1. review of FCC-hh optics & beam dynamics IPNO, Orsay, Paris 19-20 November 2015 Reviewers: S. Fartoukh (CERN), O. Napoly (CEA), E. Todesco (CERN), F. Zimmermann (CERN, chair ) Work supported by the European Commission under the HORIZON 2020 project EuroCirCol, grant agreement 654305 02/12/2015F. Burkart1

2. review agenda Time (19.11)lengthtitlespeaker 14:00Welcome and review goalsMichael Benedikt 14:00-14:2020 min.Arc lattice, lattice integrationAntoine Chance 14:20-14:4020 min.IR latticeAndrei Seryi 14:40-14:5010 min.Minimum separation of detectorsRob Appleby 14:50-15:0515 min.Collimation system requirementsStefano Redaelli 15:05-15:2015 min.Betatron& momentum coll. latticesAntoine Lachaize 15:20-15:4020 min.Collimation tracking & evaluationJames Molson 15:40-16:1030 min.Discussion 16:10-16:3020 min.Coffee break 16:30-16:4515 min.Injection lattice sectionFlorian Burkart 16:45-16:5510 min.Integration of RFBernhard Holzer 16:55-17:1015 min.Extraction/dump lattice sectionFlorian Burkart 17:10-17:3020 min.Errors,tolerances,corrections DABarbara Dalena 17:30-18:0030 min.Overall layout & optimizationDaniel Schulte 18:00-18:3030 min.Discussion Time (20.11)lengthtitleSpeaker 09:00-11:00120 min.Executive session (closed)reviewers Additional invitees: WP2 and WP3 participants, R. Aleksan (ECB chair) 02/12/2015F. Burkart2

3. 1.review the design status and performance of all dedicated insertions 2.review the overall lattice integration and space allocation/optimization 3.review the performance of the integrated lattice in terms of dynamic aperture, error tolerances etc. 4.identify any areas with optimization potential and propose high-priority actions towards the next milestone, FCC week Rome in April 2016. review goals 02/12/2015F. Burkart3

4. Review of FCC-hh optics & beam dynamics Extraction lattice section 19. / 20. November 2015 Input from M. Barnes, W.Bartmann, M.Benedikt, F.Burkart, B.Goddard, W.Herr, T. Kramer, A. Lechner, D. Schulte, L.Stoel 02/12/2015F. Burkart4

5. Beam extraction concept and optics. Dilution kicker requirements. Beam dump line geometry. Conclusions Outline 02/12/2015F. Burkart5

6. Extraction straight options Too tight. R2E. MKB parameters. Too tight. R2E. MKB parameters. 02/12/2015F. Burkart6

7. “Conventional” beam extraction system, 1 per beam. Segmented kicker system Try to minimize frequency of asynch. dump by accepting a single switch erratic – Reduce beta function (in bending plane) at the kicker to limit the oscillation from an erratic – Increase beta function at septum to have better kick efficiency (trade off with septum width) and to have beam dilution for protection absorbers up- and downstream of the septum Asymmetric in optics functions.  638 m central drift Concept 02/12/2015F. Burkart7 Enlarged quadrupole Triple chamber quadrupole? MKBH MKBV Kicker 0.13mrad Kicker 0.13mrad Septum 1.7 mrad, 1.42 T Septum 1.7 mrad, 1.42 T

8. HW parameters LHC scaledKickerSeptum B.dlT.m2 - 2219 - 284 Available system lengthm100200 Rise timeus3- Flat top lengthus>340 GFR h/vmm18/18 Aim for 1 us due to absorber limits 02/12/2015F. Burkart8

9. To be studied for FCC week in Rome: – Impact of ~ 1 sig oscillation for one turn on machine? Beam-beam kick Collimation system Showers …? – Impact on absorbers during a sweep (max. bunch separation required  short kicker rise time). – Also interesting for segmentation of kicker system. To be studied 02/12/2015F. Burkart9

10. Beam dump line geometry 1.4 km dump insertion2.8 km collimation insertion 2.5 km dump line Kicker Septum 10 mrad bend Dilution Absorber 2 – 2.5 km dump line (for dilution system / drift) 10 m diameter dump cavern Need some physical separation between FCC tunnel and dump cavern – say 5 m. Separation between FCC beam and dumped beam of about 15-20 m after 2 km: – 10 mrad fixed deflection in dump line – Needs ~100 m of 16 T dipole at 167’000 Tm – Without 10 mrad, dumped beam is only about 0.7 m separate in H from FCC circulating beam, after 2 km (collimation). 02/12/2015F. Burkart10

