a) for detection of foods which contains bones, (b) for detection of food contains cellulose, (c) for detection of foods which contain sugars, (d) for detection mushrooms and partially processed food; - thermoluminescence method for detection of food from which silicate minerals are separated; - DNA comet assay for detection of food from which single cells can be isolated; - germination test for detection of irradiated seeds; - gas chromatography of hydrocarbon fraction separated from fats. (author)

350

Using Thermal Radiation in Detection of Negative Obstacles  

Science.gov (United States)

A method of automated detection of negative obstacles (potholes, ditches, and the like) ahead of ground vehicles at night involves processing of imagery from thermal-infrared cameras aimed at the terrain ahead of the vehicles. The method is being developed as part of an overall obstacle-avoidance scheme for autonomous and semi-autonomous offroad robotic vehicles. The method could also be applied to help human drivers of cars and trucks avoid negative obstacles -- a development that may entail only modest additional cost inasmuch as some commercially available passenger cars are already equipped with infrared cameras as aids for nighttime operation.

Rankin, Arturo L.; Matthies, Larry H.

2009-01-01

351

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

352

Ferromagnetic Antenna and its Application to Generation and Detection of Gravitational Radiation  

CERN Document Server

A new type of antenna, which we have called Ferromagnetic Antenna, has been considered for Generation and Detection of Gravitational Radiation. A simple experiment, in which gravitational radiation at 10 GHz can be emitted and received in laboratory, is presented.

De Aquino, F

2002-01-01

353

Radiation treatment method and apparatus for decontamination of polluted fluid  

International Nuclear Information System (INIS)

A radiation treatment method and apparatus for the safe disinfection and decontamination of liquid waste, such as sewage are described. Liquid waste is processed by removing some solids from the effluent, irradiating the effluent less some solids, with a gamma radiation field and percolating the disinfected effluent, or discharging the disinfected liquid into sewage conduits or into other bodies of water. The disinfecting chamber is a box constructed of concrete or other compatible material, having a radiation shielding cover, and having an inlet at one end and an exit at the other end. Baffles located in the box produce desired distribution and turbulence of flow. Sources of ionizing radiation, usually gamma radiation, are placed in the chamber in such a manner as to provide a relatively uniform radiation field in the effluent passing through the system. (auth)

354

Transport methods and interactions for space radiations  

Science.gov (United States)

A review of the program in space radiation protection at the Langley Research Center is given. The relevant Boltzmann equations are given with a discussion of approximation procedures for space applications. The interaction coefficients are related to solution of the many-body Schroedinger equation with nuclear and electromagnetic forces. Various solution techniques are discussed to obtain relevant interaction cross sections with extensive comparison with experiments. Solution techniques for the Boltzmann equations are discussed in detail. Transport computer code validation is discussed through analytical benchmarking, comparison with other codes, comparison with laboratory experiments and measurements in space. Applications to lunar and Mars missions are discussed.

Wilson, John W.; Townsend, Lawrence W.; Schimmerling, Walter S.; Khandelwal, Govind S.; Khan, Ferdous S.; Nealy, John E.; Cucinotta, Francis A.; Simonsen, Lisa C.; Shinn, Judy L.; Norbury, John W.

1991-01-01

355

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

356

Application of the microbiological method DEFT/APC and DNA comet assay to detect ionizing radiation processing of minimally processed vegetables; Aplicacao do metodo microbiologico DEFT/APC e do teste do cometa na deteccao do tratamento com radiacao ionizante de hortalicas minimamente processadas  

Energy Technology Data Exchange (ETDEWEB)

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 {sup 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)

Araujo, Michel Mozeika

2008-07-01

357

Present status of fuel motion detection by radiation  

International Nuclear Information System (INIS)

In reactor safety research, it is important to know transient fuel behavior under accidental conditions. Transient histories such as temperature and axial expansion of fuel and cladding and internal pressure of fuel rod are thus measured in experiments simulating accidents. If fuel motion could then be observed during and after fuel failure, this would greatly make for fuel behavior research. The present status is reviewed of fuel motion detections by radiations such as neutron, ?-ray and X-ray, including the principle and system. A neutron hodoscope among them is used already with practical results in in-reactor safety experiments of sodium-cooled fast breeder reactor. So, this is described in detail and its conceptual design as applied to the NSRR is presented. (auth.)

358

UTILIZATION OF PHOSWICH DETECTORS FOR SIMULTANEOUS, MULTIPLE RADIATION DETECTION  

Energy Technology Data Exchange (ETDEWEB)

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.

William H. Miller; Manuel Diaz de Leon

2003-04-15

359

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, and (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. (author)

360

Robust Eye and Pupil Detection Method for Gaze Tracking  

OpenAIRE

Robust and accurate pupil detection is a prerequisite for gaze detection. Hence, we propose a new eye/pupil detection method for gaze detection on a large display. The novelty of our research can be summarized by the following four points. First, in order to overcome the performance limitations of conventional methods of eye detection, such as adaptive boosting (Adaboost) and continuously adaptive mean shift (CAMShift) algorithms, we propose adaptive selection of the Adaboost and CAMShift met...

