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About the ILC

About the ILC…

The International Linear Collider (ILC)

The International Linear Collider (ILC) is a proposed particle accelerator that would be built in a 31km long underground tunnel. It would collide electrons and positrons head on in the middle of the tunnel, and analysis of the collisions is expected to result in new knowledge regarding the creation of the universe, time and space, and mass itself, by ‘recreating’ the Big Bang.

Why are the Kitakami Highlands suitable for the ILC?

The area features a 50km stretch of stable granite bedrock free of active fault lines. Since electrons and positrons are tiny invisible particles, a stable bedrock free of vibration is required when forcing them to collide accurately. Securing a stable 30-50km length is also important. While not all areas are suitable for establishing the ILC, the Kitakami Highlands are one of the few places in the world with all the ideal conditions for establishing the ILC. The granite bedrock under the site covering Oshu and Ichinoseki cities stretches north to south in a gourd shape with its southern side called Senmaya granite and the northern side called Hitokabe granite. The narrowest part of the bedrock separates the two sides. According to the research conducted by Iwate in January 2012, the two granite bedrocks were completely connected. Also, both this research and another concrete geographical survey conducted with Tohoku University from December 2012 to the spring of 2013 concluded that the Kitakami Highlands were suitable for constructing the ILC. While the Tohoku region was seriously devastated by the Great East Japan Earthquake, its underground conditions were found to be very stable. A national observatory, the Esashi Earth Tides Station lies under the Kitakami Highland and their facility was not affected by the disaster at all.

Ideal location
  1. Great access by road, rail, air and sea to the ILC colliding point and other research campus candidate sites.
  2. Potential for distributed living in neighboring cities.
  3. Minimizes public funding by utilizing existing infrastructure and private funding.
  4. Ideal cooperation with Tokyo and Tsukuba (KEK) by Shinkansen as well as highways and other road access.
  5. Worldwide accessibility through the network of Sendai and Hanamaki airports and Narita and Haneda International Airports.
  6. Benefits of urban functions of Sendai and partnership with Tohoku University and many other universities and research institutions.
  7. Sufficient medical and educational potential.
  8. Provides an ideal living environment including a cool climate, Sanriku Reconstruction National Park, ski resorts, hot springs and marine sports sites.
  9. Boasts UNESCO World Heritage Sites, Hiraizumi and Shirakami-Sanchi, unique history and culture, and a rich natural environment.
  10. Safe and secure living environment and a pristine environment free of pollution.


International Linear Collider

The International Linear Collider is a next-generation colliding-beam accelerator, often abbreviated as the ILC. The next-generation model touts a linear accelerator which overcomes the limitation of a circular accelerator, which loses more energy when bending the electron orbit into a circular shape and thus cannot achieve a target energy level. This necessitated a large linear accelerator like the ILC.


CERN or the European Organization for Nuclear Research is located just outside of Geneva, Switzerland near the French border. It is the largest research institute for particle physics in the world and the Large Hadron Collider (LHC) is part of it. The acronym CERN comes from the name of a preliminary organization called Conseil Européen pour la Recherche Nucléaire.


The opposite (antiparticle) of an electron. A positron has a positive charge, in opposition to the electron’s negative charge.

Big Bang

The giant explosion that occurred at the beginning of the universe. According to the Big Bang theory, the universe started approximately 13.7 billion years ago with an explosion (the Big Bang), and as the universe expanded, elementary particles, atoms, molecules, stars, and galaxies were created.

Colliding-beam accelerator

A colliding-beam accelerator accelerates particles by adding energy to them using electromagnetic waves. It forces accelerated particles to collide with each other and observes various particles emerging from clusters of energy created by the colliding particles. The faster the accelerated particles, the greater the energy that is created to generate rarer particles.

The ILC accelerates electrons and positrons up to their ultimate speed of light to achieve the level of ultrahigh energy close to the beginning of the universe.

Superconducting acceleration

When a substance is cooled down to an extremely low temperature, its electrical resistance drops to zero. This is called superconducting acceleration. The ILC introduces this system utilizing this superconducting acceleration to accelerate

Electric fields are created by sending microwaves into a cavity made of niobium, a superconducting rare alloy, to accelerate electron and positron beams. When it’s cooled down to -264 degrees Celsius (the ILC can operate at down to -271 degrees), a superconducting state is created and thus the electric resistance falls to zero. Since there is no electric power loss or heating, particles are given greater energy for smaller electric power and shorter distances.

Elementary particles and Higgs boson

Modern science assumes that elementary particles are the most fundamental unit that composes the world. It is the smallest unit that matter is composed of. There are 17 types of elementary particles confirmed in the standard model of physics including matter-compositing particles, force-carrying particles, and the Higgs boson that gives elementary particles mass.

The existence of mass is a mystery to us. Our mass is due to the kinetic energy of quarks (elementary particles composing matter) moving close to the speed of light. However, the electrons that support our daily lives are found to have mass as well. Electrons are elementary particles, in other words, they have nothing inside, or no kinetic energy in them.

Then why do electrons have mass? The Higgs boson explains this. According to the theory, the Higgs boson in the vacuum prevents electrons from moving. If the Higgs boson really exists in the vacuum, adding great energy would send the Higgs boson particles out.

This is what the ILC is trying to experiment on.

The Higgs boson has a completely different nature from other particles. One aspect of this is that they have zero “spin.” Why is that? Isn’t there anything related to them? We need a super-advanced accelerator, the ILC to solve this mystery.

Theory beyond the standard model

The standard model of physics is the framework that is widely accepted in the field of particle physics. The sole last element that is said to exist but was never identified was the Higgs boson. On July 4, 2012, The European Organization for Nuclear Research (CERN) received news that new particles that seemed to be the Higgs boson were identified.

Was the last element found? Do we now know everything about elementary particles?

Unfortunately that is not the case. While the standard model explains the current universe very well, the theory contradicts itself in a number of ways. We need a new theory that exceeds the existing standard model to fully understand the physics of the universe.

There are powerful theories that could replace the standard model including the super-symmetry hypothesis, the composite particle hypothesis and the extra dimensions hypothesis. Which one is right? The ILC is expected to find the answer as the most suitable experimental tool.

Generation and control of a nano-beam

ILC beams are in an extremely thin ribbon shape and have 10 billion electrons and positrons in them. The size of the beam is 5 nanometers wide at the point of collision. It is as small as 100 hydrogen atoms. They are made small in order to increase the density of electrons and positrons in the beam and increase the frequency of collisions. Electrons and positrons are so small that they don’t seem to have any size and the inside of the beam is hollow even with 10 billion of them.

The ILC adopts technologies to create these ultra-small beams and super technologies to control the colliding point of the beams at a nanometer level of accuracy.


The LHC or the Large Hadron Collider. A Hadron is a large circular accelerator 27km in diameter. Hadrons are particles with inner structure. The LHC forces protons composed of three quarks to collide with each other.