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LHC Cryogenics Status and Perspectives

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Presentation on theme: "LHC Cryogenics Status and Perspectives"— Presentation transcript:

1 LHC Cryogenics Status and Perspectives
Serge Claudet, on behalf of the LHC Cryogenics group LHC - MAC Dec 2007

2 Content Introduction Main facts from sector 7-8 (January to July 2007)
Last projects towards completion Identified weak points and status Cryo HWC activities since Mid 2007 Action plans Summary S. Claudet Dec'07 LHC-MAC Cryogenics

3 S. Claudet Dec'07 LHC-MAC Cryogenics

4 LHC Sector 4-5 scheme 4.5 K 1.9 K 3.3 km 4’700 t @ 1.9K ≈ 10t/15tHe
S. Claudet Dec'07 LHC-MAC Cryogenics

5 Content Introduction Main facts from sector 7-8 (January to July 2007)
Last projects towards completion Identified weak points and status Cryo HWC activities since Mid 2007 Action plans Summary S. Claudet Dec'07 LHC-MAC Cryogenics

6 LHC sector 7-8 - First cool-down
S. Claudet Dec'07 LHC-MAC Cryogenics

7 Availability for HWC: From 7-8 to others
Cryo Maintain LSS: 85% (Since 1st May) Cryo Maintain ARC: 66% (Since 1st June) DFBMs DFBAs Availability for the powering phase for sector 7-8 and expected one for the coming sectors Target LSS: 90% (incl. time lost for quench recovery) Target ARC: 80% (incl. time lost for quench recovery) + Cryogenic tuning to be minimised ?!? S. Claudet Dec'07 LHC-MAC Cryogenics

8 Heat inleaks Average distributed heat inleak at 1.9 K: 0.2 W/m
20 % of cells operating with degraded insulation vacuum Average distributed heat inleak of cells with good vacuum: 0.14 W/m 33 % below the design estimation Average global thermal shield heat inleak: 6.6 W/m 15 % below the design estimation S. Claudet Dec'07 LHC-MAC Cryogenics

9 LHC Cryogenics: duration of cool-down phases
Design LHC 7-8 Final 9 d 21 d 3 d 14 d 1 d 80 K 20 K 4.5 K 1.9 K Total 14 d / 2 wks 70 d / 10 wks ELQA 4 d 7 d 28 d / 4 wks Excluding ELQA or extra-works : Sketches intended to illustrate achievements and medium term expectations S. Claudet - Jul’07 Proposed for schedule: 8wks-6wks-4wks S. Claudet Dec'07 LHC-MAC Cryogenics

10 Content Introduction Main facts from sector 7-8 (January to July 2007)
Last projects towards completion Identified weak points and status Cryo HWC activities since Mid 2007 Action plans Summary S. Claudet Dec'07 LHC-MAC Cryogenics

11 Superconducting links (DSL)
Few hundred meters link between DFBL’s and stand-alone magnets S. Claudet Dec'07 LHC-MAC Cryogenics

12 Many non conformities from contractor, repaired by CERN
Problems with leaks at the factory-made welds on belows Many non conformities from contractor, repaired by CERN => Impact on sector 3-4 S. Claudet Dec'07 LHC-MAC Cryogenics

13 Global pressure test of magnets and cryolines
Sector 7-8, 25 Nov 2006 Six sectors May’07 to Nov’07 Remaining 1 sector in Dec’07 S. Claudet Dec'07 LHC-MAC Cryogenics

14 Content Introduction Main facts from sector 7-8 (January to July 2007)
Last projects towards completion Identified weak points and status Cryo HWC activities since Mid 2007 Action plans Summary S. Claudet Dec'07 LHC-MAC Cryogenics

15 On-going actions & plans @ MAC21
LN2 logistics to be continued; turbine and flow controls to be improved for 20 K phase Heat loads to be further checked and analysed JT valves to be checked and replaced (8x27) LHe level / anti-condensation for DFB’s to be finalised Instrumentation & controls to be available & more reliable Test of specific tool QUI to separate installation/operation Helium inventory & strategy to be confirmed OK, Faster at sector 4-5, to be continued When conditions OK Done for 8 arcs, singularities being treated OK, to be continued OK, to be continued Done, no longer required Defined, to be implemented S. Claudet Dec'07 LHC-MAC Cryogenics

