Measurement of the 33S(n,α)30Si Thermal Cross-Section with Slow Neutrons at ILL

This work is focused on an accurate experimental determination of the thermal 33S(n,α)30Si cross-section. This cross-section is a critical parameter for the potential use of 33S as a cooperative target in boron neutron capture therapy or to understand its role in the stellar nucleosynthesis of 36S. At present, there are large discrepancies in this experimental value; therefore, in this work we measured it relative to the 10B(n,α)7Li standard cross-section at the high flux reactor of the Institut Laue-Langevin. The experimental setup was based on a double-sided silicon strip detector. Two 33S samples were used. One 10B sample was used as reference. Particular attention was taken to the characterization of the mass thickness of the samples before and after the experiment because of the high volatility of 33S. Such work was already published in a dedicated paper. A cross-check of the 10B sample was carried out with the neutron flux monitor at the n_TOF-CERN facility. The obtained cross-section of (280 ± 33) mb is significantly higher than the existing data.