FRAM Version 6.1’s Bias

Technical Report · Tue Sep 03 04:00:00 EDT 2019

DOI:https://doi.org/10.2172/1561047· OSTI ID:1561047

Vo, Duc Ta ^[1]

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1. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

The Fixed-Energy Response-Function Analysis with Multiple Efficiency (FRAM) code was developed at Los Alamos National Laboratory to measure the gamma-ray spectrometry of the isotopic composition of plutonium, uranium, and other actinides. For FRAM version 4 and earlier, the reported uncertainties of the results come from the propagation of the statistics in the peak areas only. No systematic error components are included in the reported uncertainties. We did several studies with FRAM v.4 and found that FRAM’s statistical precision can be reasonably represented by its reported uncertainties. FRAM’s biases or systematic uncertainties can come from a variety of sources and can be difficult to determine. For FRAM version 5, we carefully examined the FRAM analytical results of both the archival plutonium data and the data specifically acquired for the isotopic uncertainty analysis project and found the relationship between the bias and other parameters. We then worked out the equations representing the biases of the measured isotopes from each measurement using internal spectral parameters, such as peak resolution and shape, region of analysis, and burnup (for plutonium) or enrichment (for uranium). The resulting biases were included in the reported uncertainties of FRAM v.5. For the upcoming FRAM version 6.1, we are doing the same study that we did for FRAM v.5. The resulting biases will be included in its reported uncertainties.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: 89233218CNA000001
• OSTI ID: 1561047
• Report Number(s): LA-UR--19-28874
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
97 MATHEMATICS AND COMPUTING
isotopic analysis
FRAM
uranium
plutonium