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3rd International Workshop on Beam Orbit Stabilization - IWBS2004 December 6-10, 2004 Hotel Kirchbühl, Grindelwald, SWITZERLAND Orbit Stabilization at Taiwan Light Source Kuo-Tung Hsu December 6, 2004. NSRRC Accelerator. BM2. SRF Cavity (Dec. 2004). IASW6 (3.5 T) x 3 sets. EPU5.6. U5. - PowerPoint PPT Presentation
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3rd International Workshop on Beam Orbit Stabilization - IWBS2004December 6-10, 2004
Hotel Kirchbühl, Grindelwald, SWITZERLAND
Orbit Stabilizationat
Taiwan Light Source
Kuo-Tung Hsu
December 6, 2004
NSRRC Accelerator
Storage Ring(1.51 GeV)
Booster Ring(1.51 GeV)
LINAC
Transport Line
Bending Magnet
Quadrupole Magnet
Pulsed Injection Magnet
Sextupole Magnet
SRF Cavity
Insertion Device
BM2
BM1
W20 (1.8 T)
U9 (1.25 T)
SWLS (6 T)
EPU5.6 U5 SRF Cavity(Dec. 2004) SW6 (3.2T)
IASW6 (3.5 T) x 3 sets
December 20044 Conventional IDs
2 Superconducting IDs22 Beamlines
56 End-stations
Lattice type Combined function Triple Bend Achromat (TBA)Operational energy 1.5 GeVCircumference 120 mRF frequency 499.654 MHzHarmonic number 200Natural beam emittance 25.6 nm-radNatural energy spread 0.075%Momentum compaction factor 0.00678Damping time Horizontal 6.959 ms Vertical 9.372 ms Longitudinal 5.668 msBetatron tunes horizontal/vertical 7.18/4.13Natural chromaticities Horizontal -15.292
Vertical -7.868Synchrotron tune 1.06*10-2 (SRF, 1.52*10-2)Bunch length 9.2 mm (Doris Cavities, 800 kV)
6.5 mm (SRF, 1.6 MV)Radiation loss per turn (dipole) 128 keVNominal stored current (multibunch) 200 mA (~2004), 300~400 mA (2005~)Number of stored electrons (multibunch) 5*1011 (SRF cavity, 1012)
Major Parameters of the Storage Ring
Efforts to Improve Beam Stability
Coupled-bunch instability :
RF gap voltage modulation (~ October 2004)
Superconducting RF (December 2004 ~)
(to accompany double the stored beam current).
Coupled bunch feedback system
Orbital stability:
Source Elimination
Ambient temperature, Water temperature,
Enhance data acquisition system, Vibration
elimination, Power quality improvement ,
Power supply improvement …etc.
Orbit feedback system
Top-up injection
4. Vibration
6. Control System
5. Sensors Implementation
3. Thermal-Mechanical Effects
2. Heat Source Stabilization
1. Utility Capacity Improvement
<± 0.1 ℃<1 μm rms
<0.3%
<± 0.1 ℃(drift<5μm)
~± 0.15 ℃<3μm rms
~0.5%
<± 0.2 ℃(drift~20μm)
~± 0.25 ℃>± 1 ℃(drift>50μm)
>1%
Performance, ΔT
orbit
ΔIo/Io
2002 20012000199919981997
Utility building #2 constructionCHW capacity improved
CTW, CHWStability
Injector energy upgradefull energy injection
EPU air temp.U5 air temp.
SCADA implementationelectrical sensors
Water control system upgradeVF controller implementation
Utility data archive system
AHU controller upgradeAHUs reorganized
Air temp. sensors Position sensors
Global effect studies(air/water temp., cable heat)
Girder, thermal insulator , vacuum chamber, SR heat mask
BL-, RF-DIW temp.
AHU, crane vibration pre-reduced Damping study Floor meas.
Piping improv.
Program initiation
Power supply heating
ΔI monitor
Mechanical Related Source Elimination
(2003)~ 0.06%
(J. R. Chen, et. al.)
Magnet (Water Temperature)
100 200 300 40022
24
26
28
Mag-Water Temp. Beam Position
Time(min.)
