International Linear Collider

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The International Linear Collider is a proposed linear particle accelerator. As of 2005, it is planned to have a collision energy of 500 to 1000 GeV, and to be completed in the late 2010s. Currently the country that will house the accelerator is still not decided (as of October 2006).

It will collide electrons with positrons. It will be between 30 km and 40 km long, more than 10 times as long as the Stanford Linear Accelerator, the longest existing linear particle accelerator. The proposal was previously known by various names in different regions; see below.

[edit] Comparison with LHC

There are two basic shapes of accelerators. Linear accelerators, such as the accelerator in SLAC and the ILC, accelerate the elementary particles along a straight path. Circular accelerators, such as Tevatron, LEP, and LHC, use a circular orbit.

The ILC will have a lower energy than the Large Hadron Collider (LHC), which is also due to be completed earlier, in 2007. However, the effective collision energy at the ILC will be greater than the effective collision energy of the protons in the LHC, even at 14000 GeV. This is because the actual collisions between protons happen between the quarks, antiquarks and gluons which compose the protons, so each individual collision has a lower energy at the LHC. This is still somewhat higher than the ILC collision energy, but measurements can be made more accurately at the ILC since a collision between an electron and a positron is much simpler than a collision between many quarks, antiquarks and gluons. Hence it is anticipated that the ILC will be used to make precision measurements of the properties of particles discovered at the LHC.

Thus the data provided by the LHC and the ILC are complementary.

[edit] Merging of regional proposals into a worldwide project

In August 2004, the International Technology Recommendation Panel (ITRP) recommended a superconducting technology for the accelerator. After this decision the three existing linear collider projects - the Next Linear Collider (NLC), the Global Linear Collider (GLC) and Teraelectronvolt Energy Superconducting Linear Accelerator (TESLA) - joined their efforts into one single project (the ILC). Physicists are now working on the detailed design of the accelerator. Steps ahead include obtaining funding for the accelerator, and choosing a site.

In March of 2005, the International Committee for Future Accelerators (ICFA) announced the appointment of Dr. Barry Barish as the Director of the Global Design Effort. Barry Barish was previously head of the ITRP. At his inaugural speech at the 2005 International Linear Collider Workshop (LCWS05), he outlined his desire for a fully costed Conceptual Design Report for the ILC by the end of 2006.

[edit] External links

• International Linear Collider Website
• "What is TESLA?", a page about the DESY-based TESLA proposal
• Karl Van Bibber about the NLC
• In symmetry magazine:
  • Special issue, August 2005
  • "out of the box: designing the ILC", March 2006