Ron Akre, Dayle Kotturi LCLS LLRF [email protected]@slac.stanford.edu, [email protected]@slac.stanford.edu September 19, 2006

Ron Akre, Dayle Kotturi

LCLS LLRF Review [email protected], [email protected]

September 19, 2006

Linac Coherent Light Source (LCLS)

Low Level RF System

Injector Turn-on January 2007

September 19, 2006



September 19, 2006

Safety First and Second and Third…..to Infinity

Hazards in the LLRF systemRF 1kW at 120Hz at 5uS = 0.6 Watts average, 2 Watt average amps at 2856MHz, 60W average amps at 476MHz

Hazards – RF BurnsMitigation – Avoid contact with center conductor of energized connectors. All employees working with LLRF systems are required to have the proper training.

110VAC ConnectorHazards - Shock Mitigation - Don’t touch conductors when plugging into outlet.All chassis are inspected by UL trained inspector.



September 19, 2006

Scope of Work – Injector Turn-onLinac Sector 0 RF Upgrade

All 3 RF Chassis completed and Installed (Master Oscillator, Master Amp, PEP phase ShifterControl Module ready for test – higher phase noise levels if not installed

Sector 20 RF distribution systemPhase and Amplitude Controllers (PACs) – 6 unitsPhase and Amplitude Detectors (PAD) – 2 unitsPhased Locked Oscillator – Use SPPS unit for Turn OnLO Generator – Complete - 50% tested – looks good so farMultiplier – 476MHz to 2856MHz – Complete 50% Tested4 distribution chassis – Complete 102MHz, 2056MHz, 2830.5MHzLaser Phase Measurement – in Design, diagnostic, not required for turn on – Laser group wants it next week. Distribution Amplifiers – 10W, 2850MHz on order – 10W, 102MHz Amp in search Minicircuits has 5W and 50W

LLRF Control and Monitor System1 kW Solid State S-Band Amplifiers – 5 units – Design Complete, In FabPAD – 12 units – 6 required for turn on PAC – 6 unitsBunch Length Monitor Interface – awaiting Specs

Beam Phase CavityWill use single channel of PAD ChassisPill box cavity with 2 probes and 4 tuners – 2805MHz 3 units Complete



September 19, 2006

LCLS Layout

P. Emma



September 19, 2006

LLRF Control system spans Sector 20 off axis injector to beyond Sector 30



September 19, 2006

LCLS RF Jitter Tolerance BudgetLCLS RF Jitter Tolerance Budget

RMS tolerance budget for <12% rms peak-current jitter or

<0.1% rms final e− energy jitter. All tolerances are rms levels and the voltage and

phase tolerances per klystron for L2 and L3 are Nk larger,

assuming uncorrelated errors, where Nk is the number of

klystrons per linac.

P. Emma

Lowest Noise Floor Requirement 0.5deg X-Band = 125fSStructure Fill time = 100nSNoise floor = -111dBc/Hz @ 11GHz 10MHz BW-134dBc/Hz @ 476MHz

X-bandX-band XX--

0.500.50



September 19, 2006

Slow Drift Tolerance LimitsSlow Drift Tolerance Limits

Gun-Laser TimingGun-Laser Timing 2.4*2.4* deg-Sdeg-S

Bunch ChargeBunch Charge 3.23.2 %%

Gun RF PhaseGun RF Phase 2.32.3 deg-Sdeg-S

Gun Relative VoltageGun Relative Voltage 0.60.6 %%

L0,1,X,2,3 RF Phase (approx.)L0,1,X,2,3 RF Phase (approx.) 55 deg-Sdeg-S

L0,1,X,2,3 RF Voltage (approx.)L0,1,X,2,3 RF Voltage (approx.) 55 %%

(Top 4 rows for (Top 4 rows for // < 5%, bottom 4 limited by feedback dynamic range) < 5%, bottom 4 limited by feedback dynamic range)

* for synchronization, this tolerance might be set to * for synchronization, this tolerance might be set to 1 ps (without arrival-time measurement)1 ps (without arrival-time measurement)

(Tolerances are peak values, not rms)(Tolerances are peak values, not rms) P. Emma, J, WuP. Emma, J, Wu



September 19, 2006

Distribution system



September 19, 2006

Concerns of Previous ReviewsInstallation of temperature stabilized cables can effect phase stability.

Working with cable shop on plan for installationTriggers required to be synchronous with 476MHz may jitter

The highest frequency that triggers need to be synchronous with is 102MHz. Procedurally triggers will be placed in the stable region

SPPS PLL design generates an internal pulse width based on a one-shot and uses an old track and hold chip

Redesign of this chassis will be done next year and these comments will be taken into consideration

LO Generator design uses internal trim caps and resistors to calibrate unit, synchronization needs to be addressed, should consider SSB modulator

We are using internal trim caps and resistors - have not had a problem in the past with these types of devicesThe synchronization will be monitored and can be reset if it gets out of syncThe unit is a SSB modulator

Concerns of Hardware and Software being disconnected from each other and the review committee would also like to better understand the software.

The LLRF Hardware effort has been moved to the controls group and is now being reviewed with the software.



September 19, 2006

Linac Sector 0 RF Upgrade

PEP PHASE SHIFT ON MAIN DRIVE LINE MDL RF with TIMING Pulse – Sync to DR

Master Oscillator is located 1.3 miles

from LCLS Injector

1.3 Miles to LCLS Injector

LCLS must be compatible with the existing linac operation including PEP timing shifts

MASTERAMPLIFIERS

MAIN LINAC (SECTOR 0) RF/TIMING SYSTEM

1

476MHzMASTEROSCILLATOR

PEP PHASESHIFTER+-720 Degreesin 0.5mS

SLC COUNTDOWNCHASSIS 476MHzDivide to 8.5MHz

Master TriggerGenerator MTGSyncs Fiducial to8.5MHz Damping Ringand 360Hz Power Line

8.5MHz

360Hz LineSync.

