PowerPoint PresentationThis project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No 730871.
Highlights from 8th Low-Emittance Ring
Workshop
1
2 FCC-ee Optics Design Meeting - 06/11/2020
https://agenda.infn.it/event/20813/
3 R. Bartolini, 8th Low emittance ring workshop, Frascati, 30/10/2020
1th Low Emittance Rings Workshop, 12-15 January 2010 CERN – participants 70 https://ler2010.web.cern.ch/ 2th Low Emittance Rings Workshop, 3-5 October 2011 Heraklion, Crete https://lowering2011.web.cern.ch/
3th Low Emittance Rings Workshop 8-10 July 2013 Oxford University https://indico.cern.ch/event/247069/overview (EuCARD-2) – participants 80 4th Low Emittance Rings Workshop, 17-19 September 2014, INFN-LNF Frascati https://agenda.infn.it/event/7766/ (EuCARD-2) – participants 67 5th Low Emittance Rings Workshop, 15-17 September 2015 ESRF, Grenoble https://indico.cern.ch/event/395487/overview (EuCARD-2) 6th Low Emittance Rings Workshop, 26-28 October 2016 • Synchrotron SOLEIL https://www.synchrotron-soleil.fr/en/events/low-emittance-rings-workshop-2016 (EuCARD-2) 7th LER Workshop, 15-17 January 2018 CERN (ARIES) https://indico.cern.ch/event/671745/ 8th LER Workshop 26-30 October 2020 INFN-LNF Frascati (held remotely) (ARIES) https://agenda.infn.it/event/20813/overview – participants 160
Courtesy S. Guiducci
4 R. Bartolini, 8th Low emittance ring workshop, Frascati, 30/10/2020
Mission of the network and workshops
Fostering networking activities, exchange of ideas and staff in the accelerator community involved in design, construction and operation of
ultra-low emittance rings (light sources, HEP: damping rings and colliders)
via
Student support (and student prizes) Supporting staff for joint experiments engagement with industrial partners
Topical workshop
5 R. Bartolini, 8th Low emittance ring workshop, Frascati, 30/10/2020
Many topical workshops:
Low emittance ring technology ALERT 14 Valencia ALERT 16 Trieste ALERT 19 Ioannina
Collective effects TWIICE 2014 Soleil TWIICE 2016 Diamond
Diagnostics DULER Diamond 2018
Commissioning KIT 2019
6 R. Bartolini, 8th Low emittance ring workshop, Frascati, 26/10/2020
Statistics
• 160 registered participants
• Low Emittance Rings Design, Commissioning and Operation
• Collective effects and feedbacks
• Injection systems
Sirius Progress - Liu Lin
9 FCC-ee Optics Design Meeting - 06/11/2020
• Off-axis injection in horizontal plane using Non-Linear Kicker (NLK) for beam accumulation (2 Hz)
• Measured emittance 400 pm
• Vacuum System(fully in-house NEG-coated chambers), pressure target to be reached before expected
• Commissioning started end 2019 slow but steady progress (pandemic), reach (phase 1) design parameters by end 2021.
Overview of Hefei Advanced Light Facility project
- Faya Wang
• Full energy linac followed by a 2.2
GeV storage ring
• Injection with a fast non-linear
kicker (reduce DA requirements)
effect reduction
source SKIF – Evgeni Levichev
11 FCC-ee Optics Design Meeting - 06/11/2020
• Design of the new Novosibirsk 4th generation light source SKIF provides natural emittance 73 pm for 3 GeV beam energy and 476 m circumference
• Two sextupole families provide DA and momentum acceptance sufficient for good beam lifetime and traditional injection.
• For all major systems the R&D is completed and design stage is started.
