A DDBA lattice upgrade of the A DDBA lattice upgrade of the Diamond ring Diamond ring R. Bartolini, C. Bailey*, M. Cox*, N. Hammond*, R. Holdsworth*, J. Kay*, J. Jones**, E. Longhi*, S. Mhaskar*, T. Pulampong, G. Rehm*, R. Walker* John Adams Insititute and *Diamond Light Source ** ASTeC/Cockcroft Institute 3 rd Low Emittance Ring Workshop Oxford, 8 July 2013
A DDBA lattice upgrade of the Diamond ring. R. Bartolini, C. Bailey*, M. Cox*, N. Hammond*, R. Holdsworth*, J. Kay*, J. Jones**, E. Longhi*, S. Mhaskar*, T. Pulampong, G. Rehm*, R. Walker* John Adams Insititute and *Diamond Light Source ** ASTeC/Cockcroft Institute. - PowerPoint PPT Presentation
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A DDBA lattice upgrade of the Diamond ringA DDBA lattice upgrade of the Diamond ring
R. Bartolini, C. Bailey*, M. Cox*, N. Hammond*, R. Holdsworth*, J. Kay*, J. Jones**, E. Longhi*, S. Mhaskar*, T. Pulampong, G.
Rehm*, R. Walker*
John Adams Insitituteand
*Diamond Light Source** ASTeC/Cockcroft Institute
3rd Low Emittance Ring WorkshopOxford, 8 July 2013
OutlineOutline
• Diamond upgrade plansMBAs options consideredTools used for optimisationDDBA lattice and its evolution
• Cell2 modification for VMX beamlineAP and ID performanceDesign issues targeting VMX
• Technical subsystems (requirements, challenges and WIP)magnets (see C. Bailey’s talk on Tuesday)engineering integration (see N. Hammond’s talk on Wednesday)vacuum, RF, diagnostics, …
• Future work
3rd Low Emittance Ring WorkshopOxford, 8 July 2013
Emittance in 3Emittance in 3rdrd GLS, DR and B-factories GLS, DR and B-factories
Transverse coherence requires small emittanceDiffraction limit at 0.1 nm requires 8 pm
4
~ 2013
'yy'xx24
fluxbrilliance
2ph
2exx ,
2ph
2exx ',''
2xxxx )D(
2xxxx D )'('
4
Luph
uph L
'
?
MAX IV 7BA 3 GeV 320 pm 500 mA SS length 5m DA 7mm w/errors
Sirius 5BA w/superbend
3 280 500 5m & 6m 5 mm w/errors
Spring-8 6BA 6 67.5 300 4.5m & 27m 3 mm w/errors
APS 7BA 6 147 100
Pep-X 7BA 4.5 11 200 5 m 10 mm w/errors
ESRF Phase II
7BA 6 130 200 5m 10 mm
SOLEIL QBA w/longit.. gradient dipole
2.75 980 (220)
500 Robins. Wiggler + beam adapter
Diamond mod. 4BA, 5BA, 7BA
3 45-300 300 5m & 7 m 2 mm
ALS 5BA - 7BA 2 50-100 500 5 m 2-3 mm
BAPS 7BA-15BA 5 50 150 10m & 7m 10 mm w/errors
tUSR 7BA 9 3 100 TEV tunnel 0.8 mm
Survey of low emittance lattices (Beijing Nov. 2012)
Lattice design at DiamondLattice design at Diamond
• Initial criteria
Reuse tunnel and beamlinesReuse as much hardware as possiblePhased installation (avoid long shutdown)
• Evolution of MBA design
Initial low emittance lattice design used standard MBA cells M = 7, 6, 5 and 4
It transpired that a 4BA cell can be modified to introduce an additional straight in the middle of an arc (a generalisation of SOLEIL’s approach*)
while keeping the dispersion small and the emittance small
3rd Low Emittance Ring WorkshopOxford, 8 July 2013
Lattice design at DiamondLattice design at Diamond
Early studies with MBAs
3rd Low Emittance Ring WorkshopOxford, 8 July 2013
Original DBA
0 5 10 15 20X[m]
-8
-6
-4
-2
0
2
4
6
8
10
Y[m]
5BA
5BA and 7BA fitting Diamond cell length5BA and 7BA fitting Diamond cell length
Original DBA
0 5 10 15 20X[m]
-8
-6
-4
-2
0
2
4
6
8
10
Y[m]
7BA
5BA optimisation5BA optimisation
Driving term compensation after 4 cells
Fourth order and detuning terms much harder to compensate
MOGA sumDiff + sumRDTs using harmonic sextupoles; chromaticity (2,2)
DA optimisationDA optimisation
3rd Low Emittance Ring WorkshopOxford, 8 July 2013
The optimisation of the DA and lifetime is an iterative process that involves
Linear optic matching and working point selectionRDT analysis, FM and detuning curve checkMOGA
DA achieved (WIP) 4BA DA 5 mm5BA DA 3.5 mm7BA DA 1 mm
IBS emittance blow-up as a function of stored current coupling 10% 900 bunches – computed with elegant
4BA H emittance
IBS emittance increaseIBS emittance increase
3rd Low Emittance Ring WorkshopOxford, 8 July 2013
3rd Low Emittance Ring WorkshopOxford, 8 July 2013
(half) DDBA cell(half) DDBA cell
3.4m mid-cell straight
55 T/m 15 cm
65 T/m 20 cm
-14 T/m 66cm
-15 T/m 96cm
55 T/m 15 cm50 T/m2
20 cm
Challenging magnets which require a small bore radius (15mm)but no showstoppers !
Other projects have much more agressive requirements
Even if the minimisation of the emittance is not a primary target, the tight control of dispersion and beta functions requires very strong quads
3rd Low Emittance Ring WorkshopOxford, 8 July 2013
Magnets for USR (Beijing November 2012)Magnets for USR (Beijing November 2012)
Diffraction limited emittance requires magnets with unprecedented strength in storage ring. High gradient and high precision required
quadrupole gradient MAX IV has 40.0 T/mESRF 100 T/mSpring8-II 80 T/mBAPS 50 T/m USR 90 T/m
quadrupoles in dipoles MAX IV has 9 T/m ESRF 30 T/m
sextupoles MAX IV has 4000 T/m2ESRF- USR 7000 T/m2
Spring-8 II 13000 T/m2)
BAPS 7500 T/m2
space between magnets (hard edge) 10 cm MAX IV has 2.5 cmApertures = 20-26 mm diameter in arcs MAX IV inner diam. 22 mm
3rd Low Emittance Ring WorkshopOxford, 8 July 2013
Ring optics with and without two DDBA cellsRing optics with and without two DDBA cells
3rd Low Emittance Ring WorkshopOxford, 8 July 2013
Parameters
Emittance [m-rad]
Tune x Tune y ChromaticityLifetime [h]
2.55e-9 29.1813.30
2,28.2 (23.h)
Two DDBAs: dynamic aperture and lifetime with Two DDBAs: dynamic aperture and lifetime with MOGAMOGA
3rd Low Emittance Ring WorkshopOxford, 8 July 2013
ConclusionsConclusions
Diamond is investigating a full ring upgrade for Diamond – II
Various MBA options are under analysis. We concentrated on a modified 4BA (DDBA) that doubles the capacity and reduces the emittance by a factor 10.
Feasibility studies for the cell2 upgrade to a DDBA cell are promising
• AP-wise the design is feasible• Many technical subsystems prove challenging but no showstoppers have been identified (magnets, vacuum, engineering integration, diagnostics,. …)• Benefit for ID performance are noticeable
Underpins R&D for the full upgrade. Significant further detailed design is needed, as well as R&D for vacuum vessel fabrication and NEG coating
Costing exercise is underway but the project has been fully supported from a technical point of view.
3rd Low Emittance Ring WorkshopOxford, 8 July 2013