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Mechanically Cooled Large-Volume Germanium Detector Systems for Neclear Explosion Monitoring DOENA27323-2

Description: Compact maintenance free mechanical cooling systems are being developed to operate large volume high-resolution gamma-ray detectors for field applications. To accomplish this we are utilizing a newly available generation of Stirling-cycle mechanical coolers to operate the very largest volume germanium detectors with no maintenance. The user will be able to leave these systems unplugged on the shelf until needed. The maintenance-free operating lifetime of these detector systems will exceed 5 years. Three important factors affect the operation of mechanically cooled germanium detectors: temperature, vacuum, and vibration. These factors will be studied in the laboratory at the most fundamental levels to insure a solid understanding of the physical limitations each factor places on a practical mechanically cooled germanium detector system. Using this knowledge, mechanically cooled germanium detector prototype systems will be designed and fabricated.
Date: October 30, 2006
Creator: Hull, E.L.
Partner: UNT Libraries Government Documents Department

Mechanically Cooled Large-Volume Germanium Detector Systems for Nuclear Explosion Monitoring DOENA27323-1

Description: Compact maintenance free mechanical cooling systems are being developed to operate large volume germanium detectors for field applications. To accomplish this we are utilizing a newly available generation of Stirling-cycle mechanical coolers to operate the very largest volume germanium detectors with no maintenance. The user will be able to leave these systems unplugged on the shelf until needed. The flip of a switch will bring a system to life in ~ 1 hour for measurements. The maintenance-free operating lifetime of these detector systems will exceed 5 years. These features are necessary for remote long-duration liquid-nitrogen free deployment of large-volume germanium gamma-ray detector systems for Nuclear Explosion Monitoring. The Radionuclide Aerosol Sampler/Analyzer (RASA) will greatly benefit from the availability of such detectors by eliminating the need for liquid nitrogen at RASA sites while still allowing the very largest available germanium detectors to be reliably utilized.
Date: July 28, 2006
Creator: Hull, E.L.
Partner: UNT Libraries Government Documents Department

Emergency petroleum conservation: a review and analysis of selected measures

Description: ORNL was asked by the Economic Regulatory Administration to (1) collect, screen, and recommend a limited number of emergency measures that might conserve petroleum in residential and commercial buildings and in commercial transportation and (2) provide a detailed analysis of the energy savings and the economic and environmental impacts associated with restricting the hours of operation of commercial buildings. A total of 41 emergency measures were identified that might conserve petroleum, and these were reduced to a list of five that seemed most promising. Analysis of the measure to restrict hours of operation for commercial buildings shows that it might save 4 to 6% of annual commercial building energy use. The type of fuel conserved would vary widely from region to region, and appreciable negative economic impacts would result from implementing the measure.
Date: January 1, 1980
Creator: Boercker, F.D.; Balasubramaniam, M.; Hull, E.; Savadelis, J. & Valentini, J.J.
Partner: UNT Libraries Government Documents Department

Imaging Performance of the Si/Ge Hybrid Compton Imager

Description: The point spread function (PSF) of a fully-instrumented silicon/germanium Compton telescope has been measured as a function of energy and angle. Overall, the resolution ranged from 3{sup o} to 4{sup o} FWHM over most of the energy range and field of view. The various contributions to the resolution have been quantified. These contributions include the energy uncertainty and position uncertainty of the detector; source energy; Doppler broadening; and the 1/r broadening characteristic of Compton back-projection. Furthermore, a distortion of the PSF is observed for sources imaged off-axis from the detector. These contributions are discussed and compared to theory and simulations.
Date: November 10, 2005
Creator: Burks, M; Chivers, D; Cork, C; Cunningham, M; Fabris, L; Gunter, D et al.
Partner: UNT Libraries Government Documents Department

First-Generation Hybrid Compact Compton Imager

Description: At Lawrence Livermore National Laboratory, we are pursuing the development of a gamma-ray imaging system using the Compton effect. We have built our first generation hybrid Compton imaging system, and we have conducted initial calibration and image measurements using this system. In this paper, we present the details of the hybrid Compton imaging system and initial calibration and image measurements.
Date: November 7, 2005
Creator: Cunningham, M; Burks, M; Chivers, D; Cork, C; Fabris, L; Gunter, D et al.
Partner: UNT Libraries Government Documents Department