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Description: Procedures for the routine calibration of gamma-ray scintillation spectrometers and multichannel pulse-height analyzers are presented. A scintillation spectrometer, designed for use of recently developed computer data processing techniques, is described. The performance specifications required of all electronic components in this application, particularly the performance specifications for multi-channel pulse-height analyzers, are treated; and simple tests are described for determining the performance specifications of an analyzer. (auth)
Date: November 1, 1963
Creator: Crouch, D.F. & Heath, R.L.
Partner: UNT Libraries Government Documents Department

CryoFree Final Report

Description: CryoFree, a gamma-ray spectrometer, has been built and successfully tested. This instrument is based on a planar germanium semiconductor detector and is optimized for high-resolution spectroscopy in the range of a 30 keV to a few hundred keV to detect U and Pu. The spectrometer is cooled with a mechanical cryocooler that obviates the need for liquid cryogen. Furthermore, the instrument is battery powered. The combination of mechanical cooling and battery operation allows high-resolution spectroscopy in a highly-portable field instrument. A description of the instrument along with its performance is given.
Date: November 7, 2006
Creator: Burks, M
Partner: UNT Libraries Government Documents Department

Delineating the major KREEP-bearing terranes on the moon with global measurements of absolute thorium abundances

Description: The Lunar Prospector (LP) Gamma-Ray Spectrometer (GRS) has been used to map the global composition of thorium on the lunar surface. Previous LP results of relative thorium abundances demonstrated that thorium is highly concentrated in and around the nearside western maria and less so in the South Pole Aitken (SPA) basin. Using new detector modeling results and a larger data set, the authors present here a global map of absolute thorium abundances on a 2{degree} by 2{degree} equal-area pixel scale. Because thorium is a tracer of KREEP-rich material, these data provide fundamental information regarding the locations and importance of terranes that are rich in KREEP bearing materials.
Date: March 1, 1999
Creator: Lawrence, D.J.; Feldman, W.C.; Barraclough, B.L.; Elphic, R.C.; Prettyman, T.H.; Binder, A.B. et al.
Partner: UNT Libraries Government Documents Department


Description: >An examination was made to observe the extent and location of corrosion, crud deposits, and defects in components of the PWR pnimary fluid system and its auxiliaries. A gamma spectrum of the four-inch line upstream from the two pressurizer self-actuated relief valves showed the presence of Mn/sup 54/ and Co/sup 60/. From the gamma spectrum and the gross gamma activity, the Co/sup 60/ was found to be 5.03 x 10/sup 3/ dpm/mg or about 70 per cert of the gross gnmma activity. (J.R.D.)
Date: January 20, 1961
Partner: UNT Libraries Government Documents Department

Environmental Tests of the Flight GLAST LAT Tracker Towers

Description: The Gamma-ray Large Area Space telescope (GLAST) is a gamma-ray satellite scheduled for launch in 2008. Before the assembly of the Tracker subsystem of the Large Area Telescope (LAT) science instrument of GLAST, every component (tray) and module (tower) has been subjected to extensive ground testing required to ensure successful launch and on-orbit operation. This paper describes the sequence and results of the environmental tests performed on an engineering model and all the flight hardware of the GLAST LAT Tracker. Environmental tests include vibration testing, thermal cycles and thermal-vacuum cycles of every tray and tower as well as the verification of their electrical performance.
Date: March 12, 2008
Creator: Bagagli, R.; Baldini, L.; Bellazzini, R.; Barbiellini, G.; Belli, F.; Borden, T. et al.
Partner: UNT Libraries Government Documents Department

Development of Room-temperature CdMnTe Gamma-ray Detectors

Description: CdMnTe materials have wide bandgap, high resistivity, fair electron-transport properties, and good compositional uniformity. All these features make CdMnTe a good candidate for low cost, high-resolution room-temperature gamma-ray detector. Using several techniques available at BNL, we are characterizing CdMnTe as a material for gamma-ray detectors. The consequent improvements in growth, fabrication, and manufacturing techniques for CdMnTe potentially yield a suitable material for sensing devices with lower production costs. Success of this research has the possibility of generating high impact to nuclear nonproliferation with the goal of offering inexpensive highly sensitive gamma spectrometers.
Date: June 17, 2008
Creator: Bolotnikov, A.
Partner: UNT Libraries Government Documents Department

