A mobile TEPC-based system to measure the contributions to H*(10) at flight altitudes.

A very promising method to measure the ambient dose equivalent H*(10) at flight altitudes is to use Tissue Equivalent Proportional Counters (TEPC). The measured quantity is the lineal energy, y, which can be converted into equivalent dose as a good estimate of H*(10). According to the lineal energy transfer (LET) spectra one may even extract information about the composition of the radiation field. A new system was developed by adding a surrounding coincidence detector (CACS: Coincidence/Anti-Coincidence Shield) that allows one to identify the primary particle, which deposits energy in the TEPC, as neutral or charged. The entire system was calibrated in the neutron and high-energy photon reference fields at PTB. One of the results of these measurements is, the use of low- and high-LET calibration factors when performing measurements in mixed radiation fields. The TEPC/CACS system is now operated on-board aircrafts as a fixed or mobile dosimetry system.