The TTF2 / VUV-FEL Linac RF Digital I/O Detection mixer RF 1300 MHz LO 1300.25 MHz IF 250 kHz time amlitude

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  • 04

    RF System

    Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 20

    The TTF2 / VUV-FEL Linac

    Outline

    • Overview of RF System • High Power RF - Klystron - Modulator - RF Waveguide Distribution

    • Low Level RF Control System - Configuration - Hardware - Software

    • Summary

  • Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 2004

    VUV-FEL RF System Diagram ACC1 ACC5 ACC4 ACC3 ACC2 ACC6 RF-Gun 3rd harm.

    Mod 4 (10 MW)

    Mod 5 (5 MW)

    Mod 6 (10 MW)

    Mod 7 (10 MW)

    SMES

    Mod 2 (5 MW) Mod 3 (5 MW)Mod 1 (5 MW)

    Teststand Hall 2

    For Test (Cavities, Couplers, Waveguides)

    2 x 5 MW

    3.3 MW3.3 MW3.3 MW

    3.3 MW 6.7 MW

  • Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 2004

    Klystrons • 5 MW Klystron THALES TH2104C • 10 MW Multi Beam Klystron THALES TH1801

    Operation Frequency: 1.3GHz Cathode Voltage: 117kV Beam Current: 131A Max. RF Peak Power: 10MW RF Pulse Duration: 1.5ms Repetition Rate: 10Hz

    The prototype has been in opera- tion at TTF since May 2000 and has 14000h operation hours

  • Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 2004

    Modulators The FNAL Modulators

    • 3 modulators delivered to TTF by FNAL since 1994

    • They are continuously in operation under different operation conditions

    • Comprehensive maintenance during shutdown, e.g. oil conditioning, cleaning and check of HV

    • Improvement of subsystems (e.g. HV switch, HVPS etc.) are continuing. They are ready for 10Hz operation

    The FNAL Modulators

  • Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 2004

    Modulators (2) Industry made Modulators(PPT Modulator)

    • 2 modulators are in operation, have now complete remote control and new RF interlocks (simpler version of the interlock under development)

    • Low leakage inductance pulse transformer (

  • Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 2004

    RF Power Waveguide Distribution • Distribution of klystron output power to the cavities • Protection of the klystron from reflected power • Control of phase and loaded Q

    ACC1 ACC3ACC2

    ACC4 ACC5

  • Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 2004

    Cavity Loaded Q and Phase Adjustment

    Motorized three stub waveguide tuners used to adjust phases and loaded Q for all cavities

    - Improvement from to30°± 3°±

  • Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 2004

    RF Control Requirements

    • Amplitude and Phase Stability:

    - amplitude

    - for phase (fast fluctuations)

    • Other requirements: - ACC1: cav. 1-4 at 12 MV/m, cav. 5-8 at 20 MV/m phase of accel- erating field -10.8 deg. - 3rd harmonic cavity at 14 MV/m at 183 deg. - S-Band cavity at 2856 MHz phase stability < 1 deg. - RF Gun operation without field probe. rep. rate, pulse length and power must be variable.

    σA A⁄ 10 4–<

    σϕ 0.1°<

    Gradient

    Power

    Detuning

    Time Phase

  • Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 2004

    RF Control Tasks List

    Cavities to be controlled:

    • RF gun

    • Vector-sum of cryomodule 1

    • 3rd harmonic cavity (3.9 GHz) (in 2006)

    • Vector-sum of cryomodules in locations 2+3

    • Vector-sum of cryomodules in locations 4+5+(6) (in 2006)

    • S-Band cavity at 2.856 GHz

    • Provide stable phase reference for laser, and diagnostics

  • Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 2004

    Schematic of the Digital RF System

    Tuner

    Cavity 1

    Directional CouplerForward

    Reflected RF

    RF

    RFLO

    LO

    LO

    DSP/FPGA DAC

    DAC

    I

    Q

    Tuner

    Cavity 8

    ...... 8x

    Tuner

    Cavity 9

    Tuner

    Cavity 16

    ...... 8x

    Cryomodule Cryomodule

    Klystron Circulator

    Power Transmission Line Power Transmission Line

    ADC

    ADC

    ADC

    V M E

    SUN

    Field Probe

    Incident Wave

    Reflected Wave

    Power

    Power

    fref = 9.02775 MHz ÷9

    flofrf

    frf = 144×fref ≅ 1300 MHz

    flo = (144+1/36)×fref ≅ 1300.25 MHz

    S&H

    -1

    Transient Detection

    I/Q

    Vector Modulator

    I Q

    Waveguide Tuner

    1 MHz Clock

    200kW

    4×8 channel ADC board 14 bit @ 1 MHz

    250 kHz

    ADC

    ADC

    ADC

  • Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 2004

    Digital I/O Detection

    mixer

    RF

    1300 MHz LO

    1300.25 MHz

    IF 250 kHz

    time

    amlitude

    • downconversion of cavity field to IF frequency at 250 kHz

    • complete phase and amplitude information of the accelerating field is preserved.

