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Nuclear structure studies with the inelastic neutron scattering rection and gamma-ray detection

Description: The (<i>n</i>, <i>n</i>ยด(gamma)) reaction has been used at the University of Kentucky accelerator facility to examine the detailed structure of a number of nuclei. The advantages of this method are reviewed, and recent developments are described. Examples of unique nuclear structure studies that have been carried out with this method are presented.
Date: December 10, 1998
Creator: Garrett, P. E.; Warr, N. & Yates, S. W.
Partner: UNT Libraries Government Documents Department

W-026, acceptance test report gamma energy assay (GEA) system A(submittal {number_sign}39.8) C3

Description: This test procedure is designed to test all of the functions of the GEA system at the WRAP facility at Hanford, Washington. The procedure is designed to be executed in the sequence given, starting with: * verification of components and labeling * verification or entry of all of the setup parameters * performing the calibrations (energy, efficiency, transmission, and reference peak) * performing the measurements in local mode * performing the measurements in remote mode * confirming the message formats * utility operations (LN2 fill, archiving, password maintenance) The system is designed to be operated in a remote mode in which all commands are received over a network, and the results are returned over the same network. A manual mode is provided for the setup and calibration operations, and for maintenance functions. The system is designed to start up in remote mode. The user can go to local mode when at the keyboard by selecting Exit on the screen shown during remote mode. A user logon screen, requiring 2 username and password, limits access to local mode.
Date: January 28, 1997
Creator: Watson, T.L., Westinghouse Hanford Co., Richland, WA
Partner: UNT Libraries Government Documents Department

DMSP satellite detections of gamma-ray bursts

Description: Gamma-ray burst detectors are aboard six U. S. Air Force defense Meteorological Satellite Program (DMSP) spacecraft, two of which are currently in use. Their 800-km altitude orbits give a field of view to 117 degrees from the zenith. A great many bursts have been detected, usually in coincidence with detections by GRO or other satellites such as PVO or ULYSSES. The directions of the sources can be determined with considerable accuracy from such correlated observations, even when GRO/BATSE with its directional capabilities is not involved. Thus these DMSP data, especially in conjunction with other observations, should be helpful in trying to understand the true nature of gamma-ray bursts. 8 refs., 5 figs.
Date: December 31, 1995
Creator: Terrell, J.; Lee, P. & Klebesadel, R.W.
Partner: UNT Libraries Government Documents Department

Semiconductor Radiation Detectors with Frisch Collars and Collimators for Gamma Ray Spectroscopy and Imaging

Description: To study CdZnTe as a high energy resolution gamma ray detector with a novel new design, and to build a detector array from the new detector design
Date: December 4, 2006
Creator: McGregor, Douglas; Kargar, Alireza; Harrison, Mark; Brooks, Adam; McNei, Walter; Lowell, Rans et al.
Partner: UNT Libraries Government Documents Department


Description: A gamma-radiation telemetering system was utilized to measure fall-out levels at the Ncvada Test Site. Two methods of signal transmission were used: directcoupled field lines for on-site installations and commercial telephone lines for areas out to 330 miles. Graphic and tabular data cover on-site and off- site residual gamma-radiation dose rate measurements taken as a function of time after selected events. (auth)
Date: November 1, 1958
Creator: Sigoloff, S.C. & Borella, H.M.
Partner: UNT Libraries Government Documents Department

Proposed Emulsion Experiment Search for Short Lived Particles at High Energies

Description: It is proposed to conduct an experiment at the National Accelerator Laboratory concerned with the search for new particles having lifetimes between 10{sup -17} and 10{sup -12} second. The experiment will be conducted with an emulsion chamber arranqement and will explore for particles with lifetimes too short to be observed directly with other instruments. Two sidelines of the experiment will be concerned with an improved measurement of the lifetime of the neutral pion and the search for gamma ray bundles arising from higher mass resonances which cannot decay by pion emission.
Date: April 19, 1972
Creator: Kotzer, Peter; Lord, J.J. & U., /Washinton
Partner: UNT Libraries Government Documents Department

