Diagnostics (WBS 1.5) Yiping Feng

Yiping [email protected]

LUSI DOE Review July 23, 2007Diagnostics (WBS 1.5) 1

Diagnostics(WBS 1.5)Yiping Feng

Diagnostics(WBS 1.5)Yiping Feng

System SpecificationsSystem DescriptionTechnical ChallengesWBSSchedule and CostsSummary

System SpecificationsSystem DescriptionTechnical ChallengesWBSSchedule and CostsSummary



Expected Fluctuations of LCLS FEL pulsesExpected Fluctuations of LCLS FEL pulses

Parameter Value Origin*

Pulse intensity fluctuation

~ 30 %Varying # of FEL producing SASE spikes; 100% intensity fluctuation/per-spike; etc.

Position & pointing jitter (x, y, , )

~ 25 % of beam diameter

~ 25 % of beam divergence

Varying trajectory per pulse; Saturation at different locations of -tron curvature

Source point jitter (z) ~ 5 m SASE process reaching saturation at different z-points in undulator

X-ray pulse timing (arrival time) jitter

~ 1 ps FWHMTiming jitter btw injection laser and RF; Varying e-energy per-pulse

X-ray pulse width variation

~ 15 %Varying e-energy leading to varying path (compression) in bunch compressors

Center wavelength variation

~ 0.2 % (comparable to FEL bandwidth)

Varying e-energy leading to varying FEL fundamental wavelength and higher order

*Discussed in Breakout Summary Session



X-ray Diagnostics SuiteX-ray Diagnostics Suite

Fluctuation Type Diagnostic Device

Pulse intensity fluctuationa) Pop-In Intensity Monitorb) In-Situ BPM/Intensity Monitor

Position & pointing jitterc) Pop-In Position/Profile MonitorIn-Situ BPM/Intensity Monitor- Pointing determination from multiple BMP’s

Source point jitter Focal point jitter w/ focusing optics

d) Wave-front Sensor- Back-propagating from radius of curvature measurement

X-ray pulse timing jittere) Electro-Optic Sampling (EOS) Device- Relative timing btw e-bunch & ref. probe laser

X-ray pulse width variation EOS Device- Establishes upper limit

Center wavelength variation LCLS e-energy calibration- X-ray wavelength cross-calibration is needed



System SpecificationsSystem Specifications

Diagnostic Item Purposes Specifications*

Pop-inintensity monitor(moderate-resolution)

Coarse beam alignment/monitoring;

Destructive; Retractable;Dynamic range 104;Per-pulse operation at 120 Hz;Relative accuracy < 10-2

Pop-inposition/profile monitor

Coarse beam alignment/monitoring

Destructive; Retractable;At 50 m resolution - 25x25 mm2 field of view;At 10 m resolution - 5x5 mm2 field of view

In-situIntensity Monitor/BPM(high-resolution)

Per-pulse normalization of experimental signals;High-resolution beam position monitoring

Transmissive (< 5% loss); Dynamic range 106;Per-pulse operation at 120 Hz;Relative accuracy < 10-3

In-situ Electro-optic sampling (EOS) device

Measure relative timing between electron bunch (thus co-propagating x-ray pulse) and a probe optical laser pulse

Non-intrusive to e-beam;Non-destructive; Per-pulse operation at 120 Hz;20 fs resolution;

In-situWave-front sensor

Characterization of wave-front;Locating focal point of focused beam

Destructive; Per-pulse operation at 120 Hz;0.15 nm < < 0.3 nm

* Must have high damage threshold

Tech

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Quantities of DiagnosticsQuantities of Diagnostics

Pop-inIntensityMonitor

Pop-inPositionMonitor

In-situIntensityMonitor

EOSDevice

Wave-frontSensor

XPP 3 4 2 1

CXI 6 6 2 1

XCS 16 16 2

Diagnostics

Station

Standardized and ModularizedStandardized and Modularized



CXI

Placement of DiagnosticsPlacement of Diagnostics

XCS

XPP

XPP(EO in LTU)

CXI

XCS



Detailed Placement in XPPDetailed Placement in XPP



Pop-In Intensity Monitor (WBS 1.5.3)Pop-In Intensity Monitor (WBS 1.5.3)

Coarse alignment of X-ray opticsmonochromators, mirrors, lens, etc.strategically placed in close proximity to optic

