Physicists tackle new project

Members of the IU physics department are just now finishing the first stage of work on a massive, multi-national science endeavor known as ATLAS.\nATLAS is the name of a yet to be constructed, multi-purpose detector for particle physicists to observe the behavior of high energy proton collisions. When completed in 2007, the cylindrical ATLAS Detector will be five stories high and weigh 7,000 tons.\nAnd it will be just a small piece of a larger structure called the Large Hadron Collider. The Collider is a giant ring-shaped tunnel with a diameter over 8 kilometers that is located underground, beneath France and Switzerland. In the LHC, beams of protons will be sped up in opposite directions in order to collide with one another.\n"This is one of the most exciting projects in science," said John Callahan, project engineer. "The LHC, when completed, will give us a window into the very fabric of matter." \nThe ATLAS Detector is a combination of four major components, each designed to measure different factors of a proton collision. At the very center of the ATLAS Detector is the Inner Tracker component, a piece of which IU physicists had been building. It will measure things like momentum and direction of the collisions. \nThe Transition Radiation Tracker, IU's contribution to the ATLAS project, is comprised of large bundles of gas-filled straws threaded with hair-thin wires. Members of the IU team have had to design and build the TRT essentially by hand. \n"The TRT is a pretty intricate experiment with thousands of small parts that all have to fit together in quite a limited space," said Curt Baxter, who has been providing Computer Aided Drafting support for the project for the past four years.\nDebbie Hamm is one of the electronics technicians, whose duties include stringing, reworking and testing various TRT modules. \n"I have also built radiator assemblies, test boxes, stringing stations and a few other jobs that are essential for the build up of these modules," Hamm said.\nAccording to Project Manager Harold Ogren, many of the project team members will be following their creation to the CERN Laboratory in Switzerland. Besides faculty from the IU Physics Department, ATLAS involves about 2,000 physicists from 34 countries. The next several years will consist of numerous tests to ensure that nothing goes wrong when the experiment begins in 2007. \n"We get to work with wonderful people from all over the world. The people are very creative and great to work with," Callahan said, adding that he is excited to be a part of something this big. \nThe LHC is unique because it will be able to accelerate proton beams to high levels of energy (7 TeV or 7 million electron volts). The ATLAS Detector will be installed in a position along the track of the LHC. It will contain various types of measurement devices to observe and chart the behavior of the colliding electrons. \nAnother useful feature of the LHC is how many proton collisions it will be able to produce. Due to the minute size of protons, there are usually very small odds against two colliding with each other. To ensure that collisions occur frequently, huge amounts of protons must be collided with one another. \nBut collisions do not always act the same way. The types of collisions interesting to physicists are very rare. By increasing the rate of collisions, the rare types can be observed more frequently. \n"It is a safe bet that this project will extend our understanding in many areas that have long been pursued, and it is also a safe bet that things will be revealed that we do not currently dream of," Callahan said. "That's what basic research is all about."\nFor more info on ATLAS, please visit pdg.lbl.gov/atlas.