476MHz

360Hz

Fiducial GeneratorSyncronized to:360Hz Power Line8.5MHz Damping Ring476MHz RF Distribution

SumFiducialto RF

Main Drive Line (MDL)476MHz RF plus360Hz FiducialTo:Main Linac - 2 milesDamping RingsPEPNLCTAEnd Station AFFTBORION

Measurements on January 20, 2006at Sector 21show 30fS rms jitter in a bandwidth from 10Hz to 10MHz



September 19, 2006

PEP II Phase Shifter10kHz freq shift 1.2Vpp IQ in

Agilent E4407B

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

10

20

475950000 475970000 475990000 476010000 476030000 476050000

Frequency

dB

m



September 19, 2006

Linac Sector 0 RF Upgrade Status

New Low Noise Master Oscillator – Done

New Low Noise PEP Phase ShifterRF Chassis – Done

Control Chassis – Ready for installation

New Low Noise Master Amplifier – Done

Main Drive Line Coupler in Sector 21 – Done

Measurements Noise floor on 476MHz of -156dBc/Hz

Integrated jitter from 10Hz to 10MHz of 30fS



September 19, 2006

RF System Topology / Specifications

476MHz PLL2830.5MHz LOAmp / Splitter

Laser

RF Gun

L0A

Phase Cavity

L0B

L1S

L1X

L2 Ref

PAD

Laser

RF Gun

L0A

Phase Cavity

L0B

L1S

L1X

L2 Ref

Most Devicesare in tunnel

Laser

RF Gun

L0A

Phase Cavity

L0B

L1S

L1X

L2 Ref

1

Number of cables per deviceReference cables are8ft and can drift +-50fS

1

2

4

2

2

2

5

RF HUT

+-240fS

+-310fS

+-370fS

+-680fS

+-500fS

+-160fS

+-140fS

+-240fS

Cable Drift Based onTemperature variationsand temp co of 5ppm/degC

LinacSector 0 RF

MDL

L2 - 4 SectorsSpecifications70fS rms jitter+-5pS drift


L0, L1 - 5 KlystronsSpecifications100fS rms jitter+-2.3pS drift



September 19, 2006

Sector 20 RF Distribution

RF CONTROLSPAC

380-208-22476MHz to 2856MHzMULTIPLIER

2830.5MHz LO Gen

RF MONITORPAD

119MHz Phase

119MHz

Main Drive Line (MDL)476MHz RF360Hz FiducialFrom Sector 0 (2km)

RF HUT Coupler476MHz Ref. 80uW

LASERReference

4x 476MHz13dBm OUT

ExistingTIMING SYSTEMFIDO Output

LCLS 476MHz PLL120HzTRBR

LCLS Sector 20 RF Reference System

+13dBm in

Track/HoldTRBR

2856MHz16 Way Distribution20dBm each

GunL0AL0BL0TCAVL1SL1X

+17dBm out

2856MHz2Watt Amplifier

102MHzDigitizer Clocks16 Way Distribution26dBm each

Diode Detector

476MHzLASER LOCKReference

119MHz0dBm OUT

LO Phase Monitor

102MHz2Watt Amplifier

RF MONITOR PAD

RF CONTROLSPAC

GunL0AL0BL0TCAVL1SL1XLINACEXPERIMENTS

Sample and Hold PLLwith DAC offset adjustand Error Monitor

RF CONTROLSPAC

2830.5MHz2Watt Amplifier

380-208-22476MHz to 2856MHzMULTIPLIER

2830.5MHz LO16 Way Distribution20dBm each

2856MHz in

IQ Modulator to adjust2830.5MHz to 2856MHz Phase

Divide 112 to 25.5MHzSSB Mix to 2830.5MHz4X to 102MHz

25.5MHz out

102MHz out 2830.5MHz out

Diode Detector

RF CONTROLSPAC

GunL0AL0BL0TCAVL1SL1X

Diode Detector

+13dBm in

LO Phase Monitor

LO Phase Monitor

RF CONTROLSPAC

RF MONITORPAD

+17dBm out

RF MONITOR PAD

MDL to Linac Sectors 21 to 30PEP and Research Yard

FSJ4-50 0.8dB/30ft

2856MHz from Sector 21

LCLS LLRF 476MHz Linac Ref.

4 x +13dBm out

380-208-38476MHz Amp30dB Gain 19dBm

LASER DiodeMeasurement

Phase Noise and Timing

2856MHz and 119MHz

LASER DiodeOutput

LO Phase MonitorRF MONITOR PAD

RF MONITOR PADLO Phase Monitor

LO and 102MHz resync by adjusting 2856MHz PAC while monitoring S21 2856MHz

Laser resync with laser PAC while monitoring difference in 119MHz laser and FIDO out



September 19, 2006

2830.5MHz Generator

B. Hong



September 19, 2006

Phase Noise Measurements

By J. Frisch

Noise Floors Lower Than

Expected Values which are

Lower than Requirements



September 19, 2006

Sector 20 RF Distribution System StatusPhase Locked Oscillator – 476MHz – Done for now

Initial Turn On use SPPS OscillatorWill modify control to achieve better stability during 2007

LO Generator – 2830.5MHz - Built – 50% testedMultipliers - 476MHz to 2856MHz – Built – 50% testedPhase and Amplitude Control (PAC) Unit

See next section

Phase and Amplitude Detector (PAD) UnitSee next section

Distribution Amplifiers 2850MHz due mid October102MHz search under way

Laser Phase Measurement SystemMay design DC PAD control board



September 19, 2006

LLRF Distribution Schedule

Racks to be installed in RF Hut – next week

RF Cables (On-site) to be pulled – mid October

RF Chassis – 50% complete10 more chassis required for turn on, to be installed by December

Remainder by March 2007

Testing of RF distribution system - DecemberPhase measurements of cables / looped

Ready for turn-on – Mid December



September 19, 2006

Beam Phase Cavity Status

Electronics will use single channel of PAD ChassisPill box cavity with 2 probes and 4 tuners Cavity Electronics will use single channel of RF MonitorThree cavities fabricated

The cavity was moved to 2805MHz after concerns of the last review about Dark Current were analyzed. Measurement of beam phase to RF reference phase. The result will be used to correct timing of laser to RF reference. 2805MHz cavity is located between L0A and L0B. Will use RF PAD with 2830.5MHz LO for a 25.5MHz IF.



