Natural, Fused Quartz - Scintillator Crystals

I'm looking for a scintillator crystal for ion beam imaging device (proton, Carbon and Oygen ) with Intensities going up to 20 mA. I saw different type of quartz : natural quartz, fused silica also float quartz. Can somebody explain me the difference ? From what I know; Natural quarts is weaker than fused quartz but I don't really know why. ?

I 'm also looking at transparent crystals doped and undoped such as doped sapphire, YAG, doped CsI … Normally it looks like doped crystals should be more efficient and also damage resistant which is not the case. Sometimes undoped materials are more suitable. Why?

It looks like Transparent Scintillator Crystals form two groups : the Alkali halide crystals and the Inorganic Non Alkali halide crystals. What are the different properties of these two types with respect to Light output and radiation damage ?

Thanks