1992 Fiscal Year Final Research Report Summary
Study of Radioactive Snowballs in Superfluid Helium
| Project/Area Number |
03044093
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | Osaka University |
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Principal Investigator |
TAKAHASHI Noriaki Osaka University, 教養部, 教授 (10028152)
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| Co-Investigator(Kenkyū-buntansha) |
HASS M ワイツマン研究所, 教授
REIF R ドレスデン工大, 教授
TRAUTMANN W GSI, 研究員
MUNZENBERG G GSI, 主任研究員
LYNEN Uli GSI, 教授
MIYATAKE Hiroari Osaka University, 教養部, 助手 (50190799)
ITAHASHI Takahisa Osaka University, 核物理研究センター, 助教授 (20112071)
FUJITA Yoshitaka Osaka University, 教養部, 助手 (60093457)
SHIMODA Tadashi Osaka University, 教養部, 助教授 (70135656)
HASS.MICHAEL Weizmann Institute of Science
REIF Roland Technical University Dresden
TRAUTMANN Wolfgang GSI
MUNZENBERG Gottfried GSI
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| Project Period (FY) |
1991 – 1992
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| Keywords | Superfluid helium / Impurity ion / Snowball / Cluster / Radioactive nuclear beam / betaray detection / GSI / SIS |
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| Research Abstract |
Impurity ions introduced in liquid helium may behave as singly charged entities with effective mass of 50-100 He atoms, which are referred to as snowballs. A snowball is. therefore, an aggregate, a micro-cluster of helium atoms by means of electrostriction around an impurity core ion admitted in liquid helium. not only helium ions as first noticed but also other alien ions do form snowballs. The method used in the of study of polarization phenomena in heavy ion reactions enabled us to conceive renewed interests to approach individual snowballs though alpha- and beta-ray countings, which have been developed here.
While the snowball has been thought of a highly paramount solid entity, there are still doubt whether all the existing evidences do decisively favor the picture of a solid core. The preservation of nuclear polarization in this research provided with an important clue to this issue, enabling us to test the inherent structure of snowballs directly as to peripheral problems of the above experiment.
The radioactive nuclear beams from the SIS accelerator at GSI Darmstadt was examined and finally focussed for of snowball experiments. The intensity and focussing were enough for that purpose.
The lifetime obtained for snowballs indicates the interaction responsible is not that with simple electrons but with basic excitations in liquid helium.
The structure of snowball became clearly highly symmetric, as it was compared with the crystal structure composed of metal ion and hydrogen ions. This is an interesting point of view for understanding of maintaining nuclear polarization in the core ion trapped in a snowball.
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[Publications] K.ASAHI,H.OKUNO,H.UENO,H.SATO,J.KURA,T.KUBO,T.NAKAMURA,N.INABE,A.YOSHIDA,Y.OKUBO,M.ADACHI,T.ICHIMURA.M.ISHIHARA,T.SHIMODA,H.MIYATAKE,N.TAKAHASHI,D.BEAUMEL,D.J.MORRISSEY,W.-D.Schmidt-Ott: "Spin-oriented projectile fragments:The first application to g-factor measurements" Hyperfine Interactions. 75. 101-108 (1992)
Description
「研究成果報告書概要(和文)」より
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[Publications] K. Asahi, H. Okuno, H. Ueno, H. Sato, J. Kura, T. Kubo, T. Nakamura, N. Inabe, A. Yoshida, Y. Okubo, M. Adachi, T. Ichimura., M. Ishihara, T. Shimoda, H. Miyatake, N. Takahashi, D. Beaumel, D. J. Morrissey, W. -D. Schmidt-Ott: "Spin-oriented projectile fragments : The first application to g-factor measurements" Hyperfine Interactions. 75. 101-108 (1992)
Description
「研究成果報告書概要(欧文)」より