September 19, 2006

LLRF Control System

Distributed Control System

Microcontroller based IOC Control (PAC) and Detector (PAD) Modules

Ethernet Switch

Central Feedback Computer



September 19, 2006

Concerns of Previous Reviews

The Slow ADC can have problems with ground noise and should be mounted on the RF board.

The Slow ADC is mounted on a separate board for the PAD and the same board for the PAC. It is used to monitor various devices including external thermocouples, RF power levels, and power supply voltages.

The system is being designed with too little diagnostics, at a minimum the input power should be monitored for remote chassis.

The PAC is being designed with a monitor for input power. The LO on the PAD, when used, will also be monitored.

The PAD and PAC systems should report missing, unexpected or multiple trigger signals remotely.

The PAC currently has the ability to report missing triggers, but the features have not yet been tested. The processor on the PAD has the capability to do this also and this will be considered in the future if thought necessary.



September 19, 2006

LLRF Control and Monitor System Klystron Station

13dBm

17dBm

SPARE

KLYSTRON STATION

21dBm

240ft = 17dB 1/2 Superflex= 10dB LDF4

240ft = 2.5dB 1/2 Superflex= 1.6dB LDF4= 3dB LDF1

3dBm

3dBm

140ft = 25dB 3/8 Superflex

Coupled Out

ENET

TRIG

TRIG

ENET

GATEfromBCS

GATE

LCLS RF HUT2830.5MHz LOAmp / Splitter

TCAV

RF Gun

L0A

L0B

L1S

L1X

RF HUT

PAC

20-5

20-6

20-7

20-8

21-1

21-2

LCLS RF HUT2856MHz RFAmp / Splitter

TCAV

RF Gun

L0A

L0B

L1S

L1X

20-5

20-6

20-7

20-8

21-1

21-2

LCLS RF HUT102MHz ClockAmp / Splitter

TCAV

RF Gun

L0A

L0B

L1S

L1X

20-5

20-6

20-7

20-8

21-1

21-2

PAD

In 2856MHz Out

102MHz Clock In

Trig & Ethernet

SSSB

102MHzClock In Out

LO

Trig & Ethernet

To IPAKlystron Drive

In 2856MHz Out

SSSB Control Control & Monitor

From Klystron Drive Coupler

KLY BEAM Voltage

PAC OUT

Coupled Out



September 19, 2006

RF & Temperature Signal Counts for FeedBack exclude Klystron PADs

ADC Chan Cnt/FBK Hut PADs Temp. Mon.

Distribution/Laser 7/0 1.5 6RF Gun 6/5 1.5 6Beam Phase Cavity 2/1 0.5 3L0-A Accelerator 2/2 0.5 3L0-B Accelerator 2/2 0.5 3L0-T Transverse Accelerator 2/0 0.5 3L1-S Station 21-1 B, C, and D Acc 4/4 1.0 6L1-X X-Band accelerator X-Band 2/2 0.5 3S25-Tcav 2/0 0.5 3S24-1, 2, & 3 Feedback 0S29 and S30 Feedback 0



September 19, 2006

LLRF Control and Monitor System Status

1 kW Solid State S-Band Amplifiers – 5 units1kW amplifier modules currently in test

Existing amplifier support design under review

Phase and Amplitude Detectors – 11 quad chan unitsControl Board – Pre production delivered – may require 2nd round.

RF Board – in layout

Phase and Amplitude Controllers – 6 unitsControl board – Sent out for Pre production

RF Board – Pre-production in Fab.



September 19, 2006

PAD



September 19, 2006

PAD Block Diagram

Chan. 0

4 X 16 bit ADC102MHz ClockLTC2208Transformer Coupled Inputs

Chan. 1

WCLK

FIFO 64k words

16bit DATA

WCLK

CHAN 1RF INPUTRP N

CHAN 0RF INPUTRP N

16bit DATA

MIXER

LORF

IF

Control

Control Board

RF Board

FIFO 64k words

FIFO 64k words

FIFO 64k wordsWCLK

16bit DATA

WCLK

16bit DATA

CO

MR

AW

ETH

ER

NE

T

Chan. 3

Chan. 2

QSPI

5VDC0.5A Digital

5VDC0.8A x 2 Analog

LO OUTPUT2830.5MHzRP N

24Bit Analog InputBoard

QSPI

20 pin ribbonTRIG MonFP BNC

ANALOG IN ANALOG IN

CLOCK Mon102MHzFP N

CLOCK IN102MHzRP N

TRIG In120HzRP BNC

CS/CLK

16 bitDATA

CONTROL /Arcturus uC5282Microcontroller Modulewith 10/100 Ethernet

ETH

ER

NE

T

CPLD

10dBm

FILTER 25.5MHz BP

CPL7

CHAN 125.5MHz IFFP BNC

MIXER

LORF

IF

FILTER 25.5MHz BP

LO INPUT2830.5MHzRP N

LO DIODEDETECTORFP BNC

CHAN 1TEST PORTFP N

CHAN 0TEST PORTFP N


CHAN 0TEST PORTRP SMA

CHAN 2RF INPUTRP N


CHAN 3RF INPUTRP N

MIXER

LORF

IF

RF Board

LO OUTPUT2830.5MHzRP N

FILTER 25.5MHz BP

CPL7


MIXER

LORF

IF

FILTER 25.5MHz BP

LO INPUT2830.5MHzRP N

LO DIODEDETECTORFP BNC

CHAN 3TEST PORTFP N

CHAN 2TEST PORTFP N




Most PADs will consist of 2 RF Modules to down convert 2856MHz to 25.5MHz, a 4 Channel, 16bit, digitizer control board, and an 8 channel 24bit slow analog input.

