Exploring the afterglow of GAGG:Ce scintillators for applications in space

The recently developed cerium doped gadolinium aluminum gallium garnet (GAGG) has excellent scintillation properties for radiation detection such that it is suitable for a wide area of basic research and applications. However, the afterglow is a concern for deploying GAGG in space because of the harsh radiation environment. The effects of afterglow of GAGG was studied by irradiating several commercial off-the-shelf samples with a Co-60 source where the accumulated dose is equivalent to the daily average in orbit. The leakage current of the photodiode which was coupled to the scintillator, was measured for an extended period to examine the afterglow from the exposure. Because not all traps in the GAGG samples were filled up in one instance and the lower gain of the photodiode, the leakage current quickly decreased back to the baseline. It is concluded that the effects of GAGG’s afterglow due to cosmic radiation in orbit is manageable and can be mitigated by using photodiode as the readout device.