THERMOLUMINESCENCE PROPERTIES OF LIF(MG,CU,P) WITH DIFFERENT COPPER CONCENTRATIONS

TL emission characteristics have been studied from LiF(Mg,Cu,P) sample s prepared at the Institute of Nuclear Physics in Krakow, Poland in wh ich the Cu concentration has been varied from 0.002 mol% to 0.5 mol% w hile the Mg content (0.2 mol%) and P content (1.25 mol%) were kept con stant. Thermoluminescence has been recorded both as function of temper ature and wavelength and absorption spectra were derived from diffuse reflectance measurements. The TL response of main dosimetry peak 4 inc reases with increasing Cu concentration up to 0.02 mol% and decreases for higher Cu content. With increasing Cu concentration the high tempe rature TL decreases. The emission spectra can be described with two ov erlapping emission bands peaking at 352 nm and 387 nm. The ratio of th e intensities of both emission bands alters with temperature and Cu co ncentration. The high temperature thermoluminescence shows more 352 nm emission. No unique role of copper as trapping or as luminescent cent re could be derived. Copper appears to play an indirect role in the tr apping of charge carriers, possibly reducing the occurrence of higher order Mg defects and/or the improvement of the efficiency of the lumin escent centre.