XTOD Diagnostics for Commissioning the LCLS* January 19-20, 2003 LCLS Undulator Diagnostics and Commissioning Workshop Richard M. Bionta *This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48 and by Stanford University, Stanford Linear Accelerator Center under contract No. DE-AC03-76SF00515.
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XTOD Diagnostics for Commissioning the LCLS* January 19-20, 2003 LCLS Undulator Diagnostics and Commissioning Workshop Richard M. Bionta January 19-20,
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XTOD Diagnostics for Commissioning the LCLS*
XTOD Diagnostics for Commissioning the LCLS*
January 19-20, 2003LCLS Undulator Diagnostics and Commissioning
WorkshopRichard M. Bionta
January 19-20, 2003LCLS Undulator Diagnostics and Commissioning
WorkshopRichard M. Bionta
*This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-
Eng-48 and by Stanford University, Stanford Linear Accelerator Center under contract No. DE-AC03-76SF00515.
*This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-
Eng-48 and by Stanford University, Stanford Linear Accelerator Center under contract No. DE-AC03-76SF00515.
Ginger provides complex Ginger provides complex Electric Field envelope at Electric Field envelope at undulator exitundulator exit
23768 8N
Data in the form of
radial distributionsof complex numbersrepresenting theenvelope of the Electric Field at theundulator exit. tit
c
nt
16n
Samples are separated in time by
wavelengths.
Time between samples is
Ni ..1R, mm0 150
Each radial distribution has
47NRradial points.
Electric Field Envelope Power Density vs timeat R = 0
wa
tts
/cm
2
R. M. Bionta
ToolsTools for manipulating GINGER for manipulating GINGER outputoutput
0 150
GINGER output:
Tables of electric field valuesat undulator exitat different times
Time Domain
Frequency Domain
TemporalTransform
SpatialTransform
00
1.94
150-150Transverse position, microns
x 1015 wattsc m2
Power Density
0
1.94
x 1015 wattsc m2
0 6Time, femtoseconds
42
Power Density
0w0w0-400/fs
1.73
x 1017 wattsc m2
w0+400/fs
frequency
Power Density
0-10
1.73
-325 304Wavenumber, mm-1
x 1017 wattsc m2
Power Density
viewer
Viewer
Transformation to Frequency Domain
Propagationto arbitrary
z
tit Ni ..1
R, mm
R. M. Bionta
FEL spatial FWHM downstream FEL spatial FWHM downstream of undulator exit, of undulator exit, l l = 0.15 nm= 0.15 nm
Transverse beam profile atundulator exit
Transverse beam profile15 m downstream of
undulator exit
FWHM vs. z at l = 0.15 nm
0
100
200
300
400
500
0 100 200 300
distance from undulator exit, meters
FW
HM
, mic
ron
s
Ginger(points)
Gaussian Beam(line)
R. M. Bionta
Total power at undulator exitTotal power at undulator exit
Total FEL Power
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
0.00 0.50 1.00 1.50 2.00
wavelength, nm
Gig
a-W
atts
Ginger simulations
Theoretical FEL saturation level
•10 Ginger simulations were run at different electron energies but with fixed electron emittance through 100 meter LCLS undulator.
•The Ginger runs at the longer wavelengths were not optimized, resulting in significant post-saturation effects. Results at longer wavelengths carry greater uncertanty.
R. M. Bionta
RMS BandwidthRMS Bandwidth
0
w0 = 12558 /fsw0 - 50 / fs
3
x 1
017
w
att
sc
m2
w0 + 50 /fs
frequency
Po
we
r D
en
sit
y
l= 0.15 nmTime Domain
l= 0.15 nmFrequency Domain
rms BW (%) vs wavelength (nm)
0.00
0.10
0.20
0.30
0.40
0.0 1.0 2.0
wavelength (nm)rm
s B
W (
%)
R. M. Bionta
FWHM vs wavelength at selected distances from undulator exit
0
250
500
750
1000
0.0 0.5 1.0 1.5
wavelength, nm
FW
HM
, mic
ron
s Ginger, 0 mGauss, 0 mGinger, 75 mGauss, 75 mGinger, 300 mGauss, 300 m
300 meters
75 meters
0 meters
FWHM vs. wavelength at 0, 75 FWHM vs. wavelength at 0, 75 and 300 metersand 300 meters
R. M. Bionta
We can confidently calculate the dose to transmissive We can confidently calculate the dose to transmissive optics.optics.
Low Z materials for transmissive optics can be chosen to survive in the LCLS experimental halls in the simple dose model on the left. The survivability of common high Z reflectors depends on additional assumptions.