RF Board Mixers Marki Microwave M1-2040MEZ : Amplifiers Sirenza SBW-5089 : Slow ADC TI/BB ADS1218 : Fast ADC LT LTC2208



September 19, 2006

PAD RF Power Levels # ADCs RF Power

PAD PowerDistribution 4 10mW-100mWRF Gun Forward 1 10MW 10W-30WRF Gun Probes 4 10MW 10W-30WBeam Phase Cavity 2 100mW 30mWL0-A Accelerator 2 60MW 120WL0-B Accelerator 2 60MW 120WL0-T Transverse Accelerator 2 0.5MW 0.5W-30WL1-S Station 21-1 B, C, and D Acc 4 15MW 30W-120WL1-X X-Band accelerator X-Band 2 20MW 2WS25-Tcav 2 10MW 10WS24-1, 2, & 3 Feedback 0S29 and S30 Feedback 0



September 19, 2006

PAD 4 Chan ADC Board25.5MHz 4 point IQ Data Analysis – SNR – 76dB Amplitude 76dB Phase

Noise Floor from below plots < -147dBc/Hz - SNR 65dB

25.5MHz Cross Talk from below plots < 100dB

Channel 0 data: Signal = -7.1dB Noise Level = -72.1dBChannel 1 data: Signal = -112dB Noise Level = -79.3dB

Bin Width 1816Hz, 33dB



September 19, 2006

PAD Software

Different LLRF apps need different calculationsThere are 5 different algorithms:

AVG+STD – calculate average I and Q and variance of I and QRF WF – calculate average I and QWF – calculate average of sampleRF WF2 – calculate average I and Q of two samplesIQ Cal – send 64K raw data waveform

Each channel on a PAD can run a different algorithmEach PAD can run in CALIBRATION or RUNNING mode, which use different algorithms



September 19, 2006

PAD Software

Data acquisition begins via timing trigger

Each PAD needs its own trigger so that it can have its own delay

4 channels of 1024 16-bit integers at 102 MHz read in within 2 ms



September 19, 2006

PAC



September 19, 2006

PAC Block Diagram

Amp

SSSBChassisRP 15 Pin D

RA

WE

THE

RN

ET

CO

M

AmpMAX58752 X 16 bit DAC119MHz Clock(1MHz to 200MHz)

I

RF LO

Q

I&Q MODULATOR

1

2

3

4

Q

I XILINXSPARTAN 3FPGA

16bit DATA

CS/CLK

16bit DATA

16 bitDATA

CLK

CLK CONTROL /Arcturus uC5282Microcontroller Modulewith 10/100 Ethernet

ETH

ER

NE

T

Control

RF OUTPUTTo SSSBRP N

Control

TRIGGERMonitor TTLFP BNC

MATCHINGFILTERNETWORK

EXT TRIG120HzRP BNC

2856MHzRef InRP N

I MONITORFP BNC

RF OUTPUTMonitorFP N

RF INPUTMonitorFP N

NC

Q MONITORFP BNC

RF INPUTMonitor DiodeFP BNC

AD8099 Diff Amp

SSSBTrigTTL17 to 30uS

SSSBGate MonitorFP BNC

J4

H12

H10H9

J5

H7 J3J2 P5H6

CLOCK119MHzRP N

RF Module

t

TemperatureMonitor


t

Control Board

TemperatureMonitor

SLOW ADCsPAC TempIQ TempSSSB TempSSSB P-FWDSSSB P-RFLSSSB PWR+5V-12V



September 19, 2006

PAC SSB Modulator Tests

PAC SSB Modulator TestsSN 3 May 5, 2006

-120

-110

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

475400000 475600000 475800000 476000000 476200000 476400000 476600000

Frequency

dB

m

58kHz lower side band test – Suppression of fundamental and opposite side band is better than 60dB.



September 19, 2006

PAC Software

PACs can run in either CALIBRATING or RUNNING mode. A state machine keeps track.

If CALIBRATING, calibration waveforms are loaded into FPGA and I and Q gains and offsets can be adjusted.

If RUNNING, I and Q gains and offsets are fixed, operational waveforms are loaded into FPGA and I and Q adjustments can be applied at the operational frequency.



September 19, 2006

VME



September 19, 2006

VME Software

Generic Feedback algorithm:Phase and amplitude are calculated from I and Q averages from each channel of the PADPhases are corrected by phase offset correctionAmplitudes are corrected by amplitude power correctionPhase and amplitudes are weighted by configurable weighting factors to determine one average phase and amplitudeLocal or global feedback corrections are appliedCorrected phase and amplitude is converted to I and QCorrected I and Q values are sent to PAC



September 19, 2006

VME SoftwareBeam Phasing Cavity algorithm (for Laser Timing):

Two sets of I and Q averages arrive (since there are two windows of interest)Phase1 is calculated from I1 and Q1Phase2 is calculated from I2 and Q2Measured beam phase is the y-intercept of the equation to the line of phase as a function of FIFO positionFrequency is the slope of the line Amplitude is calculated from I1 and Q1 (only)Phase is corrected by phase offset correctionAmplitude is corrected by amplitude power correctionLocal feedback corrections are appliedCorrected phase and amplitude is converted to I and QCorrected I and Q values are sent to laser PAC



September 19, 2006

VME Software

Other calculationsFor RF Reference Distribution

Phase and amplitude are calculated from I and Q averages from each channel of the PAD

Phases are corrected by phase offset correction

Amplitudes are corrected by amplitude power correction

Standard deviation of I and Q is calculated from I and Q variances from each channel of the PAD



September 19, 2006

Linac Station 21-1 Tests



September 19, 2006

Linac 21-1 Test Set-up

Linac Ref Amp

MDL

6x Multiplier 2830.5MHzGenerator

PAC

102MHz 2830.5MHz

PADCLK LO

CLK OUT

CLK

SSSB

ExistingIPA

5045 KLYSTRON

RF

IN1

RF

OU

T2

KlystronForward RF

Accelerator x3

SLED

New Equipment AddedFor Tests

Power Coupled out from 476MHz MDL drives a 476MHz Amplifier which feeds a 6X Multiplier from 476MHz to 2856MHz.

The 2856MHz out drives both the LO generator and the PAC.

The 2830.5MHz LO and 102MHz CLK Generator supplies the LO and CLK to the PAD. A CLK output of the PAD drives the PAC CLK.

The PAC output drives the SSSB.

The SSSB drives the existing IPA chassis

The klystron output coupler is used to measure phase and amplitude with the new PAD.



September 19, 2006

Linac 21-1 Test ResultsTests were done in the gallery with no temperature regulation on cables. Average RMS value of 2 second sliding average is 0.068 degrees.

Exponential Smoothing Yields the Following Results. Lowest noise is with a time constant of about 2 points.



