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1

Bayesian Methods for Radiation Detection and Dosimetry  

CERN Document Server

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

Groe, Peter G

2002-01-01

2

Recent developments in analytical detection methods for radiation processed foods  

International Nuclear Information System (INIS)

A short summary of the programmes of 'ADMIT' (FAO/IAEA) and the developments in analytical detection methods for radiation processed foods has been given. It is suggested that for promoting the commercialization of radiation processed foods and controlling its quality, one must pay more attention to the study of analytical detection methods of irradiated food

3

Apparatus and method for detecting gamma radiation  

Science.gov (United States)

A high efficiency radiation detector for measuring X-ray and gamma radiation from small-volume, low-activity liquid samples with an overall uncertainty better than 0.7% (one sigma SD). The radiation detector includes a hyperpure germanium well detector, a collimator, and a reference source. The well detector monitors gamma radiation emitted by the reference source and a radioactive isotope or isotopes in a sample source. The radiation from the reference source is collimated to avoid attenuation of reference source gamma radiation by the sample. Signals from the well detector are processed and stored, and the stored data is analyzed to determine the radioactive isotope(s) content of the sample. Minor self-attenuation corrections are calculated from chemical composition data.

Sigg, Raymond A. (Martinez, GA)

1994-01-01

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

Radionuclide detection by inductively coupled plasma mass spectrometry: A comparison of atomic and radiation detection method  

Energy Technology Data Exchange (ETDEWEB)

Radionuclide detection by mass spectrometric techniques offers inherent advantages over conventional radiation detection methods. Since radionuclides decay at variable rates (half-lives) and via various nuclear transformations (i.e. emission of alpha, beta, and/or gamma radiation) their determination via radiation detection depends not only on decay systematics but also on detector technology. Radionuclide detection by direct atom measurement, however, is dependent only on technique sensitivity and is indifferent to decay mode. Evaluation of inductively coupled plasma mass spectrometry (ICP/MS) indicates this method to be superior conventional radiation detection techniques for many radionuclides. This work discusses factors which influence detection by both methods. Illustrative applications of ICP/MS to the ultra-trace determination of several radionuclides, including {sup 129}I, are presented. 20 refs., 6 figs., 1 tab.

Smith, M.R.; Wyse, E.J.; Koppenaal, D.W.

1991-04-01

6

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

International Nuclear Information System (INIS)

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

7

Detection of HCMV infection of radiation workers with rapid-ELISA method  

International Nuclear Information System (INIS)

Objective: To establish a rapid method to detect HCMV with ELISA, and to study the infection conditions of radiation workers. Methods: using routine ELISA except adding 3% PEG to dilution solution to accelerate the reaction of antibody to antigen, the HCMV-IgG and HCMV-IgM in the serum of radiation workers were detected. Results: The total positive rate in 514 radiation workers in Jinan is 96.69%, of which 94.16% is latent infection, 0.19% is primary infection, 2.34% is relapse infection, and active infection rate is 2.53%. Conclusion: Radiation workers have certain risk to suffer from infection of HCMV which should delt with seriously. (authors)

8

Radiation detection method and system using the sequential probability ratio test  

Science.gov (United States)

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

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

2007-07-17

9

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

10

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

11

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

International Nuclear Information System (INIS)

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

12

Biological detection of low radiation doses by combining results of two microarray analysis methods  

Science.gov (United States)

The accurate determination of the biological effects of low doses of pollutants is a major public health challenge. DNA microarrays are a powerful tool for investigating small intracellular changes. However, the inherent low reliability of this technique, the small number of replicates and the lack of suitable statistical methods for the analysis of such a large number of attributes (genes) impair accurate data interpretation. To overcome this problem, we combined results of two independent analysis methods (ANOVA and RELIEF). We applied this analysis protocol to compare gene expression patterns in Saccharomyces cerevisiae growing in the absence and continuous presence of varying low doses of radiation. Global distribution analysis highlights the importance of mitochondrial membrane functions in the response. We demonstrate that microarrays detect cellular changes induced by irradiation at doses that are 1000-fold lower than the minimal dose associated with mutagenic effects. PMID:14722227

Mercier, G.; Berthault, N.; Mary, J.; Peyre, J.; Antoniadis, A.; Comet, J.-P.; Cornuejols, A.; Froidevaux, C.; Dutreix, M.

2004-01-01

13

Evaluation of phase sensitive detection method and Si avalanche photodiode for radiation thermometry  

International Nuclear Information System (INIS)

We report the evaluation of Si avalanche photodiodes (APDs) for use in radiation thermometry as an alternative to Si photodiodes. We compared their performance when operated under phase sensitive detection (PSD), where the signal is modulated, and direct detection (DD) methods. A Si APD was compared with a Si photodiode with reference black body temperatures of 275 to 600°C, in terms of the mean output voltage and signal-to-noise ratio (SNR), measured at different APD gain values. We found that using both PSD and DD methods, the high internal gain of the Si APD achieved a lower minimum detection temperature in order to satisfy a specific minimum output voltage of the detector-preamplifier combination employed. The use of PSD over DD for the Si APD allowed for improved performance of the thermometer, with a lower minimum measurable temperature, as well as improvement in the SNR. For instance we found that at 350°C, the Si APD biased at 150 V using PSD can provide ? 88 times enhancement in the system SNR over that of a Si photodiode using DD. A corresponding temperature error of ±0.05°C was achieved using the APD with PSD compared to an error of ±2.75°C measured using the Si photodiode with DD.

14

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

15

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

16

Counterbalanced radiation detection device  

International Nuclear Information System (INIS)

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

17

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

18

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)

19

Gravitational radiation detection  

International Nuclear Information System (INIS)

Resonant gravitational wave detectors and related data analysis are studied. Different forms (strain amplitude) of the equation of motion for a medium responding to a gravitational wave are discussed in relation to the detection of such waves. Utilizing ''Bayesian techniques'' an optimal method for data analysis is developed. Noise and filter theory is reviewed. It is seen that the ''Bayesian techniques'' integrates filter theory and data analysis, providing both filter properties and optimal methods for integrating the data. (In particular the method leads to a nonthreshold type of analysis, and ''looks for'' correlation between two detectors without the use of time delay). Expression for optimal sensitivity (and filters) of detector systems are given, including the limit of perfect sensors and electronics. The signal to noise ratio in terms of the spectral power of the gravitational radiation is derived. Long baseline interferometry is discussed. A computer program simulating a pair of Weber type detectors is developed to study different approaches to data analysis

20

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

 
 
 
 
21

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.)

22

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

International Nuclear Information System (INIS)

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

23

Examination of stochastic methods for determination of detection limits of nuclear radiation measuring techniques  

International Nuclear Information System (INIS)

The empirical study examined by means of statistical approximation tests to what extent the Poisson distribution law or the negative binomial distribution, the normal or the logarithmic normal distribution can suitably interpret nuclear radiation measurements. Whereas the data obtained by counting radiation measurement without sample preparation in general did not reject the hypothesis of Poisson's distribution governing the processes, measurements using prepared, and particularly intensively prepared, samples as a rule did not confirm applicability of this approach, but rather indicated applicability of the hypothesis of a negative binomial distribution. The study presents formulae for the calculation of detection limits and identification limits on the basis of assuming a negative binomial distribution. (orig./DG)

24

Electrets for ? radiation detection  

International Nuclear Information System (INIS)

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

25

Radiation detection and measurement  

International Nuclear Information System (INIS)

The book is a complete, clear and up-to-date text that provides a basic review of instruments and methods of ionizing radiation. The text covers detailed discussion of all detector types introductory discussions of radiation sources, interactions, and counting statistics functional analysis of the electronics and pulse processing aspects of radiation detectors in instrumentation systems and consideration of shielding and background potentially vital in low-level counting. A total of 350 figures and approximately 900 references to current scientific literature is included. The book is largely intended as a textbook for a junior/senior or first-year graduate course in nuclear instrumentation and radiation measurements

26

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

International Nuclear Information System (INIS)

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.

27

Coherent radiation detecting apparatus  

International Nuclear Information System (INIS)

This patent describes an apparatus for detecting the presence of coherent radiation in the presence of non-coherent ambient radiation which consists of: an unequal optical path length interferometer of the type in which portions of the radiation impinging on the interferometric component are caused to be recombined after travelling two different optical paths; the optical paths differing in length by an amount substantially greater than the coherence length of the non-coherent radiation but substantially less than the coherence length of the coherent radiation; the unequal optical path length interferometric component comprising a crystalline cell having anisotropic properties; means for applying an ultrasonic sound wave to the crystalline cell to vary the effective index of refraction of the crystalline cell in a preselected systematic manner; and means for detecting the intensity of the recombined portions and producing a signal representative thereof, the signal having a variable component caused by the varying constructive and destructive interference of the recombined coherent radiation components, while the recombined non-coherent ratiation components produce only a substantially steady background signal

28

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

29

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)

30

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

International Nuclear Information System (INIS)

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

31

Radiation detection system  

International Nuclear Information System (INIS)

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

32

Data derandomizer and method of operation for radiation imaging detection systems  

International Nuclear Information System (INIS)

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

33

Radiation Detection from Fission  

Energy Technology Data Exchange (ETDEWEB)

This report briefly describes the neutrons and gamma rays emitted in fission, 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. The brief descriptions are supplemented by reference.

Mihalczo, J.

2004-11-17

34

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

35

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)

36

Control method and device for automatic drift stabilization in radiation detection  

International Nuclear Information System (INIS)

In the automatic control circuit individual electron peaks in the detectors, e.g. NaI crystals or proportional counters, are used. These peaks exhibit no drift dependence; they may be produced in the detectors in different ways. The control circuit may be applied in nuclear radiation measurement techniques, photometry, gamma cameras and for measuring the X-ray fine structure with proportional counters. (DG)

37

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

Directory of Open Access Journals (Sweden)

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

Ravichandran R

2007-01-01

38

Developments in radiation detection  

International Nuclear Information System (INIS)

The effectiveness of a radiation-protection programme must be checked by an adequate monitoring system. A recent symposium organized by the IAEA reviewed developments in radiation detectors that can be used to measure different types of radiation and in biological indicators of radiation dose which could become of real value. (author)

39

A method and apparatus for converting a liquid scintillation counter for beta detection into a gamma radiation counter  

International Nuclear Information System (INIS)

Description is given of a flask for measuring the gamma radiation of samples in a scintillation counter intended for beta radiation detection. That flask is provided with a scintillator made of a mineral crystal of generally cylindrical shape, comprising a sample-receiving central chamber, the volume of which is from about 4 to 15 cubic centimeters. Sais scintillator is sealingly enclosed in a protective container with a light transparent cylindrical outer face. The flask height is less than 7cm and its diameter less than 3cm. This can be applied to converting liquid scintillation counters for beta radiation into gamma radiation counters

40

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

 
 
 
 
41

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)

42

A Method Based on Radiative Cooling for Detecting Structural Changes in Undercooled Metallic Liquids  

Science.gov (United States)

We introduce a structure-sensitive parameter for undercooled melts which can be measured in containerless processing experiments. We have established that the ratio, R(T), of hemispherical total emissivity epsilon(sub T)(T) to constant-pressure specific heat c(sub p)(T) can serve as an indicator which is sensitive to any changes in short range atomic order in undercooled metallic melts. R(T) (triple bonds) epsilon(sub T)(T)/c(sub p)(T) values for nickel, zirconium, and silicon have been obtained using the high temperature electrostatic levitator while the levitated melts were undergoing purely radiative cooling into the deeply undercooled region. R(T) plots for undercooled liquid nickel and zirconium indicate no significant change in short-range structure from their melting temperatures to 15% undercooling. In contrast, liquid silicon shows marked short-range structural changes beginning above its melting temperature and extending throughout the undercooled region. The short-range structure of liquid silicon is related to the highly-directional covalent bonding which characterizes its solid form. The nickel and zirconium data show that epsilon(sub T) varies linearly with T, in support of metal emissivity theories.

Rulison, Aaron J.; Rhim, Won-Kyu

1995-01-01

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

Biological detection of low radiation doses by combining results of two microarray analysis methods  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The accurate determination of the biological effects of low doses of pollutants is a major public health challenge. DNA microarrays are a powerful tool for investigating small intracellular changes. However, the inherent low reliability of this technique, the small number of replicates and the lack of suitable statistical methods for the analysis of such a large number of attributes (genes) impair accurate data interpretation. To overcome this problem, we combined results of two independent a...

Mercier, G.; Berthault, N.; Mary, J.; Peyre, J.; Antoniadis, A.; Comet, J. -p; Cornuejols, A.; Froidevaux, C.; Dutreix, M.

2004-01-01

45

Electronics for radiation detection  

CERN Document Server

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

2011-01-01

46

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

International Nuclear Information System (INIS)

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

47

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

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

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

50

Detection of nuclear radiations  

International Nuclear Information System (INIS)

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

51

Detection methods of irradiated foodstuffs  

International Nuclear Information System (INIS)

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)

52

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)

53

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

54

Radiation treatment of crude drugs. Development of suitable methods of detection. Strahlenbehandlung von Arzneidrogen. Entwicklung geeigneter Nachweismethoden  

Energy Technology Data Exchange (ETDEWEB)

It may be necessary to reduce microbiological contamination of crude drugs (medicinal plants or their parts like roots, leaves, flowers). This can be done by treating the drugs with ionizing radiation. Meethods for detection of such an irradiation were developed. It could be pointed out that measurements of luminescence, viscosity and electron spin resonance were suitable for specific drugs, but not for all drugs. (orig.).

Stock, A.; Gebhardt, G.; Helle, N.; Schuettler, C.; Boegl, K.W. (BGA, Berlin (Germany). Inst. fuer Sozialmedizin und Epidemiologie)

1992-09-01

55

Cherenkov radiation used in detection of some beta emitters  

International Nuclear Information System (INIS)

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

56

Fuel failure detection method  

International Nuclear Information System (INIS)

A method of detection of small amounts of radioactive iodine in the presence of large amounts of radioactive sodium is claimed. The method can be used for fuel failure detection in a sodium-cooled FBR type reactor. (RW/AK)

57

Origin, characteristics and detection of nuclear radiation  

International Nuclear Information System (INIS)

The report is an introduction into the physical principles of radiation protection. After a brief summary of the most significant experimental results and data on the atomic structure of the matter and after explaining the principles of atomic and nuclear structure, radioactive decay and its laws are dealt with. This is followed by a representation of the characteristics of nuclear radiation, its interaction with the matter as well as the biological effects. After a description of the measurement units for radioactivity and doses the most inportant methods for radiation detection and the principles of how detectors function are explained. (ORU/LN)

58

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

59

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

60

Radiation Detection for Active Interrogation of HEU  

Energy Technology Data Exchange (ETDEWEB)

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.

Mihalczo, J.T.

2004-12-09

 
 
 
 
61

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.)

62

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)

63

Detection of radiation treatment of food  

International Nuclear Information System (INIS)

A list of foodstuffs is given whose irradiation is permitted in at least one country, as are the purpose of irradiation and permitted doses. A survey is given of the methods used for the detection of radiation treatment and the determination of the applied dose. The principles of chemical methods applied for the testing of irradiated meat, fats, fish and marine products, fruit, mushrooms, sugars, cereals and potatoes are tabulated. (M.D.)

64

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

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

Cellular telephone-based radiation detection instrument  

Energy Technology Data Exchange (ETDEWEB)

A network of radiation detection instruments, each having a small solid state radiation sensor module integrated into a cellular phone for providing radiation detection data and analysis directly to a user. The sensor module includes a solid-state crystal bonded to an ASIC readout providing a low cost, low power, light weight compact instrument to detect and measure radiation energies in the local ambient radiation field. In particular, the photon energy, time of event, and location of the detection instrument at the time of detection is recorded for real time transmission to a central data collection/analysis system. The collected data from the entire network of radiation detection instruments are combined by intelligent correlation/analysis algorithms which map the background radiation and detect, identify and track radiation anomalies in the region.

Craig, William W. (Pittsburg, CA); Labov, Simon E. (Berkeley, CA)

2011-06-14

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

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

Energy Technology Data Exchange (ETDEWEB)

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 {sup 60}Co 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.

Araujo, M.M.; Duarte, R.C.; Silva, P.V. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Centro de Tecnologia das Radiacoes, Laboratorio de Deteccao de Alimentos Irradiados, Cidade Universitaria, Av. Prof. Lineu Prestes 2242, Butanta Zip Code 05508-000 Sao Paulo (Brazil); Marchioni, E. [Laboratoire de Chimie Analytique et Sciences de l' Aliment (UMR 7512), Faculte de Pharmacie, Universite Louis Pasteur, 74, route du Rhin, F-67400 Illkirch (France); Villavicencio, A.L.C.H. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Centro de Tecnologia das Radiacoes, Laboratorio de Deteccao de Alimentos Irradiados, Cidade Universitaria, Av. Prof. Lineu Prestes 2242, Butanta Zip Code 05508-000 Sao Paulo (Brazil)], E-mail: villavic@ipen.br

2009-07-15

70

Detecting radiation with your smartphone  

CERN Multimedia

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

71

Radiation delivery system and method  

Energy Technology Data Exchange (ETDEWEB)

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

72

10 CFR 39.33 - Radiation detection instruments.  

Science.gov (United States)

...2010-01-01 false Radiation detection instruments. 39.33 Section...Equipment § 39.33 Radiation detection instruments. (a) The...instrument capable of detecting beta and gamma radiation at...calibrated and operable radiation detection instruments sensitive...

2010-01-01

73

Exoplanet Detection: Transit Method  

Science.gov (United States)

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

Belloni, Mario

2010-06-29

74

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

International Nuclear Information System (INIS)

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

75

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

International Nuclear Information System (INIS)

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

76

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

77

Device for the detection of ionizing radiation  

International Nuclear Information System (INIS)

This patent deals with the detection of ionizing radiation and in particular such radiation as is used in tomography. This radiation is characterized by the simultaneous exiting from a body as a series of straight beams in a common plane. The detector can be either a semiconductor diode or a diode used in conjunction with a scintillator crystal

78

Methods of cadmium detection  

International Nuclear Information System (INIS)

A variety of analytical methodologies of varying complexity and applicability pertinent to the determination of cadmium in organic and inorganic environmental matrices are discussed in this chapter: flame atomic absorption spectrometry (FAAS), flame atomic absorption spectrometry with solvent extraction (SEFAAS), electrothermal (graphite furnace) atomic absorption spectrometry (EAAS), inductively coupled plasma atomic emission spectrometry (ICPAES), anodic stripping voltammetry (ASV), instrumental neutron activitation analysis (INAA), inductively coupled plasma mass spectrometry (ICPMS), and spark source mass spectrometry (SSMS). Factors such as sampling, sample storage, and the role of laboratory-ware and reagents and the analyst as sources of contamination are of underlying importance to all analytical methods; in addition, sample decomposition and/or analyte concentration are essential steps for all techniques with the exception of INAA and perhaps SSMS and ICPMS. In selecting a particular technique, consideration of the following technical and operational characteristics can be useful: multielement capability: detection limit; sample preparation requirements and hence analytical throughout; spectral, physical, and chemical interferences; precision and accuracy; and operational expertise and cost, with weighting and judgmental factors at the discretion of the analyst and establishment. Detection limits on a sample basis range from 0.05 and 0.5 ?g/g for ASV and EAAge from 0.05 and 0.5 ?g/g for ASV and EAAS, respectively, to 100 ?g/g for ICPAES, permitting most of the techniques to be applicable to the measurements of the cadmium in solid aquatic materials with the exception of freshwater fish

79

Method for microbeam radiation therapy  

Science.gov (United States)

A method of performing radiation therapy on a patient, involving exposing a target, usually a tumor, to a therapeutic dose of high energy electromagnetic radiation, preferably X-ray radiation, in the form of at least two non-overlapping microbeams of radiation, each microbeam having a width of less than about 1 millimeter. Target tissue exposed to the microbeams receives a radiation dose during the exposure that exceeds the maximum dose that such tissue can survive. Non-target tissue between the microbeams receives a dose of radiation below the threshold amount of radiation that can be survived by the tissue, and thereby permits the non-target tissue to regenerate. The microbeams may be directed at the target from one direction, or from more than one direction in which case the microbeams overlap within the target tissue enhancing the lethal effect of the irradiation while sparing the surrounding healthy tissue.