Xenon Gamma Detector Project Support

Description: This project provided funding of $48,500 for part of one year to support the development of compressed xenon spectrometers at BNL. This report describes upgrades that were made to the existing detector system electronics during that period, as well as subsequent testing with check sources and Special Nuclear Materials. Previous testing of the equipment extended only up to the energy of 1.3 MeV, and did not include a spectrum of Pu-239. The new electronics allowed one-button activation of the high voltage ramp that was previously controlled by manual adjustments. Mechanical relays of the charging circuit were replaced by a tera-ohm resistor chain and an optical switch. The preamplifier and shaping amplifier were replaced by more modern custom designs. We found that the xenon purity had not been degraded since the chamber was filled 10 years earlier. The resulting spectra showed significantly better resolution than sodium iodide spectra, and could be analyzed quite effectively by methods using peak area templates.
Date: April 1, 2008
Creator: Vanier, P. E. & Forman, L.
Partner: UNT Libraries Government Documents Department

Using NAI detectors for tomographic gamma scanning

Description: The authors examined two approaches for using NaI detectors to perform transmission corrections used in the tomographic gamma scanner (TGS) and segmented gamma scanner (SGS) nondestructive assay methods. They found that a material-basis-set (MBS) fit using empirical logarithmic response spectra is quite accurate. Because this is a gross count technique, it gives sensitivities (for equal numbers of detectors) that are roughly ten times better than those obtained using Germanium detectors. The authors also found that simple continuum subtraction can be used in MBS fits using the energy-group-analysis technique only when the Pu transmission is greater than 10%. Both approaches for using NaI detectors require a knowledge of the Pu (or other) isotopics to obtain full accuracy.
Date: March 1, 1997
Creator: Estep, R.J. & Melton, S.
Partner: UNT Libraries Government Documents Department

Coplanar-grid detector with single-electrode readout

Description: The coplanar-grid technique provides substantial spectral performance improvement over that of conventional detector designs and electronics when applied to gamma-ray detectors based on compound semiconductors. The technique realizes this improvement by measuring the difference between the induced charge signals from two interdigitated coplanar-grid electrodes. By adjusting the relative gain between the two grid signals prior to subtraction, the difference signal can be made less sensitive to the poor carrier transport properties of the detector material and thus improve the spectral response of the detector. In this paper, the authors discuss a variation of the coplanar-grid method in which the signal from only one grid electrode is read out. The signal response is optimized by changing the relative areas of the two grid electrodes and the bias applied across the detector. In this scheme, only one preamplifier is needed and signal subtraction is not necessary. This eliminates the electronic noise contribution from the additional preamplifier used in the normal coplanar-grid implementation, and conventional single-amplifier detector electronics can be used. Experimental results using CdZnTe detectors are presented.
Date: April 1, 1997
Creator: Amman, M. & Luke, P.N.
Partner: UNT Libraries Government Documents Department

A tunable crystal diffraction telescope for the International Space Station

Description: Even though technically innovative, a tunable crystal diffraction telescope for use in nuclear astrophysics has become feasible today. The focusing gamma-ray telescope the authors intended to propose for the space station consists of a tunable crystal diffraction lens, focusing gamma-rays onto a small array of Germanium detectors perched on an extendible boom. While the weight of such an instrument is less than 500 kg, it features an angular resolution of 15 inches, an energy resolution of 2 keV and a 3 {sigma} sensitivity of a few times 10{sup {minus}7} photons{center_dot}s{sup {minus}1}{center_dot}cm{sup {minus}2} (10{sup 6} sec observation) for any individual narrow line at energies between 200--1,300 keV. This experience would greatly profit from the continuous presence of man on the station. Besides of the infrastructure for maintenance and servicing of the various innovative techniques used for the first time in space, the available extra-vehicular robotics will facilitate deployment of the required boom structure.
Date: February 1, 1997
Creator: Ballmoos, P. von; Kohnle, A.; Olive, J.F.; Vedrenne, G.; Smither, R.K.; Fernandez, P.B. et al.
Partner: UNT Libraries Government Documents Department

Gamma ray scanner systems for nondestructive assay of heterogeneous waste barrels

