Raditaion dose received by Astronauts in space

Radiation Science Center manages the radiation safety controls in the accelerator.


Radiation measurement in space is one of essential research elements for human beings to set out on a trip to the space. There exists a wide variety of cosmic rays in space. The radiation field around accelerators consists of a wide variety of radiations with high energies, and resembles the filed in space. We are developing the methods how to measure doses by cosmic rays in space.


Passive detector elements using a solid-state track detector have been developed by Radiation Science Center in collaboration with the Japan Aerospace Exploration Agency (JAXA), and are actually utilized as the dosimeter of Japanese astronauts in the International Space Station (ISS) since 2007.

In the case of a passive detector, however, it is necessary to read dose by analyzing the detector elements after astronauts coming back to the earth, and we cannot measure doses in real time during their flight. The space organizations in Japan, United States and Russia prepare a real-time detectors in their space shuttle or ISS, but they are inadequate at the present state for sufficient measurements of doses for long-time stayers in space because there are problems in the detectors such as limitation of measurable species of radiation or not attaining enough accuracy of measurement.

To solve this problem, Radiation Science Center has been developing a new space dosimeter called as PS-TEPC (Position-sensitive Tissue Equivalent Proportional Chamber) in collaboration with JAXA, which can measure various types of radiations with high accuracy. PS-TEPC is a real-time dosimeter constructed using tissue equivalent gas and materials, and has a characteristic to measure the tracks of incident radiation perfectly. Therefore, we can know accurately the track length of radiation passing through the detector and the absorbed dose on biological tissue simultaneously, and we can evaluate dose equivalent from these.

At present, we carry on the development of PS-TEPC aiming the installation of it in ISS in 2015.