11. 1.4 km dump insertion 2.6 km passive protection Septum bends in the vertical plane. Long dump line would help dilution kicker. Reduced radiation impact to electronics as only passive protection for failure cases. Separation for dump block cavern needed. Asymmetric optics for both sides of the LSS. Might be better to have RF with injection. Beam dump line geometry RF 1.4 km dump insertion 2.6 km passive protection 19/11/2015F. Burkart11 “Baseline 2”

12. Hydrodynamic tunneling simulation benchmark with HiRadMat experiment and simulations with FCC beam parameters 12 Beam dump considerations 02/12/2015F. Burkart

13. 90.400 K 120.000 K Beam dump considerations Copper after the impact of 10 and 50 FCC bunches Simulation results for FCC beam parameters show that the beam will penetrate ~ 300 m in Copper, assuming no dilution.  Dilution required! 02/12/2015F. Burkart13

14. Fixed dilution frequency: f = 50.9 kHz Maximum amplitude at the dump block: 80 cm Bunch separation > 1.8 mm Branch separation: 4 cm Max deflection: 0.32 mrad B.dl = 53 T.m Alternative with frequency change: f = 20.4 kHz – 42.9 kHz Bunch separation = 1.9 mm constant Branch separation = 4 cm Max deflection = 0.24 mrad Max amplitude = 0.59 m Bdl = 39 Tm (2.5 km dump line) Energy deposition studies by FLUKA (A.Lechner & P. Garcia) Max. temperature below ~ 1500 °C. Dilution pattern was evaluated as a function of dilution kicker magnet MKB parameters and energy deposition on the TDE. 02/12/2015F. Burkart14

15. Dilution kicker system 02/12/2015F. Burkart15 Horizontal and vertical kicker system as in the LHC ~45 horizontal kickers ~110 vertical kickers within ~ 300 m to be optimized Challenging part of the extraction system as “full” beam rigidity to be handled. Magnet aperture increases with system length due to beam deflection,  reduced efficiency of the magnets. Electronics close to the magnets  no collimation close or upstream of the system. Optimization started, increased lever arm (length of the dump line) would help the dilution kickers, additional help with quads in the dump line. Detailed studies discussed in the FCC dump meetings

16. “Conventional” beam extraction system, 1 per beam. Optics for extraction asymmetric. Optics for combined extractions to be studied. Dilution kicker magnet requirements studied - system is challenging.  FCC beam will penetrate ~ 300 m in Copper without dilution.  Failure modes to be studied.  long lever arm / dump line would help the dilution kickers. Study the impact on machine for sweep and 1 sigma oscillation. – Collimation – Showers in the arc – Impact on kickers, triggering lines… – Energy deposition on septum protection / absorbers. – Need for (and design of) sacrificial absorbers. R2E to be studied. Studies for Baseline 1 (extraction and beta-collimation) and Baseline 2 (separate collimation and extraction) to be followed up. Baseline 2 preferred. Summary 02/12/2015F. Burkart16

17. general remarks enormous progress after only half a year of EuroCirCol project ultimate optics parameters appear within reach tools and algorithms ready (IR debris, collimation efficiency, magnet errors,…) now it is time to focus on the design details 02/12/2015F. Burkart17

18. Summary 02/12/2015F. Burkart18 Arc - choice of magnet aperture is a good starting point, but looks tight study implications of aperture on minimum injection energy further optimization of the filling factor (cell length [aperture!], phase advance per cell [60 o instead of 90 o ?], length of insertions, …) make a second iteration on interconnection length Collimation simulation tools are on good track assess length of the secondary collimator jaws confirm and possibly revise gap size with help of shower simulations attempt to introduce dispersion between primary and secondary collimators RF looks good - the dogleg may need substantial space

19. injection lattice comments: several 100 beam transfers to fill the FCC recommendations: insertions like these should be kept flexible enough to be used as phase trombone station 02/12/2015F. Burkart19

20. extraction lattice comments: this is a challenging system recommendations and questions: does the present optics solution fulfil the basic constraints for an extraction insertion? E.g.  /2 phase advance between MKD and TCDQ  See optics plot later. large  function (>5 km) at the dump  Influence of high beta at the dump is low (see FLUKA studies). 02/12/2015F. Burkart20

21. 02/12/2015F. Burkart21 A.Lechner – FCC dump meeting https://indico.cern.ch/event/446212/

22. overall layout & optimization comments: on good track for the arcs and the two main experimental IRs more work and details needed for other IRs recommendations: continue the excellent work 02/12/2015F. Burkart22

23. 02/12/2015F. Burkart23 Preferred layout

24. Extraction: – Small beta at MKD, big beta at Septum  Asymmetric in optics. – Feasible MKB parameters. – 2.8 km space for passive protection for extraction failures, TCDQ, TCDS,TPSGs  Size / Positions to be defined. – 90 degree phase advance (MKD and TCDQ) – another 180 degrees to the next absorber stage. Dump: – Protection devices. –  of a few km. – Bunch separation: ~ 2 mm – Branch separation: ~ 4 cm Dump cavern: – > 5 m separation to circulating beam. Low radiation to kicker electronics. ?? 02/12/2015F. Burkart24 What influences FCC extraction settings?

