The Si3, which is about 21 inches long, was shipped early this month to Cornell University , where it will be connected to other detectors in the CLEO III experiment, an international collaboration of about 20 universities. Once considered strictly theoretical, antimatter has been steadily emerging into the world of reality. Particles of antimatter look and behave the same as ordinary subatomic particles. But although they have the same mass as their matter counterparts, they have the opposite electrical charge. If particles and antiparticles meet, they instantly annihilate each other, releasing a large amount of energy in the process.
Physicists use particle accelerators to produce antiparticles.
At Cornell's Wilson Synchrotron Laboratory, electrons and their antimatter counterparts, positrons, are smashed together in an underground particle accelerator. As they collide, the particles annihilate, producing constituent particles whose properties must be precisely measured to further understand the nature of matter. Various detectors are located at specific distances and positions from the point of collision. As the newly created particles speed away, they penetrate the silicon in the Si3 detector, which sends signals to a computer detailing the precise positions of the particles. The combined signals from all the detectors in CLEO III will be used to measure data such as momentum, velocity, energy and penetrating power of particles produced in collisions.