Cosmic-ray Radiation Measurement Laboratory

T. Tamura

Tadahisa Tamura

Office: 6-302 Ext.: 3341


03/1993, D.Sci., The University of Tokyo

Research Field

Radiation detection, Astroparticle Physics

Research Overview

Study on high energy phenomena by observing cosmic rays and gamma-rays.

Research Subjects

1. Development of an instrument, CALET, to observe cosmic rays on the International Space Station
2. Research and development of particle detectors with high energy particle accelerators
3. Study on the interaction of high energy particles with the LHC accelerator in CERN


High energy phenomena like supernova explosions and back holes occur in the universe. In such environments, electrons and protons must be accelerated up to very high energy closing to the light speed. They are called “cosmic rays” and can be observed at the Earth. I have been developing detectors to measure radiations and particles to observe them at altitudes of balloons or the International Space Station.
In balloon experiments, payloads of about 300 kg are brought up to altitudes around 40 km where the atmospheric pressure is reduced to a few hPa. Cosmic rays can be observed in such low pressure environment before they are attenuated by the atmosphere. In order to observe cosmic-ray electrons, our collaboration group carried out several balloon observations in Japan and also performed a long duration balloon observation for 2 weeks in Antarctica.
Successful results obtained from these balloon experiments have led to a project to observe cosmic rays at the International Space Station. I am involved in the JAXA project to develop the CALET instrument. In development from the very beginning, detector structure designs, developments of front end electronics and data taking system, simulations to optimize detector capabilities, tests to evaluate performance of instruments, and so on are needed. Originality to derive scientific results from taken data is also very important for data analyses.
Our measurements of radiations and particles have a lot of techniques which can be applied to measurements of environmental radiations and medical instruments such as PET (Positron Emission Tomography).

  • 1) CALET upper limits on X-ray and gamma-ray counterparts of GW 151226, The Astrophysical Journal Letters, Volume 829, Number 1 (2016) L20 (5pp).
  • 2) Relativistic electron precipitation at International Space Station: Space weather monitoring by Calorimetric Electron Telescope, Geophysical Research Letters, 43 (2016) 4119-4125.
  • 3) A balloon experiment using CALET prototype (bCALET-2), Advances in Space Research, 55 (2) (2015) 753-760.
Affiliated Academic Organizations

T. TAMURA The Physical Society of Japan, The Astronomical Society of Japan

Current members
◯ Professors: 1 ◯ Research Associates: 0
◯ Postgraduates: 0 ◯ Undergraduates: 7

Facilities: Wire bonder
Number of graduates: B. Eng.: 4, M. Eng.: 0, D. Eng.: 0