x ray beam characterization richard m. bionta facility advisory committee meeting april 30, 2004...
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X Ray Beam Characterization
X Ray Beam Characterization
Richard M. BiontaFacility Advisory Committee Meeting
April 30, 2004
Richard M. BiontaFacility Advisory Committee Meeting
April 30, 2004
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
LCLS Commissioning
Measuring Gain vs z. Kick beam at z to stop FEL gain
Measure at end of undulator
Measure Spectra with resolution < = 5-15x10-4
But with bandwidth of 0.5%
Pulse length
…
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
FEL beam power level calculations
LL
DG
DGPsat3
16.1
28
1
3/2
c
KFK wp
fDG
DG
LL
1
1
3
1
f
a1d
a2a3
a4
a5a6
a7a8
a9a10
d
a11 a12
a13d
a14 a15
a16d
a17 a18
a19
LLRayleigh
DG
d
1
FELf
nDGL 41
EL
Photonw
eDG
14
Saturated power
FEL r parameter
Plasma frequency
Gain length parameterization
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Model FEL beam propagation as a single-mode gaussian
eee zRyxi
zw
yxzzkti
zzikw
kwptzyxE22
2
122
020
20 20
)(2,,,
kw
zzkwzw
0
0
2240 4
kzz
zzkwzR
0
0
2240 4
4
1
ew 20
LRayleighExitzz 0
wPp sat
2
000
2
4
fst 2330FEL modeled as a Gaussian beam in optics
Phase curvature function
Gaussian width Gaussian waist
Origin is one Rayleigh length in front of undulator exit
Amplitude is given in terms of saturated power level
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Check Gaussian with Ginger: A numerical FEL simulation
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
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
FEL Photon Spectra
0
w0 = 12558 /fsw0 - 50 / fs
3
x 1
017
w
att
sc
m2
w0 + 50 /fs
frequency
Po
we
r D
en
sit
yl= 0.15 nm
Time 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)
rms
BW
(%
)
0.8% E/E
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
FEL spatial FWHM downstream of undulator exit, l = 0.15 nmTransverse beam profile at
undulator 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)
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Ultimate output power uncertainTotal 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.
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Fastclosevalve
Slit A
PPS
13'Muonshield
Gas Attenuator
SolidAttenuator
Slit B
PPS
4'Muonshield
WindowlessIonChamber
Direct ImagerIndirect Imager
Spectrometer,Total Energy
PPS
AccessShaft
AccessShaft
ElectronBeam
PhotonBeam
Electron Dump
Front End Enclosure
NEH Hutch 1Front End Enclosure/
Hutch 1 Layout
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Diagnostics Commissioning
Start with Low Power SpontaneousSaturate DI, measure linearity with solid attenuatorsRaise power, Measure linearity of Calorimeter and Indirect imager. Cross calibrateTest Gas Attenuator
Raise Power, Look for FELin DI, switch to Indirect Imager when attenuator burns
SolidAttenuator
Slits
IonChamber
DirectImager
IndirectImager
Total energy
Gas Attenuator Slits
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Spontaneous radiation is a big background
0 < Ephoton < 1.2 MeV
400 keV < Ephoton < 1.2 MeVFar-field radiation pattern calculated by R. Tatchyn 400 m
from undulator exit.http://www-ssrl.slac.stanford.edu/lcls/x-rayoptics/documents/
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
FEE Layout
Gas Attenuator
SolidAttenuator
Slit B
PPS
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Windowless Gas Attenuator – 10 m system
