When Chris Colvin and Tony Losada boarded a flight to Rome in June, it was the culmination of a nearly yearlong project in particle detection at the Thomas Jefferson National Accelerator Facility (JLab), in Newport News, Va., in conjunction with scientists at the Instituto Nazionale di Fisica Nucleare (INFN) in Frascati, Italy. Colvin and Losada, both senior applied physics majors, are part of a team building a RICH detector – a ring-imaging Cherenkov detector – that can determine the velocity of charged subatomic particles.
Colvin got involved with the project, which is funded by a grant from the National Science Foundation, last year while working at JLab under the direction of Dr. Fatiha Benmokhtar, a former CNU physics professor who is now visiting assistant professor of physics at Duquesne University. Colvin’s task was to build gas electron multipliers (GEMs), which are used in conjunction with light detectors as components of the RICH apparatus. Losada joined later as a software expert, programming the GEMs and light detectors. The findings from the project will ultimately be used in diagnostic work, as Losada says: “These detectors [will be] put on the beam line at JLab and used in other experiments so [researchers] can get better, more accurate results.”
Losada explains that when a beam of charged particles passes through a material called aerogel – a gel in which the liquid component has been replaced with a gas – a cone of light is emitted. “Using the GEM to tell where the cone is pointing, and the light detector to detect how big the cone is, we can tell you what type of particle it is,” he says.
Approving of Colvin and Losada’s preliminary work, Benmokhtar arranged a lunch meeting for them with Dr. Patrizia Rossi, then a senior scientist with INFN. She is now deputy associate director for nuclear physics at JLab. “[Dr. Rossi] decided we were a perfect fit and there was no question that we should be the ones working on the project, to go to Italy and see it through to the end,” Losada says. He and Colvin began weekly teleconferences with the INFN and JLab teams to discuss the experiment and plan their trip to Italy. Colvin, as the hardware expert, was responsible for assembling the GEMs (pictured above), while Losada wrote software to interpret the results. While each had his area of specialization, both had to be familiar with the others’ work if asked by the INFN scientists. “We both had to know the answers to every question they could ask us,” Losada says.
They packed up the GEMs and set out for a two-week stay at the INFN facility in Frascati, just south of Rome. Other team members included two PhD students from the University of Glasgow, who would rely on Colvin and Losada’s data for their dissertations. A Chilean student was also there, who along with around 20 scientists from INFN and JLab rounded out the project team.
Particle accelerators are a rare commodity, and the two faced delays as other researchers made demands on the INFN resources. After lengthy struggles with the equipment, and the language barrier, Colvin and Losada were able to get their experiment up and running successfully their final four days in Frascati. They captured a large amount of data, which they will analyze in the coming semesters as part of their senior projects.
The two were able to get a little down time in during their stay, taking in the Spain-Italy Euro 2012 championship soccer match and keeping abreast of the happenings at the European Organization for Nuclear Research (CERN) in Geneva. Researchers there found conclusive evidence of the existence of the Higgs boson, a particle thought by many scientists to be a fundamental building block of the universe, while Colvin and Losada were just a few hundred miles away in Frascati. CERN was also the source of the materials for the GEM detectors Colvin assembled at JLab.
“Our trip to Italy was a huge opportunity for us, not only for resume building, but just to get that experience,” says Colvin. “Without the connections CNU has there’s no way that would have happened. It’s so rare to send undergraduates on an international experiment.”
Both plan to pursue graduate studies and careers in academia and research. -- Brian McGuire