Question

why the existence of electron trapping sites in a crystalline material is desirable if the material is used as a thermoluminescent dosimeter, but undesirable if the material is used as a conventional scintillator

Answer 1

Thermoluminescent dosimeter (TLD) is a passive radiation detection device that is used for personal dose monitoring or to measure patient dose. Materials exhibiting thermoluminescence in response to ionizing radiation. The ionizing radiation will be active when the existence of electron trapping sites in a crystalline material. But the electron trapping sites are not useful in conventional scintillator because a scintillation detector or scintillation counter is obtained when a scintillator is coupled to an electronic light sensor such as a photomultiplier tube (PMT), photodiode, or silicon photomultiplier.