Su Yeong Gwon; Chul Woo Cho; Hyeon Chang Lee; Won Oh Lee; Kang Ryoung Park

2013-01-01

361

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.

362

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

363

Radiative Transfer in Star Formation: Testing FLD and Hybrid Methods  

CERN Document Server

We perform a comparison between two radiative transfer algorithms commonly employed in hydrodynamical calculations of star formation: grey flux limited diffusion and the hybrid scheme, in addition we compare these algorithms to results from the Monte-Carlo radiative transfer code MOCASSIN. In disc like density structures the hybrid scheme performs significantly better than the FLD method in the optically thin regions, with comparable results in optically thick regions. In the case of a forming high mass star we find the FLD method significantly underestimates the radiation pressure by a factor of ~100.

Owen, James E; Clarke, Cathie J

2012-01-01

364

Development of medical application methods using radiation. Radionuclide therapy  

International Nuclear Information System (INIS)

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

365

Improvement Methods in NPP's Radiation Emergency Plan: An Administrative Approach  

International Nuclear Information System (INIS)

The Radiation Emergency Plan (REP) can be divided into a technical and an administrative responses. The domestic NPP's REPs are reviewed from the viewpoint of the administrative response and improvement methods are also suggested in this treatise. The fields of the reviews are the composition of the emergency response organizations, the activation criteria of the organizations, the selection of the staffings and the reasonableness of the REP's volume. In addition, the limitations of the current radiation exercises are reviewed and the improvement method of the exercise is presented. It is expected that the suggested recommendations will be helpful in establishing useful REPs and making practical radiation exercises in Korea

366

An inverse method for radiation transport  

International Nuclear Information System (INIS)

Adjoint functions have been used with forward functions to compute gradients in implicit (iterative) solution methods for inverse problems in optical tomography, geoscience, thermal science and other fields, but only once has this approach been used for inverse solutions to the Boltzmann transport equation. In this paper, this approach is used to develop an inverse method that requires only angle-independent flux measurements, rather than angle-dependent measurements as was done previously. The method is applied to a simplified form of the transport equation that does not include scattering. The resulting procedure uses measured values of gamma-ray fluxes of discrete, characteristic energies to determine interface locations in a multilayer shield. The method was implemented with a Newton-Raphson optimisation algorithm and it worked very well in numerical 1-D spherical test cases. A more sophisticated optimisation method would better exploit the potential of the inverse method. (authors)

367

A new fault detection method for computer networks  

International Nuclear Information System (INIS)

Over the past few years, fault detection for computer networks has attracted extensive attentions for its importance in network management. Most existing fault detection methods are based on active probing techniques which can detect the occurrence of faults fast and precisely. But these methods suffer from the limitation of traffic overhead, especially in large scale networks. To relieve traffic overhead induced by active probing based methods, a new fault detection method, whose key is to divide the detection process into multiple stages, is proposed in this paper. During each stage, only a small region of the network is detected by using a small set of probes. Meanwhile, it also ensures that the entire network can be covered after multiple detection stages. This method can guarantee that the traffic used by probes during each detection stage is small sufficiently so that the network can operate without severe disturbance from probes. Several simulation results verify the effectiveness of the proposed method

368

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)

369

A Decision Theoretic Approach to Evaluate Radiation Detection Algorithms  

Energy Technology Data Exchange (ETDEWEB)

There are a variety of sensor systems deployed at U.S. border crossings and ports of entry that scan for illicit nuclear material. In this work, we develop a framework for comparing the performance of detection algorithms that interpret the output of these scans and determine when secondary screening is needed. We optimize each algorithm to minimize its risk, or expected loss. We measure an algorithm’s risk by considering its performance over a sample, the probability distribution of threat sources, and the consequence of detection errors. While it is common to optimize algorithms by fixing one error rate and minimizing another, our framework allows one to simultaneously consider multiple types of detection errors. Our framework is flexible and easily adapted to many different assumptions regarding the probability of a vehicle containing illicit material, and the relative consequences of a false positive and false negative errors. Our methods can therefore inform decision makers of the algorithm family and parameter values which best reduce the threat from illicit nuclear material, given their understanding of the environment at any point in time. To illustrate the applicability of our methods, in this paper, we compare the risk from two families of detection algorithms and discuss the policy implications of our results.

Nobles, Mallory A.; Sego, Landon H.; Cooley, Scott K.; Gosink, Luke J.; Anderson, Richard M.; Hays, Spencer E.; Tardiff, Mark F.

2013-07-01

370

Comparison of Methods for Oscillation Detection : case study  

DEFF Research Database (Denmark)

This paper compares a selection of methods for detecting oscillations in control loops. The methods are tested on measurement data from a coal-fired power plant, where some oscillations are occurring. Emphasis is put on being able to detect oscillations without having a system model and without using process knowledge. The tested methods show potential for detecting the oscillations, however, transient components in the signals cause false detections as well, motivating usage of models in order to remove the expected signals behavior.

