0. Changes to the PS RF system
H. Damerau
Many thanks for discussions and input to
L. Arnaudon, D. Cotte, S. Hancock, R. Maillet, M. Morvillo, M. Paoluzzi, D. Perrelet, S. Rains, C. Rossi, S. Totos 55
BE/OP Shutdown Courses 2014
04 April 2014

1. Overview Introduction Global beam control system modifications
RF systems for manipulations
Global beam control system modifications
Injection bucket control
RF controls renovation
10 MHz RF system
Voltage control and 1-turn delay feedback loops
Tuning group restructuring
10 MHz matrix control, spare cavity selection and linked timing
High-frequency and wide-band RF systems
20, 40, 80 MHz and 200 MHz
Wideband cavity for longitudinal damper
Summary

2. Overview Introduction Global beam control system modifications
RF systems for manipulations
Global beam control system modifications
Injection bucket control
RF controls renovation
10 MHz RF system
Voltage control and 1-turn delay feedback loops
Tuning group restructuring
10 MHz matrix control, spare cavity selection and linked timing
High-frequency and wide-band RF systems
20, 40, 80 MHz and 200 MHz
Wideband cavity for longitudinal damper
Summary

3. Introduction What has changed for the RF systems after LS1? PS
Protons and ions to SPS (and LHC)
Protons to AD and nTOF target
Protons from PSB
Protons to fixed target experiments
Pb54+ (future: Ar11+, Xe39+) from LEIR
Beams from single bunch to 72 bunches, flexible longitudinal pattern
Intensity range from about 109 to 3 · 1013 particles per cycle
Major bunch shortening along the cycle, from 180 ns to 4 ns (45 times!)
After LS1: BCS, BCMS, PBC, etc.
What has changed for the RF systems after LS1?
What to do with the modified RF systems?  Steven’s lecture

4. RF Systems to perform manipulations
Acceleration
2.8 – 10 MHz
200 MHz
Longitudinal blow-up and 200 MHz structure for SPS
13/20 MHz
80 MHz
40 MHz
RF Manipulations
to SPS PS
 24 (+1) cavities from 2.8 to 200 MHz

5. Overview Introduction Global beam control system modifications
RF systems for manipulations
Global beam control system modifications
Injection bucket control
RF controls renovation
10 MHz RF system
Voltage control and 1-turn delay feedback loops
Tuning group restructuring
10 MHz matrix control, spare cavity selection and linked timing
High-frequency and wide-band RF systems
20, 40, 80 MHz and 200 MHz
Wideband cavity for longitudinal damper
Summary

6. Injection bucket selection
PA.DCNBINJ
Bunches from PSB must be placed into the correct buckets
Batch compression works only for even number of bunches
1 turn
Bucket number control during both transfers PSB  PS

7. Synchronizing PSB and PS – 1st injection
Tagged clock
DDS h128
MHS DDS
R. Garoby, Multi-harmonic RF Source for the Anti-proton Production Beam of AD, CERN PS/RF/Note 97-10
frev, closed loop
RF directly to cavities (one DDS per cavity)
Bucket number control … …
fRF, inj. = · MHz
Inj. Bucket selection
Sync. on h = 1, fix bucket #
Df (phase loop)
Df (injection synchro.)
4 ms/div 1. 2.
Inj.
MHS h = 1
Shifted trains to PSB, 1st inj.
MHS hPL = 9
Lock f- loop on inj. synth.
Generate synchronous h1, h4 and h8 for PSB, while locking f-loop on h9

8. Synchronizing PSB and PS – 2nd injection
Tagged clock
DDS h128
MHS DDS
R. Garoby, Multi-harmonic RF Source for the Anti-proton Production Beam of AD, CERN PS/RF/Note 97-10
frev, closed loop
RF directly to cavities (one DDS per cavity)
Bucket number control … …
Inj. Bucket selection
Sync. on h = 1, fix bucket #
MHS h = 1
Shifted trains to PSB, 2nd inj.
MHS hPL = 9
Generate synchronous h1, h4 and h8 for PSB, while locking f-loop on h9

