Fermilab's Recycler beams take electron cooling to new heights

August 23, 2005

After 10 years of preparation, a team at Fermilab has achieved electron cooling at high energy. On 9 July, on the first attempt, the Electron Cooling Group observed the interaction between an 8 GeV antiproton beam and an electron beam travelling at the same speed. Although commissioning will take another couple of months, accelerator experts have already begun to use the electron-cooling system to reduce the size of antiproton beams prior to their injection into the Tevatron proton-antiproton collider. Ultimately, they hope that electron cooling will increase the collider's luminosity by 50-100%.

Electron cooling, first proposed by Gersh Budker in 1966, is a proven method at low energies, but Fermilab, funded by the Office of Science of the US Department of Energy, is the first laboratory to extend the method to relativistic beam energies (see CERN Courier June 2002 p21). The higher-energy system has been developed at Fermilab under the leadership of Sergei Nagaitsev, who joined the laboratory in 1995. Installation of the system in the Recycler storage ring, which stores and cools antiprotons, began in August 2004.

Constructed in the late 1990s, the Recycler is 3.3 km in circumference and uses permanent magnets to store antiprotons at 8 GeV. The new electron-cooling system mainly reduces the longitudinal emittance of the beam by "mixing" the antiprotons with a continuous 4.3 MeV beam of electrons, which are provided by a Pelletron accelerator adjacent to the ring. The electron beam, with a current of up to 0.5 A and power of up to 2 MW, travels for approximately 20 m along the same path as the antiprotons, and is then sent back to the Pelletron for recirculation. The electrons interact with the antiprotons, cooling the beam and reducing the spread in longitudinal momentum: antiprotons travelling too fast are slowed down as they bump into electrons, and slow antiprotons are sped up as they are hit by faster electrons.

A stochastic-cooling system, based on the principle invented by Simon van der Meer at CERN in 1972, already reduces the transverse emittance of the Recycler's antiproton beam. With the start-up of the electron-cooling system, it is the first time that two beam-cooling systems have been used concurrently, according to Nagaitsev, and that electron cooling has been used to improve beams for a collider.

Source: CERN

Explore further: Record-breaking luminosity boosts discovery potential at Fermilab's Tevatron collider

Related Stories

Antimatter atoms ready for their close-up

February 7, 2011

Two international teams of physicists, including RIKEN researchers (Japan), have trapped and manipulated atoms made out of antimatter, in milestone experiments that should help to reveal why the substance is so rare in our ...

When matter and antimatter collide

December 24, 2010

Antimatter, a substance that often features in science fiction, is routinely created at the CERN particle physics laboratory in Geneva, Switzerland, to provide us with a better understanding of atoms and molecules. Now, Japanese ...

Physicists find ways to increase antihydrogen production

May 20, 2015

(Phys.org)—There are many experiments that physicists would like to perform on antimatter, from studying its properties with spectroscopic measurements to testing how it interacts with gravity. But in order to perform these ...

Recommended for you

Exploring the physics of a chocolate fountain

November 24, 2015

A mathematics student has worked out the secrets of how chocolate behaves in a chocolate fountain, answering the age-old question of why the falling 'curtain' of chocolate surprisingly pulls inwards rather than going straight ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.