The distributed control system for the HERA cryogenic plant, and its first test

Abstract The 6.3 km superconducting proton storage-ring of the HERA project at DESY (Hamburg) will contain 422 dipole and 224 quadrupole magnets. Three refrigerators produce supercritical helium, which is fed into two transfer lines that supply the individual sections of the ring through 16 cryogenic boxes. Since there is no access to the cryogenic components in the tunnel while HERA is running, all cryogenic components need full remote control. The design of the cryogenic readout system in the HERA tunnel is based on the existing PADAC/SEDAC design used for accelerator control. Special requirements of this readout system will be described. In addition, there will be an overview of the diagnostic tools developed at DESY. From July to September 1989, the superconducting coils of the two experiments ZEUS and H1 were fed with liquid helium through the transfer line and controlled by the computer system. First results will be discussed.