May 23, 2013
Lori Ann White
Upgrades to the Facility for Advanced Accelerator Experimental Tests—including a new 10-terawatt laser—will assist in R&D for new methods of particle acceleration.
“Just over a year after opening its beam to researchers from around the world, the Facility for Advanced Accelerator Experimental Tests (FACET) at SLAC is shining a little brighter. With the addition of a new 10-terawatt laser and other equipment upgrades, one of the facility’s main goals—the development of a new method of particle acceleration that boosts particles’ energy on waves of plasma—looks especially promising.
During the facility’s first run, which took place from April through early July of 2012, researchers sent electrons accelerated in the SLAC linear accelerator into a chamber of hot gas, turning it into a plasma. Some of those very same electrons then rode the resulting plasma wave to even higher energies. This accelerated the electrons with great efficiency—thousands of times more in the same distance than the technology used in today’s particle accelerators.
But, as happens so often in basic research, FACET’s first run also revealed the need to make some modifications. Using the accelerated electron bunch to create its own plasma had issues—issues that make the laser a vital addition to the 2013 run, says SLAC Advanced Accelerator Research Department leader Mark Hogan, who is both an important part of FACET and, as one of the leaders of the plasma wakefield acceleration team, a hands-on experimenter himself.
‘Controlling the characteristics of both the electron bunches and the resulting plasma to where the process is efficient enough has turned out to be tough,’ Hogan says. ‘As it is, not enough of the electrons are being accelerated.’
The team will now use the new laser to zap the chamber of hot gas, turning it into a plasma before any electrons enter. That laser-created plasma will be more consistent than the electron-created version, which means that when the electron bunches do enter they’ll cause a more controlled plasma wave.
Selina Li, the SLAC accelerator physicist in charge of the project, says the laser is in good shape and should be operational this summer.”
See the full article here.