H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013 Low Emittance Rings...
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Transcript of H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013 Low Emittance Rings...
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013
Low Emittance Rings Workshop, Oxford, UKJuly 8, 2013
ALS Brightness Upgrade & Future Plan
H. Tarawneh, C. Steier, A. Madur, D. RobinLawrence Berkeley National Laboratory
B. Bailey, A. Biocca, A. Black, K. Berg, D. Colomb, N. Li, S Marks, H. Nishimura, E. Norum, C. Pappas, G. Portmann, S. Prestemon, A. Rawlins, D. Robin, S. Rossi, F. Sannibale, T. Scarvie, R. Schlueter, C. Sun, W. Wan, E. Williams.
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013
Outline
• Introduction - ALS Upgrades• Brightness Upgrade
– Lattice Choice– Magnet Design– Installation/Commissioning
• Future directions (ALS-II) - Pre-conceptual: Lattice, Magnets, Injection.• Summary
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013
Brightness Upgrade Scope:
Replacement of the current 46 dipole corrector magnets with 48 combined function magnets (sextupole+HCM+VCM+skew), as well as associated power supplies, controls, interlocks, chamber modifications
Project Schedule:
- Magnet RFP 6/2010- Magnet Installation 10/2012-3/2013 - Migration to low emittance 4/2013
Brightness Upgrade
223 microns (FWHM)
68 microns (FWHM)
Superbend Sourcepoints
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ALS for 20 years has been extremely successful in (soft) x-ray science and newer Facilities could provide potentially better performance and better tools
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013
Why do we add sextupoles?• Reducing the equilibrium emittance is achieved
changing settings of existing quadrupoles • Problem is nonlinear dynamics:
– Sextupoles are too weak to correct chromaticity– Strengthening them would dramatically reduce dynamic
aperture (lifetime, injection efficiency)
• Need additional degrees of freedom– ‘Harmonic’ Sextupoles– ALS lattice already full – needed to replace existing
corrector magnets with multi-magnets
• Possibility for low alpha operation– THz, short bunches
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013
Lattices for ALS upgrade
• There are several possible lattices with ~2 nm rad emittance– 3x smaller than the nominal ALS (~6.3 nmrad)
• Large bx lattice optimizes brightness for the central bends
• Small bx lattice would optimize brightness for the insertion devices further
Current Lattice New Large bx Lattice New Small bx Lattice
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013
Baseline Lattice: Dynamic Aperture• Dynamic aperture is fairly large (larger than current lattice)• Dynamic Momentum Aperture larger• Touschek Lifetime longer than present lattice
• Despite higher density
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013
• Received funding (summer 09)• Comprehensive project review (12/09)• Awarded magnet contract (9/10)• Detailed magnet design review (3/11) • Prototypes of 3 magnet types complete (12/11)• First set of 13 production magnets shipped (4/12)• All magnets received (8/12)• Pre-Installed 13 of 48 sextupoles (1/13)• Remaining magnets and power supplies installed (3/13)• User operation in high brightness mode (2.0 nm emittance) – since (4/13)
Project History
Existing Correctors
Sextupole / Corrector Multimagnets
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013
Top-off calculations with new magnets– Re-analysis necessary, new field profiles– No hardware changes necessary– Wider ranges on topoff interlocks
New fs-slicing bump for new lattice– Using MOGA optimization techniques– Making use of new skew quadrupoles– Also evaluating to switch to horizontal
slicing– Shorter pulses
Supporting analysis of magnet test results – Reducing Commissioning Risk– Hysteresis– Bandwidth– Multipole content
Continuing work to explore low bx lattices
Accelerator Physics Work
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013
Commissioning Results
Measured horizontal photon beam profiles showing the reduction in size and increase in brightness. Above: BL 12.3.2, Below: BL 6.3.1
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• Installation completed on time (Mar/Apr 2013)
