Yellow Pipes

The place to discuss the LHC. Commissioning, operation, issues, events ....
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Yellow Pipes

Post by Celladoor » Thu Apr 05, 2012 12:18 pm

Posts: 49
Joined: Thu Nov 18, 2010 3:07 pm

Re: Yellow Pipes

Post by adam_jeff » Thu Apr 05, 2012 1:02 pm

They're beam loss monitors (tip: there's a label just behind them!).
Specifically, they are ionisation chambers. They work on the same principle as a Geiger counter: a tube of gas is subject to a high voltage (thus the warning signs). When any particles from the beam hit the beam pipe, they create a shower of other particles, which in turn pass through the ionisation chamber, knocking off some electrons from some of the gas atoms inside. The electrons and ions are then pulled apart by the high voltage, creating a current which is measured, and which ends up as a little green or blue line on the LHC dashboard.

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