Empirical Confirmation of the Critical Level for Zero and Near Zero Background Measurements

Hickman, D P ; Simpson, T

Lawrence Livermore National Laboratory

关键词: Urine;    Lawrence Livermore National Laboratory;    Plutonium-Alpha;    Alpha Spectroscopy;    Radioisotopes;   

DOI  :  10.2172/15006258
RP-ID  :  UCRL-ID-145114
RP-ID  :  W-7405-ENG-48
RP-ID  :  15006258

美国|英语

来源: UNT Digital Library

【 摘 要 】

The alpha spectroscopy system of the Lawrence Livermore National Laboratory, Hazards Control Department evaluates electroplated samples, typically urine and feces, for alpha emitting radionuclides. Most of the samples processed by the alpha spectroscopy system are evaluated for Plutonium-239 (Pu-239), an important radionuclide used in research. This paper evaluates the Pu-239 background response of the Lawrence Livermore National Laboratory Hazards Control Department's alpha spectroscopy system. Background measurements of the alpha spectroscopy system have been studied to determine an appropriate method for establishing the a postori critical level for detection of plutonium alpha activity. Several methods of establishing the 95% confidence interval for over 4,900 background measurements were evaluated. Two methods appear to provide reasonable results so as to assure an appropriate 95% confidence interval. This report provides the results of this evaluation and the comparison of the various methods tested to establish an empirical evaluation of the critical level using a commercially available analysis program.