The design philosophy for an automatic TLD system to meet current international specifications

The object of this paper is to describe the elements of a new automatic TLD system intended to meet draft IEC/ISO proposals and ANSI requirements in the USA. Dosemeter badge design is based on ICRU recommendations. The basic intent has been to produce a standard system that can measure and file raw data that can be adapted to specific user requirements with software. The system consists of a programmable automatic reader, an automatic irradiator, a computer, and dosemeters for environmental, whole body, extremity, and clinical applications. The reader uses hot nitrogen heating and photon counting, and measurement conditions may be chosen with complete freedom. The reader can produce a real-time glow curve to assist in checking performance. The irradiator has a 90Sr-90Y source to permit programmed irradiation for calibration and material sensitivity checks. Cassettes are used to hold TLD cards during processing. Cassette coding both identifies samples and calls measurement parameters into use from memory. The system can be preprogrammed to measure all common materials and all common dosemeter elements (both square and round). (author)