Cryogenic and magnetic tests of the twin aperture prototype dipole in the Saclay test facility

The authors describe the test facility and the cryogenic and magnetic measurements performed on the twin aperture prototype (TAP) dipole for the CERN Large Hadron Collider (LHC). The magnet, designed by CERN and built by European industries, was tested in a facility built at CE Saclay. The focus is on the cryogenic system, which enables prototype magnets to be tested in superfluid helium; on the data acquisition systems, including a system for magnetic measurements; and on the results which were obtained during the tests.