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Absolute differential cross sections for elastic p 4He, p 6He and p 8He small-angle scattering were measured in inverse kinematics with secondary 4,6,8He-beams at an energy near 0.7 GeV/u. The experiment was performed using beams from the heavy-ion synchrotron SIS and the fragment separator FRS of GSI Darmstadt. The hydrogen-filled ionization chamber IKAR served simultaneously as a gas target and a detector for the recoil protons. Projectile scattering angles were measured with multi-wire tracking detectors. For proton scattering from the neutron-rich isotopes 6He and 8He, differential elastic-scattering cross sections dσ/dt were deduced in the range 0.002 ≤ 0.05 (GeV/c)2 of the four-momentum transfer squared t. For elastic p 4He scattering, the data obtained in the t-range 0.002 ≤ 0.02 (GeV/c)2 supplement the results from an earlier work performed in direct kinematics. From the differential cross sections the integral elastic-scattering cross sections σel, the total cross sections σtot, and the total reaction cross sections σr for the proton–nucleus strong interaction were evaluated. The data obtained on dσ/dt allow the radial matter distributions in the 6He and 8He nuclei to be determined and the corresponding root-mean-square matter radii to be deduced. [Copyright &y& Elsevier]

Focuses on the left-right symmetry of the angular distribution of long-range alpha particles from ternary [sup 235]U fission induced by cold polarized neutrons. Electromagnetic interaction of particles; Contribution to the fission cross section; Detection of coincidences between pulses and diodes.

This paper presents the results of experimental investigations of (p,pn), (p,pα) and (p,p 6He) reactions with relativistic 6He and 8He beams impinging on a hydrogen target. Information on the structure of extremely neutron-rich nuclei was obtained by using the unique characteristic of quasi-free scattering processes and inverse kinematics. For the first time, momentum distributions of complex clusters inside 6He and 8He were measured. Spectroscopic factors for valence neutrons, α- and 6He clusters were deduced from the experimental data. They demonstrate that the filling of the p½ shell is the essential feature of the 8He structure. It is shown that the 8He cluster structure can be considered as a 6He core plus two valence neutrons. [Copyright &y& Elsevier]