Gamow-Teller strength in the ( p , n ) reaction at 136 MeV on sup 20 Ne, sup 24 Mg, and sup 28 Si

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Physical Review, C (Nuclear Physics); (USA)

DOI:https://doi.org/10.1103/PhysRevC.43.50· OSTI ID:6098794

Anderson, B D; Tamimi, N; Baldwin, A R; Elaasar, M; Madey, R; Manley, D M; Mostajabodda'vati, M; Watson, J W; Zhang, W M ^[1]; Foster, C C ^[2]

---

1. Department of Physics, Kent State University, Kent, Ohio 44242 (USA)
2. Indiana University Cyclotron Facility, Bloomington, Indiana 47408 (USA)

Gamow-Teller (GT) strength distributions were studied in the ({ital p},{ital n}) reaction at 136 MeV on the self-conjugate {ital s}-{ital d} shell nuclei {sup 20}Ne, {sup 24}Mg, and {sup 28}Si. The measurements were performed in two separate experiments with the beam-swinger neutron time-of-flight facility at the Indiana University Cyclotron Facility. The flight paths were 91 and 131 m, respectively, for the two experiments. The neutrons were detected in large-volume plastic-scintillation detectors. The overall time resolutions were about 825 ps; this provided energy resolutions from 300 to 400 keV. GT strength was identified as {Delta}{ital l}=0 contributions in transitions to discrete final states and also in the background and continuum. The 0{degree}, {Delta}l=0 cross sections were converted to {ital B}(GT) units using a universal'' conversion formula calibrated to ({ital p},{ital n}) reactions on other even-even {ital s}-{ital d} shell nuclei. The resulting {ital B}(GT) distributions were compared with full {ital s}-{ital d} shell-model predictions. The distribution for {sup 24}Mg is described well, but the distributions for {sup 20}Ne and {sup 28}Si are described poorly. The total {ital B}(GT) strength observed in discrete states (up to 12 MeV of excitation) for each reaction is 65{plus minus}10 % of that predicted. If one considers {ital B}(GT) strength observed in the continuum above a calculated quasi-free-scattering background, the strength increases to 70--100 % of that predicted. If one considers {ital B}(GT) strength in an analysis of the full continuum (up to {similar to}20 MeV), the entire amount predicted may be observed. These results are consistent with that observed in other light nuclei.

• OSTI ID: 6098794
• Journal Information: Physical Review, C (Nuclear Physics); (USA), Journal Name: Physical Review, C (Nuclear Physics); (USA) Vol. 43:1; ISSN 0556-2813; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

651420* -- Nuclear Properties & Reactions
A=20-38
Experimental
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARYON REACTIONS
BARYONS
CHARGE-EXCHANGE REACTIONS
CHARGED-PARTICLE REACTIONS
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
FUNCTIONS
GAMOW-TELLER RULES
HADRON REACTIONS
HADRONS
MAGNESIUM 24 TARGET
MEV RANGE
MEV RANGE 100-1000
NEON 20 TARGET
NEUTRONS
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUCLEONS
PROTON REACTIONS
SILICON 28 TARGET
STRENGTH FUNCTIONS
TARGETS