Charged-particle spectrometry using a pencil-beam DT neutron source for double-differential cross-section measurement

Measurement of double-differential cross-sections of charged-particle emission induced by 14 MeV neutrons is quite important for estimating the nuclear heating and material damage of a fusion reactor. However, there are few experimental data available in spite of the importance of the nuclear reactions of light nuclei in fusion reactor development. In order to accurately measure differential cross-sections, especially of light nuclei, we propose a refined spectrometry system and a data processing method. The employment of a pencil-beam neutron source overcomes the fundamental difficulty of the measurement. As a result, a system with a counter telescope consisting of silicon surface barrier detectors satisfies high energy resolution and angular resolution, a wide detection energy range and adequate particle discrimination. To correct the energy loss of the emitted charged particles in the sample, a rigorous correction method by means of the unfolding procedure is applied. The validity and the capability of this spectrometry technique are confirmed from three basic measurements: the measurements of charged particles emitted from Teflon, α-particles emitted from the 27Al(n, xα) reaction and the protons recoiling from the 1H(n,n) reaction. This technique can be applied to the detailed DDXc measurements of various materials, especially of lighter materials, for fusion reactor modeling.