The giant helium refrigeration plant at DESY, the German particle physics laboratory in Hamburg. The plant, the largest in Europe, provides the coolant for the superconducting magnets used in the HERA particle collider. HERA (Hadron-Electron Ring Accelerator) is a new type of accelerator which will collide 820 GeV protons (members of the hadron family of particles) with 30 GeV electrons. HERA is due to start operations in 1989-1990. The refrigeration plant compresses, purifies, & cools helium gas to -269 degrees C (4. 6K) before it is circulated through the HERA magnets. The plant is in a hall measuring 33x72 metres & consists of 3 units, 2 of which will be used normally. Photo taken Dec. 1987.