3rd annual eurocircol collaboration meeting · 2018-10-02 · 3rd annual eurocircol collaboration...
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3RD ANNUAL EUROCIRCOL
COLLABORATION MEETING
EuroCirCol-P3-WP1-M1.10
EDMS 1991652
Date: 02/10/2018
Grant Agreement 654305 PUBLIC 1 / 18
Grant Agreement No: 654305
EuroCirCol European Circular Energy-Frontier Collider Study
Horizon 2020 Research and Innovat ion Framework Programme, Research and Innovat ion Act ion
MILESTONE REPORT
3RD ANNUAL EUROCIRCOL
COLLABORATION MEETING
Document identifier: EuroCirCol-P3-WP1-M1.10
EDMS 1991652
Due date: End of Month 39 (September 1, 2018)
Report release date: 02/10/2018
Work package: WP1 Management, coordination and implementation
Lead beneficiary: CERN
Document status: RELEASED (V1.0)
Abstract:
In the scope of the annual meeting report on progress, showstoppers and findings in the form of
selective workshop presentations. Management and governance bodies of the project review the
progress. The approved minutes of the bodies will be made available to the Consortium members and
appropriate news coverage will be performed via the channels identified in the communication plan.
3RD ANNUAL EUROCIRCOL
COLLABORATION MEETING
EuroCirCol-P3-WP1-M1.10
EDMS 1991652
Date: 02/10/2018
Grant Agreement 654305 PUBLIC 2 / 18
Copyright notice:
Copyright © EuroCirCol Consortium, 2015
For more information on EuroCirCol, its partners and contributors please see www.cern.ch/eurocircol.
The European Circular Energy-Frontier Collider Study (EuroCirCol) project has received funding
from the European Union's Horizon 2020 research and innovation programme under grant No
654305. EuroCirCol began in June 2015 and will run for 4 years. The information herein only
reflects the views of its authors and the European Commission is not responsible for any use that
may be made of the information.
Delivery Slip
Name Partner Date
Authored by
Antoine Chancé
Panagiotis Charitos
Rogelio Tomas
Francis Perez
Davide Tommasini
CERN 18/06/18
Edited by Johannes Gutleber
Julie Hadre CERN 28/06/18
Reviewed by Michael Benedikt, Frank Zimmermann CERN 25/09/18
Approved by EuroCirCol Coordination Committee 02/10/18
3RD ANNUAL EUROCIRCOL
COLLABORATION MEETING
EuroCirCol-P3-WP1-M1.10
EDMS 1991652
Date: 02/10/2018
Grant Agreement 654305 PUBLIC 3 / 18
TABLE OF CONTENTS
1. WP1 MANAGEMENT SUMMARY ...................................................................................................................... 4
1.1. 4TH COLLABORATION BOARD .............................................................................................................................. 4 1.2. OUTREACH REPORT ............................................................................................................................................ 5
2. WP2 ARC DESIGN SUMMARY ......................................................................................................................... 11
3. WP3 EXPERIMENTAL INSERTION REGION DESIGN SUMMARY ......................................................... 13
4. WP4 CRYOGENIC BEAM VACUUM SYSTEM SUMMARY ........................................................................ 15
5. WP5 HIGH FIELD MAGNET SUMMARY ....................................................................................................... 16
ANNEX: GLOSSARY .................................................................................................................................................... 18
3RD ANNUAL EUROCIRCOL
COLLABORATION MEETING
EuroCirCol-P3-WP1-M1.10
EDMS 1991652
Date: 02/10/2018
Grant Agreement 654305 PUBLIC 4 / 18
1. WP1 MANAGEMENT SUMMARY
1.1. 4TH COLLABORATION BOARD
1.1.1. Milestones and deliverables
All the milestones and deliverables have been submitted in due time to the EC, except for WP5
milestone on ‘Specifications for conductors and proposed conductor configurations’, which required
further technical discussions during the FCC Week 2018.
One can access the reports on the EuroCirCol website (http://eurocircol.eu/ -> Project -> Dashboard).
