Beta radiation dosimetry with electrets

Cylindrical electret ion-chambers were used for detection and dosimetry of beta radiation and showed a linear decrease of electret charge with absorbed dose for different field geometries and wall materials. A beta secondary standard system was used with four beta sources (⁹⁰Sr⁻⁹⁰Y, ²⁰⁴TL, ¹⁴⁷Pm and ⁸⁵Kr). Doses from 10⁻⁶ Gy to 10⁻¹Gy can be measured with the system.