High spin isomer beam line at RIKEN
- Institute of Physical and Chemical Research, Saitama (Japan); and others
Nuclear high spin states have been the subject of extensive experimental and theoretical studies. For the production of high spin states, fusion reactions are usually used. The orbital angular momentum brought in the reaction is changed into the nuclear spin of the compound nucleus. However, the maximum induced angular momentum is limited in this mechanism by the maximum impact parameter of the fusion reaction and by the competition with fission reactions. It is, therefore, difficult to populate very high spin states, and as a result, large {gamma}-detector arrays have been developed in order to detect subtle signals from such very high spin states. The use of high spin isomers in the fusion reactions can break this limitation because the high spin isomers have their intrinsic angular momentum, which can bring the additional angular momentum without increasing the excitation energy. There are two methods to use the high spin isomers for secondary reactions: the use of the high spin isomers as a target and that as a beam. A high spin isomer target has already been developed and used for several experiments. But this method has an inevitable shortcoming that only {open_quotes}long-lived{close_quotes} isomers can be used for a target: {sup 178}Hf{sup m2} (16{sup +}) with a half-life of 31 years in the present case. By developing a high spin isomer beam, the authors can utilize various short-lived isomers with a short half-life around 1 {mu}s. The high spin isomer beam line of RIKEN Accelerator Facility is a unique apparatus in the world which provides a high spin isomer as a secondary beam. The combination of fusion-evaporation reaction and inverse kinematics are used to produce high spin isomer beams; in particular, the adoption of `inverse kinematics` is essential to use short-lived isomers as a beam.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- OSTI ID:
- 458913
- Report Number(s):
- ANL/PHY-97/1; CONF-9607156-; ON: DE97003376; TRN: 97:006986
- Resource Relation:
- Conference: Conference on nuclear structure at the limits, Argonne, IL (United States), 22-26 Jul 1996; Other Information: PBD: 1996; Related Information: Is Part Of Proceedings of the conference on nuclear structure at the limits; PB: 391 p.
- Country of Publication:
- United States
- Language:
- English
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