Spectral Analysis of Radioxenon

Abstract

Monitoring changes in atmospheric radioxenon concentrations is a major tool in the detection of an underground nuclear explosion. Ground-based systems like the Automated Radioxenon Sampler /Analyzer (ARSA), the Swedish Unattended Noble Gas Analyzer (SAUNA) and the Automatic portable radiometer of isotopes Xe (ARIX), can collect and detect several radioxenon isotopes by processing and transferring samples into a high-efficiency beta-gamma coincidence detector. The high-efficiency beta-gamma coincidence detector makes these systems highly sensitive to the radioxenon isotopes 133Xe, 131mXe, 133mXe, and 135Xe. The standard analysis of the 2-dimensional beta-gamma energy spectra uses regions of interest (ROI) to determine the amount of a particular radioxenon isotope present by summing the counts in region. This method relies on the peaks of interest falling within energy limits of the region. Some potential problems inherent in this method are the reliance on stable detector gains and a fixed resolution for each energy peak. In addition, when a high activity sample is measured, there will be more interference among the ROI, in particular within the 133Xe, 133mXe, and 131mXe regions. A solution to some of these problems can be obtained through spectral fitting of the data. Spectral fitting is simply the fitting of the peaks using known functions to determine the number and relative peak positions and widths. By knowing this information it is possible to determine which isotopes are present. The area under each peak can then be used to determine an overall concentration for each isotope. Using the areas of the peaks, several key detector characteristics can be determined: efficiency, energy calibration, energy resolution, and ratios between interfering isotopes (Radon daughters).

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Document Details

Document Type
Technical Report
Publication Date
Sep 01, 2008
Accession Number
ADA516270

Entities

People

  • Brian T. Schrom
  • Charles W. Hubbard
  • James C. Hayes
  • Justin I. Mcintyre
  • Matthew W. Cooper
  • Ted W. Bowyer
  • Tom R. Heimbigner

Organizations

  • Pacific Northwest National Laboratory

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Abstracts
  • Air Force Research Laboratories
  • Algorithms
  • Analyzers
  • Calibration
  • Detection
  • Detectors
  • Efficiency
  • Explosions
  • Gamma Rays
  • Ground Based
  • Measurement
  • Monitoring
  • Nuclear Explosions
  • Spectra
  • Standards
  • X Rays

Fields of Study

  • Physics

Readers

  • Nuclear and Radiation Engineering.
  • Spectroscopy.