Odgaard, Peter Fogh; Trangbæk, Klaus

2006-01-01

371

Ultraviolet Radiation Protection Methods (invited paper)  

International Nuclear Information System (INIS)

Exposure to solar UVR is widespread. Additionally, a small proportion of the population is exposed to artificial sources. There is a clear link between exposure to solar UVR and a range of adverse health effects. The acute and chronic exposure phenomena are different and, in terms of protection, both the measures and success rates will also be different. To reduce risk it is necessary to characterise fully the radiation source, understand the intermediate medium and the biological receptor and then develop appropriate exposure prevention strategies. Protection against occupational exposure to artificial sources should be approached using administrative and engineering control measures. Protective measures against solar UVR are still evolving. A significant decrease in risk can be achieved by changing behaviour through well-designed educational programmes. Personal protection is also important and effective protection is readily available. Avoidance of acute UVR effects and a decrease in skin cancer rates and mortality are the desirable long-term outcomes from such a programme. (author)

372

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)

373

The DNA/DNA hybridization method used to study radiation damages to DNA of wheat seedlings  

International Nuclear Information System (INIS)

The DNA/DNA hybridization method used to study radiation- induced damages to DNA has revealed a linear relationship between the dose of irradiation, in vitro, of DNA preparations from wheat seedlings and the relative value of a DNA damage. It was shown that the value of damages to DNA from the in vivo irradiated wheat seedlings is function of radiation dose (1-100 Gy). The applied method permits to detect, 24 h following irradiation, the nonrepaired and erroniously repaired damages to DNA nucleotides

374

Study of Silicon Pixel Sensors for Synchrotron Radiation Detection  

CERN Document Server

Hybrid pixel single-photon-counting detectors have been successfully employed and widely used in Synchrotron radiation X-ray detection. In this paper, the silicon pixel sensors for single X-ray photon detection, which operate in full-depletion mode have been studied. The pixel sensors were fabricated on 4-inch, N type, 320{\\mu}m thick, high-resistivity silicon wafers. The pixel sensors has a p+-in-n structure with varies of pixel size and gap size including guard-ring structures. Later, the pixel sensor was wire bonded to the ASIC circuits and tested for the performance of X-ray response in the synchrotron beam line (BSRF, 1W2B). From the S-curve scan, we could get the energy resolution and the linear properties between input energy and the equivalent generator amplitude. The pixel sensors we fabricated have a good energy linear and high count rate depending on the ASIC readout circuit. We get the 20% energy resolution above 10 keV photon energy via wire bonding. The energy resolution would get better if we b...

Li, Zhen-Jie; Hu, Ling-Fei; Liu, Peng; Yin, Hua-Xiang

2015-01-01

375

Large area silicon structures for nuclear radiation detection  

International Nuclear Information System (INIS)

Nuclear radiation detection requires large area detectors especially when surface contamination measurements must be done. This results from the low limit of alpha contamination acceptance rule: one particle per cm2 per minute (for population). The difficulties in using large area detectors arise from the associated high electronic noise. The noise is function of ?Ir, Cd, where Ir is the reverse current, and Cd, the capacity of the detector. It is possible to discriminate the noise in measuring circuits by cutting low energy response which, however, reduces the low energy efficiency of detection. Modern detector processing includes MOS (planar) technology with gettering techniques; so the reverse current (surface component and bulk generation) can be lower than 200 nA per cm2. Further noise reduction is obtained by a special matching of the input capacity of the preamplifier to detector capacity. The results presented in the paper refer to 2-10 cm2 - area spectrometric silicon detectors and alpha contamination detectors with an area of 2-30 cm2. (Author)

376

Echo detected EPR as a tool for detecting radiation-induced defect signals in pottery  

International Nuclear Information System (INIS)

Archaeological fragments of pottery have been investigated by using CW-EPR and Echo Detected EPR (EDEPR). EDEPR allows to remove the CW-EPR dominant Fe(III) background spectrum, hiding much weaker signals potentially useful for dating purpose. EDEPR spectra attributed to a methyl radical and to feldspar defects have been recorded at room and low temperature for an Iron Age cooking ware (700 B.C.). A study on the dependence of EDEPR intensity over absorbed dose on a series of ?-irradiated brick samples (estimated age of 562 ± 140 B.C.) has confirmed the potential efficacy of the proposed method for spotting defect signals out of the strong iron background. - Highlights: ? Fe(III) CW-EPR signals cover CW-EPR-detectable defects in ceramics. ? Echo detected EPR gets rid of Fe(III) signals, disclosing defect signals. ? Echo detected EPR detects defect signals even at relatively low doses.

377

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

378

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

379

Method of Object Detection for Mobile Robot  

OpenAIRE

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 ...

Surachai Panich

2010-01-01

380

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

381

A Method for Lung Boundary Detection  

OpenAIRE

In computerized analysis of chest radiographs is the detection of the lung field boundaries. Once the boundaries of the lung fields are identified, physiological measurements of the lung features are possible. The properties of the boundary are determined by edge detection along with suitable filter algorithms. The aim of proposed work is to develop an experimental system which segmented and analysis of the lung boundaries in chest X-ray images. This paper presents boundary detection of lung ...

