Shaken But Not Stirred

Although it isn't designed to detect earthquakes, many synchrotron facilities around the world, especially the latest generation facilities, can actually detect when an earthquake is occuring, some time halfway around the world. The recent earthquake in Southern Illinois that occured a couple of weeks ago was certainly felt in various parts of Chicago, and it was certainly detected by the Advanced Photon Source at Argonne.

The magnitude 5.2 earthquake that shook southern Illinois was “detected” by the beam position monitors that keep the electron beam on course in the APS particle accelerator (see the accompanying figure), but the machine continued to orbit electrons at nearly the speed of light with no noticeable adverse effects. Other monitors (x-ray beam position monitors) assured that x-ray beams illuminated experiment samples as small as molecules.

There are of course many steps in place to either make sure the beam continues to be stable, or in the worst scenario, that it gets dumped safely if it goes too far off course. The same thing is in place in many other facilities around the world, especially the LCLS being constructed at SLAC in the earthquake-prone California, which has an even more stringent beam operating parameters to produce its FEL.

I was told by someone working at the APS that they even detected the huge earthquake in the Indian Ocean from a few years ago that caused the massive and deadly tsunami. So this is one very sensitive machine with very precise diagnostics ability.

Zz.

UK Woes Could Impact Euro Physics

The budget crisis in the UK could have an impact in physics activities in the rest of Europe. A case in point is the necessary upgrade of the European Synchrotron Research Facility (ESRF).

Britain is a major partner; but with its physics funds under pressure, it is unclear how much the UK can contribute.

Strangely enough, this is the one area in which the US has followed up on the necessity to invest in light source upgrades. The LCLS has sufficient funds to proceed, and the NSLS II facility is proceeding along as expected. But then again, these are in the Basic Energy Science (BES) division of the Dept. of Energy, which was not devastated by the recent budget cuts, unlike the HEP and Nuclear Physics divisions.

Zz.

Compact Synchrotron Is Unveiled

This is another advancement in the wakefield accelerating technique for particle accelerators. This time, using a laser plasma wakefield and an undulator, they have managed to create the same type of radiation produced at large synchrotron centers (free registration required to view article), all inside a standard-sized laboratory.

Now, Dino Jaroszynski of Strathclyde University in the UK, together with colleagues at Friedrich-Schiller-Universität in Jena, Germany, and Stellenbosch University in South Africa are the first to have combined a laser-driven plasma wakefield accelerator with an undulator to make a compact source of synchrotron radiation.

The team’s wakefield accelerator can accelerate electrons to 1 GeV, which can create X-ray synchrotron radiation with a very narrow bandwidth. What's more, the wavelength of the radiation can be tuned from the far infrared (terahertz frequencies) to hard X-rays by simply changing the energy of the electron beam.

Such technique, such as plasma wakefield, laser-plasma wakefield, and dielectric wakefield, are show more promises of being a feasible technique for new acceleration scheme. The next few years should be very interesting, especially if the delay in the ILC might cause some people to start thinking of other accelerating structures.

Zz.

Relativistic Tennis with Photons

Whoa! If this thing really works, all those multi-million dollar x-ray FEL facility such as the LCLS being constructed at SLAC might be obsolete!

Reported in today's Science daily news (link open only for a limited time), a team from Advanced Photon Research Center at the Japan Atomic Energy Agency has shown the ability to generate an ultrashort and ultraintense x-ray pulse using just ordinary laser.

However, Sergei Bulanov of the Advanced Photon Research Center at the Japan Atomic Energy Agency in Kyoto and colleagues say they have a prototype that can generate pulses of x-ray laser light on the cheap. The researchers call their technique "relativistic tennis with photons," but a more violent analogy may better convey how it works. Suppose you throw a golf ball at a locomotive that is speeding toward you. The golf ball will bounce off it and come flying back at you with tremendous energy--just before you get run over.

The golf ball is a pulse of ordinary low-energy photons. With a tabletop setup, Bulanov and colleagues create the equivalent of a locomotive by firing a different laser into a cloud of plasma, where it creates a wake that travels at near-light speed. When the photons hit the wake, their energy increases 56-fold. They are also focused into an ultrashort, ultraintense blast by the wake, which is shaped like a miniature radar dish.

They have recently uploaded two preprints on ArXiv that you may want to check out:

1. Relativistic Tennis with Photons: Demonstration of Frequency Upshifting by a Relativistic Flying Mirror through Two Colliding Laser Pulses


2. Generation and Observation of Coherent, Long--Lived Structures in a Laser--Plasma Channel

Zz.

To Boldly Do What No Laser Has Done Before

This is an informative article of the LINAC Coherent Light Source (LCLS) that is being built at SLAC. The world-famous high-energy physics facility is being "retrofitted" to become a "light source" and transforming itself from a particle collider to a user facility to generate light to be used to study other things.

Zz.

Lightsource.org

I have made repeated mention of synchrotron centers. If people are curious on what they are (and if you want my opinion, you SHOULD know what they are because there's a good chance your tax money is being used to build one), then you should go to this link:

http://www.lightsources.org/cms/

This site list all the activities related to synchrotron centers, and has a comprehensive listing of ALL the synchrotron centers (and other light source centers) all over the world. Eventually, if it hasn't already, it will include all the FEL (free electron laser) centers since these are also light sources that promises to be of great use in the future.

The National Synchrotron Light Source (NSLS) that I had mentioned in my earlier entry where I made my 1 1/2 second worth of fame, is one such center. If you are in the New York City/Long Island area over the summer, you may want to keep an eye on the Brookhaven Lab (where the NSLS is located) website for their yearly Summer Sunday Tours. One of these tours will focus on the NSLS, which along with the RHIC tour, is one of the most popular places to visit during this event.

So, go familiarize yourself with this thing. See what have been done and can be done at such a center. You could be finding out about something that you didn't know before!

Zz.