Slatkin, Daniel N. (Sound Beach, NY); Dilmanian, F. Avraham (Yaphank, NY); Spanne, Per O. (Shoreham, NY)

1994-01-01

80

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

 
 
 
 
81

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

82

CLOUD DETECTION METHODS – A REVIEW  

Directory of Open Access Journals (Sweden)

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

B.RAMESH

2013-04-01

83

Radiation Detection Center on the Front Lines  

Energy Technology Data Exchange (ETDEWEB)

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&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 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.''

Hazi, A

2005-09-20

84

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 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.''

85

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

International Nuclear Information System (INIS)

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

86

Main Achievements 2003-2004 - Interdisciplinary Research - Radiation detection methods for health, earth and environmental sciences - Thermoluminescence (TL) detectors  

International Nuclear Information System (INIS)

The IFJ has over 35 years of experience in the development, production and application of new types of thermoluminescence (TL) detectors, particularly LiF:Mg,Ti and LiF:Mg,Cu,P. Over 600,000 LiF detectors produced at the IFJ PAN are routinely applied in dosimetry services and hospitals in 30 countries. The current research in the field of thermoluminescence concentrates in space dosimetry and novel 2-dimensional detectors for medical applications. The space project (named Matroshka), organized by the European Space Agency, is one of the most ambitious dosimetry experiments in space. In February 2004 an anatomical model of the human body (a humanoid phantom), equipped with over 3500 dedicated thermoluminescent detectors (TLD), developed and produced at IFJ and tested at the Chiba heavy ion accelerator in Japan, was installed outside the International Space Station (ISS) to determine the cosmic radiation doses absorbed in human organs, which would be experienced by astronauts in open space. The phantom will remain in space for one year, after which the detectors will be returned to the IFJ for analysis

87

Detection of foods preserved by radiation  

International Nuclear Information System (INIS)

Analytical methods suitable for the detection of irradiated foods are reviewed. The detection methods are classified as physical, chemical, microbiological and biological, respectively. Reliability, robustness, sensitivity, accuracy and simplicity of the each method are discussed. (author)

88

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

89

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.

90

Radiation, ionization, and detection in nuclear medicine  

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-08-01

91

Physics and engineering of radiation detection  

CERN Document Server

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

Ahmed, Syed Naeem

2007-01-01

92

Detection methods for irradiated food  

International Nuclear Information System (INIS)

The detection methods for irradiated food are presented. There is no general method applicable to all foods and thus a range of tests based on physical, chemical, microbiological and biological alterations in food are being developed. The suitable detection method can help to disseminate the application of irradiation technique in the food industry. (author)

93

Flaw detection methods reviewed  

International Nuclear Information System (INIS)

In-service inspection aims to detect metallurgical flaws which could constitute a safety hazard or cause costly failures. The growth of nuclear in-service inspection which has stimulated developments in all of the accepted non-destructive testing techniques and particularly in ultrasonics is reviewed. The performance of in-service inspection, choice of procedures, and how effective they are in detecting significant flaws are discussed. A brief description is given of the techniques available; dye penetrant, magnetic particle inspection, radiography, ultrasonics, eddy currents and acoustic emission. (U.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

Radiation detection and measurement student solutions manual  

CERN Document Server

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

Wehe, David K

2012-01-01

96

Detection and measurement of ionizing radiation  

International Nuclear Information System (INIS)

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

97

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

98

Methods of DNA methylation detection  

Science.gov (United States)

The present invention provides for methods of DNA methylation detection. The present invention provides for methods of generating and detecting specific electronic signals that report the methylation status of targeted DNA molecules in biological samples.Two methods are described, direct and indirect detection of methylated DNA molecules in a nano transistor based device. In the direct detection, methylated target DNA molecules are captured on the sensing surface resulting in changes in the electrical properties of a nano transistor. These changes generate detectable electronic signals. In the indirect detection, antibody-DNA conjugates are used to identify methylated DNA molecules. RNA signal molecules are generated through an in vitro transcription process. These RNA molecules are captured on the sensing surface change the electrical properties of nano transistor thereby generating detectable electronic signals.

Maki, Wusi Chen (Inventor); Filanoski, Brian John (Inventor); Mishra, Nirankar (Inventor); Rastogi, Shiva (Inventor)

2010-01-01

99

Electrets for beta radiation detection  

International Nuclear Information System (INIS)

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

100

Method for detecting solidifacation in a mixed phase container  

International Nuclear Information System (INIS)

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

 
 
 
 
101

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

102

Integral pulse discharge method for radiation dose measurement  

International Nuclear Information System (INIS)

The dose measurement is studied in a radiation field in which the intensity of radiation changes rapidly with time. This paper introduces an integral pulse discharge method which may be used as the basic measurement method. A detection system for operating in ?, X, neutron mixed field is designed

103

? radiation detection with ultra thin thermoluminescent samples  

International Nuclear Information System (INIS)

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

104

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

105

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

106

Method for Detection of Mycoplasma.  

Science.gov (United States)

A method is described for detecting mycoplasma infection in a sample by contacting the sample with labeled oligonucleotides, then measuring incorporation (if any) of the label into mycoplasma RNA. One preferred embodiment of the invention relates to a met...

D. Geselowitz, L. Neckers, L. Olsen

1992-01-01

107

Method and device for detecting radiatons  

International Nuclear Information System (INIS)

The method consists in fabricating an MOS transistor comprising a drain region and a source region separated from each other by a bulk region of opposite doping type relative to the first two regions, in delivering the radiation to be detected into the carrier-collection region of the MOS transistor, in leaving the bulk region at a floating potential and in collecting the drain-source current of the transistor

108

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

109

Detection system built from commercial integrated circuits for real-time measurement of radiation dose and quality using the variance method  

International Nuclear Information System (INIS)

A small, specialised amplifier using commercial integrated circuits (ICs) was developed to measure radiation dose and quality in real time using a microdosimetric ion chamber and the variance method. The charges from a microdosimetric ion chamber, operated in the current mode, were repeatedly collected for a fixed period of time for 20 cycles of 100 integrations, and processed by this specialised amplifier to produce signal pulse heights between 0 and 10 V. These signals were recorded by a multi-channel analyser coupled to a computer. FORTRAN programs were written to calculate the dose and dose variance. The dose variance produced in the ion chamber is a microdosimetric measure of radiation quality. Benchmark measurements of different brands of ICs were conducted. Results demonstrate that this specialised amplifier is capable of distinguishing differences of radiation quality in various high-dose-rate radiation fields including X rays, gamma rays and mixed neutron-gamma radiation from the research reactor at Texas A and M Univ. (authors)

110

Composite scintillators for detection of ionizing radiation  

Science.gov (United States)

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

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

2010-12-28

111

77 FR 55199 - Radiation Detection Technologies, Inc.  

Science.gov (United States)

Notice is hereby given to an intent to grant to Radiation Detection Technologies, Inc., of Manhattan, Kansas, an exclusive license to practice the inventions described in U.S. Patent No. 6,545,281, entitled ``Pocked Surface Neutron Detector''. The invention is owned by the United States of America, as represented by the U.S. Department of Energy...

2012-09-07

112

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

113

Measuring element for the detection and determination of radiation doses of gamma radiation and neutrons  

International Nuclear Information System (INIS)

A measuring element detects and proves both gamma and neutron radiation. The element includes a photoluminescent material which stores gamma radiation and particles of arsenic and phosphorus embedded in the photoluminescent material for detecting neutron radiation. (U.S.)

114

Radiation techniques for detection of explosives  

International Nuclear Information System (INIS)

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

115

Detection of alpha radiation in a beta radiation field  

Science.gov (United States)

An apparatus and method for detecting alpha particles in the presence of high activities of beta particles utilizing an alpha spectrometer. The apparatus of the present invention utilizes a magnetic field applied around the sample in an alpha spectrometer to deflect the beta particles from the sample prior to reaching the detector, thus permitting detection of low concentrations of alpha particles. In the method of the invention, the strength of magnetic field required to adequately deflect the beta particles and permit alpha particle detection is given by an algorithm that controls the field strength as a function of sample beta energy and the distance of the sample to the detector.

Mohagheghi, Amir H. (Albuquerque, NM); Reese, Robert P. (Edgewood, NM)

2001-01-01

116

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.)

117

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)

118

Radiation detection technology assessment program (RADTAP)  

International Nuclear Information System (INIS)

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

119

Space Radiation Transport Methods Development  

Science.gov (United States)

Improved spacecraft shield design requires early entry of radiation constraints into the design process to maximize performance and minimize costs. As a result, we have been investigating high-speed computational procedures to allow shield analysis from the preliminary design concepts to the final design. In particular, we will discuss the progress towards a full three-dimensional and computationally efficient deterministic code for which the current HZETRN evaluates the lowest order asymptotic term. HZETRN is the first deterministic solution to the Boltzmann equation allowing field mapping within the International Space Station (ISS) in tens of minutes using standard Finite Element Method (FEM) geometry common to engineering design practice enabling development of integrated multidisciplinary design optimization methods. A single ray trace in ISS FEM geometry requires 14 milliseconds and severely limits application of Monte Carlo methods to such engineering models. A potential means of improving the Monte Carlo efficiency in coupling to spacecraft geometry is given in terms of reconfigurable computing and could be utilized in the final design as verification of the deterministic method optimized design.

Wilson, J. W.; Tripathi, R. K.; Qualls, G. D.; Cucinotta, F. A.; Prael, R. E.; Norbury, J. W.; Heinbockel, J. H.; Tweed, J.

2002-01-01

120

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

 
 
 
 
121

Cellular telephone-based wide-area radiation detection network  

Energy Technology Data Exchange (ETDEWEB)

A network of radiation detection instruments, each having a small solid state radiation sensor module integrated into a cellular phone for providing radiation detection data and analysis directly to a user. The sensor module includes a solid-state crystal bonded to an ASIC readout providing a low cost, low power, light weight compact instrument to detect and measure radiation energies in the local ambient radiation field. In particular, the photon energy, time of event, and location of the detection instrument at the time of detection is recorded for real time transmission to a central data collection/analysis system. The collected data from the entire network of radiation detection instruments are combined by intelligent correlation/analysis algorithms which map the background radiation and detect, identify and track radiation anomalies in the region.

Craig, William W. (Pittsburg, CA); Labov, Simon E. (Berkeley, CA)

2009-06-09

122

Chemical agent detection method and apparatus  

International Nuclear Information System (INIS)

The method of detecting predetermined organic halogen compounds in a gas comprising the steps of directing a sample of said gas into a reaction chamber containing immobilized therein a halogen compound in which the halogen constituent is radioactive, providing environmental conditions in said chamber to promote a chemical reaction whereby said radioactive constituent forms a mobile compound with a constituent of said organic halogen compound, and passing said sample including any of said mobile compound generated out of said reaction chamber and into the presence of a radiation detector

123

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

124

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

125

Radiation containment apparatus and method  

International Nuclear Information System (INIS)

A radiation containment apparatus comprising a source of radiation having an area from which radiation is emitted, and a vinyl polymer sheet generally arranged about the area from which radiation is emitted in a manner so as to receive the radiation. The source of radiation is a cathode ray tube. The vinyl polymer sheet is a clear sheet of polyvinyl chloride. An enclosure made up of polyvinyl chloride sheets generally surround the source of radiation. A plurality of fasteners are arranged about the periphery of the cathode ray tube so as to receive the polyvinyl chloride sheet. The polyvinyl chloride sheet also includes notches about the outer edges for engaging the fasteners on the cathode ray tube

126

Stand-off detection of mixed radiation fields  

Science.gov (United States)

The goal of this study is to present unconventional detection and imaging principles which may lead to novel detection and characterization methodologies for standoff detection of radiation. While there currently are a number of effective technologies and methodologies for nuclear detection based on direct and indirect-ionization detector architectures operating on radiation counting techniques, the problem of detecting nuclear radiation at significant standoff distances remains one of the most difficult and most important challenges. The phenomenology of alternative signatures, a physical algorithm aimed to assess remotely biological hazards of nuclear radiation, and the design of efficient standoff detection architectures are presented.

Giakos, G. C.

2008-03-01

127

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

128

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

129

Calibration method for video and radiation imagers  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-07-05

130

Electromagnetic Methods of Lightning Detection  

Science.gov (United States)

Both cloud-to-ground and cloud lightning discharges involve a number of processes that produce electromagnetic field signatures in different regions of the spectrum. Salient characteristics of measured wideband electric and magnetic fields generated by various lightning processes at distances ranging from tens to a few hundreds of kilometers (when at least the initial part of the signal is essentially radiation while being not influenced by ionospheric reflections) are reviewed. An overview of the various lightning locating techniques, including magnetic direction finding, time-of-arrival technique, and interferometry, is given. Lightning location on global scale, when radio-frequency electromagnetic signals are dominated by ionospheric reflections, is also considered. Lightning locating system performance characteristics, including flash and stroke detection efficiencies, percentage of misclassified events, location accuracy, and peak current estimation errors, are discussed. Both cloud and cloud-to-ground flashes are considered. Representative examples of modern lightning locating systems are reviewed. Besides general characterization of each system, the available information on its performance characteristics is given with emphasis on those based on formal ground-truth studies published in the peer-reviewed literature.

Rakov, V. A.

2013-11-01

131

Exoplanet Detection: Radial Velocity Method  

Science.gov (United States)

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

Belloni, Mario

2010-06-29

132

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

133

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

134

Radiation measuring device for use in fuel failure detection  

International Nuclear Information System (INIS)

Purpose: To reliably detect fuel failures and estimate the failure scale by removing the effects of interferring nuclides. Constitution: Since the fuel failure has been detected by the method based on the monitoring for the radiation level of rare gases in the exhaust gas system, the detection undergoes the effect of gaseous interferring nuclides such as Ni-16 formed upon activation of reactor water, and fluctuation in the rare gases may possibly be overlooked if there should occur fuel failure. According to this invention, radioactive dusts such as Cs-138 or Rb-88 formed upon decay of rare gas nuclides are noted and these radioactive dusts are collected and measured. That is, a portion of gases in the exhaust gas system is collected by a sampling device, radioactive dusts contained therein are collected and the radiation dose thereof is detected. The detection signal is inputted into a signal processing device and the presence of a fuel failure and the scale of the fuel failure are judged due to the fluctuating tendency. (Kamimura, M.)

135

Radiation measuring device for use in fuel failure detection  

Energy Technology Data Exchange (ETDEWEB)

Purpose: To reliably detect fuel failures and estimate the failure scale by removing the effects of interferring nuclides. Constitution: Since the fuel failure has been detected by the method based on the monitoring for the radiation level of rare gases in the exhaust gas system, the detection undergoes the effect of gaseous interferring nuclides such as Ni-16 formed upon activation of reactor water, and fluctuation in the rare gases may possibly be overlooked if there should occur fuel failure. According to this invention, radioactive dusts such as Cs-138 or Rb-88 formed upon decay of rare gas nuclides are noted and these radioactive dusts are collected and measured. That is, a portion of gases in the exhaust gas system is collected by a sampling device, radioactive dusts contained therein are collected and the radiation dose thereof is detected. The detection signal is inputted into a signal processing device and the presence of a fuel failure and the scale of the fuel failure are judged due to the fluctuating tendency. (Kamimura, M.).

Ito, Toshiaki; Yamaga, Satoru

1987-11-02

136

Radiation detection with superconducting granular thin films  

International Nuclear Information System (INIS)

Superconducting granular thin films are considered to be an array of Josephson junctions and can be used as fast, sensitive detectors of microwave and submillimeter wave radiation. This paper describes the experimental results on detection of 10 GHz and HCN laser radiation with tin granular thin films. In order to investigate the relationship between the granular structure and the sensitivity, several kinds of tin granular thin films are made with changing background pressure and substrate temperature which is controlled by a Peltier refrigerator. Optical microscope photographs show that the evaporation at lower background pressure from 10-7 to 10-8 mm Hg makes the tin granules more separate (they are connected to one another by narrow bridges) and that the evaporation with lower substrate temperature makes tin granules smaller. The films having high responsivity are obtained under the condition that the background pressure is 10-4--10-5 mm Hg and the substrate temperature is lowered about 10 K from room temperature. The responsivity values obtained are 9 x 106 V/W at 10 GHz and 270 V/W at 891 GHz

137

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

138

Detection methods for irradiated mites and insects  

International Nuclear Information System (INIS)

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

139

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

International Nuclear Information System (INIS)

s 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)

140

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

 
 
 
 
141

Detection of food irradiation with luminescence methods  

International Nuclear Information System (INIS)

Food irradiation is applied as method for the preservation of foods, the prevention of food spoilage and the inhibition of food-borne pathogens. Doses exceeding 10 kGy (10 kJ/kg) are not recommended by the WHO. The different legislation requires methods for the detection and the closimetry of irradiated foods. Among the physical methods based on the radiation-induced changes in inorganic, nonhygroscopic crystalline solids are thermoluminescence (TL), photostimulated luminescence (PSL) and lyoluminescence (LL) measurement. The luminescence methods were tested on natural minerals. Pure quartz, feldspars, calcite, aragonite and dolomite of known origin were irradiated, read out and analyzed to determine the influence of luminescence-activators and deactivators. Carbonate minerals show an orange-red TL easily detectable by blue-sensitive photomultiplier tubes. TIL-inactive carbonate samples may be identified by a lyoluminescence method using the reaction of trapped irradiation-generated charge carriers with the solvent during crystal-lattice breakup. The fine-ground mineral is dissolved in an alkaline complexing agent/chemiluminescence sensitizer/chemiluminescence catalyst (EDTA/luminol/hemin) reagent mixture. The TL and PSL of quartz is too weak to contribute a significant part for the corresponding signals in polymineral dust. Alkali and soda feldspar show intense TL and PSL. The temperature maxima in the TL glow curves allow a clear distinction. PSL does not give this clear distinction. PSL does not give this additional information, it suffers from bleaching by ambient light and requires light-protection. Grain disinfestated with low irradiation doses (500 Gy) may not identified by both TL and PSL measurement. The natural TL of feldspar particles may be overlap with the irradiation-induced TL of other minerals. As a routine method, irradiated spices are identified with TL measurement. The dust particles have to be enriched by heavy-liquid flotation and centrifugation. The PSL method allows a clear identification of irradiated spices. The detection of irradiated seafood (mollusks and crustaceans) with TL is only possible for calcitic shells. The EDTA-luminol lyoluminescence is applicable for both calcitic and aragonitic shells, calcitic, amorphous and partially hydroxyapatitic crustacean molts, and poultry bones. The application of chemical methods is much more susceptible to errors.The high-performance liquid chromatography-determination of ortho- and metatyrosine in low-fat poultry and shrimp meat did not allow any positive identification of irradiated samples. (author)

142

Method of detecting fuel failures  

International Nuclear Information System (INIS)

Purpose: To exactly exactly estimate the scale of fuel pin failures thereby judge the possibility for the continuation of the reactor operation, without resulting troubles to the reactor operation. Constitution: A portion of sodium as the coolants is bypassed from the pipeway exit of a primary coolant system at the reactor core exit and sodium is flown to circulate into a tank disposed in the bypass line and having a free liquid surface with cover gases. Then, the cover gases are blown into the sodium in the tank and, after forcively driving the rare gas nuclear fission products released in sodium into the cover gases upon failure of a fuel pin and separating from sodium, gamma-rays released from the rare gas nuclear fission products are detected by a gamma-detector disposed outside on the tank. In this method, a continuous measurement can be made at a high sensitivity with no effect of intense gamma-rays of 24Na present in the sodium. (Sekiya, K.)

143

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

144

Multi-spectral schottky barrier infrared radiation detection array  

International Nuclear Information System (INIS)

A multi-spectral Schottky barrier infrared detector array in which individual pixels of radiation from a remote radiating object are detected by two or more Schottky barrier infrared radiation detectors each having a different spectral response so as to provide a ''color'' discrimination for the array

145

Radiation Detection by Employing Periodic Packets in Power-Line Communication System  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The interference with existing radio broadcasting services because of unintentional radiation is a serious problem in power-line communication (PLC) systems. A radiation detection method based on burst packets, which had been proposed by the authors and was called scan and sum (SAS) method, was a low cost method and used to solve the problem. But its measurement took a long time and the burst packets occupied a channel. To shorten the measurement time, a new method based on period...