Region of highest pressure
Gas Inlet
WindowVacuum pumps Vacuum pumps
Photon Energy eV
Gas Pressure, torr Transmission
800 N 1.65 10-4
8260 Ar 10 0.2
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Gas Attenuator – Windows
Open, tilted, nozzleHigh gas flow
Rotating slotsSynchronization
Plasma WindowGas flow
Photon Energy eV FEL FWHM mm
800 1.252
8260 0.176
Z = 90 m
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Gaussian Model Layout Code
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Gas Attenuator Issues
Beam size
Window
Blocking Spontaneous
Gas delivery and recovery in FEE tunnel
Physics instrumentation ( 1st experiment)
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Solid AttenuatorSolid Attenuator
Be, Li, and BBe, Li, and B44C attenuators C attenuators can tolerate FEL beam at E > can tolerate FEL beam at E > 2-3 keV2-3 keV
Linear/log configurationsLinear/log configurations
Multiple wheels allowing Multiple wheels allowing multiple configurationsmultiple configurations
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Solid Attenuator - Issues
Contamination of low Z attenuators
Damage and ES&H from damaged Be
Bleaching
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
NEH Hutch 1 Diagnostic systems
Windowless Ion
Chamber
Imaging Detector
Tank
Comissioning Tank
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Imaging Detector Tank
Direct Imager
Indirect Imager
Turbo pump
Space for
calorimeter
BeIsolation
valve
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Prototype Low Power imaging camera
CCDCamera
MicroscopeObjective
LSO or YAG:Ce crystal prism assembly
X-ray beam
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Photon Monte Carlo Simulations for predicting backgrounds and detector performance (at SPEAR)
4,0002,0000-2,000-4,000
4,000
3,000
2,000
1,000
0
-1,000
-2,000
-3,000
-4,000
-5,000
SPEAR source simulation
Visible photons
X, microns
Y, m
icro
ns
LSO25 Exit Z
403020100
450
400
350
300
250
200
150
100
50
0
MonteCarlo
Bend
LSO
5,0000-5,000-10,000
8,000
6,000
4,000
2,000
0
-2,000
-4,000
-6,000
-8,000
-10,000
5,0000-5,000-10,000
8,000
6,000
4,000
2,000
0
-2,000
-4,000
-6,000
-8,000
-10,000
X Ray Photons
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Simulation to predict performance at LCLS
Far-fieldSpontaniousDistribution
UndulatorOptics
Predict spectrum and spatial distribution in plane of camera
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
First check CCD by measuring Response 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.
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Photon Transfer Curve crcrcr PGtdGt ,Readout
2,,
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.
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Calibration 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 ,,,,, )(
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Calibration Coefficients for All Pixels
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Direct Imager Version 1 efficiency
