review of FCC-hh optics & beam

dynamicsIPNO, 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 65430502/12/2015 F. Burkart 1

review agendaTime (19.11) length title speaker14:00 Welcome and review goals Michael Benedikt14:00-14:20 20 min. Arc lattice, lattice integration Antoine Chance14:20-14:40 20 min. IR lattice Andrei Seryi14:40-14:50 10 min. Minimum separation of detectors Rob Appleby14:50-15:05 15 min. Collimation system requirements Stefano Redaelli15:05-15:20 15 min. Betatron& momentum coll. lattices Antoine Lachaize15:20-15:40 20 min. Collimation tracking & evaluation James Molson15:40-16:10 30 min. Discussion16:10-16:30 20 min. Coffee break16:30-16:45 15 min. Injection lattice section Florian Burkart16:45-16:55 10 min. Integration of RF Bernhard Holzer 16:55-17:10 15 min. Extraction/dump lattice section Florian Burkart17:10-17:30 20 min. Errors,tolerances,corrections DA Barbara Dalena17:30-18:00 30 min. Overall layout & optimization Daniel Schulte18:00-18:30 30 min. Discussion

Time (20.11) length title Speaker09:00-11:00 120 min. Executive session (closed) reviewers

Additional invitees: WP2 and WP3 participants, R. Aleksan (ECB chair)02/12/2015 F. Burkart 2

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

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Review of FCC-hh optics & beam dynamics

Extraction lattice section

19. / 20. November 2015

Input fromM. Barnes, W.Bartmann, M.Benedikt, F.Burkart, B.Goddard,

W.Herr, T. Kramer, A. Lechner, D. Schulte, L.Stoel

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• Beam extraction concept and optics.• Dilution kicker requirements.• Beam dump line geometry.• Conclusions

Outline

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Extraction straight options

Too tight.R2E.

MKB parameters.

Too tight.R2E.

MKB parameters.

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• “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

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Enlarged quadrupole

Triple chamber quadrupole?

MKBH MKBVKicker0.13mrad

Septum1.7 mrad, 1.42 T

HW parameters

LHC scaled Kicker Septum

B.dl T.m 2 - 22 19 - 284

Available system length m 100 200

Rise time us 3 -

Flat top length us >340

GFR h/v mm 18/18 18/18

Aim for 1 us due to absorber limits

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• 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

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Beam dump line geometry

1.4 km dump insertion 2.8 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).

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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

RF1.4 km dump insertion2.6 km passive protection

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“Baseline 2”

Hydrodynamic tunneling simulation benchmark with HiRadMat experiment and simulations with FCC beam parameters

12

Beam dump considerations

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90.400 K

120.000 K

Beam dump considerationsCopper 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!

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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.

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Dilution kicker system

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• 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

• “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

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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

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Summary

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• 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 [60o instead of 90o?], 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

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

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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.• p/2 phase advance between MKD and TCDQ See optics plot later.• large b function (>5 km) at the dump Influence of high beta at the dump is low (see FLUKA studies).

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A.Lechner – FCC dump meetinghttps://indico.cern.ch/event/446212/

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

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Preferred layout

• 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.– b 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.• ??

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What influences FCC extraction settings?

• Dump block considerations:• R=1 m• Shielding: ~ 3 m (doubled from LHC)• Air / crane / catwalk / etc.: ~ 3 m • > 5 m wall between cavern and arcDistance between middle of dump block / circulating beam: >13 m

Asymmetric dump block cavern? To be studied by CE.

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Dump considerations

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2.5 km

MKDvMSEhMKB

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.

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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

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0.8 km

MKDv MSEh MKB

4.2 km

arcarc

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

MKDhMKB

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MKB MKB

MKDvMSEh

MSEhMKDv

+ 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

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.

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with 3.15 km lever arm

Influence on MKB parameters

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3.1m 4.8m4.8m

Beam pipes (1/2)

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14m

2.5m 4.8m4.8m

14m

Beam pipes (2/2)

0.6m

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Optics for the ESS

Courtesy: L. Stoel

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Optics for extraction

Courtesy: L. Stoel

93.6deg

MKDMSE

TCDQ

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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

– 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.

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Comments / to be studied:

Thank you for your attention!

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