Accession Number : AD0612991

Title :   A KRYPTON-81 HALF-LIFE DETERMINATION USING A MASS SEPARATOR,

Corporate Author : ATOMIC ENERGY OF CANADA LTD CHALK RIVER (ONTARIO)

Personal Author(s) : Eastwood,T. A. ; Brown,F. ; Crocker,I. H.

Report Date : 19 MAR 1964

Pagination or Media Count : 9

Abstract : The half-life of 81Kr was determined with aid of a mass separator equipped with a current integrator. In each experiment a natural krypton sample was irradiated with neutrons to produce 81Kr. After determining the 81-82 atom ratio with a conventional mass spectrometer, the sample was processed in the mass separator, the mass 81 beam being collected in aluminium foil while the mass 82 fraction was collected simultaneously in the Faraday cup of the current integrator. The number of atoms of 81Kr collected in the aluminium foil was calculated from the 81-82 atom ratio and the integrated current of 82Kr. The disintegration rate of these atoms was determined by counting the bromine K X-rays produced in the electroncapture decay of 81Kr using a NaI scintillation spectrometer and thus the half-life was deduced. Tests using natural krypton mixed with 11 y 85Kr showed that = 3% accuracy can be achieved with the current integrator. The average of six determinations of the half-life was 213,000 y with an estimated experimental error = 5%. However, when the uncertainty in the 81r decay energy (250=90keV) was included the error was increased, giving T1/2(81Kr) = (213,000=16,000 or-26,000)y, a value that agrees with the only previous measurement and is more accurate. (Author)

Descriptors :   (*HALF LIFE, KRYPTON), (*KRYPTON, HALF LIFE), MASS SPECTROSCOPY, ELECTRON CAPTURE, ISOTOPE SEPARATION

Distribution Statement : APPROVED FOR PUBLIC RELEASE