Physicists at CERN have sent a ping-pong ball around the Large Hadron Collider in order to test for defects. However, this is no ordinary ping-pong ball, it is ultra-clean, smaller than regulation size and fitted with a radio transmitter. This so called radio-frequency ball was used to test that the connections between the magnets are free from any defects.
The LHC’s 17-mile circumference is composed of eight straight sections joined together by eight arcs. More than 1600 magnets bend and focus the beams of particles that circle the collider at close to the speed of light. Interconnections, some of which resemble long, copper fingers, ensure that electricity flows from one magnet to the next.
These interconnections are installed at room temperature, but they must operate at well below freezing when the machine is turned on. The metal contracts by about 40 millimeters when this happens. Usually, the fingers manage to stay flat. But, occasionally, the fingers buckle, creating a bulge that can block a particle beam.
“The beam pipes are fragile,” says Vincent Baglin, the leader of the LHC beam vacuum section at CERN. “We always have to check and crosscheck to minimize any problems. This is a simple test that can prevent complicated issues.
The LHC has so far passed it’s tests and is on course for its scheduled restart in 2015