Stellar cross sections forS33(n,α)30<

Abstract

The cross section of the S(n, n) Si reaction was measured in a neutron energy spectrum yielding the stellar rate for a thermal energy of kT=25 keV. For the Cl(n, p) S reaction, the experiment was performed in the neutron energy range from 10 to 260 keV. Our new result for S resolves the problem of a large discrepancy between two previous experiments. In case of Cl it could be shown that the (n, cx) channel is negligibly small compared to the (n, p) reaction at s-process conditions. The present results are used for a detailed discussion of a possible s-process origin of the rare neutron-rich isotope S. PACS number(s): 25.40.Ny, 97.10.Cv, 27.30.+t, 29.40.Cs

Neutron-induced nucleosynthesis

“…In some cases the (n,p) and (n,o 0 reactions even dominate over the (n,7) process and hence modify the nucleosynthesis path (see, e.g., Schatz et al 1995;Wagemans et al 1995).…”

“…The s-process production of 36 S was recently discussed quantitatively by Schatz et al, (1995) but without a reliable 36S(n,3,) cross section. The s-process reaction network in the sulfur to calcium region contains (n,7), (n,p), and (n,oz) reactions.…”

Measurement of the 33 S(n,α) cross-section at n_TOF(CERN): Applications to BNCT

“…7 Only one dedicated measurement of 33 S(n,␣) cross-section can be found in the literature 3 since the other measurements do not provide new specific data for BNCT. 4,5 Such measurement provided data from 10 keV to 1 MeV, thus the cross-section is unknown for neutron energies below 10 keV, the most important range for BNCT since neutrons are moderated by the tissue. Furthermore, there is only one measurement of the (n,tot) cross-section.…”

The33S(n,α)30Si cross section measurement at n_TOF-EAR2 (CERN): From 0.01 eV to the resonance region

“…The 33 S(n,α) reaction is of interest in astrophysics due to the still open question about the origin of 36 S [15] but also in Neutron Capture Therapy (NTC). 33 S could be used in combination with 10 B for treating superficial tumours [16] in accelerator based neutron sources where the energy of the neutron beam is in the epithermal energy region within which 33 S(n,α) shows resonances with a cross section higher than the one of 10 B(n,α) reaction.…”