A calorimeter is a device that helps scientists measure the energy of a particle. This triangular section is layered with sheets of lead and plastic. The lead is heavy and dense, so the particles have a hard time going through it.
Scientists can tell how much energy a particle had by seeing how much lead it took to stop it.
The plastic gives off a flash of light when a particle goes through it. The scientists can tell how much lead it took to stop the particle by counting how many layers of plastic flashed. A complete section weighs several tons and will be installed in Hall B behind a set of drift chambers . This page is maintained by Steve Gagnon .