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."

Question

[MyLongNickName]

"Straightest building". Does this mean that the building is constructed to take into account the curvature of the earth? Granted this would only be less than half a meter (if I did the math right), but would seem to be important in this sensitive of a project.

Proton beam

[mattr]

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.

Perhaps antimatter is better than proton beam, I don't know. Sounded like it is extremely expensive to run.. anybody know? I saw how RIKEN uses CAD to design thick IIRC bronze beam masks. It is underground and the whole building is built like a ship apparently, separate from the surrounding earth, which presumably helps it stably ride out earthquakes. They opened in Dec. 2006 the most powerful radioisotope accelerator, accelerating aluminum to 70% c.

I am not a physicist nor do I work there but am curious about these aspects concerning the place mentioned in the article.

Re:I'm more interested in ...

[Thomas Hawk]

I can't remember Bebo's real name but he has been going by Bebo all his life. If memory serves correct, he got the name when he was a child. I think it was what his sister called him and it's the name that stuck with him his entire life. He really is a great guy and gave us a great view of SLAC. I'm looking forward to going back there to take photos and film part III with Robert and Shel.

Straight means completely straight

[Bananenrepublik]

That is the point about straightest building. They're accelerating electrons, so bremsstrahlung (= energy loss due to curves, grows very fast with decreasing particle mass, decreases slowly with the radius of curvature) is a real problem. In order to eliminate bremsstrahlung, the SLAC building doesn't follow the earth's curvature, but instead is straight in the same sense that a lightbeam is straigh.

I once calculated the amount of energy the LEP (CERN's old huge accelerator, a 20km approx. circle) lost due to bremsstrahlung. IIRC it amounted to one 100W lightbulb every 10cm or 20MW of enrergy loss, simply due to the curvature.

Currently a new huge linear accelerator is being discussed inside the scientific community. They want to use supraconducting magnets, which in terms requires large reservoirs of cooling liquids. Since liquids are subject to gravitation it may be that they will build it following the earth's curvature in order to keep the cooling circuits simpler. These issues haven't been decided yet.

Re:Question

[ortholattice]

Not sure if I understand that correctly, but if physicists say that an orbit is a straight line through space/time (in a sense), then it follows that a straight line inside a planetary gravitational field would have a curve to it.

The curve you are talking about is the path that a light beam would follow, not the curvature of the earth. Otherwise, the earth would look flat to someone on the surface, and of course it doesn't, since ships, etc. disappear over the horizon.

That said, I don't understand why the building would follow the curvature of the earth, if what the other poster above who visited there is correct. Could it just be for practical building construction reasons, so that you can wash the floors without the water running downhill to the center? The high-speed particles in the accelerator are going to be affected negligibly by gravity and certainly will not follow the curvature of the earth. Perhaps the accelerator itself is offset at each end compared to the middle?

NeXT and Amiga at SLAC

[derinax]

This takes me back to when I was a NeXT Campus Consultant at Stanford-- one of my duties was the maintenance and sales of NeXT hardware at SLAC. At the time, I was also an Amiga enthusiast, and was amazed to see how entrenched the Amiga was at SLAC. Mostly due to the encouragement of Willy Langeveld, some great scientific apps came out of SLAC for the Amiga: VLT, Hippograph (both Willy's), TeX (authored by Stanford alum Tom Rokicki); I'm sure there were others. I even saw an A500 out on the floor, in production.

The biggest impression I had of SLAC in the late 80's was of gigantic, warehouse-sized rooms filled with massive, unused rusted machinery. Reminiscent of the Orrery in Oblivion, or Oghma's lair from Dark Crystal. Weird and amazing place; but perhaps my memory has augmented the tour a bit.

Re:Longest building in the world?

[Loudog]

I worked at SLAC for more than 6 years, night shift in the accelerator maintenance. It's not the rat droppings, it's the black widows you need to watch for. I once killed more than 20 of them -- and that was in one sector (100m), on one task (ranging). And that's only the ones that were in my way.

I still miss the place, but like my current job better.

-- Loudog
-- Listening to the song of the klystrons