9. Overview Introduction Global beam control system modifications
RF systems for manipulations
Global beam control system modifications
Injection bucket control
RF controls renovation
10 MHz RF system
Voltage control and 1-turn delay feedback loops
Tuning group restructuring
10 MHz matrix control, spare cavity selection and linked timing
High-frequency and wide-band RF systems
20, 40, 80 MHz and 200 MHz
Wideband cavity for longitudinal damper
Summary

10. Major renovation of LLRF controls
Profit from global controls renovation (ACCOR) to move front-ends for PS beam controls to central building
Before
The plan…

11. Major renovation of LLRF controls
Profit from global controls renovation (ACCOR) to move front-ends for PS beam controls to central building
During…
Back on…
E. Said and installation team
Close collaboration between BE/CO and BE/RF

12. Migration of controls devices ‘Transparent’ migration
Obsolete GM class
New class
Timings
PTIM-V
LTIM
Functions
GFAS
CVORB
Digital bit controls
DIGIO
CGDIO_B (bit)
Digital selectors
CGDIO_E (enum)
Digital controls
DIGCTL
CGDIO_C (cont.)
Pentek synthesizer
V346
10 MHz matrix
RFMAT
MATRF
‘Transparent’ migration
67 CVORB function channels
~220 physical timing channels, ~1240 timings in total (multi-pulses)
~35 Further devices: digital controls, RF synthesizer, etc.
Kontron PC front-end for MIL1553 loops (all cavities)  on/off/reset
About 10 kilometers of new cables, but in about 250 smaller pieces

13. Ready for new RF manipulations Should be sufficient for the future
Controls upgrade from TG8 to CTRV:
Each function with restarts now 16 instead of 8 restart timings
Twice more complicated RF manipulations possible:
Sequence of 16 phase loop harmonics
Sequence of RF harmonics
RF manipulations twice as complicated as before LS1 (2  BCMS)
Should be sufficient for the future
Should be sufficient for the near future?

14. Overview Introduction Global beam control system modifications
RF systems for manipulations
Global beam control system modifications
Injection bucket control
RF controls renovation
10 MHz RF system
Voltage control and 1-turn delay feedback loops
Tuning group restructuring
10 MHz matrix control, spare cavity selection and linked timing
High-frequency and wide-band RF systems
20, 40, 80 MHz and 200 MHz
Wideband cavity for longitudinal damper
Summary

15. PS 10 MHz feedback overview
Final Amplifier, 10 MHz Cavity, Fast Wideband FB H
Gap Return
- Fast wide-band feedback
around amplifier (internal)
 Gain limited by delay
- 1-turn delay feedback
 High gain at n  frev
- Slow voltage control loop (AVC)
 Gain control at fRF
Drive
DAC
1TFB
ADC
DAC
AVC h
h200
Vprog (digital)
D. Perrelet

16. Voltage control (AVC) loop
Pre-LS1 hardware required analog voltage program
Regulation characteristics not optimum for fast voltage jumps
RF from beam control
P. Maesen, PS/RF/Note 94-25
Analog voltage control:
AVC loop functionality
Interlocks
Loop filter
Pre-LS1
Vprog (analog)
Upgrade to fully digital implementation of AVC loop
Migrate interlock part to separate surveillance hardware

17. Digital voltage control (AVC) loop
Digital voltage control loops integrated into 1-turn delay feedback HW
Separate surveillance module to assure hardware safety
RF from beam control 
Digital PID
h (digital)
Veto
Vprog (digital)
Non-I/Q detector
D. Perrelet
Harmonic number functions PA.GSHA/B/C required for all beams
M. Haase

18. Principle of the 1-turn delay feedback
Classical feedback limited by unavoidable delay
BUT: Impedance reduction of cavities only needed at frev harmonics
D. Boussard, G. Lambert, PAC83, pp
Comb filter for high gain at frev harmonics
Delay circuit to correct total feedback delay to a full turn
Additional notch filter to cancel feedback gain at fRF