Tem
pera
ture
(¢J)
0.22
0.23
0.24
0.25
0.26
Posi
tion
(mm
)
Caused by the temperature fluctuations of magnet cooling waterMagnet deformed ~ 10μm/ ℃Induced beam orbit drift: 5 ~ 50 μm / ℃
Current statusCooling water temp.: ~ ± 0.1℃
Girder Displacement
• Main cause: air temperatureSensitivity to air temp.: ~10 μm / ℃Induced beam orbit drift: 20-100 μm / ℃
• Current status: < ± 0.1 μm per 8 hr shift Air temp. : < ± 0.1℃(utility control system improved) Thermal insulator jacket
-200 0 200 400 600 800 1000 1200 14000.92
0.94
0.96
0.98
1.00
-200 0 200 400 600 800 1000 1200 140024.0
24.5
25.0
25.5
26.0
Beam Position
mm
min
Air TemperatureD
eg
ree
(C
)
0 25 50 75 10024
25
26
27
28
Dis
plac
emen
t (£g
m)
Tunnel Air Temp. Girder Disp. Outer Girder Disp. Inner
Time (Hours)
Tem
pera
ture
(¢J)
-20
-15
-10
-5
0
Expansion of Vacuum Chamber
• Caused by synchrotron light irradiation. Sensitivity to water temp.: ~ 10 μm / ℃
Move the girder (~ 0.3μm/ ) and BPM (~ 1℃ μm/ )℃ Induced beam orbit drift: ~10-30 μm / ℃
• Current statusVacuum cooling water temp.: ~ ± 0.5℃
0 6 12 18 2419.5
20.0
20.5
21.0
21.5 Girder Displacement Beam Current
Time (Hours)
Dis
plac
emen
t (£g
m)
0
100
200
Bea
m C
urre
nt (m
A)
0 200 400 600 800 1000 1200 1400-0.08-0.06-0.04-0.02
0 200 400 600 800 1000 1200 14000.51.01.52.0
0 200 400 600 800 1000 1200 14002425262728
0 200 400 600 800 1000 1200 14000
100200
Beam Position
mm
min
BPM Displacement
um
Vac-chamber Temp
Tem
p (
C)
Beam Current
mA
Power Supply Related High Frequency Orbital Noise(Source Elimination)
@ 136 mA (August 22, 2001)
Beam Spectrum Observation
High Frequency Corrector Power Supply Noise
0 100 200 300 400 500 600 700 80010
-7
10-6
10-5
10-4
10-3
10-2
Frequency ( Hz )
Ou
tpu
t c
urr
en
t ri
pp
le
( a
mp
ere
)
0 0.5 1 1.5 2 2.5
x 104
10-7
10-6
10-5
10-4
10-3
10-2
Frequency ( Hz )
Ou
tpu
t c
urr
en
t ri
pp
le
( a
mp
ere
)
Typical Corrector Spectrum
0 100 200 300 400 500 600 700 80010
-7
10-6
10-5
10-4
10-3
10-2
Frequency ( Hz )
Ou
tpu
t c
urr
en
t ri
pp
le
( a
mp
ere
)
0 0.5 1 1.5 2 2.5
x 104
10-7
10-6
10-5
10-4
10-3
10-2
Frequency ( Hz )
Ou
tpu
t c
urr
en
t ri
pp
le
( a
mp
ere
)Before Improve
After Improve
(K.B. Liu et al.)
BeforeImprove
RMS=0.03%
RMS=0.16%
Mar.08,2002186mA
June 13, 2002185mA
Observation at Infrared Beamline
AfterImprove
BeforeImprove
AfterImprove
(Y. C. LO, et al.)
