Download or read book A Multi Layer Phoswich Radioxenon Detection System written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Laboratory radioactive sources were used to characterize the phoswich detector. The CaF2 scintillator has a low light-yield and slow decay time, thus produces very small signals due to low-energy gamma rays or X-rays. Therefore, detection of 30 keV X-rays (from the xenon radioisotopes) using this layer and discriminating its very small signals from electronic noise was a challenging task. Several solutions were considered and experimentally evaluated. We found that the best solution would be extending the fast triangular filter from 10 taps to 30 taps. This will extend the peaking time of this filter from 25 nsec to 75 nsec. The digital filter is implemented in FPGA on our DPP2.0 and is used to trigger the detection system. Functionality of the new filter in capturing and discriminating 30 keV X-rays was confirmed by using a 133Ba gamma-ray source. Development of the DPP GUI software has continued with the addition of two new panels to display histograms of beta/gamma and beta/x-ray coincidence events. This includes coincidence events from a single channel, as well as two-channel, coincidence event. A pileup rejection algorithm has been implemented in the FPGA code, and controls to adjust its sensitivity have been added to the GUI. Work has begun on a new prototype system to develop a USB host interface between the PC and the FPGA to end reliance on Opal Kelly prototyping boards; the hardware for this system has been completely assembled, and the PC-side software is currently in development.

Download or read book A Multi Layer Phoswich Radioxenon Detection System Reporting Period 07 written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: During this quarter, the detector manufacturer (Saint-Gobain) delivered one side of the prototype two-channel phoswich detector (XEPHWICH). Once received, our Digital Pulse Processor (DPP1, 12-bit/100 MHz) was employed to capture and digitally process phoswich pulses from laboratory radioactive sources. Our previous pulse shape discrimination algorithm was modified by utilizing three trapezoidal digital filters. This algorithm provides a two-dimensional plot in which the pulse shapes of interest are classified and then can be well identified. The preliminary experimental results will be presented at the 2007 Informal Xenon Monitoring Workshop. The DPP2 (two-channel, 12-bit/ 250 MHz Digital Pulse Processor) is at the prototyping stage. The analog sections have been designed, prototyped and tested. A 6-layer Printed Circuit Board (PCB) was designed, ordered and delivered. The board components were ordered and are now being assembled and examined for proper functionality. In addition, the related FPGA hardware description code (using VHDL) is under development and simulation. Additionally, our researchers have been studying materials regarding wavelet transforms for incorporation into the project. Wavelet transform is an interesting tool for signal processing; one use for our purpose would be to de-noise the detector signal and to express the signal in a few coefficients for signal compression and increased speed. Light capture efficiency modeling and analysis was performed on the XEPHWICH design. Increased understanding of the modeling software was obtained by the discovery of a bug and successful workaround techniques with the DETECT2000 software. Further modeling and plot generation experience was had by the continued use of CERN's ROOT and GEANT4 software packages. Simulations have been performed to compare the output of points versus planes in light capture efficiency. An additional simulation was made with a runtime that was an order-of-magnitude greater than previous simulations, to confirm convergence of the solutions provided by our software methods. We have initiated our investigation into the radon signature expected in our XEPHWICH system. We intend to utilize this signature to confirm earth movement, in the event of an underground nuclear explosion, by continuously monitoring radon levels and noting increases in radon concentration in conjunction with increased levels of radioxenons. The research group is also designing and constructing a fission chamber to be used for the collection of radioxenon gases following neutron bombardment of HEU in the Oregon State University TRIGA reactor. To this point, we have completed milling the aluminum housing and have modeled fission product nuclide production associated with the fissioning of HEU. Additionally, the students have been busy compiling the appropriate information in preparation for irradiation approvals. Using beta spectra of three initial nuclides collected on the prototype phoswich detector, spectral identification by a preliminary neural network was compared to that of solvers of a linear system of equations. Pre-processing in areas such as smoothing and endpoint identification is also being investigated as a means of improving spectral identification.

