TCSPM Prototype Coating feasibility J. Guardia Valenzuela, A. Lafuente EN/MME 10.05.2016

Background TCSPM prototype to be installed in the LHC end-2016 Blocks will be made from MoGR and possibly coated with several materials to reduce impedance Production of 6 blocks made of MG-6403-Fc ongoing. Remaining blocks + taperings grade to be decided after this meeting. In order to meet aggressive schedule, coated blocks needed by September 2016. Transversal mobility of the jaws by +/- 10mm, available to offer a fresh surface to the beam in case of damage In this framework there is a need to confirm: UHV compatibility of the chosen MoGR grade If and which coating materials can be used (Mo, Cu and TiN) J. Guardia - 27.05.2016

Mo Coatings Mo coating evaluation included: Validation for Mo on MoGR currently going on real block. Full surface coated on Mo to be able to measure impedance Comments CFC Graphite Roughness measurements Ra 6.4 Ra 1.6 CO2 blasting Small variations/Uncertainities Coating - Impedance measurements ~14MS/m Vacuum firing 1000°C @ 2 h Outgassing tests 3x reduction observed ~13MS/m ~8MS/m Adherence tests Good adherence for both scotch test and pat handy test J. Guardia - 27.05.2016

Cu Coating Cu characterization is mostly based on previous work done for TCDI/TCDQ Spare blocks from TE/ABT tested for impedance and compared with recently extracted ones Additional adherence tests conducted on 3-stripe trial showed results comparable to those of Mo J. Guardia - 27.05.2016

TiN Coating 0.03 MS/m 6.8 MS/m 0.13 MS/m 5.5 MS/m Trials done on CFC and graphite in collaboration with Danish Institute DTI Initial adherence issues observed CO2 blasting the surfaces prior to coating eliminated the problem Outgassing tests not conducted in due time. Still relevant? Impedance measurements reveal discrepancies with expect values Next steps? 0.03 MS/m 6.8 MS/m 0.13 MS/m 5.5 MS/m 2-2.5x lower than TiN theoretical [1] [1] Handbook of refractory compounds G.V. Samsonov 1980 TiN: 400nΩm / 2.5MS/m J. Guardia - 27.05.2016

Coatings current status Several coatings have been explored. Main candidates: TiN hardly compatible with prototype schedule Trial coatings of Cu and Mo have been done on graphite and CFC A thorough evaluation has been done for Mo Cu characterization based on previous work done for TCDI/TCDQ plus some adherence tests recently done Impedance measurements performed on 3-stripes coated CFC block Cu Mo TiN J. Guardia - 27.05.2016

Thanks for your attention J. Guardia - 27.05.2016

Backup slides J. Guardia - 27.05.2016

MoGR latest outgassing results Latest MoGR results evince an improvement RGA results for the last two analyses reveal a shift of the maximum outgassing contributor from N2 to H2 Two more test scheduled to start next week A dedicated student and test bench are envisaged for the near future MG-3110-P MG-6530Aa (1) MG-6530Aa (2) MG-6403X(3) MG-6403Fc (4) 950°C 2h vacuum 48h Vacuum As received 12h Relative (mbar.l/s/cm2) > 10-10 1.7 10-10 3.6 10-10 7.6 10-10 3.9 10-11 3.3 10-11 Total (mbar.l/s) > 5 10-7 7.8 10-7 1.7 10-6 3.5 10-6 1.6 10-7 1.5 10-7 EDMS 1547420 / (2) EDMS 1555116 / (3) EDMS 1605495 / (4) EDMS Under Approval Vacuum requirements (EDMS 428155, EDMS 1312756) < 10-12 mbar.l/s.cm2 < 10-7 mbar.l/s after 24h at 250°C Extrapolated results for the total absorber area are only marginally above limit for collimator Non-controlled MG6403Fc block Outgassing test under gas injection In the light of these results block production has been approved by TE-VSC J. Guardia - 27.05.2016

Preliminary Schedule Assumptions: Coated blocks are tested for vacuum conformance in batches of 6 as agreed with TE-VSC Blocks are coated with Cu and Mo 4 week stop in August J. Guardia - 27.05.2016