Software Environment for BPM Data Access
Closed Orbit Server
Static Database Dynamic Database(Slow Orbit, 10 update/sec)
Device ControlService ProgramStatic Database Service Program
Data UpdateService Program
DatabaseLoggingProgram
Real-TimeTrend Display
LabVIEWInterface
MatlabMEX
Interface
MX-BPM Hardware
Control Ethernet
SoftwareComponents
OnControl Consoles
BPMVMEsCrates
(PPC/LynxOS)
ConsolesComputers(Compaq WS/Unix)
(PC/Linux)
Self-ConfigurationTable
Data Acquisition
Reflective Memory
(RM)Fast Orbit, 1 K update/sec
Machine ParametersService Routines
Machine Modeling(MPAP,APAP)Control Applications
Data Access Routines
Data Access Routines
April 2003
MatlabScripts
AP
MATLAB
LabVIEWVI
LabVIEW
System StatusDisplay
Alarm CheckingProgram
Parameter PageProgramData Logging
& ArchivingHardware DiagnosticsProgram
AP
Turn-by-Turn Server Program
Closed Orbit Data
Reflective Memory
(RM)Fast Orbit, 1 K
update/sec
DBPM Hardware, LR-BPM Hardware
Mode Control BPM Data
Control Program
Toother
DBPMnodes
ClosedOrbit
Server+
MX-BPMData
Acquisition
DBPMLR-BPM
DataAcquisition
Node
Turn-by-TurnData Access
Environment of BPM System
Orbit Feedback System Architecture
ControlNetwork
ControlConsoles
PC/Linux
VME
HOST
16BitDAC
RM/DMA
Private Ethernet Switch
Reflective MemoryHub
Keithley 2701PBPM Front-end
Keithley 2701 PBPM Front-end
FeedbackVMECrate
Corrector ControlVME CrateOrbit Acquisition
VME Crates
RM/DMA
16BitDAC
16BitDAC
Electron BPM(MX-BPM & DBPM) Correction Magnet Power Supply
Photon BPM
VME
HOST
RM/DMA
16BitADC
16BitADC
16BitADC
Tim
ing G
enerator
VM
E H
ostPow
erPC 7410
RM/DMA
VME
HOST
Feedback Data Capturer
VME Crate
VM
E H
ostPow
erPC 7410
PC/WindowsWS/UnixWS/Unix
Local RAM Disk
VME
HOST
RM/DMA
16BitADC
16BitADC
Tim
ing G
enerator
16BitADC
Fiber Interface
Orbit Feedback System Summary* 22 correctors + 30 BPMs for both plane* Using measured response matrix* Singular Value Decomposition (SVD) approach to invert the response
matrix* Proportional, Integral and Derivative (PID) control algorithm* Orbit acquisition rate 1 kHz* Loop bandwidth is about 5 Hz now (30 Hz before December 2003)* Unified system for global feedback and local feedback system* Remote enable/disable of the feedback loop* Orbit excursion reduced to less than ~ um level for ID operation
- U5, U9 and EPU5.6* Suppress orbit leakage due to non-ideal dynamic local bump
- EPBM* Prototype local feedback loop by using e-BPMs
Orbit Feedback System Summary (cont.)* DSP feedback engine was replaced by general purpose PPC moduleUser friendly development environmentLift maintenance difficultsSlightly increase jitter < 50 sec (DSP < 10 sec)
* Robustness enhancement of the feedback loop
BPM Check
RMS, data change rate, …etc
Limited correct setting range
Problems and Plan of the Orbit Feedback SystemMajor Problems : * Loop bandwidth is too small right now
=> cannot eliminate mechanical related oscillation
=> Limited gap/phase changing speed of IDs
Short-term Plans: * Increase sampling rate o 2 kHz to 4 kHz * Modify corrector power supply regulation loop * Increase loop bandwidth > 100 Hz
Closed Orbit : ~10 m rms with DC correction schemes. (P
eace Chang et al.)
Orbit distortions: < 10 m rms during insertion gap scan c
an be compensated for using look-up correction tables. (Pe
ace Chang et al.)
Beam orbit stability: a few m level (peak-to-peak) with a gl
obal feedback system. (C. H. Kuo et al.)
