Akademik Veri Yönetim Sistemi
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, cilt.413, sa.1, ss.74-82, 1998 (SCI-Expanded)
For the direct gamma-ray spectrometric measurements of uranium concentrations in the samples, the use of 1001 keV peak of Pa-234m, second daughter of U-238 is emphasized. This "clean" peak is well resolved bg HPGe detectors and gives accurate indication of uranium concentration in the samples without any self-absorption correction. The 1001 keV peak of Pa-234m the U-238 chain is selected because it does not include any contribution from any other gamma emissions and does not have any interference with other peaks in the high-energy region even if the samples contain high amounts of thorium. The activity of Pa-234m is determined by calibrating a HpGe detector with uranium standards. The measurement of 1001 keV gamma-ray emission from Pa-234m by high-resolution gamma-ray spectrometry provides the basis for a reliable determination of U-238 in the samples. The results obtained from the 63.3 keV peak of Th-234 and those of the 1001 keV peak from Pa-234m in the U-238 chain for the uranium standards are compared with the certified values of the same samples. The results obtained from the measurements of 1001 keV peak from Pa-234m agreed to within 2-5% with the certified activity values of U-238 in the samples with uranium content ranging from 0.014 to 1.02 wt%. The results indicate that the uranium concentrations in the samples can be determined to within 5% error by about 14 h counting in a HpGe detector system. (C) 1998 Elsevier Science B.V. All rights reserved.