19. New 1-turn delay feedback
No need for:
Multiple clocks, avoiding double sampling at 4 fRF and 80 frev
Wide-range clock phase locked loops
External delay cables
Increased resolution of signal processing from 10 to 14 bits
Ready for proton beams at any harmonic number
No need to start from h = 8 (limitation in old system)
Compatible with all LHC-type beams
Integrated electronic delay generation
Possibility to raise feedback gain by firmware improvements
Include a digital AVC in the firmware to replace analog hardware

20. Flexible feedback board development
D. Perrelet
Versatile board:
4 ADC/DAC channels with powerful FPGA
Delay line chains to complete delay of 1-turn
CVORB and fast serial ports for connections
Further/future applications: PS transverse feedback, coupled-bunch feedback, 1-turn delay feedback for 20/40/80 MHz systems and transverse dampers of PSB, AD, LEIR

21. Installation
Four new VME crates installed in building 359 (one per tuning group)
Example for tuning group B (cavities C56, C66, C76 and C81):
D. Perrelet
All 10 MHz cavities equipped:
 AVC loop commissioning ongoing, then 1-turn delay feedback

22. Overview Introduction Global beam control system modifications
RF systems for manipulations
Global beam control system modifications
Injection bucket control
RF controls renovation
10 MHz RF system
Voltage control and 1-turn delay feedback loops
Tuning group restructuring
10 MHz matrix control, spare cavity selection and linked timing
High-frequency and wide-band RF systems
20, 40, 80 MHz and 200 MHz
Wideband cavity for longitudinal damper
Summary

23. Change of tuning group configuration
10 MHz require a tuning current of up to 3000 A to cover 2.8…10 MHz
Multiple cavities in series to reduce tuning power supplies:
3+1 tuning power supplies since 1984
Two groups of 2 cavities and one big group ( )
For RF manipulations voltage limited to 40 kV per group
Change tuning group configuration to
Adapt to present needs
60 kV per group
Below PS ring (inside)
Rewire 3 kA cables!

24. Rewiring 3 kA cables: before Connection box below C10-56
To C51
To C66
To C51
To C66
V. Desquiens
Connections to C56

25. Rewiring 3 kA cables: after Connection box below C10-56
To C51
To C66
To C51
To C66
V. Desquiens
Connections to C56

26. Frequency: Fixed tuning circuits (1984-2013)
Tuning-Groups:
hA: 36, 46
hB: 51, 56, 66, 76, 81, 91
hC: 86, 96
Group 4: 11, test cavity
→ All cavities of group tuned to same frequency
→ Hard-wired structure of tuning groups
→ 40 kV in three groups

27. Frequency: Fixed tuning circuits (2013-)
Tuning-Groups:
hA: 36, 46, 51
hB: 56, 66, 76, 81
hC: 86, 91, 96
Group 4: 11, test cavity
→ All cavities of group tuned to same frequency
→ Hard-wired structure of tuning groups
→ 60 kV in three groups

28. Tuning group change: status and consequences
Behavior of tuning groups verified before and after the change
First six cavities in the ring now pulsing
But:
All cavities in voltage program group should be in same tuning group
Now violated for almost all cycles
Need to adapt timing trees ( Steven’s presentation)
Need to rebuilt each cycle before it can be executed!
Major effort of reprogramming all RF functions
Please do not just put pre-LS1 cycles in the super-cycle!
Absolutely ‘non-transparent’

29. Overview Introduction Global beam control system modifications
RF systems for manipulations
Global beam control system modifications
Injection bucket control
RF controls renovation
10 MHz RF system
Voltage control and 1-turn delay feedback loops
Tuning group restructuring
10 MHz matrix control, spare cavity selection and linked timing
High-frequency and wide-band RF systems
20, 40, 80 MHz and 200 MHz
Wideband cavity for longitudinal damper
Summary

30. Voltage program generation: hardware matrix
Hardware matrix has served from the mid 1990’s until LS1
Complicated hardware with embedded micro-processor
6 analog functions + 12 timings in  11 analog function + 22 timings out
Pre-LS1
Functions and timings per group
Functions and timings per cavity
Few spare boards in unknown state left
Dangerous single point of failure

