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Monday, January 13, 2014

Special Delivery

Construction Wraps Up on CMU Particle Detector Project

DetectorIt was almost like sending a child off to college - after 17 years of work, the last four in Wean Hall, Curtis Meyer watched as the particle detector that he and his colleagues had constructed was packed up, loaded into a moving van and sent off to the Jefferson Lab National Accelerator Facility in Newport News, Va.

The detector will be installed as part of the Department of Energy-funded GlueX experiment. GlueX aims to find a new type of subatomic particle called a hybrid meson, which researchers believe will allow for a better understanding of gluons, elementary particles that hold everyday matter together.

"We started thinking about this project in 1997. Finally moving all the pieces to the accelerator facility means it's all coming together," Meyer said. "But we still need to wait a few more years until we can actually do physics."

Meyer isn't the only one who has been working on the project at Carnegie Mellon. Over the years four doctoral students have worked on projects related to the GlueX experiment, and Meyer estimates another 40 to 50 undergraduate students have contributed to the project.

Moving the approximately 400 pound detector chamber last fall was no easy feat. The detector couldn't withstand any big shocks, and needed to be kept at a fairly constant temperature. The research group secured a truck that was open in the back, allowing them to easily control the temperature. The detector itself was placed on a specialized cart equipped with shock absorbers - students had earlier tested a prototype cart, wheeling it around the uneven sidewalks of campus.

Orchestrating the move was technician Gary Wilkin. Years ago, Wilkin had helped move another detector to Jefferson Lab (JLab), making him the resident expert on transporting large-scale physics equipment. When it was time for the detector to go, the group removed some of its electronics and wrapped the detector in bubble wrap. The cart was then wheeled to the Wean Hall loading dock, loaded onto the waiting truck and secured to the corners of the bed.

Since the JLab facility where the detector was headed wouldn't be open at night, the truck and detector spent an evening outside of Wilkin's house. The next morning Wilkin and former technician Amy Woodhall set off for Virginia. They followed a carefully mapped out eight-hour route to Newport News, specifically avoiding the notoriously busy highways around Washington, D.C. Post-doctoral researcher Naomi Jarvis and graduate student Will Levine had made a test drive of the route in the weeks before the move to troubleshoot any possible road closures or obstacles that might be in the way.

The drive went smoothly, and the detector was unloaded into the accelerator facility the following morning. The detector will be installed early this year, and the accelerator will send its first beam of photons by the end of 2014, engineering runs should be completed by 2015, and researchers will start conducting experiments with the accelerator in 2016. It's then that Meyer and his collaborators hope to create hybrid mesons.

The work is important because it gets to the essence of everything, Meyer said.

"The matter that makes up everything we see around is primarily made of quarks tightly locked up inside nuclear matter by the gluons that mediate the extremely strong forces between the quarks," he said. The force is so strong that quarks can never be removed and studied in isolation.

"With the GlueX experiment at Jefferson Lab, we have the opportunity to do the next best thing," Meyer said. The GlueX experiment will excite the gluons between the quarks so researchers can study what this does to subatomic particles that can be observed.

"This will open a new window on the strongest force in nature," he said.

Technician Gary Wilkin guides the particle detector onto a truck. The detector was taken to Jefferson Lab last fall.

By: Jocelyn Duffy, jhdufy@andrew.cmu.edu