(n, α) Reaction on ¹²C Induced by 14.1 MeV Neutrons

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

“…The anticoincidence spectrum above those threshold energies for protons and tritons therefore originates only from -particles or particles heavier than -particles. In the present measurement, recoiling carbon and 9 Be particles emitted via the 12 C(n,) 9 Be reaction have to be considered. Also, very small backgrounds due to the Si(n,x) and Si(n,xp) reactions exist.…”

“…Some proton signals that might have originated from water vapor impurities on the surface of the sample material are identified on the left side in the figure. In obtaining the anticoincidence spectrum of the ÁE detector, the respective contributions from the recoiling carbon and 9 Be particles emitted from the 12 C(n,) 9 Be reaction were calculated and subtracted. The energy loss of the particles in the sample material was estimated with the SRIM-2003 codes 14) combined with the codes that we have made, which considered the transport between the sample and the detectors.…”

“…The correction for recoiling carbons was made in a more forward angle than 70 . The correction for 9 Be particles was made in a more forward angle than 90 . At more backward angles, the energy of the emitted particles became lower than the threshold energy of the present measurement and their contributions were not included in obtained spectra.…”

“…4. The angular distribution of emitted 9 Be was derived from our measurements of the 12 C(n,) 9 Be reaction (see Section IV.2), for which no evaluation is given in any nuclear data library. Backgrounds due to the Si(n,x) and Si(n,xp) reactions in the ÁE detector were estimated by sample-out measurement and subtracted although their contribution was quite small.…”

“…Many background charged particles also disturb the measurement. A previous measurement by Haight et al resulted in the only existing comprehensive DDX data for -particles, 6) although several early studies [7][8][9][10][11] were carried out to investigate the 12 C(n, 0 ) 9 Be (ground state) reaction. Such scant experimental data for -particles have hindered consistent analysis, and a satisfactory reaction model has not yet been established.…”