Microdosimetric dosemeters for individual monitoring based on semiconductor detectors

The benefit of applying microdosimetric methods to practical radiation protection has been shown with regard to area monitoring. Tissue-equivalent proportional counters are used to measure distributions of energy deposition, which allows the simultaneous determination of absorbed dose and radiation quality in mixed photon and neutron fields. Semiconductor chips are an alternative to proportional counters as active individual dosemeters as they are small in size and very robust. They can be used as microdosimetric detectors for mixed field dosimetry since in memory chips and charged coupled devices (CCD), the radiation sensitive structures have thicknesses of the order of some micrometres. Measurements were performed in a collimated fast neutron beam with commercially available static random access memory (SRAM) chips. Additional tests were performed using a 241Am source. The charge collection capabilities of a modified CCD were studied with simulation calculations. (author)