Nanotechnology in a Colossal Particle Accelerator
Kaoru Yokoya
Professor,
High Energy Accelerator Research Organization (KEK)
The experimental research of high energy physics has been supported mainly by the development of accelerators in the last 70 years starting from the invention of cyclotron by E.O.Lawrence in early
1930's. As the required beam energy becomes higher, the larger accelerators are in need. The largest accelerator ever built is an electron-positron ring on the border between Switzerland and France. Its circumference is 17 miles.
A general consensus among the high energy physicists in the world is that the next generation electron-positron collider must be a linear collider rather than a ring collider.
There are a few on-going projects of linear colliders in the world. Japan and US are in close collaboration in this field. We are aiming at a linear collider with the total site length about 20 miles, in which electron and positron beams are accelerated by two linear accelerators, focused to tiny spots, and made to collide. In order to obtain a high experimental efficiency the spot size at the collision point must be less than a few nanometers. Very high technologies are needed to create high quality beams, to keep them focused over several miles, and to collide them stably. The smallest beam ever obtained is the one at Stanford university. It is as small as 50 nanometers. Improvements of several orders of magnitude in various technological fields are still needed for the future linear colliders.