Review of FCC tunnel footprint & implementation Introduction & scope Philippe Lebrun Review of FCC tunnel footprint & implementation CERN, 11 June 2015

Timeline of the FCC study Ph. LebrunReview of FCC Footprint Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 Explore options “weak interaction” Report Study plan, scope definition FCC Week 2018  contents of CDR CDR ready FCC Week 2015: work towards baseline conceptual study of baseline “strong interact.” FCC Week 17 & Review Cost model, LHC results  study re-scoping? Elaboration, consolidation FCC Week 2016 Progress review

Scope The FCC Conceptual Design Report (CDR) should –provide a consistent description of a future FCC complex, –address main design and construction challenges, –present possible – if not optimized – configurations, with a level of detail sufficient to perform quantity, schedule and cost estimates In order to proceed towards the writing of the CDR, it is necessary to converge on the technical baseline of the report, starting with the tunnel footprint and implementation. Ph. LebrunReview of FCC Footprint

Questions for the review [1/2] 1. What are the high-level performance parameters to be achieved by FCC-hh and FCC-ee for the CDR? 2. What is the perimeter and configuration chosen for the tunnel and are these choices appropriate? (arc bending radius and filling factor, number and lengths of Long Straight Sections (LSS) and Extended Straight Sections (ESS), limits set by geographical and geological features). 3. To which functions are the LSS and ESS allocated? Where are the physics experiments? Are these choices optimum or could they be improved? 4. The minimum distance between clustered collision points is given by the minimum angle between the IPs to avoid crosstalk. What closest spacing of IPs can be considered? 5. There seems to be a preference from experiments to have all IPs as close as possible to the main CERN site. Is this feasible and how does it impact on layout? 6. Is there a need for separate accelerator tunnels bypassing the experiments? Can the injector machine(s) also pass through the detectors/experimental caverns? Ph. LebrunReview of FCC Footprint

Questions for the review [2/2] 7. Specifically for FCC-hh, what is the length of the short Technical Straight Sections needed to accommodate the end-of-sector cryogenic and electrical equipment? 8. Specifically for FCC-ee, how many LSS/ESS need to house SCRF cryomodules? Over what length(s)? What is the staging model for SCRF cryomodules and for the cryogenic plants serving them? 9. What are the constraints/drawbacks/benefits on tunnel depth, slope, non- planarity coming from a) geography, geology and civil engineering, b) accelerator physics, c) accelerator systems, d) utilities, e) safety, f) environment? 10. What injection options are considered? How do they impact the configuration, slope, non-planarity, location of the tunnel? 11. How are the beams disposed of? What are the corresponding requirements on tunnel configuration? 12. Given the answers to the preceding questions, what appears to be the optimal position of the tunnel? Ph. LebrunReview of FCC Footprint

Outside the scope of this review Transverse cross-section of tunnel (single vs. twin tunnels, safety tunnel, safety area in single tunnel) Local tunnel singularities, e.g. stub tunnels for housing equipment Number, size & configuration of experimental and technical caverns Number, size & configuration of shafts and/or access ramps Number, size & configuration of technical areas at ground level Ph. LebrunReview of FCC Footprint

Reviewers Austin Ball Paul Collier Massimo Giovanozzi Philippe Lebrun (chair) Lluis Miralles Ralf Trant Ph. LebrunReview of FCC Footprint