Reliability, calibration and metrology in ionizing radiation dosimetry

TL;DR

This paper examines the reliability, calibration, and measurement accuracy of ionizing radiation dosimetry systems, emphasizing thermoluminescent dosimeters, and discusses statistical errors affecting dosimetry performance.

Contribution

It provides a comprehensive systems analysis of radiation dosimetry, highlighting the impact of calibration, drift noise, and statistical errors on dosimeter reliability and accuracy.

Findings

Most sensitivity decrement is due to drift noise, not actual degradation.

Proper calibration compensates for performance decrements in dosimeters.

Addressing statistical errors improves dosimetry system accuracy.

Abstract

Radiation dosimetry systems are complex systems, comprised of a milieu of components, designed for determining absorbed dose after exposure to ionizing radiation. Although many materials serve as absorbing media for measurement, thermoluminescent dosimeters represent some of the more desirable materials available; yet, reliability studies have revealed a clear and definite decrement in dosimeter sensitivity after repeated use. Unfortunately, repeated use of any such material for absorbing media in ionizing radiation dosimetry will in time experience performance decrements; thus, in order to achieve the most accuracy and/or precision in dosimetry, it is imperative proper compensation be made in calibration. Yet, analysis proves the majority of the measured decrement in sensitivity experienced by dosimeters is attributable to drift noise and not to any degradation in dosimeter performance, at least, not to any great degree. In addition to investigating dosimeter reliability, implications for metrological traceability and influences for calibration, this monograph addresses certain errors in applied statistics, which are rather alarming habits found in common usage throughout the radiation dosimetry community. This monograph can also be considered a systems analysis of sorts; because, attention to such key topics, so general and essential in nature, produces an effective system analysis, where each principle covered aptly applies to radiation dosimetry systems in general.