Workshop on Accelerator R&D for USR Closeout Remarks for Accelerator Physics Session

Tasks: - Identify and prioritize Studies and R&D to be pursuit in the Short and Mid Term - Identify Groups and Labs that will perform them - Establish as much as possible a network between groups to share resources and results All of the above have been happening already, the workshop is just the opportunity to refresh/update/enforce those tasks (and find out what’s missing)

Collective Effects (Well covered by most everyone): - Impedance *** Calculations Scaling Laws Emittance degradation (when?) - IBS**** - Ions Instability ** - Toschek Lifetime***** - CSR ** - Space Charge* ( * = effort/knowhow) Make sure all codes/formulas are benchmarked among Labs… Establish More Tests to be perfomed in existing facilities to reproduce parameters of interest as much as close to the USR ones. For example by lowering the Energy of the Higher Energy SR: Spring8? Petra? ESRF? ???

Make Round Beams: Ex&Ey => (Ex/2+a*Ey)&(Ex/2+(1-a)*Ey) : - Explore and study different solutions Equal tunes Skew Quads Solenoids Vertical Dispersion Vertical wigglers etc…. - Identify sites where to make tests (some additional hardware might be needed: Skew quads, Solenoids etc…) Diamond? ??? Low Momentum Compaction (common to most designs): - Identify sites where to make tests in conditions as close as possible to USR- UserMode (some additional hardware might be needed: Harm Cav, Streak Cameras etc) Diamond? New Subaru? ???  Increase Momentum Compaction with chicanes (Lattice Design)?

Items linked (and/or covered) to Lattice Design Optimal Energy: - Need general scaling laws that take into account as much as possible all the effects Emittance (including collective effects) Brightness and Spectrum Circumference Magnets Running costs? Etc… Coupling Correction (in Flat Beams mode): Well Established KnowHow and procedures, seem already ok for USRs Need to control Ey without adding (too much) coupling “White Noise” excitation

Items linked (and/or covered) to Lattice Design Optimal RF Frequency: - Need general scaling laws that take into account as much as possible all the effects HOM RF Power Energy Acceptance Bunch Length Size Cost Running costs? Second RF freqeuncy Etc… Same for Warm vs SC Technology Best solutions conditioned by the existing Hardware/KnowHow at different sites

Items linked (and/or covered) to Lattice Design Ids Effects: - Lattice sensitivity to IDs perturbations Orbit Beta Mismatch Dynamic Aperture Energy Spread Increase Impedence Increase (linked to IDs Engineering) Dynamic Aperture - Iterate with previuos items that can alter or constrain it….