Status of the activities on vacuum system

C. Garion

TBMWG, 20/06/2012

Outline

Vacuum study: Accelerating structure Main beam quadrupole

Interconnection: Deformable RF finger

Tribology tests under vacuum

Conclusion

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

Vacuum study – Accelerating structurePhase 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)

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

Vacuum study – Main beam quadrupole

Test set-up Pump down curve

Pressure down to 10-10 mbar

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 module Drive beam interconnection concept

Development ongoing Prototype with 2 convolutions

Tribology tests

Tests ongoing at Tekniker.

First screening tests have been done on steel substrate. Tests with titanium will be done soon.

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.