25. Dump block considerations: R=1 m Shielding: ~ 3 m (doubled from LHC) Air / crane / catwalk / etc.: ~ 3 m > 5 m wall between cavern and arc  Distance between middle of dump block / circulating beam: >13 m  Asymmetric dump block cavern? To be studied by CE. 02/12/2015F. Burkart25 Dump considerations

26. 02/12/2015F. Burkart26 2.5 km MKDv MSEh MKB 4.2 km 2.3 km Not to scale Extraction failure absorbers / TCDQ Extraction with bend Bend into extra tunnel solution: + fast separation + no radiation to MKB electronics -~ 2.5 km extra tunnel per beam -100m 16T bends in the dump line. -Bend protection needed. -Challenging MKB parameters. 90degree Separation with MSE and bend. 14m separation after 1.5 km but MKB would need 95 Tm.

27. 02/12/2015F. Burkart27 w.o. bend: + only 0.8 km extra tunnel per beam + relaxed MKB settings -“slow” separation -Radiation to MKB electronics? Shielding needed? 0.8 km MKDv MSEh MKB 4.2 km 3.15 km Extraction failure absorbers / TCDQ arc Separation with septum and arc bending (14 m). Not to scale “standard” extraction

28. 02/12/2015F. Burkart28 0.8 km MKDv MSEh MKB 4.2 km arc 4.8 m MSEv Dump line under arc with MSEv. Dump cavern under arc with MSEh. Difficult tunnel geometry (?) at the end of the ESS, to be checked with CE. Not to scale Extraction of both beams MKDh MKB

29. 02/12/2015F. Burkart29 MKB MKDv MSEh MKDv + only 0.8 km extra tunnel per beam + no bend in the dump line + relaxed MKB settings + symmetric systems -slow separation -Radiation to MKB electronics? pipe assembly – X pipe triple aperture quad Not to scale Extraction of both beams to the outside

30. Fixed dilution frequency: f = 50.9 kHz Maximum amplitude at the dump block: 80 cm Bunch separation > 1.8 mm Branch separation: 4 cm Max deflection: 0.32 mrad / 0.254 mrad B.dl = 53 Tm (2.5 km DL) / 42 Tm Alternative with frequency change: f = 20.4 kHz – 42.9 kHz Max amplitude = 0.59 m Bunch separation = 1.9 mm constant Branch separation = 4 cm Max deflection = 0.24 mrad / 0.19mrad Bdl = 39 Tm (2.5 km DL) / 31.7 Tm Energy deposition studies by FLUKA (A.Lechner & P. Garcia) Max. temperature below ~ 1500 °C. Dilution pattern was evaluated as a function of dilution kicker magnet MKB parameters and energy deposition on the TDE. 02/12/2015F. Burkart30 with 3.15 km lever arm Influence on MKB parameters

31. 02/12/2015F. Burkart31 3.1m 4.8m Beam pipes (1/2)

32. 02/12/2015F. Burkart32 14m 2.5m 4.8m 14m Beam pipes (2/2) 0.6m

33. 02/12/2015F. Burkart33 Optics for the ESS Courtesy: L. Stoel

34. 02/12/2015F. Burkart34 Optics for extraction Courtesy: L. Stoel 93.6deg MKD MSE TCDQ

35. 02/12/2015F. Burkart35 MKBh ~ 45 modules MKBv ~ 110 modules Not to scale Quad in the dump line Help the dilution kickers. Reduce aperture in the MKBv. Quad parameters: 70 mm diameter aperture g = 280 T/m L = 6.2m Reduce aperture by a factor 2. Schematic apertures 95m 2.5cm 80cm w.o. Quad w. Quad

36. – 1 sigma oscillation  sweep. – Beam pipe at dump with > 80 cm radius. – X – chamber and beam separation of a few sigma – vacuum issues? – New septum concept. See Dani’s talk. – Optics, beamsizes and positions for absorbers for extraction failures. See Linda’s talk next meeting. – Dump cavern size. – Beam dump window. – Stable field time of MSE in case of a failure. – Absorber requirements: Prepare table with beam parameters, bunch separation and probability for failure cases for TCDS, TCDQ, etc. for FLUKA team. – Impact of Quad on MKB parameters. 02/12/2015F. Burkart36 Comments / to be studied:

37. Thank you for your attention! 02/12/2015F. Burkart37