Quasifree knockout in [sup 9]Be([alpha],2[alpha])[sup 5]He at an incident energy of 197 MeV

Journal Article · Tue Nov 01 04:00:00 EST 1994 · Physical Review, C (Nuclear Physics); (United States)

DOI:https://doi.org/10.1103/PhysRevC.50.2449· OSTI ID:6947739

Cowley, A A ^[1]; Steyn, G F; Foertsch, S V; Lawrie, J J; Pilcher, J V; Smit, F D; Whittal, D M ^[2]

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1. Department of Physics, University of Stellenbosch, Stellenbosch, 7600 (South Africa)
2. National Accelerator Centre, Faure, 7131 (South Africa)

Energy-sharing distributions have been measured at five quasifree angle pairs for the reaction [sup 9]Be([alpha],2[alpha])[sup 5]He at an incident energy of 197 MeV. In order to extract absolute spectroscopic factors, elastic scattering cross sections for [sup 4]He([alpha],[alpha])[sup 4]He were also measured at approximately the same incident energy, between center-of-mass angles of 40[degree] and 90[degree]. The knockout data are compared with distorted-wave impulse approximation theory. The extracted cluster spectrosopic factors are found to be in agreement with a theoretical estimate and also with existing results from ([ital p],[ital p][alpha]) studies. Consequently, this new result is in strong contrast to those from previous ([alpha],2[alpha]) studies at lower incident energies which yield spectroscopic factors significantly in excess of the expected values. The radial localization of the coincidence cross section in the target nucleus suggests that the observed incident energy dependence of the spectroscopic factors is related to the cluster-core nuclear density. Thus the cluster formation probability is enhanced in the region of very low nuclear density which is preferentially sampled by the ([alpha],2[alpha]) reaction at low incident energies.

• OSTI ID: 6947739
• Journal Information: Physical Review, C (Nuclear Physics); (United States), Journal Name: Physical Review, C (Nuclear Physics); (United States) Vol. 50:5; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

663110 -- General & Average Properties of Nuclei & Nuclear Energy Levels-- (1992-)
663440* -- D-
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663510 -- Nuclear Mass Ranges-- A=1-5-- (1992-)
663520 -- Nuclear Mass Ranges-- A=6-19-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA REACTIONS
BERYLLIUM 9 TARGET
CHARGED-PARTICLE REACTIONS
CLUSTER MODEL
CROSS SECTIONS
DIRECT REACTIONS
DISTORTED WAVE THEORY
ELASTIC SCATTERING
ENERGY DEPENDENCE
ENERGY RANGE
HELIUM 4 TARGET
IMPULSE APPROXIMATION
KNOCK-OUT REACTIONS
MATHEMATICAL MODELS
MEV RANGE
MEV RANGE 100-1000
NUCLEAR MODELS
NUCLEAR REACTIONS
OPTICAL MODELS
QUASI-ELASTIC SCATTERING
QUASI-FREE REACTIONS
SCATTERING
SPECTROSCOPIC FACTORS
TARGETS