Small Universe (JMU Magazine)

Dr. Kevin Giovanetti rides the lift above the detector.

Small Universe

Throwing Subatomic Baseballs

By Margie Shetterly, JMU Magazine
photos by Doug Sesny

Through his work with the Thomas Jefferson National Accelerator Facility in Newport News, Va., JMU physics professor Kevin Giovanetti has given his students a chance to be in on the ground floor of a state-of-the-art national research facility. He also has provided students with hands-on experience in problem solving, working side by side with some of the top physicists in the world.

It's an opportunity senior Justin Voshell describes as an "immersion experience – much like going to a foreign country. Here's a place with 1,000 geniuses, and you get to ask questions for free.

"The best thing that comes out of it is seeing the level of work" being conducted at the Continuous Electron Beam Accelerator Facility at the Jefferson Lab, Voshell says. That, in turn, puts the textbook material he has learned in classes into context and gives it relevance. "A lab like this gives you a reason to learn the physics," he says.

For approximately 20 JMU undergraduates, CEBAF has been that off-campus lab – a state-of-the-art particle accelerator where students combine theory with practicality and learn that applied physics is really an interdisciplinary exercise.

Giovanetti's involvement in the $554 million project dates to the late 1980s, during the conceptual and design phase of CEBAF. Last summer, he and five JMU students helping with his project finished the construction and installation phase of their calibration system. Then in the fall, they started final testing and collecting data from experiments.

Giovanetti's work centers on the huge electromagnetic calorimeter in Experimental Hall B, a detector that records what happens when, for example, a speeding electron strikes it. "It's like a bullet fired into a block of wood," Giovanetti explains. "The energy from the bullet is transferred to the block of wood, and most of that energy shows up as heat energy." In the case of CEBAF experiments, the bullet is a scattered electron or another subatomic particle and the block of wood is the detectors.

Giovanetti's main responsibility at CEBAF has been to design and install the calibration system for the calorimeter so that it can accurately measure the energy given off when the particles collide and what changes happen to those particles. Included in that calibration is the design and installation of a laser with a fiber-optic distribution system and computer-controlled slit patterns. This system, which directs light to specific elements in the detector, monitors the response of critical components.

His secondary responsibilities have included testing the whole calorimeter, assisting in running experiments, helping with data analysis and planning experiments. Voshell, who is double majoring in physics and mathematics, has been focusing on the mechanical aspects of the calibration system. One particular concern was building in safeguards to prevent damage when remotely moving the slit patterns. He also wired the entire device, which includes hundreds of different wire connections. The work, both painstaking and crucial, mirrors the entire CEBAF operation. "Millions of things have to go right each time," Voshell says.

Voshell describes his work as "almost more of an engineering problem," – making mechanical parts work and interface with the computer at CEBAF. In that respect, CEBAF research reflects much that's typical in the field. "It's far more than physics," Voshell says. It also encompasses "all these things you have to learn to do well to be able to do the physics." Someone who excels in the field of physics "is not just this guy that knows Newton's laws," Voshell notes. Rather, training involves combining expertise in a number of disciplines. "Physics is simultaneously the most theoretical and most applied of the sciences."

Jefferson Lab Continuous Electron Beam Accelerator Facility

An electron "gun" (A) sends a continuous beam of electrons at near-light speed into an injector, which increases the beam's speed and directs it into a three-quarter-mile "track."

The beam makes laps around the track through two accelerators, which again increase the speed, until the beam reaches maximum energy (4 GeV). Then the beam and its electrons divert to three experimental halls. JMU activity occurs in Hall B.