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Title: Spectral gamma-ray log data analysis for NTS borehole ER-20-6 {number_sign}1

Technical Report ·
DOI:https://doi.org/10.2172/481521· OSTI ID:481521

In the characterization work underway at the Nevada Test Site Underground Test Area, the logging contractor, Western Atlas, has been asked to identify five artificial nuclides based on their gamma-ray signatures. Those nuclides are {sup 60}Co (cobalt-60), {sup 106}Ru (ruthenium-106), {sup 125}Sb (antimony-125), {sup 134}Cs (cesium-134) and {sup 137}Cs (cesium-137). The Western Atlas spectral gamma-ray tool uses a 2 in. by 12 in. CsI(Na) (sodium-doped cesium iodide) scintillation detector. Cesium iodide has lower energy resolution than the better known sodium iodide scintillation material but is more rugged and is also more efficient, giving higher count rates especially at higher energies and potentially better counting statistics. Detected gamma rays are divided into 256 energy bins using a pulse-height analyzer in the tool, and the data are transmitted up the logging cable in digital form. Western Atlas personnel perform an energy calibration before and after each logging run using a calibration gamma-ray source. Atlas also performs a running adjustment of the spectral energy scale during the office post-processing based on the positions of known peaks in the naturally occurring spectral components, this is important and will be discussed.

Research Organization:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE Assistant Secretary for Human Resources and Administration, Washington, DC (United States)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
481521
Report Number(s):
LA-UR-97-1087; ON: DE97007447; TRN: AHC29712%%62
Resource Relation:
Other Information: PBD: [1997]
Country of Publication:
United States
Language:
English