Determination of Thorium in Rock Samples by Gamma Spectrometry

Description: An investigation was made of the feasibility of measuring thorium in rock samples by use of scintillation spectrometry facilities available in the ORNL Analytical Chemistry Division. Results of measurement of eleven samples indicate that the method is usable and that agreement with chemical analysis is reasonable. (auth)
Date: June 1, 1960
Creator: Reynolds, S. A.
Partner: UNT Libraries Government Documents Department

Initial recommendations for restricting gamma-ray spectrometry measurements of radionuclides for on-site inspections

Description: The US paper �Radionuclide Sampling, Sample Handling and Analytical Laboratory Equipment for Comprehensive Test Ban Treaty On-Site Inspections,� CTBT/PC/V/OSI/WSII/PR/29 identified the radionuclides of interest to an OS1 as <sup>144</sup>Ce, <sup>147</sup>Nd, <sup>141</sup>Ce, <sup>149</sup>Ba<sup>140</sup>La), <sup>95</sup> Zr(<sup>95</sup>Nb), <sup>131m</sup>Xe, <sup>133m</sup>Xe, <sup>133g</sup>Xe, <sup>135g</sup>Xe, and <sup>37</sup>Ar. All of these nuclides (except <sup>37</sup>Ar) can be measured via some form of conventional or coincidence-based gamma-ray spectrometry. The non-gaseous radionuclides [<sup>144</sup>Ce, <sup>147</sup>Nd, <sup>141</sup>Ce, <sup>140</sup>Ba(<sup>140</sup>La), and <sup>95</sup>Zr(<sup>95</sup>Nb)] can be measured via conventional high-resolution gamma-ray spectrometry using a shielded, high-purity germanium (HPGe) detector. The gaseous radionuclides <sup>131m</sup>Xe, <sup>133m</sup>Xe, <sup>133g</sup>Xe, and <sup>135g</sup>Xe are best measured (after separation from their homologous elements) via a gamma & beta/electron coincidence technique such as that described in CTBT/WGB/TL-11/5 which could utilize either a HPGe or low-resolution (NaI(TI)) gamma-ray spectrometer to detect the gamma-ray/x-ray and a plastic scintillator to detect the beta particle/electron from the decay of the various Xe isotopes. The US paper CTBT/PC/V/IOSI/WSII/PR/29 (and other papers) identified a need to limit the information that can be extracted from high-resolution gamma-ray spectra to ensure that only information relevant to an OSI is accessible. The term �blinding� has been used to describe the need to limit the information available to the Inspection Team from the high-resolution gamma-ray measurement. A better term is �measurement restriction�; the need for restricting the information is particularly relevant to conventional high-resolution gamma-ray spectrometry measurements, but not to the gamma & beta/electron coincidence-type measurements envisioned for Xe isotopes because the separation process for these radionuclides will likely eliminate any other observables. The purpose of this paper is to define functional requirements for restricting measurements via conventional high- resolution gamma-ray spectrometry systems to ensure that only the nuclides of interest to an OSI can be identified and quantified. Options discussed below include 1) acquisition and analysis of the entire high-resolution gamma-ray spectrum combined with ...
Date: November 6, 1998
Creator: Buckley, W. F.; Kreek, S. A. & Wild, J. F.
Partner: UNT Libraries Government Documents Department

Lunar prospector measurements of the distribution of incompatible elements gadolinium, samarium and thorium

