Influence of Li dopants on thermoluminescence spectra of CaSO4 doped with Dy or Tm

► High and low temperature TL spectra of lithium doped CaSO4:Dy or Tm are presented. ► Inclusion of lithium lowers the high temperature glow peak from 200 to 120 °C. ► Defects models involving complexes of lithium and rare earth ions are proposed.