HDR microSelectron quality-assurance studies using a well-type ion chamber

Abstract

A modified Standard Imaging HDR 1000 re-entrant ion chamber has been used with an NE 2570/1 electrometer as part of a quality-assurance programme for checking 192Ir source strengths and for source localization studies. The chamber measurements correlate well with in-air calibration measurements made over a three-month source-decay period; the maximum discrepancy between the in-air measurement and the re-entrant chamber measurement was 0.9%. The source position may be determined with an uncertainty of lower than 0.5 mm. The reproducibility of measurements made with each of four electrometers used with the re-entrant ion chamber was typically 0.1% (1 sigma ).