Measurement of the 230U half-life

The U-230 half-life was determined by measuring the decay curve of U-230 sources by various nuclear detection techniques: alpha-particle counting at a defined small solid angle; 4 pi alpha+beta counting with a windowless CsI sandwich spectrometer, a liquid scintillation counter and a pressurised proportional counter; gamma-ray spectrometry with a HPGe detector and nearly-2 pi alpha-particle counting with an ion-implanted silicon detector. Depending on the technique, the decay was followed for 100-200 d, which is 5-10 times the U-230 half-life. The measurement results of the various techniques were in good mutual agreement. The mean value, T-1/2(U-230)=20.23 (2) d, is lower than the literature value which is based on one measurement in 1948 and resulted in a half-life value of 20.8 d without statement of uncertainty. A correction for the ingrowth of the long-lived Pb-210 and its daughter products may have been overlooked in the past. (C) 2012 Elsevier Ltd. All rights reserved.