B. Olaizola

Assessment of new photosensors for fast timing applications with large scintillator detectors

The measurement of absolute nuclear transition probabilities is a very sensitive tool to study the structure of the atomic nucleus. Direct access to transition rates can be achieved via the lifetime of the nuclear levels de-populated in radioactive decay. The Advanced Time-Delayed (ATD) method, or Fast Timing, is a well-established technique to measure lifetimes down to a few ps. The development of the technique was based on the use of BaF2 detectors, but a recent major breakthrough occurred with the introduction of LaBr3(Ce) crystals, uniting excellent time response with much superior energy resolution than BaF2 crystals. Relatively large LaBr3(Ce) cylindrical detectors of typically 1.5″×1.5″ are employed for fast timing, in combination with fast 2-inch photomultiplier tubes from Photonis such as the linear focused 8-stage XP20D0. Another option for a 2-inch fast phototube is the 8-stage Hamamatsu R9779, whose timing properties have already been tested with small LSO crystals. New possibilities are also offered by novel photosensors such as silicon photomultipliers, which are intrinsically fast. In this work we have investigated the performance of the Hamamatsu R9779 photomultiplier tube, and the viability of CeBr3 crystals for fast-timing applications.

Spectroscopy of

The GRIFFIN spectrometer at TRIUMF-ISAC has been used to study excited states and transitions in

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Sc and ab initio calculations of B(M3) strengths

Sc following the

High-precision half-life measurement for the superallowed Fermi β+ emitter Mg22

\beta

Fast Timing Study of the β− Decay of 63Mn to 63Fe

-decay of

Fast-Timing Study in the 78Ni Region: β-Decay of 81Zn

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Low-lying isomeric states inGa80from theβ−decay ofZn80

Ca. Branching ratios were determined from the measured

Structure of [sup 81]Ga populated from the β− decay of [sup 81]Zn

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Structure of 81Ga populated from the β− decay of 81Zn

-ray intensities, and angular correlations of