Research Could Cut Energy Use of High-Tech EquipmentWednesday 18th November 2015
Certain technologies demand very high energy use, such as high-tech medical technology. As these technologies have life changing effects, hence it can be difficult to alter the energy demand and to make energy savings. But a new discovery by physicists at the University of Maryland could hold the key to the construction of inexpensive, broadly useful, and portable particle accelerators in the very near future.
The team has accelerated electron beams to nearly the speed of light using record-low laser energies. Generally speaking, the approach works by shooting a laser pulse into plasma, which is a gas (in this case, hydrogen) that has been fully ionized to remove all the electrons from the gas atoms. An intense laser pulse can create a plasma wake that follows the laser, much like the water wake that trails a speedboat. A bunch of electrons following the initial laser pulse can “surf” the waves of this wake, accelerating to nearly the speed of light in millionths of a meter.
Previously efforts needed much bigger laser energies to accomplish this effect. So Howard Milchberg a professor of Electrical and Computer Engineering the senior author of the study. and his team tried a different approach, instead they started forcing the plasma itself to transform a weak laser pulse into a very intense one.
The UMD team took advantage of a self-focusing effect, drastically increasing the density of the plasma to as much as 20 times that used in typical experiments. In the process, they dramatically reduced the laser pulse energy needed to initiate the relativistic self-focusing and thereby generate a strong plasma wake.
The UMD laser-driven accelerator produces a beam of electrons and radiation, including gamma rays, which can be used for safe medical imaging and other applications without the need for significant levels of radiation shielding outside the beam path. The secondary effect is that they accelerated the beams to almost the speed of light in less than 1 millionth of a meter.
Immediate applications, such as ultra-fast medical and scientific imaging, the main barriers to laser-driven acceleration are cost, complexity, and portability plus reducing the energy needed for such applications.
To read the technical details go to the article by Matthew Wright on the UMD website.
Wednesday 18th November 2015