• Quick Commissioning Progress– Benefit of pre-installation and
commissioning: orbit feedbacks, detuned upgrade lattice
• Managed to deliver low emittance beam during BLC shifts – and continue into user operations– 3 months ahead of schedule
• Beamlines able to resolve brightness increase
• Reliable operation (no faults due to new lattice or hardware so far)
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013
Beamsize and Beam Dynamics Measurements
-400 -200 0 200 400-100
-50
0
50
100October 24, 2012 October24_2012.opj
z (
m)
y (m)
-400 -200 0 200 400-100
-50
0
50
100spot_size_April16_2013.opjApril 19, 2013
z (
m)
y (m)
10
BL 6.3.1
BL 6.3.1
Confirmed larger dynamic and momentum aperture than high emittance lattice
Beamsize Reduction
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013 11
Brightness Comparison• Comparison to
existing and future light sources (and upgrades)
• Below 1 keV (soft x-ray) ALS is competitive now
• Future: NSLS-II and Max-4 will outperform ALS above 100 eV
Triple Bend Achromat provides very bright bend and Superbend source points from center bend magnets – ALS (2 nm) above NSLS-II 3PW
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013
Looking beyond completed Brightness Upgrade: Assuring world class capabilities for the future
Potential upgrade of ALS ring to diffraction limit
100x increase in brightness
angle
Diffraction Limit upgrade on a 200m circumference ringenables nanoscale microscopes with chemical, magnetic, and electronic resolutionChemical Maps
From 20 nm to 2 nm; from 2D to 3DResolve nano-interfaces in a cathodeObserve the flux in a catalytic network
Electronic MapsnanoARPES of complex phases at 25 nm resolution
Magnetic MapsThermally-driven domain fluctuations imprinted in speckle at nm resolution
new magnets
old magnets
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013
Diffraction Limited Light Sources Recent realization: Still large potential for storage ring
sources• Smaller vacuum+magnet aperture – Multi bend achromat lattices with low
emittance.• Actively pursued: MAX-IV, SIRIUS, ESRF-2, Spring8-2, BAPS, …
Transverse diffraction limited to 2 keV for ALS size is possible – ALS-II
• Using the ALS tunnel to achieve moderate low emittance with moderate cost.
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013
Ongoing Conceptual Machine Design Work
Active Areas of Conceptual Machine Design:• Lattice Optimization• Injection• Collective Effects• Engineering
Considerations (Magnets-DC/pulsed, RF, Vacuum)
• Cost/Schedule
-3 -2 -1 0 1 2 30
0.5
1
1.5
2
2.5
x position [mm] (injection straight)
y po
sitio
n [m
m]
ALS-II lattice frequency map, x = 0cm,
x = 41.1265
-10
-9
-8
-7
-6
-5
-4
-3
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013
Third generation light sources = generous physical apertures (except for IDs which define much smaller admittance) – smaller apertures (factor 3) = much stronger magnets
Nowadays field quality with smaller magnet apertures achievable
MBA lattices provide smaller natural emittances NEG coating - distributed pumping in small
chambers (cheaper)
ALS-II Magnet System
0.78 T & 50 T/mPole Tip Flux: 1.0 T
3000 T/m2 Pole Tip Flux 0.45T
80 T/mPole Tip Flux: 0.9 T
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013
ALS-II Injection Scheme
Brightness evolution
On-axis injection into SR due to small DA Accumulator Ring (AC).
Accumulator ring shares the SR tunnel. AC Lattice Req. (a) DA of ±10 mm. (b) Lifetime ≥2 h. (c) Minimum 4 Straight sections.
Partial Swap-out injection is foreseen Relax requirements on AC ring & pulsed magnets, I=100 mA
𝜖𝑥5𝜖𝑥 𝜖𝑥 Storage
Ring
AccumulatorRing
injecting0.1*Ibeam
BunchTrains
Storedtrain
Storedtrain
Injectedtrain
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H. Tarawneh, C. Steier, A. Madur, D. Robin. L.E. Workshop, July 9, 2013
Summary• Biggest challenge (as well as opportunity) for ALS –
Continuous Renewal– Well balanced plan between machine/facilities upgrades and
beamline/endstation renewal
• Major Machine Renewal example: Brightness upgrade reduced horizontal emittance from 6.3 to 2.0 nm
• Beamlines can resolve brightness increase and realize (full) benefit
• Dramatic performance improvements beyond ALS are possible (at moderate cost) and are now being actively studied.
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