Helping scientists understand the working of the universe

Author: Carol C. Bradley

Particle accelerator installation

Physics professor Michael Wiescher is interested in the origin of the elements in the chemical evolution of the universe, and a new particle accelerator that began operations this month in Nieuwland Hall of Science will advance that research. “We try to simulate the reactions that take place in stars,” he says.

Our bodies, he notes, are 70 percent hydrogen—50 percent of which was formed 12 billion to 13 billion years ago in the Big Bang, and the rest formed in subsequent generations of stars.

“You have a direct personal connection,” Wiescher says. “Half of the atoms in your body have been part of supernova explosions of stars.”

The new particle accelerator—housed in a special high-density concrete tower as a radiation shield—was funded by the National Science Foundation (NSF) and represents a major equipment upgrade for the University. It’s the first accelerator the NSF has funded in nuclear physics since the 1980s.

Michael Wiescher Wiescher

The 15-ton accelerator, built in Wisconsin by National Electrostatics Corp., can generate voltages as high as 5 million volts and can accelerate a wide range of different beams for use on various experiments of interest to researchers from Notre Dame’s Nuclear Science Laboratory.

The department includes five faculty members, a research staff of about 20 and an average of 25 graduate students.

The accelerator will be used primarily to expand the research program at the University’s Joint Institute for Nuclear Astrophysics, which Wiescher directs, and the Institute for Structure and Nuclear Astrophysics.

Cleaning the accelerator

The accelerator will provide beams to the St. George Recoil Separator, installed last year, that can find a single particle created by an alpha capture reaction from 1,015 beam particles. The University’s nuclear astrophysics program, started in the mid-1980s, is one of the leading global centers, attracting user groups from 20 to 30 countries.

The new accelerator will help scientists gain a better understanding of how the universe works, says Ed Stech, associate professional specialist in physics. “It’s basic physics research—and we’re one of the few university-based labs like this left. Our students are trained to go into industry, academia and the national labs.”

Testing of the accelerator has begun, and initial experiments will be conducted over the summer.

Photos:

At top, the new particle accelerator, shown here being lifted into position on top of Nieuwland Hall of Science, is 21 feet tall, about eight feet in diameter and weighs nearly 18,000 pounds.

Below: Postdoc Dan Robertson and graduate student Stephanie Lyons work on the final cleaning of the hoops inside the accelerator, in preparation for closing the tank. Air will be pumped out and the tank filled with sulfur hexafluoride (SF6), an inert gas that will allow the maintenance of a stable 5 million volts.