LC-ABD WP2
This the the published grant statement in PPARC by Andy Wolski before it was taken down in the STFC website. The following is what remains in Google on 21 March 2009:
This is the published statement on the STFC website before it was removed:
Achieving high beam quality in the damping rings will be critical for luminosity production in the ILC. While the beam intensity is somewhat lower than in some modern electron storage rings, the fact that the vertical emittance is smaller by some orders of magnitude means that the damping rings will be much more sensitive to effects that limit beam stability. In addition, tuning and operation of the downstream systems will be completely dependent on extraction of highly stable beam from the damping rings. A wide variety of effects impact beam quality and stability in electron storage rings. We propose an integrated programme of studies addressing key dynamical effects that are closely associated with the design of the vacuum system. An essential component of this programme will be studies and design work for the vacuum system itself: there is considerable expertise in this area within ASTeC and CCLRC which we shall use, thereby strengthening the UK's skill base in a field that is critical for all accelerator development. By working in collaboration with other laboratories (for example, LBNL) we will provide sufficient coverage of the vacuum system design and analysis to ensure that the beam stability specifications for the damping rings can be achieved. In particular, we will work on the arc cells in the damping rings: although each cell is relatively small and straightforward, altogether the arc cells account for 70% of the circumference of the lattice. In addition to the design work mentioned above, there is a need for basic R&D on the vacuum systems. For example, additional data on the properties of NEG (non-evaporable getter) coatings and effective activation procedures must be obtained if a cost-effective vacuum system is to be produced, which meets the specifications for performance (during commissioning and long-term operation) in terms of vacuum level and surface properties. The vacuum systems are a key component in the ILC damping rings. In the present baseline configuration, the total length of beamline is 20 km, and by taking a central role in the design studies for the vacuum systems during the TDR, the UK will be well positioned for making a significant contribution to the damping rings during construction and operation of the ILC. These studies also fit well within the broader UK programme of studies for the beam delivery system, where the vacuum systems are also critical to the performance of the machine. The studies and design work for the vacuum systems are interdependent with detailed understanding of the beam dynamics in the damping rings. Effects such as injection/extraction transients, resistive-wall instability and microwave instability potentially limit the damping rings performance, and close collaboration will be required between those working on the vacuum system design and those modelling the beam dynamics, if the beam stability goals of the damping rings are to be achieved. We propose to perform studies of the beam dynamics effects in the damping rings that are closely connected with the design studies for the vacuum systems. The goal will be to understand the operational limits on parameters such as the beam current and bunch length, and to set well-founded specifications for technical systems such as the fast feedbacks and the instrumentation and diagnostics. Effects with the potential to limit beam quality and stability in the damping rings cannot be treated in isolation, so a meaningful programme of studies on beam quality and stability will include effects ranging beyond those directly driven by the vacuum system. For example, a major issue for the ILC damping rings will be achieving and maintaining the specified vertical emittance, which is a factor of two smaller than the lowest achieved in any existing storage ring. Our proposed work package includes studies that will directly address this issue.
Last modified on 21-3-09