Study of the fast-neutron-induced breakup reactions on lithium isotopes.

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Absolute differential cross sections and angular distributions of charged particles (deuterons and tritons) for fast neutron induced reactions on ^<6,7>Li were measured using 14.1 MeV T-d neutrons provided by the Rikkyo University 300 kV Cockcroft-Walton accelerator and two counter telescopes. Each of the counter telescopes consisted of two has proportional counters and two Si detectors (for the E and E measurements). The tragets of 95.58% enriched ^6Li and 99.988% ^7Li metal were prepared by rolling. The thicknesses of the ^<6,7>Li targets are 3.70 0.14 and 3.90 0.06 mg/cm^2, respectively.The experimental data obtained were analyzed by the distorted wave born approximation (DWBA) and the final-state interaction (FSI) theories. The measured energy spectra of d and t from the break-up reactions of the three-body finalstate ^6Li(n,d)^5He and ^7Li(n,t)^5He were reproduced in shape by a simple FSI theory. In the case of ^7Li, a contribution from the 7/2 state t-alpha FSI was found remarkably as well as a peak of the 3/2 state n-alpha FSI enhancement. The observed features of angular distributions for these two reactions as well as the two-body reactions ^6Li(n,t)^4He and ^7Li(n,d)^6He were fairly reproduced by DWBA calculations, and the observed spectroscopic factors were consistent with shell-model predictions.