Measurement and Analysis of Neutron-Induced Alpha Particle Emission Double-Differential Cross Section of Carbon at 14.2 MeV

Abstract

We carried out a detailed measurement of the neutron-induced -particle emission double-differential cross section of carbon at 14.2 MeV, for which there are few measured data in spite of its importance in many applications. In our measurement, a superior S/N ratio, high angular/energy resolutions and a wide detection energy range were realized with a pencil DT neutron beam and a countertelescope system. The obtained cross section for the 12 C(n, 0 ) 9 Be (ground state) reaction agreed well with the results of previous experiments and evaluated nuclear data. The obtained angular-differential cross section of the 12 C(n,n 0 +3) reaction for -particles showed a strong forward-peaked distribution that suggested a significant contribution of the direct reaction process to the 3 breakup. We attempted to calculate the emitted particle spectra by a Monte Carlo method and estimate the branching ratio of the channels that contribute to the 12 C(n,n 0 +3) reaction. As a result, it was found that the 12 C(n,) 9 Be à channels play an important role in generating the experimental double-differential cross section both of emitted -particles and neutrons. The estimated ratio of the 12 C(n,) 9 Be à channels was approximately 40%, somewhat larger than those evaluated in previous studies.

Measurement of 12C(n,n’) reaction cross section to determine triple-alpha reaction rate in high-density environments

“…mb. This cross section is consistent with the previous one of σ = 8.4 mb reported by Kondo et al [7], demonstrating the validity of our method using the MAIKo active target.…”

“…± 2(syst.) mb σ (Previous [7]) 8.4 mb categorized as a candidate of the signal event, the eye scanner recorded the coordinates of the vertex position of three alpha trajectories and the end points of the trajectories in the anode and cathode images by mouse clickings. The kinetic energy and momentum of each alpha particle were calculated from the vector between the vertex position and the end point using a computer program SRIM [5].…”

Measurement of Charged-Particle Emission Double-Differential Cross Section of Fluorine for 14.2MeV Neutrons

“…The proton, deuteron, and triton emission cross sections of carbon are so small at 14.2 MeV that the measured spectra only originated from fluorine. The contribution of -particles emitted from carbon was subtracted by using our previously measured -particle emission DDX data 3) in order to obtain -particle spectra only from fluorine. Two sets of a counter-telescope system with a pair of ÁE-E silicon surface barrier detectors were employed to distinguish different kinds of emitted charged particles.…”

“…We have recently developed an improved measurement system for secondary charged particles using a pencil DT-neutron beam furnished at the Fusion Neutronics Source (FNS) facility of the Japan Atomic Energy Agency (JAEA) 1) and have carried out systematic measurements of the charged-particle emission DDX for light nuclides. 2,3) In this paper, a measurement for fluorine is described in detail. Fluorine is contained in FLiBe (Li 2 BeF 4 ), which is a promising liquid blanket material in fusion reactors.…”