Development and validation of reference workpieces for determining the active volume of ionization chambers

Abstract

The article presents the development and validation of reference workpieces for determining active volume of ionization chambers used in radiation dosimetry. Accurate determination of active volume is essential for precise measurements of absorbed dose in radiotherapy and radiation protection. Therefore, sixteen reference sets made of graphite and PA6 aluminium alloy, featuring different geometries and nominal volumes, were designed and manufactured. The volumes of the reference sets were determined based on high-precision coordinate measurements of their geometric features. Measurements were conducted independently in two laboratories to ensure verification and comparability of the results. Measurement uncertainties were evaluated using the sensitivity analysis method. The obtained expanded uncertainties met the stringent requirements for reference standards in metrology. Good agreement between the results obtained in both laboratories was confirmed using conformity assessment criteria. The developed reference sets can be used for calibration and validation of X-ray computed tomography methods in dimensional metrology.