In-Situ Secondary Electron Yield Measurements for C ESR TA: Update W. Hartung, C. Dennett, V. Omanovic, Y. Li, T. Moore for the C ESR TA Collaboration C ESR TA Collaboration Meeting ● 22 January 2013

In-Situ Apparatus 22 January 2012SEY Update--CesrTA Collaboration Meeting2 45° Station Horizontal Station Beam Pipe TiN- coated sample “Beam’s eye” view

SEY Samples 22 January 2012SEY Update--CesrTA Collaboration Meeting MaterialDatesComments TiN 1st pairJan 2010-Aug 2010Samples from SLAC AlAug 2010-Nov T6 alloy Amorphous CNov 2010-Jan 2011Coating by CERN Diamond-like CSep 2011-Nov 2011Coating by KEK TiN 2nd pairNov 2011-Mar 2012Samples from SLAC CuMar 2012-Jul 2012OFC 101 Stainless steelAug 2012-Oct series TiN 2nd pairOct 2012-Jan 2013Recondition after air exposure AlJan alloy 3

Beam conditioning: Peak SEY 22 January 2012SEY Update--CesrTA Collaboration Meeting4 Beam conditioning of SEY samples (center, inc. angle = 25°) Horiz. 45°

Beam conditioning: Peak SEY 22 January 2012SEY Update--CesrTA Collaboration Meeting5 Conditioning vs reconditioning: TiN (center, inc. angle = 25°) Horiz. 45°

Conditioned Samples 22 January 2012SEY Update--CesrTA Collaboration Meeting6 SEY vs energy after conditioning (center, inc. angle = 25°)

Beam conditioning: SEY vs position 22 January 2012SEY Update--CesrTA Collaboration Meeting7 Beam conditioning vs azimuth (inc. beam = 405 eV, 25°) Stainless steel TiN after air exp.

Conclusion 22 January 2012SEY Update--CesrTA Collaboration Meeting8 Work in progress/plans –Monitor SEY vs time after conditioning, with samples in vacuum (done for Cu and reconditioned TiN) –Remeasure SEY in Blue Room after exposure to air –Interpret results so far; correct for systematic effects and connect measurements to SEY models, including SEY vs incident angle and SEY at low energy –Near term: measure Al-6063, then new amorphous carbon samples