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Due to the restricted space for the heaters and insulation in the normal conducting magnets of the HERA proton ring, the bakeout process must be done very carefully in order to prevent damage of the magnets. A special high temperature thermal insulating material allows bakeout of the stainless steel vacuum chambers by a heating jacket as thin as 3.5 mm. When built into a normal conducting accelerator magnet, a bakeout temperature of 300°C is achieved without overheating the surrounding magnet. After more than 24 h the maximum temperature of 68°C reached at the sensitive coil of the magnet is well below the 80°C critical temperature of the epoxy. With the described bakeout system no heat sink is necessary to protect the magnet's components from the high temperatures. Control and regulation of the temperature of the vacuum chambers are done by means of thermocouple probes, attached to the outer surface of the chambers near the coaxial heating elements.

The 1 km long ‘warm’ parts of the HERA proton ring vacuum system are currently being constructed. The layout and characteristics of the 10 −10 mbar system are described. Pump speed measurements for the UHV pumping stations are shown.