Design proposal for an ionisation chamber as a secondary standard for eye lens dosimetry

We propose a system to directly measure H _p (3) quantity both in calibration conditions at laboratories and at arbitrary conditions at irradiation facilities. A commercial ionisation chamber is inserted in a spherical phantom of PMMA such that the system achieves a relatively constant response in terms of H _p (3) and matches the requirements for a secondary standard for H _p (3) quantity. The H _p (3) ionisation chamber was characterized in a dosimetry calibration laboratory under reference conditions and then, as a proof of concept, it was also tested in a work place field at an interventional cardiology department from a hospital. The design method and the measurement results are presented.