Linearity measurement of next generation scintillatorGAGG at high energies using the 992KeV resonance of the 27Al(p,γ)28Sireaction

Scintillator detectors provide a very large efficiency for the detection of γ-ray in nuclear physics experiments. However due to the non-linear light output of the crystals, the extrapolation of the calibration parameters obtained using standard sources is not reliable at high energies. A new scintillator, cerium-doped Gd3Al2Ga3O12(GAGG) was recently developed. It has a large effective Z, thus expected to have high peak-to-total ratio and efficiency. The primary purpose of this experiment is to evaluate the linearity of the GAGG light output for high energy γ-rays. To produce these high energy γ-rays, the 27Al(p,γ)28Si reaction was used. This reaction produces a number of γ-ray transitions up to 10 MeV. The experiment was performed at RIKEN Pelletron, which provides proton beams up to 3MeV. Four GAGG crystals with different geometries, and 9 DALI2 crystals were arranged around a 27Al target. Different combinations of photomultipliers and GAGG detector geometries were used. Using standard calibration source, and the γ-ray transitions from resonances in 28Si up to 10 MeV, the linearity of GAGG detectors were characterized. The linearity of DALI2 was also characterized for the first time. Here we show the first results on the performance of GAGG as a detector for high-energy γ-rays.