0000000000246465
AUTHOR
J. Thaysen
Spectroscopy at the drip line: the case of 31Ar
The beta decay of exotic nuclei is directly connected to many different and highly relevant issues. While along the years a hundred of nuclei have been identified as beta delayed proton (β-p) emitters only eight have been found to be β-2p emitters and the β-3p decay mode although energetically allowed has so far not been observed [1].
The β2p decay mechanism of Ar
We have measured the beta-decay of Ar-31 with a high granularity setup sensitive to multiparticle decay branches. Two-proton emission is observed from the isobaric analog state in Cl-31 to the four lowest states in P-29 and furthermore from a large number of states fed in Gamow-Teller transitions. The mechanism of two-proton emission is studied via energy and angular correlations between the two protons. In all cases the mechanism is found to be sequential yielding information about states in S-30 up to 8 MeV excitation energy. Improved data on the beta-delayed one-proton branches together with the two-proton data provide precise information about the beta-strength distribution up to 15 MeV…
Determination of the spin of 31Ar
Abstract The beta-delayed proton emission from the lightest Ar-isotopes has been recorded with a high-granularity, large solid-angle Si-detector set-up. Proton energy shifts due to beta-recoil have been measured. We demonstrate how this allows the spin of 31 Ar to be determined as 5/2. The method can be applied at decay rates as low as 1 s −1 .
Spectroscopy with β2p and β-ν recoil shifts
9 pages, 4 figures.-- Printed version published Apr 22, 2002.