


FLATOW: This is Talk of the Nation: Science Friday, I'm Ira Flatow. After a much anticipated and seemingly successful test, the particles came to a screeching halt last week at the Large Hadron Collider. It appears that the super-cold helium used to chill the magnets, sprung a leak.

Things had to be shut down for repairs, and it might be a while before the particle smasher is fired up again. And we start getting some answers to those burning questions about the origins of the universe. Joining me now to tell us about what went on is Dan How - Hooper.

Dan is the assistant professor at the University of Chicago. Dr. Hooper is also an associate scientist at FermiLab in the National Laboratory in Batavia, New York, and out - Batavia, Illinois, outside Chicago. His book is called " Nature's Blueprint: Supersymmetry and the Search for a Unified Theory of Matter and Force," Welcome back to Science Friday, Dr. Hooper.

Dr. DAN HOOPER (Assistant Professor at the University of Chicago; Author, "Nature's Blueprint Supersymmetry and a Search a Unified Theory of Matter and Force."): Well, thanks for having me on again.

FLATOW: Sorry my mouth is not working so well this afternoon.

Dr. HOOPER: No problem.

FLATOW: It must be getting chilled by all that helium. What happened? Did the helium leak out? Is that what happened?

Dr. HOOPER: Well, yeah, around September 19th or so, some repairs were being finalized on one of the large transformers at the LHC. There was some sort of faulty electro connection, so it seems, and this seems to have caused about a ton of the liquid helium to leak, and for parts of the detector, the parts for the accelerator, that heat up and the magnets have some malfunctions as well.

FLATOW: Mm-hm. And so why is it going to take so long to put this back on line, they were talking about months?

Dr. HOOPER: Well, the thing is, the reason we use liquid helium is to keep the accelerator very, very cold. So we want it to be around two degrees above absolute zero. FLATOW: Mm-hm.

Dr. HOOPER: And to work on it, it has to be at roughly room temperature, which is you know, hundreds of degrees higher. So it takes about a month simply to heat up the detector to room temperature, or rather the accelerator-room temperature, so it can be worked on. And then it will take some time to actually do the maintenance and the work, and then it takes another month to cool it down to liquid-helium kind of temperatures.

So we're now instead of looking at late in 2009, we're looking at maybe March or April of - and I'm sorry - instead of late 2008, they're looking at March or April in 2009, before they start getting full-energy collisions.

FLATOW: Were any of the parts damaged that would need to be replaced?

Dr. HOOPER: Well, not all of the answers are in yet. It's going to take the next month before it's warmed up, and they can go in it and really learn all those things in detail. But yes, some of the magnets are almost certainly damaged, and some of the electronics as well.

FLATOW: Mm-hm. Do they...

Dr. HOOPER: But nothing that can't be repaired.

FLATOW: Yeah, I guess...

Dr. HOOPER: This is a relatively small part of the accelerator, and you know it's - we've been building this thing for, well, 10 years of construction...


Dr. HOOPER: And 20 years of R&D, and 30 years of just thinking about such a machine.

FLATOW: Right.

Dr. HOOPER: This is just a few months in that long path.

FLATOW: They actually had turned the machine on for a test and had gotten some results, hadn't they, on this?

Dr. HOOPER: Well, the first day or so was very successful. So, on September 10th I was at FermiLab with a few hundred physicists watching the experiment turn on in the middle of the night. And it took, you know, in the matter of a few hours they had beams of protons going in both directions around the 17-mile track of the experiment.

It was very successful. It exceeded all expectations. But then shortly after that they had the first problem with the transformer that happened, and a week or so later the problems with the magnets and the helium.

FLATOW: Mm. And how much do you think it's going to cost to fix all of this stuff?

Dr. HOOPER: Well, I'm not really sure how to put it - how to estimate the dollars on this. I haven't heard any one make such an estimate. But it is a small fraction of the cost of the experiment. Like I said, this is something that talk - that took deca - more than a decade to construct, and 20 years to design.

So, you know, what the cost of having these scientists work on it another six months before it's up and running, I think are quiet small. And also these are sorts of - the sort of problems that you expect in a huge prototype-like experiment like the LHC that to have - you know, no one's ever built a machine like this.

FLATOW: Mm-hm.

Dr. HOOPER: You expect a machine like this to have problems, you know, growing pains as you get it to work operationally.

FLATOW: Right. Question from Second Life from Rudy He asks, will it come back on line before power must be diverted to keep the cities there warm? Because it uses a lot of juice, doesn't it?

Dr HOOPER: Well, that's right. And as I understand they have an arrangement with the city of Geneva where they have scheduled shutdowns in the winter to conserve on energy. But the schedule now is actually - now is that they hope to bring it online in late March, which, you know, the winter will be largely over by then.

FLATOW: Mm-hm. And so you just have to sit back and wait. You must be very disappointed, I would think, and along with a lot of other scientists.

Dr. HOOPER: Well, you know, we would love to see data coming in sooner than that, but you know, I've been waiting a long time for this. Six months isn't going to kill me or anyone else.

FLATOW: All right. Thank you, Dan, for taking your time to be with us, and I hope you have a short winter.

Dr. HOOPER: Sure. Thanks for having me on.

FLATOW: Dan Hooper is assistant professor at the University of Chicago, author of " Nature's Blueprint: Supersymmetry and the Search for a Unified Theory of Matter and Force."






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