When an experiment takes a decade to build, or involves more than a couple hundred people, or the people are spread out over wide areas, understanding is lost.
When I was a graduate student, it was still quite common for a student to build part of the apparatus, write or help write the software for unpacking the data, and do analysis and simulation.
Now the subdetectors are generally too big for one person to build, and so you need engineers and a team of technicians and an experienced supervisor (at least I hope you get one!), and it takes several years to do.
So what does the graduate student do? Write software. Simulations, analysis, monitoring, sometimes data acquisition. It has been startling to see some of the reports students present at the local group meeting. Their professors are experienced and on the ball, and correct them appropriately, fortunately; but most of the students had no feeling for what noise and failures would do to their ideal projections ("find a Z-prime signal in the first month"). A week or two with a prototype chamber and readout would give them a lively distrust for the answers computers come up with.
And, of course, the time to build takes so long that it now takes several generations of graduate students before they start seeing real data—and the unlucky ones have to find something to write up for a dissertation in the meantime. Something is missing when students only sample the output end of experiment. I know it seems ideal: come up with an idea, somebody else funds it, builds it, runs it, and you get to just analyze the results. Still, the friction tells you something important.
I do not know why it is so, but you share much more information face to face than over a video link, and of course far more than with email exchanges. There is no substitute for sitting down in the same room with a colleague and a sheaf of notes and maybe a laptop or two to show diagrams on.
My colleagues are on several continents. Just the trip from Wisconsin to Fermilab is an impediment to real ease of communication; being in different time zones cuts hard into the sharing. The rule has always been that the experiment site/headquarters is the place to be.
I’m glad CERN’s wireless service in the cafeteria is slow. It has always been a famous place to talk and learn, and frequently much better than the Powerpoint presentations in the working groups, and it is sad to see people hunched in isolation.
In the working group meetings, everyone has a laptop. Some with less than spectacular eyesight, or with some question about one slide or another, are reading the presenter’s slides. Many are answering email or writing presentations of their own, or some analysis project. Some I’ve seen buying airline tickets, reading the news, and the grad students often read online comics (amazing what you can see from the back of the room). Rarely are the presentations self-contained—they are almost invariably updates on existing work. If you show up as a newbie you will be at sea for the first few meetings.
And that is a serious problem. Because experiments like CMS are so large you need many teams of people to manage the subdetectors and figure out how to process the data and work around the problems. So typically a scientist will be an expert on one aspect of one or two subdetectors, and have only a general notion of how the others are performing. It doesn’t help to show up at meetings for the other working groups—there aren’t enough hours in the day, and they don’t have time to explain everything from scratch at every meeting. CMS has tried to deal with this by selecting people whose job is to communicate to other subgroups—but it really helps if you are at CERN. And most of us aren’t. (Especially not me after that last budget cut. And the Tevatron shuts down 1-Oct unless it breaks early.)
IceCube had a collaboration meeting/inaugural celebration this week. They’d finished drilling and installing all 86 strings of detectors in Antarctica, and everybody was happy. I found the plenary talks wonderful—they explained what was going on, and the meaning of the historical datasets that I’m trying to get into the data warehouse, and what they’d been trying to do and were planning to do next. Reeder noted that it was quite an accomplishment to build such a large detector and have the top people all still speaking to each other, and apparently still liking each other. And on time and on budget.
Halzen had a wild idea, and enthusiasm and drive and a skill for explaining what it was about to funders, politicians, and the man in the street—and now the largest detector in the world is buried in the ice and being used to attack dozens of questions. OK, it will take years of data collection to detect some of the types of signals they want, unless a star in our galaxy decides to cooperate and go supernova for us, and there are still no unambiguous extraterrestrial neutrinos. But still.
The place to be is not the South Pole (although most folk want to have been there—except Halzen himself). I don’t know yet if there is a center—I’ll learn more as I work here. Germany, Sweden, Belgium, New Zealand, USA? I wonder what difference it will make to be so decentralized. Perhaps the apparently somewhat laissez faire physics coordination comes from being a distributed culture.
No comments:
Post a Comment