1. H. Herzog, 22th-26th September 2008 Cryogenics Operations 2008, CERN, Geneva, Switzerland 1 CRYOGENICS OPERATIONS 2008 Organized by CERN LARGE SCALE CRYOGENIC SYSTEM Hermann Herzog

2. H. Herzog, 22th-26th September 2008 Cryogenics Operations 2008, CERN, Geneva, Switzerland 2 Large scale cryogenic system The DESY Lab; Intro The HERA Cryogenic System Operational History Availability, Reliability Operational Experience Failures Summary

3. H. Herzog, 22th-26th September 2008 Cryogenics Operations 2008, CERN, Geneva, Switzerland 3 The Research Centre DESY Aerial view of the Lab

4. H. Herzog, 22th-26th September 2008Cryogenics Operations 2008, CERN, Geneva, Switzerland 4 The Research Centre DESY Aerial view of the Lab

5. H. Herzog, 22th-26th September 2008Cryogenics Operations 2008, CERN, Geneva, Switzerland 5 The Research Centre DESY Budget Finance Permanent Staff Education International Cooperation Permanent guest research groups Users of the DESY facilities

6. H. Herzog, 22th-26th September 2008Cryogenics Operations 2008, CERN, Geneva, Switzerland 6 The Research Centre DESY Long tradition on cryogenics @ DESYLong tradition on cryogenics @ DESY 1964 H 2 Liquefier 45l/h, bubble chamber 1970 He Liquefier, 12W 1972 He Liquefier, 200W, PLUTO 1979 He Liquefier, 200W, CELLO 1982 He Liquefier, 900W, cryostat devlp. 1985 He Liquefier, 300W, s.c. cavity HERA 1985 3x large He Liquefier, HERA

7. H. Herzog, 22th-26th September 2008Cryogenics Operations 2008, CERN, Geneva, Switzerland 7 Long tradition on cryogenics @ DESY 1964 -1972 H2 Liquefier 45l/h for Bubble Chamber

8. H. Herzog, 22th-26th September 2008Cryogenics Operations 2008, CERN, Geneva, Switzerland 8 Long tradition on cryogenics @ DESY 1982 He Liquefier 900W HERA Cryostat development, s.c. cavities

9. H. Herzog, 22th-26th September 2008Cryogenics Operations 2008, CERN, Geneva, Switzerland 9 Long tradition on cryogenics @ DESY 1985 He Liquefier 300W s.c. cavity test facility

10. H. Herzog, 22th-26th September 2008Cryogenics Operations 2008, CERN, Geneva, Switzerland 10 Long tradition on cryogenics @ DESY 1985 3 large He-Refrigerators for HERA

11. H. Herzog, 22th-26th September 2008Cryogenics Operations 2008, CERN, Geneva, Switzerland 11 Overview Current (HERA-) Cryoplant

12. H. Herzog, 22th-26th September 2008Cryogenics Operations 2008, CERN, Geneva, Switzerland 12 Operational history of the HERA cryoplant EVENTTIME HERA approvedMay 1984 Construction of the cryogenic plant1985 + 1986 Commissioning of the first cold box1987 Cryogenic supply of the magnet test facility1987 – 1990 Installation of the helium distribution system in the ring tunnel1988 – 1989 Installation of the 646 s.c. proton ring magnets in the tunnel1989 – 1990 First cool down of a HERA octantMay 1990 Cool down of all HERA magnet octantsEnd of 1990 First stored proton beamApril 1991 Installation of 16 s.c. cavities in the electron ring1991 – 1992 Experiments H1 and ZEUS enter the beam lineDec./Jan. 1991/1992 Nominal proton energy (820 GeV) reachedMarch 1992 Luminosity to the experiments, start of the experim. Programme Cryo systems steady state cond. @4.4K (1030 mbar) June 1992 1 st test of one cryo system @4K for 24 hsNov. 1993 Installation of additional transfer line and feed box for experiment HERMES1995 2 nd run of complete cryo system @4K for 2 monthsOct. + Nov. 1997 Proton ring upgrade to 920GeV, cryo systems operates now @4K (650 mbar) July 1998 Installation of FEL-distribution, cryogenics supply to the VUV-FEL (TESLA-Test Facility)1998 Installation of 4 s.c. magnets in the interaction – area (lumi-upgrade)2000 Installation of 2 frequency controlled motor drives (upgrade to two JT compressors)March 2003 Installation of 5 frequency controlled motor drives (upgrade to five JT compressors)Nov. 2005 End of HERA-run, cryo systems operating stoppedJuly/31/ 2007