Samir Kumar Bandyopadhyay

2012-01-01

382

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

383

Application of a rapid screening method to detect irradiated meat in Brazil  

Science.gov (United States)

Based on the enormous potential for food irradiation in Brazil, and to ensure free consumer choice, there is a need to find a convenient and rapid method for detection of irradiated food. Since treatment with ionising radiation causes DNA fragmentation, the analysis of DNA damage might be promising. In this paper, the DNA Comet Assay was used to identify exotic meat (boar, jacaré and capybara), irradiated with 60Co gamma rays. The applied radiation doses were 0, 1.5, 3.0 and 4.5 kGy. Analysis of the DNA migration enabled a rapid identification of the radiation treatment.

Villavicencio, A. L. C. H. A. L. C. H.; Mancini-Filho, J. J.; Delincée, H.

2000-03-01

384

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

385

Numerical methods for characterization of synchrotron radiation based on the Wigner function method  

Science.gov (United States)

Numerical characterization of synchrotron radiation based on the Wigner function method is explored in order to accurately evaluate the light source performance. A number of numerical methods to compute the Wigner functions for typical synchrotron radiation sources such as bending magnets, undulators and wigglers, are presented, which significantly improve the computation efficiency and reduce the total computation time. As a practical example of the numerical characterization, optimization of betatron functions to maximize the brilliance of undulator radiation is discussed.

Tanaka, Takashi

2014-06-01

386

Application of a rapid screening method to detect irradiated meat in Brazil  

International Nuclear Information System (INIS)

Complete text of publication follows. Based on the enormous potential for food irradiation in Brazil, and to ensure free consumer choice, there is a need to find a convenient and rapid method for detection of irradiated food. Since treatment with ionizing radiation causes DNA fragmentation, the analysis of DNA damage might be promising. In fact, DNA fragmentation measured in single cells by agarose gel electrophoresis - DNA Comet Assay - has shown to offer great potential as a rapid tool to detect whether a wide variety of foodstuffs has been radiation processed. However, more work is needed to exploit the full potential of this promising technique. In this paper, the DNA Comet Assay was used to identify exotic meat (boar, jacare and capybara), irradiated with 60Co gamma-rays. The applied radiation doses were 0, 1.5, 3.0 and 4.5 kGy. Analysis of the DNA migration enable a rapid identification of the radiation treatment

387

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

388

Plant abnormality detecting method and device therefor  

International Nuclear Information System (INIS)

The present invention always detects an abnormality of a plant at high accuracy irrespective of operation states of a plant. That is, various sensors are disposed at various portions in the plant for detecting abnormalities. A system for intaking plant operation states during plant operation on on-line is disposed in an abnormality detecting device independent of them. States of sound, temperature and vibration of the plant detected by each of the sensors are memorized corresponding to the plant operation states determined on on-line, so that detection of plant abnormality is corresponder to the plant operation states. Namely, an imaginary model for each of the sensors is provided, and the states of actual plant and signals from various kinds of sensors are compared with the plant operation state and signals of various sensors determined based on the imaginary model. If any contradiction occurs in the comparison, it is judged that abnormality is caused in the plant. (I.S.)

389

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

390

Curve fitting methods for solar radiation data modeling  

Energy Technology Data Exchange (ETDEWEB)

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 R{sup 2}. 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, E-mail: samsul-ariffin@petronas.com.my, E-mail: balbir@petronas.com.my; Singh, Balbir Singh Mahinder, E-mail: samsul-ariffin@petronas.com.my, E-mail: balbir@petronas.com.my [Department of Fundamental and Applied Sciences, Faculty of Sciences and Information Technology, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak Darul Ridzuan (Malaysia)

2014-10-24

391

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

392

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

393

Monte Carlo Radiation-Hydrodynamics With Implicit Methods  

Science.gov (United States)

We explore the application of Monte Carlo transport methods to solving coupled radiation-hydrodynamics (RHD) problems. We use a time-dependent, frequency-dependent, three-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 one-dimensional (non-relativistic) hydrodynamics solvers: a spherical Lagrangian scheme and a Eulerian Godunov solver. The gas-radiation energy coupling is treated implicitly, allowing us to take hydrodynamical time-steps that are much longer than the radiative cooling time. We validate the code and assess its performance using a suite of radiation hydrodynamical test problems, including ones in the radiation energy dominated regime. We also develop techniques that reduce the noise of the Monte Carlo estimated radiation force by using the spatial divergence of the radiation pressure tensor. The results suggest that Monte Carlo techniques hold promise for simulating the multi-dimensional RHD of astrophysical systems.