Closed Orbit and Orbit StabilityClosed Orbit and Orbit Stability
e-
Power Supply
#1
Power Supply
#2
Power Supply
#4
Power Supply
#3
EPBM Model Enable
Bump Amplitude
Control (0-5 V)
Bump Coefficient
(± 10 V)
Block Diagram of Control Electronics for
Elliptical Polarization from Bending Magnet (EPBM) ProjectDRAFT
Ratio Amplifier
x 4#1 #4#3#2
BM2 Bending MagnetEPBM VC #1
EPBM VC #2
EPBM VC #3
EPBM VC #4
EPBM Control Electronics
SYNC to Experimental
Station
Clock Generator
12 12
Corrector Strength
ILC12ILC03
#1 #2 #3 #4#1 #2 #3 #4
Line Driver x 2
EPROM
12 Bits Counter
t1
t2
t2 : user specify
Ratio Amplifier
Instrumentation Amplifier x 812 Bits DAC
++ + +
t1 : 40 msec
Polarization Control
EPBM Mode
Request
EPBM Model Request
EPBM Mode Enable
3.4o
1220 mm460 mm 375 mm 540 mm 345 mm
325 mm 135 mm 170 mm 175 mm
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
0 5 10 15 20 25 30 35 40 45 50
Ver
tical
Pos
ition
(m
m)
BPM Index
Difference Orbit - EPBM 'on', DGFB 'off'
"ep0925f.dat"
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
0 5 10 15 20 25 30 35 40 45 50
Ver
tical
Pos
ition
(m
m)
BPM Index
Difference Orbit - EPBM 'on', DGFB 'on'
"ep0925g.dat"
* EPBM dynamic bump with feedback
EPBM flip bump without feedback
Eliminated Orbit Leakage for EPBM Operation
(C.H. Kuo et. al.)
Insertion Devices in the TLS Storage RingInsertion Devices in the TLS Storage Ring
Insertion Device SWLS EPU5.6 U5 SW6 W20 U9 IASW
Location Section S1 S2 S3 S4/RF S5 S6 Arc 2,4,6
Type SC Pure Hyb. SC Hyb. Hyb. SC
Magnet Length (M) 0.835 3.9 3.9 1.404 3.0 4.5 0.85
Period Length λ (cm) 25 5.6 5 6 20 9 6
(Min.) Gap (mm) 55 18 18 18 22 18 18.5
Number of Periods 1.5 66 76 16 13 48 7.5
Maximum By (Bx) Field (Tesla)
6 0.67 (0.45)
0.64 3.2 1.8 1.25 3.5
Photon Energy (eV)
[Used Range]
Min. 4000 80 60 5000 800 5 5000
Max. 38000 1400 1500 14000 15000 100 14000
Defection Parameter Ky (Kx)
190.5 3.52(2.37)
2.99 17.9 33 10.46 19.6
Vertical Tune Shift Δν Vertical Tune Shift Δν (Horizontal Tune Shift)(Horizontal Tune Shift)
0.05040.0504(-0.014)(-0.014)
0.0110.011(-0.012)(-0.012)
0.0080.008 0.0360.036 0.0360.036 0.0330.033 0.050.05
Installation Date Apr.2002
Sep.1999
Mar.1997
Dec.2003
Dec.1994
Apr.1999
2005 The photon flux vs. photon energy of bending magnets and IDs at TLS. Two Taiwan beamlines, SP8-BM and SP8-U3.2, at Spring 8 are also depicted
withFeed-forward
TuneCorrection
withoutFeed-forward
TuneCorrection
Orbit stability of the NSRRC Storage RingOrbit stability of the NSRRC Storage Ring
With the follow-gap look-up table and global orbit feedback system, the orbit drift of the field scan of U5, U9 and EPU5.6 can be reduced from a few hundred microns to a few microns. When the gaps of U5, U9 and EPU5.6 are scanned from 19, 21, and 21 mm to 39, 41, and 41 mm, the closed orbit distortions indicated by the R4BPM5X (blue) and R3BPM3Y (green), those are used in the faster orbit feedback system, are within 2 microns in both horizontal and vertical planes.
(Peace Chang, et. al.)
Photon Beam Stability Monitor (Io / Io)
BM3
BM3
VFM
VFM
50 um pinhole
Sensitive toBeam size instabilityOrbit instabilityEnergy instability
Signpost of overall beam stability form users’ viewpoints
Demagnification factor : 3
PhotoDiode
Thermal Deformation
Backlash
Driver Mechanism(Optimization)
Electron Beam Stability(Transverse,Longitudinal,Beamsize, …)
History of the Photon Beam Stability (I0/I0)
May Jan Jan Jan2001 2002 2003 2004
0
20
40
60
80
100
Ach
ieve
d P
erce
nta
ge
in U
ser
Tim
e
< 1 % <0.5 % < 0.3 % < 0.2 % < 0.1 % < 0.05 %
long shutdown long shutdown
Improve cavity temperature control at 30% user time
U5, U9, EPU dynamic tuning at 100% user time
Relax U5, U9, EPU dynamic tuning speed
(K.K. Lin et. al.)
