Studies of the effect of LET on the thermoluminescent properties of thin lithium fluoride layers

A requirement to develop thin dosemeters with adequate sensitivity for specific applications to mixed field measurements has led to an assessment of 20 μm thick lithium fluoride particles on polymide discs using thermoluminescence measurements and radiations of different LET. The results of this study indicate that these thin discs, which are inexpensive and uncomplicated to manufacture, have potential for practical applications over a limited dose range. The following effects have been observed: (1) The thermoluminescent response per unit mass is a sensitive function of dose and LET. For doses below 380 rad, the response ratio of high LET alpha response to low LET gamma response is about 0.3. (2) 6LiF and 7LiF can be used to discriminate between radiation of different LET from either the response or the peak height ratio of peak 6 to peak 5. The exact nature of the effect requires further investigation, but this ratio is low for low LET irradiated 6LiF and high for high LET irradiated material. The ratio remains LET invariant in 7LiF. (author)