Download or read book Gamma Ray Detector Optimization for Mobile Detectors Detection at a distance Capability for Locating Lost Or Stolen Nuclear Materials written by and published by . This book was released on 1976 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Energy Research and Development Administration supports a program enabling a rapid response to situations requiring a mobile, detection-at-a-distance capability for locating lost or stolen nuclear materials. For this application, man-portable, vehicular-borne, and airborne detection systems are used. For gamma ray detection, NaI detectors are usually used. Because weight is a serious constraint, many systems employ unshielded detectors. Results of optimization studies to determine a suitable thickness for 12.7 cm diameter NaI detectors that are commonly used in these applications are presented.

Download or read book ERDA Energy Research Abstracts written by United States. Energy Research and Development Administration and published by . This book was released on 1977 with total page 852 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Energy Research Abstracts written by and published by . This book was released on 1977 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.

Download or read book ERDA Energy Research Abstracts written by United States. Energy Research and Development Administration. Technical Information Center and published by . This book was released on 1977 with total page 1680 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bet nkning angaaende Politiets Ordning m v afgiven af den ved kgl Ordre af 23 Oktober 1916 nedsatte Kommission til at forberede en Omordning af de g ldende Regler med Hensyn til Politiets Ordning m v written by and published by . This book was released on 1919 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Remote Detection of Fissile Material written by Anna S. Erickson and published by . This book was released on 2011 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: The need for large-size detectors for long-range active interrogation (Al) detection has generated interest in water-based detector technologies. AI is done using external radiation sources to induce fission and to detect, identify, and characterize special nuclear material (SNM) through the gamma rays and neutrons emitted. Long-range applications require detectors with a large solid angle and an ability to significantly suppress lowenergy background from linear electron accelerators. Water Cherenkov Detectors (WCD) were selected because of their transportability, scalability, and an inherent energy threshold. The main objective of this thesis was to design a large-size WCD capable of detecting gamma rays and to demonstrate particle energy discrimination ability. WCD was modeled in detail using Geant4 for optimization purposes. The experimental detector is composed of an aluminum body with a high efficiency (98.5%) diffuse reflector. Cherenkov photons are detected with six 8" hemispherical Hamamatsu photomultiplier tubes (PMT). PMTs are calibrated using two monoenergetic LEDs. The detector was shown to successfully detect gamma rays of energies above the Cherenkov threshold. The detector was able to discriminate between various sources, such as 60Co and 232Th, even though WCD are known for their poor energy resolution. The detector design and analysis was completed, and it was demonstrated both computationally and experimentally that it is possible to use WCD to detect and characterize gamma rays. One of the accomplishments of this thesis was demonstration of event reconstruction capability of the detector system. A full-detector model was created using Geant4 simulation toolkit. The performance of the detector was predicted using the model and then experimentally verified. The qualitative agreement between the model and the experiment was observed. The event reconstruction was an important part of the detector performance analysis. Post-experimental data processing was done using ROOT.

Download or read book Nuclear Physics And Gamma ray Sources For Nuclear Security And Nonproliferation Proceedings Of The International Symposium written by Takehito Hayakawa and published by World Scientific. This book was released on 2014-10-24 with total page 379 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear nonproliferation is a critical global issue. A key technological challenge to ensuring nuclear nonproliferation and security is the detection of long-lived radioisotopes and fissionable nuclides in a non-destructive manner. This technological challenge requires new methods for detecting relevant nuclides and the development of new quantum-beam sources. For example, one new method that has been proposed and studied is nuclear resonance fluorescence with energy-tunable, monochromatic gamma-rays generated by Compton scattering of laser photons with electrons.The development of new methods requires the help of researchers from a wide range of fields, such as nuclear physics, accelerator physics, laser physics, etc. Furthermore, any new method must be compatible with the requirements of administrators and nuclear-material inspectors.

Download or read book Advanced Nuclear Radiation Detectors written by Ashok K. Batra and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a comprehensive guide to the current state-of-the-art science and technology involved in the analysis and development of gamma-ray nuclear materials for commercial, medical, industrial, military and space applications. It reviews the current and upcoming materials and material-based technologies for gamma-ray detectors, as well as their growth process in various forms, such as single crystals, films, and ceramics. Thoroughly compiled, it is ideal for graduate students, engineers, technicians, scientists and managers. It brings to both novice and advanced readers all the topics required to jump-start investigations on gamma-ray materials and their growth.