    • sample IF signal at 1MHz rate • subsequent samples describe

    real and imaginary component of the cavity field.

    t0 t1 t2 t3

    x0 x1

    x2 x3

  • Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 2004

    Control Algorithm D

    A C

    D A

    C

    ReIm

    Cavity 32 ...... 8x

    Cavity 25

    klystron vector

    modulator master oscillator

    1.3 GHz Cavity 8 ...... 8x

    Cavity 1

    cryomodule 4

    ... cryomodule 1

    . . . . LO 1.3 GHz

    + 250 kHz 250 kHz

    AD C

    f = 1 MHz s

    . . . . ...

    vector-sumΣ ( )aba -b 1 8( )ab

    a -b

    25 ( )aba -b 32( )ab

    a -b

    DSP systemsetpointtable

    gain table

    feed

    table forward

    ++ digital

    low pass filter

    ImRe ImRe ImRe

    clock

    LO

    AD C

    LO

    AD C

    LO

    AD C

    ImRe

    power transmission line

    1.3GHz field probe

  • 04

    ware

    annels for the control

    Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 20

    Digital Feedback Hard • DSP System - New hardware, faster DSPs (C67), input ch

    of 8/16/24 cavities - 8 channel ADC board - 8 channel DAC board - Gigalink interface between boards

  • Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 2004

    Digital Feedback Hardware (2)

    • Downconverter based on AD 8343 • RF Gun detectors (forward and reflected power) - AD8347 IQ demodulator (for feedback) - Schotty diode for amplitude (redundant) - HMC precision phase detector (redundant) - AD 8302 for cavity detuning

    Gun Control BoxDownconverters

  • Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 2004

    Digital Feedback Hardware (3)

    Gun and ACC1 ACC2, ACC3, ACC4 & ACC5

  • 04

    ware

    oint, feedback gain and

    face

    rement, Loaded Q and

    Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 20

    Digital Feedback Soft

    • DSP System - Exception detection and handling

    • DOOCS DSP Server - Parameter based operation, tables for setp

    feedforward calculated by server

    • DOOCS Finite State Machine Server - Automated operation, Simple operator inter

    • Application tools - Adaptive feedforward, Beam phase measu cavity detuning measurement...

  • Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 2004

    0.02

    0.04

    0.06

    0.08

    30

    210

    60

    240

    90

    270

    120

    300

    150

    330

    180 0

    Module 1 (ACC1*)

    12345 678

    0.02

    0.04

    0.06

    30

    210

    60

    240

    90

    270

    120

    300

    150

    330

    180 0

    Module 1 (ACC1*)

    1

    2

    3 4

    56 7

    8

    0.02

    0.04

    0.06

    30

    210

    60

    240

    90

    270

    120

    300

    150

    330

    180 0

    Module 1 (ACC1*)

    1

    2 34

    5

    67 8

    Beam Based Calibration - Good beam required to get sufficient signal (8nC, 30µs, 15MV/m) - Preliminary calibration (to 10%) - Gradient calibration (to 3-5%)

  • Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 2004

    Exception Handling - Cavity quench detection mechanism (algorithms) - Exception handling procedure

    Module 1* at high gradient 1-st quench in Cavity 2 2-nd quench in Cavity 6 3-rd quench in Cavity 1 Eacc=19[MV/m] Eacc=21[MV/m] Eacc=24[MV/m]

  • Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 2004

    Automation of RF Operation

    - High degree automation of accelerator operation - Reduce workload of operators - Maximize availability of accelerator

    Check/reset interlocks, Find source, check limits...

    Adjust feedback loop,

    Optimize beam parameters

    High voltage is applied,

    RF is not permitted

    RF_ON

    RF_STDBY

    HV_ON

    Start-up procedure IDLE

    Graphical representation of logical dependencies

  • Ayvazyan / Simrock, DESY MAC Meeting, Nov. 9th 2004

    Master Oscillator and Frequency Distribution System

    • Master Oscillator: - Required frequencies: 50Hz, 1MHz, 9MHz, 13.5 MHz, 27MHz, 81MHz, 108