This is a mechanical model of one of the 32 photomultiplier tubes that are strung along the interior walls of the MicroBooNE detector. When a neutrino collides with an argon nucleus in the MicroBooNE detector, the resulting charged particles excite the argon to produce photons. The photons will travel to a photomultiplier tube such as the one pictured. As the name suggests, a photomultiplier amplifies the light signal, and the signal is then read out by a computer. The data from the photons give information about the location and energy of the original neutrino interaction. Photo: Reidar Hahn