https://doi.org/10.1140/epja/i2008-10739-6
Regular Article - Experimental Physics
Properties of very n -rich He isotopes
1
Flerov Laboratory of Nuclear Reactions, JINR, RU-141980, Dubna, Russia
2
The Kurchatov Institute, RRC, Kurchatov sq. 1, 123182, Moscow, Russia
3
Institute of Nuclear Physics PAS, Henryk Niewodniczański, Cracow, Poland
4
GANIL, BP 5027, F-14076, Caen Cedex 5, France
5
IPN and CRC, University of Louvain, B-1348, Louvain-la-Neuve, Belgium
6
PNTPM, Université Libre de Bruxelles, Bruxelles, Belgium
7
Institut Pluridisciplinaire Hubert Curien, IN2P3/Université Louis Pasteur, Strasbourg, France
8
Institute of Experimental Physics, RNFC All-Russian Research, RU-607190, Sarov, Russia
9
NSCL Michigan State University, 48824-132, East Lansing, MI, USA
* e-mail: fomichev@jinr.ru
Received:
3
November
2008
Revised:
15
January
2009
Accepted:
24
January
2009
Published online:
5
March
2009
Low-energy spectra of the 8, 10He nuclei were investigated in the (t, p) -type reactions at small centre-of-mass angles using ∼ 25 AMeV beams of 6He and 8He nuclei. The 0+ ground state (g.s.) of 8He and excited states, 2+ at 3.6-3.9MeV and (1+) at 5.3-5.5MeV, were populated with cross-sections of 200, 100-250, and 90-125μb/sr, respectively. To account for a near-threshold anomaly observed in the 8He spectrum the population of a 1- continuum (soft dipole excitation) was considered. The lowest-energy group of events in the 10He spectrum was observed at ∼ 3 MeV with a cross-section of ∼ 140 μb/sr. This result is consistent with the previously reported observation of 10He providing a new g.s. position for 10He at about 3MeV.
© SIF, Springer-Verlag Berlin Heidelberg, 2009