372596160

132

RIKEN Accel. Próg. Rep. 24 (1990)

IV-5. Cross Sections Calculated by an ALICE Codę

in the A = 50 — 60 Region

A. Hashizume, Y. Tendow, and K. Kitao

In Order to know the applicability of a hybrid model to the calculations of cross sections in-duced by charged particie reactions, an Alice Livermore codę was tested in the mass region A = 50 —67, and the results were compared with experiment. The purposes of these calculations are to obtain the best combination of parameters to reproduce experimental results and to know the limit of its reproducibilities. Calculations were performed with a FACOM M780 Computer. In this mass region, several attempts have been madę to analyze excitation functions; however, it was sometimes difficult to fit calculated results to experiment.

In this study, p, d, ³He, and ^-particles were chosen as incident ions. The calculations of cross sections were madę for 41 targets in the energy region up to 100MeV of incident particles. Exper-imental data were collected from the literaturę. When data were given only by figures, we got numerical data from the figures with an aid of a digitizer.

In the reactions which follow complete com-pound reactions, absolute peak values and peak widths can reproduce the experimental results fairly well for p or ^-particie incident. However, in the energy region where a pre-compound pro-cess is dominant, the results of calculation depend sensitively on the number of excitons, and can hardly reproduce the absolute value and slope of curves of experimental results. It should be pointed out that the energy spectra of emis-sion particles are needed to decide the number of initial excitons. In Fig. 1, the results of calculations on the ⁶⁵Cu(p, n)⁶⁵Zn reactions are shown. Experimental data are taken from Ref. 1. The results of ⁵⁴Fe(p, p2n)⁵²Fe and ⁶⁵Cu(^, 2n)⁶⁷Ga are shown in Fig. 2 and 3, respectively.

For d- and ³He-induced reactions, it is difficult to deduce generał conclusion because less experi-mental results have been reported than those for p or a-particle induced reactions. In addition, large discrepancies between calculation and experiment were observed in some reactions. Calculations for parameter search are still performing for these reactions.

(p.p2n)

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Fig. 2. Excitation function of ⁵⁴Fe(p, p2n)^S2Fe and the calculated curve.

Fig. 1. Excitation function of ^6SCu(p, n)^b5Zn reaction. The number of exciton is shown by a symbol (a_u (k> a*), where a_x is the initial exciton number, (h is the initial excited neutron number and a* is the initial excited proton number.

Fig. 3. Excitation function of ⁶⁵Cu(a\ 2n)⁶⁷Ga and the calculated curves.

References

1) A. Hashizume, Y. Tendow, Y. Ohkubo, and K. Kitao: RIKEN Accel. Próg. Rep., 21, 186 (1987).