Neutron decay from the isobaric analog state in {sup 120}Sb populated in {sup 120}Sn({sup 3}He,{ital t}){sup 120}Sb at {ital E}({sup 3}He) = 200 MeV, {theta} = 0{degree}
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)
- Kernfysisch Versneller Instituut, Zernikelaan 25, 9747 AA Groningen (Netherlands)
- Indiana University Cyclotron Facility, Bloomington, Indiana 47405 (United States)
- Department of Natural Sciences, University of Michigan, Dearborn, Michigan 48128 (United States)
- King Abdul-Aziz University, Jeddah (Saudi Arabia)
The {sup 120}Sn({sup 3}He,{ital t}){sup 120}Sb charge-exchange reaction has been investigated at {ital E}({sup 3}He) = 200 MeV and {theta}{approx}0{degree} to study neutron decay from the isobaric analog state at {ital E}{sub {ital x}}=10.20 MeV in {sup 120}Sb. The low-energy neutrons (average energy {similar_to}0.85 MeV) were detected in coincidence with tritons observed in the focal plane of a high-resolution magnet spectrometer. Four small deuterated NE230 scintillation detectors were mounted at distances of 9.5 cm from the target resulting in an overall neutron detection efficiency including solid angle of {gt}1%. This efficiency was obtained by combining the measured dependence on neutron energy with a calculated neutron evaporation spectrum. From the measured ratio of coincidence to singles events a branching ratio of {gt}86% was deduced for neutron decay. The observation of isospin-violating neutron decay with a branching ratio close to 100% is in agreement with the expectation that the escape width ({Gamma}{sup {up_arrow}}) of the isobaric analog state in {sup 120}Sb is small compared to its spreading width ({Gamma}{sup {down_arrow}}). Triton spectra measured in coincidence with {gamma} rays from the deexcitation of the final nucleus display pronounced structures related to the thresholds for neutron emission, in agreement with the characteristics of calculated evaporation spectra.
- OSTI ID:
- 249479
- Journal Information:
- Physical Review, C, Vol. 52, Issue 3; Other Information: PBD: Sep 1995
- Country of Publication:
- United States
- Language:
- English
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