The scene evokes visions from a video arcade. A monotone computer-generated voice utters occasional phrases in technical jargon-”P bar bunch four injected”-and various colored lines on a video graph dance on the screen. Musical computer tones sound as physicists clad in denim and flannel cheer.
”Go higher! Push, push!” urges George Brandenberg, a Harvard physicist who serves as captain of the night-owl shift at Fermi National Accelerator Laboratory, in Batavia.
This is the home of Tevatron, the world`s most powerful atom smasher, an arcane world where high-energy physicists work round the clock to explore nature`s secrets. While other night-shift workers flip hamburgers, chase criminals or change IV tubes, these workers monitor an invisible drama whose high-speed players may ultimately explain the workings of the universe. Still, in many ways, it`s an oddly ordinary scene, far from the visions of frenetic white-lab-coated scientists popularized on screen. It is a world where, as one physicist put it, ”Boring is beautiful.”
Shortly after 2 a.m., computer messages announce that the beams are running, and the shift on an experiment called CDF begins recording data on magnetic tape. Tim Hessing, a Texas A & M physicist who serves as shift
”ace,” the main troubleshooter, puts his feet up and takes a swig from his Pepsi as Brandenberg begins cutting up computer printouts and putting pieces into the logbook using Scotch tape.
”Really, the captain`s job is mostly done with scissors,” he jokes.
”I`m also good at making paper dolls.”
For the first time in 10 hours, there is a sense of accomplishment because the experiment is running and information is being gathered. Since about 4 o`clock the previous afternoon, frustration ruled the control room. Despite the air of activity from a continual hum of fans cooling electronic equipment, absolutely nothing was happening: The beams of protons and their negatively charged anti-matter counterparts, called ”proton bars” or ”p-bars,” that Tevatron makes weren`t running.
These beams are designed to smash protons and p-bars into each other inside detectors where the collisions convert energy to matter. By measuring collision products and how they travel, physicists piece together what happens in the subatomic world they have never seen directly.
The beams are assembled and held in place inside Fermilab`s 4-mile race track by magnetic fields created by state-of-the-art electro-magnets that are kept frozen at temperatures approaching minus 460 degrees Fahrenheit-absolute zero-so that they become superconductors, losing all resistance to the flow of electricity.
Any glitch in the 1,000 superconducting magnets or in their elaborate liquid helium cooling system can cause a shutdown of Tevatron for repairs. Even something as slight as a wrench dropped onto the system by an errant workman can kill the beam.
All through the evening, scientists kept hoping that Tevatron`s beams would start running again, at least by midnight, so the time spent by the swing shift wouldn`t be a total waste.
As they wait for something to happen, physicists amuse themselves by reading computer printouts, checking program software, sipping coffee and watching digital announcements on some of the 55 cathode ray screens displayed around the CDF control room.
Shortly after 11 p.m., a physicist watching computer data on a screen yells, ”There`s a quench!” meaning one of the superconducting magnets has heated to the point where it has ”gone normal” and doesn`t conduct electricity without resistance anymore. It is now clear that nothing will happen until after midnight, when the night-owl shift runs things.
”Typically what happens is that something goes wrong-say, the computers die-and we work all through our shift and get it fixed so the next shift can take lots of data,” said Brenna Flaugher, a Rutgers University graduate student who serves as ace on the swing shift.
When the beam isn`t up, she explains, there`s just not much to do but watch and wait because ”it`s out of our hands.”
Each shift`s immediate goal is recording on magnetic tape as much electronic computer data describing subatomic collisions as possible for analysis later. Since last fall, CDF team has made about 2,800 such tapes, each running about 20 minutes and containing evidence from some 1,500 collisions.
”When it`s all going smoothly, it`s kind of boring, but it has a good feel to it,” said Flaugher.
The basic work of particle physics has always been about as tedious as pitting cherries or sorting soda bottles.
Now that things are highly automated, the physicists spend a lot of time babysitting balky computers and temperamental equipment. But, tedious as that may be, it beats the way physics used to work.
It was back in the `50s, when a physicist who`d been studying his glass of beer got the idea for the bubble chamber, a container filled with liquid hydrogen kept just below its boiling point.
Into this cold liquid hydrogen scientists shot the newly created subatomic particles their experiments produced, and these charged particles left trails of bubbles in the liquid as they passed through. With the aid of light flashes and photographic plates, scientists made images of those bubble trails.
This process turned out stacks and stacks of pictures daily requiring analysis by scientists eager to identify new particles and deduce their properties. But looking at thousands of bubbly pictures for hours at a time was enough to make a person go blind, or crazy, the scientists discovered.
Soon senior physicists decided this was something they could delegate to junior colleagues, and before long the job was downgraded further to a graduate student task.
Eventually it fell to undergraduates, and finally it was determined that a person didn`t really have to know physics at all to spot the odd bubble photo and pull it out of the mass for referral to a physicist. People unskilled in physics, many of them housewives, were hired as scanners and given frequent breaks from the scanners` room to rest their eyes.
At Fermilab, the bubble chambers are gone, and computers have replaced the housewives, but researchers still must watch their machines to assure everything is working correctly. This isn`t a task they can delegate to day laborers.
Capturing particle physics data has been compared to tracing footprints of dew in the mist, but it actually is not as concrete as that, so the apparatus must be extremely sensitive in order to work.
At Fermilab, early on a cold morning in February, two of the owl shift physicists, Eric Pare from Paris and Mike Levy from the Lawrence Berkeley Laboratory in California, were watching computer screens to assure that selected events displayed appeared to make sense.
”We enjoy this,” Levy assured a visitor. ”It may not look like it, but for us, this is fun.”
These physicists have helped design and build the large assortment of equipment that comprise the detector, and they tend to regard making detectors as half the fun, said Brandenberg, the shift captain.
”If this was just a collection of equipment we bought someplace, it wouldn`t be nearly as interesting for us to watch it run,” Brandenberg said. In this context, ”boring is beautiful” because it means things are going smoothly, he said. ”We don`t want any excitement.”
But on this morning, boredom was a scarce commodity. About 4:45, Hessing noticed that a computer screen indicated an overload of data was coming into the system while Brandenberg noticed that the tape reels themselves were motionless: Nothing was actually being recorded.
Apparently, an individual computer board went ”hot.” Like a gas pedal stuck to the floorboard, it got jammed on full tilt, accepting all data indiscriminately. In response, the rest of the system shut off.
After turning off the computers, it was decided to reload the program, altering instructions so the rest of the system could ignore the hot board. Yet when Hessing started a new run sometime after 5:30 a.m., nothing happened. ”What`s going on, did we blow a fuse?” asked Brandenberg as the physicists headed for the computer room next door to look. Brandenberg telephoned a University of Chicago graduate student to ask advice.
After asking a few questions, the sleepy student suggested they try reloading the software in the computer again. They did, and at 6 a.m. it worked.
”We`ll discuss this at our daily staff meeting this morning,” said Brandenberg. ”Who knows what was wrong. Could be a software error. But it has the earmarks of a temperamental system.”
And for a few hours, the search for the ultimate nature of the universe settles into a welcome boredom again.
