Charge carrier trapping and thermoluminescence in calcium fluoride based phosphors

Abstract This paper reviews recent progress in the understanding and applications of the phenomenon of thermoluminescence (TL) in calcium fluoride based phosphors. The formation of charge carrier traps in rare earth and Mn doped CaF 2 and the effects of dose and the LET of radiation on the glow curve are discussed. The dosimetric properties and applications of the popular materials like CaF 2 :Tm, CaF 2 :Mn and CaF 2 :Dy are also described. The various explanations for the TL phenomenon in these materials are given to highlight the complications and difficulties in completely understanding the mechanisms involved. Optical absorption, ESR, electrical relaxation studies and detailed analysis of the TL emission spectrum lead to the identification of some charge carrier traps and luminescent centres, but one-to-one trap/luminescent centre correlation is very difficult.