Nobel dreams

The book Nobel Dreams by Gary Taubes is a good description of some of the characters in the UA1 experiment, most notably Carlo Rubbia. I worked on it for a while as a postdoc for David Cline, but didn't get to know as many people as Gary did in a much shorter time.

Both Carlo and David had their sights on a Nobel prize; Carlo got to share one and David didn't.

I remember sitting at the next table over from the two, eavesdropping on them batting ideas back and forth--it was a joy to listen to. They weren't quite such joys to work for, though.

During one of his brief visits to Madison he collared his two postdocs and grad student for instructions. In five minutes he gave me no less than three "absolute top priority" tasks. My better half is less enthused with him. He wanted me to go to a conference in LA and was nonplussed when I pointed out that that was my wife's due date. A few weeks later we had car trouble and my wife came to fetch me at Fermilab, where she met the good professor for the first time. He greeted her with a grumpy "You don't look nine months pregnant."

A colleague says that DOE should fund Cline to just travel around like a bee to pollinate groups with ideas like a traveling conference meeting. His presentations were enthusiastic, expansive, and whirlwind; he could go through a dozen slides in a minute. If talking about his own team's work he had a tendency to overstate accomplishments. . .

At any rate he left Wisconsin for greener pastures at UCLA, and seems to have devoted more time to novel accelerator technologies. His team announced pictures demonstrating that a laser could be used to accelerate electrons. The novelty here is that the laser has to be carefully focused, and that they have some pictures from the Brookhaven facility to prove it works. (An out-of-the-box laser beam has locally strong electric fields, but the push and pull cancel out. You have to play various tricks to take advantage of the available force, and Lawson and Woodward(*) seem to have proved that most of the tricks don't work.)

The laser was about 3 Joules dumped in a beam spot of 50μ. They saw electron accelerations of up to 20MeV, which is good and energetic.

It is nice to see this. It is a long way from being usable for normal particle accelerators--if indeed it is ever possible. The spread of energies is too large. Cline suggests using electrons accelerated by lasers to heat/compress pellets of hydrogen for fusion. Current methods being tried include using focused lasers to superheat the outer shell to create a shock wave to compress the rest of the pellet, capturing laser energy in a cavity to ditto, and so on. I'd not think electron beams would transfer momentum as well as ions, but there might be other effects--I've been wrong before.

The pictures are a little hard to understand without some explanation. The electrons went into a strong magnetic field where their trajectories bent. The faster electrons had straighter paths, the slower ones more curved. When they came out the other side they hit a detector, and the numbers of hits were counted up. The pictures are oriented such that slower electrons would be bent more and wind up at the top of the picture and faster ones be bent less and wind up nearer the bottom. The right hand pictures show more hits near the bottom: faster electrons.

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(*) Never heard of them before: I haven't worked on laser acceleration and I've only a vague acquaintance with plasma wake field acceleration.