Medical Physics Seminar – Monday, April 22, 2013
Revisiting an old idea - application of the Fricke dosimeter in primary standards
Malcolm McEwen (guest of Dr. Larry DeWerd)
The Fricke chemical dosimeter dates from the 1920s and over recent decades its use has fallen off sharply, viewed as “old-fashioned†and often replaced by simpler integrating dosimeters. However, it still offers several advantages over all other chemical dosimeters, including: i) a ‘universal’ radiation chemical yield that means batch or sample-specific calibration is not required, and ii) packaging in an arbitrary volume. With the correct preparation and readout protocol an uncertainty approaching that achievable with ionization chambers is possible and this, combined with the development of ‘wall-less’ holders (pioneered at METAS, the Swiss standards laboratory), opens up new avenues of investigation. This talk will highlight the recent uses to which Fricke dosimetry is being put in the development of primary dosimetry standards at the National Research Council.