Thermoluminescence in calcium borate containing copper

In a previous paper we reported on the thermoluminescence (TL) of borate glass containing copper. It showed a prominent glow peak at about 110 deg C. However, it was not suitable for radiation dosimetry. Meantime, Takenaga et al. reported that a lithium borate phosphor containing copper prepared by sintering showed an intense TL peak at 205 deg C. Their results seem to indicate that borates prepared by sintering give strong TL responses at relatively high temperature regions. The following study is undertaken with the hope that some other borates may show more suitable TL responses that may be used for dosimetry when they are properly arranged. We have prepared four different samples: sintered CaB4O7 (a) with and (b) without copper, and glassy CaB4O7 (c) with and (d) without copper. For the sake of comparison we also used the borate glass containing copper previously reported. Experimental details are given. Figures show the glow curves for each type of sample (with various amounts of copper, and x-irradiated to various doses) and emission spectra of TL peaks at various temperatures. The results are discussed. (author)