13. H. Herzog, 22th-26th September 2008Cryogenics Operations 2008, CERN, Geneva, Switzerland 13 Basic Agreement DESY-LINDE Operation and maintenance of the Cryoplant under full responsibility of LINDE KRYOTECHNIK AG all operational funds7 high skilled professionals part of the manpowerall spare parts

14. H. Herzog, 22th-26th September 2008Cryogenics Operations 2008, CERN, Geneva, Switzerland 14 Operational experience Shift system 6 shift crews 24/7/12 at least 1 operator on shift

15. H. Herzog, 22th-26th September 2008Cryogenics Operations 2008, CERN, Geneva, Switzerland 15 Operational experience ItemFailure reasonFailure rate Screw Compressorsfail to operate shaft seal excess leak capacity control fail to operate Motorsball bearing damaged Oil pumpsshaft seal excess leak oil leak > 5 l / 1000 hs Control valves (air operated)fail to operate leak past the seat Motor driven fan (oil cooler)ball bearing damaged v-belt broken Liquid He level sensorerratic indication Electrical switches, contacts, transformer, power supplies thermal current switches fail circuit breaker fails to operate Process control computer system system fail to operate crates fail to operate Instrumentation, pressure transmitter, flow meter, erratic output capillary plugging Cold cathode vacuum gaugeerratic indication

16. H. Herzog, 22th-26th September 2008Cryogenics Operations 2008, CERN, Geneva, Switzerland 16 Operational experience ItemIntervalDescription Compressors Coupling adjustment general overhaul every 25.000 hs every year Inspection of bearings Exchange of all sealing's Functional test check alignment Motorsgeneral overhaul every 25.000 hs Inspection of bearings Insulation bath of the motor windings Oil pumpsoil leak > 5 l / 1000 hsExchange shaft seal Valvesevery 2 yearsLeak test, gauge Adsorbersevery 2 yearsLeak test Purifiersevery 2 yearsLeak test, Electrical switches, contacts, transformer, power supplies every 2 yearsGeneral cleaning, inspection, test and gauge Process control systemevery 2 years continuously Hardware exchanges, Software upgrades, Program updates Instrumentation, pressure transmitter, flow meter, pressure and temperature switches every 2 yearsTest and gauge, pump and purge plugged capillaries vacuum pumpsgeneral overhaul every 2 years exch. cold cathode vac. gauge

17. H. Herzog, 22th-26th September 2008Cryogenics Operations 2008, CERN, Geneva, Switzerland 17 Failure statistics But this is the failure statistics Including infrastructure of Helium users! Failure statistics of refrigerating plant only.

18. H. Herzog, 22th-26th September 2008Cryogenics Operations 2008, CERN, Geneva, Switzerland 18 Summary Throughout 17 years of HERA-operation the refrigeration plant compensated the cryogenic loads of the HERA accelerator, the HERA experiments and temporarily the FLASH accelerator and other recipients with a corresponding availability of 98,7 %. Related to the availability of the refrigeration plant itself this value exceeds 99 %. A plant-availability of 99 % is possible if periodical maintenance as well as the exchange of critical components (O-ring sealing, power supplies, emergency- power supplies, PLC’s, etc) is carried out.