Have I mentioned yet how beautiful Montreux is?
Anyway, today we went down to Meyrin (a small town outside Geneva) to see the nuclear laboratory there. We’re nerds, we can’t pass up an opportunity to visit our Mecca.
That’s Jason and I next to a portion of a particle accelerator tube.
A lot of nerds across the world apparently wanted to visit, as well, so we had to reserve tickets 15 days in advance and show up on time, at 11 in the morning. Geneva is, because of traffic, about a 1 1/2 hour drive from Montreux. We had enough time to pick up croissants. I had one with chocolate. Croissant and chocolate never really mix, in my mind, but they’re good individually and not too bad together.
We got to CERN almost exactly as the tour started, after some difficulties finding parking. The campus reminded Dad of the Lockheed Martin complex in Burbank, California where he used to work.
The tour guide seemed smart, and knew a decent amount of the physics and engineering that went into the accelerators. We guessed he was a physics Ph.D. who retired and decided to become a tour guide.
On the tour, we got to see the Synchro Cyclotron and the ATLAS control room. The Synchro Cyclotron was the first particle accelerator, and helped get CERN off the ground. It was big, in the sense that it filled a room with solid metal, but not big in the sense that it was smaller than the 27km circle of the LHC, which made the more recent discovery of the Higgs Boson that’s made headlines. The Synchro Cyclotron accelerates protons at only up to 80% the speed of light (600 MeV (Mega Electron-Volts)). Of course, in 1954 that was pretty good, and was still useful to make some discoveries.
For those who don’t know, particle accelerators do just that – they accelerate particles. Generally they do that with a setup of powerful RF fields that pull the particles faster and faster in a ring, confined by powerful magnets, closer and closer to the speed of light. Once they’re going fast enough, they send the particles off into another tube, which ejects the particles at a target.
In the case of the LHC, the target is more protons going the other way.
So, particle accelerators generally have three parts: The ring to hold the protons, the magnets to accelerate the protons, and a detector to see what happens when the particles crash into each other.
The Synchro Cyclotron fit all of this into a single room. Apparently over the decades it was active, the continuous exposure to the high energy particles inside irradiated the metal, so when they shut down the machine they encased it in concrete for a few decades before opening it up to visitors. Even now there are signs posted around it saying things like “Caution radiation, guided tours only.”
I didn’t feel any tingling, so I probably wasn’t affected too much.
After seeing the Synchro Cyclotron, the tour guide took us to see the ATLAS control room. ATLAS is one of the four detectors (sometimes referred to as “experiments”) on the biggest accelerator at CERN: The Large Hadron Collider (LHC), which is 27km in circumference.
It’s the largest such accelerator in the world. The U.S. started work on a larger one several years ago in Texas (near Waxahachie), but that got quite expensive so now we borrow the LHC.
We couldn’t visit the detector itself, because it’s 100m underground and was running at the time. It’s 6 stories tall, and weighs more than the Eiffel Tower.
The control room was awesome, even without the detector itself (though there was a LEGO model of the detector). The control room looked like a space mission control room from the movies (or from real life, really, but most people see them in the movies). It was a large room full of desks each with several computer monitors, all facing the front of the room which had a wall full of projected screens. The status of the detector was displayed there. So was the status of the beams – periodically (roughly once a day) – they inject new protons into the accelerator and accelerate them, and then leave them spinning for a while. While the protons are whipping around the 27km accelerator, 11,000 times per second, the physicists will occasionally pull a few billion protons out of the stream into a detector. So over the course of a day, the beams will both thin out and slow down, because of friction. They had graphs of these quantities on the walls.
When particles are colliding, they are recording 600 million events per second – this gets filtered down to around 100 events per second using powerful (and fast) computers. NI (where I worked last summer) makes hardware that does that sort of filtering.
Quite cool, to say the least.
On the way out of the tour, we stopped by a sculpture they installed after finding the Higgs boson and then went to the gift shop for our souvenirs. They had actual data tapes for sale. And yes, they do store data on tapes still – CERN stores petabytes of data, and hard drives are still too expensive. We ended up getting shirts, although they were out of the men’s t-shirts, so we all got women’s t-shorts. Later, when we got home, we discovered they didn’t fit at all.
After CERN was time to stop for lunch in Geneva and head home. Lunch/dinner (it was around 3) in Geneva was uneventful, save for driving by the largest artificial geyser in a lake I’ve ever seen.
Really just the largest geyser I’ve ever seen. Where we drove by it, the afternoon sun passed through it for a beautiful light display.
When we got home, we still had a few hours of daylight left, and Jason has been begging to go swimming for several days, so we all donned our swimsuits to walk down to the lake.
Did I mention we could walk across the street to get to the lake, and it was beautiful? Yeah.
It turns out that high hopes and warm air do not a warm lake make. Lake Geneva was quite cold as the sun was setting, nor was there a gently sloping beach to slowly wade in on. The shore was made out of boulders, like a pier. You had to stand on a boulder and build up the courage to step to the next boulder down, where you would quickly die of cold water shock (as we learned from an especially morbid restaurant menu in London).
Slowly, but surely, we all managed to go all the way in, even with the hair in. I was able to float on my back, so I didn’t have to tread freezing water.
It wasn’t all that cold, maybe 20 degrees C. We splashed around for a bit, dunking each other and trying to convince Jason there were sharks (freshwater sharks) in the lake.
I eventually got cold, so I got out and threw sticks for Jason to fetch.
Eventually we wandered over to meet a shorecat and his fisherman.
All told, a good last day in Montreux.