Modification of beta dose evaluation algorithm for better accuracy in personnel monitoring

Dose due to beta radiations is the main contributor to the skin dose. Assessment of individual dose (whole body, skin, extremity) in India is based on CaSO₄:Dy based Teflon embedded TLD badge used for personnel monitoring. The design of the dosemeter enables identification of radiation type which, in turn, allows use of radiation specific algorithm for dose evaluation. The difference of response of three discs of the TLD badge to beta radiation in beta/beta-gamma fields is due to the presence of different filters corresponding to the three discs. The response of disc under metal filter (D₁) to beta being negligible while that of open disc (D₃) is the maximum. The ratio of response of open disc to that under Perspex (D₃/D₂) to beta is highly dependent on its energy and angle of incidence. Therefore estimation of dose due to beta is based on response of open disc corrected for the energy of beta using D₃/D₂