1. Layout
Daniel Schulte for the FCC-hh teams
ALBA, November 2016

2. Initial Beam Parameters
Assume round beams
H-V crossing
Use of crab cavities for ultimate parameters
Aim to establish feasibility of ultimate parameters
Consider alternatives for crab cavities
Consider flat beams
FCC-hh Baseline
FCC-hh Ultimate
Luminosity L [1034cm-2s-1] 5 20
Background events/bx
170 (34)
680 (136)
Bunch distance Δt [ns]
25 (5)
Bunch charge N [1011]
1 (0.2)
Fract. of ring filled ηfill [%] 80
Norm. emitt. [mm]
2.2(0.44)
Max ξ for 2 IPs
0.01
(0.02)
0.03
IP beta-function β [m]
1.1
0.3
IP beam size σ [mm]
6.8 (3)
3.5 (1.6)
RMS bunch length σz [cm] 8
Crossing angle [s’] 14
Crab. Cav.
Turn-around time [h] 4
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

3. Layout and Overview, ALBA, November 2016
Luminosity
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

4. FCC-hh Baseline Layout, Rome 2016
Main experiments in A and G
Side experiments in H and F
Injection and RF in B and L
cleanest place
Extraction, betatron- and momentum collimation combined in D and J
could also be extraction in D and all collimation in J
Are allowed to consider merging injection and side experiments
Change from
“Four great places for experiments” to
“Can accommodate two additional experiments with somewhat less favorable conditions”
Note:
1.4km length = sqrt(50/7)*0.5km
Betatron cleaning and extraction are dominated by losses => more space
Currently 18% of tunnel in limestone, 10% under the Jura
Shorten distance A to G
Shorten J and D from 4.2 to 2.8km or 1.4km
Have to distribute functionalities differently
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

5. Layout and Overview, ALBA, November 2016
Tentative New Layout
Main experiments in A and G
Side experiments in B and L, combined with injection
Extraction in D
Betatron cleaning in J
Energy collimation in F
RF and instrumentation in H
Risk in B and L has to be evaluated
Gives room for betatroncleaning and extraction
both are high risk
both might have some potential to be slightly shortened
Clean insertion for RF and instrumentation
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

6. Layout and Overview, ALBA, November 2016
Lattice Design
Full lattice design for the old layout exists
Now are working on new layout
No changes at A and G
Lengths for energy and betatron collimation should allow to use existing designs
Extraction insertion design has been shortened
RF insertion should be straightforward
Main differences are at L and B
Injection in 700m
Experiment in 700m
Or overlapping design (as in LHC)
Integration required
Arcs need to be adjusted
Many conclusions from the old lattice design are still valid
Should be able to fit the optics into the insertions
But quite some work remaining
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

7. Layout and Overview, ALBA, November 2016
Collimation
Have betatron and momentum cleaning designs based on LHC
First evaluation of loss maps
Aperture around the ring studied
impedance is very important
Key issues:
Overall protection is being addressed
Impedance is being studied
Losses in the downstream dispersion suppressor are too high
Are designing dispersion suppressor protection (A. Krainer)
Loss in betatron collimation can be up to 11MW (12 minutes lifetime)
This can make survival of components and protection hard
in LHC 10% of loss goes into one dipole, the same into one protection device
Work only started
May impact collimation system lattice but hopefully not increase length
Claims on large uncertainty of single diffractive process need to be resolved
Alternative/improved optics and technology solutions need to be explored
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

8. Overall Experiment Configuration
Round beams and H-V crossing assumed (A+G)
Assume aggressive tuneshift of 0.03 (total) is viable
need to translate into noise requirements
Side experiments get much less luminosity
should contribute next to nothing to beam-beam tuneshift
Need to study flat beam options
Collision debris from one experiment to the next through short arc could be a problem
Studies indicate that the separation is sufficient
Losses in dispersion suppressors can be an issue
Try to use the same design as for collimation system
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

9. Old FCC Detector (Now Alternative)
Modified from W. Riegler et al.
W. Riedler
Tracking
Ecal
HCAL
Magnets and cryostat
Muons
Hall half length: 35m
L*=45 m
Have iterated on L*
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

