Thursday, August 25, 2005

Cool it!

The last time I interviewed Ben Kilminster, the young physicist who's in the rock band, he was wearing a "Bad Mo Fo" T-shirt and talking big about Fermilab's chances to find the Higgs boson.

Originally uploaded by 137 Films.

Possibly he was swaggering a little, since he was about an hour from the big rock show at the Fermilab User's Center where he would be the lead singer, compelling a dance floor full of young, blonde physicists from South America to start shakin' it up. It was great for the camera. He said something like "if we find it, we'll be right on the edge. We might be able to grab the steak just as the Europeans are about to throw it on the grill." A great metaphor.

So, other than impending stardom, what had gotten Ben so fiesty? Why was he suddenly a little more confident in the aging Tevatron's ability to find the Higgs?

He mentioned that electron cooling, something experimental and in the works on the other side of the Fermilab grounds for about 10 years now, had kicked in and was having an effect. If all went well, this would double Fermilab's luminosity (remember, that's essentially the number of collisions they can create --- how many atoms they smash together. The more atoms that get smashed, the more chances they have to find something). Let me say that again: it would DOUBLE the chances to find something. That's pretty big.

How would it do this?

A month or two ago, we were hanging out with John Conway in the detector control room. There was a little black and white monitor that he said they keep checking all day. Essentially, there were two numbers they checked on. One number was the amount of protons, and the other number was the amount of anti-protons.

Why are these numbers so important? Because protons and anti-protons are the things that the Tevatron smashes together. These are the "atoms" in "Atom-Smasher". There's only one problem: the Tevatron can make all the protons it could ever need. They're cheap and easy (as Leon Lederman said, you just go down to Ace Hardware and buy a bottle of Hydrogen, send it through a spark, and you've got protons galore). Remember the cockroft_walton? That great-looking machine that looks like it came from the pages of a Flash Gordon comic book? That's where they make the protons.

But --- making anti-protons is very tough, and it's even tougher to keep them around. Imagine that you're got a reality TV show that features red and blue cars smashing together in the desert. You've got plenty of red cars, but for some reason the blue cars are extremely difficult to make. So you've got lots of red car drivers sitting around, just waiting for a blue car to show up so they can smash into it. Not very efficient. You're starting to lose a lot of viewers to "Survivor."

Electron cooling is like an invention that allows twice as many blue cars to roll out of the factory. Suddenly you can smash twice as many cars in the desert! Ratings soar! Electron cooling can double the amount of anti-protons, thereby doubling the amount of atom smashes that take place in the tevatron. That's good news --- with twice as many collisions come twice as much data, and twice the chances to make a discovery. That's why Ben was exhibiting a little bravado that day before his big rock show.

So Monica and I went down to talk to the guy who had been in charge of this process for ten years --- Sergei Naigetsev. He took us over to the place where the electron cooling happened --- it's a small building with a big tall cylinder inside. The short version of how it works is that they cool the rowdy anti-protons with a calming, sensible beam of electrons. Once they are cooled off a little, they are easier to manage and last longer, and can get packed into the tevatron tighter. We got some nice shots, and he told the story about how he was on a camping trip when the process was officially proven. He was scrambling around on a sand dune with his cell phone, trying to get a signal, heart pounding with the news. That's a nice image.

1 comment:

Professor said...

Yeah! New Post! Great analogies! I'm really looking forward to hearing more about Fermilab and seeing the finished doc.