Energy spectra for protons emitted in the reaction Ca-nat(n, xp) at 94 MeV

TL;DR

This study measures proton emission spectra from calcium when bombarded with 94 MeV neutrons, providing data to evaluate nuclear reaction models and improve understanding of light-ion production.

Contribution

First experimental measurement of proton spectra from Ca at 94 MeV neutron energy, with detailed analysis and comparison to TALYS nuclear reaction code predictions.

Findings

TALYS overestimates compound nucleus contributions.

TALYS underestimates pre-equilibrium emissions.

Proton spectra obtained down to 2.5 MeV energy.

Abstract

The MEDLEY setup based at The Svedberg Laboratory (TSL), Uppsala, Sweden has previously been used to measure double-differential cross-sections for elastic nd scattering, as well as light ion production reactions for various nuclei in the interaction with neutrons around 95 MeV. When moved to the new beam line, the first experimental campaign was on light-ion production from Ca at 94 MeV in February 2005. These data sets have been analyzed for proton production in forward and backward angles. The Delta E - Delta E - E technique have been used to identify protons, and a cutoff as low as 2.5 MeV is achieved. Suppression of events induced by neutrons in the low-energy tail of the neutron field is achieved by time-of-flight techniques. The data are normalized relative to elastic np scattering measured in the 20-degree telescope. Results from an accepted neutron spectrum are presented and some methods to correct for events from low energy neutrons are presented and evaluated. The data are compared with calculations using the nuclear code TALYS. It was found that TALYS systematically overestimates the compound part, and underestimates the pre-equilibrium part of the cross-section.