Download or read book ERDA Energy Research Abstracts written by United States. Energy Research and Development Administration and published by . This book was released on 1977 with total page 918 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Gamma Ray Background Variability in Mobile Detectors written by Timothy John Aucott and published by . This book was released on 2014 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gamma-ray background radiation significantly reduces detection sensitivity when searching for radioactive sources in the field, such as in wide-area searches for homeland security applications. Mobile detector systems in particular must contend with a variable background that is not necessarily known or even measurable a priori. This work will present measurements of the spatial and temporal variability of the background, with the goal of merging gamma-ray detection, spectroscopy, and imaging with contextual information--a "nuclear street view" of the ubiquitous background radiation. The gamma-ray background originates from a variety of sources, both natural and anthropogenic. The dominant sources in the field are the primordial isotopes potassium-40, uranium-238, and thorium-232, as well as their decay daughters. In addition to the natural background, many artificially-created isotopes are used for industrial or medical purposes, and contamination from fission products can be found in many environments. Regardless of origin, these backgrounds will reduce detection sensitivity by adding both statistical as well as systematic uncertainty. In particular, large detector arrays will be limited by the systematic uncertainty in the background and will suffer from a high rate of false alarms. The goal of this work is to provide a comprehensive characterization of the gamma-ray background and its variability in order to improve detection sensitivity and evaluate the performance of mobile detectors in the field. Large quantities of data are measured in order to study their performance at very low false alarm rates. Two different approaches, spectroscopy and imaging, are compared in a controlled study in the presence of this measured background. Furthermore, there is additional information that can be gained by correlating the gamma-ray data with contextual data streams (such as cameras and global positioning systems) in order to reduce the variability in the background. This is accomplished by making many hours of background measurements with a truck-mounted system, which utilizes high-purity germanium detectors for spectroscopy and sodium iodide detectors for coded aperture imaging. This system also utilizes various peripheral sensors, such as panoramic cameras, laser ranging systems, global positioning systems, and a weather station to provide context for the gamma-ray data. About three hundred hours of data were taken in the San Francisco Bay Area, covering a wide variety of environments that might be encountered in operational scenarios. These measurements were used in a source injection study to evaluate the sensitivity of different algorithms (imaging and spectroscopy) and hardware (sodium iodide and high-purity germanium detectors). These measurements confirm that background distributions in large, mobile detector systems are dominated by systematic, not statistical variations, and both spectroscopy and imaging were found to substantially reduce this variability. Spectroscopy performed better than the coded aperture for the given scintillator array (one square meter of sodium iodide) for a variety of sources and geometries. By modeling the statistical and systematic uncertainties of the background, the data can be sampled to simulate the performance of a detector array of arbitrary size and resolution. With a larger array or lower resolution detectors, however imaging was better able to compensate for background variability.

Download or read book Tableaux anciens et modernes cadres anciens argenterie ancienne written by and published by . This book was released on 1945 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Precision Measurement of Uniformity of Materials by Gamma ray Transmission written by Arthur I. Berman and published by . This book was released on 1951 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book INIS Atomindex written by and published by . This book was released on 1977 with total page 1082 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Identification of Nuclear Materials from Remote Detection of Characteristic Gamma Rays written by L. W. Brasure and published by . This book was released on 1985 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research effort studies the application of Bayes' decision theorem to extending the range of remote identification of nuclear materials. The Finite Element Method was used to develop a radiation transport code which was used to reconstruct a group of three sample sources at distances of 50, 100, 200, 300, 400, and 500 meters. Both the Poisson and multinomial distributions were then used to simulate measured sources in a low count environment at these six ranges. Bayes' theorem was applied to the resulting measured sources to test for positive identification. The results show that a low resolution detector can increase the range of remote detection an average of 100 meters when compared with the method of photopeak identification. Bayes' theorem is unable, however, to identify sources not contained in the library of known sources. Originator supplied keywords include: Gamma Ray Spectra, Bayes' Theorem, Remote Detection, Radioactive Materials.

Download or read book Monte Carlo Simulations of Ultra High Energy Resolution Gamma Detectors for Nuclear Safeguards written by and published by . This book was released on 2009 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultra-high energy resolution superconducting gamma-ray detectors can improve the accuracy of non-destructive analysis for unknown radioactive materials. These detectors offer an order of magnitude improvement in resolution over conventional high purity germanium detectors. The increase in resolution reduces errors from line overlap and allows for the identification of weaker gamma-rays by increasing the magnitude of the peaks above the background. In order to optimize the detector geometry and to understand the spectral response function Geant4, a Monte Carlo simulation package coded in C++, was used to model the detectors. Using a 1 mm3 Sn absorber and a monochromatic gamma source, different absorber geometries were tested. The simulation was expanded to include the Cu block behind the absorber and four layers of shielding required for detector operation at 0.1 K. The energy spectrum was modeled for an Am-241 and a Cs-137 source, including scattering events in the shielding, and the results were compared to experimental data. For both sources the main spectral features such as the photopeak, the Compton continuum, the escape x-rays and the backscatter peak were identified. Finally, the low energy response of a Pu-239 source was modeled to assess the feasibility of Pu-239 detection in spent fuel. This modeling of superconducting detectors can serve as a guide to optimize the configuration in future spectrometer designs.

