Integral measurement of the ¹²C(n, p)¹²B reaction up to 10 GeV

Abstract

The integral measurement of the ¹²C(n, p)¹²B reaction was performed at the neutron time-of-flight facility n_TOF at CERN. The total number of 12B nuclei produced per neutron pulse of the n_TOF beam was determined using the activation technique in combination with a time-of-flight technique. The cross section is integrated over the n_TOF neutron energy spectrum from reaction threshold at 13.6 MeV to 10 GeV. Having been measured up to 1 GeV on basis of the ²³⁵U(n,f) reaction, the neutron energy spectrum above 200 MeV has been re-evaluated due to the recent extension of the cross section reference for this particular reaction, which is otherwise considered a standard up to 200 MeV. The results from the dedicated GEANT4 simulations have been used to evaluate the neutron flux from 1 GeV up to 10 GeV. The experimental results related to the ¹²C(n,p)¹²B reaction are compared with the evaluated cross sections from major libraries and with the predictions of different GEANT4 models, which mostly underestimate the 12B production. On the contrary, a good reproduction of the integral cross section derived from measurements is obtained with TALYS-1.6 calculations, with optimized parameters.