Description: Lunar Prospector neutron spectrometer (NS) and gamma ray spectrometer (GRS) observations have been used to map out the distribution of incompatible elements on the lunar surface. Specifically, the GRS data provide maps of the distribution of thorium and potassium while the NS data provide information on the distribution of iron and titanium, and the rare earth elements gadolinium and samarium. Using results of analysis of Celementine spectral reflectance (CSR) data, the Fe- and Ti-contributions to the NS data can be removed, leaving primarily rare earth element contributions from Gd and Sm. The Th and K maps correlate with the inferred Gd and Sm maps (r {approximately} 0.93), but there are regions of significant disagreement. One of these is in the KREEP-rich circum-Imbrium ring. No clear explanation has emerged for this disagreement, though Th, K, Gd and Sm have differing degrees of incompatibility. These results clearly are important to discussions of the geochemistry of the Procellarum-Imbrium Th-rich Terrane and the South-Pole-Aitken Terrane.
Date: April 1, 1999
Creator: Elphic, R.C.; Lawrence, D.J.; Feldman, W.C.; Barraclough, B.L.; Maurice, S.; Binder, A.B. et al.
Partner: UNT Libraries Government Documents Department

A field-deployable gamma-ray spectrometer utilizing high pressure xenon

Description: Most nuclear materials in the nuclear energy, safeguards, arms control, and nonproliferation regimes emit gamma rays with a unique signature. Currently, two categories of spectrometers are available to evaluate these materials: (1) Semiconductors, with excellent energy resolution, which operate at cryogenic temperatures. (2) Scintillation detectors, which function at ambient temperature, but with poor energy resolution. A detector which functions for extended periods in a range of environments, with an energy resolution superior to that of a scintillation spectrometer, would have evident utility. Recently, in the research community, such a device has evolved, an ionization chamber utilizing xenon gas at very high pressure (60 atm). Its energy resolution, typically, is 20 keV for the 661 keV gamma ray of {sup 137}Cs. With high xenon density and its high atomic number (Z=54), and superior energy resolution, its sensitivity is comparable to that of a scintillator.
Date: May 1, 1997
Creator: Smith, G.C.; Mahler, G.J.; Yu, Bo; Kane, W.R. & Lemley, J.R.
Partner: UNT Libraries Government Documents Department

Gamma-ray pulse height spectrum analysis on systems with multiple Ge detectors using a spectrum summing

Description: A technique has been developed at the Idaho National Engineering Laboratory to sum high resolution gamma-ray pulse spectra from systems with multiple Ge detectors. Lockheed Martin Idaho Technologies Company operates a multi-detector spectrometer configuration at the Stored Waste Examination Pilot Plant facility which is used to characterize the radio nuclide contents in waste drums destined for shipment to Waste Isolation Pilot Plant. This summing technique was developed to increase the sensitivity of the system, reduce the count times required to properly quantify the radionuclides and provide a more consistent methodology for combining data collected from multiple detectors. In spectrometer systems with multiple detectors looking at non homogenous waste forms it is often difficult to combine individual spectrum analysis results from each detector to obtain a meaningful result for the total waste container. This is particularly true when the counting statistics in each individual spectrum are poor. The spectrum summing technique adds the spectra collected by each detector into a single spectrum which has better counting statistics than each individual spectrum. A normal spectral analysis program can then be used to analyze the sum spectrum to obtain radio nuclide values which have smaller errors and do not have to be further manipulated to obtain results for the total waste container.
Date: May 1, 1997
Creator: Killian, E.W.
Partner: UNT Libraries Government Documents Department

A portable gamma-ray spectrometer using compressed xenon

Description: An ionization chamber using compressed xenon has been designed and built for gamma-ray spectrometry. The device is based on signal measurement from a parallel plate detector, with the gas enclosure constructed specifically for packaging into a portable instrument; thus, appropriate engineering practices comprises two small containers that can be setup for operation in just a few minutes. Its sensitivity is 100 keV to over 1 MeV, with a resolution at 662 keV of 2.5% FWHM for uniform irradiation, and 2% FWHM for collimated irradiation, comparable to the best ever with compressed xenon. It also exhibits greater specificity that most scintillators, such as NaI. The device is insensitive to neutron damage and has a low power requirement.
Date: October 1, 1997
Creator: Mahler, G.J.; Yu, B.; Smith, G.C.; Kane, W.R. & Lemley, J.R.
Partner: UNT Libraries Government Documents Department

Mapping the elemental composition of the moon: Current results of the Lunar Prospector gamma ray spectrometer

