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

2. 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

3. 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
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

4. 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

5. 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

6. 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

7. Thanks for your attention
J. Guardia

8. Backup slides
J. Guardia

9. 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
Total (mbar.l/s)
>
EDMS / (2) EDMS / (3) EDMS / (4) EDMS Under Approval
Vacuum requirements (EDMS , EDMS )
< 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

10. 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