31. Voltage program generation Voltage programs to cavities:
Global program
Mapping from groups to cavities
voltage programs
gap relay timings
0…200 kV
Global red. ×
0…100%
Modifier grp. 1 ×
Modifier grp. 2 ×
Modifier grp. 3 ×
Modifier grp. 4 ×
Modifier grp. 5 ×
Modifier grp. 6 ×
0…100%
Voltage programs to cavities:
C11
C36
C46
C51
C56
C66
C76
C81
C86
C91
C96

32. New software based 10 MHz matrix
New implementation guidelines:
Distribution of digital voltage program data to each cavity
CVORB function generator channel and CTRV timings per cavity
No specific central hardware as single point of failure
Only simple electronics to distribute serial data streams
Move relevant parts of matrix to software  virtual matrix
Combine functions and restart timings to so-called real-time function per voltage program group
Copy real time functions per group to functions per cavity
Major implementation effort by P. Pera Mira and G. Kruk
H. D., S. Hancock, CERN-ATS-Note TECH

33. Real-time function generation
Voltage program modifier functions per group (with restarts) difficult to map
Calculate real-time functions PA.GS…RT, based on functions and timings
Copy only real-time (RT) functions to the functions per cavity
Function with restarts
Real-time function
( )
Functions per group drive no hardware anymore
Possibility to virtualize later

34. Voltage program generation Voltage programs to cavities:
Global program
Mapping from groups to cavities
voltage programs
gap relay timings
0…200 kV
Global red. ×
0…100%
Modifier grp. 1 ×
Modifier grp. 2 ×
Hardware switching of functions and timings migrated to software
InCA MakeRules to copy settings from groups to cavities
Integrated spare cavity selection mechanism for C11
Virtual matrix
Modifier grp. 3 ×
Modifier grp. 4 ×
Modifier grp. 5 ×
Modifier grp. 6 ×
Modifier grp. 7 ×
Modifier grp. 8 ×
0…100%
Voltage programs to cavities:
C11
C36
C46
C51
C56
C66
C76
C81
C86
C91
C96

35. Upgraded distribution of voltage programs
More flexibility thanks to renovated generation of voltage programs: so-called ‘matrix’
New hardware to generate digital voltage program data for each cavity
8 logical groups of cavities
Matrix functionality implemented in software
Commissioned and essentially ready for start-up

36. Application program New application (D. Cotte, R. Maillet)
Finally little changes from the operations point of view
Integrated spare cavity selection, also based on InCA MakeRules

37. Spare cavity selection Tuning group of cavity to be replaced by C11
Spare cavity C11 replaces any other 10 MHz cavity, needs:
Voltage program  like any other cavity
Harmonic number and relative phase  special
Previous implementation: hardware multiplexers for GFAS functions
MakeRules now copy relevant functions and timings on all LSA cycles
Tuning group of cavity to be replaced by C11
PA.GSHART
PA.GSRPART
PA.GSHBRT
PA.GSHDRT
PA.GSRPBRT
PA.GSRPDRT
A, B or C
A, B or C
PA.GSHCRT
PA.GSRPCRT
Harmonic
Relative phase
No dedicated hardware involved anymore
Flexible, could even drive C11 with its own functions and timings

38. Overview Introduction Global beam control system modifications
RF systems for manipulations
Global beam control system modifications
Injection bucket control
RF controls renovation
10 MHz RF system
Voltage control and 1-turn delay feedback loops
Tuning group restructuring
10 MHz matrix control, spare cavity selection and linked timing
High-frequency and wide-band RF systems
20, 40, 80 MHz and 200 MHz
Wideband cavity for longitudinal damper
Summary

39. Glue logic for the control: linked timing…
Pre-LS1
Timing tree structure assures coherence between harmonic number (tuning group) and voltage programs (matrix)
Old timing trees (LKTIM) incompatible with LTIM/CTRV timings
Migration of X-motif application to Java needed
New trees again with node and parent lists (Mbno  device ID)
Rules for timing and status calculation moved to InCA `

40. Glue logic for the control: linked timing
New application (D. Cotte, G. Kruk for the InCA part):
Little changes from the operations point of view
Comfortable handling of large timing trees, commissioning ongoing