CCD pixel size, microns 24 24 24 24 24 24 24 24Objective power 2.5 2.5 2.5 2.5 20 20 20 20Object Pixel Size 9.6 9.6 9.6 9.6 1.2 1.2 1.2 1.2Object FOV, mm 10 10 10 10 1 1 1 1Scintillator material LSO LSO LSO YAG LSO LSO LSO YAGCentral Wavelength (nm) 415 415 415 526 415 415 415 526Scintillator Thickness, microns 100 50 25 100 100 50 25 100Visible Photons/8 KeV interaction 248 248 248 66 248 248 248 66Solid angle efficiency % 0.05 0.05 0.05 0.05 0.7 0.7 0.7 0.7glue scintillator interface efficiency % 99.8 99.8 99.8 99.8 100 100 100 100prism glue interface efficiency % 98.5 98.5 98.5 98.5 98.5 98.5 98.5 98.5prism transmission efficiency % 100 100 100 100 100 100 100 100mirror reflection efficiency % 94 94 94 97.8 94 94 94 97.8Objective transmission efficiency % 99.7 99.7 99.7 99.9 99.7 99.7 99.7 99.9CCD Quantum Deficiency % 62.4 62.4 62.4 71.3 62.4 62.4 62.4 71.3Photo electrons/interacting x-ray 0.068 0.068 0.068 0.021 0.955 0.955 0.955 0.304Photosn/Gray 74 74 74 238 5 5 5 16Scintillator efficiency % 100 98.4 87.2 94.6 100 98.4 87.2 94.6Time to fill well at SSRL bend, minutes 3.1 3.2 3.6 10 14 14 16 47Attenuation needed at LCLS to fill well 2.E-04 2.E-04 2.E-04 6.E-04 7.E-04 8.E-04 9.E-04 2.E-03
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Camera Sensitivity Measurements at SPEAR 10-2
Horizontal Vertical
<----10 mm----->
Photon Rate at Camera
Sum-of-Greys/Second3.000E+102.000E+101.000E+100.000E+00
#P
hoto
ns/S
ec
1.40E+12
1.30E+12
1.20E+12
1.10E+12
1.00E+12
9.00E+11
8.00E+11
7.00E+11
6.00E+11
5.00E+11
4.00E+11
3.00E+11
2.00E+11
1.00E+11
0.00E+00
Sum of gray levels
Ion Chamber Photon rate
attenuator
Imaging camera
Ion chamber
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Measured and predicted sensitivities in fair agreement
Measured and Predicted Sensitivity
020406080
100120140160180
0 10000 20000 30000
Photon Energy, eV
Ph
oto
ns/g
ray
Pred Ver 1
Meas Ver 1
Meas Ver 2
Pred Ver 2
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Camera Resolution ModelSource Dobj Dimg Objective Crystal Rdiffract Rdepth RSourceX RSourceY TotalX TotalY
SPEARBend 18.670 0.050 20x YAG100 3.1 8.4 2.1 0.5 9.2 8.9SPEARBend 18.670 0.050 20x LSO100 2.5 8.4 2.1 0.5 9.0 8.7SPEARBend 18.670 0.050 20x LSO50 2.5 4.2 2.1 0.5 5.3 4.9SPEARBend 18.670 0.050 20x LSO25 2.5 2.1 2.1 0.5 3.9 3.3SPEARBend 18.670 0.050 20x YAG20 3.1 1.7 2.1 0.5 4.1 3.6SPEARBend 18.670 0.050 20x YAG5 3.1 0.4 2.1 0.5 3.8 3.2
SPEARBend 18.670 0.050 2.5x Zeiss YAG100 9.6 2.8 2.1 0.5 10.2 10.0SPEARBend 18.670 0.050 2.5x Zeiss LSO100 7.5 2.8 2.1 0.5 8.3 8.0SPEARBend 18.670 0.050 2.5x Zeiss LSO50 7.5 1.4 2.1 0.5 8.0 7.7SPEARBend 18.670 0.050 2.5x Zeiss LSO25 7.5 0.7 2.1 0.5 7.9 7.6SPEARBend 18.670 0.050 2.5x Zeiss YAG20 9.6 0.6 2.1 0.5 9.8 9.6SPEARBend 18.670 0.050 2.5x Zeiss YAG5 9.6 0.1 2.1 0.5 9.8 9.6
SPEARBend 18.670 0.050 5x Zeiss YAG100 3.8 6.9 2.1 0.5 8.2 7.9SPEARBend 18.670 0.050 5x Zeiss LSO100 3.0 6.9 2.1 0.5 7.8 7.6SPEARBend 18.670 0.050 5x Zeiss LSO50 3.0 3.5 2.1 0.5 5.0 4.6SPEARBend 18.670 0.050 5x Zeiss LSO25 3.0 1.7 2.1 0.5 4.1 3.5SPEARBend 18.670 0.050 5x Zeiss YAG20 3.8 1.4 2.1 0.5 4.6 4.1SPEARBend 18.670 0.050 5x Zeiss YAG5 3.8 0.3 2.1 0.5 4.4 3.8
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Camera Resolution in qualitative agreement with models
1.5 mm
1.1 mm
1.5 mm
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Issues
Vacuum Operation
Low Photon Energy Performance
Noise levels and Format of 120 Hz Readout CCDs
Afterglow in LSO
High Energy Spontaneous Background
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Be Reflectivity at 8.267 keV
1.E-06
1.E-04
1.E-02
1.E+00
0 0.5 1 1.5 2 2.5
Angle, deg
Ref
lect
ivit
y
Indirect, high power imaging system
Be MirrorBe Mirror
Be Mirror angle provides "gain" adjustment Be Mirror angle provides "gain" adjustment over several orders of magnitude.over several orders of magnitude.
