We have been using Personnel TLD for radiation monitoring for the last nine years. The cards are read and annealed on a quarterly basis. I was wondering what is the liftime of TLd cards. The chips we are using are LiF-600 and 700. Your input is very much appreciated. Thanks. Mahmoud S. HAleem KFUPM P.O. box 1061 Dhahran 1061 Saudi Arabia mshaleem@dpc.kfupm.edu.sa