Detection techniquePulse operation not photon countingSensor type

Si Diode (used successfully at SPPS)CVD Diamond

Coarse alignment of X-ray opticsmonochromators, mirrors, lens, etc.strategically placed in close proximity to optic

Detection techniquePulse operation not photon countingSensor type

Si Diode (used successfully at SPPS)CVD Diamond

Destructive; Retractable;Moderate dynamic range 104; Relative accuracy < 10-2;Per-pulse operation at 120 Hz;

Si Diode

stages

FEL



Pop-In Position/Profile Monitor (WBS 1.5.2)Pop-In Position/Profile Monitor (WBS 1.5.2)

Destructive; Retractable;At 50 m resolution 25x25 mm2 field of view;At 10 m resolution 5x5 mm2 field of view;

Coarse alignment of X-ray optics (beam finder)

Optical imaging of fluorescence from a scintillating screen

Positions in x, y2D intensity profile

Attenuation of beam may be required to avoid saturation

Two modes of operation: low and high resolutions

Coarse alignment of X-ray optics (beam finder)

Optical imaging of fluorescence from a scintillating screen

Positions in x, y2D intensity profile

Attenuation of beam may be required to avoid saturation

Two modes of operation: low and high resolutions

CCD Camera

YAG Screen

Mirror

FEL

stages



a a

a

N=12463

Diagnostic needs: Ultrafast Measurement of Atomic Displacement – an example

Diagnostic needs: Ultrafast Measurement of Atomic Displacement – an example

Precise normalization of incident intensity to 0.1%Critical to XPP experiments: small changes in diffraction intensity need to be resolved

Relative timing btw e-bunch & EOS-probe laser pulse - Inferring timing btw X-ray pulse & experimental probe laser

Precise normalization of incident intensity to 0.1%Critical to XPP experiments: small changes in diffraction intensity need to be resolved

Relative timing btw e-bunch & EOS-probe laser pulse - Inferring timing btw X-ray pulse & experimental probe laser

D. M. Fritz et al., Science 315, 633 (2007)



In-Situ Intensity/Position Monitor (WBS 1.5.4)In-Situ Intensity/Position Monitor (WBS 1.5.4)

Transmissive (> 98% w/ 100 m Be @ 8 keV);High dynamic range 106;Relative accuracy < 10-3

Position resolution < 5 m;Per-pulse operation at 120 Hz;

Precise normalization of incident intensity to 0.1%

Critical to XPP experiments where small change in diffraction intensity need to be resolved, i.e. Bi coherent phonon decay after photo-excitation

Detection techniqueCompton back scattering from Be thin foil (up to 108 photons w/ 1012 in incident beam)

Precise beam position calibration w/ use of array of sensors to < 5 m

Commercial fluorescence monitor using similar design provides equal resolution but not viable due to damage considerationsCVD diamond design more complex in fabrication

Precise normalization of incident intensity to 0.1%

Critical to XPP experiments where small change in diffraction intensity need to be resolved, i.e. Bi coherent phonon decay after photo-excitation

Detection techniqueCompton back scattering from Be thin foil (up to 108 photons w/ 1012 in incident beam)

Precise beam position calibration w/ use of array of sensors to < 5 m

Commercial fluorescence monitor using similar design provides equal resolution but not viable due to damage considerationsCVD diamond design more complex in fabrication

Be thin foil

FEL

Quad-sensor



In-Situ Intensity/Position MonitorIn-Situ Intensity/Position Monitor

Si Diode Used at SPPS

2 mm

400 m thick

Pulse Detection Circuitry

Single photon10^4 range



AcceleratingElements

ExperimentalPump Laser

Master Clock RF

Distribution Network

Laser/FEL TimingLaser/FEL Timing

Sources of short-term jitterE-beam phase to RF phase jitter

Electron beam energy jitter + dispersive electron optics

End station laser phase to RF Phase locking jitter

Short-term timing resolution ~ 1 ps

Long-term jitterLength of RF cable thermal variation

Sources of short-term jitterE-beam phase to RF phase jitter

Electron beam energy jitter + dispersive electron optics

End station laser phase to RF Phase locking jitter

Short-term timing resolution ~ 1 ps

Long-term jitterLength of RF cable thermal variation

ElectronGun

Timing jitter reduces the visibilityof experimental effects



Electro-Optic Sampling Device (WBS 1.5.6)Electro-Optic Sampling Device (WBS 1.5.6)

Non-intrusive to e-beam;Non-destructive; Per-pulse operation at 120 Hz;

