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Title: Improved Background Corrections for Uranium Holdup Measurements

Abstract

In the original Generalized Geometry Holdup (GGH) model, all holdup deposits were modeled as points, lines, and areas[1, 5]. Two improvements[4] were recently made to the GGH model and are currently in use at the Y-12 National Security Complex. These two improvements are the finite-source correction CF{sub g} and the self-attenuation correction. The finite-source correction corrects the average detector response for the width of point and line geometries which in effect, converts points and lines into areas. The result of a holdup measurement of an area deposit is a density-thickness which is converted to mass by multiplying it by the area of the deposit. From the measured density-thickness, the true density-thickness can be calculated by correcting for the material self-attenuation. Therefore the self-attenuation correction is applied to finite point and line deposits as well as areas. This report demonstrates that the finite-source and self-attenuation corrections also provide a means to better separate the gamma rays emitted by the material from the gamma rays emitted by background sources for an improved background correction. Currently, the measured background radiation is attenuated for equipment walls in the case of area deposits but not for line and point sources. The measured background radiation ismore » not corrected for attenuation by the uranium material. For all of these cases, the background is overestimated which causes a negative bias in the measurement. The finite-source correction and the self-attenuation correction will allow the correction of the measured background radiation for both the equipment attenuation and material attenuation for area sources as well as point and line sources.« less

Authors:
; ;
Publication Date:
Research Org.:
Oak Ridge Y-12 Plant, Oak Ridge, TN (US)
Sponsoring Org.:
USDOE Office of Defense Programs (DP) (US)
OSTI Identifier:
833931
Report Number(s):
Y/DK-2107
TRN: US200430%%2008
DOE Contract Number:  
AC05-00OR22800
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 21 Jun 2004
Country of Publication:
United States
Language:
English
Subject:
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE; ATTENUATION; BACKGROUND RADIATION; GEOMETRY; NATIONAL SECURITY; POINT SOURCES; URANIUM

Citation Formats

Oberer, R B, Gunn, C A, and Chiang, L G. Improved Background Corrections for Uranium Holdup Measurements. United States: N. p., 2004. Web. doi:10.2172/833931.
Oberer, R B, Gunn, C A, & Chiang, L G. Improved Background Corrections for Uranium Holdup Measurements. United States. doi:10.2172/833931.
Oberer, R B, Gunn, C A, and Chiang, L G. Mon . "Improved Background Corrections for Uranium Holdup Measurements". United States. doi:10.2172/833931. https://www.osti.gov/servlets/purl/833931.
@article{osti_833931,
title = {Improved Background Corrections for Uranium Holdup Measurements},
author = {Oberer, R B and Gunn, C A and Chiang, L G},
abstractNote = {In the original Generalized Geometry Holdup (GGH) model, all holdup deposits were modeled as points, lines, and areas[1, 5]. Two improvements[4] were recently made to the GGH model and are currently in use at the Y-12 National Security Complex. These two improvements are the finite-source correction CF{sub g} and the self-attenuation correction. The finite-source correction corrects the average detector response for the width of point and line geometries which in effect, converts points and lines into areas. The result of a holdup measurement of an area deposit is a density-thickness which is converted to mass by multiplying it by the area of the deposit. From the measured density-thickness, the true density-thickness can be calculated by correcting for the material self-attenuation. Therefore the self-attenuation correction is applied to finite point and line deposits as well as areas. This report demonstrates that the finite-source and self-attenuation corrections also provide a means to better separate the gamma rays emitted by the material from the gamma rays emitted by background sources for an improved background correction. Currently, the measured background radiation is attenuated for equipment walls in the case of area deposits but not for line and point sources. The measured background radiation is not corrected for attenuation by the uranium material. For all of these cases, the background is overestimated which causes a negative bias in the measurement. The finite-source correction and the self-attenuation correction will allow the correction of the measured background radiation for both the equipment attenuation and material attenuation for area sources as well as point and line sources.},
doi = {10.2172/833931},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2004},
month = {6}
}