Update of a Cooldown and Warmup Study for the Large Hadron Collider

The paper presents the inventory of components and materials for LHC magnets, especially for main dipoles and quadrupoles. A mathematical model for LHC transient modes, such as cooldown and warmup of a magnet, a standard cell and the eight LHC sectors, has been developed on the basis of the up-to-date layout of the LHC machine, and validated by experimental data. The model considers the momentum and continuity equations, as well as the energy equations for helium and materials. Based on the simulation results, the heat transfer in the magnets has been studied and the transient modes optimized.