A Secondary Standard Ionisation Chamber for the Direct Measurement of Ambient Dose Equivalent H*(10)

Abstract

In 1985 ICRU devised new phantom2-1related dose equivalent quantities for radiation protection practice which are being implemented in various countries. Up to now calibration of monitoring equipment used to measure these quantities could only be performed indirectly using energy dependent conversion factors from the old quantities exposure or air kerma. A secondary standard ionisation chamber has been developed which, with adequate uncertainty, provides a direct measurement of ambient dose equivalent H*(10) for photon radiation in the range from 40 keV to 1.3 MeV, independent of the actual energy spectra