Eur. Phys. J. A (2009) 42: 465-469
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

Abstract

Low-energy spectra of the ^{8, 10}He 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.