Spontaneous fission xenon in natural gases

Abstract

In the study of natural gases it is particularly important to be able to distinguish between terrestrial juvenile components and those which are of atmospheric origin. The most positive identification of juvenile components is made from studying the isotopic enrichments of those elements which are produced by naturally occurring nuclear processes. Such results may indicate the presence of components which have never been mixed with the atmosphere. Rather extensive studies have been made by various workers on He^4 and Ar^(40) produced by radioactive decay (ALDRICH and NIER 1948, BOATO, CARERI, and SANTANGELO 1957, WASSERBURG, CZAMANSKE, FAUL and HAYDEN 1957, DAMON and KULP 1958, ZARTMAN, WASSERBURG and REYNOLDS 1961, WASSERBURG, MAZOR, and ZARTMAN 1963). In addition to these decay products, the spontaneous fission of U^(238) also contributes, xenon and krypton as gaseous daughter products. These spontaneous fission (and neutron fission) products have been detected in minerals by several workers (KHLOPIN, GERLING and BARANOVSKYA 1947, 1948, MACNAMARA and THODE 1950, WETHERILL 1953, FLEMING and THODE 1953, GERLING and SHOKOLIVKOV 1959, GERLING, SHOKOLIKOV, and MAKAROCHKIN 1959, YOUNG and THODE 1960). In a recent study by BUTLER, JEFFERY, REYNOLDS and WASSERBURG (1963) spontaneous fission xenon was found both in samples of granite and in two samples of natural gases. More recently CLARKE and THODE (1963) have studied some terrestrial natural gases and found contributions of spontaneous fission xenon.