Download or read book A Multi Layer Phoswich Radioxenon Detection System 7th Qtr Report Reporting Period 10 01 07 12 31 07 written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Description of activities conducted this report period: (1) Electronics Development--To improve the overall performance of the two-channel digital pulse processor (DPP2), the PCB has been redesigned and the new printed board is now under assembly. The system is enhanced with two new fast ADCs from Analog Devices (AD9230-250), each with a sampling rate of 250 MHz and a resolution of 12 bits. The data bus uses a high performance Low Voltage Differential Signaling (LVDS) standard. The offset and gain of each channel are separately controlled digitally by the GUI software. (2) GUI Software Development--A GUI is being developed using the Python programming language. All functions from the preceding MATLAB code have been re-implemented including basic waveform readout, pulse shape discrimination, and plotting of energy spectra. In addition, the GUI can be used to control sampling runs based on the number of pulses captured, either in real or live time. Calibration coefficients and pulse shape discrimination boundaries can be changed on the fly so that the detector may be characterized experimentally. Plots generated by the GUI can be exported as graphic data. At present, the software has only been tested using one channel, pending availability of the new DPP board (DPP2). However, the functions have been written to allow easy expansion to two channels. (3) Light Collection Modeling--The XEPHWICH design has been modeled to determine its light capture efficiency. Research in the 7th quarter includes additional simulations representing significant increase in data resolution, well over an order of magnitude greater than previous simulations. The final data set represents approximately 11 billion visible photons divided equally among 110 thousand data points. A laboratory experiment is being designed and executed to experimentally determine light capture efficiency as a function of position within the scintillators. (4) Radioxenon Fission Source--We have designed and constructed a fission chamber to be used for the collection of radioxenon gases following neutron bombardment of HEU in the Oregon State University TRIGA reactor. The aluminum housing and all vacuum fittings have been assembled, awaiting an HEU transfer from PNNL. Students have worked closely with PNNL and OSU Radiation Safety personnel to facilitate transfer of the HEU. The OSU TRIGA Reactor Operations Committee has approved the experiment. (5) Spectral [beta] Recognition--Spectral identification by a neural network developed in our laboratory was compared to that of solvers of a linear system of equations. Data indicate that our neural network is capable of identifying three beta emission sources (14C, 36Cl, and 99Tc) simultaneously with reliability to within 3%.

Download or read book Preliminary Experiments with a Triple Layer Phoswich Detector for Radioxenon Detection written by and published by . This book was released on 2008 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: The International Monitoring System (IMS) employs radiation detectors to monitor atmospheric or underground nuclear weapons tests. These detectors should be able to detect ultra low concentrations of xenon radioisotopes in the atmosphere. Exploiting the fact that the most interesting xenon radioisotopes emit a beta or conversion electron (CE) in coincidence with an X-ray or gamma-ray, these detectors have been designed and optimized to record coincidence events from the radioxenon isotopes. The IMS currently uses detection systems in which beta/CE and X-ray/gamma-ray are measured in separate detectors. Although the ARSA system is able to detect very low concentrations of radioxenon, its complexity makes the beta and gamma-ray energy calibration very difficult. Phoswich technology, accompanied by digital signal processing of photomultiplier tube (PMT) pulses, can simplify radioxenon detection. If well designed, like other current sensitive radioxenon detectors, a phoswich detector is also capable of detecting beta/gamma coincidence events using digital-pulse-shape analysis. We have designed a two-channel triple-layer phoswich detector for radioxenon detection. Each phoswich detector consists of three scintillation layers: a thin plastic (1.5mm) scintillator for detection of beta and CE, a CaF2 layer (2mm) for X-ray detection and a NaI layer (25.4mm) for gamma-ray measurement. A two-channel FPGA-based Digital Pulse Processor, DPP2.0, (250 MHz, 12 bits) has been designed and constructed for capturing and transferring valid phoswich pulses to the PC. A graphical user interface (GUI) also has been developed to control the DPP2.0, digitally analyze phoswich pulses, and reconstruct the 2-D beta/gamma coincidence spectra. In this paper, our digital pulse shape discrimination technique, the DPP2.0, and the GUI are introduced. At the end, our preliminary measurements with the prototypic phoswich detector are discussed.

