A team of campus researchers has been awarded a $2.4 million research grant to improve the model of a laser plasma accelerator — technology that could potentially record the making and breaking of chemical bonds at an atomic level.
At the behest of the Gordon and Betty Moore Foundation, the Lawrence Berkeley National Laboratory research team is working on this project as part of an endeavor to develop affordable and compact X-ray free-electron lasers, or xFELS, according to an email from the Moore Foundation’s science program officer Ernie Glover.
According to Wim Leemans, lead researcher and director of Berkeley Lab’s Accelerator Technology and Applied Physics Division and Laser Accelerator Center, laser-plasma technology could be used for universities and hospitals.
“We might be able to produce X-rays that are much more peaked in … energy that the medical folks are interested in,” Leemans said.
According to Glover, xFELS are very large and costly to create and manage, but the Berkeley Lab team is using ground-breaking concepts — funded by money from the grant — to try to change that.
The grant, which was awarded in August, will last three years and be given in two installments, according to Leemans. A majority of the funds will be used to build a state-of-the-art laser system that can produce “electron beams with very high stability” and “all of the characteristics that an electron beam needs to be useful for a free-electron laser.”
In the technology that Leemans and his team are studying, an infrared laser beam is shot through an accelerator structure filled with plasma, a type of ionized gas. This produces an electron beam that is directed at a series of magnets, called undulators, that “wiggle the electron beam left and right,” Leemans said.
In the right conditions, this will produce a type of X-ray that could be used for medical applications, such as radiation therapy.
Leemans likened the movement of the laser pulse to a motor boat moving through a “lake” of electron-filled plasma.
Conventional accelerators use lasers and metal walls that are very costly, according to campus physics professor Jonathan Wurtele.
“Conventional accelerator technology is limited in the strength of energy kicks,” Wurtele said in an email. “It can’t impart more than a certain amount of energy over a given distance.”
To get the desired amount of energy, therefore, conventional accelerators have to be very large.
To get the same amount of energy as from a kilometer in a conventional accelerator, however, it could take as little as a meter in an xFEL, according to Wurtele.
“There is a much smaller footprint in terms of space that you need because our accelerators can generate much, much higher fields in much shorter distances,” Leemans said.
The team hopes to complete the project in three years, within the limitations of the initial grant, but has already made strides in terms of theoretical research and planning, which will ultimately accelerate the final steps of the process.
“There’s (usually) a big gap between proof of principle and the actual device,” Leemans said. “That’s why I’m really excited about this opportunity, because it will essentially allow us to apply everything we have learned over the past few decades on a completely new, state-of-the-art system.”
