Radiation Physics Group

Radiation Physics Group conducts the studies on radiation physics and radiation measurements applicable to the accelerators science.

Purpose and Vision

Radiation Physics Group conducts the researches and developments on the radiation physics and radiation measurement which are fundamental for development and stable operation of accelerators.


Radiation Physics Group researches on interaction processes between substances and radiations generated from accelerator in operation and the methods of radiation measurement. It is important for the radiation safety and control in accelerator facilities to understand the mechanism of interaction between substance and radiation having various species and energies, and to develop the detectors using the knowledge about the interaction process.

So far, we have measured the efficiencies of ionization and scintillation which are important data for understanding the energy loss of radiation and the transfer of radiation energy to substances, and conducted measurements of particle species and the energy releasing after incidence of high energy photons, neutrons and heavy ions to substance. These are utilized as the fundamental data for the developments of detectors and shielding design in the accelerator facility.

On the other hand, it is important to develop the radiation detectors for each purpose in order to measure these fundamental data. Our group develops active detectors combining the ionization chamber, semiconductor detector and scintillation detectors. This radiation detection technology is also utilized to the radiation safety management of accelerator. As a passive detector, we develop the personal dosimeter (PADLES) combining a solid-state track detector and a thermo-luminescence dosimeter. PADLES has sensitivity for photons, electrons, neutrons and charged particles (from proton and iron ion), and can also measure radiations generating from high-energy accelerators. At present, PADLES is practically used for area monitoring in International Space Station (ISS) as well as to measure personal exposure dose of the Japanese astronauts.

For the researches related to the radiation safety management, we are engaged in studies of the dosimetry for radiation emitted with high energy in extremely short period and the calibration method of radiation measurement instruments such as radiation monitors. In addition, we collaborate with other research group and proceed the R&D studies related to environmental radiation and transport phenomena of radiation in substance.