Can we optimise the clean up process further ?

V. Baglin CERN TE-VSC, Geneva

Vincent Baglin LHC Performance Workshop - Chamonix 2010 - 25-29 January 1

Back to sector 3-4

Vincent Baglin LHC Performance Workshop - Chamonix 2010 - 25-29 January 2

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

Ok MLI Soot Total

V1

54 124 35 213

V2

39 129 45 213

V1

26 % 58 % 16 % 100 %

V2

18 % 61 % 21 % 100 %

Total

22 % 59 % 19 % 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 m 2 1.2 g

i.e

0.1 m 2 ~ 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 mm 2 ) 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 1 st 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.

2 nd 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.

3 rd 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.

4 th 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)

• Weekly release of cleaned sector

Follow up

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

Thank you for your attention !!!

Vincent Baglin LHC Performance Workshop - Chamonix 2010 - 25-29 January 23