J-PARC Position in the world

J-PARC is a research-facility complex covering a variety of research programs. Proton accelerators form the basis of this complex. Two fundamental parameters specifying the performance of a proton beam are the beam energy and the beam intensity.

Beam power, which is given by the product of these two parameters, is another important parameter for the practical use of proton beams. The figure below shows an energy-intensity graph, in which the performances of proton-beam facilities in the world (in operation, under construction and proposed) are plotted. Since both axes of the graph are in logarithmic scale, points on a straight line (from upper left to lower right) correspond to the same beam power.


Accelerators of J-PARC

At J-PARC, a proton beam is accelerated to a world-class high-energy beam by a series of accelerators, which consists of

・A 400 MeV linear accelerator
・A 3 GeV rapid cycling synchrotron (RCS)
・A 50 GeV (currently 30 GeV) main ring (MR)

The high–energy beam is delivered to three different experimental facilities for conducting cutting-edge research in the fields of materials and life science, and particle and nuclear physics. Please click a red circle on the map to see the inside and the details of each accelerator or experimental facility.


Please click "About Accelerator" for the details


Slide Show


RCS Injection

RCS Extraction


Visit of J-PARC accelerators

At the J-PARC, proton accelerators operate for the purpose of supplying a high-energy proton beam for experiments by global users. We deliver the beam to the facilities for over 24 hours and 200 days. (except for the maintenance period during summer)

You are welcomed to visit our facilities.

1) Open House (principal once a year)
We open facilities that are not usually accessed.
However, open house for 2014 has been cancelled.
(The picture below shows open house in 2012)

OpenHouse1 OpenHouse3

2)Group tour
As a member of group tour, which is available during summer shutdown.
Please contact us after checking the operation plan on this website.
For more details, “a group tour”.