90-50-10: BNL marks special anniversaries

Brookhaven National Laboratory celebrated a trio of important anniversaries on 10–11 June as part of the annual Relativistic Heavy Ion Collider (RHIC) and Alternating Gradient Synchrotron (AGS) users' meeting. Dubbed "90-50-10", the celebration recognized the 90th birthday of Ernest Courant – one of four accelerator pioneers who originated the idea of strong focusing – together with the 50th anniversary of the start-up of the AGS and the 10th anniversary of operations at RHIC.More than 20 leading scientists, including two Nobel laureates honoured for work at Brookhaven, took the stage with stories of the early days, fierce international competition and building equipment with their bare hands.

"When I got here, it looked like an army camp, filled with barracks," said Courant, who first visited Brookhaven in 1947. The following year, he joined the laboratory "for good" as a member of the team that was assembling Brookhaven's first accelerator, the Cosmotron. This proton synchrotron was the first machine to send particles to giga-electron-volt energies. In 1952, as Courant recalled, word of Brookhaven's success travelled quickly after reaching the world record of 1.3 GeV – almost five times higher energy than had ever been achieved previously.

It particularly interested European physicists who wanted to build a similar, but larger, machine at CERN. They formed a study group with the Brookhaven team to figure out how it could be done; building an accelerator 10 times more powerful than the Cosmotron with existing technology would have required 100 times more steel, resulting in a 200,000-tonne machine. It was at one of these meetings that Courant, M Stanley Livingston and Hartland Snyder presented the solution of strong, or alternate-gradient, focusing. (This idea was first conceived in 1949 by Nicolas Christofilos, who later worked briefly at Brookhaven. Unaware of the work of Christofilos, the Brookhaven team independently developed strong focusing three years later.) CERN went on to implement this scheme in the Proton Synchrotron, while Brookhaven applied it in the AGS.

Nobel laureate James Cronin spoke of his experiences at Brookhaven, the first time as a research associate at the Cosmotron. "I want to stress that Brookhaven for me was an extraordinary experience, not only because of what I learnt and did in my own physics, but because of all of the people who surrounded me," he said. "I was so lucky to have this experience of interacting with these high-class, smart people going after problems that could be solved with simple, short experiments. That gets into your culture." Later, as a visiting scientist from Princeton, Cronin, together with Val Fitch and colleagues, discovered CP-violation in K0 decays at the AGS, where they had set up a detector built mostly by hand. The experiment ran for only one week in 1964, but earned Cronin and Fitch the Nobel prize in 1980.

Samuel Ting, who shared the 1976 Nobel Prize in Physics for the discovery of the J/Ψ particle with Burt Richter, talked about his experience with precision experiments on the ground, and most recently, in space. He said that in his career of some 40 years one of his most difficult tasks was acquiring the five tonnes of soap (along with 100 tonnes of lead and five tonnes of uranium) needed for AGS Experiment 598, the study that eventually revealed the J/Ψ particle. Ting is now working on a different challenge: sending the Alpha Magnetic Spectrometer (AMS) into space. Backed by institutions from 16 countries (and about 600 scientists), AMS will measure high-energy charged cosmic rays in the search for antimatter, dark matter and other mysteries of the universe.

Looking to the future of accelerators at Brookhaven, Thomas Roser, collider-accelerator department chair, described how stochastic cooling will increase luminosity at RHIC by almost an order of magnitude. Steve Vigdor, associate laboratory director for nuclear and particle physics, explained that this increased luminosity, coupled with detector upgrades, will permit researchers to quantify the properties of the quark-gluon plasma, search for the "critical point" and study local symmetry violations. Vigdor also described Brookhaven's longer-term plans to add an electron ring to RHIC for the study of electron–ion and electron–polarized proton collisions.

At a celebratory dinner, former AGS and later collider-accelerator department chair, Derek Lowenstein, was presented with an Appreciation Award from the US Department of Energy (DOE). Dennis Kovar, the DOE associate director of science for high-energy physics, commended Lowenstein for his "outstanding leadership and service" as chair for 27 years.

• Based on an article for The Bulletin, by Kendra Snyder. For videos of the more than 20 talks, see www.bnl.gov/905010.


Tunnel boring for European XFEL begins

On 7 July the first tunnel-boring machine for the European XFEL started drilling the tunnels for the X-ray laser that will extend for 3.4 km from Schenefeld in north Germany to the site of the DESY laboratory in Hamburg. It will take the machine about a year to excavate two of the photon tunnels plus the main tunnel for the superconducting linear accelerator. It will be joined in late 2010 by a second, smaller machine that will excavate the other sections of the photon-tunnel system.

Before the machine powered up, on 30 June a "tunnel fest" to honour an old custom took place on the site of the future research campus of the European XFEL in Schenefeld. Like mining, tunnel construction in Germany follows a special tradition that still plays an important role for miners and tunnel builders. The tunnel and boring machine were "christened" by their respective patronesses – the tunnel now bears the first name of Hamburg's state minister for science, Herlind Gundelach, and the machine is called "TULA", short for "Tunnel for Laser". The ceremony also featured the blessing of a statue of St Barbara, the patron saint of tunnel works, who is said to protect workers from the dangers connected with their labour.

Around 560 guests from science and politics gathered for the ceremony, which was accompanied in proper style by a miners' choir. As Massimo Altarelli, managing director of European XFEL GmbH, underlined in his welcome address, the occasion celebrated: "A double milestone on the road to the European XFEL. First of all, it marked the overall start of tunnel construction. In addition, this is the first time such a ceremony has taken place under the banner of European XFEL GmbH, the new international research facility that will build and operate the European XFEL. The facility has established itself almost unnoticed in northern Germany in recent months, and today marked its first real public debut." The European XFEL is due to be switched on in 2014.