In The Beginning
SMU Physicists Participate In An International Experiment To Explore Origins Of The Universe
By Kathleen Tibbetts
The Waiting Game
At 10 p.m. on a Saturday night in April, a handful of SMU scientists continue working at the European Organization for Nuclear Research (CERN) in Geneva, Switzerland. A scattering of lights illuminates the windows in several buildings along the Rue Einstein, where researchers from dozens of countries and hundreds of institutions are combining their expertise on the Large Hadron Collider (LHC) – the biggest physics experiment in history.
Ryszard Stroynowski, chair and professor of physics at SMU, points out each building in succession to a group of visitors. “By October, every light in every one of these windows will be on all night,” he says. By then, the LHC is expected to be fully tested and ready to work. When the largest particle accelerator ever constructed becomes fully operational, it will hurl protons at one another with precision to a fraction of a micron and with velocities approaching the speed of light. These conditions will allow physicists to recreate and record conditions at the origin of the universe – and possibly discover the mechanisms that cause particles in space to acquire their differences in mass.
For Stroynowski, who has worked for almost 20 years to help make the experiment a reality, words seem inadequate to capture the anticipation surrounding its imminent activation. “It is somewhat like that of a 6-year-old kid on Christmas Eve, waiting for Santa Claus,” he says. “The time stretches almost unbearably long.” The LHC will be the site of several experiments in high-energy physics with high-profile collaborators such as Harvard and Duke and national laboratories including Argonne, Brookhaven, Lawrence Berkeley and Fermilab. None of the experiments is more imposing than ATLAS, one of two general-purpose particle detectors in the LHC array. At about 42 meters long and weighing 7,000 tons, ATLAS fills a 12-story cavern beneath the CERN facilities in Meyrin, Switzerland, just outside Geneva. It is a tight fit: ATLAS overwhelms even the vast space it occupies. A catwalk, not quite wide enough for two people to stand side by side, encircles the device and allows an occasional dizzying view into its works.
In ATLAS’ case, size matters: The detector’s scale will help to focus and release the maximum amount of energy from each subatomic collision. A series of bar codes on each of its parts ensure that the detector’s components, whether palm-sized or room-sized, are aligned and locked with the perfect precision required for operability. Scientists from 37 countries and regions and 167 institutions participated in its design and construction.
As U.S. coordinator for the literal and experimental heart of the ATLAS detector – its Liquid Argon Calorimeter – Stroynowski is helping to finalize the last details of the detector’s operation in anticipation of the extensive testing, scheduled to begin in August. He leads an SMU delegation that includes Robert Kehoe and Jingbo Ye, assistant professors of physics in Dedman College of Humanities and Sciences. SMU scientists are completing work on the computer software interfaces that will control the device, which measures energy deposited by the flying debris of smashed atoms. A cadre of University graduate students and postdoctoral fellows also is working on data processing for ATLAS’ 220,000 channels of electronic signals – an information stream larger than the Internet traffic of a small country.
An estimated 53,000 visitors crowded the CERN facilities on the organization’s “Day of Open Doors” April 6, eager for a glimpse of the work that CNN International has named one of the “Seven Wonders of the Modern World.” At the beginning of May, the areas were sealed off in preparation for the first round of testing. Computers will remotely control the ATLAS experiment, which will not be touched by human hands because of the radiation released by the atomic collisions. Safety is the reason for the elaborate lockdown procedure involving more than 80 keys, each coded to a different individual’s biometric data. The system is designed to lock out any use of the device if even one key is unaccounted for. “ATLAS has been built to run for at least 15 years with no direct human intervention,” Stroynowski says. “It will be as if we have shot it into space.” Currently, the initial test run is schedule to begin September 1, 2008.