ESR Dosimetry of cow teeth from South Ural region

Abstract

Since it was found that tooth enamel is an excellent material for ESR (electron spin resonance) retrospective dosimetry, many studies have used human teeth for estimating doses of radiation accidents. However, human teeth are not always available for retrospective individual dose assessment. In such situations teeth from animals could be used as alternative to human teeth for retrospective dosimetry.The conditions for chemical treatment suitable for extracting enamel from cow teeth were investigated. It is essentially important to remove dentin from tooth enamel for low dose radiation dosimetry in order to avoid interfering ESR signal due to organic radicals. We found that 20% of NaOH and KOH for 5 hours at 40C give the best S/N ratio in ESR spectra.Using this technique, the doses given to cow teeth from the South Ural region, Russia, were investigated, part of which were contaminated by the accidents at the first Russian industrial nuclear facility, Mayak. The doses of most of the teeth were less than the detection limit, but doses up to 200 mGy were obtained from some of the teeth which contain up to 10 Bq/g of 90Sr.