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Title: Design and performance of a new high accuracy combined small sample neutron/gamma detector

Conference ·
OSTI ID:10180455
 [1]; ; ;  [2];  [3]; ;  [4];  [5]
  1. Los Alamos National Lab., NM (United States)
  2. Jomar Systems, Inc., Los Alamos, NM (United States)
  3. Commission of the European Communities, Luxembourg (Luxembourg)
  4. Commission of the European Communities, Karlsruhe (Germany, F.R.). European Inst. for Transuranium Elements
  5. Commission of the European Communities, Geel (Belgium)

This paper describes the design of an optimized combined neutron and gamma detector installed around a measurement well protruding from the floor of a glove box. The objective of this design was to achieve an overall accuracy for the plutonium element concentration in gram-sized samples of plutonium oxide powder approaching the {approximately}0.1--0.2% accuracies routinely achieved by inspectors` chemical analysis. The efficiency of the clam-shell neutron detector was increased and the flat response zone extended in axial and radial directions. The sample holder introduced from within the glove box was designed to form the upper reflector, while two graphite half-shells fitted around the thin neck of the high-resolution LEGE detector replaced the lower plug. The Institute for Reference Materials and Measurements (IRMM) in Geel prepared special plutonium oxide test samples whose plutonium concentration was determined to better than 0.05%. During a three week initial performance test in July 1992 at ITU Karlsruhe and in long term tests, it was established that the target accuracy can be achieved provided sufficient care is taken to assure the reproducibility of sample bottling and sample positioning. The paper presents and discusses the results of all test measurements.

Research Organization:
Los Alamos National Lab., NM (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States); Commission of the European Communities, Brussels (Belgium)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
10180455
Report Number(s):
LA-UR-93-2670; CONF-930749-26; ON: DE93018463; TRN: 93:019919
Resource Relation:
Conference: 34. annual meeting of the Institute of Nuclear Materials Management,Scottsdale, AZ (United States),18-21 Jul 1993; Other Information: PBD: 1993
Country of Publication:
United States
Language:
English