''Extreme'' {gamma}-ray spectroscopy: single-neutron states in {sup 101}Sn and rotation of the proton emitter {sup 145}Tm
- Argomie National Laboratory, Argonne, IL 60439 (United States)
In-beam {gamma}-ray studies of nuclei with a large proton excess are faced with ever decreasing cross sections and large backgrounds due to strong less exotic reaction channels. However, many of the nuclei along the proton drip line {alpha} decay, proton decay or emit {beta}-delayed particles. This offers a very selective tag for prompt {gamma} rays and has been known as the Recoil-Decay Tagging (RDT) method. RDT has been extensively used with the Gammasphere array of Compton suppressed Ge detectors coupled with the Argonne Fragment Mass Analyzer. Recently, despite a very small cross section of about 50 nb and a long half life of {approx}2 s, protons emitted following the {beta} decay of {sup 101}Sn were used to identify {gamma}-ray transitions in {sup 101}Sn. As a result, the energy splitting between the neutron g{sub 7/2} and d{sub 5/2} orbitals outside the {sup 100}Sn core was deduced. The structure of light Sn isotopes is discussed in the framework of the shell model in light of the new results. Another state-of-the-art example is the observation of a rotational ground-state band in the fast proton emitter {sup 145}Tm, which decays with a half live of only {approx}3 {mu}s. In this experiment, coincidences between the proton decay to the 2{sup +} excited state in the daughter nucleus and the 2{sup +}{yields}0{sup +} {gamma}-ray transition were also measured, which constitutes the first direct proof of proton decay fine structure. Based on the data the possibility of a triaxial shape in {sup 145}Tm is considered.
- OSTI ID:
- 21039453
- Journal Information:
- AIP Conference Proceedings, Vol. 961, Issue 1; Conference: PROCON 2007: International conference on proton emitting nuclei and related topics, Lisbon (Portugal), 17-23 Jun 2007; Other Information: DOI: 10.1063/1.2827248; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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