Tour of the Stanford Linear Accelerator Center

Thomas Hawk writes "Last month Robert Scoble and I were able to do a video/photo shoot of the Stanford Linear Accelerator Center (SLAC) with SLAC Emeritus Bebo White. SLAC is both the longest and straightest building in the world and is the home of three Nobel Prizes in physics. There is also a video tour available; part one and part two."

Re:Longest building in the world?

[MyLongNickName]

A wall is not a building [wikipedia.org].

Re:Question

[Emnar]

Yes, the building itself does curve with the surface. I have been in it, and if you kneel down on one end you can see the earth's curve looking toward the other end (when there isn't something in the aisle on either side of the cyclotrons).

Re:Proton beam

[niklask]

I visited RIKEN's accelerator in Wako City, Saitama Prefecture, Japan last year and was told they were one of only three facilities in the world manufacturing proton beams for medical purposes. The other two were in Germany and at Stanford, but I was told that Stanford had closed its facility so now there are only two.

You are confused. SLAC != Stanford. SLAC is operated by Stanford under an agreement with the DoE. The accelerator at SLAC does not provide proton beams. It has been a electron-positron machine ever since operations started. It is currently supplying the BaBar experiment with electrons and positrons and it is also undergoing modifications to accomodate the LCLS, the Linacc Coherent Light Source.

Perhaps antimatter is better than proton beam, I don't know.

Better for what purpose? Remember, it is damn hard to store antiprotons, not to mention antimatter.

Re:So...

[Thomas Hawk]

Bebo did mention this and actually showed us an apparatus that they use to realign the the accelerator. It's this big tube that sits beneath the actual accelerator tube and can be moved with Jacks. There is a target that a beam is shot through to make sure it is straight. Here is a photo of an intersection of the tube. http://beta.zooomr.com/photos/thomashawk/735653 [zooomr.com] They didn't have to realign it during the Loma Prieta earthquake though although they did lose power to the accelerator during that earthquake.

Re:Question

[Anonymous Coward]

Yes. The actual accelerator (like all currently built) is truly straight so the distance between the floor of the klystron gallery (the long building on the surface) and beam pipe beneath varies. As someone else mentioned the variation is negligible (from an engineering perspective).

In contrast, the International Linear Collider, which will be tens of kilometres long, will curve to follow the surface of the earth, since it is long enough that it would create engineering problems to try and go in a straight line - you wouldn't be able to just follow a layer of tunnel-able rock, for example.

Re:Question

[athena_wiles]

I think SLAC actually does NOT follow the curvature of the earth. I remember touring it as a fifth grader and being rather amazed when they told us that you can get on rollerblades at one end & have gravity pull you (albeit very slowly) toward the middle.

Also, as one of the previous posters noted, if you have electrons going at relativistic speeds and you force them to curve to match the curvature of the earth, you're essentially going to be creating a sort of a syncrotron radiation source (SLAC does have one of these, but it's not in the main accelerator), and that energy loss isn't advantageous for the sorts of high-energy physics experiments they try to conduct in this accelerator.