Correction factors kE and kQ for LiF-TLDs for dosimetry in megavoltage electron and photon beams.

For the determination of absorbed dose to water D,using thermolumeniscence (TL) probes in a beam different from that used for calibration, correction factors for radiation type and radiation quality kE and kQ are needed. Values for kE and kQ for two different shapes of LiF probes (rods and disks) were obtained for high-energy photon and electron beams. The relation between the absorbed dose to the medium (water) D, measured by ion-chambers according to DIN 6800-2, 2008 and TL-probes having a (60)Co-calibration factor, leads for each shape and each batch of LiF probes to correction factors for radiation type and radiation quality kE and kQ.. The influence of the shape on the correction factor of the probes amounts in our experiment up to 2%. Therefore, it is recommended that the correction factors kE and kQ for rods and disks should be checked for each batch of LiF-detectors.