September 19, 2006

END of TALK



September 19, 2006

EPICS PANELS

Single Pulse Diagnostic Panels for PADs are RunningRemaining Software

History Buffer Select PVsMulti pulse data analysis, correlation plotsLocal RF Feedback loopsLinks to global Feedback loops



September 19, 2006

End of LLRF RF TalkBackup for RF Talk

Mostly Correct



September 19, 2006

DESIGN PHILOSOPHY

Reliability is inversely proportional to the number of connectors.

Stability is inversely proportional to the number of connectors.

Measurement accuracy is inversely proportional to the number of connectors and the amount of Teflon, which is typically found in connectors.

Cost of maintenance is proportional to the number of connectors.



September 19, 2006

Electro-Optical SamplingElectro-Optical Sampling

170 fs rms170 fs rms

Single-ShotSingle-Shot

Timing JitterTiming Jitter(20 Shots)(20 Shots)

200 200 m thick ZnTe crystalm thick ZnTe crystal

ee

Ti:Sapphire Ti:Sapphire laserlaser

Adrian Cavalieri et al., Adrian Cavalieri et al., U. Mich.U. Mich.

<300 fs<300 fs

ee temporal information is encoded on temporal information is encoded on transverse profile of laser beamtransverse profile of laser beam



September 19, 2006

MPS – PPS Issues Addressed by Controls Group

Not Reviewed Here Vacuum

New vacuum system summary to be fed to each klystron existing MKSU.

PPS SystemInjector modulators will be interlocked by Injector PPS system.PPS requirements for radiation from the injector transverse accelerator needs to be determined. Radiation levels will be measured during testing in the Klystron Test Lab – Feb 06.



September 19, 2006

Bandwidth of S-Band System

Upper Frequency Limit – 10MHzBeam-RF interaction BW due to structure fill time

< 1.5MHz S-Band Accelerators and Gun

~10MHz X-Band and S-Band T Cav

Structure RF Bandwidth ~ 16MHz

5045 Klystron ~ 10MHz

Lower Frequency Limit – 10kHzFill time of SLED Cavity = 3.5uS about 100kHz

Laser – Needs to be measured ~ 10kHz



September 19, 2006

Noise LevelsRF Reference Single Side Band (SSB) Noise Floor

2856MHz RF Distribution -144dBc/Hz-174dBc/Hz @ 119MHz (24x = +28dB +2 for multiplier)

2830.5MHz Local Oscillator -138dBc/Hz

Integrated Noise-138dBc/Hz at 10MHz = -65dBc = 32fS rmsSNR = 65dB for phase noise

Added noise from MIXER (LO noise same as RF)SNR of 62dB

ADC noise levelsSNR of 70dB – 14bit ADS5500 at 102MSPS



September 19, 2006

Phase Noise – Linac Sector 0

OLD MASTER OSCILLATOR-133dBc/Hz at 476MHz 340fSrms jitter in 10MHz BW

NEW MASTER OSCILLATOR-153dBc/Hz at 476 MHz34fSrms jitter in 10MHz BW

Integrated Noise - Timing Jitter fs rmsIntegral end 5MHz 10kHzIntegral start 1M 100k 10k 1k 100 10Aug 17, 2004Sector 30 27 30 33 38 75 82Jan 20, 2006Sector 21 15 19 20 20 8 17



September 19, 2006

Sector 20 RF Distribution Cable ErrorsTemperature Coefficient of 2.8ppm/ºF and Cable length is 1200ºS/ftAll Cables except LASER are less than 100ft

Distances feet and errors in degrees S total range

RF Hut Down Linac Wall Injector TotalUnit Ft degS ft degS ft degS ft degS ft degS DegSLaser 8 0.054 25 0.017 10 0.014 10 0.007 85 0.58 0.68Gun 8 0.054 25 0.017 10 0.014 10 0.007 40 0.27 0.37L0-A 8 0.054 25 0.017 10 0.014 10 0.007 30 0.21 0.31B Phas 8 0.054 25 0.017 10 0.014 10 0.007 20 0.14 0.24L0-B 8 0.054 25 0.017 10 0.014 10 0.007 20 0.14 0.24L0-T 8 0.054 25 0.017 10 0.014 10 0.007 10 0.07 0.17L1-S 8 0.054 25 0.017 50 0.068 0.14L1-X 8 0.054 25 0.017 60 0.081 0.16Temperature Variations: RF Hut ±1ºF : Penetration ±0.1ºF : Linac : ±0.2ºF

Shield Wall ±0.1ºF : Injector ±1ºF



September 19, 2006

RF System Topology / Specifications

476MHz PLL2830.5MHz LOAmp / Splitter

Laser

RF Gun

L0A

Phase Cavity

L0B

L1S

L1X

L2 Ref

PAD

Laser

RF Gun

L0A

Phase Cavity

L0B

L1S

L1X

L2 Ref

Most Devicesare in tunnel

Laser

RF Gun

L0A

Phase Cavity

L0B

L1S

L1X

L2 Ref

1

Number of cables per deviceReference cables are8ft and can drift +-50fS

1

2

4

2

2

2

5

RF HUT

+-240fS

+-310fS

+-370fS

+-680fS

+-500fS

+-160fS

+-140fS

+-240fS

Cable Drift Based onTemperature variationsand temp co of 5ppm/degC

LinacSector 0 RF

MDL



L0, L1 - 5 KlystronsSpecifications100fS rms jitter+-2.3pS drift



September 19, 2006

RF Monitor Signal CountsADC Chan Cnt Chassis

Count/LocationDistribution (5~2850MHz, 4<500MHz) 4 1HutRF Gun 9 1Kly 1.5HutBeam Phase Cavity 2 0.5HutL0-A Accelerator 4 1Kly 0.5HutL0-B Accelerator 4 1Kly 0.5HutL0-T Transverse Accelerator 4 1Kly 0.5HutL1-S Station 21-1 B, C, and D Acc 6 1Kly 1.0HutL1-X X-Band accelerator X-Band 5 1Kly 0.5HutS25-Tcav 4 1KlyS24-1, 2, & 3 Feedback 0S29 and S30 Feedback 0

