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LIU-SPS e-cloud contribution to TDR

LIU-SPS e-cloud contribution to TDR. First draft by end of February 2014. Between 5 to 10 max pages per chapter, refer to existing publications Proposal concerning electron cloud Simulation study of SPS chambers  ECLOUD12 paper summarizes the outcomes Experimental activities at SPS

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LIU-SPS e-cloud contribution to TDR

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  1. LIU-SPS e-cloudcontributionto TDR • First draft by end of February 2014. Between 5 to 10 max pages per chapter, refer to existing publications • Proposal concerning electron cloud • Simulation study of SPS chambers  ECLOUD12 paper summarizes the outcomes • Experimental activities at SPS • Beam quality studies, signal from e-cloud monitors, experiment with a-C coated pipe and solenoids at both ends to explain pressure rise  all described in the note published last year, CERN-ATS-Note-2013-019 MD needs to be compressed in few pages • Doublet beam tests (optimized scrubbing)  IPAC paper • Future plans (post-LS1, strategy coating vs. scrubbing)  Hannes’ paper from RLIUP Electron cloud meeting, 17/02/2014

  2. Future studies (SPS) • Simulations • Simulation of main quadrupoles QD and QF (SEY threshold) • E-cloud monitors (including the holes) • COLDEX – meeting with TE/VSC colleagues to define the needs • Instability thresholds with all chambers (MBB, MBA, QD, QF, SS1, SS2)? • Experimental activities at SPS (scrubbing run 2014 + MDs) • 25 ns beam(standard and BCMS) • Recover 2012 performance • Push performance to maximum intensity (possibly higher brightness thanks to the PSB-PS larger longitudinal emittance transfer), • Monitor scrubbing process based on e-cloud observables (liners, beam lifetime, emittances, tune shift along the train, chromaticity needed to stabilise). • Characterization of the a-C coated cell. In-situ SEY measurements device? • Doublet beam, full set up (need to set up slower acceleration cycle, Q20 and Q26) • High Bandwidth Feedback System tests on single bunches of a multi-bunch beam (using directly data with ECI, if possible) • Test 8b + 4e scheme (e-cloud efficient ?) • COLDEX measurements with cold a-C coating (probably in 2015?) Electron cloud meeting, 17/02/2014

  3. Injectorschedule 2014 Electron cloud meeting, 17/02/2014

  4. Future studies (LHC) • Simulations (no experiments in 2014) • Simulation of all SAMs and semi-SAMs (SEY threshold) • Comparison with heat load data to determine • Evolution of SEY • Present value of SEY • Heat load in dispersion suppressor to determine fractions of e-cloud in arc dipoles and quads • Comparison with stable phase shift measurements including alos the contribution from arc quads + SAMs + semi-SAMs • Extract all the heat load data from ITs (2011 – 2013) • Define a strategy to determine the scrubbing history with both 50 and 25 ns beams (simulations of some selected points) • Project for summer student submitted • Simulation of higher order magnets (sextupoles, octupoles) • Do we need to include also the drifts in all our comparisons with heat load data? (usually cryostats include long drift portions) • Holes in the beam screen: effect in dipoles ? • E-cloud in BSRT chamber? Can we change the magnetic field and measure heat load? • Stability for different octupole polarities (to explain hunchback instability) Electron cloud meeting, 17/02/2014

  5. Future studies (PS) • Simulations • Simulation of the new e-cloud monitors in SS98 (expected signal) • Instability simulations ?  self-consistent approach needed, maybe start with concatenating PyECLOUD and HEADTAIL (how easy through cobra-HEADTAIL?) • Experimental activities at PS • Measurements with the new monitors installed (25 and 50 ns, different bunch lengths over the last part of the cycle) • Cover higher intensities, up to LIU values, if achievable after LS1 with the new longitudinal feedback • More instability data? • New Technical student will start in March 2014  Annalisa Romano Electron cloud meeting, 17/02/2014

  6. Future studies (Miscellaneous) • More LHC and HL-LHC studies • BGV, MKI, TDI, BSRT … • HL-LHC  Triplets in IP2 and IP8, include D1 with new triplets in IP1 and IP5, SAMs from matching sections  April • CLIC damping rings • Check electron cloud in the electron ring for the rebaselining? (possible resonant values for which there could be electron accumulation even in electron ring) • Check for cyclotron resonances in wigglers? (scan in magnetic field between -2.5 and 2.5 T) • FCC • Define possible electron cloud issues in the FCC and injector chambers (defined by magnet and resistive wall constraints) • Scan over bunch intensities and spacings under consideration Electron cloud meeting, 17/02/2014

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