'Mini' ion accelerator showcased

Cowan, director of the Nevada Terawatt Facility at the University, and his research partners have produced a proton beam that has 100 times higher quality than any conventional particle accelerator and fits on a tabletop.

Irradiation with accelerated carbon ions can pinpoint a tumor and destroy it without sacrificing surrounding tissue, making possible treatment for some cancers, such as those in the head region, that were previously untreatable.

Reducing the size, and thus ultimately the cost, and improving the quality of the ion beam could provide broader access to basic research as well as applications such as ion beam cancer therapy, Cowan said.

"This could result in cheaper and more readily available ion beam cancer therapies, which have been shown to be far more precise in treating cancer than conventional therapies," he added.

Using ultra high-intensity, short-pulsed lasers to irradiate thin metallic foils, Cowan and his team have generated a high-current beam of protons and ions.

"In principle, this could replace roughly 30 feet of conventional radio frequency accelerators," Cowan told attendees at the American Physical Society meeting here. The experiments were performed at the Laboratoire pour l'Utilization des Lasers Intense (LULI) laser facility at the Ecole Polytechnique near Paris, France, and at the Los Alamos National Laboratory, N.M., using its Trident laser.

Current particle accelerators, by comparison, include the Department of Energy's Fermilab accelerator in Illinois, which is four miles in circumference, while the huge CERN European Laboratory in Switzerland -- made widely popular in the Dan Brown novel, Angels & Demons -- is nearly 17 miles in circumference.

Cowan leads a team of approximately 65 at the Nevada Terawatt Facility, which houses a 2 trillion watt Z-pinch. The Terawatt team is bringing the Z-pinch together with a one-tenth-scale petawatt laser to create the only facility in the world with this capacity. The facility also boasts strong in-house theory and simulation capabilities supported by a 48-node cluster computer.

Research areas underway at the Terawatt Facility include wire array physics, laboratory studies of astrophysics, dynamic processes in material science, ultra-strongly magnetized solids and plasmas, advanced backlighters, laser plasma and laser solid interactions, laser plasma acceleration, and ultrafast x-ray sources.

The Terawatt Facility theory team is also developing simulations to support experiments that include Department of Energy-funded Lawrence Livermore, Los Alamos, and Sandia National laboratories; LULI; the Institute for Laser Engineering at Osaka University in Japan; and the Max Born Institute and the Gesellschaft fuer Schwerionenforschung in Germany.

Research funding at the facility nearly tripled since 2001 to $8.5 million. Papers published in top refereed publications such as Nature, Physical Review Letters, Physical Review and Physics of Plasmas, as well as refereed conference proceedings, has grown nearly six-fold in four years to 46 papers in 2004.

Cowan joined the Nevada's physics department in April 2003. He completed his undergraduate work at the California Institute of Technology, Pasadena, and his graduate studies at Yale University. He spent 13 years at the Lawrence Livermore National Laboratory, and two years at General Atomics in San Diego before joining the University.

Source: University of Nevada, Reno