Studies on the retrospective thoron measurements by CDs/DVDs: A posteriori calibration and influence of environmental factors
Résumé
Past exposure to indoor thoron poses a significant risk for lung cancer. A method based on home-stored CDs/DVDs allows the estimation of past exposure through retrospective thoron measurements. However, these measurements are significantly affected by the geometry of the CD-case. In this paper, an improved a posteriori calibration procedure is proposed that mitigates the CD-case effect, enabling the estimation of the disk's calibration factor with uncertainty better than 20%. The influence of the environmental temperature, pressure and humidity on the thoron measurements is also studied. It is observed that these parameters have influence within 30%. Thus, retrospective thoron measurements with uncertainty better than 50% can be conducted. The CD method overcomes a major source of error in evaluating the past thoron exposure related to the yearly changes in indoor thoron that could even reach an order of magnitude.