Download or read book A Two Channel Phoswich Detector for Dual and Triple Coincidence Measurements of Radioxenon Isotopes written by and published by . This book was released on 2007 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: As part of the Comprehensive Nuclear Test Ban Treaty, the International Monitoring System (IMS) has been established for monitoring xenon radioisotopes in the atmosphere to detect atmospheric or underground nuclear explosions. Experimental results from the Automated Radioxenon Sampler/Analyzer (ARSA) system, developed at Pacific Northwest National Laboratory, show that the system is capable of detecting very low concentrations of the fission product radioxenon isotopes (133)Xe, (133m)Xe, (131m)Xe and (135)Xe. To build a more practical radioxenon detection system as sensitive as the ARSA system but with reduced cost, size, power consumption and complexity, several detection systems have been developed or are currently under development. It has been shown (McIntyre et al. 2004) that triple coincidence measurements of beta, conversion electons (CE) and x-ray from the radioxenon gas provides a significant reduction of Compton scatter interference in the 30-keV line and therefore much lower (2-3 orders of magnitude) concentrations of (133)Xe can be detected even with a high radon background. The triple coincidence measurement eliminates the need for additional separation columns and traps (required for removing the background radon) and allows for reduced passive shielding as well, thus reducing the size and power consumption of the system. In this paper, a two-channel phoswich detector is introduced and studied. The detector consists of a thin hollow disk (with 2 mm thickness and 76.2 mm diameter) as the xenon gas cell, surrounded by two identical planar triple-layer phoswich detectors. This design provides a solid angle of about 3.4 pi for the gas cell, close to that of the ARSA system (tilde 3.5 pi). The planar shape of the detectors has several important advantages, among which are the reduced cost due to its simplicity, and because it has a minimum non-uniformity in light collection efficiency, will not unreasonably degrade the beta or gamma energy resolution.

Download or read book Development of a COTS Radioxenon Detector System Using Phoswich Detectors and Pulse Shape Analysis written by and published by . This book was released on 2008 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several of the radioxenon detection systems developed for the International Monitoring System use beta/gamma coincidence detection to achieve high sensitivity. These systems use an arrangement of separate beta and gamma detectors to detect beta/gamma coincidence events characteristic of the different radioxenon isotopes. While very sensitive to small amounts of radioxenon, they also require careful calibration and gain matching of several detectors and photomultiplier tubes. An alternative approach is the use of a single phoswich detector in which beta-gamma coincidences are detected by pulse shape analysis (PSA). We previously reported on prototype phoswich well detectors, consisting of a fast plastic scintillator (absorbing betas) optically coupled to a slower CsI(Tl) scintillator (absorbing gammas). These detectors require only a single photomultiplier tube and an electronics readout channel. Beta/gamma coincidences create characteristic "fast/slow" signals that can easily be distinguished from "slow only" or "fast only" non-coincident interactions. We describe the development of a commercial off-the-shelf (COTS) radioxenon detector system based on such phoswich detectors. The PSA functions were implemented using the digital signal processor in a set of commercial readout electronics that is also compatible with ARSA and SAUNA detectors. These functions detect coincidences in real time and accumulate 2D histograms in on-board memory. The acquisition and the PSA functions can also be integrated into larger-scale acquisition and control software. Several phoswich detectors have been characterized for energy resolution, separation of coincidence events in 2D beta/gamma energy histograms, and detection efficiency. A test pulser module has been developed to support monitoring and testing of the electronics for state of health during operation. The phoswich detector, readout electronics, and software are now available as a COTS product package.

Download or read book Prototyping a Triple layer Phoswich Detection System written by Christopher L. Duncan and published by . This book was released on 2011 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multi-layer optically coupled scintillation based radiation detectors, known as phoswich detectors, have rapidly evolved in recent years. During the same time, digital signal processing has improved radiation discrimination accuracy and enhanced reliability, while reducing complexity and size of traditional analog signal processing methods. A new generation of high-speed radiation detectors that can measure mixed radiation fields has been developed by coupling these advancements. A prototype of one of the first commercially available phoswich detection systems has been analyzed to determine operational characteristics. The phoswich detector was analyzed using a variety of radioactive sources across a battery of tests compiled from the literature, Federal government regulations, and end-users specifications. It was found that the phoswich detection system operates equally well in beta particle, gamma-ray, and combined radiation fields. Testing at 5 centimeters demonstrated the phoswich detector's gamma-ray full-energy-peak intrinsic efficiency to range from 0.64 to 3.25 percent, full-energy-peak resolution from 6.29 (1332 keV) to 12.07 (356 keV) percent, and detectable energy range from 30 keV to 2754 keV. Similar testing for beta particles demonstrated an intrinsic efficiency of up to 58 percent. The system did exhibit saturation in radiation fields above 0.008 uCi when used with MATLAB. The phoswich detection system demonstrated that it is quite capable of accurately measuring the type and energy of radiation present in combined beta particle and gamma-ray radiation fields.

