The cryogenic operation of the superconducting magnet system in the HERA proton storage ring: cool down, steady state operation, quench recovery processes

The 6.4 km long superconducting proton storage ring of HERA was completed in 1990. In October the first halfring was cooled, in December the second one. Steady state operation could be established after about 200 hours. The authors report on the cryogenic operation of the system during cooldown and steady state operation and give values for thermal losses. One octant was excited up to values exceeding the design current. Some results of quench tests in this octant are presented. All performance tests have displayed satisfactory results. Reliability has been excellent over running times which vary, depending on the date of completion, from several months to 2.5 years. All control and safety devices work well. Heat loads and refrigeration power are as designed. From the cryogenic point of view the ring is ready for operation.<>