Roth, Nathaniel; Kasen, Daniel

2015-03-01

394

The All Terrain Bio nano Gear for Space Radiation Detection System  

International Nuclear Information System (INIS)

This paper discusses about the relevance of detecting space radiations which are very harmful and pose numerous health issues for astronauts. There are many ways to detect radiations, but we present a non-invasive way of detecting them in real-time while an astronaut is in the mission. All Terrain Bio-nano (ATB) gear system is one such concept where we propose to detect various levels of space radiations depending on their intensity and warn the astronaut of probable biological damage. A basic framework for radiation detection system which utilizes bio-nano machines is discussed. This radiation detection system is termed as 'radiation-responsive molecular assembly' (RMA) for the detection of space radiations. Our objective is to create a device which could detect space radiations by creating an environment equivalent to human cells within its structure and bio-chemically sensing the effects induced therein. For creating such an environment and further bio-chemically sensing space radiations bio-nano systems could be potentially used. These bio-nano systems could interact with radiations and signal based on the intensity of the radiations their relative biological effectiveness. Based on the energy and kind of radiation encountered, a matrix of signals has to be created which corresponds to a particular biological effect. The key advantage of such a design is its ability to interact with the radiation at e molecular scale; characterize its intensity based on energy depacterize its intensity based on energy deposition and relate it to the relative biological effectiveness based on the correspondence established through molecular structures and bond strengths of the bio-nano system

395

Radiation monitoring with NORM detection of vehicles at borders at stand-still  

International Nuclear Information System (INIS)

In this report the results of works performed under the Research Contract 12607/R0 are presented. All accomplished works can be divided into three parts: In the first part, the method is described used for radiation control of vehicles crossing customs and border check-points. At detection of the radioactivity in a vehicle, it is detained and the NORM materials and other radioactive materials are identified. The radiation monitor model was developed with realisation of the described vehicle control concept in it. This model was tested on-site on real vehicles crossing the customs check-point of the Republic of Uzbekistan. In the second part, based on the activities conducted in the first part, it was demonstrated that this method can be realised in practice for the purpose of its application at customs and border check-points for detection of nuclear and fissile materials with identification of radioactive isotopes in NORM-materials and other radioactive materials, as well as for decision making upon further possible transportation of such cargo. These results, showed in this report, were analysed and demonstrated that the 100x50 mm NaI(Tl)-crystal based scintillation detector is applicable, so that the identification capabilities become better when such detector is placed at 50 cm distance and closer to the vehicle. Other single crystal can be also used; however, one should take into account its geometry depending on the sizes of the crystal. In the third part, new ss of the crystal. In the third part, new sophisticated methods for radioactive materials detection were described, and the possibility for creation of radiation monitoring instrumentation based on the described above concept was demonstrated. (author)

396

Inertial confinement fusion method producing line source radiation fluence  

Science.gov (United States)

An inertial confinement fusion method in which target pellets are imploded in sequence by laser light beams or other energy beams at an implosion site which is variable between pellet implosions along a line. The effect of the variability in position of the implosion site along a line is to distribute the radiation fluence in surrounding reactor components as a line source of radiation would do, thereby permitting the utilization of cylindrical geometry in the design of the reactor and internal components.

Rose, Ronald P. (Peters Township, Washington County, PA)

1984-01-01

397

Method for calculating average radioactivity in radiation dosimetry  

International Nuclear Information System (INIS)

A simulation was conducted to calculate an average value of radioactivity within the wide-spread area where radiation sources are scattered. Calculations for arithmetic means and weighted means, obtained with changing the distribution of radiation sources, were compared. As a result, arithmetic means yielded favorable results; on the other hand, weighted means yielded smaller estimated values. In addition, an attempt was made to develop a new calculation method for determining errors of average values. (N.K.)

398

Alternative method of generation of Cerenkov radiation or shock wave  

CERN Document Server

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, A

1997-01-01

399

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)

400

Object detection methods for robot grasping: Experimental assessment and tuning  

OpenAIRE

In this work we address the problem of object detection for the purpose of object manipulation in a service robotics scenario. Several implementations of state-of-the-art object detection methods were tested, and the one with the best performance was selected. During the evaluation, three main practical limitations of current methods were identified in relation with long-range object detection, grasping point detection and automatic learning of new objects; and practical solutions are propose...

Rigual, Ferran; Ramisa, Arnau; Alenya? Ribas, Guillem; Torras Geni?s, Carme

2012-01-01

401

Efficient methods for radiation, scattering and propagation  

OpenAIRE

This document describes the research activities performed in the areas of antennas, scattering and wave propagation by several research groups belonging to different Universities located in Eastern Spain. These groups are working in the practical applications of efficient numerical electromagnetic methods within the frame of several research projects funded by private and public Spanish and European institutions. The main results obtained by these groups related to such topics, i.e. analysis ...

A?lvarez Melco?n, Alejandro; Coves Soler, A?ngela Mari?a; Andre?s Bou, Miguel Vicente; Bonia Esbert, V. E.

2006-01-01

402

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.

