Decision on the International Linear Collider: “Not what we had hoped for but progress nevertheless”



Lyn Evans

On 7 March 2019, the Japanese government has expressed its position for the International Linear Collider, a proposed particle physics project that would be hosted in the Kitakami mountains in the north of the country. The government has decided to not make a proposal to host the project, but has expressed interest in the ILC project and signalled to continue discussion it with other governments.


The International Committee for Future Accelerators has responded in press briefing, saying that, though disappointed, it welcomes the support the ILC gets from Japan. “We regret that there is no clearer positive statement today but we are still hopeful and see things are moving. It is not the end of the story,” ICFA chair Professor Geoffrey Taylor said. 

ICFA is an international group created to facilitate international collaboration in the planning, construction and use of accelerators for high-energy physics. The Committee has 16 members from the regions most deeply involved in high-energy physics.


Lyn Evans, Director of the Linear Collider Collaboration that coordinates planning and research for the International Linear Collider and the Compact Linear Collider CLIC, said: “Today we did not get the green light we hoped for, but nevertheless there was a significant step forward with a strong political statement and, for the first time, a declaration of interest in further discussions by a senior member of the executive. We will continue to push hard.” 


The Linear Collider Collaboration is an international endeavour that brings together the worldwide community of scientists and engineers that work towards implementation of a future linear collider. Two concepts are studied using different acceleration technologies. The ILC is being considered for implementation in Japan, and CLIC for a possible implementation at CERN. In both cases two linear accelerators will face each other, accelerating and collide electrons and their anti-particles, positrons.


At the ILC, superconducting radiofrequency accelerator cavities operating at temperatures near absolute zero give the particles more and more energy until they collide in the detectors at the centre of the machine. At the height of operation, bunches of electrons and positrons will collide roughly 7,000 times per second at a total collision energy of 250 GeV, creating a surge of new particles that are tracked and registered in the ILCʼs detectors. Scientists would use this wealth of data to measure the properties of particles very precisely, such as the Higgs boson, discovered at the Large Hadron Collider at CERN. It could also shed light on new areas of physics such as dark matter.

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