Effect of the α Production Process on the Direct Reaction for the <SUP>7</SUP>Li Projectile

초록

We investigate the effect of the breakup process on the direct reaction ( DR) for Li-7. In order to study this effect, we introduce the theoretical ratio factor, R-th, and the average value of the ratio factor is 0.92. The ratio factor is close to unity in the below-barrier region because many of the alpha particles separated from the breakup process of Li-7 are not captured by the target nuclei. As a result, the alpha production cross sections become the main portion of the DR cross sections. However, the value of R-th in the above-barrier region are gradually suppressed because the alpha particles at energies above the Coulomb-barrier energy can be captured easily by the target. Using the center-of-mass energy regions of alpha particles, we investigate the difference of the R-th values between Li-6 + Bi-209 and Li-7 + Bi-209 systems in the above-barrier region, and we find that this difference is attributed to a reduction of the alpha capture cross-sections for the Li-7 + Bi-209 system.

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