Dark matter detector. Technician Carlo Bucci with apparatus to detect dark matter. Dark matter is as yet undetected matter postulated to exist in the universe. Neutrinos, elementary particles produced by nuclear reactions in stars and in supernova explosions, are possible candidates. This is a cryostat, the copper inner structure of the detector tower. It will be surrounded by crystals of tellurium dioxide and encased in Roman lead, then housed in a vacuum in a refrigerator. Photographed at the Gran Sasso Laboratories, Abruzzo, Italy. The laboratories are located 1400 metres underground and are accessed from a 10 kilometre long road tunnel.