Description: Traditional gamma safeguards measurements have usually been performed using a segmented gamma scanning (SGS) system. The accuracy of this technique relies on the assumption that the sample matrix and the activity are both uniform for a segment. Waste barrels are often highly heterogeneous, span a wide range of composition and matrix type. The primary sources of error are all directly or indirectly related to a non-uniform measurement response associated with unknown radioactive source spatial distribution and heterogeneity of the matrix. These errors can be significantly reduced by some imaging techniques that measure exact spatial locations of sources and attenuation maps. In this paper we describe a joint R&D effort between the Lawrence Livermore National Laboratory (LLNL) and the Institute of Nuclear Techniques (INT) of the Technical University, Budapest, to compare results obtained by two different gamma-ray nondestructive assay (NDA) systems used for imaging waste barrels. The basic principles are the same, but the approaches are different. Key factors to judge the adequacy of a method are the detection limit and the accuracy. Test drums representing waste to be measured are used to determine basic parameters of these techniques.
Date: March 25, 1997
Creator: Martz, H.E.; Decman, B.J.; Roberson, G.P. & Levai, F.
Partner: UNT Libraries Government Documents Department


Description: This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project consisted of a series of balloon flights to collect high-time-resolution x-ray and electric-field-change measurements in thunderstorms in order to validate the existence of the runaway air-breakdown mechanism during lightning and/or sprite production. The runaway air-breakdown mechanism is currently the leading theory to account for unexplained balloon and aircraft-based measurements of x-ray enhancements associated with sprites. Balloon-borne gamma-ray and electric-field-change instruments were launched into a daytime summer thunderstorm. A greater than three-fold increase in the gamma-ray flux was observed as the balloon descended through a thunderstorm anvil where a strong electric field was present. These observations suggest that gamma-ray production in thunderstorms may not be as uncommon as previously believed.
Date: August 1, 2000
Creator: EACK, K.; SUSZCYNSKY, D. & AL, ET
Partner: UNT Libraries Government Documents Department

Snowpack snow water equivalent measurement using the attenuation of cosmic gamma radiation

Description: Incoming, background cosmic radiation constantly fluxes through the earth`s atmosphere. The high energy gamma portion of this radiation penetrates many terrestrial objects, including the winter snowpack. The attenuation of this radiation is exponentially related to the mass of the medium through which it penetrates. For the past three winters, a device measuring cosmic gamma radiation--and its attenuation through snow--has been installed at the Central Sierra Snow Laboratory, near Donner Pass, California. This gamma sensor, measuring energy levels between 5 and 15 MeV, has proved to be an accurate, reliable, non-invasive, non-mechanical instrument with which to measure the total snow water equivalent of a snowpack. This paper analyzes three winters` worth of data and discusses the physics and practical application of the sensor for the collection of snow water equivalent data from a remote location.
Date: May 1, 1998
Creator: Osterhuber, R.; Fehrke, F. & Condreva, K.
Partner: UNT Libraries Government Documents Department

A continuous watch of the northern sky above 40 TeV with the CYGNUS array

Description: This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The aim of the project has been to continuously monitor the northern sky for transient high-energy gamma-ray emission from astrophysical sources. Potential objects of such emission include gamma-ray bursts and flares from active galaxies. At the start of this project, the CYGNUS extensive air shower array was used for the monitoring; CYGNUS has an energy threshold of {approximately}40 TeV. In August, 1996, the CYGNUS data-acquisition computer suffered a fatal hardware problem so data-taking with the array ended. The Milagrito detector, which is much more sensitive than CYGNUS, started taking data in February 1997 and has continued the sky monitoring. The authors are presently honing reconstruction algorithms for Milagrito. When this is complete, the data taken since February will be analyzed for transient emission.
Date: November 1, 1998
Creator: Haines, T.J.; Miller, R. & Sinnis, C.
Partner: UNT Libraries Government Documents Department

A method to improve spectral resolution in planar semiconductor gamma-ray detectors

Description: This paper describes an empirically derived algorithm to compensate for charge trapping in CdTe, CdZnTe, and other planar semiconductor detectors. The method is demonstrated to be an improvement over available systems and application to experimental data is shown.
Date: May 1, 1995
Creator: Keele, B.D.; Addleman, R.S. & Troyer, G.L.
Partner: UNT Libraries Government Documents Department