Areni, Intan Sari

2014-01-01

146

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

147

Analytical detection methods for irradiated foodstuff  

International Nuclear Information System (INIS)

Some analytical detection methods are used in the world. A detail of establishment of CEN Standards in 1996, one of them, is explained. Nine standards of CEN are adopted by the Codex Standards (General Codex Methods for detection of irradiated Food). Main analytical technologies and the standard method are stated. As the physical methods, ESR (Electron Spin Resonance), TL and PSL (Photostimulated Luminescence) method are described. On chemical methods, hydrocarbons method, 2-alkylcyclobutanone method and other methods are discussed. DNA method, DEFT/APC, LAL/GNB and DEFT/APC method are explained as the biological methods. The application methods of irradiated food and classification of analytical detection methods are shown. References after 1996 are reviewed. (S.Y.)

148

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

149

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

International Nuclear Information System (INIS)

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

150

Leak detection by vibrational diagnostic methods  

International Nuclear Information System (INIS)

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

151

A Proposed Hybrid Method For Islanding Detection  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper Islanding detection methods for distributed resources are reviewed. The mainly used islanding detection techniques may be classified as active and passive techniques. Passive techniques don’t perturb the system but they have larger nondetection zones, whereas active techniques have smaller nondetection zones but they perturbthe system. In this paper a new hybrid method is proposed for detecting islanding of inverter based distributed generators. This method is a combination of active frequency drift method and change in proportional power spectral density. Active frequency drift method is very effective in finding islanding with various modifications. Itsdrawbacks are overcome by change in proportional power spectral density method.

SMITA SHRIVASTAVA,

2010-05-01

152

Discrete ordinates methods for radiation transport  

International Nuclear Information System (INIS)

The discrete ordinates (SN) method, first developed for stellar atmospheres, has been used extensively on various other radiation transport problems. In reactor analysis the method is generally used to generate parameters for design models based on more approximate but less expensive methods (such as diffusion theory) so that the spatial-spectrum coupling is represented accurately on a microscopic reaction rate level. It has a decisive advantage over Monte Carlo methods in computing the pin and assembly power profiles. In shielding problems where the penetration of the radiation can be deep, the method is used widely in design calculations. In oil-well logging problems, which also involve deep penetration and have a stringent accuracy requirement on the detector responses, the method complements the Monte Carlo techniques. One early application of the SN method was on one-dimensional radiative transfer problems. The discrete ordinates method has also been used in charged-particle transport problems. While the method has been applied primarily to static problems, one-dimensional time-dependent codes have existed since the early 1970s. In this paper the authors briefly review the basic method, illustrate its applications, discuss its merits and pitfalls, and enumerate the recent advances in the attendant numerical techniques that have enhanced the capabilities of the method

153

Measuring methods for whole beta radiations  

International Nuclear Information System (INIS)

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

154

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

International Nuclear Information System (INIS)

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

155

Improved flaw-detection method  

Science.gov (United States)

Holographic detection of unbonded or delaminated surfaces of materials and structures is improved by using helium instead of air in vacuum test chamber. Helium has index of refraction closer to vacuum (unity) than air. Therefore changes in chamber pressure during test do not alter index of refraction as much as they do with air. With air, much of detail is lost, particularly in curved areas.

Platt, R. J., Jr.

1980-01-01

156

Device for detection of ionizing radiation dose  

International Nuclear Information System (INIS)

The design of a detector is described which consists of an airtight bushing filled with gas under mild underpressure. At one end of the detector there is a window through which passes ionizing radiation. The advantage of the detector claimed is the accuracy of measurement of the dose of a specific ionizing radiation, the simple design and the continuous use of the detector at certain time intervals. (E.S.). 1 fig

157

Detection of radiation pressure acting on 2009 BD  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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) ...

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

2011-01-01

158

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

159

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

160

Detecting small low emission radiating sources  

CERN Document Server

The article addresses the possibility of robust detection of geometrically small, low emission sources on a significantly stronger background. This problem is important for homeland security. A technique of detecting such sources using Compton type cameras is developed, which is shown on numerical examples to have high sensitivity and specificity and also allows to assign confidence probabilities of the detection. 2D case is considered in detail.

Allmaras, Moritz; Hristova, Yulia; Kanschat, Guido; Kuchment, Peter

2010-01-01

 
 
 
 
161

Method and apparatus for detecting and quantifying radioactive material on tubing in a borehole  

International Nuclear Information System (INIS)

This patent describes a method for detecting and quantifying radioactive material deposited on the wall of a tubing disposed in a borehole. It comprises detecting radiation emitted by the radioactive material by lowering through the tubing a logging tool provided with gamma ray detector means; and calculating from the radiation detected in the tubing, the radioactivity level which would be detected outside and in the vicinity of the tubing

162

A Fault Detection Method for Reversible Circuits  

Directory of Open Access Journals (Sweden)

Full Text Available This paper represents a redundancy based mechanism for fault detection in reversiblecircuits. In this method reversible circuit has been duplicated for fault detection. This duplication isbased on self complementary feature of reversible circuits. We have used a fully redundant circuitand a comparator for the purpose fault detection. In order to analyze the proposed method, singleand double faults have been investigated in the following four cases: fault tolerant comparator andsingle fault, non-fault tolerant comparator and single fault, fault tolerant comparator and doublefault, non-fault tolerant comparator and double fault. The results show that the proposed techniqueoffers 100%, 83%, 75% and 64% of fault detection respectively.

Maryam Barshan

2011-09-01

163

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

164

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

165

Method of detecting sulfur dioxide  

Science.gov (United States)

(CH.sub.3).sub.3 SiNSO is produced by the reaction of ((CH.sub.3).sub.3 Si).sub.2 NH with SO.sub.2. Also produced in the reaction are ((CH.sub.3).sub.3 Si).sub.2 O and a new solid compound [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ]. Both (CH.sub.3).sub.3 SiNSO and [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ] have fluorescent properties. The reaction of the subject invention is used in a method of measuring the concentration of SO.sub.2 pollutants in gases. By the method, a sample of gas is bubbled through a solution of ((CH.sub.3).sub.3 Si).sub.2 NH, whereby any SO.sub.2 present in the gas will react to produce the two fluorescent products. The measured fluorescence of these products can then be used to calculate the concentration of SO.sub.2 in the original gas sample. The solid product [NH.sub.4][(CH.sub.3).sub.3 SiOSO.sub.2 ] may be used as a standard in solid state NMR spectroscopy.

Spicer, Leonard D. (Salt Lake City, UT); Bennett, Dennis W. (Clemson, SC); Davis, Jon F. (Salt Lake City, UT)

1985-01-01

166

Methods and systems for remote detection of gases  

Science.gov (United States)

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

Johnson, Timothy J

2012-09-18

167

Remote infrared radiation detection using piezoresistive microcantilevers  

Energy Technology Data Exchange (ETDEWEB)

A novel micromechanical infrared (IR) radiation sensor has been developed using commercially available piezoresistive microcantilevers. Microcantilevers coated with a heat absorbing layer undergo bending due to the differential stress between the top layer (coating) and the substrate. The bending causes a change in the piezoresistance and is proportional to the amount of heat absorbed. The microcantilever IR sensor exhibits two distinct thermal responses: a fast one ({lt}ms) and a slower one ({approximately}10 ms). A noise equivalent power (at a modulation frequency of 30 Hz) was estimated to be {approximately}70 nW/Hz{sup 1/2}. This value can be further reduced by designing microcantilevers with better thermal isolation that can allow microcantilevers to be used as uncooled IR radiation detectors. {copyright} {ital 1996 American Institute of Physics.}

Datskos, P.G.; Oden, P.I.; Thundat, T.; Wachter, E.A.; Warmack, R.J.; Hunter, S.R. [Health Sciences Research Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

1996-11-01

168

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

International Nuclear Information System (INIS)

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

169

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

170

Method and apparatus for measuring spatial uniformity of radiation  

Science.gov (United States)

A method and apparatus for measuring the spatial uniformity of the intensity of a radiation beam from a radiation source based on a single sampling time and/or a single pulse of radiation. The measuring apparatus includes a plurality of radiation detectors positioned on planar mounting plate to form a radiation receiving area that has a shape and size approximating the size and shape of the cross section of the radiation beam. The detectors concurrently receive portions of the radiation beam and transmit electrical signals representative of the intensity of impinging radiation to a signal processor circuit connected to each of the detectors and adapted to concurrently receive the electrical signals from the detectors and process with a central processing unit (CPU) the signals to determine intensities of the radiation impinging at each detector location. The CPU displays the determined intensities and relative intensity values corresponding to each detector location to an operator of the measuring apparatus on an included data display device. Concurrent sampling of each detector is achieved by connecting to each detector a sample and hold circuit that is configured to track the signal and store it upon receipt of a "capture" signal. A switching device then selectively retrieves the signals and transmits the signals to the CPU through a single analog to digital (A/D) converter. The "capture" signal. is then removed from the sample-and-hold circuits. Alternatively, concurrent sampling is achieved by providing an A/D converter for each detector, each of which transmits a corresponding digital signal to the CPU. The sampling or reading of the detector signals can be controlled by the CPU or level-detection and timing circuit.

Field, Halden (Boulder, CO)

2002-01-01

171

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

172

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)

173

System and method for assaying radiation  

Science.gov (United States)

A system for assaying radiation includes a sample holder configured to hold a liquid scintillation solution. A photomultiplier receives light from the liquid scintillation solution and generates a signal reflective of the light. A control circuit biases the photomultiplier and receives the signal from the photomultiplier reflective of the light. A light impermeable casing surrounds the sample holder, photomultiplier, and control circuit. A method for assaying radiation includes placing a sample in a liquid scintillation solution, placing the liquid scintillation solution in a sample holder, and placing the sample holder inside a light impermeable casing. The method further includes positioning a photomultiplier inside the light impermeable casing and supplying power to a control circuit inside the light impermeable casing.

DiPrete, David P; Whiteside, Tad; Pak, Donald J; DiPrete, Cecilia C

2013-11-12

174

Apparatuses and methods for detecting, identifying and quantitating radioactive nuclei and methods of distinguishing neutron stimulation of a radiation particle detector from gamma-ray stimulation of a detector  

Science.gov (United States)

In one aspect, the invention encompasses a method of detecting radioactive decay, comprising: a) providing a sample comprising a radioactive material, the radioactive material generating decay particles; b)providing a plurality of detectors proximate the sample, the detectors comprising a first set and a second set, the first set of the detectors comprising liquid state detectors utilizing liquid scintillation material coupled with photo tubes to generate a first electrical signal in response to decay particles stimulating the liquid scintillation material, the second set of the detectors comprising solid state detectors utilizing a crystalline solid to generate a second electrical signal in response to decay particles stimulating the crystalline solid; c) stimulating at least one of the detectors to generate at least one of the first and second electrical signals, the at least one of the first and second electrical signals being indicative of radioactive decay in the sample. In another aspect, the invention encompasses an apparatus for identifying and quantitating radioactive nuclei of a sample comprising radioactive material that decays to generate neutrons and high-energy .gamma.-rays.

Cole, Jerald D. (Idaho Falls, ID); Drigert, Mark W. (Idaho Falls, ID); Reber, Edward L. (Idaho Falls, ID); Aryaeinejad, Rahmat (Idaho Falls, ID)

2001-01-01

175

Detecting solar chameleons through radiation pressure  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

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

2014-01-01

176

Theoretical studies of densiometric methods using ?-radiation  

International Nuclear Information System (INIS)

Some conclusions could be drawn from the calculations performed for the practical measuring method to be applied: 1) The incident method for the density measurement of an inhomogenous two-phase flow involves a lot of errors. 2) Should one, due to limited expense, only use two detectors for the measuring chains, then the scattered-beam method is more advantageous than the two-beam method. 3) If three detectors can be used, a greater accuracy can be expected than with the scattered-beam method. 4) The accuracy of all methods increases if a certain homogenity of a part of the flow is allowed. 5) The most favourable energy region is different for scattered-beam and multi-beam processes. Whereas the scattered-beam method can be used to an optimum at energies of about 60 KeV due to the enlarged scattering cross sections at small radiation energies, the energies with multi-beam methods should be more than 100 KeV. 6) If small calibration problems are important, than the multi-beam method is preferable to the scattered-beam method. A good compromise between apparative expenditure and the accuracy to be obtained is the three-beam method with, e.g., 137Cs as a source. (orig./LH)

177

A method of detecting coherent synchrotron modes  

International Nuclear Information System (INIS)

A method for measuring coherent longitudinal synchrotron modes is developed and tested at the Indiana University Cyclotron Facility Cooler Ring. This method can be used to detect the onset of coherent instability and can provide important diagnosis for the control of beam brightness. Some possible improvement of this technique is discussed. (orig.)

178

Development of radiation detection and measurement systems  

Energy Technology Data Exchange (ETDEWEB)

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.

Moon, B. S.; Ham, C. S.; Chung, C. E. and others

2000-03-01

179

Nuclear radiation detection properties of diamond  

International Nuclear Information System (INIS)

The thermoluminescence behaviour of natural diamond and conventional synthetic diamond after irradiation by ionizing radiations was studied. In line with the findings of other researchers, the shortcomings of these stones, when used as thermoluminescence dosimeters, are highlighted. In particular the relatively low sensitivity in common synthetic diamond is attributed to the presence of nitrogen. Systematic decreasing of the nitrogen level indicates unambigously that the thermoluminescence sensitivity increases substantially. Experimental evidence strongly suggests that the nitrogen, which is generally accepted to appear in synthetic diamond in dispersed paramagnetic form, acts as non-radiative recombination centres for charge carriers. Further improvement in the thermoluminescence response occurs with the incorporation of boron. A triple role model for the impurity boron in synthetic diamond is evidenced by an increase in the linearity of the thermoluminescence response, an increase in the thermoluminescence intensity, and the appearance of shallow trapping levels which give rise to thermoluminescence glow peaks below room temperature. Practical dosimeters should be relatively insensitive to ambient lighting. The effect of incorporated nickel in suppressing this sensitivity is highlighted. There is a suggested correlation between the presence of the W8 ESR-line (which has been associated with the presence of nickel) and the degree to which the synthetic diamond is sensitive to ambient lighting. Experimental data in support of the concept that the luminescence centre is due to associated donor-acceptor pairs with the boron being the acceptor are presented. No support however, for the A-aggregate per se being the major donor responsible for emission in the visible region could be found. 106 figs., 26 tabs., 180 refs

180

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.)

 
 
 
 
181

Eye blinking-based method for detecting driver drowsiness.  

Science.gov (United States)

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

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

2014-11-01

182

Method research of detecting high-energy neutron in pulse fission neutron energy spectrum  

International Nuclear Information System (INIS)

Technical methods of increasing high-energy neutron sensitivity of detecting system and signal-to noise of measurement are discussed. Through optimization of detecting system structure, neutron sensitivity of detecting system is increased. Influence of background radiation, such as scattered neutron and scattered gamma, are calculated. Results indicate, fission high-energy neutron can be measured with low intensities and high-intensity radiation background. (authors)

183

Nanophosphors and outlooks for their use in ionizing radiation detection  

International Nuclear Information System (INIS)

The fundamental properties of nanophosphors determined by their structural state are discussed. The influence of a high concentration of surface trapping centers and quantum confinement effect on the nanophosphor luminescence characteristics is noted. These features determine some new properties, which are important for radiation detection. They include the increase in the luminescence yield under high-dose irradiation and improvement of radiation resistance. The luminescence and dosimetric properties of nanophosphors of different compositions are described. It is noted that nanophosphors show promise as high-dose detectors of ionizing radiation.

184

Apparatus for detecting ionizing radiation while correcting distortion  

International Nuclear Information System (INIS)

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

185

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

CERN Document Server

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

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

2011-01-01

186

Method and system for laughter detection  

Science.gov (United States)

A method and apparatus for laughter detection. Laughter is detected through the presence of a sequence of at least a predetermined number such as three consecutive bursts, each burst comprising a voiced portion and an unvoiced portion. After detecting bursts, n-tuples such as triplets are detected, and a likelihood of each burst N-tuple to represent laughter is provided by comparison to predetermined thresholds. Finally, a total score is assigned to the signal based on the grades associated with the triplets and parameters such as the distance between the N-tuples, the total score representing the probability that the audio signal comprises a laughter episode. The method and apparatus preferably comprise a training step and module for determining the thresholds according to manually marked audio signals.

2013-10-29

187

A simple method of detecting staphylococcal hemolysins.  

Science.gov (United States)

A modification of the "one-plate method" for detection of staphylococcal hemolysins has been described. Bacterial strains of Staphylococcus aureus, Streptococcus agalactiae and Cornebacterium pseudotuberculosis were replaced by their prepurified hemolytically active exosubstances: beta-toxin, CAMP-factor, and, the exosubstance of Corynebacterium pseudotuberculosis called COREX. By means of the modification described, exact detection of hemolysins in possible with staphylococcal strains producing one type of hemolysin as well as with strains producing a combination of hemolysins. PMID:44782

Skalka, B; Smola, J; Pillich, J

1979-01-01

188

Detectable Signatures of Cosmic Radiative Feedback  

CERN Document Server

We use a semi-analytical model to study the impact of reionization, and the associated radiative feedback, on galaxy formation. Two feedback models have been considered: (i) a standard prescription, according to which star formation is totally suppressed in galaxies with circular velocity below a critical threshold (model CF06) and (ii) a characterization based on the filtering scale (model G00), allowing for a gradual reduction of the gas available for star formation in low-mass galaxies. In model CF06 reionization starts at z ~ 15-20, is 85% complete by z ~ 10; at the same z, the ionized fraction is 16% in model G00. The models match SDSS constraints on the evolution of the neutral hydrogen fraction at z < 7, but predict different Thomson optical depths, tau_e = 0.1017 (CF06), and 0.0631 (G00); such values are within 1 sigma of the WMAP 3-yr determination. Both models are in remarkable good agreement with additional existing data (evolution of Lyman-limit systems, cosmic star formation history, high-z ga...

Schneider, R; Choudhury, T Roy; Ferrara, A; Burigana, C; Popa, L A

2007-01-01

189

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

190

New Sequential Methods for Detecting Portscanners  

CERN Document Server

In this paper, we propose new sequential methods for detecting port-scan attackers which routinely perform random "portscans" of IP addresses to find vulnerable servers to compromise. In addition to rigorously control the probability of falsely implicating benign remote hosts as malicious, our method performs significantly faster than other current solutions. Moreover, our method guarantees that the maximum amount of observational time is bounded. In contrast to the previous most effective method, Threshold Random Walk Algorithm, which is explicit and analytical in nature, our proposed algorithm involve parameters to be determined by numerical methods. We have developed computational techniques such as iterative minimax optimization for quick determination of the parameters of the new detection algorithm. A framework of multi-valued decision for testing portscanners is also proposed.

Chen, Xinjia

2012-01-01

191

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)

192

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

193

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)

194

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

195

A Bayesian method for detecting stellar flares  

CERN Document Server

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

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

2014-01-01

196

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

197

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

198

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.

Hansen, Trine; Löfström, Charlotta

2013-01-01

199

Methods of leak detection in chemical plants  

International Nuclear Information System (INIS)

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

200

Flow cytometric detection method for DNA samples  

Science.gov (United States)

Disclosed herein are two methods for rapid multiplex analysis to determine the presence and identity of target DNA sequences within a DNA sample. Both methods use reporting DNA sequences, e.g., modified conventional Taqman.RTM. probes, to combine multiplex PCR amplification with microsphere-based hybridization using flow cytometry means of detection. Real-time PCR detection can also be incorporated. The first method uses a cyanine dye, such as, Cy3.TM., as the reporter linked to the 5' end of a reporting DNA sequence. The second method positions a reporter dye, e.g., FAM.TM. on the 3' end of the reporting DNA sequence and a quencher dye, e.g., TAMRA.TM., on the 5' end.

