1. CLIC Re-baselining CSC, October 2012

2. Possible CLIC stages studied 2

3. Outlook on Staging Iterate on the energy stages – Proposal is to have 375GeV, ~1TeV and 3TeV Seems to find support from physics – Would cover the top with the first stage – Increases energy by factors of three from there The staged approach has not been optimised – Particular emphasis required on the first stage And on the upgrade paths – Need an improved cost model Covering the first stage And the upgrade paths – Need to review the cost Evaluate the proposed cost saving options Identify cost drivers Develop models how they affect the overall cost – Need a power consumption model

4. Cost of the 500GeV Stage Swiss francs of December 2010 Incremental cost for B: 4MCHF/GeV -> Step to 1.5TeV is less than first stage D. Schulte 4 CLIC staging, LCWS October 2012

5. Power Consumption 3TeV 5 CLIC staging, LCWS October 2012D. Schulte We optimised this part Largest contribution Strongest dependence on structure design Best understood at the time

6. Power Consumption 500GeV (A) 6 CLIC staging, LCWS October 2012D. Schulte We considered this part, which is now a much smaller fraction Need to review power consumption in many places Options for savings exist

7. Goal Have a plan before LCWS Have some first results before CLIC workshop in January – Improved understanding of the drive beam-based staged approach Updated cost/power model Identified cost saving options Understanding of studies to be done for cost saving – Have some design for a klystron-based first stage Have an optimised staged design – With alternatives – With defined R&D to validated design

8. Strategy Need to include the civil engineering cost with each area if it is affected by the design choices – E.g. cost of drive beam accelerator buildings add to the drive beam cost – E.g. cost of the main linac tunnel add to the cost of the main linac length Most expensive systems are – Main beam generation – Drive beam generation – Main linacs In a first round should address each of these system on a high level – Have small groups look at each system and report to this meeting And one group to look into klystron-based first stage

9. Simplified Diagram Drive Beam Generation Complex P klystron, N klystron, L DBA, … Main Beam Generation Complex P klystron, … Two-Beam Acceleration Complex L module, Δ structure, … I drive E drive τ RF N sector N combine f r N n b n cycle E 0 f r Parameter Routine Luminosity, … E cms, G, L structure VariableMeaningCurrent value I drive Drive beam current101A E drive Drive beam energy2.37GeV τ RF Main lianc RF pulse length244ns N sector Number of drive beam sectors per linac 4 N combine Combination number24 frfr Repetition rate50Hz NMain beam bunch charge in linac 3.72e9 nbnb MB bunches per pulse312 n cycle Spacing between MB bunches 6 cycles E0E0 MB energy at linac entrance 9GeV E cms Centre-of-mass energy500GeV GMain linac gradient100MV/m

10. Discussion Animators They should help to initiate and animate the discussion in smaller groups Report to the re-baselining working group Four animators are – Main beam sources: Yannis Papaphilippou – Drive beam generation: Roberto Corsini – Two-beam acceleration: Alexej Grudiev – Klystron-based first stage: Igor Syratchev Please contact them with any good idea 10

11. Some Examples of Saving Options for Current Design Cost – Alternative main linac structure fabrication – Longer main linac modules – Maybe do not need electron pre-damping ring – CVS overdesigned for 500GeV – Main beam sources RF power quite high – Shorter drive beam pulses in first stage can reduce cost of modulator (modular design) – Combining pairs of drive beam accelerator klystrons – Using cheaper copper type in drive beam accelerator structure – Cost impact of 1GHz damping ring RF – Cost impact of long main beam pulses for low energy operation – … Power – Permanent drive beam turn-around magnets – … For many items need R&D since choices were made for a reason 11 CLIC staging, LCWS October 2012D. Schulte

12. Conclusion Started with the re-baselining process – Explore cost/power reduction options – Develop better cost/power model – Will use that to optimise parameters – And optimise the design Next meeting on November 23 First results will be presented at the CLIC workshop January 2013 12