1130 1140 1150 1160 1170 1180 1190 1200197
198
199
200
201
202
203
Time (min.)
Sto
red
Beam
Cu
rren
t (m
A)
-15
-10
-5
0
5
Orb
it C
han
ge (
mic
ron
)
Date: Dec. 31, 2002 Top-up mode Test
R4BPM5X (blue line)
*Orbit change referred to the data at 1130 minute is taken with 10 Hz sampling rate.
R3BPM3Y (red line)
Stored beam current *Injection threshold current is 198 mA
Top-up injection scheme planned. Feasibility demonstrated.
(G.H. Luo et. al.)
Top-up Injection ProjectTop-up Injection Project
Experiment of Top-up injection
Filling pattern at the beginning of top-up injection
Filling pattern at the end of top-up injection
User’s shift decay mode Test of top-up mode
Zoom in, injection interval 2 min.
(G.H. Luo et. al.)
Cooling Water and Chamber Temperature
Outlet cooling water temperature
Chamber’s temperature
Top-up test run
(G.H. Luo et. al.)
Compound Displacement of the of Beam Position Monitor Reading
Stored beam current in mA
R1 BPM3 X-displacement in m
R1 BPM3 Y-displacement in m
x ~15 m
y ~5 m
-Intensity dependency of BPM electronic and BPM support fixtures (~ m)-Filling pattern dependency of BPM electronics (~ m)-RF gap voltage condition variation-BPM support structure (~ 10 m)-Thermal related (~ 10 m)
Top-up test run
(G.H. Luo et. al.)
R1BPM1Y
R2BPM7Y
R6BPM4Y
Vertical Beam Position Variation
20 m
20 m
20 m
Top-up test run
R1BPM1X
R4BPM3X
R3BPM8X
Horizontal Beam Position Variation
20 m
9 m
5 m
Top-up test run
Renew 1.5 sec half-since injection kicker to reduced jitter and to improve waveform matching .
Gate of the orbit feedback loop is a provincial solution to remedy mismatching problem of the injection kickers.
User experiment with injection gate and without is performed, acceptable results get up to now.
Improve gun pulser and linac performance to improve filling pattern control.
Studies of the injector reliability, injection efficiency, and minimization of orbit perturbation during injection, etc., are ongoing.
Top-up operation is scheduled in late 2005.
Top-up Injection PlanTop-up Injection Plan
Electron Energy 3 ~ 3.3 GeV
Current 400 mA at 3 GeV or 300 mA at 3.2 GeV (Top-up injection)
SR Circumference 518.4 m (h = 864 = 25·33 , dia.= 165.0 m)
BR Circumference 499.2 m (h = 832 = 26·13, dia.= 158.9 m)
Lattice 24-cell DBA
Straight-section 10.5 m x 6 ( σv = 10.5 μm, σh = 160 μm) 6 m x 18 ( σv = 8 μm, σh = 110 μm) 3 m x 12 ( σv = 4.5 μm, σh = 250 μm; In-achromat)
Bending-section x 12
Emittance < 2 nm·rad at 3 GeV (Distributed dispersion)
Coupling 1 %
RF Frequency 500 MHz
RF Max. Voltage 4.8 MV (4 SRF cavities)
RF Max. Power 720 kW (4 SRF cavities)
Site NSRRC in Hsinchu Science Park , Taiwan
Building 223 m OD (700 m circumference) 139 m ID (437 m circumference)
Parameters of the Proposed Taiwan Photon Source
Sub-m orbital performance is one of a design goal.
Summary
* To achieve m (sub-m) orbital performance is a short term goal at TLS.* Further develop of fast orbit feedback system is needed in following area:
• Corrector PS improvement• High sampling rate (~ 2 KHz/4 KHz)• PS control interface• BPM system improvement in engineering as well as software functionality.
* Top-up operation mode is scheduled, beam orbit stability will be improve further.* Sub-m orbital performance is one of a challenge for the newly proposed 3 ~ 3.3 GeV Taiwan Photon Source
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