Orateur
Description
The NEA High priority Request List [Plompen:2007] features the neutron capture on 50Cr and 53Cr between 1 and 100 keV as very relevant for criticality safety. In the case of 50Cr, the product of the (n,γ) reaction is 51Cr, unstable with a half-life of 27.7 days which makes it suitable for neutron activation experiments. Although several time-of- flight experiments have been performed, including a recent one at the CERN n_TOF facility [Guerrero:2021]. Neutron activation should be in principle more accurate, but to date only one experiment has been published [Xia:2002], being the corresponding publication just a 2 pages conference proceeding.
In this work work we present an activation measurement performed last year at the CNA HISPANoS facility (Sevilla, Spain) to determine the (n,g) maxwellian-averaged cross section (MACS) of 50Cr. In addition to measure the activation to a neutron beam with a 30 keV quasi-maxwellian energy distribution -produced by the 7 Li(p,n) reaction with 1912 keV protons, and routinely employed in activation measurements- we applied a novel method to develop a quasi-maxwellian 90 keV beam, based on the superposition of the distributions produced via 7Li(p,n) reaction with different incident beam energies. The activation with a 90 keV MB distribution is of high interest for stellar nucleosynthesis studies, in particular to study the weak s-process. We will present preliminary results of the activation at 30 and 90 keV on 50Cr and 197Au, whose (n,g) cross section is well-known and its MACS at 30 keV is considered a standard.
