Performance evaluation of thermoluminescent cards using nitrogen generator in comparison with commercial nitrogen and compressed air

Performance of the TLD cards is evaluated from the dose point of view by heating them under three different conditions viz. nitrogen from nitrogen generator, nitrogen from commercial nitrogen cylinders and compressed air cylinder and the results are compared with true dose. To begin with, the background reading and its standard deviation are found to be more for those cards read by using compressed air compared to nitrogen generator. About 100 cards were used for comparison for the first cycle. Out of this, a total of 30 cards were subjected to 10 test cycles. It is observed that the performance of the cards before and after 10 test cycles does not vary much. The maximum deviation observed is about ±8% from the true dose. (author)