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Manuscript Title: DWBA calculations of continuum spectra of nuclear reactions.
Authors: T. Tamura, T. Udagawa, M. Benhamou
Program title: ORION-TRISTAR-1
Catalogue identifier: ABNL_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 29(1983)391
Programming language: Fortran.
Operating system: UT2D.
Program overlaid: yes
RAM: 20K words
Word size: 60
Peripherals: magnetic tape.
Keywords: Nuclear physics, Light ion, Direct nuclear reactions to continuum region, Transfer reaction, Inelastic scattering, Cross section, Analyzing power, Form factor, Density spectroscopic, Zero-range dwba.
Classification: 17.11.

Nature of problem:
ORION-TRISTAR-1 calculates the angle dependent continuum cross sections, for reactions induced by light ions. For the case of a polarized spin 1/2 projectile, it also calculates the analyzing power of the continuum. It can calculate further the cross sections for leaving the residual nucleus at varying excitation energies, as well as with a range of spin I and its projection M. These cross sections may be used as inputs for extended versions of Hauser-Feshbach type calculations. ORION produces DWBA (Distorted Wave Born Approximation) cross sections for a range of transferred angular momenta. They are multiplied in TRISTAR with corresponding spectroscopic densities, and are then added together, to obtain continuum cross sections.

The program may rather safely be used for light ions, whose incident energies do not exceed 30-40 MeV, if the reaction is of the inelastic or pickup type. For stripping type reactions, the breakup cross section might have to be added, in order to fit experimental spectra at the higher energy end and at smaller angles. For all three types of reactions, a Hauser-Feshbach cross section would have to be added to fit data at the lower energy end of the spectrum.

Running time:
The running time is roughly proportional to the maximum value of the transferred angular momentum, and also to the number of different Q- values, for which ORION calculates DWBA cross sections. The CPU time for the first example given in the present paper was about 14 s. A CDC DUAL CYBER 170/750 was used.