Table 1 – Deliverables and Milestones
WP Product Title Due
Date
Lead
beneficiary
1 Milestone 2nd Annual EuroCirCol Collaboration Meeting 01-03-17 CERN
3 Milestone Requirements and constraints of EIR design options on
WP3, WP4, WP5
01-05-17 UOXF
5 Deliverable Identification of preferred dipole design options and cost
estimates
01-08-17 CERN
1 Deliverable Collider complex layout and parameters 01-09-17 CERN
2 Deliverable Requirements and constraints of arc design options on WP3,
WP4, WP5
01-09-17 CEA
1 Milestone Outreach package 01-10-17 CERN
4 Deliverable Measurements of vacuum chamber at light source 01-10-17 ALBA
3 Deliverable Preliminary EIR design baseline 01-11-17 UOXF
4 Deliverable Preliminary beam screen and beam pipe engineering design 01-11-17 ALBA
2 Deliverable Preliminary arc design baseline 01-02-18 CEA
1.1.2. Upcoming events
The Collaboration Board members have been informed about the organization of several events:
The 1st edition of the EASItrain School dedicated to applied superconductivity, at TU Vienna, Austria,
from 3 to 14 September 2018 (https://indico.cern.ch/event/663949/ ) ; A public event in German will
take place on 8 September ‘Forschung? Was geht mich das an?’(http://forschung.web.cern.ch/ ).
The presentation of the FCC Conceptual Design report (EuroCirCol deliverable D1.5) at the University
Paris La Sorbonne on 29 January 2019.
The EuroCirCol industry and outreach event (Milestone M1.12) at Liverpool in February 2019.
The FCC week 2019, which will be combined with the final EuroCirCol Collaboration meeting
(Milestone M1.13), probably in June 2019 in Brussels, Belgium.
1.1.3. Collaboration matters
The WP3 leader Andrei Seryi (JAI UOXF) has taken up a leading position at the Jefferson laboratory
in the US. Consequently, another work package leader had to be found within a short period of time.
The EuroCirCol coordination committee proposed R. Tomas (CERN), presently deputy leader for
WP3 to assume the leading position. The suggestion was rapidly ratified and also confirmed by the
International Collaboration Board. R. Tomas will so take over the role of WP leader as from 01 June
2018. Although the work package lead moved from UOXF to CERN, UOXF remains beneficiary with
key personnel that continues to perform research work in the frame of this project within WP3.
3RD ANNUAL EUROCIRCOL
COLLABORATION MEETING
EuroCirCol-P3-WP1-M1.10
EDMS 1991652
Date: 02/10/2018
Grant Agreement 654305 PUBLIC 5 / 18
1.2. OUTREACH REPORT
1.2.1. Posters
Two posters were produced by the University of Liverpool in collaboration with CERN’s FCC study
office to promote the study among the scientific community. The first one presents the three scenarios
of the FCC, introducing FCC-hh as a discovery machine, FCC-ee as a machine for precision, and FCC-
he as a machine for new opportunities (Figure 1). It also shows the base parameters of each of the
options and their comparison with previous colliders. The second poster addresses the opportunities
opened by the FCC-hh for physics, in particular: testing of the standard model, discovery of new
particles and new symmetries, investigations into dark matter, Higgs physics, heavy ion collisions, and
the unexpected. (Figure 2) The posters are distributed at scientific meetings, particularly during the
FCC weeks.
Figure 1 – FCC scenarios poster Figure 2 – FCC-hh physics opportunities
1.2.2. Article – CERN Courier
An extensive report of the FCC week 2018 was published in June’s issue of the CERN Courier entitled
“CERN’s Thinks Bigger”. (Figure 3) It should be mentioned that in the same issue there was also an
article on China’s future colliders “China’s bid for a circular electron-positron collider”.
Figure 3 – Extract from CERN courier article
A summary of the FCC week 2018 was also published in CERN’s website, in CERN’s Bulletin and in
the EPS newsletter.
The event has also been covered in major Dutch newspapers, including NRC and Volkskrant.
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COLLABORATION MEETING
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Date: 02/10/2018
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1.2.3. Public event
Panel discussion took place on Tuesday, April 10, 2018 at 19:00, Beurs van Berlage, Amsterdam.
Representatives from funding agencies and research centres discussed about the big open questions in
modern physics and the latest developments from the Higgs discovery to gravitational waves. Speakers
also referred to future large-scale research infrastructures that will shed more light on these questions.
There were three main presentations:
Prof. Dr. Jo Van den Brand, Simone Raatz, VU University Amsterdam and Nikhef, “Had Einstein
gelijk? Zwaartekrachtsgolven van botsende zwarte gaten en neutronensterren”.
