High Fluence Irradiation Facility (HIT)

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HIT (short for the High Fluence Irradiation Facility, the University of Tokyo) of the Research Center for Nuclear Science and Technology is also located in the Tokai campus, and has been working for cooperative research in the university since the beginning of the 1985 fiscal year. There are two kinds of accelerators. One is 3.75 MV single-ended Van de Graaff accelerator installed with RF or PIG ion source and having four beam lines (BL1 - BL4), and the other is 1 MV tandem type accelerator (Tandetron) with Cs sputter ion source and one beam line (BL5).

High fluence Irradiation Facility "HIT"
(1) Main characteristics of this facility
  1. Two different ions, light ions (H+ or He+) from Van de Graaff and heavy ions from Tandetron, can be irradiated simultaneously at the merging point of the BL4 and BL5 beam lines (dual-beam irradiation).
  2. Ion beams can be swept to irradiate uniformly over a large area of samples with large currents. The beam sweeping is possible at the BL3, BL4 and BL5 beam lines.
  3. Pulsed ion beam irradiation is possible at the BL1 beam line. The pulse width is ~ 1 nano second and the repetition rate of pulses can be varied between 1~ 500 kHz.
  4. Monochromatic neutron beams can be produced by nuclear reactions, such as p-Li and d-d reactions, at the BL2 beam line guided to a neutron beam hall.
  5. Heavy ion microbeam analysis system provides microbeam with as small as 1 micron in diameter. It also enables us to do single ion hit experiment.
  6. Microparticles (typically 1 micron in diameter) can be accelerated by Van de Graaff. It is the highest accelerating voltage for microparticle acceleration in the world. This is mainly used for simulation of cosmic dust.
(2) Main research subjects
  1. Studies on ion beam simulation of neutron irradiation effects of fusion materials, such as modified stainless steels, new metallic materials, metal matrix composites, tritium breeding materials and so on, are made to understand microstructural evolution induced by displacement damage and transmutant gases using the dual-beam irradiation station.
  2. Studies of ion beam irradiation effects on polymers, organic liquids, high-temperature superconductors and ceramics are made using both DC irradiation, pulsed ion beam and microbeam to understand the mechanisms of physical and chemical reactions in the bulk or at the surface of irradiated materials.
  3. The advanced technique for trace element analysis is being developed. Nuclear reactions by light ions are applied to determine trace element profiles in a target material through the precise measurement of reaction products, such as particle induced charged particle, gamma-ray and neutron emission (PICE, PIGE and PINE).
  4. Studies using energetic microparticles such as development of cosmic dust detector installed in exploring satellites. 

Beam lines for dual ion irradiation

Spacial distribution of sweeped nickel ion beam

Typical beam pulse of 1MeV proton

Crater produced by an accelerated Ag particle on the surface of gold.


Hiromi SHIBATA (Associate Professor) shibata@tokai.t.u-tokyo.ac.jp
Takeo IWAI (Research Associate) iwai@tokai.t.u-tokyo.ac.jp
Kenji TAGUCHI (Technician)
Takao OMATA (Technician from ATOX co.) omata@tokai.t.u-tokyo.ac.jp
Masami OSONO (Secretary) masami@tokai.t.u-tokyo.ac.jp


2-22 Shirakata-Shirane, Tokai-mura, Naka-gun, Ibaraki 319-1188, JAPAN
TEL: +81-287-8475 FAX: +81-29-287-8490 EMAIL: hit@tokai.t.u-tokyo.ac.jp

Research Center for Nuclear Science and Technology, The University of Tokyo

Nuclear Engineering Research laboratory, Faculty of Engineering, The University of Tokyo