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Dorfan Today: PAC '07

Accelerator science is a vibrant, burgeoning field, as demonstrated by this past week's Particle Accelerator Conference (PAC '07), held in Albuquerque, New Mexico. The conference attracted more than 1,000 participants from the U.S., Europe, Asia and beyond. This year's meeting was so rich with new information that four parallel sessions were needed to fit it all in.

SLAC was very well represented at PAC '07 by more than 20 talks and 100 posters presented by our personnel. Over 50 additional talks and posters were based on research and papers with contributions from SLAC scientific and technical staff.

Over the past few decades, accelerators have become crucial research tools in a broad range of sub-disciplines in both the physical and life sciences. The DOE Office of Science's priorities mirror this broad spectrum of accelerator-based science. The Office of Science operates major facilities for photon science, particle and nuclear physics which serve a user base in excess of 20,000 scientists. This diversity of accelerator-based facilities was reflected in the PAC meeting with the SLAC-based efforts centered on photon sources like SPEAR3 and the Linac Coherent Light Source (LCLS), particle physics machines like PEP-II, the Large Hadron Collider and the International Linear Collider (ILC), and concepts for the far future like plasma wakefield acceleration and laser acceleration.

PEP-II's pioneering role in high-current and high-luminosity e+ e- colliders was the subject of a number of well-received invited presentations as well as poster presentations at PAC '07. With its record beam currents and luminosity, PEP-II is a test bed for other high-intensity machines and the community has been widely interested in our experience in running and improving the machine.

New accelerator technology for extending the reach of future high energy machines was also presented in several sessions. Among those recognized at the conference for outstanding contributions to accelerator science was SLAC's Mark Hogan, who was elected APS-DPB Fellow for his work on electron and positron beam-plasma interactions including the first experimental demonstration of meter-scale wakefield acceleration.

A notable and welcome difference from previous meetings was the growing number of reports on synchrotron-light machines. There were numerous status reports of existing third generation sources such as our own SPEAR3, together with reports of new storage ring sources such as the recently commissioned Australian Synchrotron. There was also a large group of presentations on new technologies, focusing both on single pass, free electron laser sources such as the LCLS that raise the peak brightness and provide extremely short pulses and on emerging proposals for energy-recovery schemes that enhance the average brightness.

The recent successful commissioning efforts of the LCLS were well represented in several talks and posters. The topics covered included the gun technology used in the RF photo-injector and diagnostics for measuring the unique properties of beams produced in machines such as the LCLS.

The ILC was also strongly represented, with more than 45 presentations. The leadership of SLAC in the ILC was underlined by many invited presentations, reflecting the breadth of our contributions which range from the overall design of the facility to the beam delivery system, to supplying the drive power for the linacs, to reliability studies. One of the "hot" ILC topics was the electron-cloud effect, which has the potential to increase the extremely small beam size that must be preserved by the ILC positron damping ring; the experimental work done at the PEP-II Low Energy Ring to understand and mitigate this effect is an important element of the global ILC design strategy to combat the this effect.

There were also numerous presentations on techniques for producing ultra-short bunches for investigating ultra-fast phenomena. This underscores the prominence of the new field of ultra-fast science pursued at SLAC's Photon Ultrafast Laser Science and Engineering (PULSE) center, for example. It is here we see a clear relationship between laser technologies and accelerator science.

I congratulate everyone at SLAC—and beyond—for a very successful conference. Integral to this type of research is the continual rethinking and improving of accelerator technology. This process is greatly enhanced by the exchange of ideas at meetings like the PAC and its counterparts around the globe. The SLAC program, with its concurrent emphasis—both theoretical and experimental—on improvements to the operating machines, development and construction of the next generation of machines, and nurturing of ideas that will take us beyond our current technologies, is playing a major part in ensuring the future health of accelerator-based science.

—Jonathan Dorfan, SLAC Today, July 2, 2007