Intercomparison between CaF2 - based environmental TLDs and newly modified CaSO4: Dy TLDs

In an intercomparison exercise that was carried out by deploying the CaF2 based environmental TLDs and CaSO4:Dy based personnel monitoring TLDs for assessing the suitability of the later in indoor dosimetry in Monazite bearing areas in Kerala (Shetty et al, 2004) it was observed that in the case of CaSO4.Dy based personnel monitoring TLDs uncertainties would be large when doses are below about 250 μGy. The CaSO4:Dy based TLDs were therefore modified to increase the sensitivity and make it suitable for environmental radiation monitoring. The modified TLDs were deployed at thirty seven locations for the period of about three months. The analysis of two such cycles indicates that the modified TLDs perform well in comparison with the CaF2 based TLDs. The paper discusses the design parameters and the results of the comparison studies. (author)