1. M.Taborelli Outgassing of a-C Aging Differences in SEY and aging Preparation for magnet coating Progress on a-C coatings Ch. Yin-Vallgren, S.Calatroni, P. Costa Pinto, P.Chiggiato, H.Neupert, I.Wevers

2. M.Taborelli Pressure gauge Turbo-molecular pump Tube with coating =sample Pumpdown measurements Log(Time) Log(Pressure) Is a measurement of the outgassing of the wall of the tube calibrated conductance

3. M.Taborelli Pumpdown curve of a coated tube compared to StSt tube StSt Liner (CNe8 second SPS liner) 1 month air Time[s] 10 2 10 3 10 4 10 5 10 6 a-C tube CNe20, 1h air 10 -2 10 -3 10 -4 10 -5 10 -6 10 -7 10 -8 Pressure [Torr] a-C tube CNe18, 1h air a-C tube CNe12 1h, 1d, 1week air Pumpdown after air exposure

4. M.Taborelli Aging upon air exposure (samples measured only once, no cumulative dose) Red and similar circles are liners Blue and similar triangles are tubes Coatings deposited in tube configuration age faster!

5. M.Taborelli Tube versus liner: LinerTube T substrate + - Energy of impinging atoms + - Impact directionmanynormal Observed roughness + - Liner configuration graphite rod Tube configuration graphite rod Liner tube Magnetron sputtering configuration

6. M.Taborelli

7. SEY of a-C in tube and Liner configuration Red and similar circles are liners Blue and similar triangles are tubes Emax tubes Emax liners -All the tubes have lower E max and decrease faster at high Ep -Most of the liners have higher E max and more flat dependence on Ep This would be consistent with rougher coatings in the liners Energy [eV]

8. M.Taborelli grooves Sample from M.Pivi SLAC, macroscopic grooves on Al (measured with beam scan) -grooves made at CERN workshop on copper gave 20% decrese - no success for the moment from trials made at the CERN workshop on StSt 35% decrease

9. M.Taborelli Progress on prototype coating -design approval by end of the week -some delays foreseen in the installation due to restructuring of the coating facility at Bdg181 (LHC quadrupole repair)

10. M.Taborelli Next: Coatings -change coating parameters (p, power, T …) to get a clear picture of the origin of the differences in the coatings of tubes and liners -degassing rate measurements for various gases -measurement of Ne content by laser ablation in UHV and mass spectrometry Prototype coating of an SPS magnet: -Ordering components for pumping system -Drawing to be approved this week