Inclusive (p,α) reactions onAl27,Co

Abstract

Measurements of inclusive ( p,␣) reactions on 27 Al, 59 Co, and 197 Au at incident energies between 120 and 200 MeV are compared with the trend expected from systematics and also with calculations based on a statistical multistep direct reaction theory. Although reasonable agreement is obtained between the experimental angular distributions and the predictions of the parametrized systematics at various emission energies, significant discrepancies are nevertheless observed. Calculations with the quantum-mechanical multistep formulation confirm that the higher-step contributions are more important at these incident energies than found in a previous study at lower projectile energies. ͓S0556-2813͑96͒03007-5͔

Pre-equilibrium mechanisms in theNb93(p⃗,α)inclusive reaction at incident energies from 65 to 160 MeV

“…The possible simultaneous importance of all these characteristics is suggested by the observation (see for example Refs. [10,14]) that experimental pre-equilibrium cross section distributions of all types appear to follow closely the simple phenomenological systematics of Kalbach [41]. Consequently, implementation of a single truly global optical potential which satisfy all requirements is highly desirable.…”

“…[5,14]. These cross section distributions were extracted by means of a FKK multistep direct reaction theory, which reproduces experimental inclusive (p, p ′ ) quantities [5] on target nuclei which are close to those needed for this work, and in an appropriate incident energy range.…”

“…Of course, three-nucleon pickup as well as knockout could both be important processes in proton-induced emission of α particles. However, in one of our early investigations with unpolarized projectiles [14] at incident energies between 120 and 200 MeV the experimental cross section angular distributions of the reaction 59 Co(p,α) at various emission energies were fairly reliably reproduced by invoking only a knockout mechanism in the theoretical analysis. Also, in our recent paper [15] on the reaction 93 Nb( p,α) at an incident energy of 160 MeV, we found that best agreement of the theoretical predictions with experimental cross section and analyzing power angular distributions is obtained if knockout is assumed as the dominant mechanism.…”

59Co($\vec p$,α) reaction at 100 MeV incident energy – statistical multistep direct reaction into the continuum of outgoing energies

“…[9,10]. These cross section distributions which were extracted by means of a FKK multistep direct reaction theory, reproduce experimental inclusive (p, p ) quantities [9].…”

Recent insight into the mechanism of proton-induced composite particle emission in inclusive reactions

“…In comprehensive studies [3][4][5] of the (p,α) reaction to the continuum of excitation on various targets at incident energies in the range of interest from 65 to 200 MeV, with one notable exception, we identify the knockout process as terminating a statistical multistep mechanism. In these studies, analyzing power angular distributions at various emission energies are very sensitive to identify both the intranuclear statistical N-N multisteps, and also the terminating process leading to emitted α-particles.…”