The APS April meeting is over but I still have a few more stories to post and I'll get them up over the next week.
The leading edge of particle acceleration technology in use today is made of superconducting cavities that shape radiofrequency waves for particles to surf to higher energies. However, that technology is limited because the cavities themselves, made of superconducting niobium, have a maximum strength of rf waves that they can sustain.
Machines are now enormous as they strive for the energy frontier that physicists want to explore. There is, however, a limit to the size of big machines, particularly for financial and space reasons. That size limit is the motivation for exploring the alternative techniques being tested now. One of these is plasma wakefield acceleration. It's a promising approach and each year there are great new advances, some of which were reported here today. A topic we haven't really talked about in symmetry is an alternative wakefield approach using lasers.
Wim Leemans of Lawrence Berkeley National Laboratory talked about a project called BELLA that could potentially match the energy of the proposed 20 kilometer International Linear Collider in a few hundred meters instead. The technology is years away from working so that comparison is really just to give an idea of how much greater the acceleration is than conventional superconducting technology. However, if laser wakefield (or plasma wakefield) acceleration is successful, it would open the way to creating compact particle accelerators for medical applications and other uses.
The idea is to create a narrow channel in sapphire with a low density gas inside. A laser is piped down the channel and pushes a bunch of electrons, getting them to high energies. So far, the technique has been demonstrated to work to do some acceleration but hasn't achieved the really high energies needed to be competitive with energy frontier machines like the Tevatron (for now) and the LHC (later this year).
It's exciting stuff and also necessary if particle accelerators are to increase the energy frontier much beyond the LHC and ILC targets.
See all posts from the American Physical Society April 2008 conference here.