403

Radiation Detection System for Prevention of Illicit Trafficking of Nuclear and Radioactive Materials  

International Nuclear Information System (INIS)

Fixed radiation portal monitors (RPMs) deployed at border, seaport, airport and key traffic checkpoints have played an important role in preventing the illicit trafficking and transport of nuclear and radioactive materials. However, the RPM is usually large and heavy and can't easily be moved to different locations. These reasons motivate us to develop a mobile radiation detection system. The objective of this paper is to report our experience on developing the mobile radiation detection system for search and detection of nuclear and radioactive materials during road transport. Field tests to characterize the developed detection system were performed at various speeds and distances between the radioactive isotope (RI) transporting car and the measurement car. Results of measurements and detection limits of our system are described in this paper. The mobile radiation detection system developed should contribute to defending public's health and safety and the environment against nuclear and radiological terrorism by detecting nuclear or radioactive material hidden illegally in a vehicle

404

A Method for Lung Boundary Detection  

Directory of Open Access Journals (Sweden)

Full Text Available In computerized analysis of chest radiographs is the detection of the lung field boundaries. Once the boundaries of the lung fields are identified, physiological measurements of the lung features are possible. The properties of the boundary are determined by edge detection along with suitable filter algorithms. The aim of proposed work is to develop an experimental system which segmented and analysis of the lung boundaries in chest X-ray images. This paper presents boundary detection of lung using algorithms and results obtained quite satisfactory. This is tried to make a sharp distinction between the lung region and the exterior of the lung.

Samir Kumar Bandyopadhyay

2012-02-01

405

Detection and measurement of ionizing radiation by the Radioactive Waste Management Centre  

International Nuclear Information System (INIS)

The following topics are dealt with: Basic properties of radionuclides and selection of suitable detectors; radiation characteristics of sealed sources (radiation detection, dose rate measurement, surface contamination measurement, gamma spectroscopy); non-destructive analysis (segment gamma scanner, digital radiography); destructive analysis; radiation monitoring of humans and workplaces; and dosimetric monitoring of workplace surroundings and discharges. (orig.)

406

A gas chromatographic procedure to detect the radiation processing of chicken meat  

International Nuclear Information System (INIS)

A simple gas chromatographic procedure to detect the radiaton processing of chicken is presented. The method is based on the preferential formation of Cn-1 and Cn-2 alkanes and alkenes (n being the carbon number of the parent fatty acid), originating from cleavage of the lipids near the ester bond by the radiation treatment. Sample preparation was performed according to common pesticide analysis by fat extraction and separation of the hydrocarbons using florisil chromatography. Separated hydrocarbons are analysed by gas chromatography using a flame ionisation detector, and positive results are confirmed by gas chromatography-mass spectrometry. (orig.)

407

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

408

Inexpensive fusion methods for enhancing feature detection  

OpenAIRE

Recent successful approaches to high-level feature detection in image and video data have treated the problem as a pattern classification task. These typically leverage the techniques learned from statistical machine learning, coupled with ensemble architectures that create multiple feature detection models. Once created, co-occurrence between learned features can be captured to further boost performance. At multiple stages throughout these frameworks, various pieces of evidence can be fused ...

Wilkins, Peter; Adamek, Tomasz; O Connor, Noel E.; Smeaton, Alan F.

2007-01-01

409

Methods for climate change detection and attribution  

OpenAIRE

Detection and attribution (D&A) have played a central role within the assessment of the human influence on climate and within IPCC’s reports. Detection involves the statistical demonstration that a change has happened within climatic observations. Attribution consists in assessing the respective contributions of one or several causes to some observed change. Both require the use of climate model simulations, and are based on spatial or spatio temporal patterns of change. This paper provides...

Ribes, Aure?lien

2011-01-01

410

Detection of the Transverse Proximity Effect: Radiative Feedback from Bright QSOs  

Science.gov (United States)

Measuring the response of the intergalactic medium (IGM) to a blast of ionizing radiation allows one to infer the physical properties of the medium and, in principle, the lifetime and isotropy of the radiating source. The most sensitive such measurements can be made if the source of radiation is near the line of sight to a bright background QSO. We present results based on deep Keck HIRES observations of the QSO triplet KP 76, KP 77, and KP 78 at z~=2.5, with separations of 2'-3' on the plane of the sky. Using accurate systemic redshifts of the QSOs from near-IR spectroscopy, we quantify the state of the IGM gas in the proximity regions where the expected ionizing flux from the foreground QSOs exceeds that of the metagalactic background by factors of 10-200, assuming constant and isotropic emission. Based on the unusual ionization properties of the absorption systems with detected H I, C IV, and O VI, we conclude that the gas has been significantly affected by the UV radiation from the nearby QSOs. Aided by observations of the galaxy density near the foreground QSOs, we discuss several effects that may explain why the transverse proximity effect has eluded most previous attempts to detect it. Our observations suggest that the luminosities of KP 76 and KP 77 have remained comparable to current values over timescales of, respectively, ?t>25 Myr and 16 Myrindependent, less direct methods. There is no evidence that the UV radiation from either QSO was significantly anisotropic during these intervals. Based on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA and made possible by the generous financial support of the W. M. Keck Foundation.

Gonçalves, Thiago S.; Steidel, Charles C.; Pettini, Max

2008-04-01

411

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

412

Extragalactic filament detection with a layer smoothing method  

OpenAIRE

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 de...

Tugay, Anatoliy V.

