[Radiobiologic basis of the quality factor of protons and helium ions]

Reported data and experimental results of measuring the relative biological effectiveness of protons of different energies and helium ions of 4 GeV/nuclon were analyzed to determine quality factors of the major components of cosmic radiations. It is recommended to use quality factors equal to 1.30-1.45 for 100-730 MeV protons and equal to 1.75 for 9 GeV protons and 4 GeV/nuclon helium ions. It is also suggested to employ them as standards for solving practical problems of radiation safety in space flights.