What Ive been doing since last time Working
What I’ve been doing since last time • Working to find if any existing models of geometric impedance give a comparable wakefield reduction to serigraphy on SPS MKE • Moved to France/Switzerland – SNOW! • Many meetings to discuss future direction of work • More paperwork than should be legal Hugo Day - Manchester Monday Morning Mega. Meeting - Cockcroft Institute 15/02/2010
Revision of surface roughness (Wake Field Effects due to Surface Roughness M. Angelici et al) and thin-iris approximation (Wakefields and Impedance Palumbo et al – CAS Advanced School on Accelerator Physics 1994) Hugo Day - Manchester Monday Morning Mega. Meeting - Cockcroft Institute 15/02/2010
(1) Surface roughness (2) (3) Small Iris • Reran numbers, w 0 = 4. 17 x 1012 V/C (4. 17 V/p. C), same as before • 2πf 1 = 431, also reducing w(τ) when integrated. • Similarly, thin-iris approximation is exceptionally small -> Probably not meant for this scale • Will need to find alternative approaches - > See figure 2 of scale of drop from serigraphy Hugo Day - Manchester Monday Morning Mega. Meeting - Cockcroft Institute 15/02/2010
Wake Potential (V/p. C) With Serigraphy Without serigraphy z/m Deviation needs to be on order of 2 -2. 5 V/p. C – gives a scale to work with atleast Hugo Day - Manchester Monday Morning Mega. Meeting - Cockcroft Institute 15/02/2010
Plans for upcoming work (discussed with E. Metral) • Week beginning 22 nd Feb -> Barnes/Caspers will be taking measurements of LHC-MKI with impedance reduction inplace. Will assist in measurements of transverse and longitudinal impedance • Comparison of measurements to simulations of wire measuring technique will be made – Seems likely work will shift to MKI for the time being – Barnes to forward files, currently searching for non-corrupt CAD designs • Also, collimation group meeting today -> Phase II upgrades hold many questions about optimum material composition for low impedance measures. Significant as some maybe inserted in SPS also. SLAC testing at the moment • Elias would like a comparison of time domain/frequency domain results for wire based measurements -> Have time domain from CST MWS, series of tasks to be given for trying with HFSS/Gd. Fid. L • SPS work to be put on hold for the time being, more immediate concerns Hugo Day - Manchester Monday Morning Mega. Meeting - Cockcroft Institute 15/02/2010
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