Prof. Dr. Ivo van Vulpen, University of Amsterdam and Nikhef, “De open mysteries in de
deeltjesfysica na de ontdekking van het higgsdeeltje”.
Prof. Dr. Stan Bentvelsen, Director General of Nikhef, “Inleiding: Het universum van deeltjes”
Figure 4 – Public event at FCC Week 2018
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COLLABORATION MEETING
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EDMS 1991652
Date: 02/10/2018
Grant Agreement 654305 PUBLIC 7 / 18
1.2.4. Innovation awards
The third edition of the FCC Innovation Award, took place during the FCC week 2018 sponsored by
IEEE Council for Superconductivity and one of the FCC collaboration industrial partners, Carbolite
Gero. The award reflects the high-quality work of young researchers towards technological
advancements that guarantee the feasibility of a future high-performance high energy collider.
The FCC innovation awards acknowledge student’s achievements but also ensure more opportunities
for young members of the FCC collaboration to network, to share results and experiences and be part
of the international legacy of expertise in our field. The participation of young researchers in the life
of the FCC collaboration is key for the realization of a new large-scale research infrastructure.
Figure 5 – FCC innovation award winners
1.2.5. Regular coverage of the FCC week 2018
Storify was used again as the main blogging platform for covering this year’s annual meeting. 32
stories were published during the 5 days of the conference – a significant rise compared to the previous
FCC week (26 stories).
On Twitter we run 42 tweets – on a daily rate of 7 tweets while we increase the followers of the FCC
study from 1220 to 1712 while we reached a total of 55.000 impressions.
Figure 6 - Average daily reach on FB during the FCC week. A reach of 7000 people per day while on the 11th the impact
of paid campaigns is clearly indicated (yellow area)
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COLLABORATION MEETING
EuroCirCol-P3-WP1-M1.10
EDMS 1991652
Date: 02/10/2018
Grant Agreement 654305 PUBLIC 8 / 18
Figure 7 - Top tweets made during the FCC week 2018 (all organic reach - no promotional campaigns)
On FB we posted about 40 posts reaching about 36000 people and having 14.301 posts engagement.
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COLLABORATION MEETING
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Date: 02/10/2018
Grant Agreement 654305 PUBLIC 9 / 18
Figure 8 - The curve shows the total reach of FB posts during the FCC week 2018. Different colours indicate where
people read and interacted with the posts. Most of them in their newsfeed (light blue) and a significant number directly
by visiting FCC study FB page (dark blue)
Moreover, during the FCC week 2018 we noticed a good overlap between organic and paid reach
(following our decision not to spend any budget as a training test of FB’s algorithm for the FCC page).
Figure 9 - Total paid (dark yellow) vs. organic (light yellow) reach of FB posts during the FCC week 2018
3RD ANNUAL EUROCIRCOL
COLLABORATION MEETING
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EDMS 1991652
Date: 02/10/2018
Grant Agreement 654305 PUBLIC 10 / 18
Finally, for the first time we tried to increase our activity on LinkedIn where we published 8 stories
during the FCC week all performing very well (average readership: 1200, average number of likes:
25).
Figure 10 – Some EuroCirCol members at FCC Week 2018 (Photography: Elodie Burrillon, HUCOPIX)
3RD ANNUAL EUROCIRCOL
COLLABORATION MEETING
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Date: 02/10/2018
Grant Agreement 654305 PUBLIC 11 / 18
2. WP2 ARC DESIGN SUMMARY
The design, operational considerations (including heavy ion), beam performances, beam stability and
the injector chain of the FCC-hh machine have been shown in 7 sessions with many talks and posters.
The parameters of the 99.75-kilometer-long FCC-hh machine have been given. A draft of the concise
CDR exists. Some improvements are still required but the writing of the CDR is under good tracks.
The efforts will be focused on ultimate parameters. The comprehensive CDR has started.
Different schemes for the injection to FCC-hh have been addressed. Pros and cons of each scheme
have been listed. Currently, dynamic aperture studies exclude injection from superconducting SPS.
New layout of transfer lines is done with protection considerations. The layout of the FCC-hh machine
has a bit changed since FCC week 2017: new high luminosity experimental insertions (L*=40 m and
1.4-kilomer-long), two other experiments combined with injection, shorter short arcs (site
requirements).
