Linear collider gains key insights from Cornell physicists

Jul 04, 2013 by Byanne Ju
Linear collider gains key insights from Cornell physicists
A schematic of the proposed International Linear Collider, which includes the damping rings designed by Cornell physicists. Credit:

The International Linear Collider (ILC), a global effort to build a particle accelerator that may unlock some of the universe's deepest mysteries, has received pivotal insights from Cornell physicists: They have designed a key component of the proposed collider, called a damping ring, without which the ILC's powerful particle collisions wouldn't be possible.

Last month, the ILC's globally coordinated Technical Design Report – the master document that outlines how to build the ILC – was officially completed and handed over to the International Committee for Future Accelerators (ICFA), the organization that commissioned the study.

The document reflects the culmination of an ongoing project started at Cornell in 2008 that has reconfigured CESR (Cornell Electron Storage Ring), the electron-positron colliding beam machine at Wilson Synchrotron Laboratory, as an ILC test bed.

The National Science Foundation-funded project is called Cornell Electron Storage Ring Test Accelerator (CesrTA). Principal investigator David Rubin, professor of physics, has led the effort to leverage the uniquely flexible design of Cornell's synchrotron to turn it into a prototype ILC damping ring.

The ILC's purpose is to make billions of electrons and their , called positrons, collide with each other in a fiery ball at the speed of light. The collisions would recreate conditions during the big bang and possibly answer questions of how the universe began.

The ILC would be a complementary machine to the Large Hadron Collider in Switzerland, a proton-proton collider that recently made international headlines by identifying the mass of the "God particle" – the Higgs boson. Plans for the ILC include a "Higgs factory" to study the properties of that recently discovered particle.

Before the electrons and positrons collide in the accelerator, they have to first be cooled, focused and tightly packed in a beam. That happens in a damping ring, a circular accelerator that accepts hot bunches of positrons or electrons, and prepares the beams for acceleration and eventual collision at the end of a 9-mile straightaway.

"What we needed to do is make the beam cool, make it compact so all the positrons are going in the same direction, and focus them down to a very tiny spot, where they will then collide with similarly focused electrons," Rubin said.

The CesrTA project, in collaboration with an international Damping Ring Working Group, designed the ILC damping ring with magnets called wigglers that wiggle the beam back and forth to emit synchrotron radiation, which cools the beam.

However, the positrons and the synchrotron radiation present a formidable challenge: a phenomenon called the electron cloud, which is extra electrons emitted from the beam pipe vacuum chamber. The electrons can ruin the quality of the beam, which is measured in terms of "emittance," by interacting with the positrons and causing instabilities.

The CesrTA researchers developed instruments to measure the electron cloud and ran experiments on different kinds of vacuum chamber coatings and geometries to minimize the electron cloud effect and present the best damping ring design to the IFCA.

CESR was a good fit for the ILC damping ring test bed because Cornell high- energy physicists had previously made superconducting wigglers similar to the damping wigglers needed for the ILC, Rubin said. Also, CESR is one of the few electron storage rings in the world that makes positrons; most synchrotron light sources use only electrons. Finally, CESR is flexibly designed to do science of all types, Rubin said, and Cornell has a long tradition of accommodating multidisciplinary enterprises. The CesrTA program shares the accelerator infrastructure at Wilson Lab with the Cornell High Energy Synchrotron Source X-ray facility.

CesrTA is continuing to collect data on how particles in low-emittance beams interact with their environment and each other.

Explore further: The risks of blowing your own trumpet too soon on research

add to favorites email to friend print save as pdf

Related Stories

New 31-km-long International Linear Collider ready for construction

Jun 12, 2013

Today the Linear Collider Collaboration published its Technical Design Report [PDF] for the International Linear Collider (ILC) - a proposed 31-kilometer electron-positron collider that will both complement and advance beyond the physics of the Large Had ...

Clearing Electron Clouds

Aug 02, 2007

Clouds might be welcome during a drought, but you definitely don't want them in your beam pipes. Researchers around the world are working out how to keep a section of the proposed International Linear Collider—the ...

Groovy Project Solving Cloudy Problem

Sep 07, 2007

Experiments in the PEP-II accelerator have shown that beam pipes with grooves can snare unwelcome electrons, greatly reducing the formation of electron clouds that can disturb the beam.

Recommended for you

Hide and seek: Sterile neutrinos remain elusive

1 hour ago

The Daya Bay Collaboration, an international group of scientists studying the subtle transformations of subatomic particles called neutrinos, is publishing its first results on the search for a so-called ...

Novel approach to magnetic measurements atom-by-atom

6 hours ago

Having the possibility to measure magnetic properties of materials at atomic precision is one of the important goals of today's experimental physics. Such measurement technique would give engineers and physicists an ultimate ...

Scientists demonstrate Stokes drift principle

9 hours ago

In nature, waves – such as those in the ocean – begin as local oscillations in the water that spread out, ripple fashion, from their point of origin. But fans of Star Trek will recall a different sort of wave pattern: ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

1 / 5 (1) Jul 04, 2013
The only useful next generation linear collider is CLIC. It has 6 times higher collision energies (3Tev compared to 0.5Tev). It`s much more build for the future and could create far greater breakthroughs even beyond LHC. And since CERN has BY FAR the worlds largest physics research budget and since CERN has already said they want the next generation collider build at CERN it seems they will determine if it`s CLIC or ILC.

And why would CERN fund billions of Euro`s on a 10-25 Billion dollar (depending on who you listen to) next gen linear collider in Japan. European politicians will not accept it. Unless Japan pays an incredible high percentage of the cost. And with Japans debt reaching 250% of GDP compared to 107% for the US and 89% debt to GDP for the combined EU it seems clear Japan will not be eager to pay so many billions.

And it would be new money as well. CERN with it`s 1 Billion annual budget can fund a very large part of it without asking for extra funding. Money talks.