OPTICAL AND THERMOLUMINESCENCE PROPERTIES OF LIF-CU, LIF-MG,CU AND LIF-MG,CU,P SINGLE-CRYSTALS

Thermoluminescence properties and optical absorption in the UV-VIS reg ion (1.5-6.5 eV) during linear heating from RT up to 400 degrees C of in-house grown LiF:Mg, LiF:Mg,Cu and LiF:Mg,Cu,P single crystals were investigated. TL glow curve and emission spectrum (not sensitivity) of the LiF:Mg,Cu,P single crystals are the same as for the highly sensit ive detectors of the optically non-transparent GR-200 type. The absorp tion spectra of the LiF:Mg,Cu and LiF:Mg,Cu,P crystals are practically the same in 1.5-6.0 eV region at temperatures from RT to 200 degrees C. The presence of Cu exhibits itself in the high energy region of the spectrum where a ''tail'' of some vacuum ultraviolet band has been ob served. The difference between the crystals doped with Mg and Cu and M g, Cu and P on the one hand and those doped with only Mg on the other is mainly in the different decay of the radiation induced bands above 200 degrees C. In the Mg,Cu and Mg,Cu,P crystals the 4.5 and 5.0 eV ba nds decay simultaneously with the 4.0 eV band. Above 250 degrees C at 5.5 eV band starts growing in only Mg doped crystals. At higher temper atures this band decays at approximately the same rate as the 4.0 and 4.5 eV bands. The 5.5 eV band is not noticed in the other crystals. Th e temperatures of steep decay of the bands shift to low temperatures i n the order of Mg, (Mg,Cu), (Mg,Cu,P). (C) 1998 Elsevier Science Ltd. All rights reserved.