Performance tests of a LaBr 3 :Ce detector coupled to a SiPM array and the GET electronics for γ -ray spectroscopy in a strong magnetic field

International audienceMeasurements have been performed with scintillation crystals of LaBr 3 :Ce coupled to an array of Silicon Photomultipliers (SiPMs) in a 3 T magnetic field. The SiPMs were read out by digital data acquisition systems, including the GET electronics system. Inside of the B-field, energy resolution values of 3.82% FWHM at 661.7 keV are reported for a 1.5 \protect \relax \special {t4ht=′}\protect \relax \special {t4ht=′} cubic LaBr 3 :Ce crystal coupled to a 6 × 6 array of 6 × 6 mm 2 SiPMs. No measurable degradation in energy resolution due to the presence of the strong magnetic field was observed

Validation of the energy-loss response of α particles in iC4_4H10_{10} with ACTARSim

International audienceACTARSim is a framework based on Geant4 and ROOT to simulate the response of active targets for nuclear physics experiments with radioactive beams. In this paper, we present the performance of the simulations for the energy-loss profile, total energy, range and angular resolution of the reconstructed track. Validation of the ACTARSim software against experimental data was performed in iC 4 H 10 with a mixed alpha source using the ACTAR TPC demonstrator. The results show a good agreement with the simulations indicating the validity of the models used in ACTARSim for α -particles in iC 4 H 10

Upgrade of the SPIRAL identification station for high-precision measurements of nuclear β decay

The low-energy identification station at SPIRAL (Système de Production d'Ions Radioactifs Accélérés en Ligne) has been upgraded for studying the β decays of short-lived radioactive isotopes and to perform high-precision half-life and branching-ratio measurements for superallowed Fermi and isospin T=1/2 mirror β decays. These new capabilities, combined with an existing Paul trap setup for measurements of β-ν angular-correlation coefficients, provide a powerful facility for investigating fundamental properties of the electroweak interaction through nuclear β decays. A detailed description of the design study, construction, and first results obtained from an in-beam commissioning experiment on the β+ decays 14 O and 17F is presented

High-Precision Half-life Measurements for the Superallowed β\beta+ Emitter 14^{14}O

The half-life of 14O, a superallowed Fermi emitter, has been determined via simultaneous and counting experiments at TRIUMF's Isotope Separator and Accelerator facility. Following the implantation of 14O samples at the center of the 8 spectrometer, a counting measurement was performed by detecting the 2313 keV rays emitted from the first excited state of the daughter 14N using 20 high-purity germanium (HPGe) detectors. A simultaneous counting experiment was performed using a fast plastic scintillator positioned directly behind the implantation site. The results, T1=2( ) = 70:632 0:094 s and T1=2( ) = 70:610 0:030 s, are consistent with one another and, together with eight previous measurements, establish a new average for the 14O half-life of T1=2 = 70:619 0:011 s with a reduced 2 of 0.99

High-precision half-life measurements for the superallowed Fermi β+ emitter 14^{14}O

Expérience TRIUMF/ISA

Study of the β−\beta^{-} decay of116m1^{116m1}In: A new interpretation of low-lying 0+^{+} states in116^{116}Sn

International audienceThe$^{116}$Sn nucleus contains a collective rotational band originating from proton $\pi$ 2p-2h excitations across the proton $Z=50$ shell gap. Even though this nucleus has been extensively investigated in the past, there was still missing information on the low-energy interband transitions connecting the intruder and normal structures. The low-lying structure of$^{116}$Sn was investigated through a high-statistics study of the $\beta^{-}$ decay of$^{116m1}$In with the $8\pi$ spectrometer and its ancillary detectors at TRIUMF. These measurements are critical in order to properly characterize the $\pi$ 2p-2h rotational band. Weak $\gamma$ -decay branches are observed utilizing $\gamma$ - $\gamma$ coincidence spectroscopy methods, leading to the first direct observation of the 85 keV $2_{2}^{+}\rightarrow 0_{3}^{+}$ $\gamma$ ray with a transition strength of $B(E2) = 99.7(84)$ W.u. The analysis of these results strongly suggests that the 2027 keV $0_{3}^{+}$ state should replace the previously assigned 1757 keV $0_{2}^{+}$ state as the band-head of the $\pi$ 2p-2h rotational band

High-Precision Half-Life Measurements for the Superallowed β+ Emitter 10^{10}C: Implications for Weak Scalar Currents

International audienc

Conversion-electron spectroscopy and gamma-gamma angular correlation measurements in 116^{116}Sn

International audienceThe$^{116}$Sn nucleus was studied via the $\beta^{-}$ decay of$^{116}$In utilizing the $8\pi$ spectrometer and its auxiliary detectors at TRIUMF-ISAC. The resulting K-shell conversion coefficients, K/L ratios, and multipole mixing ratios are presented. The $2_{3}^{+} \rightarrow 2_{1}^{+} 931$ keV and $2_{2}^{+} \rightarrow 2_{1}^{+} 819$ keV transition mixing ratios were re-measured and found to be $\delta = +1.8_{-0.5}^{+0.7}$ and $-1.83(8)$ , respectively. Newly measured mixing ratios for transitions among the low-lying $I^{\pi} = 4^{+}$ states in$^{116}$Sn, when combined with $\gamma$ -ray intensity data, suggest that the 2529 keV $4_{2}^{+}$ state possesses a neutron broken-pair admixture in addition to its dominant proton 2p-2h component