Integrated thermal analysis of the production dipole magnets for the superconducting super collider

A thermal model of a 16.6-m-long Superconducting Super Collider dipole cryostat was developed to evaluate the system thermal behavior of the dipoles. The model incorporates in detail all the heat flow paths in the cryostat with the capacity to model all steady-state and transient thermal boundary conditions to which the cryostat is subjected during normal and upset conditions. The model predicts heat leaks to the cryogenics of 25.4 W per dipole to 80 K, 2.64 W per dipole to 20 K, and 0.174 W per dipole to 4.35 K during normal operation, which compare favorably to the established heat leak budgets. The model shows that the synchrotron radiation does not raise the temperature of the winding more than 0.2 K relative to the inlet temperature of the helium. Cooldown from room temperature to 55 K is shown to take from 1.5 to 3 h with flow rates of the order of 100-200 g/s. Warmup to room temperature from steady-state operating conditions takes approximately 17.5 h using 5-kW heaters. Recooling of the winding following a quench takes about 3.5 min from 70 K and 9 min from 300 K