41. Overview Introduction Global beam control system modifications
RF systems for manipulations
Global beam control system modifications
Injection bucket control
RF controls renovation
10 MHz RF system
Voltage control and 1-turn delay feedback loops
Tuning group restructuring
10 MHz matrix control, spare cavity selection and linked timing
High-frequency and wide-band RF systems
20, 40, 80 MHz and 200 MHz
Wideband cavity for longitudinal damper
Summary

42. Status of 20, 40, 80 and 200 MHz cavities
20 MHz cavities  As before LS1
40 MHz  C40-78 repaired, being commissioned
 Pre-driver amplifiers water-cooled
 Otherwise as before LS1
80 MHz cavities  Pre-driver amplifiers water-cooled
200 MHz cavities  Cavities as before LS1
 Renovation of C201/206 amplifiers
All high frequency cavities will be available for the start-up

43. Automatic tuning for 40 and 80 MHz systems
Keep cavities at fixed frequency
Microprocessor-based system after LS1
L. Arnaudon, S. Totos
Will also pilot switching of 80 MHz cavities for protons and ions
Commissioning during/after start-up

44. Renovation of 200 MHz amplifiers (C201/206)
New amplifiers in BA3 (SPS)
High power chain C202/C203/ C204/C205 completely renovated during the 2006/2007 shutdown
C201/206 followed during LS1
Before
Old amplifiers
New amplifiers
S. Rains, Ch. Renaud

45. Renovation of 200 MHz amplifiers (C201/206)
New amplifiers ready in building 151 (C201)
Amplifiers
Special old types irradicated
Interchangeable with SPS
Interlock system
More evolved then for C202-C205
Power supplies
Reliability
New amplifiers
C201/206 renovated for the start-up  all systems almost identical
Strategy for operation after LS1:
Run with four 200 MHz RF systems, including C201 and C206
Keep two cavities as hot spares

46. Overview Introduction Global beam control system modifications
RF systems for manipulations
Global beam control system modifications
Injection bucket control
RF controls renovation
10 MHz RF system
Voltage control and 1-turn delay feedback loops
Tuning group restructuring
10 MHz matrix control, spare cavity selection and linked timing
High-frequency and wide-band RF systems
20, 40, 80 MHz and 200 MHz
Wideband cavity for longitudinal damper
Summary

47. New cavity (#25) in the PS ring
Wide-band (0.4 – 5.5 MHz, VRF = 5 kV) cavity based on Finemet material
No acceleration, but damping of coupled-bunch oscillations
6-cell cavity unit
SS02
Accelerating gap
Power amplifiers (solid state)
M. Paoluzzi
Cavity installed in SS02, start with amplifiers on 2 gaps
First installation of transistor power amplifiers close to beam in PS

48. Coupled-bunch oscillation damping
Bunches oscillate with different phases (and amplitudes)
Example of an n = 12 mode (Df ≈ 206)
Mode number n defined by phase advance from bunch-to-bunch:
Df = 2p n/h
Kick
frf
Kicker baseband
Preferred detection
Measure
Coupled-bunch oscillations show up as side-bands of nfrev or (h-n)frev
Frequency range of new Finemet cavity allows to damp all modes
Commissioning after start-up

49. Overview Introduction Global beam control system modifications
RF systems for manipulations
Global beam control system modifications
Injection bucket control
RF controls renovation
10 MHz RF system
Voltage control and 1-turn delay feedback loops
Tuning group restructuring
10 MHz matrix control, spare cavity selection and linked timing
High-frequency and wide-band RF systems
20, 40, 80 MHz and 200 MHz
Wideband cavity for longitudinal damper
Summary

50. What to do will all this (new) stuff?
Summary
Extensive modifications to the PS RF systems during LS1
Most of them expected to be ‘transparent’, though the underlying design changes are significant
Tuning group change not transparent:
Rebuilt almost all cycles
Existing cycles must not be played without prior modifications!
Re-commissioning of RF systems progressing
Initial commissioning of new equipment, e.g., longitudinal damper will continue after start-up
What to do will all this (new) stuff?
Smooth start-up?
Smooth start-up!
Steven’s lecture on 10/04/2014

51. Thank you very much for your attention!