Download or read book Characterization and Applications of a CdZnTe Based Multimode Imager written by Michelle Galloway and published by . This book was released on 2014 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Detection of electromagnetic radiation in the form of gamma rays provides a means to discover the presence of nuclear sources and the occurrence of highly-energetic events that occur in our terrestrial and astrophysical environment. The highly penetrative nature of gamma rays allows for probing into objects and regions that are obscured at other wavelengths. The detection and imaging of gamma rays relies upon an understanding of the ways in which these high-energy photons interact with matter. The applications of gamma-ray detection and imaging are numerous. Astrophysical observation of gamma rays expands our understanding of the Universe in which we live. Terrestrial detection and imaging of gamma rays enable environmental monitoring of radioactivity. This allows for identification and localization of nuclear materials to prevent illicit trafficking and to ultimately protect against harmful acts. Additionally, terrestrial-based detection is essential, for example, in monitoring the widespread contamination within the Fukushima prefecture in Japan as a result of a nuclear power plant accident. This dissertation focusses on the development and characterization of a gamma-ray detection and imaging instrument and explores its capabilities for the aforementioned applications. The High Efficiency Multimode Imager, HEMI, is a prototype instrument that is based on Cadmium Zinc Telluride (CdZnTe) semiconductor detectors. The detectors are arranged in a two-planar configuration to allow for both Compton and coded-aperture imaging. The front plane consists of active detectors in a random mask pattern to serve simultaneously as a coded mask and a Compton scatter plane, thus providing high detection efficiency. The use of multimode imaging extends the energy range to allow for localization of sources with gamma-ray emissions from tens of keV to a few MeV. HEMI was initially developed as a prototype instrument to demonstrate its capabilities for nuclear threat detection, spectroscopy, and imaging. The 96-detector instrument was developed and fully characterized within the laboratory environment, yielding a system energy resolution of 2.4% FWHM at 662 keV, an angular resolution of 9.5 deg. FWHM at 662 keV in Compton mode, and a 10.6 deg. angular resolution in coded aperture mode. After event cuts, the effective area for Compton imaging of the 662 keV photopeak is 0.1 cm 22. Imaging of point sources in both Compton and coded aperture modes have been demonstrated. The minimum detectable activity of a 137Cs at a 20 m distance with 20 seconds of observation time is estimated to be 0.2 mCi in spectral mode and 20 mCi in Compton imaging mode. These performance parameters fulfilled the requirements of the nuclear security program. Following the Fukushima Dai-ichi Nuclear Power Plant accident of March, 2011, efficient methods to assess levels of radioactive contamination over large areas are needed to aid in clean-up efforts. Although a field study was not initially intended for the HEMI prototype, its portability, low mass, and low power requirements made it a good candidate to test Compton imaging from an aerial platform. The instrument was brought to Japan in August, 2013, allowing for the first test of a Compton imager from a helicopter. The instrument and detectors proved reliable and performed well under high temperature, high humidity, and vibrations. Single-detector hit energy resolutions ranged from 2.5 - 2.8% FWHM at 662 keV. The field testing of the HEMI instrument in Fukushima revealed areas of higher activity of cesium among a diffuse background through aerial-based countrate mapping and through ground measurements. Although the Compton reconstructed events were dominated by random coincidences, preliminary Compton imaging results are promising. A future mission in medium-energy gamma-ray astrophysics would allow for many scientific advancements, e.g., a possible explanation for the excess positron emission from the Galactic Center, a better understanding of nucleosynthesis and explosion mechanisms in Type Ia supernovae, and a look at the physical forces at play in compact objects such as black holes and neutron stars. A next-generation telescope requires good energy resolution, good angular resolution, and high sensitivity in order to achieve these objectives. Large-volume CdZnTe detectors are an attractive candidate for a future instrument because of their good absorption, simple design, and minimal or no cooling requirements. Using the benchmarked HEMI CdZnTe detectors, a Compton telescope with a passive coded mask was designed and simulated with the goal of creating a very sensitive instrument that is capable of high angular resolution. The simulated telescope showed achievable energy resolutions of 1.68% FWHM at 511 keV and 1.11% at 1809 keV, on-axis angular resolutions in Compton mode of 2.63 deg. FWHM at 511 keV and 1.30 deg. FWHM at 1809 keV, and is capable of resolving sources to at least 0.2 deg. at lower energies with the use of the coded mask. An initial assessment of the instrument yields an effective area of 183 cm 2 at 511 keV and an anticipated all-sky sensitivity of 3.6 x 10 −6 photons/cm2/s for a broadened 511 keV source over a 2 year observation time. Additionally, combining a coded mask with a Compton imager to improve point source localization for positron detection has been demonstrated.

Download or read book Nomographs for Use in the Fabrication and Testing of Ge Li Detectors written by Alvin H. Sher and published by . This book was released on 1970 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Six nomographs which can facilitate the fabrication and testing of lithium-drifted germanium gamma-ray detectors (Ge(Li) detectors) have been constructed which relate the following parameters:time, temperature, applied bias, and drifted depth:lithium mobility, crystal resistivity, and oxygen concentration; area, capacitance, and drifted depth for planar Ge(Li) detectors; drifted depth, length, and capacitance for coaxial Ge(Li) detectors; total spectral resolution; system noise, and detector resolution; gamma-ray energy, and effective Fano factor.The use of these nomographs is described and illustrative examples are given.(Author).