Nasarabadi,Shanavaz (Livermore, CA); Langlois, Richard G. (Livermore, CA); Venkateswaran, Kodumudi S. (Round Rock, TX)

2011-07-05

 
 
 
 
201

Detection of radiation from a Ti:sapphire laser with a high space - time resolution  

International Nuclear Information System (INIS)

A high space - time resolution is achieved in detection of radiation from a Ti:sapphire laser by the methods of femtosecond photoelectronics. A time resolution of 2 x 10-13 s is obtained at wavelength of 800 nm in a linear scan regime for a streak speed of 5 x 1010 cm s-1, an input power density of (1 - 5) x 103 W cm-2, and a linear dynamic detection range no more than 10. (letters)

202

Method for the detection of aquaretic compounds  

DEFF Research Database (Denmark)

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

Hadrup, Niels Technical University of Denmark,

203

Detection of radiation treatment of frozen chicken using a quick microgel electrophoresis assay  

International Nuclear Information System (INIS)

DNA Comet Assay (microgel electrophoresis of single cell) is very useful and sensitive analytical technique to investigate several types of damages of DNA - especially the fragmentation. As DNA is the essential part of several foods, either animal or plant origin, therefore this method is versatile and valuable for detection of radiation treatment of several types of food. Ionizing radiation causes DNA breakage, fragmentation, base modification and single- or double-strand breaks. Therefore, the detection of fragmented DNA present in any kind or type of food can serve as the marker of detection of radiation treatment. The cells from the chicken samples (unirradiated and irradiated) were extracted in cold PBS, embedded in agarose on microscope slides, lysed for 15 minutes in 2.5 % SDS and electrophoressed at a rate of 2V /cm for 2 minutes. After silver staining, the slides were evaluated through an ordinary transmission microscope. In irradiated samples, fragmented DNA (due to radiation treatment) stretched towards the anode and cells appearing as comets. The density of DNA in the tails increased with increasing radiation dose. However, in non-irradiated samples, the large molecule of DNA remained relatively intact and there was only minor or no migration of DNA; the cells were round or had very short tails. Therefore, DNA comet assay provides an inexpensive, rapid and relatively simple screening method for several kinds of radiation-processed and untreated foods. (autiation-processed and untreated foods. (author)

204

ANOLE Portable Radiation Detection System Field Test and Evaluation Campaign  

Energy Technology Data Exchange (ETDEWEB)

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

Chris A. Hodge

2007-07-12

205

ANOLE Portable Radiation Detection System Field Test and Evaluation Campaign  

International Nuclear Information System (INIS)

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

206

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

207

Method and apparatus for detecting an analyte  

Science.gov (United States)

We describe the use of coordination polymers (CP) as coatings on microcantilevers for the detection of chemical analytes. CP exhibit changes in unit cell parameters upon adsorption of analytes, which will induce a stress in a static microcantilever upon which a CP layer is deposited. We also describe fabrication methods for depositing CP layers on surfaces.

Allendorf, Mark D. (Pleasanton, CA); Hesketh, Peter J. (Atlanta, GA)

2011-11-29

208

Method for detecting sophisticated cyber attacks  

Science.gov (United States)

A method of analyzing computer intrusion detection information that looks beyond known attacks and abnormal access patterns to the critical information that an intruder may want to access. Unique target identifiers and type of work performed by the networked targets is added to audit log records. Analysis using vector space modeling, dissimilarity matrix comparison, and clustering of the event records is then performed.

Potok, Thomas E. (Oak Ridge, TN)

2008-11-18

209

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

210

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)

211

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

212

Motion Detection Using Adaptive Temporal Averaging Method  

Directory of Open Access Journals (Sweden)

Full Text Available Motion detection methods are widely integrated in modern intelligent video surveillance systems. Many of these methods use background subtraction techniques to separate the foreground objects from the background. Temporal averaging is one of the most commonly used and simple method for background subtraction. In this paper we propose new version of the original Temporal averaging algorithm. The speed of updating the background model has been modified to be adaptive and determined by pixel difference. Another approach with simultaneously adaptive threshold and background update speed is also proposed. Our goal is increasing the F-measure of the method by making the algorithm more versatile for different scene scenarios. Experimental results are shown and analyzed. The quality parameters of the original method and the proposed method are compared.

B. Nikolov

2014-06-01

213

Passive radiation detection using optically active CMOS sensors  

Science.gov (United States)

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

Dosiek, Luke; Schalk, Patrick D.

2013-05-01

214

Proceedings of the symposium on Nuclear Radiation Detection Materials  

International Nuclear Information System (INIS)

address 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

215

Delay-Line Three-Dimensional Position Sensitive Radiation Detection  

Science.gov (United States)

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

Jeong, Manhee

216

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

217

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

218

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

219

A space radiation transport method development  

Science.gov (United States)

Improved spacecraft shield design requires early entry of radiation constraints into the design process to maximize performance and minimize costs. As a result, we have been investigating high-speed computational procedures to allow shield analysis from the preliminary design concepts to the final design. In particular, we will discuss the progress towards a full three-dimensional and computationally efficient deterministic code for which the current HZETRN evaluates the lowest-order asymptotic term. HZETRN is the first deterministic solution to the Boltzmann equation allowing field mapping within the International Space Station (ISS) in tens of minutes using standard finite element method (FEM) geometry common to engineering design practice enabling development of integrated multidisciplinary design optimization methods. A single ray trace in ISS FEM geometry requires 14 ms and severely limits application of Monte Carlo methods to such engineering models. A potential means of improving the Monte Carlo efficiency in coupling to spacecraft geometry is given in terms of re-configurable computing and could be utilized in the final design as verification of the deterministic method optimized design. Published by Elsevier Ltd on behalf of COSPAR.

Wilson, J. W.; Tripathi, R. K.; Qualls, G. D.; Cucinotta, F. A.; Prael, R. E.; Norbury, J. W.; Heinbockel, J. H.; Tweed, J.

2004-01-01

220

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.

 
 
 
 
221

Development of detection methods for irradiated foods  

International Nuclear Information System (INIS)

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

222

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

223

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

224

Development of landmine detection system by measuring radiations from landmine  

International Nuclear Information System (INIS)

Since mines left underground are small and covered with plastics, not with metal, ordinary metal detection system is difficult to detect, new landmine detection system by irradiating neutrons using a portable D-D nuclear fusion neutron source and measuring radiations from landmine has been developed. Neutron reaction with an explosive emits capture gamma ray having specific energy. The atomicity density ratio in an explosive can identify a kind as well as presence of a mine by measuring capture gamma ray of different energy produced by hydrogen and nitrogen at the same time. In addition, a position of a mine can be identified with measuring a backscattering neutron with plural detectors at the same time. Using melamine powder instead of explosive, the detection system using a BGO scintillator surrounded by a NAI scintillator was demonstrated in the experiment. Its field test is planned in March 2007. (T. Tanaka)

225

Apparatus and method for radiation processing of materials  

International Nuclear Information System (INIS)

A method and apparatus for radiation degradation processing of polytetrafluoroethylene makes use of a simultaneous irradiation, agitation and cooling. The apparatus is designed to make efficent use of radiation in the processing. (author)

226

Machine Learning Methods for Visual Object Detection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The goal of this thesis is to develop better practical methods for detecting common object classes in real world images. We present a family of object detectors that combine Histogram of Oriented Gradient (HOG), Local Binary Pattern (LBP) and Local Ternary Pattern (LTP) features with efficient Latent SVM classifiers and effective dimensionality reduction and sparsification schemes to give state-of-the-art performance on several important datasets including PASCAL VOC2006 and VOC2007, INRIA Pe...

Hussain, Sibt Ul

2011-01-01

227

Radiation pressure detection and density estimate for 2011 MD  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present our astrometric observations of the small near-Earth object 2011~MD ($H \\sim 28.0$), obtained after its very close fly-by to Earth in June 2011. 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 $5\\sigma$. The detection can be used to put constraints on the density of the obj...

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

2014-01-01

228

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)

229

Small Teleoperated Robot for Nuclear Radiation and Chemical Leak Detection  

Directory of Open Access Journals (Sweden)

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

Kui Qian

2012-09-01

230

Detection of radiation, electronic signal processing, counting statistics  

International Nuclear Information System (INIS)

Full text: This paper will concern itself with the detection of radiation resulting from scattering in x ray diffractometers. In the first instance a description will be given of photon counting detectors which are commonly found in laboratory XRD systems. This will be extended to a discussion of one- and two-dimensional detection systems such as charge coupled semiconductor detector arrays, Si Li and intrinsic germanium solid state detectors and imaging plates. A description of the types of monochromators commonly used in laboratory and synchrotron radiation systems will be given. Criteria for establishing the optimum coupling of the diffracted beams from the experiment to the detector system will be given. As well, the paper will describe techniques for analyzing the data from diffraction experiments for conventional and energy dispersive detector systems. Copyright (1999) Australian X-ray Analytical Association Inc

231

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

232

Designing metal-organic frameworks for radiation detection  

Energy Technology Data Exchange (ETDEWEB)

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.

Feng, Patrick L. [Sandia National Laboratories, California, 7011 East Ave, Livermore, CA 94550 (United States); Branson, Janelle V.; Hattar, Khalid; Vizkelethy, Gyorgy [Sandia National Laboratories, New Mexico, PO Box 5800, Albuquerque, NM 87185 (United States); Allendorf, Mark D. [Sandia National Laboratories, California, 7011 East Ave, Livermore, CA 94550 (United States); Patrick Doty, F., E-mail: fpdoty@sandia.gov [Sandia National Laboratories, California, 7011 East Ave, Livermore, CA 94550 (United States)

2011-10-01

233

Application of single-chip microcomputer in radiation detection  

International Nuclear Information System (INIS)

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

234

Noise Radiation Measure-Sound Power and its Test Methods  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Zeng Xianren; Zuo Yanyan

2013-01-01

235

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

236

A Photon Free Method to Solve Radiation Transport Equations  

International Nuclear Information System (INIS)

The multi-group discrete-ordinate equations of radiation transfer is solved for the first time by Newton's method. It is a photon free method because the photon variables are eliminated from the radiation equations to yield a NgroupXNdirection smaller but equivalent system of equations. The smaller set of equations can be solved more efficiently than the original set of equations. Newton's method is more stable than the Semi-implicit Linear method currently used by conventional radiation codes

237

Numerical methods in multidimensional radiative transfer  

CERN Document Server

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

Meinköhn, Erik

2008-01-01

238

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

239

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.)

240

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

 
 
 
 
241

A method for characterizing photon radiation fields  

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-04-01

242

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

243

New methods of performing radiation protection inspections in Norway  

International Nuclear Information System (INIS)

In recent years the Norwegian Radiation Protection Authority (NRPA) has put a lot of effort in working out new national radiation protection legislation. Less time-consuming administration of radiation users and radiation sources was one of the goals of the new legislation, hopefully giving more time for inspections. In the same period NRPA has tested out new methods of performing radiation protection inspections, going beyond the traditionally technical inspections. These methods, and also promising methods used by other regulatory bodies in the Health, Security and Environment (HSE) area in Norway, are described in this paper

244

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)

245

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)

246

Method of detecting fuel rod failure  

Energy Technology Data Exchange (ETDEWEB)

Purpose: To detect the failure of fuel rods in non-destructive manner by operating a nuclear magnetic resonance device. Method: The upper end of a fuel rod selected from a spent fuel assembly is exposed, around which a nuclear magnetic resonance device is disposed to detect the presence or absence of nuclear fission gases in the fuel rod to conduct failure detection of the fuel rod. The nuclear magnetic resonance device comprises a main magnet for applying static magnetic fields, Helmholtz coils and receiving coils disposed therein. In operation, main magnetic coils are connected to a power source, while the Helmholtz coils are connected to an oscillator respectively. Signals, when the fuel rod is disposed to the inside of the receiving coils are sent by way of an amplifier and a phase detector and applied with calculation processing in an electronic computer. In this way, presence or absence of nuclear fission gases in the fuel rod is detected and the amount of the nuclear fission gases can be calculated in the electronic computer. (Kamimura, M.).

Kumafuji, Hisao.

1988-05-06

247

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, 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.

248

Cave detection with GPR and seismic methods  

Science.gov (United States)

In the last few years building sites extended extraordinarily on the hilly part of Budapest, where protected caves can be found. New buildings are being built on the unbuilt areas, and existing houses are being enlarged. If we close the swallers we stop the growth of voids and stalagmites. It’s important to know the size, position and depth of natural voids and cavities before building or reconstruction. We used Ground Penetrating Radar (GPR) and shallow seismic measurements to detect these objects. The presentation shows the physical bases and some typical radar and shallow seismic sections. It illustrates the use of these methods with 4 case histories: 1 GPR measurement above a known cave system on Budapest, 2 3D measurement above an unknown cave in a limestone mine, 3 Searching the continuity of a known cave from the surface, 4 Detecting the continuity of a karstic system, which has underground lakes.

Neducza, B.; Hermann, L.; Pattantyus-Abraham, M.

2003-04-01

249

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

International Nuclear Information System (INIS)

luding 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

250

A dual-sided coded-aperture radiation detection system  

Energy Technology Data Exchange (ETDEWEB)

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 5x5x50 cm{sup 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., E-mail: robert.d.penny@saic.com [Science Applications International Corporation, 10740 Thornmint Rd., San Diego, CA 92124 (United States); Hood, W.E.; Polichar, R.M.; Cardone, F.H.; Chavez, L.G.; Grubbs, S.G.; Huntley, B.P.; Kuharski, R.A.; Shyffer, R.T. [Science Applications International Corporation, 10740 Thornmint Rd., San Diego, CA 92124 (United States); Fabris, L.; Ziock, K.P. [Oak Ridge National Laboratory, Oak Ridge, TN 37830 (United States); Labov, S.E.; Nelson, K. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States)

2011-10-01

251

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

252

A dual-sided coded-aperture radiation detection system  

International Nuclear Information System (INIS)

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 5x5x50 cm3 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.

253

Cellular telephone-based radiation sensor and wide-area detection network  

Energy Technology Data Exchange (ETDEWEB)

A network of radiation detection instruments, each having a small solid state radiation sensor module integrated into a cellular phone for providing radiation detection data and analysis directly to a user. The sensor module includes a solid-state crystal bonded to an ASIC readout providing a low cost, low power, light weight compact instrument to detect and measure radiation energies in the local ambient radiation field. In particular, the photon energy, time of event, and location of the detection instrument at the time of detection is recorded for real time transmission to a central data collection/analysis system. The collected data from the entire network of radiation detection instruments are combined by intelligent correlation/analysis algorithms which map the background radiation and detect, identify and track radiation anomalies in the region.

Craig, William W. (Pittsburg, CA); Labov, Simon E. (Berkeley, CA)

2006-12-12

254

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1985-07-01

255

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

256

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

257

Apparatus and method for detecting explosives  

International Nuclear Information System (INIS)

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

258

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)

259

Detecting method and device for pipeline  

International Nuclear Information System (INIS)

The present invention provides a method of and a device for diagnosing integrity of pipelines having the surfaces being in a corrosive atmosphere in a nuclear power plant. Namely, through holes are perforated to the pipeline. The predetermined area in the inside of the pipeline is scanned by laser light through the through holes. A luminance distribution of the laser light reflected at the inner circumference of the pipeline is photographed by a CCD camera. The images of the distribution of the luminance is processed to pick out a failed state. The image of the failed state is measured to determine the dimension of the failure. Alternatively, an inspection module having a function of irradiating laser light and detecting the lasers is inserted from a portion which can be removed upon conducting detection among the inside of the pipeline system to a position of the object to be detected. A predetermined area is scanned by laser light. The luminance distribution of the laser light reflected in the pipeline is photographed by the CCD camera. The images of the luminance distribution are processed to pick out the failed state, and the image of the failed state is measured to determine the dimension of the failure. (I.S.)

260

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

 
 
 
 
261

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 information available from a plastic detector to discriminate other man-made radiation source from NORM

262

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.)

263

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

264

Sodium boiling detection by acoustic method  

International Nuclear Information System (INIS)

Sodium boiling experiments were conducted using the out-of-pile sodium loop with 91 mimic fuel pins subassembly in order to establish the acoustic detection method of sodium boiling in an FBR reactor core. The following results were obtained concerning the characteristic of sodium boiling sound, the method of signal processing and the void effect. (1) Acoustic pressure by sodium boiling increases according to the boiling level, and the maximum acoustic pressure reaches about 1,000 Pa. (2) Boiling appears with a constant period; the period becomes longer with the increase of saturation temperature, to about 0.7s at last. (3) Acoustic spectrum detected by an in-sodium sensor has mainly lower frequency components; and by an on-wrapper tube sensor, mainly higher frequency components. (4) Smoothing processing of acoustic signals is necessary for the cross-correlation treatment in order to obtain the time lag between the signals of two sensors. Also, informations on the acoustic pressure due to fission gas release and its diminishing effect on boiling acoustics were obtained through the mimic test with Ar gas injection. (author)

265

New method to detect caries via fluorescence  

Science.gov (United States)

Caries, a common and widespread infectious disease, has to be detected as early as possible. Based on the need for an easy and handy tool for preventing invasive treatment a new fluorescence camera system has been developed. Using this camera the so-called porphyrins, metabolic products of oral pathogenic bacteria can be visualized. Thereby fluorophores are excited at a wavelength of 405nm by the built-in GaN-LEDs. Healthy and diseased dental hard tissues fluoresce in the green and in the red spectral range, respectively, thus allowing differentiation by coulor. To prove the reliability of this fluorescence camera system, freshly extracted teeth were examined. Three different methods of analysis were verified and compared to give information about the lesions (sensitivity & selectivity): The extent of the fluorescence area, the integral of the red/green ratio of the lesion and the maximum red/green ratio in the area of interest. Histological sections of the teeth served as reference. In addition, the camera was compared to a tip probe sensor already available on the market. In total, our results show that regarding the three different algorithms of analysis, the maximum of the red/green ratio is a preferential method to evaluate carious lesions. Sound tissue, enamel caries and dentin caries can be clearly distinguished. The new fluorescence camera is a handy, efficient and fast device in order to detect lesions and seems to be superior to the tip probe sensor regarding the positioning. Further studies are required.

Eberhart, J.; Frentzen, M.; Thoms, M.

2007-07-01

266

IR thermography methods in detection of buried mines  

Science.gov (United States)

Thermography is one of many techniques used for nondestructive testing for which both passive and active approach could be taken. The passive approach is effective for materials and structures which are naturally at a different temperature than the environment. The active approach requires an external heating source to stimulate the materials or structures to be tested. These methods can be also applied to detect mines hidden in the ground. Passive approach is used when natural heating of soil by sun radiation is exploited. In the case of active approach it is used an external heating source for example a microwave source to provide thermal stimulation. In this paper the results of our experiments with both methods carried out in the laboratory set-up and in the outdoor measuring field are presented.

Swiderski, Waldemar; Hlosta, Pawel; Miszczak, Maciej

2012-10-01

267

Development of DNA elution method to detect irradiated foodstuff  

International Nuclear Information System (INIS)

The aim of the work is to develop a reliable method to detect whether a fresh and frozen foodstuff has been irradiated. The molecule of DNA is one of the targets of ionizing radiation. The induction of three major classes of lesion have been shown. Double strand breaks, single strand breaks and base damage. Among the different techniques used to observe and quantify the strand breaks, techniques of elution are very interesting. The method proposed consisted of a filtration of the DNA at the atmospheric pressure and in non denaturing conditions. The amount of DNA retained on the filter is measured after being suitably labelled by microfluorometry. A difference in the amount of DNA retained on a filter of 2 ?m from a lysed muscular tissue sample between a frozen Norway lobster which has been irradiated and one which has not, is observed. 7 refs

268

Photocurrent-based detection of terahertz radiation in graphene  

International Nuclear Information System (INIS)

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

269

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

270

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

271

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

272

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

273

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

274

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

275

Radiation pressure detection and density estimate for 2011 MD  

CERN Document Server

We present our astrometric observations of the small near-Earth object 2011 MD ($H \\sim 28.0$), obtained after its very close fly-by to Earth in June 2011. 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 $5\\sigma$. The detection can be used to put constraints on the density of the object, pointing to either an unexpectedly low value of $\\rho = 510^{+250}_{-230} {\\mbox{ kg} / \\mbox{m} ^3}$ ($68\\%$ confidence interval) if we assume a typical probability distribution for the unknown albedo, or to an unusually high reflectivity of its surface. This may have important implications both in terms of impact hazard from small objects and in light of a possible ARRM to this target.

