J. Péter

TONNERRE: an array for delayed-neutron decay spectroscopy

Abstract The design and construction of an array for delayed-neutron decay spectroscopy is presented. The array is composed of 32 plastic scintillator (BC400) modules each of which provide for time-of-flight (energy) and position measurements. The intrinsic detection efficiency is 30% at E n =2 MeV and the resolution δ E n / E n ∼10% (FWHM). The array can cover a total solid angle of up to 50% of 4π. Details of studies performed to optimize the performances of the individual modules are reported, as well as source testing and in-beam commissioning.

Beta-decay studies at the N=28 shell closure

Abstract First results on a β-γ decay spectroscopy experiment of nuclei in the region of N=28 are reported. New β half-lives for nuclei from Mg to Ar have been extracted. For the heavier ones, the new periods of 48Ar and 47Cl are of importance in the understanding of solar abundance ratio 48 Ca 46 Ca . The measured half-lives of Si isotopes have been extended from N=25 to N=28 and are discussed in the light of possible deformation occuring in this region. Finally, preliminary spectroscopy of 45Ar is also reported.

Incomplete fusion in nucleus-nucleus central collisions. Study of 40Ar on 27Al from 25 to 85 MeV/u☆

Abstract Light charged particles and fragments emitted in collisions between 40Ar between 25 and 85 MeV/u and 27Al target have been detected in a geometry close to 4π in the center of mass. An event by event analysis based on the use of the momentum sphericity tensor allowed to identify a significant fraction of the central collisions. The data show that an incomplete fusion nucleus is formed and decays via isotropic emission at all incident energies, although no heavy residue is left above 36 MeV/u. Fusion is less and less complete as the incident energy increases. Nevertheless, an increase in the multiplicity of charged particles shows that the average excitation energy increases.

Spectroscopy around N = 20 shell closure: β-n decay study of 35Al

An experimental spectroscopic investigation of

Spectroscopy near the N=20 shell closure: β-n decay studies of 33Mg and 35Al

^{35}

Beta-decay half-lives at the N = 28 shell closure

Al has been performed. The delayed neutron and

Spectroscopy at the N=20 shell closure: the β-decay of32Mg

gamma

β-decay studies at the N=28 shell closure: indications for a weakening of the spin-orbit force far from stability ?

spectra, following the

SPECTROSCOPY AT N=28 NEW EVIDENCES OF DEFORMATION

beta

Study of neutron-rich argon isotopes in β-decay

decay of