16 DFB Commissioning: levels and anti-condensation
LT836 LT837 LT864 LT865 LT866 LT867 ≈ 5 m S. Claudet Dec'07 LHC-MAC Cryogenics

17 Dry air protection of 600A chimneys of DFBAH
Consolidation of DFBs Protective box Liquid helium level gauges Installation of calibrated level gauges. Installation of a protective box around the level gauges Anti-condensation system 6 kA, 13 kA, 600 A dry air protection: current lead insulating flange + top of chimney flange, connected in series. Interim solution for sector 4-5 120A active heating system + dry air (depending on tests) Configuration of LG 6 kA, 13 kA (322) 600 A (178) 120 A (36) Dry air protection of 600A chimneys of DFBAH LHC-MAC Cryogenics S. Claudet Dec'07

18 Commissioning DFBs of sector 4-5
IR4R IR5L DFBMK: boil-off cross-check to be finalized DFBML: released for ELQA DFBMG: released for powering DFBAH LCM: liquid level confirmed abnormal behaviour of several control valves for 600A CL DFBAH HCM: liquid level confirmed - abnormal reading of temperature sensors of 13kA CL #1 DFBAI HCM: liquid level cross-checking in progress Liquid level control to be tuned. DFBAI LCM: liquid level confirmed abnormal behaviour of several control valves for 600A CL. Several valves had to be replaced by caps! DFBLD: boil-off performed - Liquid level control to be tuned. LHC-MAC Cryogenics S. Claudet Dec'07

19 S. Claudet Dec'07 LHC-MAC Cryogenics

20 Content Introduction Main facts from sector 7-8 (January to July 2007)
Last projects towards completion Identified weak points and status Cryo HWC activities since Mid 2007 Action plans Summary S. Claudet Dec'07 LHC-MAC Cryogenics

21 Flushing sectors before cool-down
Dust Debris Kapton Reports And possible shorts in diodes ! But the sooner the best !!! S. Claudet Dec'07 LHC-MAC Cryogenics

22 LHC - 1st cool-down sector 4-5
Cool-down stopped twice due to leaks during cool-down P5 P4 Two hoses in DFBA’s became leaky during cool-down 6 weeks stand-by: looks promising S. Claudet Dec'07 LHC-MAC Cryogenics

23 LHC Sector 4-5: 1st cool-down (2007)
Cool-down to 1.9K Cryogenic tuning 1st leak and repair Powering tests 2nd leak and repair S. Claudet Dec'07 LHC-MAC Cryogenics

24 LHC 45: Cryogenic tuning toward 1.9K
With contractor Cryogenic tuning at 1.9K Stops due to external sources Stops due to 1.8K units with small air leak in cold sub-atmospheric circuit Last 4 weeks (6Nov’07 to 5Dec’07) S. Claudet Dec'07 LHC-MAC Cryogenics

25 Cool-down of other sectors
7-8 & 4-5: 1st cool-down in 2007 5-6: 300K-80K Nov-Dec 2007 Short in diode and repair 7-8 & 8-1: start wk51 for Jan’08 5-6 & 6-7: Restart wk And four remaining sectors Feb’08 to Apr’08 S. Claudet Dec'07 LHC-MAC Cryogenics

26 Content Introduction Main facts from sector 7-8 (January to July 2007)
Last projects towards completion Identified weak points and status Cryo HWC activities since Mid 2007 Action plans Summary S. Claudet Dec'07 LHC-MAC Cryogenics

27 On-going actions & plans
Cool-down process & Heat loads to be further checked and analysed Refrigeration: Ex-LEP upgrade consolidations and 1.8K units Instrumentation & controls to be terminated and consolidated LHe level / anti-condensation for DFB’s to be deployed He guard along sectors to be consolidated Few other consolidations to be evaluated Operation procedures and teams know-how to be re-inforced Strategy for Helium inventory defined, to be implemented S. Claudet Dec'07 LHC-MAC Cryogenics

28 Summary The LHC cryogenic system is progressively being commissioned, with signs of “learning curve” Consolidation program started (JT valves, DFB’s, controls, helium) and to be continued 2007 has been a difficult year of commissioning, and most likely 2008 will be a difficult year towards the expected first beams and collisions Looking forward to “routine” operation !!! S. Claudet Dec'07 LHC-MAC Cryogenics


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