THERMOHYDRAULICS OF QUENCHES AND HELIUM RECOVERY IN THE LHC PROTOTYPEMAGNET STRINGS

In preparation for the Large Hadron Collider project, a 42.5 m-long pr ototype superconducting magnet string, representing a half-cell of the machine lattice, has been built and operated. A series of tests was p erformed to assess the thermohydraulics of resistive transitions (quen ches) of the superconducting magnets. These measurements provide the n ecessary foundation for describing the observed evolution of the heliu m in the cold mass and formulating a mathematical model based on energ y conservation. The evolution of helium after a quench simulated with the model reproduces the observations. We then extend the simulations to a full LHC cell, and finally analyse the recovery of helium dischar ged from the cold mass. (C) 1998 Elsevier Science Ltd. All rights rese rved.