Total Chassis 7Kly 6HutTotal into Hut IOC 12



September 19, 2006

RF Control Signal CountsDistribution (3~2850MHz, 3<500MHz) 6 IQ ModRF Gun 1 Klystron Beam Phase Cavity 1 IQ modL0-A Accelerator 1 KlystronL0-B Accelerator 1 KlystronL0-T Transverse Accelerator 1 KlystronL1-S Station 21-1 B, C, and D accelerators 1 Klystron

L1-X X-Band accelerator X-Band 1 IQ ModS25-Tcav 1 KlystronS24-1, 2, & 3 Feedback 3 KlystronsS29 and S30 Feedback 2 IQ modulators 476MHz

Total modulators 11 Fast 8 Slow 19 modulatorsTotals at ~2856MHz 14 modulatorsTotal into Hut IOC 14 modulators



September 19, 2006

LLRF Control and Monitor System

LLRF Control and Monitor System1 kW Solid State S-Band Amplifiers – 5 units

Phase and Amplitude Monitors – 12 units

Phase and Amplitude Controllers – 6 units

Bunch Length Monitor Interface – Need Specifications



September 19, 2006

RF Control

RF Control Module consist of the following:

Input Coupler, IQ Modulator, Amplifier, Output Coupler

Filters for I and Q inputs

I

RFLO

Q

1

2

34

BXMP1007

2856MHz Input Monitor 2856MHz Output Monitor

Q Control

RF InRF Out

I Control

17dBm 0dBm

2850MHz IQ Modulator

17dBm

Required 13 UnitsIncludes Distribution



September 19, 2006

RF MonitorRequired 13 Chassis for Injector – Includes DistributionLO 2830.5MHz : RF 2856MHzIF 25.5MHz (8.5MHz x 3 in sync with timing fiducial)Double-Balanced MixerMixer IF to Amp and then Low Pass FilterFilter output to ADC sampling at 102MSPS

MIXER

LOR

F IF

Amplifier

25.5MHz BP FILTER

2830.5MHz Local Osc.

2856MHz RF Signal

To ADC

LTC2208 SNR = 77dBFS

102MSPS



September 19, 2006

1 kW Solid State S-Band Amplifiers

Design Complete Two Units on the ShelfModules in house – and testedSupport parts – Some parts in house

Power Supplies, relays, chassis on order



September 19, 2006

SLAC Linac RF – New ControlThe new control system will tie in to the IPA Chassis with 1kW of drive power available. Reference will be from the existing phase reference line or the injector new RF reference

I and Q will be controlled with a 16bit DAC running at 119MHz. Waveforms to the DAC will be set in an FPGA through a microcontroller running EPICS on RTEMS.

Existing System Accelerator

Klystron

Next Sector

MDL 476MHz

SubBooster

6 X2856MHz

Sub Drive Line

High PowerPhase ShifterAttenuator

SLED

Phase &AmplitudeDetector

ExistingPhaseReferenceLine

-45dB200MW

3kW

20mW

1W1mW

To NextKlystron

I

RF LO

Q

1

2

3

4

IQ Modulator

1kW Amp2856MHz

IPA



September 19, 2006

Controls Talk



September 19, 2006

LLRF Controls

OutlineRequirementsExternal InterfacesSchedule

Date NeededPrototype Completion DateHardware Order DateInstallationTest Period

Design Design Maturity (what reviews have been had) State of Wiring Information State of Prototype



September 19, 2006

Requirements

At 120 Hz, meet phase/amp noise levels defined as:

0.1% rms amplitude 100 fs rms in S-band (fill time = 850 ns) 125 fs rms in X-band (fill time = 100 ns)All tolerances are rms levels and the voltage and phase tolerances per klystron for L2 and L3 are Nk larger, assuming uncorrelated errors, where Nk is the number of klystrons per linac (L2 has 28; L3 has 48)



September 19, 2006

Engineering Requirements

When beam is present, control will be done by beam-based longitudinal feedback (except for T-cavs); when beam is absent, control will be done by local phase and amplitude controller (PAC)

Adhere to LCLS Controls Group standards: RTEMS, EPICS, Channel Access protocol

Ref: Why RTEMS? Study of open source real-time OS

Begin RF processing of high-powered structures May 20, 2006



September 19, 2006

External Interfaces

LLRF to LCLS global control system PVs available for edm screens, archiving, etc over controls network

LLRF VME to beam-based longitudinal feedback from feedback: phase and amplitude corrections at 120 Hz over private ethernet from LLRF: phase and amplitude values

(internal) LLRF VME to LLRF microcontrollers from VME: triggers, corrected phase and amplitude from microcontrollers: phase and amplitude averaged values at 120 Hz, raw phase and amplitude values for debug



September 19, 2006

External Interfaces: Laser - Tcav

I and Q Demo-dulator

CPU

FIFOs

DAC

slow

Temperature monitors

EVR

Laser and RF ref

L0-AL0-B

L1-SL1-X

T Cav

gun

Controls gigabit ethernet (interface to MCC)

Private ethernet8 kBytes at 120 Hz

PAD

ADC

FPGADAC

1 trigger for 4

channels of 1k

samples


In-house modules sharing VME crate for timing triggers

476 MH

z RF R

eferen

ce clo

ck dis

tribute

d to all

30 se

ctors i

n the L

inac a

nd bey

ond

RF Reference/4 = 119 MHzstabilized to 50 fs jitter

RF Reference*6 = 2856 MHzstabilized to 50 fs jitter

Coldfire CPU

running RTEMS

and EPICS

Coldfire CPU

running RTEMS

and EPICS

PAC

RF Phase and Amplitude correction at 120 Hz for:laser, gun, L0-A, L0-B, L1-S, L1-X, T cav

10' accelerator

IQ Modulator gives phase

and amplitude control

1 kW 1 kW

Solid State Sub Booster

Klystron

SLED cavity

60 MW

HPRF240 MW

60 MW

1 kW

All except laser RF

100 mW

119 MHz Laser

Oscillator

Amps

GunNB: For the gun, SLED

cavity is shorted out

119 MHz120 Hz

UV

photodiode

photodiode

1 trigger to travel up to ½ sector

away

DAC

slow

VME Crate at S20 running

longitudinal, beam-based

feedback

Private ethernet



September 19, 2006

External Interfaces: L2-L3

I and Q Demo-dulator

CPU

FIFOs

DAC

slow

Temperature monitors

EVR

Laser and RF ref

L0-AL0-B

L1-SL1-X

T Cav

gun

Controls gigabit ethernet (interface to MCC)


