Gamma rays from the interaction of 14-MeV neutrons with beryllium

Abstract

The cross section for the Be 9 (n, t')Li 7 *-+L/ + y (0.477 Mev) reaction has been measured in the vicinity of 14 Mev by detecting the gam;ma-rays at scattering angles from 30 to 150 degrees. A time-of-flight technique was used to distinguish the gamma-rays from the high neutron background. The cross section drops_from 20mb at 13.6 Mev to 10mb at 14. 1 Mev and then rises to 30mb at 14.7 Mev.

Measurement of the 477.6-keVγ-ray production cross section following inelastic neutron scattering byLi7

“…Several possibilities for a reference cross section have been considered in [1,2], where the 477.6-keV 1/2 − → 3/2 − g.s. transition in 7 Li was concluded to be one of the best candidates. Factors making this transition favorable include an isotropic γ -ray emission, a negligible internal conversion coefficient, a low inelastic threshold (546 keV), and a fairly smooth energy dependence of the cross section.…”

“…Lithium and beryllium fluorides are also interesting as coolants for molten salt reactor systems, as described in the Technology roadmap for generation IV nuclear energy systems [3]. Additionally, in deuterium-tritium fusion reactors the fuel cycle requires breeding of tritium from 6,7 Li. The interactions between neutrons and lithium affect the tritium breeding ratio, nuclear heating, and radiation damage.…”

“…The interactions between neutrons and lithium affect the tritium breeding ratio, nuclear heating, and radiation damage. Thus good quality nuclear data on neutron-and proton-induced reactions of 6,7 Li are necessary.…”

“…The γ -ray production cross section for the 477.6-keV 1/2 − → 3/2 − g.s. transition in 7 Li following inelastic neutron scattering has been measured from the reaction threshold up to 18 MeV. This cross section is interesting as a possible standard for other γ -ray production cross-section measurements.…”

Remote analysis of surfaces by neutron-gamma-ray inelastic scattering technique

“…For a number of years at this laboratory we have been investigating by various techniques the 7 rays produced by the interaction of 14-Mev neutrons in many pure elements Zenger, 1957, Benveniste, Mitchell, Schrader, andZenger, 1960]. Having accumulated a large body of information concerning spectra and cross sections, plus the techniques of neutron production and 7 detection, we can apply this knowledge in reverse order to the chemical analysis of elements in unknown materials.…”