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Abstract  

The Intercomparison Studies Program (ISP) at the Oak Ridge National Laboratory (ORNL, Oak Ridge, TN, USA) provides natural-matrix urine quality-assurance/quality-control (QA/QC) samples to radiobioassay analysis laboratories. In 2003, a single laboratory (Los Alamos National Laboratory LANL, Los Alamos NM USA) requested a change in the test-samples provided previously by the ISP. The change was requested to evaluate measurement performance for analyses conducted using thermal-ionization mass spectrometry (TIMS). Radionuclides included 239Pu at two activity levels (75–150 μBq·sample−1 and 1200–1600 μBq·sample−1) and 238Pu (3700–7400 μBq·sample−1). In addition, 240Pu was added to the samples so that the 239+240Pu specific activity was 3700–7400 μBq·sample−1. In this paper, the results of testing during the period May, 2003 through September, 2005 are presented and discussed.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
K. Inn
,
E. Hall
,
J. Woodward
,
B. Stewart
,
R. Pollanen
,
L. Selvig
,
S. Turner
,
I. Outola
,
S. Nour
,
H. Kurosaki
,
J. LaRosa
,
M. Schultz
,
Z. Lin
,
Z. Yu
, and
C. McMahon

Abstract  

Recoil ions from alpha-particle emission can contaminate surface-barrier detection systems. This contamination results in increased measurement uncertainty, and may require the replacement of expensive detectors. Disposable thin Collodion films are easily prepared and effectively retard the recoil ions when either directly applied to the surface of alpha-sources or as catcher foils between the source and the detector. The thin films are particularly effective for relatively low-level sources, but can sustain structural damage when exposed to high levels of recoil ions (tens of thousands per second) over extended periods of time.

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