New PS one-turn delay feedbacks and further developments

Name: New PS one-turn delay feedbacks and further developments
Uploaded: 2017-08-25T05:12:24+00:00
Duration: PTM14S58
Channel: Lindsey Montgomery
Description: New PS one-turn delay feedbacks and further developments

New PS one-turn delay feedbacks and further developments
Damien Perrelet BE-RF-FB CERN LIU-DAY 2014, 11 April 2014 Thanks to Alfred Blas, Heiko Damerau, Valentin Desquiens, Simone Gilardoni, Guido Sterbini, Letizia Ventura, and all involved people from sections BE-RF-FB, IS and CS

Damien Perrelet BE-RF-FB CERN
Content Damien Perrelet BE-RF-FB CERN 19/04/2017 Overview of the new feedback board Current implementations: PS 10 MHz 1-turn feedback and AVC digital loops PS transverse damper Future developments: PS 1-turn feedback cavities 13/20/40/80 MHz PS longitudinal coupled-bunch feedback PSB/AD/LEIR transverse damper upgrade Summary and outlook 3/21/2014 Damien Perrelet BE-RF-FB CERN

The new hardware 3/21/2014 Damien Perrelet BE-RF-FB CERN

New PS feedback hardware
4 ADC RF INPUT CHANNELS → FPGA → DAC RF OUTPUT CHANNELS Power Combiner CLK DWSTR1 FPGA Stratix II EPS2S90F1020C4 Clock Distri NODLY d UPSTR d nUPSTR d DWSTR1 d DWSTR2 4 SERIAL LINKS VME + TRIGGERS ADC2 ADC1 ADC4 ADC3 LP DAC1 DAC2 DAC3 DAC4 ADCs AD6645 DACs AD9754 G Ctrl LMH6702 AD8009 Gap Return 1TFB TP DRIVE IN Vprog Test VPROG TP 50 MHz G Ctrl h200 CLK UPSTR Digital BP1 G Ctrl RF from BC AVC TP Power Combiner G Ctrl Spare VGAP DET TP 50 MHz CLK DWSTR2 SRAM 3/21/2014 Damien Perrelet BE-RF-FB CERN

Electronic board Generic VME board STRATIX II FPGA and external SRAM 4 RF channels ADC and DAC, low latency, 14 bits and running at 105/125 MSPS 2 multiplexed fine delay lines for glitch-free delay changes (DAC and FPGA clocking) 4 serial links CVORB or fast 40 Mbit/s 3/21/2014 Damien Perrelet BE-RF-FB CERN

PS 10 MHz loops 3/21/2014 Damien Perrelet BE-RF-FB CERN

PS 10 MHz cavity feedback overview
Final amplifier, MHz cavity, fast wideband FB H Gap return - Slow voltage control loop (AVC)  Gain control at fRF Reduction of cavity impedance seen by the beam: - Fast wide-band feedback around amplifier (internal)  Gain limited by delay - 1-turn delay feedback  High gain at n  frev Drive 1TFB DAC ADC AVC DAC ADC hn h200 Vprog RF from BC 3/21/2014 Damien Perrelet BE-RF-FB CERN

PS 1-turn delay feedback
3/21/2014 Damien Perrelet BE-RF-FB CERN

1-turn delay feedback Cascade of notch + comb
IIR fractional notch hn/hs Periodic comb at frev Cascade of notch + comb Suppress the RF component to not work against AVC High gain at frev multiples hn NOTCH FILTER COMB FILTER AUTO DELAY DAC ADC VGAP Detected 1TFB OUT to Drive FPGA VME INTERFACE d UPSTR d DWSTR RF CLK h200 NOTCH BYPASS VPROG DPRAM hn Fine delayed clock Unique sampling clock h200 integer multiple of the revolution frequency 8/4/2014 Damien Perrelet BE-RF-FB CERN

Measurements with beam before LS1
Spectrum at cavity gap voltage of a single high intensity bunch 8∙1012 ppb Filters only and closed loop transfer functions Beam induced spectrum of four bunches during batch compression 10 db/div h = 8 time FB off h = 8  13  20 10 db/div Feedback succesfully follows harmonic changes FB on time amplitude frequency frequency 3/21/2014 Damien Perrelet BE-RF-FB CERN

