INDUSTRY

On Tuesday morning, September 24, Fermilab’s Tevatron set a record. At 6:14 a.m., the world’s most powerful particle accelerator achieved an unprecedented luminosity, a measure of the number of high-energy particle collisions per second, recorded in inverse centimeters squared per second or cm-2sec-1. The breakthrough luminosity came at a time when the particle physics world is closely watching the current Collider Run II at the Department of Energy’s Fermilab. The Tevatron offers the best opportunity in the world for particle physics discoveries at the energy frontier. But collision rates at the proton-antiproton accelerator have been slow to reach anticipated levels since the run’s start in March 2001 (http://www.fnal.gov/pub/now/tevlum.html). Last week’s 3.02 x 1031 cm-2sec-1 achievement brought the accelerator significantly closer to its near-term luminosity goal of 4.0 x 1031 cm-2sec-1. Reaching this goal requires not only Fermilab’s best efforts, but also physicists from outside the laboratory to lend a hand. Indeed, if there is a silver lining in the struggle to reach the Tevatron’s luminosity potential, it is the opportunity for collaboration and pooled expertise of the world’s experts in accelerator physics and technology. Scientist Yunhai Cai, from the Department of Energy’s Stanford Linear Accelerator Center (SLAC), is developing simulations of beam effects in the Tevatron to help elucidate the lifetime of the accelerator’s particle beams. Physicist Marc Ross, also from SLAC, is providing electronics to facilitate beam transfers between links in the accelerator chain. Ross describes the collaboration between Fermilab and SLAC as a “perfect marriage” because both groups speak the same language of accelerator science. “It is to my benefit to get to know people at Fermilab and to understand the problems of the Tevatron,” Ross said. “The technology and science of what people do is unique here, and I am fascinated by that. The collecting of antiprotons and treating them gingerly because they are so delicate is fascinating. I hope that we can have a positive impact on the Tevatron, and we realize that a lot of people have been working hard on Run II.” The Department of Energy’s Argonne National Laboratory is working with the Tevatron Department to develop a plan to improve the vacuum in the Tevatron by a factor of two. Scientists at Argonne National Laboratory are also studying the need for beam diagnostics to improve proton beam stability as well as beam stability in one of the Tevatron’s feeder accelerators. An accelerator expert, Wolfram Fischer, from the Department of Energy’s Brookhaven Laboratory, recently spent a month at Fermilab to help analyze Tevatron performance. CERN sent Frank Schmidt to Fermilab for six weeks to work with the Tevatron and to take shifts in the control room. Despite the setbacks of Run II, Schmidt maintains a positive attitude. “This is a very hard-working team here, and [the collider run] is moving along well,” Schmidt said. “I still think that the intermediate goals of Run II can be reached.” On his last day in the main control room, Schmidt reflected on his visit at Fermilab. “I would like to come back to Fermilab,” Schmidt commented. “It is fun and important for Large Hadron Collider people to learn from the Tevatron. The success of the Tevatron is an issue for the world community in accelerator physics.” He added jovially, “Let’s see who finds the Higgs first!” Additional visitors from CERN are expected at Fermilab in the upcoming months. And just as CERN has sent physicists to contribute to Run II, Fermilab plans to return the favor by sending Fermilab scientists to CERN to contribute to the commissioning of the Laboratory’s Large Hadron Collider when it comes online later in the decade. Meanwhile, discussions continue with the Department of Energy’s Berkeley Lab about how their world-class accelerator expertise might lend Tevatron support. Each hard-won increase in the Tevatron’s luminosity represents more data for Fermilab experiments CDF and DZero – and a greater chance for discoveries in Run II that will change the understanding of particle physics. The world’s high-energy laboratories are not only watching but also pitching in to help. “It has been extremely gratifying to be fielding offers of support from other labs. It really shows us that there is a widespread feeling that this endeavor is important to everybody, not just Fermilab,” said Steve Holmes, Fermilab’s Associate Director for Accelerators and Interim Head of the Beams Division. “We have a lot of experience here, but there are also strong capabilities outside. And new eyes on the collider often provide insights to help us overcome our problems. The most important thing is that people really want to rally around and help the Tevatron.”