Progress on coatings and grooves M Taborelli Progress
Progress on coatings and grooves M. Taborelli -Progress on C based coatings -Progress on rough coatings -Progress on SEY instrument -Grooves calculation (Pivi, Wang) SPSU 13. 5. 2008
Progress on coatings Carbon deposited with Ne: low yield is reproducible…at least in the same geometry Th ic kn es s pr ob le m The reason of the low yield might be the higher deposition p with Ne SPSU 13. 5. 2008
Progress on coatings Powder, particles and dust Procedure: Before coating: Chamber assembled in coating lab b. 181; Transferred to class 100 clean room in b. 101; Particles measured by “pumping” the chamber with the particle counter. (1 minute runs); Chamber back to b. 181; insert C cathode and perform coating; After coating: Dismount cathode in b. 181; Transfer to clean room in building 101; Measure particles; SPSU 13. 5. 2008
Progress on coatings Powder, particles and dust Results: Particles between 0. 3 mm and 0. 5 mm: run# (min) Particles larger than 0. 5 mm: run# (min) After coating about 10 x more particles. (7. 3 x for 0. 3 mm, 13 x for 0. 5 mm) After gentle hammering no further particles produced. Coated chamber stored under vacuum to check particle evolution after 1 week. SPSU 13. 5. 2008
Progress on coatings Rough Zr coating (fast deposition rate) 1 μm SPSU 13. 5. 2008 100 nm
Progress on coatings SEY or smooth and rough Zr coating: The relative improvement is some 15%. . . which means that coating with a layer having delta=1. 2 would result in a delta of 1 ( …. . a little more complex due to the energy dependence of the effect) SPSU 13. 5. 2008
Progress on coatings and instrumentation Energy dependence of SEY (new instrument) NB: no influence of various applied potentials, means that the system is stable and values of potentials are not critical SPSU 13. 5. 2008
Progress on coatings Black Au: SEY at 500 e. V on smooth and black gold SPSU 13. 5. 2008
Progress on coatings Black gold: Au coating by evaporation in Kr 1 µm SPSU 13. 5. 2008 200 nm
Progress on coatings Black Au, energy dependence: maximum is at very high energy SPSU 13. 5. 2008
Progress on coatings Plans for next coatings (…. find candidate for next liner) -C(Ne) in tube geometry again; still not sufficiently controlled and reproducible -Particle measurement will be done again after some time on the same chamber to see if any “dust” is generated -More controlled black-Au deposition (for the moment the layer is very inhomogenous in thickness) and characterization for vacuum properties (outgassing due to large surface) -C coating on rough surface (Zr) -BC with lower amount of B than B 4 C: coating done, not measured yet -Si. C SPSU 13. 5. 2008
Plans for SEY instrument Still to be done on new instrument: - Control of focussing (at present some 2 mm spot, but not well controlled above 1000 e. V): done -Position (distance) with respect to “optics”: done -Beam position stability at low Ep (below 50 e. V) -Load lock: done -transfer to XPS: will be connected when testing is finished -modify software to measure with scan -SPS transfer chamber Phase II: -Faster acquisition to avoid high dose. . . however it seems to be already OK -Implement flood gun for conditioning with e-beam SPSU 13. 5. 2008
Progress on grooves Grooves, calculation of L. Wang at SLAC on the geometry obtained on copper Reduction also for B=0 so that we can measure in the lab CERN workshop on Copper (S. Atieh, J. M. Geisser) Assuming delta-max=1. 5 15º 1 mm 2 mm B=0. 2 T SPSU 13. 5. 2008 B=0 B=2 T
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