Transmissive Dose Model
X-ray Photon
electron
atoms
Reflective Dose Model
R. M. Bionta
Dose / Power ConsiderationsDose / Power Considerations
0.01
0.1
1
10
100
100 1000 10000
Photon energy (eV)
Flu
en
ce (
J/cm
^2
)
undulatorexitexperimentalhall A
experimentalhall B
C
Si
W
Au
Be
0.01
0.1
1
10
0.1 1 10 100
grazing angle (degrees)
energ
y d
ensit
y c
orr
ect
ion
0.8 keV critical angle
0.8 keV
8 keV critical angle
8 keV
with electroncorrection
no electroncorrection
Fluence to Melt
Energy Density Reduction of a
Reflector
Be will melt at normal incidence at E < 3 KeV near undulator exit.
Using Be as a grazing incidence reflector may gain x 10 in tolerance.
R. M. Bionta
Roman’s far Field spontaneousRoman’s far Field spontaneous
R. M. Bionta
Detailed Spontaneous, in progressDetailed Spontaneous, in progress
R. M. Bionta
E > 400 KeVE > 400 KeV
R. M. Bionta
FEE InstrumentationFEE Instrumentation
R. M. Bionta
Front End Enclosure LayoutFront End Enclosure Layout
ValvePump
Pump
Slow valveFast valveFixed Mask
Slits
Diagnostics
WindowlessIon Chamber
Gas Attenuator
Solid Attenuator
Slits
Diagnostics
PPS
40mWestFace Near Hall
33mWestFace Dump
16.226 mEastface Last Dump MagWestface front End Enclosure
10.5 m
0 mEnd of Undulator
R. M. Bionta
Adjustable High-Power SlitsAdjustable High-Power SlitsAdjustable High-Power SlitsAdjustable High-Power SlitsIntended to intercept Intended to intercept
spontaneous beam, not FEL spontaneous beam, not FEL beam -- but will come very beam -- but will come very close, so peak power is an issueclose, so peak power is an issue
Two concepts being pursued Two concepts being pursued for slit jaws for slit jaws
Treat jaw as mirror (high-Z Treat jaw as mirror (high-Z material)material)
Treat jaw as absorber (low-Treat jaw as absorber (low-Z materialZ material
Either concept requires long Either concept requires long jaws with precision motionjaws with precision motion
Mechanical design based on Mechanical design based on SLAC collimator for high-energy SLAC collimator for high-energy electron beamelectron beam
R. M. Bionta
Front End Diagnostic TankFront End Diagnostic Tank
Direct Imager
Indirect Imager
ION Chamber
Turbo pump
Space for
calorimeter
BeIsolation
valve
Solid Filter Wheel Assembly
R. M. Bionta
Prototype LCLS X-Ray imaging cameraPrototype LCLS X-Ray imaging camera
CCDCamera
MicroscopeObjective
LSO or YAG:Ce crystal prism assembly
X-ray beam
X-ray beam
R. M. Bionta
Be Mirror Reflectivity
1.E-08
1.E-07
1.E-06
1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
Angle (degrees)
R
Indirect ImagerIndirect Imager
Be Mirror Reflectivity at 8 KeVBe Mirror Reflectivity at 8 KeV
1
0.1
0.01
0.001
0.0001
Be MirrorBe Mirror
Be Mirror angle provides "gain" adjustment Be Mirror angle provides "gain" adjustment over several orders of magnitudeover several orders of magnitude
R. M. Bionta
Multilayer allows higher angle and higher Multilayer allows higher angle and higher transmision but high z layer gets high dosetransmision but high z layer gets high dose
Be Mirror needs grazing incidence, camera close to beamBe Mirror needs grazing incidence, camera close to beam
Single high Z layer tamped by Be may hold togetherSingle high Z layer tamped by Be may hold together
R. M. Bionta
First check CCD by measuring First check CCD by measuring Response Equation CoefficientsResponse Equation Coefficients
crcrcrcrcr PtDCLQGd ,,,,, )(
crd ,
G
dQEL crcr )()( ,,
crDC ,
crQ ,
crP ,
t
Digitized gray level of pixel in row r, column c.
Electronic gain in units grays/photo electron.
Signal in units photo electrons.
Pixel Sensitivity non-uniformity correction.
Pixel Dark Current in units photo electrons/msec.
Pixel fixed-pattern in units grays.
Integration time in units msec.
R. M. Bionta
Photon Transfer CurvePhoton Transfer Curve
crcrcr PGtdGt ,Readout2
,,2 )()(
cr
crpixels
cr tdN
td,
,, )(1
)( Temporal mean gray level of pixel r,c.
cr
crcrpixels
cr tdtdN
t,
2,,,
2 )()(1
1)(
Temporal gray level fluctuations of pixel r,c.
