AT/ECR CRYOGENICS Organisation, Procedures and Communication with TCR Presentation for TCR-ECR-ACR Meeting 2003 by K. Barth

Presentation Outline Cryogenics in General Cryogenics at CERN AT/ECR Cryogenics Organisation, inventory & geographic location Alarming procedures and contacts Summary

Cryogenics in general Low temperatures (120 K <) Provide cooling of superconducting magnets and cavities at temperatures down to 1.8 K Refrigerators at low temperatures inefficient Magnets have big “cold mass” and can quench External heat load  CRYOGENICS IS A SPECIAL UTILITY, WHICH TAKES LONG TO RECOVER! (1 hour stop needs 5 hours recovery)

Helium Cryogenics He 4 (atomic mass 4) exists in air (concentration 5.3 x ) He 4 is at room temperature ideal gas He 4 is not solidifying Very weak formation enthalpy Density of LHe: 125 g/liter 1 kg He = 8 liters LHe = 6 m 3 GHe cost approximately 30.- CHF He 4 gets 2.17K, 50 kPa Main properties of superfluid: Volumetric mass: 145 g/liter Capacity to transfer heat is very high Viscosity is very low

Cryogenics at CERN Cooling of superconducting magnets of the LHC accelerator Cooling of superconducting cavities of the LHC accelerator Cooling of the superconducting magnets and calorimeters installed in particle detectors for LHC and other experiments Cooling of test benches for LHC magnets and superconducting cables

Organisation (ECR / ACR cryogenics) ECR  cryogenics for experiments and (some) LHC test facilities ACR  cryogenics for accelerators and SM18/PM18 LHC test facilities Operation and Maintenance of all ACR & ECR cryogenic installation is done via an industrial contract (C169) by the consortium AIR LIQUIDE/ LINDE / SERCO (ALLS)

AT - ECR Organisation

North Area Fixed Target Experiments: COMPASS, NA49 (2), ATLAS/H8, CMS/RD5 NA LHC magnet test facility block4 CERN Axion Solar Telescope PA8 LHC Cable Test Facility Meyrin bldg. 163 Cryolab Central Liquefier Meyrin, bldg. 165 ATLAS Magnet Test Facility Meyrin, West Area Hall 180 BT magnet test bench (1.2 kW plant) Solenoid test bench (BOC plant) COLDEX, SPS BA4 AT/ECR 12 Cryoplants in operation (2003)

Alarming (TCR Procedure) Standby duty (piquet) operator for each cryo zone / control room Surveillance of the general alarm transmitted automatically from the ABB monitoring and supervisory system of the zone to the automatic alarm notification system (ANS) and in parallel to the alarm monitoring system of the technical control room (TCR) In case of a an alarm without a feedback of the responsible on-call operator (within 15 minutes), TCR operators try to reach cryogenics responsibles, respecting the following priority order: 1.) Call ALLS on-call operator of the zone (GSM & private number), if not reachable 2.) call ALLS on-call engineer (160683), if not reachable 3.) call CERN responsible technician of the zone, if not reachable 4.) call CERN responsible engineer K. Barth (163204, private tel. +33 (04) )

Alarming (ANS configuration 1) North Area zone (Prevessin Site) COMPASS, NA48 (LN2), NA49 (2), ATLAS/H8, CMS/RD5, LHC/Block 4 Crtl. Room: 76821, On-Call: , CERN Resp.: L. Stewart (160720) ALARME CRYOGENIE ZONE NORD LEP 1 Fault family: CRYO_GENERAL_PRE Fault member: CRYO-6 Fault code: 20 Fault description: DEFAUT GENERAL CERN Axion Solar Telescope (CAST) – LHC Point 8 CRYO REFRIG LHC CAST_COLDBOX /SR8 2875R DEFAUT GENERAL Crtl. Room: 76821, On-Call: , CERN Resp.: L. Stewart (160720) Fault family: CRYO_REFRIG_LHC Fault member: CAST_COLDBOX Fault code: 20 Fault description: DEFAUT GENERAL

Alarming (ANS configuration 2) Cryolab zone: 163, 165, 253, 243 (Meyrin Site) LHC Cable Test Facility (bldg. 163), Central Liquefier (bldg. 165), Helium Gas Management & Recovery (bldg. 243 & 253) Crtl. Room: 78802, On-Call: , CERN Resp.: R. Consentino (160713) ALARME CRYOGENIE BAT 163, 165, 253 Fault family: SERV_DIVERS_MEY Fault member: RDP-X25 Fault code: 1640 Fault description: COMMANDE BEEP BOITE FROIDE ATLAS WA zone: Hall 180 (Meyrin Site) ATLAS BT magnet test bench, Solenoid test bench Crtl. Room: 72365, On-Call: , CERN Resp.: S. Junker (164184)

Summary ECR cryogenics operation relies on good & fast communications with TCR in case of alarms While ANS is not working, calls from TCR is the only way to know about alarms, occurring outside normal working hours When ANS is working, calls from TCR will assure that cryo alarms have been noticed TCR is the communication interface to/from the users for information concerning cryogenics TCR is the co-ordination interface to the other external utilities (electricity, cooling and ventilation) required by cryogenics