Experimental Interaction Region Andrei A Seryi JAI Rogelio

Experimental Interaction Region Andrei A. Seryi (JAI), Rogelio Tomas (CERN) On behalf of Euro. Cir. Col WP 3 EIR design team: CERN, CI, EPFL, INFN, JAI General design meeting 13 April 2017

Request • Please consider that these are not supposed to be complete presentations, but rather a brief summary of the points that will be addressed in your talk: – 1) Scope of studies foreseen for CDR. Which key issues will be addressed? – 2) Status of studies. What will still be done for Berlin, what for the CDR. – 3) Key conclusions. Strengths and weaknesses of the design. Further R&D to be carried out after CDR. • The plan/response shown on the next slides is tentative and will evolve Experimental Interaction Region, 13 April 2017, A. Seryi 2

Key conclusions & plans • EIR optics – Optics can be designed, for 0. 3 m beta* with good clearance and shielding – Lower beta* (0. 15 -0. 2 m) possible w reduced clearance – Flat optics (for w/o crab cavity) possible too – can run round or flat – Two versions of triplet (both satisfy magnet reqs of <15 m) – Can fit to given 1400 m easy for one, and to about 1450 m for another (if it remains, it will require stronger bends in arcs) – Further optimisation may benefit from reducing L* but this require dropping dipole bend spectrometer from detector option – It may be good to have wide discussion & decision about that at Berlin review and therefore to plan to make one more iteration on L* and optics optimisation after Berlin Experimental Interaction Region, 13 April 2017, A. Seryi 3

Key conclusions & plans • EIR optics, errors, correctors & DA – Triplet errors and offsets effect can be corrected – Effect of ring and EIR errors on DA presently studied – steady progress in DA improvement – DA optimization is a challenging task across the WPs, which depend on accurate orbit and dispersion correction in the ring, on nonlinear correctors, etc – Present status of min DA w/o nonlinear correctors is about 2 sigma, and much more with correctors – Status will be shown in Berlin, will likely need to continue optimisation after Berlin too Experimental Interaction Region, 13 April 2017, A. Seryi 4

Key conclusions & plans • EIR energy deposition and triplet protection – – Triplet can be protected Detailed studies have been performed Adequate shielding can be provided Further optimisation will continue after Berlin, as the optics may still evolve (version selected, L* may change, ultra ultimate beta* defined) – Protection of other elements such as D 1 and D 2 will still need to be studied after Berlin Experimental Interaction Region, 13 April 2017, A. Seryi 5

Key conclusions & plans • EIR cross IP muons and protons – Muon cross talk studied analytically and in monte-carlo – There is no concern, muons reach only half-way between Ips – This will then likely conclude at Berlin – Study of elastic and inelastic protons from IP and how they affect arcs and other IP possibly taking into account crabbing and other effects – the expectation is that this can be mitigated – studies will be reported at Berlin – These studied will likely need to be continued after Berlin Experimental Interaction Region, 13 April 2017, A. Seryi 6

Key conclusions & plans • EIR SR photons background – Studies have been done and it was confirmed that this is not a big concern – This will be reported at Berlin and will then likely conclude at Berlin Experimental Interaction Region, 13 April 2017, A. Seryi 7

Key conclusions & plans • EIR beam-beam studies – Various preliminary studies have been done – These studies depend a lot on having a full optics with good DA so that B-B can be studied with most realistic assumptions – Some preliminary studies will be reported at Berlin and will then continue after Berlin Experimental Interaction Region, 13 April 2017, A. Seryi 8