The status of new fragment separator ACCULINNA-2 project and the first day experiments

The new facility fragment separator ACCULINNA-2 will be put into operation at the beginning of 2015 in FLNR JINR. The new separator is destined to add considerably to the studies of drip-line nuclei performed with the use of variety of direct reactions known to be distinctive to the 15 – 50 MeV/amu exotic secondary RIBs. Intense beams provided by the U-400M cyclotron will ensure the achievement of this objective. In addition to the RIB separation accomplished by means of the dipole-wedge-dipole selection, the addition of a zero-degree dipole magnet setup is foreseen. A long (13 m) straight section will provide precise time-of-flight measurements

Experimental study of 4^{4}H in the reactions 2^{2}H(t,p) and 3^{3}H(t,d)

Triton beam; Tritium target; Deuterium target; Transfer reactions; Resonance state

Recent results related to excited states of 6Be and 10He

The 1H(6Li,6Be)n charge-exchange reaction and the 3H(8He, p)10He two-neutron transfer reaction were recently carried out at the ACCULINNA fragment separator (FLNR, Dubna) to populate the ground and excited states of 6Be and 10He nuclei, respectively. The 6Be ET spectrum (ET is the 6Be energy above its 4He+p+p decay threshold) was obtained with high statistics and described by the well-known 0+ ground state of 6Be at ET = 1.37 MeV, the 2+ state at ET = 3.05 MeV and a broad structure extending from 4 to 16 MeV which could be interpreted as the isovector soft dipole mode associated with the 6Li ground state. In the 10He case the 0+ ground state was found at about 2.1(2) MeV (T ∼ 2 MeV) above the 8He+n+n breakup threshold. Angular correlations observed for 10He decay products show prominent interference patterns allowing to draw conclusions about the structure of low-energy excited states: 1- (E T ∼ 5 MeV) and 2+ (ET > 6 MeV)

Properties of very n-rich He isotopes

International audienceLow-energy spectra of the 8,10He nuclei were investigated in the (t, p)-type reactions at small centre-of-mass angles using ∼ 25AMeV 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 90-125 μb/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 ∼ 3MeV 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

Low-Energy Spectra of 8^{8}He and 10^{10}He Studied in (t,p) Type Reactions in Inverse Kinematics

International audienceMissing mass spectra for 8He and 10He obtained in the reactions 3H(6He, p)8He and 3H(8He, p)10He, respectively, are presented