The arc cell design (Task 2.2) has been updated after iteration with the magnet team (WP5). The length
estimates are improved. The octupoles are integrated to the arc lattice. The strategy is now to shorten
dipoles to preserve cell length if more space is required for correctors or quadrupole. Full integrated
lattice exists. Specifications for magnets are almost complete. The aperture model has been updated
according to the beam screen progress within WP4. The bottleneck of aperture is at injection in the
dispersion suppressors: optimization of optics and refining aperture requirements should be performed.
An alternative 60° FODO lattice is under study: the main concern is the aperture reduction. Alignment
tolerances for the main magnet of the arcs have been agreed with alignment group. Orbit NbTi
correctors enable to keep the residual orbit and angle compatible with the synchrotron radiation
evacuation. Dedicated beta-beating, dispersion and coupling correction schemes and the full
integration of orbit correction inside experimental region are to be further studied.
A new extraction section is available and should be integrated to the full lattice soon. Main changes
are 150 extraction kickers (against 300 in 2017), larger beam size at protection absorber, and SuShi
septa instead of superferric Lambertson septa. The dump line has been updated. The dilution system
has been modified: a constant frequency is now used (instead of modulated frequency like in 2017). A
new sweep pattern has been developed, which reduces the load on the dump. Required dilution kickers
are still challenging. Some directions to reduce the requirements will be explored. Studies show that
dump functionality is not compromised in case of asynchronous dump.
Dynamic aperture (DA) studies (Task 2.3) show that, if the systematic b3 component of main dipole
is corrected by the sextupole correctors MCS (feasible in NbTi technology), the DA is above the target
value of 12 σ at injection energy of 3.3 TeV. To limit β-beating, the maximum allowed MCS alignment
error should be less than 0.1 mm or the systematic dipole sextupole component should be reduced. The
DA can dramatically decrease when a wrong phase advance between opposite points in the ring is
combined with a set of field errors in different magnets. DA study at collision without beam-beam has
been expanded to include further errors. Thanks to phase scan optimization, almost all studies show
good results, even without non-linear correctors. The compatibility of the phase advance between
collision points should be checked with beam-beam studies within WP3. The phase advance should be
optimized for different other stages of the operation cycle.
Status of the single beam instabilities has been shown (Task 2.4). A distribution of impedance sources
for different instabilities has been made. The beam screen related impedance dominates coupled-bunch
instability. The impedance sources coming from the different beam screen elements have also been
detailed. Resistive wall becomes problematic if aperture is reduced to 12.2 mm. Electron cloud surface
treatment is acceptable if amorphous carbon or TiN coating is used. Measurements at FRESCA will
3RD ANNUAL EUROCIRCOL
COLLABORATION MEETING
EuroCirCol-P3-WP1-M1.10
EDMS 1991652
Date: 02/10/2018
Grant Agreement 654305 PUBLIC 12 / 18
determine if laser treatment is acceptable. Contributions from pumping holes and interconnects are
acceptable. The feedback system, scaled from LHC, is a solid baseline system to damp instabilities.
Simulations show that other operation schemes are feasible (like 5 ns spacing). Progress in simulation
codes will enable to go further in the feedback study. To have more experimental data would be much
appreciated for validation and verification of the models. Feedback will damp the mode m=0 whereas
octupoles will be used to damp the mode m=1. A trade-off is to be found between positive impact of
negative octupole polarity when at flat top, and positive polarity when in collision, because of long-
range beam-beam effects in an electron lens as an alternative for Landau damping is to be studied.
The status of electron cloud studies has been presented (Task 2.5). The effect of beam screen geometry
(from WP4) on electron cloud build-up has been evaluated. The large slit increases multipacting
threshold in drifts. With full chamber and updated parameters, an amorphous carbon coating or surface
laser treatment should be sufficient to suppress build-up for the 25 ns beam. For the alternative bunch
spacing, stability asks for a challenging secondary electron yield (SEY) of 1 in quadrupoles and
possibly coating in field free regions. Estimated photoelectron fluxes are within stability limits.
Photoelectrons from saw-tooth increase density in drifts. The expected flux is to be confirmed with
WP4. Studies have been performed to get electron cloud scaling rules from LHC to FCC. The
conclusion is that SEY threshold depends a lot on the chosen model. Times are mature to use measured
data to tune simulations and refine models.
