1. Status of the activities on vacuum system C. Garion TBMWG, 20/06/2012

2. Outline Vacuum study:  Accelerating structure  Main beam quadrupole Interconnection:  Deformable RF finger Tribology tests under vacuum Conclusion

3. Vacuum study – Accelerating structure Measurement on the additional manifold is representative of average pressure along the beam axis but higher than real configuration (factor ~2) Aim: Influence of adjacent ion pump on the vacuum of an accelerating structure pumped with the capacitorr. Phase 1: Qualification of test configuration

4. Vacuum study – Accelerating structure Phase 2: test of the Accelerating Structure with a NEG cartridge and an ion pump with reduced pumping speed.  Capacitorr on the vacuum manifold  Diaphragm + Nextorr at the extremity, IP on, NEG not activated Diaphragm (pumping speed ~ 1.5l/s)

5. Vacuum study – Accelerating structure Pump down curve (bakeout of Te and ion pump not represented).  Pressure in the accelerating structure with a NEG cartridge and small pumping speed ion pump below 10 -9 mbar.  For the baseline:  keep the space reservation for the Nextorr pumps everywhere,  Optimize the number of Nextorr pumps: ½ Capacitorr NEG cartridge pump, ½ Nextorr pump 5.9.10 -10 mbar

6. Vacuum study – Main beam quadrupole Test set-up Pump down curve  Pressure down to 10 -10 mbar

7. Interconnection – Deformable RF finger Deformable thin walled sheet: with both extremities attached to the adjacent chamber sort of corrugated bellows in free position almost straight in operation position Presented by A. Lacroix (23/03/2012) Two beam moduleDrive beam interconnection concept Development ongoing Prototype with 2 convolutions

8. Tribology tests Tests ongoing at Tekniker. First screening tests have been done on steel substrate. Tests with titanium will be done soon.

9. Conclusion The technical solution with small ion and NEG pumps (Nextorr) is adapted to the CLIC module and exhibits good vacuum performance. Vacuum tests have been done on the MB quad vacuum chamber and the results fulfill the specifications. Development of deformable RF fingers and tribology tests are ongoing.