Elsevier Science 1 Si-APD Readout for LaBr 3 :Ce Scintillator Raffaele Scafè a,b,* , Roberto Pani b,c , Rosanna Pellegrini b,c , Giorgia Iurlaro a , Livia Montani a , Maria Nerina Cinti b,c a Casaccia Research Center, ENEA, Rome, Italy b INFN, University of Rome “La Sapienza”, Rome, Italy c Department of Experimental Medicine, University of Rome “La Sapienza”, Rome, Italy Elsevier use only: Received date here; revised date here; accepted date here Abstract In this work we report and compare the results of gamma-ray spectroscopy measurements performed using a LaBr 3 :Ce crystal coupled to a photomultiplier tube with modified base and to a Si-avalanche photodiode readout by standard electronics. Energy resolution values have been obtained in the range from 59.5keV ( 241 Am) to 1332keV ( 60 Co). Good linearity in energy response has been found. Energy resolution values obtained with avalanche photodiode readout are underestimated due to the small active area of the presently available photosensor with respect to crystal dimension. © 2006 Elsevier Science. All rights reserved Keywords: Gamma-ray spectroscopy; Scintillator; LaBr 3 :Ce; Nuclear medicine ——— * Corresponding author: e-mail: scafe@casaccia.enea.it, Ph: +39.06.3048.3434, Fax: +39.06.3048.3989 1. Introduction LaBr 3 :Ce scintillation crystals are attracting the scientific community working on medical radionuclide imaging for potential improvements in PET and SPECT instrumentation, thanks mainly to its good scintillation light output and fast scintillation decay time [1,2]. In particular excellent energy resolution values (3% FWHM at 662keV) can be obtained, due to its high light yield (61000 photons per MeV). First energy resolution measurements performed by Dorenbos et al. coupling crystal samples (from 0.5 to 1 inch diameter) to PMTs showed unexpected worse values than NaI:Tl for Journal logo