2014-01-01

413

Tomographic apparatus and method for reconstructing planar slices from non-absorbed radiation  

International Nuclear Information System (INIS)

In a tomographic apparatus and method for reconstructing two-dimensional planar slices from linear projections of non-absorbed radiation useful in the fields of medical radiology, microscopy, and non-destructive testing, a beam of radiation in the shape of a fan is passed through an object lying in the same quasi-plane as the object slice and non-absorbtion thereof is recorded on oppositely-situated detectors aligned with the source of radiation. There is relative rotation between the source-detector configuration and the object within the quasi-plane. Periodic values of the detected radiation are taken, convolved with certain functions, and back-projected to produce a two-dimensional output picture on a visual display illustrating a facsimile of the object slice. A series of two-dimensional pictures obtained simultaneously or serially can be combined to produce a three dimensional portrayal of the entire object

414

Calibration method of radiation monitoring system at TQNPC  

International Nuclear Information System (INIS)

The calibration methods and calibration device for standard monitor of radioactive particulate, iodine, noble gas and so on are not yet set up at home. On consideration of the present situation of the radiation monitoring system at the Third Qinshan Nuclear Power Co. Ltd., we have studied the calibration method of these radiation monitoring instruments used for measuring the waste liquid, particulate, iodine and noble gas produced during the operation of nuclear reactor. Through the check against these instruments during the No. 202 and No. 103 overhaul, we got initially the method of the calibration and obtained the transfer coefficient of calibration when secondary solid sources are used for calibration. Through the testing and calibration, the credibility of the radiation monitoring system is enhanced. And at the same time, the problems existing in the calibration are discussed. (authors)

415

Identification of irradiated foods. I. Detection methods based on physical changes induced by irradiation in the food samples  

International Nuclear Information System (INIS)

Food processing by ionizing radiation is an emerging technology capable to extend the shelf-life of foods, to reduce their loses and to improve their hygienic quality. Because the process of food irradiation produces practically no change in appearance, shape, or texture of products, it is controlled mainly by administrative means. Therefore, there is a great interest in supplementing administrative control by developing detection methods for irradiated foods. In recent years, a number of analytical methods for detecting the radiation treatment of foods was developed. All foods can not be identified by a given method, but rather depending on the specific type of food, several methods are applicable. Depending on the detection parameter nature, the methods used may be based on physical, chemical and biological measurements. Physical methods - based on physical changes induced by radiation in food: viscosimetry, dielectric method, ESR spectroscopy, luminescence techniques. Chemical methods - based on chemical changes induced by irradiation in the main food components (proteins, lipids, nucleic acids): gas chromatography - mass spectrometry, liquid chromatography - gas chromatography, electrochemical sensor technique, high performance liquid chromatography, immunochemical detection method, and electrophoretic techniques. Biological methods - based on biological changes in radiation - processed food: microbiological tests (aerobic plate count, direct epi-fluorescence filt plate count, direct epi-fluorescence filter technique, Limulus Amoebocyte Lysate test-Gram negative bacterial count) and germination study. In this paper it is not possible to cover all the detection method, so only those which have been most developed will be discussed in detail. (authors)

416

Lanthanum halide nanoparticle scintillators for nuclear radiation detection  

Energy Technology Data Exchange (ETDEWEB)

Nanoparticles with sizes <10 nm were fabricated and characterized for their nanocomposite radiation detector properties. This work investigated the properties of several nanostructured radiation scintillators, in order to determine the viability of using scintillators employing nanostructured lanthanum trifluoride. Preliminary results of this investigation are consistent with the idea that these materials have an intrinsic response to nuclear radiation that may be correlated to the energy of the incident radiation.

Guss, Paul; Guise, Ronald [Remote Sensing Laboratory, P.O. Box 98521, M/S RSL-48, Las Vegas, Nevada 89193 (United States); Yuan Ding [National Security Technologies, LLC, Los Alamos Operations, P.O. Box 809, M/S LAO/C320, Los Alamos, New Mexico 87544 (United States); Mukhopadhyay, Sanjoy [Remote Sensing Laboratory-Andrews, Building 1783, Arnold Avenue Andrews AFB, Maryland 20762 (United States); O' Brien, Robert; Lowe, Daniel [University of Nevada, Las Vegas, 4505 S. Maryland Parkway, Las Vegas, Nevada 89154 (United States); Kang Zhitao; Menkara, Hisham [Georgia Tech Research Institute, 925 Dalney St., Atlanta, Georgia 30332 (United States); Nagarkar, Vivek V. [RMD, Inc., 44 Hunt Street, Watertown, Massachusetts 02472 (United States)

2013-02-14

417

ESR based detection method for irradiated dry fish, tomato soup powder and sweet-meats  

International Nuclear Information System (INIS)

