Fast-timing capabilities of GRIFFIN

GRIFFIN is the decay spectroscopy facility at TRIUMF-ISAC in Canada. The core of GRIFFIN is an array of 16 large-volume HPGe clover detectors. One of its main features is the variety of ancillary detectors that can be coupled to the main array. SCEPTAR for $\beta$-particle tagging, the 70 liquid scintillators of DESCANT for neutrons or PACES (5 Si(Li) detectors) with high-energy resolution for conversion electrons. A new ancillary array of 8 LaBr$_3$(Ce) detectors for $\gamma$-rays and a fast plastic-scintillator called Zero Degree for $\beta$-particles is optimized for fast-timing experiments with GRIFFIN. The 51 mm x 51 mm cylindrical LaBr$_3$(Ce) crystals are coupled to Hamamatsu R2083 PMT with an integrated pre-amplifier in the PMT base. Timing resolutions as good as FWHM$\sim 300$~ps and time-walks $\pm50$~ps have been obtained using a hybrid analogue and digital DAQ system. electronics. A set of BGO shields minimize the Compton background, one of the main limiting factors in lifetime measurement. The LaBr$_3$(Ce) array has been used in a number of experiments to date, measuring lifetimes down to $\tau\sim 20$~ps. The general fast timing capabilities of GRIFFIN will be presented and some of the measured lifetimes in $^{188-200}$Hg and A=$144-146$ Ba, La and Ce discussed.