PAD

ADC

FPGADAC

1 trigger for 4

channels of 1k

samples


In-house modules sharing VME crate for timing triggers

476 MH

z RF R

eferen

ce clo

ck dis

tribute

d to all

30 se

ctors i

n the L

inac a

nd bey

ond

RF Reference/4 = 119 MHzstabilized to 50 fs jitter

RF Reference*6 = 2856 MHzstabilized to 50 fs jitter

Coldfire CPU

running RTEMS

and EPICS

Coldfire CPU

running RTEMS

and EPICS

PAC

RF Phase and Amplitude correction at 120 Hz for:laser, gun, L0-A, L0-B, L1-S, L1-X, T cav

10' accelerator

IQ Modulator gives phase

and amplitude control

1 kW 1 kW

Solid State Sub Booster

Klystron

SLED cavity

60 MW

HPRF240 MW

60 MW

1 kW

All except laser RF

100 mW

119 MHz Laser

Oscillator

Amps

GunNB: For the gun, SLED

cavity is shorted out

119 MHz120 Hz

UV

photodiode

photodiode

1 trigger to travel up to ½ sector

away

DAC

slow



feedback

Private ethernet



September 19, 2006

DesignDesign maturity (what reviews have been had):

RF/Timing Design, DOE Review, August 11, 2004 Akre_FAC_Oct04_RF_Timing, FAC Review, October, 2004 Low Level RF Controls Design, LCLS Week, January 25-27, 2005 Low Level RF, Lehman Review, May 10-12, 2005 LLRF Plans for Development and Testing of Controls, LCLS Week, July 21, 2005 Low Level RF Design, Presentation for Controls Group, Sept. 13, 2005 LLRF Preliminary Design review, SLAC, September 26, 2005 LCLS LLRF Control System - Kotturi, LLRF Workshop, CERN, October 10-13, 2005 LCLS LLRF System - Hong, LLRF Workshop, CERN, October 10-13, 2005 LLRF and Beam-based Longitudinal Feedback Readiness - Kotturi/Akre, LCLS Week, SLAC, October 24-26, 2005 LCLS Week LLRF and feedback - Kotturi/Allison, LCLS Week, SLAC, October 24-26, 2005 LLRF, LCLS System Concept Review/Preliminary Design Review, SLAC, November 16-17, 2005 Comments LLRF Beam Phase Cavity Preliminary Design review, SLAC, November 30, 2005

Docs at: http://www.slac.stanford.edu/grp/lcls/controls/global/subsystems/llrfState of wiring: percent complete Captar input will be given at time of presentation State of prototype: PAD (1 chan ADC) and PAC boards built (shown on next pages).Testing.



September 19, 2006

PAD – the monitor board



September 19, 2006

PAD – the monitor board

2 X 16 bit ADC119 or 102MHz ClockLTC2208Transformer Coupled Inputs

Chan. 2

Chan. 1

FIFO 2 X 1k words

WCLK

16bit DATA

16bit DATA

WCLK

RF CHAN 1INPUT

RF CHAN 2INPUT

Line DriversFilters

MIXER

LORF

IF

MIXER

LORF

IF

RF Board

25.5MHz IF

Control Board

Control

EXTERNALTRIGGER120Hz

EXTERNALCLOCK102MHz

CS/CLK

16 bitDATA

CONTROL /Arcturus uC5282Microcontroller Modulewith 10/100 Ethernet

ET

HE

RN

ET

LO INPUTRF - 25.5MHz

CPLD



September 19, 2006

PAC – the control board



September 19, 2006

PAC – the control board

SSSBChassis

Temperature MonitorForward Power 0-?VReflected Power 0-?VOver Temp 0 or 12V Power Supplie +12VPower Supply -12V

I

R F L O

Q

I&Q MODULATOR

1

2

3

4

MAX58752 X 16 bit DAC119MHz Clock(1MHz to 200MHz)

I

Q

XILINXSPARTAN 3FPGA

16bit DATA

CS/CLK

16bit DATA

16 bitDATA

CLK

CLK CONTROL /Arcturus uC5282Microcontroller Modulewith 10/100 Ethernet

ET

HE

RN

ET

Control Control

RF OUTPUTTo SSSB

TRIGGERMonitor TTL

EXTERNALTRIGGER120Hz60nS NIM

2856MHz Ref

MONITORPORTS

AD8099 Diff Amp

SSSBTrigTTL17 to 30uS

Thermocouples

CLOCK119MHz

RF BOARD

t


TemperatureMonitor t

DC PowerSupplies

DC PowerSupplyMonitors

Control BoardADCs

TemperatureMonitor



September 19, 2006

Additional Slides

The following two pages show an overview of the LLRF control modules. From these diagrams, counts of module types, as well as function and location are seen.



September 19, 2006

Eth recvr

EVR



feedback.

CPU

PAC

Gun

PADPADPAD

SPAC

RF Dist’n

Laser

PAC

L0-B

PADPAD

PAC

L1-S

PADPAD

PACL0-Tcav

PADPAD

PACL0-A

PADPAD

SPAC

PAD

PAD PAC

Beam Phase Monitor

PAD

SPACSPACSPAC

SPACPAD

Fast PACs: Slow PACs (SPACs): PADs: VME crates:

RF phase and amplitude correction and global feedback at 120 Hz for LCLS LINAC S20

PAC

L1-X

PADPADPAD

PAD

PAC

Key:

Indicates may be needed

86191

S20

The maybe is included in counts below

Indicates located in RF HutOtherwise at Klystron

Overview of LLRF at Sector 20



September 19, 2006

Overview of LLRF at Sector 24

Fast PACs: Slow PACs (SPACs): PADs: VME crates:

Eth recvr

EVR

CPU

PAC

L24-1

PACL24-2

PACL24-3

PACTcav L24-8

SPAC

S29

SPAC

S30

PADPAD



feedback.