Relative timing btw e-bunch & EOS-probe laser pulse Inferring timing btw X-ray pulse &

experimental probe laser

Based on (linear) Pockels effectbirefringence in strong E-field exerted by relativistic e-bunch in proximity1-D Spatial encoding of timing for detection using CCD

Single shot measurement

EOS technique proven at SPPS20 fs timing determination200 fs resolution for e-bunch length

ChallengesLong distance btw EOS location (LTU) & experiments (NEH)120 Hz operation requires real-time processing of EOS data

Relative timing btw e-bunch & EOS-probe laser pulse Inferring timing btw X-ray pulse &

experimental probe laser

Based on (linear) Pockels effectbirefringence in strong E-field exerted by relativistic e-bunch in proximity1-D Spatial encoding of timing for detection using CCD

Single shot measurement

EOS technique proven at SPPS20 fs timing determination200 fs resolution for e-bunch length

ChallengesLong distance btw EOS location (LTU) & experiments (NEH)120 Hz operation requires real-time processing of EOS data

EOScrystal

Probe-laser footprint



Enhanced Laser/FEL Timing @ LCLSEnhanced Laser/FEL Timing @ LCLS

Electro-optic SamplingEnhanced Temporal Resolution (~ 100 fs)

Limited by our ability to phase lock the lasers to the RF backboneLimited by Intra-bunch SASE jitter

Electro-optic SamplingEnhanced Temporal Resolution (~ 100 fs)

Limited by our ability to phase lock the lasers to the RF backboneLimited by Intra-bunch SASE jitter

Electro-optic Sampling Laser

Pump-probeLaser

LTU NEH

Gun Laser

Sector 20

Stabilized Fiber Optic LLRF Distribution Network (< 10 fs)Developed by LBNL

Hub

fiber link



Length-Stabilized Fiber NetworkLength-Stabilized Fiber Network



Hartmann Wave-front Sensor (WBS 1.5.5)Hartmann Wave-front Sensor (WBS 1.5.5)

Characterization of wave-front of focused X-ray FEL is a challenge

Critical to CXI experiments if atomic resolution is ultimately to be achievedCommon scanning or direct imaging techniques made at focus not viable due to FEL high peak power

Hartmann Wave-front Sensor technique is viableMeasurement made far from focusFocal point determination calculated from radius of curvature measurementWave-front distortion obtained by back-propagation of diffracted wave-front determined at mask plane

Commercial Hartmann wave-front for long wavelengthSuccessful in optical applications (adaptive optics, etc.)For X-ray applications, X-EUV sensor for energy up to 4 keVNeeds modification for higher energies and 120 Hz operation

Characterization of wave-front of focused X-ray FEL is a challenge

Critical to CXI experiments if atomic resolution is ultimately to be achievedCommon scanning or direct imaging techniques made at focus not viable due to FEL high peak power

Hartmann Wave-front Sensor technique is viableMeasurement made far from focusFocal point determination calculated from radius of curvature measurementWave-front distortion obtained by back-propagation of diffracted wave-front determined at mask plane

Commercial Hartmann wave-front for long wavelengthSuccessful in optical applications (adaptive optics, etc.)For X-ray applications, X-EUV sensor for energy up to 4 keVNeeds modification for higher energies and 120 Hz operation



Hartmann Wave-front Sensor (con’t)Hartmann Wave-front Sensor (con’t)

Image obtained from

Imagine Optics, Ltd

ChallengesWorking at 8 keV

Tighter technical specs at shorter wavelengthMask must allow ray-optics approximationNew 8 keV version being developed & tested nowMask materials must be compatible with FEL application

120 Hz operation will require customizationImaging sensor readout rate not sufficient

Use pixelated detector capable of 120 Hz operationIntegrate with Controls/Data systems

ChallengesWorking at 8 keV

Tighter technical specs at shorter wavelengthMask must allow ray-optics approximationNew 8 keV version being developed & tested nowMask materials must be compatible with FEL application

120 Hz operation will require customizationImaging sensor readout rate not sufficient

Use pixelated detector capable of 120 Hz operationIntegrate with Controls/Data systems