10. Layout and Overview, ALBA, November 2016
New FCC Detector
Experiments like to stay at L*=45m to allow for other solutions
But high cost for this
Tracking
Ecal
HCAL
Magnets and cryostat
Muons
No dipole any more
But forward solenoid
Hall half length: 35m
L*=45 m
Detector half length 23.5m
Space to open 11.5m
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

11. Layout and Overview, ALBA, November 2016
Triplet Design
Key issues:
Small betafunction with enough dynamic aperture
Collision debris destroys triplet magnets
Beam stay clear defines aperture of collimation system (and impacts length)
Studied different solutions with L* of 36, 61 and 45m
good optics performance for L*=36m
The new L*=45m triplets offer much larger aperture but currently struggle with dynamic aperture
work on lattice design, codes, specifications for the magnets (field and quality), …
or back-off somewhat
How to best use the aperture?
More shielding to increase triplet lifetime?
Smaller beta-functions to require less beam-beam tuneshift?
Larger aperture to shorten collimation system?
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

12. Injection and Extraction
Extraction insertion and dump line designs exist
Injection insertion concept exists and is being integrated with side experiment
Key injection issue:
A injected or circulating batch can be kicked into the machine
Filling pattern
Key extraction issues:
Dilution/painting of the extracted beam on the dump
Population of extraction gap
Emergency extraction
Studies of losses and robustness are critical
Optimisation of system design
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

13. Magnets and Beamscreen
Different magnet designs are being pursued
All have 16T and aperture of 50mm
Operation temperature fixed at 1.9K
need much less cable
limited increase in cryo plant cost
Beamscreen around 50K
efficient cooling of synchrotron radiation
need 100MW to cool 5MW
Beamscreen design for impedance
Aperture
Coating thickness
Shielding of pumping holes
Other impedances potential drivers at injection
Suppression of electron cloud essential
also avoiding direct photo-production
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

14. Arcs and Integrated Design
Integrated lattice for old baseline existed
Working on it for new layout
16T required to reach 50TeV/beam
Many design details are being worked out
Space for multipoles, …
Correction of dispersion from crossing in experiments …
Dynamic aperture are ongoing
feedback given to magnet team on B3
Tolerance studies are ongoing
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

15. Layout and Overview, ALBA, November 2016
Conclusion
Are preparing to fix the baseline for Berlin
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

16. Layout and Overview, ALBA, November 2016
Reserve
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

17. FCC Study time line towards CDR
2014
2015
2016
2017
2018 Q1 Q2 Q3 Q4
Study plan, scope definition
Explore options
“weak interaction”
conceptual study of baseline “strong interact.”
FCC Week 2015:
work towards baseline
FCC Week 17 & Review Cost model, LHC results  study re-scoping?
FCC Week 2016
Progress review
Elaboration,
consolidation
FCC Week 2018
 contents of CDR
Report
CDR ready
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

18. Layout and Overview, ALBA, November 2016
New Triplet Design
Dynamic aperture with beam-beam
Head-on similar to L*=61m
None with crossing angle
Seem to have a problem with the existing simulation code (SIXTRACK)
EPFL
CERN
Experiment separation
Debris transfer from the experiment
Seems to be OK in the next experiments
But need protection of arcs
UNIMAN
Radiation damage of triplets
Current limit 30MGy
Conclusions for spectrometer and 30ab-1
15mm shielding 150MGy
55mm shielding 30MGy
CERN
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

19. Layout and Overview, ALBA, November 2016
Tentative New Layout
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

20. New Layout Considerations
Combining injection and experiments in L and B
Maybe possible to inject after experiment
Betatron collimation in H
2.8km long
Extraction in F
System length requirement reduced from 3.5km to 2.1km
Energy Collimation in D
1.4km
RF in J
Very clean insertion also for diagnostics
Not liked by civil engineering
D and F have very deep shafts (600m)
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016

21. New Layout Considerations
Reduce the insertions L, B, H and F to 2.1km
Better for civil engineering
Side experiments and injection in B and L
Would likely have to inject before experiments
Extraction in F (appears possible)
Betatron collimation system in H has to be shortened
maybe possible
Energy collimation in D
RF in J
Note: combination of injection and extraction and experiments in D and J not good option due to deep shaft in D
Not clear how much performance improvement 2.1km long injection insertions mean for side experiments
Shorter insertions for the highest risk systems, extraction and betatron collimation
D. Schulte for the FCC-hh team
Layout and Overview, ALBA, November 2016