A CVD diamond detector for (n, a) cross-section measurements

In astrophysics, the determination of the optical a-nucleus potential for low a-particle energies, crucial in understanding the origin of the stable isotopes, has turned out to be a challenge. Theory still cannot predict the optical potentials required for the calculation of the astrophysical reaction rates in the Hauser-Feshbach statistical model and there is scant experimental information on reactions with α particles at the relevant astrophysical energies. Measurements of (n, a) crosssections offer a good opportunity to study the α channel. At the n-TOF experiment at CERN, a prototype detector, based on the chemical vapor deposition (CVD) diamond technology, has been recently developed for (n, α) measurements. A reference measurement of the ¹⁰B(n, α)⁷Li reaction was performed in 2011 at n-TOF as a feasibility study for this detector type. The results of this measurement and an outline for future experiments are presented here.