PETRA IV Machine Upgrade – Riccardo Bartolini
12 FCC-ee Optics Design Meeting - 06/11/2020
• Achieving 20 pm at 6 GeV with
scaled version of the ESRF-EBS
lattice
project at DESY
and define protype programme
SLS2 upgrade – Masamitsu Aiba
• Injection scheme
• Small horizontal emittance, 2~3 nm, from booster (emittance exchange)
• Aperture sharing with short pulse kicker ~20 ns, (affecting only a few bunches)
• Future upgrade to very fast kicker, 2~4 ns, disturbing only 1 bunch
Parameters Values Remark
Circumference 288 m Total absolute bending angle of 430 degree with RB
Beam energy 2.7 GeV SLS operation at 2.4 GeV
Nominal beam current 400 mA As of SLS
Betatron tunes (H/V) 39.35/19.22 Uncorrected chromaticity -99.0 / -33.4
Momentum compaction factor 1.04x10-4 Negative alpha lattice abondoned
Natural energy spread 1146 ppm 1160 ppm with IBS, 1040 ppm with all IDs
Natural emittance 157 pm 161 pm with IBS, 135 pm with all IDs
Damping partition (H/V/L) 1.82 / 1.0 / 1.18
Damping time 4.1 / 7.5 / 6.4 ms 3.6 / 5.8 / 4.3 ms with all IDs
Radiation loss per turn 689 keV 900 keV with all IDs
RF frequency 500 MHz Passive 3HC in addition to 500 MHz system
Nominal RF voltage 1.44 MV RF bucket height -6.2/+4.5%, 1.7 MV with all IDs
Beam lifetime 11 hours Ideal lattice with 3HC and 10-9 mbar CO
Number of Superbends 4 To be installed after commissioning
Superbend peak field 5 / 3.5 / 2.1 T 2.1 T bend with P.M., otherwise superconducting
Total length of straight for IDs 50 m
-8 -6 -4 -2 0 2 4
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
x (
Using Complex Bends – Guimei Wang
14 FCC-ee Optics Design Meeting - 06/11/2020
• A bending element consisting of dipole poles, interleaved with strong focusing and defocusing quadrupole poles, QF-D-B-D- QD-D-B-D (CB)
• Integration in the NSLSII lattice for 30-fold emittance reduction
• DA increase with octupoles (3 families)
Challenges and Solutions for the APS-U Design – Michael Borland
15 FCC-ee Optics Design Meeting - 06/11/2020
• 7-bend achromat a la ESRF-EBS
• Reaching ~40 pm emittance @ 6
GeV
• Starting end of 11/2019,
accumulated 200 mA already
schedule!)
EBS commissioning – Pantaleo Raimondi
Elettra 2.0 - Emanuel Karantzoulis
DAFNE status – Antonio De Santis
19 FCC-ee Optics Design Meeting - 06/11/2020
• Crab-Waist collision scheme implemented for the first time with a large detector including a high intensity axial field.
• PM’s reused with new lattice scheme to correct coupling
• The new approach to collision provided a ~60% improvement in terms of Lpeak
• SuperKEKB collider achieved the world's highest luminosity (KEK press release of 26 June 2020)
Collective effects and
Impact of detuning impedance – Elias Metral, Nicolo
Biancacci, Giovanni Rumolo
detuning impedance observed in the
frame of the study of the PS instability
at injection.
“Short-bunch” regime with a
is predicted wrt to the driving
impedance
impedance (confirmed by
the net effect of coupling at higher
intensities and eventually
0.5
1.0
1.5
2.0
κ
upgrade – Alexis Gamelin
• Passive NC HC induces asymmetric
bunch profiles if not at design current
• Passive SC HC always induces
asymmetric bunch profiles
if HC tuned to HC past the minimum
of voltage derivative with time
• AC Robinson instability can limit the
maximum bunch length
severe transient beam loading, which
can be mitigated with different choices
(lower R/Q. higher main cavity
voltage, Shorter gaps, asymmetric
system with dedicated cavity
by harmonic cavities for ALS-U – Marko Venturini
FCC-ee Optics Design Meeting - 06/11/2020 23
Feedback systems for FCCee – Alessandro Drago
24 FCC-ee Optics Design Meeting - 06/11/2020
• Instability growth rates of ~1 turn require strong R&D efforts
• Less critical instability growth rates can be coped by a more moderate R&D program.
• From the ring impedance point of view, it is important to underline that the three feedback design options have different impact.
• The option A requires only one cavity kicker for the longitudinal case and two stripline kickers for the transverse planes (1 H + 1 V).
• Both options B and C need four cavity kickers and eight stripline kickers increasing consequently the ring impedance.
Combined effect of IBS and impedance on the
longitudinal beam dynamics – Alexei Blednyk
25 FCC-ee Optics Design Meeting - 06/11/2020
Vacuum
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Vacuum chamber design and fabrication -
Theo Sinkovit For vendors of storage ring vacuum chambers the future is:
Busy. There is a lot of need coming soon.
Demanding for machining capabilities.
Needs careful planning to accommodate post assembly machining of flanges.
Assembly cycles must be well thought out to enable all the fabrication steps.
Impedance is important for design and fabrication decision making.
Surface engineering must be considered early in design.
There are gaps in our understanding of some engineered surfaces:
Getter films are complex and designers must be informed about limitations for use and for fabrication steps to be realistic.
Copper or conductive films are not well examined for PSD. Or am I not well informed?
