Preliminary investigation of scintillator materials properties: SrI2:Eu, CeBr3 and GYGAG:Ce for gamma rays up to 9 MeV

In this work we measured the performance of a 2″×2″ cylindrical tapered crystal of SrI2:Eu, a 2″×3″ cylindrical sample of CeBr3 and a 2″×0.3″ 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 Nucléaire dOrsay. 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 137Cs 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 88Y source. The signals of the detectors were additionally digitized and compared, up to 9 MeV, using a 12 bit LeCroy 600 MHz oscilloscope.