Measurements of the S-33 (n, α)Si-30 cross-section at n_TOF and ILL: Implications in neutron capture therapy

Abstract

Up to a couple of years ago, the S-33 (n, alpha)Si-30 cross-section data had been limited and scarce. The origin in the solar system of S-36 had been the only motivation to study that cross-section. However, a few years ago, the S-33 (n, alpha)Si-30 reaction was proposed as a possible target in neutron capture therapy (NCT) due to the excellent bio-properties of S-33 and the significant resonance at 13.45 keV of the cross-section for which a high-energy alpha is emitted. Prior to the experiments carried out at n_TOF-CERN and at the Institut Laue-Langevin (ILL) facilities, the data situation was: no data from the thermal point up to 10 keV; from 10 keV to 300 keV, there was only one (n, alpha) measurement able to resolve the resonances with a questionable value of the 13.45-keV resonance; and the thermal point did not have a consistent value. Here we summarize three experiments that have been performed covering the whole energy range of interest in NCT and astrophysics. These experiments have solved the most important issues. The data of the present work and the evaluated data are used to calculate the dose rate in the tissue.