PS digital AVC loop 3/21/2014 Damien Perrelet BE-RF-FB CERN

AVC loop and AVC surveillance
RF from beam control Collaboration ADC RF-FB RF-IS RF veto Voltage program + Error[k] PID controller Drive DAC - Modulator Detected gap voltage Veto Power amplifiers hn CORDIC I Gap return non-IQ detection Cavity 10MHz Q ADC Amplitude loop only, future phase loop or move to IQ loop Voltage detection using non-IQ algorithm at given harmonic hn High power hardware safety ensured by separate surveillance module H. Damerau, V. Desquiens, M. Haase, D. Perrelet 3/21/2014 Damien Perrelet BE-RF-FB CERN

Digital AVC loop measurement
Step response of the controller around a cable 500 ms test pulse voltage program Response with fast voltage rise Vprog Vprog Vdet Error RF drive Vdet 15 turns Error Error 100 ms/div RF drive 10 ms/div Digital PID with adjustable parameters Regulation to full voltage without overshoot in about 15 turns 3/21/2014 Damien Perrelet BE-RF-FB CERN

Installation in the machine
Four new VME crates installed in building 359 (one for each tuning group) Example for tuning group B (cavities C56, C66, C76 and C81) Full commissioning of the new system during start-up 2014 3/21/2014 Damien Perrelet BE-RF-FB CERN

PS transverse damper 3/21/2014 Damien Perrelet BE-RF-FB CERN

PS transverse feedback
Firmware: A. Blas PU flight time compensation Periodic notch filter for orbit offset suppression Hilbert filter for phase compensation at betatron frequencies Automatic delay to complete 1 turn 3/21/2014 Damien Perrelet BE-RF-FB CERN

PS transverse feedback
See talk by Raymond Wasef Damper to cure horizontal and vertical transverse instabilities Damping of head-tail instability Damping of injection errors 10 ns/div PS TFB OFF 10 ns/div PS TFB ON → Present PS TFB designed to damp 44 μm/turn at 1.4 GeV (BW 23 MHz). A.Blas, S.Gilardoni, G.Sterbini 3/21/2014 Damien Perrelet BE-RF-FB CERN

New applications 3/21/2014 Damien Perrelet BE-RF-FB CERN

PS 1-turn feedbacks cavities 13/20/40/80 MHz
1) Analog conversion to IF and IQ digital processing → Using existing and analog frequency conversion boards or 2) Direct sampling → Modification of existing board to achieve higher sampling capabilities → Build a complete similar new and fast board Frequency conversion board Thomas Truszczyński Mini-PCB to fast ADC adaptation 3/21/2014 Damien Perrelet BE-RF-FB CERN

PS longitudinal coupled-bunch feedback
See talk by Letizia Ventura Cross-damping: hdet + hkick = hRF = 21 → Detect at h = 13 and Damp at h = 8 → Make a new digital coupled-bunch feedback for the Finemet cavity ADC DAC Beam (WCM) Longitudinal kicker (Finemet) H. Damerau, L. Ventura: Demonstrated with measurements using existing feedback and the spare cavity 3/21/2014 Damien Perrelet BE-RF-FB CERN

Future developments Target to other machines: Upgrade of PSB, AD and LEIR transverse dampers PS 10 MHz possible improvements: Cavity phase loop or IQ loop (Reliability of RF manipulations) Cavity phase compensation (More gain for 1-turn feedback) Multi-harmonic RF generation on-board and use of hs=256 3/21/2014 Damien Perrelet BE-RF-FB CERN

Summary and outlook Damien Perrelet BE-RF-FB CERN 19/04/2017 - New generic feedback board meets requirements → Complex design but easy to use and allows lots of features Two operational loops: PS 10 MHz 1-turn feedback and AVC → Fully digital and remote controlled → Commissioning during setting-up 2014 - New operational PS transverse damper → Good results and required for LIU beams - Many future developments and projects using this hardware → FPGA gives reliability and flexibility for new ideas 3/21/2014 Damien Perrelet BE-RF-FB CERN

Thanks for your attention
Many thanks to people from sections RF/FB-CS and RF/FB/IS for collaboration and support : Alfred Blas, Philippe Baudrenghien, Andy Butterworth, Heiko Damerau, Valentin Desquiens, Simone Gilardoni, Gregoire Hagmann, Matthias Haase, Wolfgang Hofle, Michael Jaussi, Gerd Kotzian, Tom Levens, Gérard Lobeau, John Molendijk, José Noirjean, Anthony Rey, Maarten Schokker, Guido Sterbini and Letizia Ventura. 3/21/2014 Damien Perrelet BE-RF-FB CERN

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