Considerations about collimation (design, efficiency, or machine protection) have been addressed
(Task 2.6). The next steps for the momentum collimation are to optimize the placement of secondary
collimators and to study the aperture, cleaning performance, and power deposition. A new MARS -
MAD-X/PTC interface has been recently completed. An alternative lattice has also been developed.
The betatron collimation section keeps the layout, design and material of HL-LHC collimators.
Collimators with highest loads are now made of CFC. The energy deposition into the collimators and
the loss distribution into the FCC-hh machine have been calculated. Power on the most loaded primary
collimator has been reduced by halving the primaries’ active length as well as removing the skew
primary. Secondary collimator jaws have been thickened to decrease the power load. Collimation
efficiency has been evaluated. Currently, cleaning at top energy is mostly good for both planes. At
injection, cleaning is less efficient but beam energy is lower too: injection quench limits will determine
if the current design is acceptable. Collimation efficiency has been addressed also in case of failure of
the extraction kicker or collimator imperfections. The misalignment impact is not negligible on global
cold losses. More imperfections should be studied in the future. Cleaning the halos with electron lens
should be developed.
3RD ANNUAL EUROCIRCOL
COLLABORATION MEETING
EuroCirCol-P3-WP1-M1.10
EDMS 1991652
Date: 02/10/2018
Grant Agreement 654305 PUBLIC 13 / 18
3. WP3 EXPERIMENTAL INSERTION REGION DESIGN SUMMARY
The work related to the experimental insertion region design has been reviewed in the morning session
on Tuesday April 10 as well as the collective effect session on Thursday afternoon.
The changes made to the interaction region lattice since the FCC week 2017 were presented. This
includes an L* shortened to 40 m as well as triplet magnets compatible with 15 m long cryostats. These
changes allowed to reduce the maximum beta functions in the triplet and to have fully matched optics
within a 1400 m long straight section. The strengths of the separation and recombination dipoles have
been reduced to 2 T allowing the use of normal conducting technology in this highly radiative
environment. Initial studies with crab cavities suggest a crab voltage of less than 18.5 MV is required
for full crabbing even beyond ultimate beta*. Accordingly 20 m of space were reserved for crab
cavities.
In case operation with crab cavities proves to be impossible, an alternative triplet has been developed.
It features flat beams thereby reducing the required crossing angle. The beat functions at the IP are
0.15 x 1.2 m. This setup reduces the pile-up by 30% but also decreases the integrated luminosity by
20%. Studies of the long range beam-beam effect for flat optics are still ongoing.
Dynamic aperture studies at collision energy showed a significant impact of the phase advance
between the main interaction regions on the dynamic aperture. Optimized phase advances improved
the dynamic aperture from 6 sigma to 16 sigma. However, beam-beam studies revealed that these
phase advances led to a lowered dynamic aperture when octupoles are used to compensate beam-beam
effects. In conclusion, a phase optimization for collision needs to include both magnet errors and beam-
beam effects and different phase advances are needed at different stages of the operational cycle.
Furthermore, the beam-beam studies showed the need to increase the crossing angle in order to
guarantee a dynamic aperture larger than the collimator setting even at high chromaticity operational
scenarios. Two beam stability studies concluded that a negative octupole polarity provides a larger
dynamic aperture. However, the octupole strength with negative polarity is not sufficient with high
chromaticity operation, so stronger octupoles or other compensation techniques are required.
Studies of the energy deposition from collision debris were updated to include the separation and
recombination dipoles as well as the TAN. The reduced L* and shortened triplet magnets led to a
decreased quadrupole aperture and possible shielding thickness, increasing the radiation load in the
new lattice. While the peak power density is still below the expected quench limit, the peak dose
increased to 70 MGy at 30 ab^-1 while the operational limit is only 30 MGy. However, these studies
did not include mitigation strategies like crossing polarity and plane alternation as well as the Q1 split,
both of which have been successfully tested in previous lattice versions. The expected dose with these
strategies is below 40 MGy per 30 ab1.
A total power of 45 kW will be collected in the shielding. One of the reviewers raised concern that the
required cooling capillary diameter might become too large to fit inside the triplet shielding. This issue
was discussed with cryogenics experts, leading to the conclusion that at 15 mm thick cooling channel
is required, which does fit inside the 35 mm thick shielding.