Micheli, Marco

2014-01-01

276

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)

277

Development of Angular Eigenvalue Method for Radiation Transport Problems  

International Nuclear Information System (INIS)

This paper describes the development of a new semianalytical method for radiation transport problems in slabs, i.e., the angular eigenvalue method (AEM), and its application to the penetration of gamma rays in slabs

278

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

279

Hazard Detection Methods for Lunar Landing  

Science.gov (United States)

The methods and experiences from the Apollo Program are fundamental building blocks for the development of lunar landing strategies for the Constellation Program. Each of the six lunar landing Apollo missions landed under near ideal lighting conditions. The astronauts visually performed terrain relative navigation while looking out of windows, and were greatly aided by external communication and well lit scenes. As the LM approached the landing site, the astronauts performed visual hazard detection and avoidance, also under near-ideal lighting conditions. The astronauts were looking out of the windows trying to the best of their ability to avoid rocks, slopes, and craters and find a safe landing location. NASA has expressed a desire for global lunar access for both crewed and robotic sortie lunar exploration missions (Cook, 2007) (Dale, 2006). Early NASA architecture studies have identified the lunar poles as desirable locations for early lunar missions. These polar missions have less than ideal lighting conditions and will significantly affect the way a crewed vehicle plans to land at such locales. Consequently, a variety of hazard identification methods should be considered for use by the crew to ensure a high degree of safety. This paper discusses such identification methods applicable to the poorly lit polar lunar environment, better ensuring global access for the soon to be designed Lunar Lander Vehicle (LLV).

Brady, Tye; Zimpfer, Doug; Robertson, Edward; Epp, Chirold; Paschall, Stephen

2009-01-01

280

Radiation impact arising from uses of neutrons for landmine detection  

International Nuclear Information System (INIS)

Description and discussion are given to the studies which were performed to assess the radiation impact in soil when neutrons are used to detect land mines by nuclear techniques. This was achieved by irradiating soil samples collected at different depths from land mine fields located at different regions in Egypt. The samples were exposed to the maximum neutron fluence which can be applied during land mine detection This was performed by irradiating the soil samples by neutrons emitted from Californium-252 source. The gamma spectra emitted from the irradiated samples were measured by gamma ray spectrometers with Nal(Tl) and HPGe detectors. The observed gamma lines and their intensities were used to identify the corresponding radio-nuclides and the activity concentration of each isotope. Estimation was also performed to assess the amount of 40K isotope which is produced in soil when irradiation.by neutrons during land mine detection. The obtained results of measured radioactive elements produced from neutron irradiation show clearly that, the radioactive elements,24Na, 38Cl, 56Mn, and 59Fe are produced at very low level. The data also show no indication of 40K. This means that using neutrons for land mine detection do not cause any sizable level of 40K compared with the naturally occurring one

 
 
 
 
281

Fast microwave detection system for coherent synchrotron radiation study at KEK: Accelerator test facility  

Science.gov (United States)

A fast room temperature microwave detection system based on the Schottky Barrier-diode detector was created at the KEK ATF (Accelerator Test Facility). It was tested using Coherent Synchrotron Radiation (CSR) generated by the 1.28 GeV electron beam in the damping ring. The speed performance of the detection system was checked by observing the CSR from a multi-bunch (2.8 ns bunch separation time) beam. The theoretical estimations of CSR power yield from an edge of bending magnet as well as new injection tuning method are presented. A very high sensitivity of CSR power yield to the longitudinal electron distribution in a bunch is discussed.

Aryshev, A.; Araki, S.; Karataev, P.; Naito, T.; Terunuma, N.; Urakawa, J.

2007-10-01

282

Solar cell anomaly detection method and apparatus  

Science.gov (United States)

A method is provided for detecting cracks and other imperfections in a solar cell, which includes scanning a narrow light beam back and forth across the cell in a raster pattern, while monitoring the electrical output of the cell to find locations where the electrical output varies significantly. The electrical output can be monitored on a television type screen containing a raster pattern with each point on the screen corresponding to a point on the solar cell surface, and with the brightness of each point on the screen corresponding to the electrical output from the cell which was produced when the light beam was at the corresponding point on the cell. The technique can be utilized to scan a large array of interconnected solar cells, to determine which ones are defective.

Miller, Emmett L. (Inventor); Shumka, Alex (Inventor); Gauthier, Michael K. (Inventor)

1981-01-01

283

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.)

284

Detection methods at reactor neutrino experiments  

Science.gov (United States)

In 2011 and 2012, the smallest neutrino mixing angle ?13 was determined to be unexpected large by reactor neutrino experiments Daya Bay, Double Chooz, and RENO, and accelerator experiments T2K and MINOS. The most precise measurement is sin22?13=0.089±0.010(stat.)±0.005(syst.), provided by Daya Bay. The measurement of ?13 opened the gateway to the mass hierarchy and CP phase measurements. It also marked the beginning of precision measurements in neutrino studies. With near-far relative measurement and improvements in detector design, the relative precision of neutrino detectors reached 0.2%. Detection methods for reactor neutrinos are reviewed. The highlighted techniques include gadolinium-doped liquid scintillator, three-layer detectors, functionally identical detectors, reflective panel, background shielding, etc. The next generation reactor neutrino experiment Daya Bay II and its technical challenges are briefly described.

Cao, Jun

2013-12-01

285

Detection methods at reactor neutrino experiments  

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-12-21

286

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

287

Conducting polymer/silicon heterojunction diode for gamma radiation detection  

Energy Technology Data Exchange (ETDEWEB)

In this work, alternative heterojunction devices to be used for gamma-radiation detection are presented. The high quality silicon/polyaniline heterostructures use polyaniline thin films as an active part of the device structure. Polyaniline thin films 40 nm thick were deposited onto silicon substrates (n-type, <100>, 1 O.cm) using the spin-coating technique from soluble polyaniline. The devices present excellent electrical characteristics, with a rectification ratio of 60,000 at {+-}1.0 V, reverse currents in the order of a few nA and ideality factor approximately 2. These electrical characteristics indicate great potential for their use in sensor application. The heterojunction diode is very sensitive to gamma radiation in the dose range of 0-7000 Gy, presenting a linear response in the forward and reverse bias. The excellent electrical characteristics, together with the linear response with the dose strongly suggest the application of this device for spectrometry or dosimetry of low and high doses of gamma ray radiation. (author)

Laranjeira, J.M.G.; Khoury, H.J.; Azevedo, W.M. de; Silva, E.F. da Jr.; Vasconcelos, A.E. de

2002-07-01

288

DETECCIÓN DE RADIACIÓN NO IONIZANTE / NON-IONIZING RADIATION DETECTION  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish 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

289

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)

290

Detecting a non-Gaussian stochastic background of gravitational radiation  

CERN Document Server

We derive a detection method for a stochastic background of gravitational waves produced by events where the ratio of the average time between events to the average duration of an event is large. Such a signal would sound something like popcorn popping. Our derivation is based on the somewhat unrealistic assumption that the duration of an event is smaller than the detector time resolution.

Drasco, S; Drasco, Steve; Flanagan, Eanna E.

2002-01-01

291

A Method for Ultrashort Electron Pulse Shape-Measurement Using Coherent Synchrotron Radiation  

CERN Document Server

In this paper we discuss a method for nondestructive measurements of the longitudinal profile of sub-picosecond electron bunches for X-Ray Free Electron Lasers (XFELs). The method is based on the detection of the Coherent Synchrotron Radiation (CSR) spectrum produced by a bunch passing a dipole magnet system. This work also contains a systematic treatment of synchrotron radiation theory which lies at the basis of CSR. Standard theory of synchrotron radiation uses several approximations whose applicability limits are often forgotten: here we present a systematic discussion about these assumptions. Properties of coherent synchrotron radiation from an electron moving along an arc of a circle are then derived and discussed. We describe also an effective and practical diagnostic technique based on the utilization of an electromagnetic undulator to record the energy of the coherent radiation pulse into the central cone. This measurement must be repeated many times with different undulator resonant frequencies in or...

Geloni, G A; Schneidmiller, E A; Yurkov, M V

2003-01-01

292

Applications of the Monte Carlo method in radiation protection  

International Nuclear Information System (INIS)

This paper gives a brief introduction to the application of the Monte Carlo method in radiation protection. It may be noted that an exhaustive review has not been attempted. The special advantage of the Monte Carlo method has been first brought out. The fundamentals of the Monte Carlo method have next been explained in brief, with special reference to two applications in radiation protection. Some sample current applications have been reported in the end in brief as examples. They are, medical radiation physics, microdosimetry, calculations of thermoluminescence intensity and probabilistic safety analysis. The limitations of the Monte Carlo method have also been mentioned in passing. (author)

293

Radiation ecology. Devices and methods of dosimetry  

International Nuclear Information System (INIS)

Radiation ecology problems as well as instruments and techniques applied in the dosimetry are considered. A concept of a maximum permissible dose for different population groups is presented. Three basic groups of critical organs are enumerated. A special attenuation is paid to the dosimetric monitoring of nuclear power plants and environment on a 10-12 km radius from the NPP

294

Electron cascades in sensors for optical detection of ionizing radiation  

Energy Technology Data Exchange (ETDEWEB)

A new class of high-speed detectors, called RadOptic detectors, measures ionizing radiation incident on a transparent semiconductor by sensing changes in the refractive index with an optical probe beam. We describe the role of radiation-initiated electron cascades in setting the sensitivity and the spatial and temporal resolution of RadOptic detectors. We model electron cascades with both analytical and Monte Carlo computational methods. We find that the timescale for the development of an electron cascade is less than of order 100 fs and is not expected to affect the time response of a detector. The characteristic size of the electron cloud is typically less than 2 ?m, enabling high spatial resolution in imaging systems. The electron-hole pair density created by single x-rays is much smaller than the saturation density and, therefore, single events should not saturate the detector.

London, Richard A.; Lowry, Mark E.; Vernon, Stephen P.; Stewart, Richard E. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2013-10-21

295

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

296

Development of nondestructive evaluation method on radiation damage using micromagnetic methods  

International Nuclear Information System (INIS)

The nuclear reactor pressure vessel is degraded by the high energy neutron bombardments during operation periods. Life extension of existing nuclear power plants requires the development of innovative NDE techniques for inspection of aged components. The magnetic method has been recently demonstrated as a promising technique. One major difficulty in using these particular techniques is to correlate the changes in the measured NDT signals with the microstructural changes occurred in the material due to aging. This problem may be solved through careful microstructural examinations of materials damage and introduction of signal analysis techniques. The NDE and science research center (NDE and S-RC) established in the Iwate University is studying about the application of minor loop method to the radiation damage. The minor loop technique in the detection of radiation damage is complement method of Barkhausen noise which developed in the Korea Atomic Energy Research Institute (KAERI). The cooperation between NDE and S-RC and KAERI are very important in the development of magnetic NDE techniques. The aim of this joint project will be the investigation of the magnetic properties for commen specimens using original methods, establishment of the fundamentals of magnetic NDE technique, and ensuring a safe operation of nuclear power plants

297

Robust Eye and Pupil Detection Method for Gaze Tracking  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

298

Development of damage evaluation method considering radiation induced stress relaxation  

International Nuclear Information System (INIS)

In this study, we evaluated the dependence of dose and irradiation temperature on radiation hardening (RH), radiation induced segregation (RIS), radiation induced stress relaxation (RISR), swelling and corrosion characteristics of austenitic stainless steel irradiated by using ion accelerators with and without bending displacement constraint. Considering the effect of bending displacement constraint on damage phenomena, a concept of new evaluation method for materials damage was considered to apply to the structural design of components. (author)

299

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

300

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

 
 
 
 
301

Scintillator's sensitivity calibration method in synchrotron radiation facility  

International Nuclear Information System (INIS)

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

302

Recent developments in radio-analytic methods for radiation protection. A resume  

International Nuclear Information System (INIS)

The review covers recent developments in radio-analytic methods for radiation protection. Te validation and verification of radio-analytic methodologies for radionuclide determination in a variety of matrices is related to the appropriate sample preparation. Modern techniques are described from rotation evaporators, microwave systems to automated separation columns. New testing technologies allow the extension of detectable radionuclides and to reduce the detection limit significantly. These techniques are of importance for incorporation surveillance purposes but also for emergency management in case of radiation accidents. The modern radio-analytical techniques allow a sophisticated quality assurance in the frame of international cooperation and projects. A specific contribution covers the capability of alpha spectrometry.

303

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

304

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

305

Recombination methods in the dosimetry of mixed radiation  

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-12-31

306

Synchrotron radiation basics, methods and applications  

CERN Document Server

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.

Boscherini, Federico; Meneghini, Carlo

2015-01-01

307

Establishment of the Radiation Detection Laboratory at Fisk University  

International Nuclear Information System (INIS)

Synthetic CdZnTe (CZT) semiconducting crystals are highly suitable for the room temperature-based detection of gamma radiation. The surface preparation of Au contacts on surfaces of CZT detectors is typically conducted after (1) polishing to remove artifacts from crystal sectioning and (2) chemical etching, which removes residual mechanical surface damage however etching results in a Te rich surface layer that is prone to oxidize. Our studies show that CZT surfaces that are only polished (as opposed to polished and etched) can be contacted with Au and will yield lower surface currents. Due to their decreased dark currents, these as-polished surfaces can be used in the fabrication of gamma detectors exhibiting a higher performance than polished and etched surfaces with relatively less peak tailing and greater energy resolution.

308

Detection of orphan radioactive sources during radiation monitoring  

International Nuclear Information System (INIS)

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

309

Radiation detection from phase-locked serial dc SQUID arrays  

DEFF Research Database (Denmark)

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

Mygind, Jesper; Pedersen, Niels Falsig

1993-01-01

310

Goals and methods of radiation risk estimation  

International Nuclear Information System (INIS)

The primary goal of general radiation protection rules as they are laid down in the recommendations of the ICRP and have been implemented in radiation protection regulations is to limit the risk incurred by professionally radiation exposed persons. This is the purpose of limit values, which in the case of stochastic risks relate to the effective dose. For reasons of practicability this approach necessitates certain simplifications. For example, tissue weighting factors are determined on the basis of averages across both sexes and all age groups. The ICRP gives nominal risk factors which differentiate only between the general population and the working population. Such simplifications are legitimate provided the conservativity principle is observed. For single-case estimates consideration must also be given to the specific exposure scenario in question as well as to the age at the time of exposure and at the time of diagnosis. Such estimates must always be based on organ dose values and specific age and sex dependent organ-related risks, as well as the uncertainty associated with each input parameter and estimated quantity. The generalised approach (based on values of effective dose) and the more specific approach lead to widely varying results, as is demonstrated by the examples presented in this paper. The paper closes with a discussion of the risks associated with X-ray diagnostics. Here too, though widespread, the use of the effective dose is inappropriate. Recent analyses have shown that this results in distorted risk estimates

311

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

312

Fluorescence in situ hybridisation in chromosome aberration detection in subjects occupationally exposed to ionising radiation  

International Nuclear Information System (INIS)

For more than two decades, chromosomal aberration analysis has been used to detect structural chromosomal aberrations as sensitive biodosimeters of occupational exposure to ionising radiation. Its use is also recommended by the World Health Organisation. Changes in chromosome structure detected by that method are considered to be early biomarkers of a possible malignant disease. Aberrations detected by the method are unstable and can be found in the lymphocytes of irradiated personnel only within a limited time after exposure. To detect stable chromosomal aberrations, which persist after exposure, multicolour fluorescent in situ hybridisation has to be used. Using DNA probes labelled with different fluorochromes, it dyes each pair of chromosomes with different colour. Due to the dynamic of unstable aberration formation, chromosomal aberration analysis is more suitable in genome damage assessment of recent exposures. On the other hand, fluorescence in situ hybridisation gives the information on chromosome instability caused by long-term occupational exposure to ionising radiation. Considering the high costs of fluorescence in situ hybridisation and the uncertainty of the result, it should be used in biodosimetry only when it is absolutely necessary.(author)

313

Technical improvement and development of automatic detection method for genomic mutation  

Energy Technology Data Exchange (ETDEWEB)

Aiming at automatic detection of genetic mutation, an investigation was made on sample preparing method for automatic detection and automatization of the preparing process. In this year, the second year of this research project, the chromosomal abnormalities in lymphocyte exposed to radiation were analyzed by highly accurate chromosome staining method to clarify the efficacy of the new staining method regarding dose effects, analyzing power for chromosomal abnormalities, etc. by comparing with the conventional method. Chromatin fibers of several hundred {mu} in length were found detectable by FISH, but the method was unsuitable for observation of the fibers in a nanometer level, suggesting that it is needed to prepare much purified samples through more complete deproteinization. Furthermore, primed in situ (PRINS) labelling method which targetted the repeated sequences in Y chromosome was found available for detecting chromatin fibers. (M.N.)

Yamada, Kiyomi; Takai, Setsuo; Togashi, Chikako; Itami, Jun [Research Inst. International Medical Center Japan, Tokyo (Japan)

1998-02-01

314

Technical improvement and development of automatic detection method for genomic mutation  

International Nuclear Information System (INIS)

Aiming at automatic detection of genetic mutation, an investigation was made on sample preparing method for automatic detection and automatization of the preparing process. In this year, the second year of this research project, the chromosomal abnormalities in lymphocyte exposed to radiation were analyzed by highly accurate chromosome staining method to clarify the efficacy of the new staining method regarding dose effects, analyzing power for chromosomal abnormalities, etc. by comparing with the conventional method. Chromatin fibers of several hundred ? in length were found detectable by FISH, but the method was unsuitable for observation of the fibers in a nanometer level, suggesting that it is needed to prepare much purified samples through more complete deproteinization. Furthermore, primed in situ (PRINS) labelling method which targetted the repeated sequences in Y chromosome was found available for detecting chromatin fibers. (M.N.)

315

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

316

Thermal radiation view factor calculation using Monte Carlo method  

International Nuclear Information System (INIS)

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

317

In-Situ Radiation Detection Demonstration Final Report  

International Nuclear Information System (INIS)

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

318

In-Situ Radiation Detection Demonstration Final Report  

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-06-01

319

UTILIZATION OF PHOSWICH DETECTORS FOR SIMULTANEOUS, MULTIPLE RADIATION DETECTION  

International Nuclear Information System (INIS)

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

320

Fiber-optic radiation sensor for detection of tritium  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-10-01

 
 
 
 
321

Biological detection of low radiation doses with integrated photothermal assay  

Science.gov (United States)

The goal of this paper was to evaluate the diagnostic value of integrated photothermal (PT) assay with additional fluorescent and photoacoustic (PA) modules to assess both the "safety limit" of exposure to ionizing ?-radiation and optimal therapeutic doses for cancer treatment. With this assay, the influences of ? irradiation on cancer cells (pancreatic-AR42J and hepatocytes-hepG2) and healthy cells (mouse lymphocytes and erythrocytes) was examined as a function of exposure dose (0.6-5 Gy) and time after irradiation, in vitro and in vivo. Independent verification of data obtained with conventional assays revealed that integrated PT assay allowed us to detect the different stages of radiation impact, including changes in cell metabolism at low dose, or stages related to cell death (apoptosis and necrosis) at high doses with a threshold sensitivity of at least three orders of magnitude better than existing assays. Also, PT assay was capable of quantitatively differentiating the biological action of ? irradiation alone and in combination with drug and nicotine impact. Finally, we demonstrated on an animal model that IPT assay has the potential for use in routine rapid evaluation of biological consequences of low-dose exposure a few days after irradiation.

Zharov, Vladimir P.; Viegas, Mark; Soderberg, Lee S. F.

2005-04-01

322

Modern Methods of Real-Time Gamma Radiation Monitoring for General Personal Protection  

Science.gov (United States)

Real-time radiation detectors become an essential part of emergency personnel who may have to respond to unknown accidents, incidents or terrorist attacks, which could involve radioactive material. More and more ordinary citizens are interested in personal radiation protection as well. Reasons include lost sources, nuclear industrial accidents, nuclear or radiological terrorism and the possibility of nuclear weapons being used in a war. People want to have the ability to measure it for themselves and they want to be notified when the radiation levels are increased. To meet this demand, considerable research into new sensors is underway, including efforts to enhance the sensor performance through both the material properties and manufacturing technologies. Deep understanding of physical properties of the materials under the influence of radiation exposure is vital for the effective design of dosimeter devices. Detection of radiation is based on the fact that both the electrical and the optical properties of the materials undergo changes upon the exposure to ionizing radiation. It is believed that radiation causes structural defects. The influence of radiation depends on both the dose and the parameters of the films including their thickness: the degradation is more severe for the higher dose and the thinner films. This paper presents overview of modern methods of real-time gamma radiation monitoring for personal protection of radiation workers and general public and suggests further developments in this area.

