by Tom Parisi
It’s one of the biggest and most ambitious science experiments ever, and NIU graduate students Rob Calkins and Chad Suhr are in the thick of it.
After more than a year of repairs, scientists recently restarted the Large Hadron Collider (LHC) at the CERN research facility near Geneva, Switzerland. CERN is the world’s largest particle physics laboratory.
And the LHC is the most powerful particle accelerator on the planet, built to smash protons moving at nearly the speed of light into each other and so recreate conditions a fraction of a second after the big bang.
It took decades of planning and the know-how of thousands of the world’s top scientists and engineers to build the LHC – at a cost of about $9 billion. The result is a one-of-a-kind “discovery machine” that is expected to shed light on the fundamental forces of nature, perhaps unlock the mystery of dark matter and help us better understand the origin and evolution of the universe.
Calkins, 27, of Naperville, and Suhr, 29, of Canyon, Texas, are both working toward their doctorate degrees in physics at NIU. They’re also part of an NIU group of faculty and research scientists who are contributing to the ATLAS experiment at CERN, where the two have been working since January.
“It’s interesting to do something no one has done before,” Calkins says. “The job is a constant challenge. There is always a new problem to solve.”
In all, an estimated 10,000 people from 60 countries have helped design and build the LHC and its four massive particle detectors, including more than 1,700 scientists, engineers, students and technicians from 97 U.S. universities and laboratories.
The LHC infrastructure includes a 17-mile underground circular tunnel that stretches between the Jura Mountains and Lake Geneva, near the French-Swiss border. The particle accelerator was first switched on in 2008 but had to be shut down because of a faulty electrical connection that resulted in equipment damage.
Particle beams once again started zooming around the LHC on Nov. 20.
Calkins and Suhr came to CERN via different paths. Calkins had enrolled in NIU’s Ph.D. program, anticipating that he’d be working on NIU collaborations at Fermi National Accelerator Laboratory. Suhr completed a master’s degree in philosophy at NIU, decided to take some additional physics classes and met Professor Dhiman Chakraborty, who heads up the NIU contingent of the ATLAS team.
“He asked if I wanted to work on this project,” Suhr recalls. “It was a pretty natural consequence of this that I’d spend some time at CERN, but I hadn’t really anticipated moving here for multiple years.”
Over the past two decades, NIU’s High-Energy Physics Group has established a strong track record of world-class research in experimental particle physics. NIU faculty and students have made significant contributions to the DZero project at Fermilab’s Tevatron collider and to research and development for future facilities under consideration, such as the International Linear Collider.
”Our involvement in the LHC was a natural progression,” Chakraborty says. “Particularly for our students, it’s a wonderful opportunity to be conducting research at the very frontier of physics. Scientists can and do contribute remotely to the LHC experiments, but for young collaborators, there is no substitute for being there.
“We’re very happy with the performance of Rob and Chad, who are making significant contributions,” Chakraborty adds. “It’s a win-win situation for everyone involved – the students, the university and the ATLAS collaboration.”
Calkins and Suhr trained at Argonne National Laboratory before being deployed to CERN. They join more than 2,000 scientists and engineers who are collaborating on ATLAS, one of two general-purpose LHC particle detectors.
The particle detectors could be likened to highly sophisticated, gigantic microscopes, able to peer into and take pictures of sub-nuclear interactions. The entire ATLAS detector system has an area equal to three football fields, consisting of 100 million independent electronic channels. As charged particles pass through a magnetic field created by superconducting magnets, the detector has the ability to accurately track them to the precision of the width of a human hair.
Calkins and Suhr are among the scientists who are responsible for calibrating and monitoring an important part of the detector, called the tile calorimeter, to ensure that it produces high-quality data reliably and consistently. This counts as a “service task” that each member of the collaboration must perform in order to earn the privilege of analyzing the data collected by the experiment. The NIU Ph.D. students also are engaged in developing analysis strategies and tools for studies of the top quark.
Both Suhr and Calkins enjoy the CERN atmosphere.
“I like the international scene at CERN,” Calkins says. “I work with people from all over the world and get to learn about their cultures and politics. I’ve also gotten to teach a few people the basic rules of baseball.”
Suhr says he loves learning new physics from some of the world’s top thinkers.
“There are a lot of people to learn from and interact with, so the community aspect can be very rewarding,” Suhr says, adding that people are interested in his work no matter where he goes.
“Before I moved out here I was able to spend a day at a high school talking to students about the LHC,” he says. “The students were very engaged, and it was a great opportunity to help them understand what we’re doing here and a little bit about how science works.”
Other NIU members of the ATLAS team include Professor Gerald Blazey, research scientists Guilherme Lima, Vishnu Zutshi and Sergey Uzunyan. The team likely will expand from seven to 10 people over the next two years.