Red 4034 perspex dosimeters in industrial radiation sterilization process control

Red 4034 Perspex Dosimeters, by virtue of their availability in large single batch quantities and relative simplicity of use, are widely applied for routine monitoring and control of radiation processes. In the course of the use of tens of thousands of these dosimeters representing five different batches, several factors have been identified which affect their precision, accuracy, and reliability. The variability in response characteristics among batches and lots within batches has been documented. It has also been found that in some cases the response characteristic for a given batch or between lots within a batch differs significantly from those published by the manufacturer. These differences have been linked to the effects of moisture content. The effects on dose interpretation due to physical dimensional differences between individual dosimeters are discussed. Sample procedures are presented for achieving tolerance limits of +- 0.07 megarads on averages of duplicate measurements in the range of 2 to 3 Mrad. The efficacy of these procedures is documented by an analysis of a thousand consecutive sequential measurements in an industrial irradiation facility. (author)