Modified Liulin detector calibration for onboard aircraft dosimetry measurements

During their careers, aircraft crews are exposed to cosmic radiation more than people on the Earth's surface. Therefore, the exposure of aircraft crew to cosmic radiation is considered as occupational exposure in all EU member states, and even some non-EU countries. Routine dosimetry of aircraft crew is performed using computer programs based mainly on Monte Carlo simulations. Onboard dosimetry measurements are important for verification of the computational methods and for research. One of the detectors used for characterization of the radiation field onboard aircraft is active semiconductor detector Liulin originally developed for monitoring of cosmic radiation at the MIR space station. The output quantity of the measurement with the Liulin detector is the ambient dose equivalent H^*(10) calculated with use of the absorbed dose D. This requires two calibrations. The purpose of our work was to develop one of these calibration methodologies converting the detector signal to the absorbed dose D independently of calibration performed at HIMAC facility in Chiba. The new calibration method is based on standard alpha radionuclide sources and replacement of the original PIN diode type S2744-08 with epoxy layer for the diode type S2744-09 without protective resin layer. The work reaches its conclusion by comparing the DSi results of Prague-Moscow flight, measured both by the Liulin detector with an original diode and standard calibration and the newly calibrated Liulin detector with the replaced diode. (authors)