The scintillator is the primary radiation sensor that emits light when struck by high energy photons.
There are two main disadvantages to this scintillator; one being the hexagonal crystal structure, which emits only optical translucency and low external light collection at the photodiode.
It is also used as a green phosphor in projection CRTs, though its drawback is marked lowering of efficiency at higher temperatures.
The crystal structure of gadolinium oxysulfide has Trigonal symmetry (space group number 164).
[4] An approved respirator should be worn if exposure to dust could occur when working with gadolinium oxysulfide.
Gadolinium oxysulfide should be stored away from mineral acids, strong oxidizers and flammable materials.