Korostynska, O.; Arshak, K.; Arshak, A.; Vaseashta, Ashok

323

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

324

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

325

Analysis on Credit Card Fraud Detection Methods  

Directory of Open Access Journals (Sweden)

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

Renu

2014-02-01

326

Background radiation dependence of detection and determination limits for a TLD reading system  

International Nuclear Information System (INIS)

The aim of the work is to study the detection and determination limits dependence of a TLD reading system on the time that dosemeters are exposed to the background radiation.A set of 15 TLD-100 (LiF:Mg,Ti) were exposed to the background radiation for periods of 15, 30, 45, 60, 90 and 180 days; the reading and the standard deviation were evaluated and from these data, using two simple models and the least square fit method, the detection and determination limits time dependence were calculated from the Hirning relations. From a radiation protection point of view when the reading of a dosemeter worn from a worker gives an air-kerma under, it is usually assigned an equivalent dose evaluated from LD so in the most case LD becomes a relevant part of the annual dose of a worker. In the present work we show that for small exposure times LD depends from the intrinsic properties of the system more than from the background radiation: so assigning an equivalent dose from LD we commit a systematic error that can be minimized increasing the time that the dosemeters are on the field. For our dosimetric system, consisting of a TLD-100 set of two-elements dosemeters and an Harshaw Model 6600 reading system, increasing the exposure time from 30 to 180 days can reduce the relative systematic error in the wrong assigned yearly dose from 153% to 13%. (authors)

327

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

Energy Technology Data Exchange (ETDEWEB)

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 {gamma}-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.

Zoleo, Alfonso, E-mail: alfonso.zoleo@unipd.it [Department of Chemical Sciences, University of Padova, via Marzolo 1, I-35131 Padova (Italy); Bortolussi, Claudia, E-mail: claudia.bortolussi@studenti.unipd.it [Department of Chemical Sciences, University of Padova, via Marzolo 1, I-35131 Padova (Italy); Brustolon, Marina, E-mail: marinarosa.brustolon@unipd.it [Department of Chemical Sciences, University of Padova, via Marzolo 1, I-35131 Padova (Italy)

2011-08-15

328

Discrete Event Simulation Modeling of Radiation Medicine Delivery Methods  

International Nuclear Information System (INIS)

The primary objective of this work was to evaluate the feasibility of using discrete event simulation (DES) modeling to estimate the effects on system performance of changes in the human, hardware, and software elements of radiation medicine delivery methods

329

Radiation sterilization as compared with another methods of making sterile  

International Nuclear Information System (INIS)

Presentation is devoted to sterilization and hygienization of food, medicinal articles and cosmetics. Radiosterilization is compared with other methods. Advantages of fast electron - and gamma radiation sterilization are stressed

330

Extract interaction detection methods from the biological literature  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background Considerable efforts have been made to extract protein-protein interactions from the biological literature, but little work has been done on the extraction of interaction detection methods. It is crucial to annotate the detection methods in the literature, since different detection methods shed different degrees of reliability on the reported interactions. However, the diversity of method mentions in the literature makes the automatic extraction quite chal...

Zhu Xiaoyan; Huang Minlie; Wang Hongning

2009-01-01

331

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)

332

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

333

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

334

Method of radiation degradation of PTFE under vacuum conditions  

International Nuclear Information System (INIS)

A new method of radiation degradation of Polytetrafluoroethylene (PTFE) under vacuum conditions is considered in this report. The combination of glow gas discharge and electrical surface discharge (on surface and inside PTFE) increases the efficiency of thermal-radiation degradation. The main mechanism of this degradation method consists of the breaking of C-C and C-F bonds. The vacuum conditions allow decreasing of the concentration of toxic compounds, such as a HF. Experimental results for degradation of PTFE are presented

335

EPR spectroscopy for the detection of foods treated with ionising radiation  

International Nuclear Information System (INIS)

The advantage of electron paramagnetic resonance spectroscopy (EPR or ESR) as a tool for the control of irradiated food lies in its sensitivity and accuracy. Ionising radiation produces, in irradiated materials, paramagnetic species of different kinds, i.e. radicals, radical-ions and paramagnetic centres, which can be measured by EPR but most of them are not stable enough to be used for the detection of irradiation. It is because radiation-induced paramagnetic species are thermodynamically less stable than surrounding molecules and take part in fast radiolytic reactions leading to the formation of final diamagnetic products that they are not detectable by the EPR method. Most of organic radicals produced by radiation in the liquid phase ae unstable but if the unpaired electron is incorporated into the complex polymeric system as in peptides and polysaccharides and is structurally isolated from the water, its stability is markedly increased. Since 1954 it is known that ionising radiation produces paramagnetic entities in biological materials, cells and tissues and some are stable enough to be observed by EPR spectroscopy at room temperature. The present paper describes and discusses that part of results obtained by this group during the period of ADMIT activity (1989-94) which are original and may be useful to those who will be working in the near future on the development of uniform control systems for the detection of irradiated food. The intention was to focus attention on these facts and data which influence the certainty of the detection in both positive and negative manner. (author)

336

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

337

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

338

Radiative Transfer in Star Formation: Testing FLD and Hybrid Methods  

Science.gov (United States)

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.; Ercolano, Barbara; Clarke, Cathie J.

339

Review on Islanding Detection Methods for Photovoltaic Inverter  

Directory of Open Access Journals (Sweden)

Full Text Available Solar power generation, which is regarded as an ideal environment-friendly manner for power generation, is getting more and more attention. When photovoltaic inverter is connected to the grid?the island effect is a special problem to confront. This paper briefly analyzes the island effects and makes a summary of both domestic and external research progress concerning islanding detection methods; the islanding detection methods can be divided into two classes: one is grid-side detection; the other is local detection. The local detection is generally divided into passive methods and active methods. The theory of advantages and disadvantages of those methods are briefly introduced in this paper. At the end of the paper, to deal with the disadvantages of those methods that are mentioned, it proposes the research direction for deeper study of islanding detection methods.

Liu Mochen

2013-07-01

340

The photochemical method for radiation abatement  

International Nuclear Information System (INIS)

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

 
 
 
 
341

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

342

Two-Dimensional Change Detection Methods Remote Sensing Applications  

CERN Document Server

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

Ilsever, Murat

2012-01-01

343

Network Traffic Anomalies Detecting Using Maximum Entropy Method  

Directory of Open Access Journals (Sweden)

Full Text Available The problem of traffic anomalies in computer networks is analyzed. NetFlow packets are used as network traffic data and maximum entropy methods is used for anomalies detection. Method detects network anomalies by comparing the current network traffic against a baseline distribution. Method is adopted according to NetFow data and performace of the method is improved. Prototype of anomalies detection system was developed and experimental investigation carried out. Results of investigation confirmed that method is sensitive to deviations of the network traffic and can be successfully used for network traffic anomalies detection.

Dalius Mažeika

2014-05-01

344

Extragalactic filament detection with a layer smoothing method  

CERN Document Server

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

Tugay, Anatoliy V

2014-01-01

345

Method of radiation therapy treatment planning  

International Nuclear Information System (INIS)

A technique of radiation therapy treatment planning designed to allow the assignment of dosage limits directly to chosen points in the computer-displayed cross-section of the patient. These dosage limits are used as constraints in a linear programming attempt to solve for beam strengths, minimizing integral dosage. If a feasible plan exists, the optimized plan will be displayed for approval as an isodose pattern. If there is no feasible plan, the operator/therapist can designate some of the point dosage constraints as ''relaxed.'' Linear programming will then optimize for minimum deviation at the relaxed points. This process can be iterated and new points selected until an acceptable plan is realized. In this manner the plan is optimized for uniformity as well as overall low dosage. 6 claims, 6 drawing figures

346

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

347

New developments in radiation protection instrumentation via active electronic methods  

International Nuclear Information System (INIS)

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

348

Method for non-invasive detection of ocular melanoma  

Science.gov (United States)

An apparatus and method is disclosed for diagnosing ocular cancer that is both non-invasive and accurate. The apparatus comprises two radiation detectors positioned before each of the patient's eyes which will measure the radiation level produced in each eye after the administration of a tumor-localizing radiopharmaceutical such as gallium-67. 2 figs.

Lambrecht, R.M.; Packer, S.

1984-10-30

349

Discontinuous Galerkin Methods for Computational Radiation Transport  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Merton, Simon Richard

2012-01-01

350

A back-scattering contraband detection method  

International Nuclear Information System (INIS)

A portable back-scattering detector using 133Ba as the radiation source is described. The detector can find out whether there is contraband in a hidden space. Some information about the type of the contraband can be given according to the back-scattering spectra. The prototype design of the detector is described, MCNP simulation and physics analysis based on a simplified model is done, and some experiment results are also given. (authors)

351

Nuisance Source Population Modeling for Radiation Detection System Analysis  

Energy Technology Data Exchange (ETDEWEB)

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 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.

Sokkappa, P; Lange, D; Nelson, K; Wheeler, R

2009-10-05

352

Radiation methods for liquid waste processing and ecological problems  

International Nuclear Information System (INIS)

Promissing trends in radiation application aimed at rational use of surface waters and their protection from contamination are set forth. Investigations in the USSR, USA and other countries have shown that use of radiation methods for processing allowed to succossfully settle at once several important problems of biosphere basic element conservation. Protection of the natural water reserviors and reduction consumption of fresh water used in industry are possible due to arrangement of water recirculation cycles. Radiation-prolonged adsorption appears to be rather promissing. Attention is paid to radiation processing of industrial and livestock wastes as well as activated sludge of biological sewage works for the pUrpose of their utilization. Radiation processing is used to eliminate waste release into the atmosphere resulting from ''processing'' contaminated effluents containing cancerogenic and toxic agents

353

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

International Nuclear Information System (INIS)

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

354

Radiation flaw detection in the USSR within the period of 30 years  

International Nuclear Information System (INIS)

Application of radioactive source in industry for defectoscopy purposes is discussed, and the trends of investigations are determined. The investigation results allowed one to develop a technique for nondestructive control of the quality of welding, rolling, casting and other engineering processes for the analysis of working state for complex units and aggregates, and detection of internal defects under specific conditions (in plants, in the field etc.). The results are reported of applying the radioscopy methods for controlling the quality of products and technique for their manufacture, development of radiometric defectoscopes, semiconductor detectors, manydetector systems, and automation of radiation-defectoscopic control

355

Electric field detection of coherent synchrotron radiation in a storage ring generated using laser bunch slicing  

International Nuclear Information System (INIS)

The electric field of coherent synchrotron radiation (CSR) generated by laser bunch slicing in a storage ring has been detected by an electro-optic sampling method. The gate pulses for sampling are sent through a large-mode-area photonic-crystal fiber. The observed electric field profile of the CSR is in good agreement with the spectrum of the CSR observed using Fourier transform far-infrared spectrometry, indicating good phase stability in the CSR. The longitudinal density profiles of electrons modulated by laser pulses were evaluated from the electric field profile.

356

Electric field detection of coherent synchrotron radiation in a storage ring generated using laser bunch slicing  

Science.gov (United States)

The electric field of coherent synchrotron radiation (CSR) generated by laser bunch slicing in a storage ring has been detected by an electro-optic sampling method. The gate pulses for sampling are sent through a large-mode-area photonic-crystal fiber. The observed electric field profile of the CSR is in good agreement with the spectrum of the CSR observed using Fourier transform far-infrared spectrometry, indicating good phase stability in the CSR. The longitudinal density profiles of electrons modulated by laser pulses were evaluated from the electric field profile.

Katayama, I.; Shimosato, H.; Bito, M.; Furusawa, K.; Adachi, M.; Shimada, M.; Zen, H.; Kimura, S.; Yamamoto, N.; Hosaka, M.; Katoh, M.; Ashida, M.

2012-03-01

357

Method for radiation production of fuels  

International Nuclear Information System (INIS)

A new improved chemical method for combustible fuel production by radiolysis of carbon dioxide in the presence of sulfur hexafluoride and NO2 is described. The dissociated products of carbon monoxide and oxygen may be recovered and used to produce hydrogen gas which can be converted to combustible fuels e.g. methane and methanol

358

Method of Object Detection for Mobile Robot  

Directory of Open Access Journals (Sweden)

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

Surachai Panich

2010-01-01

359

An Empirical Subspace Detection Method for Earthquakes  

Science.gov (United States)

Subspace detection uses the singular value decomposition of a design set of waveforms to find orthonormal representations (left singular vectors) that portray common characteristics of the seismograms. The first singular vector carries the dominant information common to the group of events, and as a result, closely resembles the stack of the design set. For a dense cluster of earthquakes, the second singular vector contains information representative of slight offsets in event location. This vector closely resembles the time derivative of the stack. Successive singular vectors contain information that is less important to representing the entire group. The singular vectors can be scanned through a continuous record, much like template matching, to identify earthquakes missing from the catalog. We use an empirical representation of the subspace by building a matrix comprised of two rows: the stack and the stack derivative, weighted by their respective singular values, to scan through the continuous catalog. We show an application to a Southern California sequence in which the use of an empirical subspace detects more uncataloged events with a lower false detection than using a stack alone. We suggest that template detection might be improved by using a matrix of the template and its time derivative with minor additional computational cost.

Barrett, S. A.; Beroza, G. C.

2013-12-01

360

Development and Establishment of Detection Method of Irradiated Foods  

International Nuclear Information System (INIS)

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

 
 
 
 
361

Radionuclide methods of detecting acute gastrointestinal bleeding  

International Nuclear Information System (INIS)

It is clinically very important to localize the bleeding site in suspected patients. Current common diagnostic methods are endoscopic, angiographic, and radionuclidic. Of the noninvasive procedures, 99mTc-RBC and 99mTc-colloid methods have gained wide popularity. In our series of a comparative study, the RBC method has been shown to be more accurate than the colloid method. The 99mTc-RBC method should be available as a routine emergency procedure in every large clinical center. (author)

362

Neutron Detection and Radiation Monitoring For The Egyptian Research Reactor (ETRR-1)  

International Nuclear Information System (INIS)

The detection of neutrons inside the reactor core is very important for the control, utilization and safety of nuclear reactors. Also, the radiation monitoring system was designed to allow continuous monitoring of radiation levels outside the nuclear reactors. We will illustrate the various types and function of the neutron detection system and the modernized radiation monitoring system which are used in the Egyptian research reactor (ETRR-1)

363

Radiative Transfer in Star Formation: Testing FLD and Hybrid Methods  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 th...

Owen, James E.; Ercolano, Barbara; Clarke, Cathie J.

2012-01-01

364

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.)

365

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)

366

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

Directory of Open Access Journals (Sweden)

Full Text Available In this research work, a face detection method is presented. Face detection is the first step of face Recognition methods. Face detection is a difficult task in Pattern. There are different methods of face detection namely-Knowledge Based Face Detection Methods, Feature Based Face Detection Methods, Template Based Face Detection Methods and Appearnce Based Face Detection Methods. But here we divided basically in two methods for face detection (i image based methods (ii feature based methods. We have developed an intermediate system, using a boosting algorithm to train a classifier which is capable of processing images rapidly while having high detection rates. AdaBoost is a kind of large margin classifiers and is efficient for on-line learning. In order to adapt the AdaBoost algorithm to fast face recognition, the original Adaboost which uses all given features is compared with the boosting along feature dimensions. The comparable results assure the use of the latter, which is faster for classification. The main idea in the building of the detector is a learning algorithm based on boosting: AdaBoost. AdaBoost is an aggressive learning algorithm which produces a strong classifier by choosing visual features in a family of simple classifiers and combining them linearly. The family of simple classifiers contains simple rectangular wavelets which are reminiscent of the Haar basis. Their simplicity and a new image representation called Integral Image allow a very quick computing of these Haarlike features. Then a structure in cascade is introduced in order to reject quickly the easy to classify background regions and focus on the harder to classify windows . For this, classifiers with an increasingly complexity are combined sequentially. This improves both, the detection speed and the detection efficiency. The detection of faces in input images is proceeded using a scanning window at different scales which permits to detect faces of every size without resampling the original image. On the other hand, the structure of the final classifier allows a realtime implementation of the detector. Due to some limitation of neural network based methods we adopt the Adaboost algorithm for face detection. Here we present Some results on real world examples are presented. Our detector found good detection rates with frontal faces and the method can be easily adapted to other object detection tasks by changing the contents of the training dataset.

Sushma Jaiswal

2011-08-01

367

Frontal Face Detection Methods –Neural Networks and Aggressive Learning Algorithm  

Directory of Open Access Journals (Sweden)

Full Text Available In this research work, a face detection method is presented. Face detection is the first step of face Recognition methods. Face detection is a difficult task in Pattern. There are different methods of face detection namely-Knowledge Based Face Detection Methods, Feature Based Face Detection Methods, Template Based Face Detection Methods and Appearnce Based Face Detection Methods. But here we divided basically in two methods for face detection (i image based methods (ii feature based methods. We have developed an intermediate system, using a boosting algorithm to train a classifier which is capable of processing images rapidly while having high detection rates. AdaBoost is a kind of large margin classifiers and is efficient for on-line learning. In order to adapt the AdaBoost algorithm to fast face recognition, the original Adaboost which uses all given features is compared with the boosting along feature dimensions. The comparable results assure the use of the latter, which is faster for classification. The main idea in the building of the detector is a learning algorithm based on boosting: AdaBoost. AdaBoost is an aggressive learning algorithm which produces a strong classifier by choosing visual features in a family of simple classifiers and combining them linearly. The family of simple classifiers contains simple rectangular wavelets which are reminiscent of the Haar basis. Their simplicity and a new image representation called Integral Image allow a very quick computing of these Haarlike features. Then a structure in cascade is introduced in order to reject quickly the easy to classify background regions and focus on the harder to classify windows . For this, classifiers with an increasingly complexity are combined sequentially. This improves both, the detection speed and the detection efficiency. The detection of faces in input images is proceeded using a scanning window at different scales which permits to detect faces of every size without resampling the original image. On the other hand, the structure of the final classifier allows a realtime implementation of the detector. Due to some limitation of neural network based methods we adopt the Adaboost algorithm for face detection. Here we present Some results on real world examples are presented. Our detector found good detection rates with frontal faces and the method can be easily adapted to other object detection tasks by changing the contents of the training dataset.

sushma jaiswal

2011-08-01

368

Research on development of high performance radiation detection technology and its application  

International Nuclear Information System (INIS)

At present, the detector with highest energy resolution among general purpose radiation detectors is semiconductor detector, but its resolution has approached the theoretical limit by the improvement. It is the actual state that remarkable technical innovation has not been carried out for the last more than ten years for radiation detectors. In this research, in order to develop the radiation detector based on new principle, the development of the detector utilizing superconducting tunnel joint (STJ) element has been advanced. In parallel, the development of superconducting materials has been carried out. The principle of X-ray detection is explained. Based on the established Josephson element technology, Nb system STJ element was made, and the evaluation of its characteristics was performed. The experimental study for detecting X-ray with it was carried out. The method of making the STJ element is reported. The joint structure of single crystal superconducting film is being developed. The evaluation of the characteristics of the STJ element is in progress. (K.I.)

369

Radiation Source Mapping with Bayesian Inverse Methods  

Science.gov (United States)

We present a method to map the spectral and spatial distributions of radioactive sources using a small number of detectors. Locating and identifying radioactive materials is important for border monitoring, accounting for special nuclear material in processing facilities, and in clean-up operations. Most methods to analyze these problems make restrictive assumptions about the distribution of the source. In contrast, the source-mapping method presented here allows an arbitrary three-dimensional distribution in space and a flexible group and gamma peak distribution in energy. To apply the method, the system's geometry and materials must be known. A probabilistic Bayesian approach is used to solve the resulting inverse problem (IP) since the system of equations is ill-posed. The probabilistic approach also provides estimates of the confidence in the final source map prediction. A set of adjoint flux, discrete ordinates solutions, obtained in this work by the Denovo code, are required to efficiently compute detector responses from a candidate source distribution. These adjoint fluxes are then used to form the linear model to map the state space to the response space. The test for the method is simultaneously locating a set of 137Cs and 60Co gamma sources in an empty room. This test problem is solved using synthetic measurements generated by a Monte Carlo (MCNP) model and using experimental measurements that we collected for this purpose. With the synthetic data, the predicted source distributions identified the locations of the sources to within tens of centimeters, in a room with an approximately four-by-four meter floor plan. Most of the predicted source intensities were within a factor of ten of their true value. The chi-square value of the predicted source was within a factor of five from the expected value based on the number of measurements employed. With a favorable uniform initial guess, the predicted source map was nearly identical to the true distribution, and the source intensities agreed within the predicted uncertainty. Using experimental data, the mapping was more difficult due to laboratory limitations. However, by supplanting 14 flawed measurements (out of 69 total) with synthetic data, the proof-of-principle source mapping was nearly as accurate as the synthetic-only prediction.

