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Can we optimise the clean up process further ?

V. BaglinCERN TE-VSC, Geneva

Vincent Baglin LHC Performance Workshop - Chamonix 2010 - 25-29 January

Vincent Baglin LHC Performance Workshop - Chamonix 2010 - 25-29 January2

Back to sector 3-4

Inspections• 4.8 km of beam lines have been inspected by endoscope and documented• 212 interconnections have been inspected and documented

Results of inspections• Soot, MLI, metallic debris

LSS3 LSS4

V1 V2 V1 V2 Total

Ok 54 39 26 % 18 % 22 %

MLI 124 129 58 % 61 % 59 %

Soot 35 45 16 % 21 % 19 %

Total 213 213 100 % 100 % 100 %

Development of tooling• In parallel to the inspections task, tools were developped to clean the sector• A vacuum cleaner was developped by the vacuum group !

Version 1

Development of tooling• Upgraded version with attached endoscope

Version 2

Development of tooling• Harvest trials were done in the tunnel by end November 2008• Automatic pumping/venting based on RF ball technology

• Q8R4 till Q13R4 line V1 (~ 230 m)

3.2 g i.e 0.4 m2 1.2 g i.e 0.1 m2 ~ 100 bits

Development of tooling• Chimney sweeping stick for beam screens polluted with soot• First successful tests before Xmas 2008

Draft of cleaning procedure

• By mid December 2008

• A two step method :

- removal of gross contamination - fine cleaning

Validation of the vacuum cleaner• By January 2009• In the lab, use of a mock-up and real plug in modules extracted from sector 3-4

Results after 2 passages in a PIM (8 min total)

Evaluation in the tunnel• Parameters to define :

- number of passages- time per PIM- time per beam screen- nozzle opening

Chamonix 2009

Definition of the required performance

• After discussion with AB-ABP and following Chamonix it was agreed with the management that :

- 1 fibre per half-cell (there are 82 half-cells to clean) - 2 debris (MLI or other less than 1 mm2) per magnet (there are 304 beam tube magnets to clean)

• Can be left in the beam tube after the cleaning process !

Detailed cleaning procedure• Achieved by end-February

1st Step, automatic pumping/venting of the sector during at least one hour. At the end of this time, additional automatic pumping/venting of the so-called pumping hoses (vacuum ports at each quadrupole) during at least 15 minutes.

2nd step, 10 passages along the vacuum sector with the nozzle-endoscope tool and the automatic pumping/venting. During passage 1, 2 and 3, the nozzle-endoscope tool should be applied during 10 minutes at each PIM then 5 minutes are required. In the beam tube, the speed of the nozzle-endoscope tool is 3 to 4 m/minute. In case of an event visible by the endoscope camera, the operator shall insist with the tool to remove the event. The beam line is subjected to automatic pumping/venting during passages 1,2,3,4,9 and 10. Additional automatic pumping/venting of the pumping hose is installed in parallel during passages 5,6,7,8. After each passage, the debris are collected in a plastic bag for future documentation.

3rd step, endoscopic control. Once a sector has been cleaned, quality control is ensured by a systematic endoscopic inspection. Each beam position monitor, each PIM, each entrance, mid and end part of the beam screen and finally, each unexpected event are recorded by video. A report is issued at the end of the control.

4th step, validation of the cleaning of the sector and release of the sector for PIM welding. In the absence of any quantitative information from the expert, a maximum of one fibre per half-cell and two debris (from super insulation or other) per magnet is tolerated.

• Cleaning rate :~ 50 m / day / team

• Time for PIMs : 3h 15 min !

Follow up• Day by day reporting and analysis of the cleaning state

Follow up• Final endoscopy report (both directions)

Follow up• Weekly release of cleaned sector

Procedure set up phase

Follow up• Documentation of non-conformities

Examples of NC

Difficulties• CERN was not ready to such an incident :

At the beginning, communication inside CERN was extremely reduced

Need to built a team of experts on a new task Need to identify, built, buy and qualify tooling

Difficulties• On the field :

Issue with resources : experts were called for other (urgent) activities Keep the motivation of the team members Issue with coactivity (and performance) :

Why should we clean a beam tube while somebody else beside you is doing a hole in a cryostat for a relief valve ?

Issue with material : ageing or damaging when the nozzle is stuck in a PIM (required the cutting of it by TE-MSC)

Qualification of the cleaning process. How to distinguish with an endoscope a fibre or a MLI from a scratch or a stain ? Forget its estimation by vacuum performance ! Better stay quiet, away from planning’s stress and ask your team to clean a second time a sector in case of doubt : easy to say …

Conclusions

• A new methodology was developed and applied for the cleanup process of sector 3-4

• ~ 3 months were required to set up the process

• ~ 3 months were required to cleanup the sector

• Final inspection was done by an endoscope

• We have 6 sets of tooling ready to intervene

• I hope they will stay on the shelves forever !

Acknowledgments

• FSU, AL43 and TS-MME teams for performing an excellent and difficult work in the tunnel

• HNINP collaboration for the qualification endoscopies

• B. Henrist, A Vidal, G. Schneider, E. Page, J. Finelle, B. Jenninger, A. Sinturel, E. Mahner, H. Kos for their developements, commitment and work performed in the tunnel

• J.M Jimenez, P. Cruikshank, R. Veness for their supports and expertises

Vincent Baglin LHC Performance Workshop - Chamonix 2010 - 25-29 January23

Thank you for your attention !!!