Comparison of different PADC materials for neutron dosimetry

Investigations on track density and track size distributions of different PADC (poly allyl diglycol carbonate) materials have been performed. The PADC used for the tests has been produced by Thermo Electron (USA), Track Analysis System Limited (UK), Chiyoda Technol Corporation (Japan) and Intercast srl (Italy). For each PADC material 120 detectors were randomly selected out of 2 sheets: 60 detectors from one sheet have been irradiated with a personal dose equivalent of 3 mSv in the field of a 241Am-Be source at the calibration laboratory of PSI, whilst the other 60 detectors from the other sheet have been used as background samples. All detectors have been processed according to an identical etching procedure and have been analysed with TASLImage scanning system. For each set of detectors the value of the average background signal, the average neutron sensitivity and the detection limit with respect to a personal dose equivalent measured with a dosemeter based on PADC have been determined. The results of the investigations allowed a comparison of the neutron sensitivity and background signal behaviours of PADC materials from different manufacturers and the assessment of the variation of neutron sensitivity and background signal over a single sheet. The neutron sensitivity and the background signal of five different commercial available PADC materials were determined using the routine PSI evaluation procedure, including the routine etching procedure, the scanning system and evaluation algorithm of TASL. The differences in sensitivity of the PADC materials to 241Am-Be can be significant and most probably related to the formulation of the material manufacturing process. Although the sensitivities of the five studied PADC materials vary considerably, the lowest detectable dose HLLD remains similar. From the comparison it can be concluded that all studied PADC materials could be used for assessing the personal neutron dose with the routine PSI evaluation procedure, except the material Tech1, which yields a high value for the lowest detectable dose. (authors)