Furthermore the study concluded that the separation dipoles, while normal conducting, require
dedicated protection which should be possible with the given magnet design. In summary, from the
energy deposition point of view, operation with ultimate parameters appears to be possible but needs
further studies, including e.g. the increased crossing angle required due to beam-beam effects.
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COLLABORATION MEETING
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EDMS 1991652
Date: 02/10/2018
Grant Agreement 654305 PUBLIC 14 / 18
The detector cross talk studies concluded that elastically scattered protons only lead to a small
emittance growth. Only negligible amounts of inelastically scattered proton reach next IP and
dedicated collimators in the dispersion suppressors can mitigate cold losses. Furthermore, the range
of muons in the bed rock material is not sufficient to reach adjacent detectors, so the detector cross
talk was determined to be negligible.
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4. WP4 CRYOGENIC BEAM VACUUM SYSTEM SUMMARY
During the FCC week 2018 the activities directly related to the WP4–Cryogenic Beam Vacuum System
Conception, of EuroCirCol were discussed in two oral sessions on Tuesday, April 10th, one at 8:30 and
the second one at 10:30, with a total of four oral presentations. In addition, eight posters were displayed
during the poster session.
In addition, a parallel Coordination Meeting of the WP4 team was held on the morning of Thursday,
April 12th, from 8:30 to 12:30.
During the sessions, the progress and status of the different tasks of the WP4 were reviewed, in
summary:
With respect to the Study of beam induced vacuum effects (Task 4.2) a complete simulation of the
vacuum performance of the designed vacuum chamber screen of a complete cell was presented, with
simulations linking the Synrad+ and the Molflow software results, giving a quantification of the
expected profile of the vacuum level along the arcs of FCC-hh. From this simulation, the allowed
averaged particle density of 1015 H2/m3 is achievable with a conditioning time of around three months.
Also, the simulations of the vacuum behavior of the prototypes installed in the KARA have been
compared with the real measurements done which has confirmed the reliability of the computations.
The analysis of Mitigation strategies to reduce the beam induced vacuum effects (Task 4.3) as well as
the Study of the vacuum stability at cryogenic temperatures (Task 4.4), which should give detailed
experimental results to be able to define the final input parameters of the previous described
simulations, are under way and have been presented. After the preparation and calibration of the
experimental setups first results on copper as well as in different laser treated samples have been
shown. Next step, it is to fully characterize the laser treated samples, which is the initial mitigation
method chosen. The production of laser treated samples with different laser parameters, power and
speed, is under way and will continue with characterization in the cryogenic set-ups.
The final Conceptual design for the cryogenic beam vacuum system (Task 4.5) was also presented in
one of the sessions, where an overview was given of the evolution of the design in the last years in
order to comply with all the requirements imposed by vacuum, cryogenics, thermal and mechanical
stress robustness, beam stability and construction feasibility. The final design will incorporate the saw-
tooth profile as the most efficient way to absorb the synchrotron radiation and reduce the secondary
effects. Two prototypes have been constructed and on third one is under way. All of them will be
measured in the KARA setup allowing the characterization of the behavior of the vacuum chamber
screen under real synchrotron irradiation conditions. Also, two new technologies used for the
construction of the prototype, 3D laser printing and plasma cool spray, were presented, with a large
potential to be used in large scale vacuum chamber construction.
Finally, the results of the measurements of two of the prototypes in the test setup at KARA were
presented, work which is part of the Task 4.6: Measurements on the cryogenic beam vacuum system
prototypes. Data of the measurements of photon secondary desorption (PSD), reflectivity, heat load
and photoelectron generation were presented, with relevant conclusions for the design of the final
vacuum screen. The third prototype will be installed in summer and will be measured until the end of
2018.
In conclusion, a full overview of the works performed along last year in the framework of the
EuroCirCol WP4 was presented.
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5. WP5 HIGH FIELD MAGNET SUMMARY
During the FCC week 2018 the activities directly related to the “WP5–High-Field Accelerator Magnet
Design” of EuroCirCol were discussed in one talk at the 08:30 oral session on Tuesday, April 10th,
four talks at the 15:30 oral session of the same day, and three talks at the 08:30 oral session of
Wednesday, April 11th.
