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

• Published in: Quantum Beam Science
• Main Authors: Javier Praena, Begoña Fernández, Miguel Macías, Ignacio Porras, María Pedrosa-Rivera, Hanna Koivunoro, Marta Sabaté-Gilarte, Fernando Arias de Saavedra
• Format: Article
• Language: English
• Published: MDPI AG 2025-09-01
• Subjects: experimental thermal cross section; sulfur-33; neutron-induced alpha emission; BNCT
• Online Access: https://www.mdpi.com/2412-382X/9/3/27

This work is focused on an accurate experimental determination of the thermal ³³S(<i>n</i>,<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>α</mi></semantics></math></inline-formula>)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(<i>n</i>,<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>α</mi></semantics></math></inline-formula>)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.