4221

S24

RF phase and amplitude correction and global feedback at 120 Hz for LCLS LINAC S20



September 19, 2006

Beam Phase MonitorR. Akre

A. Haase

B. Hong

D. Kotturi

V. Pacak

H. Schwarz

Preliminary Design Review

November 30, 2005



September 19, 2006

Outline

•Purpose

•Specifications

•System outline

•Cavity

•Noise Levels

•Analysis

•Long Term Drifts

•Summary



September 19, 2006

Laser Timing Stabilization Feedback

Beam timing information from the beam phase monitor will be used to apply corrections to the timing of the laser on the RF Gun.

PHAS AMPL

TOROID

BUNCH CHARGE

BEAM PHASE CAVITY

GUN RF FEEDBACK

InputsGUN-CELL1-PHAS/AMPLGUN-CELL2-PHAS/AMPL

ActuatorsGUN RF ACTUATORS

2856MHz R ef

GUN RF ACTUATORS

LCLS RF Oscilla tor

LINAC MDL Ref.

GUN RF REF.

LASER RF R EF.

PHAS

PHASEERROR

ActuatorL0, L1 to L2, L3Phase

LASER POWERACTUATOR

OUT

GUN-CELL2

GUN-CELL1

KLYSTRONAMPLIFIER / SLC CONTROL

LASER OSC

Reference

LASER PHASE & AMPLITUDE?

LASER AMPLIFIER

LASER OSC. PHASE

WATER TEMP

RF GUN

LASER PHASE ACTUATOR

LASER OSCILLATOR PHASEFEEDBACK

InputsBEAM PHASE CAVITY

ActuatorsLASER PHASE ACTUATOR

PHASE ERROR BetweenL0, L1 and L 2, L3

AMPL

LASER OSCILLATOR PHASEand LASER POWERFEEDBACK

InputsLASER OSC. PHASEBUNCH CHARGEGUN-CELL1-AMPL/PHASGUN-CELL2-AMPL/PHASLASER PHASE & AMPLITUDEGUN RF ACTUATORSBEAM PHASE CAVITY

ActuatorsLASER POWERLASER PHASE ACTUATOR

GUN TUNE FEEDBACK

InputsGUN-FOR-PHASGUN-CELL1-PHASGUN-CELL2-PHAS

ActuatorsWATER TEMP

GUN-FOR

2856MHzRF REF.

LASER

GUN

L0A

L0B

L0-TCAV1

L1-X

L1-S



September 19, 2006

Specifications

Short term (2 second) timing jitter: 100fS rms

Long term (4 day) timing jitter: ±1pS

Range of the above accuracies is ±10pS

Data available at 120Hz



September 19, 2006

System Outline



September 19, 2006

Cavity

Frequency = 2856MHz

Q = 6000

Time Constant = 700nS

Temperature Coefficient = 50kH/°C



September 19, 2006

System Critical Noise Levels and Bandwidths

Cavity Signal – Bandwidth 500kHz

Local Oscillator – Noise Floor –143dBc/Hz

IF Filter – Bandwidth 4MHz

ADC – SNR at input 76dB



September 19, 2006

System Critical Noise Levels and Bandwidths

2830.5MHz Oscillator

1

Beam Phase Cavity

Attenuator

Monitor Port

Coupler

MIXER

LO

RF

IF

Monitor Port

In TunnelAmp

Filter - Butterworth3rd order BandPass2.5.5MHz Center4.0MHz BW2dB IL at 25.5MHz

30dBm pk

ADC LTC22082.25Vpp FSTransformer coupled102MHz Clock

30dBm pk

Attenuator

3dBm pk23dBm pk

2Vpp 10dBm pk

13dBm

-3dBm pk 17dBm pk

-130dBm/Hz-143dBc/Hz

-174dBm/Hz-174dBm/Hz

-129dBm/Hz-143dBc/Hz

-146dBm/Hz-143dBc/Hz Within filters BW

-135dBm/Hz-143dBc/HzBeyond 5MHz from CF<-155dBm/Hz<-163dBc/HzIntegrated Noise-77dBc

Generated from 119MHz OscillatorExpected SSB Phase Noise LevelsOffset Hz dBc/Hz @ 2830.5MHz10 -82100 -961k -12410k -14420k -146

ADC SNR 77dBFS



September 19, 2006

ADC Linear Technologies LTC2208

16Bit 130MHz

SNR 77.6dBFS 30MHz in Clock 130MHz SFDR 95dB



September 19, 2006

AnalysisPhas

e

Calculated Beam Phase at Beam Time

Measured Data Point 1

Measured Data Point 2

Time



September 19, 2006

I & Q from WaveformDigital Down Mixing and Normalization

0 10 20 30 40 50 600.6

0.4

0.2

0

0.2

0.4

0.6

0.8

125.5MHz Digitized Signal

Point Number

Fra

ctio

n A

DC

Ful

l Sca

le

.

Digitized

Input Signal



September 19, 2006

Optimization

Optimal Points to use for analysis is 16 point average at points 18 and 120



September 19, 2006

Analysis Results

Standard deviation of result = 1.1e-4 or 6.3fS rms jitter

Signal level 20dB lower will give 63fS rms jitter

Sensitivity to frequency change = 0.6fS/2.8kH freq change

Sensitivity to timing change over +-10deg = 1:1



September 19, 2006

80ft (1M deg) of ½ inch superflex has TC of 4ppm/degCWater temp tolerance is +-0.1degF = +-400fS drift

Long Term Drifts



September 19, 2006

Summary

Short term (2 second) timing jitter: 100fS rms

63fS rms

Long term (4 day) timing jitter: ±1pS

±0.8pS

Range of the above accuracies is ±10pS

Results

Data available at 120Hz

Simple algorithm in integer arithmetic will allow this



September 19, 2006

Feedback Page 1

LOCAL FEEDBACK

LOCAL FEEDBACK



September 19, 2006

Feedback Page 2

LOCAL FEEDBACK

GLOBAL FEEDBACK



September 19, 2006

Feedback Page 3LOCAL FEEDBACK

LOCAL FEEDBACK

GLOBAL FEEDBACK



September 19, 2006

Feedback Page 4GLOBAL FEEDBACK



September 19, 2006

Feedback Page 5GLOBAL FEEDBACK



September 19, 2006

Feedback Page 6

Documents

Ron Akre, Dayle Kotturi LCLS LLRF [email protected]@slac.stanford.edu, [email protected]@slac.stanford.edu September 19, 2006