Isomeric yield ratios in proton-, sup 3 He-, and. alpha. -particle-induced reactions on sup 197 Au

Journal Article · Thu Mar 01 04:00:00 EST 1990 · Physical Review, C (Nuclear Physics); (USA)

DOI:https://doi.org/10.1103/PhysRevC.41.889· OSTI ID:6915430

Nagame, Y; Sueki, K; Baba, S; Nakahara, H ^[1]

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1. Department of Radioisotopes, Japan Atomic Energy Research Institute, Tokai-mura, Ibaraki 319-11 (JP) Japan Department of Chemistry, Faculty of Science, Tokyo Metropolitan University, Setagaya-ku, Tokyo 158, Japan (JP)

Excitation functions and mean projected recoil-ion ranges of the isomeric nuclei produced in proton-, {sup 3}He-, and {alpha}-particle-induced reactions on {sup 197}Au were measured by an activation technique for bombarding energies {ital E}{sub {ital p}}{approx lt}50 MeV, and {ital E} {sub {sup 3}He,{alpha}}{approx lt}40 MeV. Isomeric yield ratios ({sigma}{sub {ital m}}/{sigma}{sub {ital g}}) were determined as a function of the incident particle energy. The experimental excitation functions and isomeric yield ratios were compared with those from statistical model calculations based on the Hauser-Feshbach formalism. From the analysis of excitation functions, recoil-ion ranges, and isomeric yield ratios, the observed reactions were able to be grouped into three distinctly different ones in the energy region studied: (i) compoundlike reaction for ({ital p},3{ital n}), ({sup 3}He,4{ital n}), ({alpha},3{ital n}), and ({ital p},{ital pn}){sup 196}Au{sup {ital m}}, (ii) one-neutron stripping reaction for ({sup 3}He,2{ital p}), and (iii) nonequilibrium one-neutron knockout or pickup reactions with transfer of a small amount of angular momentum for the ({sup 3}He,{alpha}), ({alpha},{alpha}{ital n}), and ({ital p},{ital pn}){sup 196}Au{sup {ital g}} that are intermediate between (i) and (ii). We propose a semiempirical method which predicts isomeric yield ratios in the compoundlike reactions, within a factor of 0.7 to 1.4, from the spin distribution of the compound nucleus.

• OSTI ID: 6915430
• Journal Information: Physical Review, C (Nuclear Physics); (USA), Journal Name: Physical Review, C (Nuclear Physics); (USA) Vol. 41:3; ISSN 0556-2813; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

651920* -- Nuclear Properties & Reactions
A=190-219
Experimental
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA REACTIONS
BARYON REACTIONS
CHARGED-PARTICLE REACTIONS
COMPOUND-NUCLEUS REACTIONS
CROSS SECTIONS
DIRECT REACTIONS
ENERGY DEPENDENCE
ENERGY RANGE
EXCITATION FUNCTIONS
FUNCTIONS
GOLD 197 TARGET
HADRON REACTIONS
HAUSER-FESHBACH THEORY
HELIUM 3 REACTIONS
ISOMERIC NUCLEI
MATHEMATICAL MODELS
MEV RANGE
MEV RANGE 10-100
NUCLEAR REACTION YIELD
NUCLEAR REACTIONS
NUCLEAR THEORY
NUCLEI
NUCLEON REACTIONS
PICKUP REACTIONS
PROTON REACTIONS
RECOILS
STATISTICAL MODELS
STRIPPING
TARGETS
TRANSFER REACTIONS
YIELDS