Download or read book Comparison of the Phoswich and ARSA type Detectors for Radioxenon Detection written by Rebecca Morgan Ward and published by . This book was released on 2010 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Comprehensive Nuclear Test Ban Treaty verification regime mandates atmospheric monitoring for the four radioxenon isotopes that are produced in high abundance in a nuclear explosion: [superscript 131m]Xe, [superscript 133m]Xe, [superscript 133g]Xe, and [superscript 135g]Xe. This mandate has driven the development of improved xenon detectors, including a phoswich detector, which has potential to replace the ARSA detector in the International Monitoring System. In this experiment, the four relevant radioxenon isotopes were produced through neutron activation and the phoswich detector was used to attain spectra from the gas. Spectral characteristics and resolution of the phoswich spectra were compared to an ARSA-type [beta]-[gamma] coincidence detector to perform an overall evaluation of the phoswich detector. The results indicated that spectral characteristics and resolutions for the phoswich were comparable to the ARSA-type detector, with slightly improved beta detection. As an additional test of the new detector's capabilities, a tailored spectrum designed to mimic a nuclear explosion signature was produced and analyzed with the detector.

Download or read book An Investigation of the Light Capture Properties of the XEPHWICH a Phoswich Radiation Detection System written by Sean E. Jones and published by . This book was released on 2009 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: The XEPHWICH system is a phoswich type (multiple scintillator) radiation detector designed to detect several radioxenon isotopes with the goal of identifying covert nuclear explosions. The XEPHWICH system is designed with the sole purpose of replacing the Automated Radio-xenon Sampler/Analyzer (ARSA) in the United Nation's (UN) Comprehensive Test Ban Treaty's (CTBT) International Monitoring System (IMS). This study consists of two stages, computer simulation and laboratory experiment. The use of DETECT2000, a Monte-Carlo optical simulator, was the method by which optical performance and potential improvements to the XEPHWICH design were investigated. The laboratory experiment conducted in this study validated the modeling methods used in the study and investigated the effects of light capture efficiency on XEPHWICH system output. The experiment consisted of exposing the NaI(Tl) layer of the XEPHWICH to a lead collimated Cs-137 beam at varying locations, and comparing the differential energy spectra observed. The simulation work resulted in design considerations for improving the optical performance of the XEPHWICH. Additionally, through simulation, the optical performance of the XEPHWICH was characterized and can be compared to competing scintillator designs. The experimental observations included expected and unexpected effects that light capture properties had on the system signal. Of particular importance, the experimental results supported the modeling method applied, and demonstrated that an increase in expected light capture efficiency was associated with better energy resolution for a full energy peak in a differential pulse height spectrum.

Download or read book Real time Radioxenon Measurement Using a Compton suppressed Well type Phoswich Detector for Nuclear Explosion Monitoring written by Bemnet Alemayehu and published by . This book was released on 2013 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radioxenon detection is a technique used to monitor nuclear explosion and verify the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Because of an ultra-low concentration of radioxenon at radioxenon monitoring stations, radioxenon detection systems must have high sensitivity. This sensitivity is measured in terms of detector's minimum detectable concentration (MDC). It is required that radioxenon monitoring systems should have a MDC of less than or equal to 1 mBq/m3 for 133Xe. A Well-type Actively Shielded Phoswich Detector (WASPD) for radioxenon detection was designed and assembled at the Radiation Detection and Dosimetry lab at Oregon State University. The active shielding mechanism is integrated into the phoswich detector to improve the MDC of the radioxenon by reducing unwanted background events. Anode pulses were processed using a user programmable digital pulse processor. All digital processing functions were implemented in a FPGA device in real-time. The detector was characterized for different radioxenon isotopes. MDC calculation of the detector showed that the results are close or below 1 mBq/m3 for all radioxenon isotopes.

Download or read book Gamma Ray Imaging written by Junwei Du and published by Springer Nature. This book was released on 2023-09-12 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book will provide readers with a good overview of some of the most recent advances in the field of detector technology for gamma-ray imaging, especially as it pertains to new applications. There will be a good mixture of general chapters in both technology and applications in medical imaging and industrial testing. The book will have an in-depth review of the research topics from world-leading specialists in the field. The conversion of the gamma-ray signal into analog/digital value will be covered in some chapters. Some would also provide a review of CMOS chips for gamma-ray image sensors.

