Development of a LaBr₃(Ce) Fast-timing Array for FAIR

¹ School of Computing, Engineering and Mathematics, University of Brighton, Brighton, BN2 4GJ, U.K
² Department of Physics, University of Surrey, Guildford, GU2 7XH, U.K
³ National Physical Laboratory, Teddington, TW11 0LW, U.K
⁴ University of Manchester, Oxford Road, Manchester, M13 9PL, U.K
⁵ Nuclear Physics Research Group, University of the West of Scotland, Paisley, PA1 2BE, U.K

^a e-mail: O.J.Roberts@brighton.ac.uk

Published online: 19 December 2013

Abstract

A γ-ray spectrometer with fast-timing capabilities, constructed of LaBr3(Ce:5%) detectors, is under development for use at the future Facility for Anti-proton and Ion Research (FAIR). The physics aims of this device are to measure the half-lives of excited states in the region of ~50 ps to several ns, in exotic nuclei. Monte-Carlo simulations using the GEANT4 software package have determined the final design of this fast-timing array by calculating the full-energy peak efficiencies of several different detector geometries. The results of the simulated efficiencies for each configuration were used to calculate the timing precision. Consequently, an array of thirty six, ø3.8×5.1 cm cylindrical crystals was found to be the optimum configuration. The detectors were purchased and subsequently characterised, with each detector found to have intrinsic energy and timing resolutions of ~ 2.8 % (FWHM) and ~ 210 ps (FWHM) for the 1173 and 1332 keV decays from ⁶⁰Co.