Extensive study of radiation dose on human body at aviation altitude through Monte Carlo simulation.

The diverse near-Earth radiation environment due to cosmic rays and solar radiation has direct impact on human civilization. In the present and upcoming era of increasing air transfer, it is important to have precise idea of radiation dose effects on human body during air travel. Here, we calculate the radiation dose on the human body at the aviation altitude, also considering the shielding effect of the aircraft structure, using Monte Carlo simulation technique based on Geant4 toolkit. We consider proper 3D mathematical model of the atmosphere and geomagnetic field, updated profile of the incoming particle flux due to cosmic rays and appropriate physics processes. We use quasi-realistic computational phantoms to replicate the human body (male/female) for the effective dose calculation and develop a simplified mathematical model of the aircraft (taking Boeing 777-200LR as reference) for the shielding study. We simulate the radiation environment at the flying altitude (at 10 km and considering geomagnetic latitude in the range of 45-50°), as well as at various locations inside the fuselage of the aircraft. Then, we calculate the dose rates in the different organs for both male and female phantoms, based on latest recommendations of International Commission on Radio logical Protection. This calculation shows that the sex-averaged effective dose rate in human phantom is 5.46 μSv/h, whereas, if we calculate weighted sum of equivalent dose contributions separately in female and male body: total weighted sum of equivalent dose rate received by the female phantom is 5.72 μSv/h and that by the male phantom is 5.20 μSv/h. From the simulation, we also calculate the numerous cosmogenic radionuclides produced inside the phantoms through activation or spallation processes which may induce long-term biological effects.