Full text: Radiation Processing is increasingly being accepted as one of the most effective and economic method to treat agricultural and horticultural commodities for hygienization and disinfestation purposes and also in overcoming strict quarantine barriers in international trade. At present there is a growing concern about the presence of insecticides and pesticides and their residues in various foods, we consume. In view of this, irradiation, being a physical and cold process, emerges as the best bet towards having an uninterrupted supply of safe and quality food. The process has been endorsed as safe by several international and national bodies. A suitable detection method is however required to meet the basic requirements of consumers and law enforcement authorities, regulating the trade. Dried, sliced Pollack and File fishes were subjected to radiation dose of 4 kGy for elimination of coliforms and for improvement in quality standards during storage. Bones separated served as sample source for ESR based detection method of the radiation treatment. Bones with hard crystalline matrix served as trap for free radicals and facilitated evolution of an ESR based detection method. It showed a linear dose response curve at ?=2.0037, whereas, those from non-irradiated fish fillets failed to show any ESR signal. Re-irradiation helped in calculation of dose delivered to dried fishes. Sachets -containing tomato soup ingredients, including sugars exposed to 0.25 to 2 kGy galuding sugars exposed to 0.25 to 2 kGy gamma radiation doses for hygienization and quarantine purposes were used in the experiments. In-pack sugar crystals served as free radicals trap for ESR based detection method for radiation hygienized tomato soup powder. Similarly, it was observed that radiation hygienization of sugar bearing sweet-meats, like Peda (an evaporated milk preparation), Petha (a sugar syrup soaked vegetable preparation) and dry fruits like raisins could be detected using ESR. Suitable methodology was developed to detect radiation specific signals in minute amount of samples Thus, free radicals generated in fish bones and in sugar crystals of soups and sweet-meats were found to be specific to radiation dose and were fairly stable for analytical applications

418

Method and system for imaging a radiation source  

Science.gov (United States)

A method for imaging a radiation source, and a device that utilizes these methods that in one embodiment include the steps of: calculating at least one Compton cone of a first parameter of a radiation emission from information received from a sensor occurrence; and tracing this Compton cone on to a unit sphere having preselected characteristics using an estimated angular uncertainty to limit at least a portion of said tracing. In another embodiment of the invention at least two Compton cones are calculated and then intersected upon a predefined surface such as a sphere. These intersection points can then be iterated over a preselected series of prior events.

Myjak, Mitchell J. (Richland, WA) [Richland, WA; Seifert, Carolyn E. (Kennewick, WA) [Kennewick, WA; Morris, Scott J. (Kennewick, WA) [Kennewick, WA

2011-04-19

419

Properties and detection of ionizing radiation resulting from instantaneous fission and fission product mixture  

International Nuclear Information System (INIS)

The different types of ionizing radiation accompanying fission and mixtures of fission products, their activity, the determination of the age of fission products and the biological hazard of radiation caused by instantaneous fission are described. The possibility is described of detection, and of the dosimetry of ionizing radiation resulting from instantaneous fission and emitted by a mixture of fission products, the determination of the dose of neutron radiation, surface contamination, internal contamination and the contamination of water and foods. (J.P.)

420

Meshless method for radiation heat transfer in graded index medium  

Energy Technology Data Exchange (ETDEWEB)

Because ray goes along a curved path determined by the Fermat principle, curved ray tracing is very difficult and complex in graded index media. To avoid the difficult and complex computation of curved ray trajectories, a meshless local Petrov-Galerkin approach based on discrete-ordinate equations is developed to solve the radiative transfer problem in multi-dimensional absorbing-emitting-scattering semitransparent graded index media. A moving least square approximation is used to construct the shape function. Two particular test problems in radiative transfer are taken as examples to verify this meshless approach. The predicted temperature distributions and the dimensionless radiative heat fluxes are determined by the proposed method and compared with the other benchmark approximate solutions. The results show that the meshless local Petrov-Galerkin approach based on discrete-ordinate equations has a good accuracy in solving the radiative transfer problems in absorbing-emitting-scattering semitransparent graded index media. (author)

Liu, L.H. [School of Energy Science and Engineering, Harbin Institute of Technology, 92 West Dazhi Street, Harbin 150001 (China)

2006-01-15

421

Detection methods and performance criteria for genetically modified organisms.  

Science.gov (United States)

Detection methods for genetically modified organisms (GMOs) are necessary for many applications, from seed purity assessment to compliance of food labeling in several countries. Numerous analytical methods are currently used or under development to support these needs. The currently used methods are bioassays and protein- and DNA-based detection protocols. To avoid discrepancy of results between such largely different methods and, for instance, the potential resulting legal actions, compatibility of the methods is urgently needed. Performance criteria of methods allow evaluation against a common standard. The more-common performance criteria for detection methods are precision, accuracy, sensitivity, and specificity, which together specifically address other terms used to describe the performance of a method, such as applicability, selectivity, calibration, trueness, precision, recovery, operating range, limit of quantitation, limit of detection, and ruggedness. Performance criteria should provide objective tools to accept or reject specific methods, to validate them, to ensure compatibility between validated methods, and be used on a routine basis to reject data outside an acceptable range of variability. When selecting a method of detection, it is also important to consider its applicability, its field of applications, and its limitations, by including factors such as its ability to detect the target analyte in a given matrix, the duration of the analyses, its cost effectiveness, and the necessary sample sizes for testing. Thus, the current GMO detection methods should be evaluated against a