Preliminary investigation of scintillator materials properties: SrI 2 :Eu, CeBr 3 and GYGAG:Ce for gamma rays up to 9 MeV

In this work we measured the performance of a 2ʺ×2ʺ cylindrical tapered crystal of SrI 2 :Eu, a 2ʺ×3ʺ cylindrical sample of CeBr 3 and a 2ʺ×0.3ʺ cylindrical sample of GYGAG:Ce. These scintillators are prototypes in volume or material and were provided by the Lawrence Livermore National Laboratory and by the Institut de Physique Nucleaire d׳Orsay. The gamma-ray energy resolution was measured in the energy range of 0.1–9 MeV using different sources. Each scintillator was scanned along x , y and z axes, using a 400 MBq collimated 137 Cs source. Owing to the GYGAG:Ce thickness, it was not possible to obtain the value of the energy resolution at 9 MeV and to scan the crystal along the z axis. The 662 keV full energy peak position and its FWHM were measured relative to the full energy peaks positions produced by a non-collimated 88 Y source. The signals of the detectors were additionally digitized and compared, up to 9 MeV, using a 12 bit LeCroy 600 MHz oscilloscope.