The CHORUS experiment to search for muon-neutrino --> tau-neutrino oscillation

A new experimental apparatus, designed principally for a high sensitivity search for ν μ → ν τ oscillation, has been successlly constructed and made operational by the CHORUS Collaboration for the CERN-WA95 experiment. It consists of a large emulsion target, a scintillating fiber tracker system with optoelectronics read-out, an air-core magnet, a set of trigger hodoscopes, a calorimeter based on the lead/scintillating-fiber technique, and a muon spectrometer. The design, construction and performance of the entire apparatus and of the different detectors are described.