by Jim Schultz

Stay in a kitchen long enough, say champion chefs, and you'll realize that meal preparation is as grueling as any intense sporting event.

The same goes for conducting a physics experiment at a major research facility: staff and users must be mentally and physically prepared, equipment must be in place, and an exceedingly complex effort must be efficiently coordinated and managed.

Orchestrating a large banquet can, however, result in a kitchen too crowded to accommodate the chefs, assorted kitchen help and the wait staff. At JLab, user interest has created a similar dilemma. The Lab's administrative complex is simply running out of room.

"Space is a major issue here," says Karen Hokansson, the Laboratory's User Liaison Manager. "We have 381 users assigned space on a permanent basis, with 225 here on any given day, plus at least two dozen outstanding requests for space. During the summer space is a nightmare because you get all the post-docs and a slew of graduate students. It's definitely a challenge."

Fortunately, help is on the way. Room has been made available for the Lab's Accelerator Division next door at the new Applied Research Center, and the Theory Group is slated to move within the next year or so. Once the relocations occur, a number of CEBAF Center offices will be freed, integrating experiment teams and Physics Division staff.

Despite the space crunch, researchers conducting experiments at Jefferson Lab can expect a warm logistical welcome. Although each research team must arrange its own lodging with assistance from User Liaison, the Lab provides work space, accelerator-related equipment and services, labor (for equipment setup and tear-down), data analysis, long distance telephone service, desk supplies, Xeroxing and videoconferencing services. Groups often bring in additional funding, from the National Science Foundation or the Department of Energy, for supplies, equipment purchases (such as specially designed devices for experiments or high-end workstations) and to support other expenses not generally underwritten by the Lab.

In the Kitchen

Despite all of the assistance, physical arrangement of an experiment in any of the Laboratory's three halls remains the most time-intensive element of the research process. Setup can last several weeks or even months, depending on the particular hall and the desired configuration of detection devices that track outcomes of the subatomic collisions occurring during a given experiment. Specialists must also make sure researchers are using the right "trigger:" custom software that instructs monitoring computers how and when to record particle-detection events deemed significant.

At the heart of every experiment is an analysis of the subatomic debris generated by the high-energy collisions between the accelerator's electron beam and a target material usually comprised of supercooled, liquefied hydrogen or ammonia gas. Although the target is relatively minuscule, at two cubic centimeters in size, it requires precise and constant cooling from room-size refrigeration apparatus.

"Setting up an experiment involves a number of tasks: controls, computers, targets. It gets pretty wild," says Hall B beamline coordinator Arne Freyberger. "The crucial thing is scheduling and preparation. The better organized you are, the smoother everything runs."

Once a team of a dozen or so Lab technicians have completed equipment and target installation, the experiment begins. Electron beam is funneled to the experimental hall, a process intended to continue without interruption 24 hours a day for the experiment's duration. In practical terms, Freyberger says that because of the complexity of the systems and subsystems supporting accelerator operation, constant beam delivery is not yet possible. "We often achieve pretty good efficiency," he says. "But, we are still debugging a number of systems. With a bit more time and manpower we'll get it straightened out. We're getting there."

Cooking gets underway

As the experiment proceeds, a monitoring center known as the "Counting House" becomes home to those overseeing the experiment's progress. Graduate students normally draw this assignment which, like the experiment itself, is an around-the-clock job. Moreover, at least a dozen experts/troubleshooters - experiment team members as well as personnel from the Lab - are on constant call for as long as the experiment is up and running.

Preparing the users for their experiment's run is a difficult and complicated task. "What you try to present to the people in the Counting House is something that makes it easy for them to know the status of their experiment," Freyberger says. "If you suddenly start getting paged a lot, you may realize your system isn't very user friendly, your documentation isn't as good as you assumed and your [software] code isn't as bug-free as you thought. So you work doubly hard to improve all of those things."

After weeks or months an experiment runs its course. The work in the physics "kitchen" is done. The "feast" - data from the investigation - must now be digested and analyzed. How will the physics "meal" be served? Will it be perfectly cooked? In fact, it may not be what was ordered, or even what appeared on the menu.

Find out what happens in The Feast Enjoyed: Part Three of Physics Well Done to be published in next month's On Target. decided that we as individuals could make a contribution..."

Part One: Mastering the menu (or how to get an experiment cooking!)

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