Hykes, Joshua Michael

370

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

International Nuclear Information System (INIS)

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

371

Detection method for amount of captured sludge  

International Nuclear Information System (INIS)

A distortion amount of a rotational vessel due to a centrifugal force is measured, and a weight of sludges captured in the rotational vessel is determined based on the ratio between the distortion amount and a previously formed calibration curve. In a centrifugal type solid/liquid separator having a vertical and open bottom type rotational vessel, the rotational vessel under operation is distorted so as to bulge outwardly. A strain gage is appended to the rotational vessel, and a device comprising a circuit for supplying current to a bridge circuit, a signal amplifying circuit and a signal electric wave generation circuit is provided. The device is integrally attached to a rotational shaft disposed, for example, above a radiation shielding plug, which hardly undergoes influences of radiation rays. A lead wire of the strain gage is laid passing through a hollow shaft. In addition, a circuit for receiving signals and taking outputs is disposed at a not-rotating portion apart from the shaft. Then, the distortion amount of the rotational vessel is measured by the strain gage, which is compared with a previously formed calibration curve for the distortion amount and the amount of the accumulated sludges, so that the amount of the captured sludges can be determined in the operation state. (N.H.)

372

An edge detection method for strong noisy image using shearlets  

Science.gov (United States)

Numerous edge detection methods have been proposed to detect image edges. However, these methods are not very effective in detecting edges in strong noisy images. Recent years, multiscale analysis has been introduced to the realm of image processing. As the third generation wavelet, shearlets have their own superiority. Anisotropic dilation operator and shear operator are introduced to overcome the shortcomings of traditional wavelets. Because of their sensitivity to directions, shearlets are apt to do the job of edge detection. Based on shearlets, in this paper, a new edge detection method is proposed. The main idea about this new method is combining the shearlet denoising method with the edge detecting method based on shearlets. Analyzing results show that edges are characterized as zerocrossing points in shearlet domain and can be extracted from shearlet transform coefficients by detecting zero crossing points and using boundary tracking method. Many experiments are conducted to test this novel approach and we also compare Sobel, Log and Canny operators with this new method. Experiments demonstrate that when an image existing high deviation Gaussian noise, this method are much better than ordinary edge detection operators in time domain.

Li, Yuming; Cao, Hanqiang; Xu, Zijian

2011-11-01

373

Contour Integral Method for Crack Detection  

International Nuclear Information System (INIS)

In this paper, a new approach to detect surface cracks from a noisy thermal image in the infrared thermography is presented using an holomorphic characteristic of temperature field in a thin plate under steady-state thermal condition. The holomorphic function for 2-D heat flow field in the plate was derived from Cauchy Riemann conditions to define a contour integral that varies according to the existence and strength of a singularity in the domain of integration. The contour integral at each point of thermal image eliminated the temperature variation due to heat conduction and suppressed the noise, so that its image emphasized and highlighted the singularity such as crack. This feature of holomorphic function was also investigated numerically using a simple thermal field in the thin plate satisfying the Laplace equation. The simulation results showed that the integral image selected and detected the crack embedded artificially in the plate very well in a noisy environment

374

Use of microorganisms for detection of Vavilov-Cherenkov radiation  

International Nuclear Information System (INIS)

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

375

Novel Methods To Detect Membrane Proteins  

Science.gov (United States)

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

376

Alternative Detection Methods for Highest Energy Neutrinos  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Several experimental techniques are currently under development, to measure the expected tiny fluxes of highest energy neutrinos above 10**18 eV. Projects in different stages of realisation are discussed here, which are based on optical and radio as well as acoustic detectors. For the detection of neutrino events in this energy range a combination of different detector concepts in one experiment seems to be most promising.

Nahnhauer, Rolf

2004-01-01

377

Detection of formaldehyde in textiles by chromotropic acid method  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Rao Sanath; Shenoy Shruthakirthi; Davis Suraj; Nayak Sudhakar

2004-01-01

378

Detecting community structure in networks using edge prediction methods  

CERN Document Server

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

Yan, Bowen

2012-01-01

379

Time Resolved Detection of Infrared Synchrotron Radiation at DA?NE  

International Nuclear Information System (INIS)

Synchrotron radiation is characterized by a very wide spectral emission from IR to X-ray wavelengths and a pulsed structure that is a function of the source time structure. In a storage ring, the typical temporal distance between two bunches, whose duration is a few hundreds of picoseconds, is on the nanosecond scale. Therefore, synchrotron radiation sources are a very powerful tools to perform time-resolved experiments that however need extremely fast detectors. Uncooled IR devices optimized for the mid-IR range with sub-nanosecond response time, are now available and can be used for fast detection of intense IR sources such as synchrotron radiation storage rings. We present here different measurements of the pulsed synchrotron radiation emission at DA?NE (Double Annular ?-factory for Nice Experiments), the collider of the Laboratori Nazionali of Frascati (LNF) of the Istituto Nazionale di Fisica Nucleare (INFN), performed with very fast uncooled infrared detectors with a time resolution of a few hundreds of picoseconds. We resolved the emission time structure of the electron bunches of the DA?NE collider when it works in a normal condition for high energy physics experiments with both photovoltaic and photoconductive detectors. Such a technology should pave the way to new diagnostic methods in storage rings, monitoring also source instabilities and bunch dynamics

380

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

 
 
 
 
381

High Density Nano-Electrode Array for Radiation Detection  

International Nuclear Information System (INIS)

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

382

GaN heterostructures for biosensing and radiation detection  

Energy Technology Data Exchange (ETDEWEB)

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

Howgate, John D.

2012-12-11

383

Robust Automatic Facial Expression Detection Method  

Directory of Open Access Journals (Sweden)

Full Text Available Recently, the recognition of occluded facial expressions attract more and more people’s attention. Sparse representation based classification (SRC method gives good performance on face recognition (FR and facial expression recognition (FER, well-known for its robustness to occlusion. Histograms of Oriented Gradient (HOG descriptors are very efficient to represent the shape information of different facial expressions and robust to various illumination. Since, this paper proposes a novel method by using HOG descriptors conjunction with SRC framework for FER. Experiment results show that the proposed method gives better performance than the existing state-of-the-art methods. Furthermore, the proposed method is not only robust to assigned occlusions, but also to random occlusions.

Yan OuYang

2013-07-01

384

Resonance differential method for detection of molecular iodine in atmosphere  

International Nuclear Information System (INIS)

Possibility of using vibrational structure of I2 absorption spectra to detect molecular iodine in atmosphere is shown. Resonance differential detection method based on ''deep'' spectral modulation of I2 absorption spectra section having quasiregular vibrational structure is suggested. Direct measurement of the amount of I2 content in Leningrad atmosphere is carried out. The suggested method is realized using laboratory-scale plant

385

Robust Eye and Pupil Detection Method for Gaze Tracking  

Directory of Open Access Journals (Sweden)

The experimental results show that the proposed method can detect the center of the pupil at a speed of approximately 19.4 frames/s with an RMS error of approximately 5.75 pixels, which is superior to the performance of conventional detection methods.

Su Yeong Gwon

2013-02-01

386

Method of cleaning radiation-contaminated clothes  

International Nuclear Information System (INIS)

Purpose: To attain effective cleaning while preventing cross-contamination. Method: Radioactive-contaminated clothes are measured for the dose and divided into high contaminated matters and less contaminated matters. Then, high contaminated matters are washed using a mixed detergent comprising an anionic surfactant (such as polyoxyethylenealkyl ether sodium sulfate or the like) and a chelating agent (such as EDTA, condensate of naphthalene sulfonic acid and formalin), while less contaminated matters are washed only with the non-ionic surfactant. This can prevent cross-contamination to thereby facilitate liquid waste treatment and improve the washing efficiency. Furthermore, since no phosphoric-compounded detergent is not used, generation of scales upon liquid wastes disposal can be prevented. (Sekiya, K.)

387

On the acoustic leak detection method in piping system  

International Nuclear Information System (INIS)

Periodic inspection is carried out every year on the piping systems in reactor coolant pressure boundary, and leak detecting system is installed in a containment vessel, to confirm the soundness and to detect leak early in nuclear power stations. The leak detecting system comprises the measurements of the flow rate of floor drain and the temperature, humidity and radioactivity in the atmosphere. The method using the radioactivity in air is excellent in its response and detection sensitivity, but the limit of detection is about 100 cc/min, therefore the investigation of effective detection method is important. In this study, the basic investigation was made on the method of detecting the leak of steam and water in piping systems by detecting the noise arising at that time. When gas or liquid leaks through a small gap, the flow generates acoustic energy at the leaking part of a vessel and in the surrounding space. The noise generated at the leaking part and propagating through the vessel can be detected with an acoustic sensor attached to it, at a distant position. In this paper, the experimental study on this subject is reported. The experimental apparatus, the method of measurement and the experimental results are described. The sensitivity of detecting leak taking background noise into consideration was estimated, and the method of monitoring leak signals in the operation of actual plants was considered. (J.P.N.)

388

Rain-induced increase in background radiation detected by Radiation Portal Monitors.  

Science.gov (United States)

A complete understanding of both the steady state and transient background measured by Radiation Portal Monitors (RPMs) is essential to predictable system performance, as well as maximization of detection sensitivity. To facilitate this understanding, a test bed for the study of natural background in RPMs has been established at the Oak Ridge National Laboratory. This work was performed in support of the Second Line of Defense Program's mission to enhance partner country capability to deter, detect, and interdict the illicit movement of special nuclear material. In the present work, transient increases in gamma-ray counting rates in RPMs due to rain are investigated. The increase in background activity associated with rain, which has been well documented in the field of environmental radioactivity, originates primarily from the wet-deposition of two radioactive daughters of (222)Rn, namely, (214)Pb and (214)Bi. In this study, rainfall rates recorded by a co-located weather station are compared with RPM count rates and high-purity germanium spectra. The data verify that these radionuclides are responsible for the largest environmental background fluctuations in RPMs. Analytical expressions for the detector response function in Poly-Vinyl Toluene have been derived. Effects on system performance and potential mitigation strategies are discussed. PMID:25062116

Livesay, R J; Blessinger, C S; Guzzardo, T F; Hausladen, P A

2014-11-01

389

The detection of the environmental radiation for DIS and Luxel badge (OSLD)  

International Nuclear Information System (INIS)

Personal radiation dose has decreased as years pass by. This requires a personal dosemeter with higher sensitivity. Recently new dosemeters have been developed, such as the Luxel badge that is composed of Aluminium Oxide (Al2O3:C) as a detector element with an optically stimulated luminescence process for a measuring method, and the DIS dosemeter containing a MOSFET type analogue EEPROM. These dosemeters have 10 to 100 times lower detection limit than the old film badge. Then some trials have been conducted to use these dosemeters for measuring environmental doses. Here I will present the technical specifications like detection principles of these dosemeters and some examples of data obtained from application to the environmental dose measurement. (author)

390

System and method for detecting gas  

Science.gov (United States)

A system to detect a presence of a specific gas in a mixture of gaseous byproducts comprising moisture vapor is disclosed. The system includes an electrochemical cell, a transport to deliver the mixture of gaseous byproducts from the electrochemical cell, a gas sensor in fluid communication with the transport, the sensor responsive to a presence of the specific gas to generate a signal corresponding to a concentration of the specific gas, and a membrane to prevent transmission of liquid moisture, the membrane disposed between the transport and the gas sensor.

Chow, Oscar Ken (Simsbury, CT); Moulthrop, Lawrence Clinton (Windsor, CT); Dreier, Ken Wayne (Madison, CT); Miller, Jacob Andrew (Dexter, MI)

2010-03-16

391

Detection of dark-matter-radiation of stars during visible sun eclipses  

Energy Technology Data Exchange (ETDEWEB)

Recently a so-far unknown form of quantized, cold dark matter was detected on a laboratory scale which shows a complementary structure as compared to known forms of matter. From the experiments results that the observed quanta of the new type of matter as integer multiples of the Planck mass (mp = n {center_dot} {radical}((h{center_dot}c)/((2 {center_dot} {pi} {center_dot} G))) = n 0 21.77 {mu}g, with n = 1, 2, 3 etc.) exhibit a spatially extended 'field-like' structure ranging over distances of centimetres or more, opposite to the 'point-like' structure of the known elementary particles of the standard model. Association of quanta of the new form of 'soft' (or subtle) matter to clusters was observed, as well as re-clustering after absorption. Thus, between such quanta a physical interaction must exist. In addition, the new form of matter shows at least two interactions with normal matter, a gravitational one due to its real mass content and a so-far unknown 'topological', i.e. form-specific, interaction at phase borders. Additional indications for a weak electromagnetic interaction exist. Furthermore, the experimental results reveal that some types of quanta of the new form of 'field-like' matter exhibit positive mass, as normal matter, but others exhibit a negative mass content, both in the order of magnitude of the Planck mass. Memory effects in normal matter were detected after absorption of quanta of the new form of soft matter. In general, the findings characterize the quanta of 'fieldlike' matter as WIMP candidates of a cosmic background radiation of cold dark matter (quanta with positive mass) as well as of a cosmic background radiation of dark energy (quanta with negative mass). During visible sun eclipses in 1989, 1996 and. 1999, as well as during full moon of 6 January 2001, a so-far unknown form of dark-matter-radiation ('dark radiation') was detected. The quanta of this 'dark radiation' travel with the speed of light, but reveal macroscopic real mass, with positive and with negative mass content. The presented method of experimentation offers a so-far unknown form of astrophysical observation, based on dark matter detection.

Volkamer, Klaus E-mail: dr.volkamer@t-online.de

2003-07-01

392

Detection of VLF and ELF long path signals radiated from heated and modulated ionosphere current systems  

International Nuclear Information System (INIS)

This thesis describes the theoretical and experimental evidence of verified detection of very low frequency (VLF) and extremely low frequency (ELF) long-path signals radiated from a heated and modulated dynamo current system at mid-latitudes. A general background of the ionosphere current systems and prior research in VLF/ELF communications is followed by a complete description of the receiving subsystem. The on/off method of ionospheric heating with synchronous detection is the primary experimental technique. Phase reversal of the heating modulation envelope to create four-bit messages with synchronous averaging of the detected message is explained. A laboratory receiver subsystem calibration enables receiver system voltages to be related to the magnitude of the earth's horizontal magnetic field component at the receiving loop antenna. The laboratory calibration found a -20 dB threshold, below background noise level for detection of on/off type signals. This detection threshold was extended to -46.91 dB when 256 sample synchronous averaging was applied to four bit message data

393

A Comprehensive Simulation Method for Examining Radiation Belt Dynamics  

Science.gov (United States)

The particles comprising the Van Allen radiation belts are affected by a variety of electromagnetic and electrostatic waves present in the magnetosphere. For example, the Van Allen Probes mission has recently uncovered evidence for heating in the radiation belts as a result of local kHz wave-particle interactions, violating the cyclotron invariant. Similarly, global variations at mHz frequencies commensurate with the particle drift frequency can lead to effective transport, heating, and loss within the radiation belts as a result of changes to the third adiabatic invariant. The wide variety of waves occurring over this disparate frequency range presents a fundamental challenge in constructing dynamic models of the radiation belts. In this effort we present results from a new method for tracking the global dynamics of the radiation belts. Here we examine a well-observed flux dropout and subsequent acceleration event occurring on 20 September 2007. We use 3d magnetohydrodynamic (MHD) simulations of the solar wind/magnetospheric interaction to track particles in a bounce-averaged formalism, combined with stochastic differential equation (SDE) simulations of local wave-particle interactions, to provide a comprehensive model of the radiation belts encompassing both large-scale transport and local heating and loss within the radiation belts.

Elkington, S. R.; Chan, A. A.; Zheng, L.

2013-12-01

394

Radiation induced effects and annealing methods in fiberoptics and glasses  

International Nuclear Information System (INIS)

Radiation induced effects in glass-rods and fiberoptics have been studied to determine parameters affecting the application of these materials in nuclear technology, i.e. as fiberscopes for visual inspection in severe radiation environments. Different glass and fibertypes have been exposed to fission product gamma radiation. The radiation induced transmission loss was measured with a spectrophotometer and then different annealing methods were examined to improve the transmission properties again. Especially the changes in glass and fiber recovery vs. time as a function of radiation dose and annealing temperature were investigated. Annealing experiments were performed exposing the samples either to temperature treatment or to various light sources such as quartz lamp, arc lamp or UV-laser for optical annealing. The transmission recovery was then investigated either as a function of annealing temperature or of exposure time to the light sources. The results allow conclusions on the design and composition of optical fiber endoscopes to be used in severe radiation environment where image transmission is required in the presence of high level nuclear radiation. (author)

395

Methods and procedures for external radiation dosimetry at ORNL  

International Nuclear Information System (INIS)

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

396

Method for decreasing radiation load in puva therapy  

International Nuclear Information System (INIS)

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

397

Knowledge representation methods for early failure detection  

International Nuclear Information System (INIS)

To supervise technical processes like nuclear power plants, it is very important to detect failure modes in an early stage. In the nuclear research center at Karlsruhe an expert system is developed, embedded in a computer network of autonomous computers, which are used for intelligent prepocessing. Events, process data and actual parameter values are stored in slots of special frames in the knowledge base of the expert system. Both rule based and fact based knowledge representations are employed to generate cause consequence chains of failure states. By on-line surveillance of the reactor process, the slots of the frames are dynamically actualized. Immediately after the evaluation, the inference engine starts in the special domain experts (triggered by metarules from a manager) and detects the correspondend failures or anomaly state. Matching the members of the chain and regarding a catalogue of instructions and messages, what is to do by the operator, future failure states can be estimated and propagation can be prohibited. That means qualitative failure prediction based on cause consequence in the static part of the knowledge base. Also, a time series of physical data can be used to predict on analytical way future process state and to continue such a theoretical propagation with matching the cause consuquence chain

398

Effect of radiation sources, x-ray films and intensifying screens on detectability of defects  

International Nuclear Information System (INIS)

It has been empirically known so far that the degree of identifying defects is affected by the combination of radiation sources, X-ray films and intensifying screens. In this paper, the method of determining the discernible smallest wire diameter of wire type penetrameters that have been used as one means of evaluating the quality of radiographs by calculation and an example of the results are shown. Next, the results of taking the radiographs of the welded test pieces having internal defects by variously changing the combination of radiation sources, X-ray films and intensifying screens, this discerned smallest wire diameter and the results of the cutting test of the welded test pieces were matched. The contrast of radiographs, the contrast of discernible limit, the method of calculating discernible smallest wire diameter, the relation of the combination of radiation sources, X-ray films and intensifying screens with discernible smallest wire diameter, the comparison of the calculated result and the experimental result, the extent of detecting defects and so on are reported. As discernible smallest wire diameter is smaller, the form and dimensions of defect images become closer to the actual state of defects. (Kako, I.)

399

Assessment and comparison of methods for solar ultraviolet radiation measurements  

International Nuclear Information System (INIS)

In the study, the different methods to measure the solar ultraviolet radiation are compared. The methods included are spectroradiometric, erythemally weighted broadband and multi-channel measurements. The comparison of the different methods is based on a literature review and assessments of optical characteristics of the spectroradiometer Optronic 742 of the Finnish Centre for Radiation and Nuclear Safety (STUK) and of the erythemally weighted Robertson-Berger type broadband radiometers Solar Light models 500 and 501 of the Finnish Meteorological Institute and STUK. An introduction to the sources of error in solar UV measurements, to methods for radiometric characterization of UV radiometers together with methods for error reduction are presented. Reviews on experiences from world-wide UV monitoring efforts and instrumentation as well as on the results from international UV radiometer intercomparisons are also presented. (62 refs.)

