Monitoring of onboard aircraft exposure to cosmic radiation: May–December 2005

Onboard aircraft exposure to cosmic radiation has been monitored during the period May–December 2005. Mobile Dosimetry Unit (MDU) Si-spectrodosimeter has been used as an active measuring equipment, it has been installed onboard of an A310–300 aircraft. Some passive detectors were placed on the body of MDU. Three types of thermoluminescent detectors (TLD) were used as well as track etch detectors (TEDs). TEDs were treated both as a neutron dosimeter and as a spectrometer of linear energy transfer. Available navigation data permitted us also to calculate onboard exposure during more than 400 individual flights. MDU established and calculated data for each individual flight are compared and analyzed, from the data conclusions as to aircrew exposure are outlined. Particular attention is devoted to the influence of: • geomagnetic characteristics and flight altitude on the calculated and MDU-Liulin measured dosimetry characteristic of onboard radiation field; • some solar events (Forbush decreases) registered by MDU-Liulin on the level of aircraft crew exposure during monitoring period. Integral data on the exposure due to non-neutron and neutron-like component obtained on the base of MDU and calculated data are compared with the data obtained by TLDs and TEDs, respectively. Total effective dose during the period mentioned (494 flights and 2940 h between taking offs and landings) was found to be about 11–12 mSv for. Results obtained by means of different approaches are analyzed and discussed, it was found that in general good agreement of all data sets could be stated.