Measurement of the 242gAm (T1/2=16.02 hour) fission cross section

Abstract

There was performed a cycle of 242g Am fission characteristics measurements with the use of IRT-MEPhI reactor. The 242g Am isotope was produced in the course of irradiating 241 Am targets in the experimental channel with the density of neutron flux ≈2 · 10 13 1/(cm 2 ·s). Then, with no isolation of americium-242 from the irradiated targets the time dependencies of induced fission fragments yield from the targets were measured. Moreover the irradiated americium targets undertook irradiation in another channel of IRT reactor with the density of thermal neutron flux ≈5.6 · 10 10 1/(cm 2 ·s). The fission fragments were registered with the aid of dielectric track detectors. In each time dependence of fission fragments an exponent with T1/2 = 16.02hour is available; the cross section of 242g Am fission by thermal and resonance neutrons was determined by the intensity of induced fissions with the given half-life. The quantity of 242g Am nuclei in each of irradiated targets was determined basing on accumulation of 242 Cm, daughter product of 242g Am decay. Based on the experimental results for the 242g Am nuclide, the evaluations of both the fission cross section by thermal neutrons and the fission resonance integral were obtained.