Algorithm

Divergent

wavefront



Hartmann Wavefront SensorHartmann Wavefront Sensor

Focal PlaneFocusing Optic

2D Detector

FEL Beam

Hartmann Plate

Variable Description Value Value Value

f Focal length 0.4 m 4 m 40 m

D Focus to Hartmann plate distance 5 m 15 m 15 m

L Hartmann plate to detector distance 100 mm 100 mm 100 mm

N Number of hole in Hartmann plate 75x75 75x75 75x75

D Hole spacing 130 mm 130 mm 130 mm

w0 Focal spot size 0.1 mm 1 mm 10 mm

W Beam size at Hartmann plate 5 mm 1.5 mm 0.15 mm*

f D L

Ww0

*Requires a defocusing optic



Diffractive Wavefront ReconstructionDiffractive Wavefront Reconstruction

The oversampled diffraction pattern of the focus is measured.The focal spot is iteratively reconstructed by propagating the wave from the optic to the focus and then to the detector plane.

The constraints are applied at the optic and detector planes.

The oversampled diffraction pattern of the focus is measured.The focal spot is iteratively reconstructed by propagating the wave from the optic to the focus and then to the detector plane.

The constraints are applied at the optic and detector planes.

FocalPlane

Focusing Optic

2D Detector

FEL Beam

f L

Ww0

Attenuator



Diffractive ImagingDiffractive Imaging

Nature PhysicsVol 2. p101



1.5 WBS1.5 WBS

1.5Diagnostics

1.5.1Physics SupportEng. Integration

1.5.2Pop-in Position

Monitor

1.5.3Pop-in Intensity

Monitor

1.5.4In-situ Intensity

Monitor

1.5.5In-situ Wave-front

Sensor

1.5.2.1Engineering &

1st article const.

1.5.2.2XPP

1.5.2.3CXI

1.5.2.4XCS


1st article const.

1.5.3.2XPP

1.5.3.3CXI

1.5.3.4XCS


1st article const.

1.5. 4.2XPP

1.5.4.3CXI

1.5.4.4XCS

1.5.5.1Engineering

1.5.5.2CXI

1.5.6In-situ EOS

Device

1.5.6.1Engineering

1.5.6.2XPP



Diagnostics Schedule in Primavera 3.1Diagnostics Schedule in Primavera 3.1



Diagnostics MilestonesDiagnostics Milestones

CD-1 Aug 01, 07Conceptual Design Complete Oct 24, 07CD-2a Dec 03, 07CD-3a Jul 21, 08EOS monitor complete Oct 20, 08Pop-in position/profiler 1st article Nov 25, 08In-situ intensity/position 1st article Jan 21, 09Pop-in intensity 1st article Apr 15, 09Phase I Installation Complete Aug 21, 09CD-4a Feb 08, 10

CD-1 Aug 01, 07Conceptual Design Complete Oct 24, 07CD-2a Dec 03, 07CD-3a Jul 21, 08EOS monitor complete Oct 20, 08Pop-in position/profiler 1st article Nov 25, 08In-situ intensity/position 1st article Jan 21, 09Pop-in intensity 1st article Apr 15, 09Phase I Installation Complete Aug 21, 09CD-4a Feb 08, 10



Diagnostics Cost Estimate Diagnostics Cost Estimate

Direct Cost $2,326.2PED $700.0MS&T $1,376.2ASSY $250.0

Indirect Cost $630.0Escalation $210.0Total Cost $3,166.2

Associated Contingency 35.1%

IndirectCosts

Escalation

PED

MS&T

ASSY

DirectCosts



1.5 Level 3 Costs (M$)1.5 Level 3 Costs (M$)



WBS 1.5 - DiagnosticsWBS 1.5 - Diagnostics

Cost estimate at level 3 by fiscal year – Cost estimate at level 3 by fiscal year –



SummarySummary

Concepts of all diagnostic devices are well developed

Frequent design discussions amongst LUSI and LCLS scientistsEOS device was successfully deployed at SPPS

1st articles will help LCLS commissioning/operation and early science on LUSI instruments

LUSI EOS will aid LCLS e-beam diagnosticsLUSI BPM could aid LCLS e-beam fast feedback system

Ready to proceed with baseline cost and schedule development

Concepts of all diagnostic devices are well developed

Frequent design discussions amongst LUSI and LCLS scientistsEOS device was successfully deployed at SPPS

1st articles will help LCLS commissioning/operation and early science on LUSI instruments

LUSI EOS will aid LCLS e-beam diagnosticsLUSI BPM could aid LCLS e-beam fast feedback system

Ready to proceed with baseline cost and schedule development

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Diagnostics (WBS 1.5) Yiping Feng

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