The GRIFFIN facility for Decay-Spectroscopy studies at TRIUMF-ISAC

Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei, GRIFFIN, is a new high-efficiency γ-ray spectrometer designed for use in decay spectroscopy experiments with low-energy radioactive ion beams provided by TRIUMF\u27s Isotope Separator and Accelerator (ISAC-I) facility. GRIFFIN is composed of sixteen Compton-suppressed large-volume clover-type high-purity germanium (HPGe) γ-ray detectors combined with a suite of ancillary detection systems and coupled to a custom digital data acquisition system. The infrastructure and detectors of the spectrometer as well as the performance characteristics and the analysis techniques applied to the experimental data are described

High-precision half-life and branching ratio measurements for superallowed β\u3csup\u3e+\u3c/sup\u3e Emitters At TRIUMF-ISAC

High precision measurements of the ft values for superallowed Fermi β transitions between Jπ = 0+ isobaric analogue states allow for stringent tests of the electroweak interaction described by the Standard Model. These transitions provide an experimental probe of the Conserved-Vector-Current hypothesis, enable the most precise determination of the up-down (Vud) element of the Cabibbo-Kobayashi-Maskawa quark-mixing matrix, and allow one to set stringent limits on the existence of scalar currents in the weak interaction. An extensive program of superallowed branching-ratio and half-life measurements at TRIUMF\u27s Isotope Separator and Accelerator (ISAC) facility has covered the full range of superallowed emitters, from the lightest case, 10C, to the heaviest case for which precision data are currently available, 74Rb. These experiments have been performed using a 4π continuous-flow gas proportional β counter, the 8π γ-ray spectrometer, and, most recently, the new high-efficiency GRIFFIN γ-ray spectrometer. In this paper, recent highlights from the superallowed Fermi β decay program at TRIUMF will be summarized, including high-precision half-life measurements for all three of the lightest superallowed emitters, 10C, 14O, and 18Ne, with the greatest sensitivity to a potential weak scalar current contribution, as well as high-precision branching-ratio measurements for the heavy superallowed emitters 62Ga and 74Rb

New Opportunities in Decay Spectroscopy with the GRIFFIN and DESCANT Arrays

AbstractThe GRIFFIN (Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei) project is a major upgrade of the decay spectroscopy capabilities at TRIUMF-ISAC. GRIFFIN will replace the 8π spectrometer with an array of up to 16 large-volume HPGe clover detectors and use a state-of-the-art digital data acquisition system. The existing ancillary detector systems that had been developed for 8π, such as the SCEPTAR array for β-tagging, PACES for high-resolution internal conversion electron spectroscopy, and the DANTE array of LaBr3/BaF2 scintillators for fast γ-ray timing, will be used with GRIFFIN. GRIFFIN can also accommodate the new neutron detector array DESCANT (Deuterated Scintillator Array for Neutron Tagging), enabling the study of β-delayed neutron emitters. DESCANT consists of up to 70 detectors, each filled with approximately 2 liters of deuterated benzene, a liquid scintillator that provides pulse-shape discrimination (PSD) capabilities to distinguish between neutrons and γ-rays interacting with the detector. In addition, the anisotropic nature of n-d scattering as compared to the isotropic n-p scattering allows for the determination of the neutron energy spectrum directly from the pulse-height spectrum, complementing the time-of-flight (TOF) information. The installation of GRIFFIN is under way and first experiments are planned for the fall of 2014. The array will be completed in 2015 with the full complement of 16 clovers. DESCANT will be tested coupled with GRIFFIN in spring of 2015

High-precision Half-life And Branching Ratio Measurements For Superallowed β+\beta^+ Emitters At TRIUMF-ISAC

International audienceHigh precision measurements of the ft values for superallowed Fermi β transitions between J π = 0 + isobaric analogue states allow for stringent tests of the electroweak interaction described by the Standard Model. These transitions provide an experimental probe of the ConservedVector-Current hypothesis, enable the most precise determination of the up-down (Vud) element of the Cabibbo-Kobayashi-Maskawa quark-mixing matrix, and allow one to set stringent limits on the existence of scalar currents in the weak interaction. An extensive program of superallowed branching-ratio and half-life measurements at TRIUMF’s Isotope Separator and Accelerator (ISAC) facility has covered the full range of superallowed emitters, from the lightest case, 10C, to the heaviest case for which precision data are currently available, 74Rb. These experiments have been performed using a 4π continuous-flow gas proportional β counter, the 8π γ-ray spectrometer, and, most recently, the new high-efficiency GRIFFIN γ-ray spectrometer. In this paper, recent highlights from the superallowed Fermi β decay program at TRIUMF will be summarized, including high-precision half-life measurements for all three of the lightest superallowed emitters, 10C, 14O, and 18Ne, with the greatest sensitivity to a potential weak scalar current contribution, as well as high-precision branching-ratio measurements for the heavy superallowed emitters 62Ga and 74Rb