Download or read book Measurement and Detection of Radiation written by Nicholas Tsoulfanidis and published by Hemisphere Pub. This book was released on 1983 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt: Assuming a basic knowledge of calculus, differential equations and some atomic physics, this classic bestseller enables students to select the proper detector, analyze the results of counting experiments, and perform radiation measurements following proper health physics procedures. Examples and problems in each chapter ensure that students understand the concepts presented. The book cover long-range alpha detector LRAD, pure geranium detectors, magnetic and electrostatic spectrometers, position-sensitive detectors, the LSL-M2 unfolding code, compensated ion chambers, self-powered neutron detectors, new protection guides, and exposure limits. A solutions manual is available for qualifying instructors.

Download or read book Handbook of Radioactivity Analysis written by Michael F. L'Annunziata and published by Academic Press. This book was released on 2020-03-07 with total page 1076 pages. Available in PDF, EPUB and Kindle. Book excerpt: Handbook of Radioactivity Analysis: Radiation Physics and Detectors, Volume One, and Radioanalytical Applications, Volume Two, Fourth Edition, constitute an authoritative reference on the principles, practical techniques and procedures for the accurate measurement of radioactivity - everything from the very low levels encountered in the environment, to higher levels measured in radioisotope research, clinical laboratories, biological sciences, radionuclide standardization, nuclear medicine, nuclear power, and fuel cycle facilities, and in the implementation of nuclear forensic analysis and nuclear safeguards. It includes sample preparation techniques for all types of matrices found in the environment, including soil, water, air, plant matter and animal tissue, and surface swipes.Users will find the latest advances in the applications of radioactivity analysis across various fields, including environmental monitoring, radiochemical standardization, high-resolution beta imaging, automated radiochemical separation, nuclear forensics, and more. - Spans two volumes, Radiation Physics and Detectors and Radioanalytical Applications - Includes a new chapter on the analysis of environmental radionuclides - Provides the latest advances in the applications of liquid and solid scintillation analysis, alpha- and gamma spectrometry, mass spectrometric analysis, Cherenkov counting, flow-cell radionuclide analysis, radionuclide standardization, aerosol analysis, high-resolution beta imaging techniques, analytical techniques in nuclear forensics, and nuclear safeguards - Describes the timesaving techniques of computer-controlled automatic separation and activity analysis of radionuclides - Provides an extensive table of the radiation characteristics of most radionuclides of interest for the radioanalytical chemist

Download or read book Neutron Personnel Dosimetry written by Robert B. Schwartz and published by . This book was released on 1987 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Monitoring a Comprehensive Test Ban Treaty written by Eystein S. Husebye and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 843 pages. Available in PDF, EPUB and Kindle. Book excerpt: An international treaty banning the testing of any nuclear device in any environment - a comprehensive test ban treaty (CTBT) - has been on the political agenda for nearly 40 years. Objections to a CTBT have been political, technical, or a combination of both. However, the possibilities seem better after the end of the Cold War. In the prevailing, cooperative disarmament climate a CTBT appears likely to be approved by most countries in 1996. Hence the great current interest in monitoring technologies and capabilities. Such issues are comprehensively addressed here, a preamble being devoted to the political developments and setbacks over the past 40 years. Since seismic means are considered the dominant monitoring element, they are explored in detail. Contributions cover network deployments, advanced signal processing, wave propagation in heterogeneous media, and seismic source representations, and a variety of techniques for source classification (including neural networks). Complementary monitoring techniques, such as hydroacoustics, radionuclides and infrasound, are also summarised. The IAEA operation for monitoring compliance with the Non-Proliferation Treaty is also presented. The book also includes eyewitness accounts of the Soviet 50 Mt megabomb development and test, as well as the efforts made by the state to monitor the nuclear test programmes of the western powers. Includes some 33 articles written by distinguished scientists active in CTBT monitoring research for decades.

Download or read book Nuclear Principles in Engineering written by Tatjana Jevremovic and published by Springer Science & Business Media. This book was released on 2009-04-21 with total page 558 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear engineering plays an important role in various industrial, health care, and energy processes. Modern physics has generated its fundamental principles. A growing number of students and practicing engineers need updated material to access the technical language and content of nuclear principles. "Nuclear Principles in Engineering, Second Edition" is written for students, engineers, physicians and scientists who need up-to-date information in basic nuclear concepts and calculation methods using numerous examples and illustrative computer application areas. This new edition features a modern graphical interpretation of the phenomena described in the book fused with the results from research and new applications of nuclear engineering, including but not limited to nuclear engineering, power engineering, homeland security, health physics, radiation treatment and imaging, radiation shielding systems, aerospace and propulsion engineering, and power production propulsion.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: