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Diamond Light Source Status and Diamond Light Source Status and Future ChallangesFuture Challanges
R. BartoliniDiamond Light Source Ltd
and
John Adams InstituteUniversity of Oxford
DL-RAL Joint Accelerator Workshop
20 January 2009
SummarySummary
1) Introduction to Diamond
2) Status of the 3 GeV Storage Ring
Orbit correction; Optics control; IDs; Orbit stability;
3) Latest developments and future challenges
Top-Up operation;
Further ID installation; Customised optics;
Ultra short radiation pulse generation;
DL-RAL Joint Accelerator Workshop
20 January 2009
235 m
100 MeV Linac
3 GeV BoosterC = 158.4 m
3 GeV Storage RingC = 561.6 m
Experimental Hall and Beamlines
235 m
office building
peripheral labs. and
offices
future long beamlines
technical plant
Diamond LayoutDiamond Layout
Milestones and key factsMilestones and key facts
First LINAC beam (100 MeV)
First turn in booster
First turn in Storage ring
Beamline commissioning start
First users
300 mA
January 2009: 13 IDs operational
2007: 3120 h operation (uptime for users 92.4%)
2008: 4080 h operation (uptime for users 94.9%)
2009: 4656 h operation
31st August 2005
21st December 2005
3rd May 2006
23rd October 2006
29th January 2007
15th September 2007
DL-RAL Joint Accelerator Workshop
20 January 2009
Diamond storage ring main parametersDiamond storage ring main parametersnon-zero dispersion latticenon-zero dispersion lattice
Energy 3 GeV
Circumference 561.6 m
No. cells 24
Symmetry 6
Straight sections 6 x 8m, 18 x 5m
Insertion devices 4 x 8m, 18 x 5m
Beam current 300 mA (500 mA)
Emittance (h, v) 2.7, 0.03 nm rad
Lifetime > 10 h
Min. ID gap 7 mm (5 mm)
Beam size (h, v) 123, 6.4 m
Beam divergence (h, v) 24, 4.2 rad
(at centre of 5 m ID)
48 Dipoles; 240 Quadrupoles;
168 Sextupoles (+ H / V orbit correctors + Skew Quadrupoles );
3 SC RF cavities; 168 BPMs
Diamond Storage RingDiamond Storage Ring
DL-RAL Joint Accelerator Workshop
20 January 2009
The beam orbit is corrected to the BPMs zeros by means of a set of 168 dipole corrector magnets:
the BPMs can achieve sub-m precision; the orbit rms is corrected to below 1 m rms:
Storage Ring Closed Orbit < 1Storage Ring Closed Orbit < 1m m (first achieved 22th October 2006)(first achieved 22th October 2006)
Correction of linear optics with LOCOCorrection of linear optics with LOCO
((LLinear inear OOptics from ptics from CClosed losed OOrbit)rbit)
LOCO: fits quadrupoles to LOCO: fits quadrupoles to reproduce the theoretical reproduce the theoretical
closed orbit response matrixclosed orbit response matrix
circles = modelcircles = model
crosses = measuredcrosses = measured
0 50 100 150 200-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
Quad number
Str
engt
h va
riatio
n fr
om m
odel
(%
)
LOCO comparison
17th April 2008
7th May 2008 Modified version of LOCO with constraints on gradient variations (see ICFA newsletter, Dec’07)
- beating reduced to 0.4% rms
Quadrupole variation reduced to 2%Results compatible with mag. meas.
Emittance
2.78 (2.75) nm
Energy spread
1.1e-3 (1.0e-3)
Emittance coupling
0.5%
Emittance and energy spreadEmittance and energy spreadmeasured using two X-ray pinholes camerasmeasured using two X-ray pinholes cameras
Measured emittance very close to the theoretical values confirms the optics
Emittance coupling is now routinely corrected to 0.1% with LOCO
Closest tune approach 0, rms Dy 1 mm
13 Insertion Devices operational13 Insertion Devices operational
7 IDS in Phase I
and
first ID of Phase II
were installed and commissioned in
early 2007
Beamline ID Type
I02 U23 In-vacuum
I03 U21 In-vacuum
I04 U23 In-vacuum
I06 HU64 APPLE-II
I15 SCW 3.5 T Superconducting Multipole Wiggler
I16 U27 In-vacuum
I18 U27 In-vacuum
I22 U25 In-vacuum
I07 U23 In-vacuum
I11 U22 In-vacuum
I19 U22 In-vacuum
I24 U21 In-vacuum
I04.1 30.8 mm Short ex-vacuum
• 10 in-vacuum undulators
• 1 variable polarization APPLE-II device
• 1 3.5T superconducting wiggler
• 1 short ex-vacuum
mmx 3.121231.0 radradx 4.2241.0' mmy 6.04.61.0
xx 1.0 '1.0' xx yy 1.0 '1.0' yy
Beam stability should be better than 10% of the beam size and divergence
For Diamond nominal optics (at the centre of the short straight sections)
radrady 4.041.0'
but IR beamlines will have tighter requirements
for 3rd generation light sources this implies sub-m stability
Strategies and studies to achieve sub-m stability
• identification of sources of orbit movement
• passive damping measures
• orbit feedback systems
Orbit stability requirements at DiamondOrbit stability requirements at Diamond
Ground vibrations to beam vibrationsGround vibrations to beam vibrations
Amplification factor girders to beam: H 31 (theory 35); V 12 (theory 8);
1-100 Hz
Horizontal Vertical
Long StraightStandard Straight
Long StraightStandard Straight
Position (μm)
Target 17.8 12.3 1.26 0.64
Measured 3.95 (2.2%) 2.53 (2.1%) 0.70 (5.5%) 0.37 (5.8%)
Angle (μrad)
Target 1.65 2.42 0.22 0.42
measured 0.38 (2.3%) 0.53 (2.2%) 0.14 (6.3%) 0.26 (6.2%)
Significant reduction of the rms beam motion up to 100 Hz;
Higher frequencies performance limited mainly by the correctors power
supply bandwidth
Global fast orbit feedback at DiamondGlobal fast orbit feedback at Diamond
1-100 Hz
Standard Straight H
Standard Straight V
Position (μm)
Target 12.3 0.64
No FOFB 2.53 (2.1%) 0.37 (5.8%)
FOFB On 0.86 (0.7%) 0.15 (2.3%)
Angle (μrad)
Target 2.42 0.42
No FOFB 0.53 (2.2%) 0.26 (6.2%)
FOFB On 0.16 (0.7%) 0.09 (2.1%)
Summary of Current Machine StatusSummary of Current Machine Status
Target Achieved
Energy 3 GeV 3 GeV
Beam current 300 mA 300 mA Machine Development 250 mA User Mode
Emittance - horizontal 2.7 nm rad 2.7 nm rad - vertical 27 pm rad 4-50 pm rad ~ 27 pm in User Mode
Lifetime at 300 mA > 10 h ~ 18 h
Min. ID gap 7 mm 5-7 mm User Mode, dep. on ID
Stability < 10% 2.3% (H), 6.3% (V) No feedback of beam size 0.7% (H), 2.3% (V) Feedback, 1-100 Hz & divergence
DL-RAL Joint Accelerator Workshop
20 January 2009
Higher average brightness
• Higher average current
• Constant flux on sample
Improved stability
• Constant heat load
• Beam current dependence of BPMs
Flexible operation
• Lifetime less important
• Smaller ID gaps
• Lower coupling
Top-Up motivationTop-Up motivation
BPMs block stability
• without Top-Up 10 m
• with Top-Up < 1 m
Crucial for long term sub- m stability
Top-Up operation consists in the continuous (very frequent) injection to keep the stored current constant to prevent the natural beam current decay
User-Mode OperationsUser-Mode Operations
“Standard” operation: 250 mA maximum, 2 injections/day
DL-RAL Joint Accelerator Workshop
20 January 2009
Top-Up operationTop-Up operation
• First operation with external users, 3 days, Oct. 28-30th
• No top-up failures, no beam trips due specifically to top-up
• Now Top-Up is the regular user operation mode
DL-RAL Joint Accelerator Workshop
20 January 2009
Future Insertion DevicesFuture Insertion Devices
Beamline date Type
I12 Mar 094.2 T Superconducting Multipole Wiggler; contract with BINP;
Beamline extending outside diamond buliding
I20 Jun 092 x hybrid wigglers 2T, W83, construction in-house;
I07 End 09Cryogenic Permanent Magnet Undulator (U17.7) contract with
Danfysik. Will substitute the in-vacuum U23 device installed as a temporary measure.
I10 2010
Two APPLE II devices with 10 Hz polarization switching using 5-kicker scheme; engineering implications under study
2 girder changes
I13 2010
Two In-vacuum undulators with “double mini-beta” optics proposed;
beam dynamics and engineering implications under study.1 or 2 girder changes
Beamline extending outside diamond buliding
I09 2011
Helical undulator + in-vac. CPMU, with “double mini-beta” optics proposed; beam dynamics implications under study.
1 or 2 girder changes
A long straight sections is divided into two by a triplet of quadrupolesto achieve double mini beta in V and a virtual focus in H for coherence applications
Pos. ‘A’
Customised optics in long straight sectionsCustomised optics in long straight sections
I13 beamlineI13 beamline
DL-RAL Joint Accelerator Workshop
20 January 2009
Low – alpha optics
Higher Harmonic Cavities
RF voltage modulation
Femto–slicing
1) shorten the e- bunch 2) chirp the e-bunch + slit or optical compression
3) Laser induced local energy-density modulation
e– bunch
Crab Cavities
Synchro-betatron kicks
There are three main approaches to generate short radiation pulses in storage rings
Ultra-short radiation pulses in a storage ringUltra-short radiation pulses in a storage ring
0 10 20 30 40 50 60 70 80 90
-10
0
10
20
30
x
y
x
(m
)
s (m)0 10 20 30 40 50 60 70 80 90
-20
0
20
40
(c
m)
Low alpha opticsLow alpha optics
dzVdf
c
RFsz /2
3
If high current effects are negligible the bunch length is
= 1.710–4; V = 3.3 MV; = 9.6 10–4 z = 2.8 mm (9.4 ps)
z depends on the magnetic lattice (quadrupole magnets) via 610
1 dsD
Lx
We can modify the electron optics to reduce
(low_alpha_optics) 10–6
z 0.3 mm (1 ps)
15.2 15.4 15.6 15.8 16 16.2 16.4 16.6
-0.2
-0.1
0
0.1
0.2
(m
)
s (m)15.2 15.4 15.6 15.8 16 16.2 16.4 16.6
-5
0
5
(c
m)
100
102
104
10-6
10-4
10-2
100
102
disp
lace
men
t P
SD
[ m
2 /Hz]
frequency [Hz]
x
y
fs=340Hz
fs = 340Hz => α1 = 3.4×10-6, σL = 1.5ps
fs = 260Hz => α1 = 1.7×10-6, σL = 0.98ps
100
102
104
10-6
10-4
10-2
100
102
disp
lace
men
t P
SD
[ m
2 /Hz]
frequency [Hz]
x
y
fs=260Hz
Machine tests with 1 ps latticeMachine tests with 1 ps lattice
ε = 34 nm.rad; κ = 0.03%
Qx = 21.137; Qy = 12.397
Future WorkFuture Work
• Continue optics optimisation
maintain nominal optics, lifetime characterisation, injection efficiency;
characterisation of the non-linear optics (pinger magnet installed by end of 2007)
• Continue ID commissioning (Phase II and Phase III ID installation till 2014)
optics compensation vs gap, DA effect, lifetime vs gap, frequency map vs gap
ID request operation at 5 mm gap
• High current operation (300 mA) and TMBF
impedance database; characterization of the instabilities (multi-bunch, single bunch)
• Maintain/Improve Top-up, FOFB performance
• Low alpha optics for users
Thanks to R. Fielder, E. Longhi, I. Martin, B. Singh, J. Rowland and staff from Diagnostics, Controls, Operations, IDs, RF, …
DL-RAL Joint Accelerator Workshop
20 January 2009