85 research outputs found
High-precision measurement of the half-life of Ga
The beta-decay half-life of 62Ga has been studied with high precision using
on-line mass separated samples. The decay of 62Ga which is dominated by a 0+ to
0+ transition to the ground state of 62Zn yields a half-life of T_{1/2} =
116.19(4) ms. This result is more precise than any previous measurement by
about a factor of four or more. The present value is in agreement with older
literature values, but slightly disagrees with a recent measurement. We
determine an error weighted average value of all experimental half-lives of
116.18(4) ms.Comment: 9 pages, 5 figures, accepted for publication in PR
Tentative de description du noyau La par la methode de couplage quasiparticule-phonon plus rotor
Pas de résum
Beta-decay branching ratios of 62Ga
Beta-decay branching ratios of 62Ga have been measured at the IGISOL facility
of the Accelerator Laboratory of the University of Jyvaskyla. 62Ga is one of
the heavier Tz = 0, 0+ -> 0+ beta-emitting nuclides used to determine the
vector coupling constant of the weak interaction and the Vud quark-mixing
matrix element. For part of the experimental studies presented here, the
JYFLTRAP facility has been employed to prepare isotopically pure beams of 62Ga.
The branching ratio obtained, BR= 99.893(24)%, for the super-allowed branch is
in agreement with previous measurements and allows to determine the ft value
and the universal Ft value for the super-allowed beta decay of 62Ga
The beta-decay of 22Al
In an experiment performed at the LISE3 facility of GANIL, we studied the
decay of 22Al produced by the fragmentation of a 36Ar primary beam. A
beta-decay half-life of 91.1 +- 0.5 ms was measured. The beta-delayed one- and
two-proton emission as well as beta-alpha and beta-delayed gamma decays were
measured and allowed us to establish a partial decay scheme for this nucleus.
New levels were determined in the daughter nucleus 22Mg. The comparison with
model calculations strongly favours a spin-parity of 4+ for the ground state of
22Al
Q-value of the superallowed beta decay of Ga-62
Masses of the radioactive isotopes 62Ga, 62Zn and 62Cu have been measured at
the JYFLTRAP facility with a relative precision of better than 18 ppb. A Q_EC
value of (9181.07 +- 0.54) keV for the superallowed decay of 62Ga is obtained
from the measured cyclotron frequency ratios of 62Ga-62Zn, 62Ga-62Ni and
62Zn-62Ni ions. The resulting Ft-value supports the validity of the conserved
vector current hypothesis (CVC). The mass excess values measured were (-51986.5
+-1.0) keV for 62Ga, (-61167.9 +- 0.9) keV for 62Zn and (-62787.2 +- 0.9) keV
for 62Cu.Comment: 12 pages, 3 figures, 2 tables, submitted to Phys. Lett. B. v2: added
acknowledgement
Beta-decay properties of Si and P
The -decay properties of the neutron-deficient nuclei Si and
P have been investigated at the GANIL/LISE3 facility by means of
charged-particle and -ray spectroscopy. The decay schemes obtained and
the Gamow-Teller strength distributions are compared to shell-model
calculations based on the USD interaction. B(GT) values derived from the
absolute measurement of the -decay branching ratios give rise to a
quenching factor of the Gamow-Teller strength of 0.6. A precise half-life of
43.7 (6) ms was determined for P, the - (2)p decay mode of which
is described
First direct observation of two protons in the decay of Fe with a TPC
The decay of the ground-state two-proton emitter 45Fe was studied with a
time-projection chamber and the emission of two protons was unambiguously
identified. The total decay energy and the half-life measured in this work
agree with the results from previous experiments. The present result
constitutes the first direct observation of the individual protons in the
two-proton decay of a long-lived ground-state emitter. In parallel, we
identified for the first time directly two-proton emission from 43Cr, a known
beta-delayed two-proton emitter. The technique developped in the present work
opens the way to a detailed study of the mechanism of ground-state as well as
beta-delayed two-proton radioactivity.Comment: 4 pages, 5 figure
First observation of 54Zn and its decay by two-proton emission
The nucleus 54Zn has been observed for the first time in an experiment at the
SISSI/LISE3 facility of GANIL in the quasi-fragmentation of a 58Ni beam at 74.5
MeV/nucleon in a natNi target. The fragments were analysed by means of the
ALPHA-LISE3 separator and implanted in a silicon-strip detector where
correlations in space and time between implantation and subsequent decay events
allowed us to generate almost background free decay spectra for about 25
different nuclei at the same time. Eight 54Zn implantation events were
observed. From the correlated decay events, the half-life of 54Zn is determined
to be 3.2 +1.8/-0.8 ms. Seven of the eight implantations are followed by
two-proton emission with a decay energy of 1.48(2) MeV. The decay energy and
the partial half-life are compared to model predictions and allow for a test of
these two-proton decay models.Comment: 4 pages, 4 figures, accepted for publication in PR
Precision measurement of the half-life and the decay branches of 62Ga
In an experiment performed at the Accelerator Laboratory of the University of
Jyvaskyla, the beta-decay half-life of 62Ga has been studied with high
precision using the IGISOL technique. A half-life of T1/2 = 116.09(17)ms was
measured. Using beta-gamma coincidences, the gamma intensity of the 954keV
transition and an upper limit of the beta-decay feeding of the 0+_2 state have
been extracted. The present experimental results are compared to previous
measurements and their impact on our understanding of the weak interaction is
discussed.Comment: 7 pages, 7 figures, submitted to EPJ
A new isomer in La
Levels in La have been studied via /EC decay of on-line
mass-separated Ce using the HIGISOL technique. A new (390 40) ms isomer
is definitely attributed to La by conversion electron measurements of the 107 keV E3
isomeric transition
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