Cuts off high energy spontaneousCuts off high energy spontaneous
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Multilayer allows higher angle, higher transmission and energy selection, 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
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Indirect Imager Mirror sizes
Photon Energy eV
FEL FWHM mm
Mirror Length mm
Normal Incidence
dose to Be, eV/atom
800 1.222 70.0 0.015
8260 0.170 9.7 0.000
• = 1.0 deg• Z = 105 m
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Indirect imager issues
Calibration
Mirror roughness
Tight camera geometry
Compton background
Vacuum mechanics
Making mirror thin enough for maximum transmission
Ceramic multilayers?
Use as an Imaging Monochrometer
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Windowless Ion Chamber for monitoring position and intensity
Measures intensity using x-ray gas interactions
Windowless for operation at low photon energiesOpen nozzel
Rotating slots
Plasma window
Crude imaging may be possibleAs a drift chamber
As a Quad cell
As a Fluorescent Imager
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Micro Strip version
Differentialpump
Differentialpump
Cathodes
Segmented horizontal
and vertical anodes
Isolation valve with
Be windowWindowless
FEL entry
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Windowless ion chamber issues
Windowless operation issues (gas attenuator)
Beam sizeWindowBlocking SpontaneousGas delivery and recovery in Hutch
Choice of readoutPulsed operation
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Commissioning Diagnostics Tank
Intrusive measurements behind attenuatorMeasurements
Photon energy spectraTotal energySpatial coherenceSpatial shape and centroidDivergence
R&DPulse length
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Commissioning diagnostic tank
ApertureStage
“Optic”Stage
Detector and attenuatorStage
Rail alignment StagesRail
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Total Energy
Crossed aperturesOn positioning stages
absorber
Temperaturesensor
AttenuatorScintillator
Absorber Dose 2 x FWHM 4 x attn lngtheV/atom microns microns
0.8 KeV Be 0.02 1918 208 KeV Si 0.12 338 310
Poor ThermalConductor
HeatSink
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Total energy issues
120 Hz operation
Segmentation
Non-standard materials (Be)
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Photon Spectra Measurement
ApertureStage
Crystals or gratings for 3Photon energies
Detector and attenuatorStage
X ray enhanced linear array and stage
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Sputtered-sliced multilayer gratings as high bw spectrometersSputtered-sliced multilayer gratings as high bw spectrometers
5-m-thick Mo/Si multilayer (d=200 Å) on Si wafer substrate. Thinned and polished to a 10- m-thick slice
SEM image of Mo/Si multilayer
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Spectrometer Issues
How to achieve 10-4 resolution over a 0.5% bandwidth shot-to-shot?
Dynamic range
Designs for low divergence beam
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Pulse length measurement - 233 fsec!
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,
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
NIF Rad-Sensor Experimental Layout at SLAC
Ion chamber
attenuatorImaging cameraDiamond
PCDRadSensor
slit
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
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
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Significant 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
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Pulse length sensor issues
Significant R&D needed in"magic material" that converts between x-ray and optical laser light
Acquisition and recording systems with fs resolution
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
XRTOD Diagnostics TimelineFY04 – PED year 4
Complete simulations of camera response to FEL and SpontanousR&D on Ion Chamber, gas attenuator, and spectrometer
FY05 – PED year 3FEE Detailed design
FY06 - Start of ConstructionFEE Build and testNEH Design
FY07FEE InstallNEH Build and TestFEH Design
FY08NEH InstallFEH Build and Test
FY09 - Start of Operation
Richard M. Bionta
X-Ray Beam Characterization [email protected]
April 29, 2004
Diagnostics Issues
Large number of independent deliverables
Source for testing damage issues does not exist
Funding Profile means considerable design work still ahead
But, the resources are available for success.