During the sessions, the progress and status of the different tasks of the WP5 were reviewed and can
be summarized as follows.
Task 5.1: Work Package Coordination
This is presently focussed in directing the work towards the compilation of the FCC CDR. The status
and plan has been briefly shown in a talk given by D. Tommasini (CERN). At the time of the FCC
week a first version of the magnets chapter of the CDR was already available and was finalized for
review following the outcome of the FCC week.
Task 5.2: Study accelerator dipole magnet design option
Following the positive results of the creative approaches employed in exploring the three EuroCirCol
design options, cosine-theta, block-coils and common-coils, during the EuroCirCol annual meeting of
2017 it was decided to continue to carry on all the three studies, though having chosen the cosinetheta
design as baseline for the FCC.
All the three design options have been presented in three oral talks given by B. Caiffi (INFN),
E. Rochepault (CEA) and F. Toral (CIEMAT).
The progress in the design since the FCC week 2017 has been considerable, for both electromagnetic
and mechanical aspects. It has been shown that all designs seem feasible with a loadline margin of
14% on paper. However for the cosine-theta and the block-coil two issues have been identified: the
presence of an important magnetic cross-talk between the two magnet apertures, creating a b2
component of about 50 units, and a large effect of magnetization currents in the superconductor
creating a large variation of b3 between injection and collision energies. During the meeting a number
of options were discussed to mitigate these effects with a further development of the study.
For the common coil, the main issue concerns a difficulty in designing an adequate mechanical
structure, coming from the complexity and amplitude of the force distribution in this configuration.
Task 5.3: Develop dipole magnet cost model
The activity of this task has been presented by D. Schoerling (CERN). The talk has highlighted the
importance of the cost of the conductor in the total cost of the magnets, recalling that achieving the
target FCC cost for the conductor shall remain a priority.
Task 5.4: Develop Magnet Conceptual Design
The work is being performed in parallel to the finalization of the baseline design option (cosinetheta),
but was not specifically presented at the FCC week 2018 due to lack of time in the program.
Task 5.5: Conductor studies
The work has been presented in an oral talk given by B. Bordini (CERN) focusing on the electro-
mechanical performance of the conductor. It has been shown that the measurements of cables and
wires under transverse load at CERN, Twente and Geneva Universities correlate the reversible
reduction of the critical current to a decrease of the Bc2. At 1.9 K, assuming a Bc2 equal to 28 T, a
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Date: 02/10/2018
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reduction of the Bc2 by 10 % would produce a reduction of the Jc approximately equal to: 20 % at
12 T, 31 % at 16 T , 44 % at 19 T.
Task 5.6: Devise quench protection concept
The work has been presented in an oral talk given by T. Salmi (CERN), summarizing the approaches
and the results of quench protection studies for all the three EuroCirCol design options. It has been
shown that all design options can respect the temperature limit of 350 K in case the coils are
quenched within 40 ms from the initiation of a quench. This condition can be met either with CLIQ,
or with quench heaters, or using both quench protection systems.
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ANNEX: GLOSSARY
SI units and formatting according to standard ISO 80000-1 on quantities and units are used throughout
this document where applicable.
Acronym Definition
CDR Conceptual Design Report
CFC Carbon Fiber Composite
c.m. Centre of Mass
DA Dynamic Aperture
DIS Dispersion suppressor
EIR Experimental Insertion Region
FCC Future Circular Collider
FCC-hh Hadron Collider within the Future Circular Collider study
FCC-ee Lepton Collider within the Future Circular Collider study
FRESCA Test station facility at CERN
FODO Focusing and defocusing quadrupole lenses in alternating order
HE-LHC High Energy - Large Hadron Collider
HL-LHC High Luminosity – Large Hadron Collider
IBS Intra Beam Scattering
IP Interaction Point
IR Interaction Region
KARA Karlsruhe Research Accelerator
LHC Large Hadron Collider
Nb3Sn Niobium-tin, a metallic chemical
Nb-Ti Niobium-titanium, a superconducting alloy
PSD Photo Secondary Desorption
RF Radio Frequency
RMS Root Mean Square
σ RMS size
SEY Secondary Electron Yield
SPS Super Proton Synchrotron
SR Synchrotron Radiation
SSC Superconducting Super Collider