AUTHOR=Aldawood Saad , Castelhano Ines , Gernhäuser Roman , Van Der Kolff Hugh , Lang Christian , Liprandi Silvia , Lutter Rudolf , Maier Ludwig , Marinšek Tim , Schaart Dennis R. , Parodi Katia , Thirolf Peter G. TITLE=Comparative Characterization Study of a LaBr3(Ce) Scintillation Crystal in Two Surface Wrapping Scenarios: Absorptive and Reflective JOURNAL=Frontiers in Oncology VOLUME=5 YEAR=2015 URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2015.00270 DOI=10.3389/fonc.2015.00270 ISSN=2234-943X ABSTRACT=

The properties of a 50 mm × 50 mm × 30 mm monolithic LaBr3:Ce scintillator crystal coupled to a position-sensitive multi-anode photomultiplier (PMT, Hamamatsu H9500), representing the absorbing detector of a Compton camera under study for online ion (proton) beam range verification in hadron therapy, was evaluated in combination with either absorptive or reflective crystal surface coating. This study covered an assessment of the energy and position-dependent energy resolution, exhibiting a factor of 2.5–3.5 improvement for the reflectively wrapped crystal at 662 keV. The spatial dependency was investigated using a collimated 137Cs source, showing a steep degradation of the energy resolution at the edges and corners of the absorptively wrapped crystal. Furthermore, the time resolution was determined to be 273 ps (FWHM) and 536 ps (FWHM) with reflective and absorptive coating, respectively, using a 60Co source. In contrast, the light spread function (LSF) of the light amplitude distribution on the PMT segments improved for the absorptively wrapped detector. Both wrapping modalities showed almost no differences in the energy-dependent photopeak detection efficiency.