400

Gold Cleaning Methods for Electrochemical Detection Applications  

DEFF Research Database (Denmark)

This work investigates methods for obtaining reliably clean gold film surfaces. Nine gold cleaning methods are investigated here: UV ozone photoreactor; potassium hydroxide-hydrogen peroxide; potassium hydroxide potential sweep; sulfuric acid hydrogen peroxide; sulfuric acid potential cycling; hydrochloric acid potential cycling; dimethylamine borane reducing agent solutions at 25 and 65 degrees C; and a dilute form of Aqua Regia. Peak-current potential-differences obtained from cyclic voltammetry and charge transfer resistance obtained from electrochemical impedance spectroscopy, as well as X-ray photo-electron spectroscopy are used to characterize surface cleanliness. A low peak-current potential-difference and charge transfer resistance indicates a cleaner surface, as does a higher percentage of elemental gold on the electrode surface. The potassium hydroxide potential sweep method is found to leave the gold surface the cleanest overall.

Fischer, Lee MacKenzie; Tenje, Maria

2009-01-01

 
 
 
 
401

A numerical method of detecting singularity  

Science.gov (United States)

A numerical method is reported which determines a value C for the degree of conditioning of a matrix. This value is C = 0 for a singular matrix and has progressively larger values for matrices which are increasingly well-conditioned. This value is C sub = C max sub max (C defined by the precision of the computer) when the matrix is perfectly well conditioned.

Laporte, M.; Vignes, J.

1978-01-01

402

[An automated method of detecting bacteriuria].  

Science.gov (United States)

A screening test for bacteriuria was developed, based on the use of the Bioscreen microbiological system (Labsystem, Finland) and nutrient media manufactured in the USSR. The diagnostic characteristics of the new test were assessed in screening of inpatients; the test has proved to be not inferior to similar methods realized in the microbiological systems manufactured in Western Europe and USA. PMID:1695266

Antonov, V S; Vlasenko, V I; Komleva, A A; Shibanov, A N; Rozental', V M; Starobina, A D; Tananaeva, I K

1990-01-01

403

Scintillation probe for the detection and measurement of radiation, for the determination of some cardiac parameters  

International Nuclear Information System (INIS)

The scintillation probe described is for the detection and measurement of radiation. It includes a transducer comprising several distinct optically isolated scintillation, in each one of which a luminous radiation is generated under the effect of incident radiation; a photodetector in optical communication with the scintillators so as to generate distinct electric signals for each scintillator, under the effect of the detection of a luminous radiation; a recording instrument to record the electric signals; and a collimator defining, for the various collimators, fields that overlap partially, so as to allow the separate recording of the electric signals resulting from radioactive occurences in an area of the particular space presenting some interest

404

Study on Thermal Conductivity Gas Sensor Constant Temperature Detection Method  

Directory of Open Access Journals (Sweden)

Full Text Available The thermal conductivity gas sensor can detect gas concentration that measure the thermal conductivity coefficient of the measured gas different from the background gas.This paper analyzes the theory of thermal conductivity gas sensor and method of measurement,proposes thermal conductivity gas sensor constant temperature detection method,and experimentally validate the feasibility of ambient temperature compensation. Experimental results show that the method effectively reduces the effect of ambient temperature on measuring accuracy.

Xi-bo Ding

2013-11-01

405

Efficient Estimation and Detection Methods for Airborne Applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The overall purpose with this thesis is to investigate and provide computationally efficient methods for estimation and detection. The focus is on airborne applications, and we seek estimation and detection methods which are accurate and reliable yet effective with respect to computational load. In particular, the methods shall be optimized for terrain-aided navigation andcollision avoidance respectively. The estimation part focuses on particle filtering and the in general much more efficient...

Nordlund, Per-johan

2009-01-01

406

Rapid radiometric method for detection of Salmonella in foods  

Energy Technology Data Exchange (ETDEWEB)

A radiometric method for the detection of Salmonella in foods has been developed which is based on Salmonella poly H agglutinating serum preventing Salmonella from producing 14CO2 from (14C) dulcitol. The method will detect the presence or absence of Salmonella in a product within 30 h compared to 4 to 5 days by routine culture methods. The method has been evaluated against a routine culture method using 58 samples of food. The overall agreement was 91%. Five samples negative for Salmonella by the routine method were positive by the radiometric method. These may have been false positives. However, the routine method may have failed to detect Salmonella due to the presence of large numbers of lactose-fermenting bacteria which hindered isolation of Salmonella colonies on the selective agar plates.

Stewart, B.J.; Eyles, M.J.; Murrell, W.G.

1980-08-01

407

Detection of volatile biomarkers of therapeutic radiation in breath.  

Science.gov (United States)

Breath testing could provide a rational tool for radiation biodosimetry because radiation causes distinct stress-producing molecular damage, notably an increased production of reactive oxygen species. The resulting oxidative stress accelerates lipid peroxidation of polyunsaturated fatty acids, liberating alkanes and alkane metabolites that are excreted in the breath as volatile organic compounds (VOCs). Breath tests were performed before and after radiation therapy over five days in 31 subjects receiving daily fractionated doses: 180-400 cGy d(-1) standard radiotherapy (n = 26), or 700-1200 cGy d(-1) high-dose stereotactic body radiotherapy (n = 5). Breath VOCs were assayed using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry. Multiple Monte Carlo simulations identified approximately 50 VOCs as greater-than-chance biomarkers of radiation on all five days of the study. A consistent subset of 15 VOCs was observed at all time points. A radiation response function was built by combining these biomarkers and the resulting dose-effect curve was significantly elevated at all exposures ?1.8 Gy. Cross-validated binary algorithms identified radiation exposures ?1.8 Gy with 99% accuracy, and ?5 Gy with 78% accuracy. In this proof of principal study of breath VOCs, we built a preliminary radiation response function based on 15 VOCs that appears to identify exposure to localized doses of 1.8 Gy and higher. VOC breath testing could provide a new tool for rapid and non-invasive radiation biodosimetry. PMID:23793046

Phillips, Michael; Byrnes, Richard; Cataneo, Renee N; Chaturvedi, Anirudh; Kaplan, Peter D; Libardoni, Mark; Mehta, Vivek; Mundada, Mayur; Patel, Urvish; Ramakrishna, Naren; Schiff, Peter B; Zhang, Xiang

2013-09-01

408

Detection device of dangerous radiation for the living beings  

International Nuclear Information System (INIS)

This invention is about a portable device able to measure dose rates or doses of gamma, ultraviolet and X radiation or charged particles. This device is composed of a radiation detector, a calculator of the accumulate dose and a memory to store the data. This device has a credit card format

409

Deep level impurities in semiconductors for nuclear radiation detection  

International Nuclear Information System (INIS)

Results of work on the behaviour of deep level impurities in the semiconductors Ge, Si and GaAs, within the context of solid-state nuclear radiation detectors, are reported. The main measurement technique used was deep level transient spectroscopy. Effects of lithium and hydrogen on gamma radiation damage have been investigated

410

Mesoscale detection, tracking and characterization of tornadoes by acoustic radiation  

Science.gov (United States)

Acoustic data recorded at 1000 samples per second from two acoustic sensor arrays located at ranges of 1 km to 113 km from three tornadoes that occurred on 24 May 2012 in Oklahoma, United States, are analyzed. Accurate bearings to the tornadoes have been obtained using beamforming methods applied to the data in the infrasonic band. Because of the spacing of the sensors, beamforming is not viable at audible frequencies, but the data demonstrate the ability to detect significant changes in the shape of the measured pressure power spectral density in the band encompassing 10 Hz to approximately 200 Hz. This suggests that arrays of more closely spaced sensors could provide even better bearing accuracy at practically useful distances from a tornado. Additionally, a mathematical model based on established relationships of aeroacoustic turbulence possessing only a few free parameters is demonstrated to provide good agreement to the measured power spectra from the three storms at different times and distances from the storms. The results of this analysis indicate that an inverse relationship exists between the frequency of the observed peak of the power spectral density in the audible band and the reported tornado intensity, thus implying that it might be possible to achieve real-time estimation of storm intensity via acoustic analysis methods.

Frazier, W. G.; Park, J. C.; Talmadge, C. L.; Waxler, R.; Assink, J. D.

2012-12-01

411

Methods of decreasing 137Cs minimum detectable activities in foodstuff samples  

International Nuclear Information System (INIS)

Monitoring of radionuclide content in foodstuffs in the Czech Republic (CR) has been provided by Radiation Monitoring Network (RMN) since 1986. This network in the normal operation mode is aimed at monitoring of actual radiation situation and at the early detection of radiation accidents. In present time determination of gamma-emitting radionuclides in foodstuffs and water samples is provided by a sub network consisted of seven laboratories equipped with semiconductor HPGe detectors (relative efficiency of 20-150 % ). The monitored foodstuff items include mainly various kinds of meet, vegetables, fruits, grain and grain products, milk and milk products, mushrooms, wild berries and honey .The results have been stored in a database system of RMN and have been available for statistical evaluation of the data. The annual reports concerning radiation situation in the CR have been provided by cooperation of National Radiation Protection Institute (SURO) in Prague and State Office for Nuclear Safety (SUJB). The actual values of Cs-137 specific activity in many samples are very low. The values lower than minimum detectable activities (MDA) represent significant part of the data for most foodstuff items. This fact complicates the statistical evaluation of the data. Some methods for decreasing of minimum detectable activities in foodstuff samples are presented. (authors)

412

[Simple and rapid detection methods for campylobacters].  

Science.gov (United States)

Campylobacter jejuni and Campylobacter coli have been leading cause of food poisoning in terms of both number of patients and cases in Japan. Therefore these bacteria are recognized as one of the most important food-borne pathogens. Since campylobacters are microaerobic, slow growing, biochemically unreactive, not only it takes some time but also there are several problems regarding isolation and identification of Campylobacter spp. We found that cytolethal distending toxin (cdt) genes are ubiquitously present in C. jejuni, C. coli and C. fetus in species-specific manner and species-specific multiplex PCRs have been developed on the basis of species-specificity of the cdt genes. In this review, applicability of the cdt gene-based multiplex PCRs as a simple and rapid diagnostic method for clinical and food samples in comparison to the conventional culture methods is described. PMID:22894063

Yamasaki, Shinji; Asakura, Masahiro; Shiramaru, Sachi; Inoue, Haruna

2012-08-01

413

A Novel Diagnostics of Ultrashort Electron Bunches Based on Detection of Coherent Radiation from Bunched Electron Beam in an Undulator  

CERN Document Server

We propose a new method for measurements of the longitudinal profile of 100 femtosecond electron bunches for X-ray Free Electron Lasers (XFELs). The method is based on detection of coherent undulator radiation produced by modulated electron beam. Seed optical quantum laser is used to produce exact optical replica of ultrashort electron bunches. The replica is generated in apparatus which consists of an input undulator (energy modulator), and output undulator (radiator) separated by a dispersion section. The radiation in the output undulator is excited by the electron bunch modulated at the optical wavelength and rapidly reaches a hundred-MW-level power. We then use the now-standard method of ultrashort laser pulse-shape measurement, a tandem combination of autocorrelator and spectrum (FROG -- frequency resolved optical gating) providing real-time single-shot measurements of the electron bunch structure. The big advantage of proposed technique is that it can be used to determine the slice energy spread and emi...

Saldin, Evgeny L; Yurkov, Mikhail V

2004-01-01

414

Heterodyne method for high specificity gas detection.  

Science.gov (United States)

This paper describes a new technique for measuring trace quantities of gases. The technique involves the use of a reference cell (containing a known amount of the gas being sought) and a sample cell (containing an unknown amount of the same gas) wherein the gas densities are modulated. Light passing through the two cells in sequence is modulated in intensity at the vibrational-rotational lines characteristic of the absorption spectrum for the gas of interest. Since the absorption process is nonlinear, modulating the two absorption cells at two different frequencies gives rise to a heterodyning effect, which in turn introduces sum and difference frequencies in the detected signal. Measuring the ratio of the difference frequency signal for example, to the signal introduced by the reference cell provides a normalized measure of the amount of the gas in the sample cell. The readings produced are thereby independent of source intensity, window transparency, and detector sensitivity. Experimental evaluation of the technique suggests that it should be applicable to a wide range of gases, that it should be able to reject spurious signals due to unwanted gases, and that it should be sensitive to concentrations of the order of 10 to the minus 8th power when used with a sample cell of only 20 cm length.

Dimeff, J.; Donaldson, R. W.; Gunter, W. D., Jr.; Jaynes, D. N.; Margozzi, A. P.; Deboo, G. J.; Mcclatchie, E. A.; Williams, K. G.

1971-01-01

415

Measures of lifetime detriment from radiation exposures: Principles and methods  

International Nuclear Information System (INIS)

This report presents the work initiated at the 'Workshop on the comparison of methods for deriving life long risk indices for the effects of ionizing radiations', organized by CEPN in Fontenay-aux-Roses (France), on August 7-11, 1989. It has been written in collaboration by participants during the following years

416

Method for producing bonded nonwoven fabrics using ionizing radiation  

International Nuclear Information System (INIS)

A method is described for producing a resin-bonded nonwoven fabric. The preparation involves forming a fibrous web annealing it and compressing it to provide fiber to fiber contact. A polymerizable binder is applied to the fibrous web which is then treated by ionizing radiation to produce the material. 9 figures, 3 drawing

417

Cytogenetic methods in diagnosis of acute radiation injuries  

International Nuclear Information System (INIS)

The historical development of the use of cytogenetic methods in the diagnosis of acute radiation injuries is the basis for this paper. The use of biochemical analysis and chromosomal studies, and the future role of cytogenetic studiies are related topics discussed

418

Emittance measurements of FEL accelerators using optical transition radiation methods  

International Nuclear Information System (INIS)

Measurements of the emittance of the Boeing FEL accelerator operating at 107 Mev, were performed using optical transition radiation (OTR). The results of the three measurement methods: measurement of beam spot size as a function of magnetic quadrupole focusing strength, two screen beam spot measurements, and beam spot-divergence measurements using a OTR interferometer are compared and shown to be in excellent agreement

419

Methods and procedures for internal radiation dosimetry at ORNL  

International Nuclear Information System (INIS)

Procedures, methods, materials, records, and reports used for accomplishing the personnel, internal radiation monitoring program at Oak Ridge National Laboratory are described for the purpose of documenting what is done now for future reference. This document does not include procedures for nuclear accident dosimetry except insofar as routine techniques may apply also to nuclear accident dosimetry capability

420

Simple method of determining induced 32P activity following burning of sulfur tablets by measuring Cherenkov radiation  

International Nuclear Information System (INIS)

A method is described allowing the detemination of induced beta activity of phosphorus-32 using Cherenkov radiation, following the burning of sulfur tablets in the measuring vesels. A mixture of phosphoric acid and sodium phosphate solutions was used as the medium for the production of Cherenkov radiation. The losses of activity during sulfur tablet burning, the detection efficiency and the minimum detectable activity for which the minimum determinable dose was estimated, were determined. The results obtained by measurement with Cherenkov radiation are compared with other techniques of phosphorus-32 detection. The method was tested at VUPL Bratislava on detectors irradited using a 252Cf fast neutron source. From Caswell's data, the fluence-to-kerma conversin factor was determined for a neutron spectrum calculated by the Monte Carlo method. Tissue kerma was estimated from the neutron fluence corresponding to the appropriate values of saturated activity per 1 sulfur-32 nucleus. (author)

 
 
 
 
421

Solder Joints Detection Method Based on Surface Recovery  

Directory of Open Access Journals (Sweden)

Full Text Available Machine vision has been widely used in various industrial productions. However, the study for solder joints detection is not enough. This paper presents a solder joints detection method based on surface recovery. For a single gray-scale image, using shape-from-shading (SFS technology, the surface of the solder joints is recovered. According to the shape distribution, the quality of solder joints is discriminated. In order to improve the accuracy of recovery for real images, hybrid illumination model is introduced and a reflection-component estimation method based on simulated annealing algorithm is designed. Then recovery process of the algorithm is improved. Compared to other detection methods based on two-dimensional images, this method provides more information about explicit physical meaning and make detailed quantitative analysis for solder joints easier. At the same time, even for defect that is difficult to detect, this method also has important research value.

Jiquan Ma

2010-04-01

422

Radiation-corrected harman method for characterization of thermoelectric materials  

Energy Technology Data Exchange (ETDEWEB)

Thermoelectric materials have received renewed interest in the current search for renewable energy. The Harman method is commonly used to determine thermoelectric properties of materials, but due to parasitic heat losses the accuracy of this method is poor at elevated temperatures. Here, we present a simple and effective approach to correct for radiation loss. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Ao, Xianyu; De Boor, Johannes; Schmidt, Volker [Max Planck Institute of Microstructure Physics, Halle (Germany)

2011-11-15

423

Detection of embedded radiation sources using temporal variation of gamma spectral data.  

Energy Technology Data Exchange (ETDEWEB)

Conventional full spectrum gamma spectroscopic analysis has the objective of quantitative identification of all the isotopes present in a measurement. For low energy resolution detectors, when photopeaks alone are not sufficient for complete isotopic identification, such analysis requires template spectra for all the isotopes present in the measurement. When many isotopes are present it is difficult to make the correct identification and this process often requires many trial solutions by highly skilled spectroscopists. This report investigates the potential of a new analysis method which uses spatial/temporal information from multiple low energy resolution 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 isotopes present. This method is referred to as targeted principal component analysis (TPCA). For radiation portal monitor applications, multiple measurements of gamma spectra are taken at equally spaced time increments as a vehicle passes through the portal and the TPCA method is directly applicable to this type of measurement. In this report we describe the method and investigate its application to the problem of detection of a radioactive localized source that is embedded in a distributed source in the presence of an ambient background. Examples using simulated spectral measurements indicate that this method works very well and has the potential for automated analysis for RPM applications. This method is also expected to work well for isotopic detection in the presence of spectrally and spatially varying backgrounds as a result of vehicle-induced background suppression. Further work is needed to include effects of shielding, to understand detection limits, setting of thresholds, and to estimate false positive probability.

Shokair, Isaac R.

2011-09-01

424

A parameter indication method for signal waveforms from radiation detectors  

International Nuclear Information System (INIS)

Recent developments of fast ADCs have made it possible to analyze output waveforms from radiation detectors directly. The waveforms are converted to large number numerical data. To analyze these data, an appropriate method for waveform processing is needed. An analysis method we propose is a Parameter Indication Method (PIM). Parameters to indicate signal waveforms are defined. A course of waveform analyses is performed with these parameters. With PIM, signal waveforms from a HPGe coaxial detector and a 3He proportional detector were analyzed. For a HPGe detector, a selection of sensitive regions has been tried. Whereas, for 3He detector, the wall effect was greatly suppressed using this method. (author)

425

Detection of ultraviolet radiation using tissue equivalent radiochromic gel materials  

Science.gov (United States)

Ferrous Xylenol-orange Gelatin gel (FXG) is known to be sensitive to ionising radiation such as ? and X-rays. The effect of ionising radiation is to produce an increase in the absorption over a wide region of the visible spectrum, which is proportional to the absorbed dose. This study demonstrates that FXG gel is sensitive to ultraviolet radiation and therefore it could functions as UV detector. Short exposure to UV radiation produces linear increase in absorption measured at 550nm, however high doses of UV cause the ion indicator colour to fad away in a manner proportional to the incident UV energy. Light absorbance increase at the rate of 1.1% per minute of irradiation was monitored. The exposure level at which the detector has linear response is comparable to the natural summer UV radiation. Evaluating the UV ability to pass through tissue equivalent gel materials shows that most of the UV gets absorbed in the first 5mm of the gel materials, which demonstrate the damaging effects of this radiation type on human skin and eyes. It was concluded that FXG gel dosimeter has the potential to offer a simple, passive ultraviolet radiation detector with sensitivity suitable to measure and visualises the natural sunlight UV exposure directly by watching the materials colour changes.

Bero, M. A.; Abukassem, I.

2009-05-01

426

Detection of ultraviolet radiation using tissue equivalent radiochromic gel materials  

Energy Technology Data Exchange (ETDEWEB)

Ferrous Xylenol-orange Gelatin gel (FXG) is known to be sensitive to ionising radiation such as {gamma} and X-rays. The effect of ionising radiation is to produce an increase in the absorption over a wide region of the visible spectrum, which is proportional to the absorbed dose. This study demonstrates that FXG gel is sensitive to ultraviolet radiation and therefore it could functions as UV detector. Short exposure to UV radiation produces linear increase in absorption measured at 550nm, however high doses of UV cause