Damping Rings form a critical part of the injector complex and are responsible for producing the tiny vertical emittances critical to obtaining high luminosity. The stringent requirements on cross-plane coupling compensation, residual vertical dispersion and fast damping times, are beyond that currently achieved in modern storage rings (light sources). Following the ILC-TRC recommendations, the DR WP has chosen to address the following critical R&D: theoretical (simulation) and experimental studies on the electron cloud phenomenon, including R&D towards suppression techniques; study possible applications of RF separators to the ILC DR injection/extraction; study the effect of wiggler fields non linearity on Dynamic Aperture; simulation studies of low emittance tuning algorithms, including possible experiments in existing rings.
ECLOUD - Study of e-cloud and other instabilities
Objective: to evaluate the impact of e-cloud and fast ion instability on DR performance and propose suppression techniques
• Experimental verification of e-cloud build-up and instability simulation codes
• Application to DR design
• Simulation of fast ion instability
• DR vacuum design
• NEG coating studies
LETS - Low emittance tuning studies
Objective: to study and define low emittance tuning procedures
• Review of existing techniques
• Develop and implement novel BBA (Beam Based Alignment) techniques
• Machine trials of tuning algorithms (for example in PETRA)
• Comparative study of different DR lattices
• Define requirements for beam diagnostic
• Report on final recommendations
RFSEP - RF Separator studies
Objective: to study the feasibility and the efficiency of RF separators for bunch train compression
• Study the application of multifrequency RF deflectors to the DR injection/extraction scheme
• Evaluate the possibility of compressing the bunch time distance at injection by a factor ~20 (as needed for the TESLA DR)
• Evaluate the possibility of a larger compression factor which would allow a shorter DR
• Study other possible applications (e. g. orbit feedback)
• Simulate the injection/extraction process including errors
• Perform the engineering design
• Evaluate the contribution to DR impedance
WGLRDYN - Wiggler modelling and beam dynamics
Objective: Study the effect of wiggler fields nonlinearity on wiggler DA and optimize the DR acceptance .
• Refinement of nonlinear Wiggler models for tracking simulations.
• Verification of models against experimental data.
• Evaluate Dynamic Aperture (DA) of DR.
• Optimize the wiggler design to improve DA
• Optimize the lattice to improve DA
• Evaluate Dynamic Aperture of optimized DR design.
Susanna Guiducci, INFN-LNF