Description: One of the instruments on board the recently launched Lunar Prospector spacecraft is a Gamma-Ray Spectrometer (GRS) designed to map the surface elemental composition of the Moon. Specifically, the objectives of the GRS are to map abundances of Fe, Ti, U, Th, K, Si, O and if possible Mg, Al, and Ca. The GRS consists of a bismuth germanate (BGO) crystal placed within a well shaped borated plastic scintillator anti-coincidence (ACS) shield. Events triggering only the BGO are labeled as accepted events; events triggering both the BGO and ACS are labeled as rejected events. BGO spectra for both accepted and rejected events are telemetered to the ground for later analysis. Results of the study are given.
Date: December 1, 1998
Creator: Lawrence, D.J.; Feldman, W.C.; Barraclough, B.L.; Elphic, R.C.; Binder, A.B. & Maurice, S.
Partner: UNT Libraries Government Documents Department

A small diameter, flexible, all attitude, self-contained germanium spectrometer. Operator`s manual

Description: The end of the Cold War has brought about tremendous changes in the nuclear complex of the Department of Energy. One of the many changes has been the shutdown or decommissioning of many facilities that performed nuclear work. One of the steps in the process of decommissioning a facility involves the decontamination or removal of drain lines or pipes that may have carried radioactive materials at one time. The removal of all these pipes and drain lines to a nuclear disposal facility could be quite costly. It was suggested by Pacific Northwest National Laboratory (PNNL) that a germanium spectrometer could be built that could fit through straight pipes with a diameter as small as 5.08 cm (2 inches) and pass through curved pipes with a diameter as small as 7.6 cm (3 inches) such as that of a 3-inch p-trap in a drain line. The germanium spectrometer could then be used to simultaneously determine all gamma-ray emitting radionuclides in or surrounding the pipe. By showing the absence of any gamma-ray emitting radionuclides, the pipes could then be reused in place or disposed of as non-radioactive material, thus saving significantly in disposal costs. A germanium spectrometer system has been designed by PNNL and fabricated by Princeton Gamma Tech (PGT) that consists of three segments, each 4.84 cm in diameter and about 10 cm in length. Flexible stainless steel bellows were used to connect the segments. Segment 1 is a small liquid nitrogen reservoir. The reservoir is filled with a sponge-like material which enables the detector to be used in any orientation. A Stirling cycle refrigerator is under development which can replace the liquid nitrogen reservoir to provide continuous cooling and operation.
Date: May 1, 1997
Creator: Bordzindki, R.L.; Lepel, E.A.; Reeves, J.H. & Kohli, R.
Partner: UNT Libraries Government Documents Department

High Pressure XENON Gamma-Ray Spectrometers for Field Use

Description: This project explored a new concept for high-pressure xenon ionization chambers by replacing the Frisch grid with coplanar grid electrodes similar to those used in wide bandgap semiconductor gamma-ray spectrometers. This work is the first attempt to apply the coplanar grid anode design in a gas ionization chamber in order to achieve to improved energy resolution. Three prototype detectors, two cylindrical and one parallel plate configurations, were built and tested. While the detectors did not demonstrate energy resolutions as good as other high pressure xenon gamma-ray spectrometers, the results demonstrated that the concept of single polarity charge sending using coplanar grid electrodes will work in a gas detector.
Date: February 16, 2004
Creator: Wehe, David K.; He, Zong & Knoll, Glenn K.
Partner: UNT Libraries Government Documents Department


Description: A feasibility study was conducted on the application of activation analysis to forensic chemistry. Test portions of automobile paint finish, soot, and soil samples were irradiated in the ORNL Graphite Reactor and the induced gamma radioactivity of each specimen measured with a gamma scintillation spectrometer. Spectral decay curves of the radionuclides in the various specimens classified the materials as to origin. This nondestructive technique is particularly suitable for the analysis of evidence samples that must be maintained in its as-is'' state. (auth)
Date: September 11, 1962
Creator: Bate, L.C.; Pro, M.J. & Leddicotte, G.W.
Partner: UNT Libraries Government Documents Department