R. M. Bionta
Calibration Data for one pixelCalibration Data for one pixel
Sigma Squared Vs. Mean
0
2000
4000
6000
8000
10000
12000
0 10000 20000 30000 40000 50000 60000 70000
Mean gray
Sigm
a Sq
uare
d
Mean gray vs. time
0
10000
20000
30000
40000
50000
60000
70000
0 1000 2000 3000 4000 5000 6000 7000
time, milliseconds
Me
an
Gra
y
crcrcr PGtdGt ,Readout2
,,2 )()(
crcrcrcrcr PtDCLQGd ,,,,, )(
R. M. Bionta
Calibration Coefficients for All PixelsCalibration Coefficients for All Pixels
R. M. Bionta
Photon Monte Carlo Simulations for predicting lens and Photon Monte Carlo Simulations for predicting lens and camera performancecamera performance
Camera Resolution in qualitative Camera Resolution in qualitative agreement with modelsagreement with models
1.5 mm
1.1 mm
1.5 mm
R. M. Bionta
Camera Resolution Quantitative Data Camera Resolution Quantitative Data Analysis in progressAnalysis in progress
R. M. Bionta
Micro Strip Ion ChamberMicro Strip Ion Chamber
Differentialpump
Differentialpump
Cathodes
Segmented horizontal
and vertical anodes
Isolation valve with
Be windowWindowless
FEL entry
R. M. Bionta
Gas AttenuatorGas AttenuatorGas AttenuatorGas Attenuator
For use when solid absorber risks damage (low-E FEL, front end)For use when solid absorber risks damage (low-E FEL, front end)Windowless, adjustable attenuationWindowless, adjustable attenuationCan provide up to 4 orders of magnitude attenuationCan provide up to 4 orders of magnitude attenuation
BB44C attenuators can tolerate C attenuators can tolerate FEL beam at E > 4 keV in FEL beam at E > 4 keV in FEE, and at all energies in FEE, and at all energies in experimental hutchesexperimental hutches
Spatial shape, centroid , and Spatial shape, centroid , and divergencedivergence
•FEE:•A1 •A2 •A4
FFTBHALL A
DiagnosticTanksFEE 1 & 3:
DiagnosticTankA1-1
CommissioningDiagnosticTankA4-1
Spatial shape, centroid , and divergence measured by combining data from the imagers in these tanks.
R. M. Bionta
Rad Sensor - a candidate technology for LCLS pulse Rad Sensor - a candidate technology for LCLS pulse length measurement and pump probe synchronizationlength measurement and pump probe synchronization
Rad sensor is an InGaAs optical wave guide with a band gap near the 1550
nm.
1550 nm optical carrier
Reference leg
Detectorbeam splitter
1550 nm optical carrier
Fiber Optic Interferometer
Rad sensor is inserted into one leg of a fiber-optic
interferometer.
X-Rays strike the rad sensor disturbing the waveguide’s electronic structure.
This causes a phase change in the interferometer. The process is believed
to occur with timescales < 100 fs.
X-Ray Photons
Point of interference X-Ray induced phase change observed as
an intensity modulation at point of interference
X-Ray measurements of the time structure of the SPEAR beam in January and March 2003 confirmed the devices x-ray sensitivity for LCLS applications.
time
phas
e
SPEARSingle electron
bunch mode
Mark Lowry,
R. M. Bionta
NIF Rad-Sensor Experimental Layout at SLACNIF Rad-Sensor Experimental Layout at SLAC
Ion chamber
attenuatorImaging cameraDiamond
PCDRadSensor
slit
R. M. Bionta
RadSensor Response to single-bucket fill pattern
•Fast rise•Long fall-time will be improved•Complementary outputs =>
•index modulation
Xray pulse history (conventional)
781 ns
Mark Lowry
R. M. Bionta
Significant Improvements in sensitivity are realized near the band edgeSignificant Improvements in sensitivity are realized near the band edge
Systematic spectral measurements of both index and absorption under xray illumination must be made to get a clear understanding of the sensitivity available
Absorption width = 0.01 nm
Absorption width = 1 nm
•Adding in x4 for QC enhancement we should detect a single xray photon at least 8x10-4 fringe fractions.
•If we allow for a cavity with finesse 10-100, this allow the development of a useful instrument
Data to date
= exciton abs peak widthFrom Gibbs, pg 137
Absorption edge at 1214 nm
Mark Lowry
R. M. Bionta
XRTOD Diagnostics TimelineXRTOD Diagnostics Timeline• FY04 – PED year 4
– PCMS certification - Jan 2004– Baseline Review - Aug 2003– Complete simulations of camera response to FEL and Spontanous– Prototype Windowless Ion Chamber / gas attenuator
• FY05 – PED year 3– FEE Detailed design
• FY06 - Start of Construction– FEE Build and test– NEH Design
• FY07– FEE Install– NEH Build and Test– FEH Design