Director
Takaaki Kajita

2012.4.1

The history of the Institute for Cosmic Ray Research (ICRR) began with an experimental hut in Mt. Norikura at the altitude of 2770m, called Asahi hut, built in 1950 with the Asahi Bounty for Science. This small hut was developed into the Cosmic Ray Observatory of the University of Tokyo in 1953. It was the first inter-university research facility in Japan. The Cosmic Ray Observatory was reorganized to the Institute for Cosmic Ray Research (ICRR) of the University of Tokyo in 1976. Since then, ICRR has been carried out various researches on cosmic rays as an inter-university research institute.

The headquarters of ICRR is located in Kashiwa-campus of the University of Tokyo, Chiba prefecture, Japan. High energy phenomena in the universe and elementary particles are studied by observing various cosmic ray particles. Examples of the well known achievements of ICRR are the observation of a neutrino burst by supernova SN1987A, and the discovery of neutrino oscillations using neutrinos produced by cosmic ray interactions in the atmosphere. In order to promote these scientific activities efficiently, ICRR has three research divisions; Neutrino and Astroparticle division, High Energy Cosmic Ray division, and Astrophysics and Gravity division. ICRR has 3 observatories in Japan; Kamioka Observatory (Kamioka underground, Gifu prefecture), Norikura Observatory (2770 meters asl, Mt. Norikura, Gifu prefecture), and Akeno Observatory (Yamanashi prefecture). In addition, there are 2 major experimental facilities outside of Japan. They are located in Utah, USA and Yangbajing in Tibet, China.

On April 1, 2010, a new “inter-university research institution system” of the Japanese government started. ICRR will continue collaborate with researchers in the field of cosmic rays and astroparticle physics in Japan and abroad, as we did in the previous system. ICRR carries out many inter-university research programs. Every year, approximately 100 inter-university research programs are carried out in ICRR. It should be noted that most of the scientific outputs from this institute are the results from the collaborative effort by many institutions. In order to produce outstanding results, it is very important to carry out an experiment by an international collaboration composed of top-level researchers all over the world. Hence, most of the experimental collaborations that ICRR is involved are international ones.

In recent years, many exciting results have been obtained in the field of cosmic ray physics by various observations in the world. ICRR intends to continue to be one of the leading institutions that contribute to the world community of cosmic ray and astroparticle physics. In order to make an outstanding plan for the future research projects in ICRR, ICRR has periodically formed a committee on future projects. In particular, since mid. 1990’s the construction of a gravitational wave detector (KAGRA) to discover the gravitational wave and to initiate the gravitational wave astronomy has been the top priority future project for ICRR. In 2010, this project was approved and funded by the Japanese government. We thank all of you who have been supporting this project. Following the approval, ICRR has established “Gravitational Wave Project Office”. The construction of KAGRA will be carried out with the initiative of this office.

Following the start of the KAGRA construction, we think that it is the time to start discussing the future research projects of ICRR. For this purpose, we have formed the Committee on Future Projects. In addition, the scientific activities are reviewed in FY2012 by the External Review Committee. Through these activities ICRR tries to keep update the scientific projects.