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industrial point of view – Tomasso Porcelli
NEG coating is an enabling technology for Low Emittance Ring
Given the chambers complexity of LER, NEG coating presents many challenges in terms of
uniform thickness and composition
Stability of the plasma Deposition in not-cylindrical geometries
SAES is ready to deposit large batches of chambers with diameters down to 6 mm
The NEG deposition process of complex chambers are under refinement
ID=6 mm Average thickness: ~1.3 μm (±38%)
Vacuum considerations for FCCee –
Roberto Kersevan • CAD models of the common-
yoke dipole and quadrupole magnets and SUPERKEKB- type vacuum chambers with integrated SR absorbers pumps
• Reduced photodesorption yield h(mol/ph) achieved via massive NEG-coating of the chambers.
• Experimentally validated the “thin NEG” solution
• Use of lumped absorbers placed at strategic locations to intercept all of the primary SR at IR
30
the SOLEIL upgrade - Vincent Le Roux
Alignment, low emittance
Fast Beam Based Alignment Using AC Corrector
Excitations – Zeus Marti • Using the FOFB hardware,
developed method to
perform quadrupole BBA
and achieving even better
simultaneous analysis of
tilt.
Low emittance tuning for FCCee rings – Tessa Charles
• Studied a wide combination of magnet tolerances for field errors, alignment of individual magnets, girders and BPMs settings
• Developed correction algorithms leading to successful convergence for large majority of applied errors seeds.
• Achieve values of coupling and beam emittance that lie within the requirements
Median y / x = 0.0047 %
ttbar (182.5 GeV) 4IP lattice, after correction strategy:
Fast dynamic aperture optimization with reversal
integration – Yongjun Li • Early chaos indicator using
forward reversal integration
rule out uncompetitive
integration – Yongjun Li • Vertical source size fluctuations show
up as intensity variations at highly
sensitive beamlines
ALS dispersion wave (skew
scanning DWP & various ID
• Resulting NN can give prediction for
DWP required to keep beam size
constant for arbitrary ID
FF
Injection systems
• Extended linear coupling theory
the SR, explaining why there might be
only partial emittance exchange on
coupling resonance.
flat beams
operating in round beam mode is
straight forward for on-axis injection
schemes (swap-out or longitudinal
amplitude dependent tune shift.
including stripline and two
• Measured field homogeneity of
to requirements
Emittance Rings – David Garand
– Ubaldo Irizo
41
• Beam size instrumentation and its stability can become a real challenge to measure beamsizes ~1μm.
• X-ray instrumentation like CRL and monochromators in stable girders can increase the budget for the diagnostics beamlines significantly
• From “parasitic” diagnostics beamlines to “user-type” diagnostics beamlines, combining different techniques to cover different needs (APSU Example)
Diffracted Cherenkov radiation diagnostics –
• directional
beam position (CLEAR)
• Incoherent ChDR: • potential for beam profile,
position
ChDR studies for FCCee – bunch position
Magnets
Daniel Schoerling
44
• 10 year-collaboration between CERN and KIT and with other partners for SC wiggler and undulator magnets
• Built several prototypes and with BINP a full scale Nb-Ti wiggler installed and operated in KARA
• Recently, activities towards HTS undulators and wigglers
• Plan to build in the next year test coils, and two short 5- period prototypes and a 0.5-1 m long prototype (pending resources)
• Part of the HTS magnet development program of CERN and profits from the main line development towards a 20+ T magnet
period length λu / mm
HTS (VR) B / T
13 1.8 2.3 2.3 1.0 1.2 1.67
15 2.3 3.0 2.8 1.5 1.5 1.77
Longitudinal variable bend prototype for the
CLIC damping rings – Manuel Domínguez • Novel longitudinal magnet concept with trapezoidal bending radius, 2.3 T
peak field and ~10 T/m gradient for CLIC DR
• Proved the horizontal emittance reduction to ultra-low levels of i.e. ~60 pm @
2.86 GeV, for the CLIC DR (M. A. Dominguez Martinez et al., IEEE Trans. Appl. Supercond. 28, 1, 2018;
S. Papadopoulou et al, PRAB 22, 091601, 2019)
• First demonstrator already under construction by CIEMAT
• Fabricate a prototype for the ELETTRA upgrade financed by I.FAST
Y. Papaphilippou - LER 2020 45
Magnet Overview
Flux concentration
Dimensions:
Weight: 1.1 T Steel 1010
for ESRF-EBS – Gael Le Bec
46
between magnets
calibration issues
• Large discrepancies between model and real lattice at the restart
• Recovered by inserting cross-talk effects in the model
• No change in lattice performances at the end
A special thank…
to Marica Biagini