LaBr3(Ce):LaCl3(Ce) Phoswich with pulse shape analysis for high energy gamma-ray and proton identification

A novel Phoswich design based on new generation scintillator crystals is presented. The detector composed from a combination of a LaBr3LaBr3(Ce) with a LaCl3LaCl3(Ce) crystal in one cylinder coupled to a photo multiplier tube has been tested both for incident gamma rays in the range of 0.3–6 MeV, as well as for high energy protons in the range 120–180 MeV. The Phoswich assembly has not significantly deteriorated the energy resolution, which for 662 KeV gamma rays gives a resolution of 4.5%, while for high energy protons (EpEp=180 MeV) an energy resolution of 1% was obtained. It is shown that the signals from the two crystals can be separated in an event by event based mode. Using direct digitizing of the detector pulse an off-line pulse-shape analysis was performed built either on a total to tail or total to pulse height method in order to fully identify the incoming radiation. Our aim with this R&D is to in the future build a detector which is able to detect with good efficiency and resolution over a wide energy range; 0.1–30 MeV gamma rays and 20–400 MeV protons. Monte Carlo simulations made in order to design the next prototype are presented.