Status of the activities on the vacuum system C. Garion TBMWG, 27/03/2013 Outline: ON/OFF mechanism: tribology study Pumping technology: MB quad VC Accelerating structure Deformable RF fingers

ON/OFF mechanism, tribology study Presentation and performance: Configuration and forces: Out stroke In stroke A B FA ~ 2 N, FB ~ 1 N FA ~ 1.6 N, FB ~ 0.6 N Maximum stroke: 7.7 mm Pull time : s Push time: 20 s Lifetime: 10 5 cycles in 10 years ON-OFF MECHANISM Tribology study carried out at Tekniker, Spain

ON/OFF mechanism, tribology study Specification for the tribo-pair: Compatibility of the materials with UHV  Polymer, organic components forbidden A-magnetic material “light material” for the moving part  Titanium rod Tribological properties depend on : Material Mechanical stresses (force, contact surface) Physical Chemical Kinematic Questions addressed: Which coating with low friction coefficient and high wear resistance? Which substrate? Hard or soft?

ON/OFF mechanism, tribology study Test set-up: Pin on flat configuration Test conditions  Applied load: 2N  Sliding velocity: 5 mm/s  Oscillation amplitude: 5 mm  Test temperature: 25°C  Environment: High Vacuum (1x10-8 mbar)  Cycles: 100/500/2000/10000  A ball of 3 mm of diameter of Si3N4 was selected as counter material.  Conservative stress state

ON/OFF mechanism, tribology study Test results:  Coating selection: Flat sampleSubstrateSubstrate surface treatment CoatingDeposition method 1TiFeNone- 2TiFeMirror polished- 3AISI 440CMirror polished- 4AISI 440CMirror polishedTaOHiPIMS 5AISI 440CMirror polishedTaNHiPIMS 6AISI 440CMirror polishedTaNHiPIMS 7AISI 440CMirror polishedTaNDC 8AISI 440CMirror polishedTaNHiPIMS, multilayer 9AISI 440CMirror polishedTaNHiPIMS  TaN multilayer has low friction coefficient Friction coefficient 200 cycles

ON/OFF mechanism, tribology study Test results:  Coating selection: wear resistance  TaN multilayer has good wear resistance

ON/OFF mechanism, tribology study Test results:  behavior of TaN multilayer coating  Slight increase of the friction coefficient during the first 3000 cycles and then constant at around 0.1,  Light wear track on outer layer  Good tribological performance Evolution of friction coefficient up to cycles Wear track after cycles

ON/OFF mechanism, tribology study Test results:  coating substrate selection:  Titanium is not suitable for the hard TaN coating o Titanium (rod) o 304L 1 1  304L is not suitable for the hard TaN coating

ON/OFF mechanism, tribology study Main conclusions: Multilayer TaN coating exhibits low friction coefficient and good wear resistance Coating is not appropriate neither on the titanium (rod) nor 304L (bush) Coating has to be done on hard bushes Possible next steps (if agreed): Define a hard, non magnetic and suitable for coating material for the bush Perform cycling tests for final materials

Vacuum study – Accelerating structure No relevant progress since last status: Baseline of a mixed solution between the NEG cartridge pumps (capacitorr) and the NEG cartridge and ion pump (Nextorr). Next step: Evaluate the gas loads induced by the SiC loads. Would a piece of SiC, after all manufacturing process, be available? Diaphragm (pumping speed ~ 1.5l/s) Capacitorr Nextorr

Vacuum study – Main beam quadrupole Test set-up Pump down curve  Pressure down to mbar at the center of the chamber  Higher pressure at the extremity (~ 10-8 mbar): No yet understood  Outgassing tests on individual material and components ongoing  Next test foreseen before summer  Monte Carlo simulation (Molflow) on going to analyze the pressure profile

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 Development ongoing Prototype with 2 convolutions  Manufacturing tooling foreseen in the central workshop  Mock up for RF test in preparation  Fatigue tests can restart (fatigue machine re-commisionned)

Conclusions Tribology tests have been done for the ON/OFF mechanism. Good tribology performance of multilayer TaN coating has been observed. Further tests are possible. Thermal outgassing measurements are foreseen on representative SiC piece. Development of deformable RF fingers are ongoing.