1. Beam position measurements at synchrotron light sources
Victor Smaluk
NSLS-II

2. Requirements eeFACT 2016 10 – 100 m 1 μrad 10 – 100 μm 5 – 10 m
Resolution, micron or submicron level – orbit feedback systems Beam stability requirement: 5-10% of the beam size.
10 – 100 m
1 μrad
10 – 100 μm
5 – 10 m
>10 kW/mrad2
BPM
Reliability – active interlock systems
Active Interlock System protects the storage ring and the frontend components from damage by synchrotron radiation; it drops the beam if its orbit exceeds the safety limits (e.g. 0.5 mm and 0.25 mrad at IDs).
Fast data transfer and processing – fast orbit feedback systems
Flexibility – machine commissioning, lattice optimization and beam studies
Daresbury, UK Oct 2016

3. Button-type Electrostatic Pickup Sensitivity
eeFACT
2016
Beam charge
Image charge
Image current
Button impedance
Beam-induced voltage
Daresbury, UK Oct 2016

4. Button-type Electrostatic Pickup Nonlinearity Correction
eeFACT
2016
E.Bekhtenev, BINP
linear formula
polynomial linearization
Daresbury, UK Oct 2016

5. BPM Signal Processing eeFACT 2016 Daresbury, UK 24-27 Oct 2016
Digital signal processing won the battle against analog schemes
DSP (BINP, EPAC 1996 TUP008L)
FPGA (NSLS-II, IBIC 2014 WECYB2)
Daresbury, UK Oct 2016

6. BPM Signal Processing Electronics
eeFACT
2016
E (GeV)
C (m)
BPMs
MAX IV
Sweden 3
528
200
Libera Brilliance+
Taiwan Photon Source
Taiwan
518.4
168
PETRA III
Germany 6
2304
227
Libera Brilliance
ESRF
France
844.4
224
ALBA
Spain
268.8
120
Diamond Light Source UK
561.6
Libera Electron
SSRF
China
3.5
432
150
SOLEIL
2.75
354.42
ELETTRA
Italy 2
259.2 96
Australian Synchrotron
Australia
216 98
SPRING-8
Japan 8
288
KEK
APS
USA 7
1104
360
APS FPGA-based
NSLS II
792
180
NSLS-II FPGA-based
BESSY-II
1.9
240
112
Helmholtz-Zentrum Berlin, BxB
CHESS (CESR)
768
100
Cornell, BxB
Σ=2664
Daresbury, UK Oct 2016

7. NSLS-II BPM Module eeFACT 2016 Daresbury, UK 24-27 Oct 2016
J.Mead, IBIC 2014 WECYB2
Daresbury, UK Oct 2016

8. Analog Front End eeFACT 2016 Daresbury, UK 24-27 Oct 2016
J.Mead, IBIC 2014 WECYB2
Daresbury, UK Oct 2016

9. Signal Processing eeFACT 2016 Daresbury, UK 24-27 Oct 2016
J.Mead, IBIC 2014 WECYB2
Daresbury, UK Oct 2016

10. Resolution eeFACT 2016 Daresbury, UK 24-27 Oct 2016
Libera Brilliance+ BPM
NSLS-II BPM
W.Cheng, IBIC 2015 THALA02
Daresbury, UK Oct 2016

11. BPM System Configuration
eeFACT
2016
Example: NSLS-II
180 BPMs
30 BPM IOCs
30 Cell Controllers
1 Fast Active Interlock system
Daresbury, UK Oct 2016

12. One Cell Configuration
eeFACT
2016
J.Mead, IBIC 2014 WECYB2
Daresbury, UK Oct 2016

13. Fast Orbit Feedback eeFACT 2016 Daresbury, UK 24-27 Oct 2016
O.Singh, IBIC TUBL1
Daresbury, UK Oct 2016

14. Active Interlock eeFACT 2016 Daresbury, UK 24-27 Oct 2016
K.Ha e.a., IPAC THPOY048
Data for most-mortem analysis
Daresbury, UK Oct 2016

15. Beam Post Mortem Analysis
eeFACT
2016
G.Wang, NSLS-II
Post mortem data are used to find beam dump source:
Cavity trip (vacuum, Equipment Protection System, Personnel Protection System)
Equipment Protection System (vacuum, temperature, utilities…)
Personnel Protection System (doors, radiation alarms)
Power Supplies
Active Interlock
Power dips
Daresbury, UK Oct 2016

16. “Invisible” Measurements of Lattice Parameters
eeFACT
2016
G.Rehm, BIW 2010 MOCNB01
A small controlled sinusoid disturbance using an actuator (stripline, corrector magnet). Detection of this frequency component in a data stream (bunch-by-bunch position, turn-by-turn position, fast orbit data) using a digital detector. Accumulation over a certain measurement period, duration of which determines bandwidth and thus measurement noise.
Measured parameters
betatron tunes
chromaticity (by measuring relative amplitude of a synchrotron sideband)
betatron functions, amplitude/phase
corrector orbit response
Daresbury, UK Oct 2016

17. AC LOCO – Effective Technique of Lattice Correction
eeFACT
2016
Measurement
Sine-wave (AC) beam excitation via fast correctors
Possibility of simultaneous excitation of many correctors with different frequencies
Recording BPM fast acquisition (10 kHz) data (all BPMs – 1 response vector)
Synchronous detection of the beam oscillation amplitude
Correction – standard LOCO technique
Fitting the measured orbit response matrix to the model
Quadrupole strengths
BPM gains and rolls
Corrector gains and rolls
r.m.s. amplitude error at 20 Hz (5 s, samples)
beam excitation by 23 correctors with 2 Hz separation
Daresbury, UK Oct 2016

18. Crosscheck of Lattice Correction Techniques
eeFACT
2016
Orbit
Linear Optics from Closed Orbits (LOCO) J.Safranek, NIMA 388, p.27 (1997)
AC LOCO
Turn-by-turn
weighted correction of betatron phase and amplitude
independent component analysis J.X.Huang e.a., PRSTAB 8, (2005)
model-independent analysis J.Irwin e.a., PRL 82 (8) , p.1684 (1999)
driving-terms-based linear optics characterization Y.Hidaka e.a., NAPAC-2016 (TUPOB52)
Daresbury, UK Oct 2016

19. Gating BPM ADC Signals: Resolution Improvement
eeFACT
2016
B.Podobedov, IBIC 2015 TUCL02
Standard BPM signal processing looks at the entire turn (2.64 μs, 310 ADC channels)
Applying a time gate results in resolution improvement by factor of 3 to 4
Daresbury, UK Oct 2016

20. Gating BPM ADC Signals: Application
eeFACT
2016
Y.Hidaka, NAPAC MOA2CO03
Measurement of tune shift with amplitude from BPM data with a single kicker pulse
Unique NSLS-II BPM capability: Gated turn-by-turn BPM data that resolve groups of bunches within a turn
The single-shot method eliminates possible errors of tune shift measurements caused by machine drift / jitter.
Daresbury, UK Oct 2016

21. Thank you for your attention!
eeFACT
2016
Thank you for your attention!
Daresbury, UK Oct 2016