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-7405Eng-48 and by Stanford University, Stanford Linear Accelerator Center under contract No. DEAC03-76SF00515.
WBS 1.5 X-Ray Transport, Optics, &
Diagnostics (XTOD)
• Provides unobstructed
vacuum path from end of
undulator to end of FEH
FEH - Far
Experimental
Hall
Tunnel
NEH - Near
Experimental
Hall
FEE
Front End Enclosure
LCLS X-Ray Beam
• Flux densities in NEH
will be the highest
available
• Flux densities in FEH
will be similar to
synchrotron facilities
R. M. Bionta
X-ray Transport, Optics, and Diagnostics
Layout
Each 13 m long hutch has two vacuum tanks for experimental and facility hardware
NEH
FEH
FEE
Front End
Enclosure
Diagnostics
Slits
Attenuators
Tunnel
FEL Measurements
Experiments
& Experiments:
Optics
Compression
Structual Bio
Monochrometer
Spectra
Nano-scale
Pulse-Split & Delay
Coherence
Femtochem
Diagnostics
Pulse Length
Low Energy
Order Sorting
Mirror
Experiments:
Optics
Warm Dense Matter
Atomic Physics
R. M. Bionta
Beam Models
FEL beam power levels
 K  p wF 1K 
FEL r parameter   

 8 c 2  
2/3
Saturated Psat  1.6    L
power
L
G1D
G 3D
Gain length parameterization
L
L
G1 D
G 3D
fa1 d

1
1 
Plasma
frequency p 
4    r e c  ne
2

f
a2
a4
a6
a8 a9
a11 a12
a14 a15
a17 a18 a19
a3  a5  a7   a10 d

a13 d

a16 d


Correct definition of h parameters
  L
L
G1D
d
Rayleigh
  L
G1 D
 4    n
 
f
FEL




4    LG1D  e
 E
w
Photon
R. M. Bionta
Spatial-temporal shape
FEL can be modeled as a Gaussian beam in optics
0  t  233  fs
2 y
2
1 ix 2  y
i t  k  z  z 0 
x

w
0k
2
E  x, y , z , t   p  2
e
 e w z   e2 R  z 
w0  k  2  i  ( z  z0)
2
Phase curvature function
Gaussian width
w z  
4
2
1 w0  k  4   z  z0 
Rz   
4
 z  z0   k
4
2
w0  k  4   z  z 0 
2

2
2
w0  2   e
Gaussian waist
w0  k
z0  z Exit  LRayleigh 
Origin is one Rayleigh length in front of undulator exit
Amplitude is given in terms of saturated power level
p
2
 4
P
sat
   w 
2
0
0
0
R. M. Bionta
LCLS Fundamental Electric Field
and Dose Equations

Gaussian Electric Field:
With origin
z0  zexit  LR  
x2  y2 




 w  z  z 2 

p  w02  k
0



E ( x, y, z, t )  eitt  e ik ( z  z0 ) 

e

e
2
 w0  k  2  i  ( z  z0 )
waist
w  z  z0  
2
z  z0 2  2  w2
 2  w02


2
2 
1  ik  x  y 
2 R zz  
c
0 
4
2
Phase R z  z   z  z   1  w0  k
c
0
0
Curvature
4 z  z0 
0

1 x2  y2
N electron  2 
e
Waist at origin matches electron distribution  electron 
2     e2
 e2

gives
w0  2   e
 x2  y2 

 2
 w  z  z 2 
w02
0


E  bunch  p   bunch 

e
2
wz  z0 
2
Electric field intensity x duration
Matches photon distribution
Peak photon density
Dose
2
 photon x, y , z   Apeak z   e
Apeak z  
2
2

  2 x  y
2


w
z

z
0





with
N photon 
Psat  bunch
E photon
2  N photon
  wz  z0 2
Dose  E photon   photon   photoion
R. M. Bionta
FEL parameters at absorber
exit, z = 65 meters
Electron kinetic energy,T
Fundamental wavelength,
Fundamental photon energy, E photon
FEL saturated power, Psat
Bunch duration,  bunch
z
Position from undulator center,
Fundamental transverse FWHM
A
Peak photon density, peak
Minimum
4.54
1.50
0.828
Maximum
14.35
0.15
8.271
Units
GeV
nm
KeV
11.0
9.6
Gwatt
233
233
fsec
65.00
232.7
315
65.00
86.7
199
m
micron
photons/nm2
And at other locations:
FEL Photon Energy:
Z
m
50.0
Undulator Exit
59.9
Slit
63.7
Absorber Center
82.0
Mirror Tank
84.4
Crystal
100
Experimental Area
0.828 KeV
FWHM
Apeak
micron
/nm2
79
2351
176
532
217
356
414
99
440
88
610
46
8.27 KeV
FWHM
Apeak
micron
/nm2
67
290
77
225
81
205
102
134
105
128
124
93
R. M. Bionta
Ginger provides complex
Electric Field envelope at
undulator exit
Data in the form of
N  768  3  2
8
radial distributions
of complex numbers
representing the
envelope of the
Electric Field at the
undulator exit.
Each radial distribution has
NR  47
radial points.
t  i  t
i  1..N
0
150
Electric Field Envelope Power Density vs time
at R = 0
Samples are separated in time by
wavelengths.
Time between samples is
t 
watts/cm2
n  16
R, mm
n
c
R. M. Bionta
Tools for manipulating GINGER
output
Viewer
GINGER output:
Tables of electric field values
at undulator exit
at different times
t  i  t
viewer
i  1..N
0
150
R, mm
Transformation to
Frequency Domain
Power Density
Time
Domain
Frequency
Power DensityDomain
watts
x 1015 c m2
1.94
0
x 1017
watts
c m2
Temporal 1.73
Transform
0
w0-400/fs
2
4
0
6
Time, femtoseconds
w0
w0+400/fs
frequency
Power Density
Power Density
watts
x 1015 c m2
1.94
x 1017
watts
c m2
Propagation
to arbitrary
z
Spatial 1.73
Transform
0
-150
0
150
Transverse position, microns
0
-325
-10
304
Wavenumber, mm-1
R. M. Bionta
FEL spatial FWHM downstream
of undulator exit, l = 0.15 nm
Transverse beam profile at
undulator exit
FWHM vs. z at l = 0.15 nm
500
Transverse beam profile
15 m downstream of
undulator exit
FWHM, microns
400
300
Ginger
(points)
200
Gaussian Beam
(line)
100
0
0
100
200
300
distance from undulator exit, meters
R. M. Bionta
Total power at undulator exit
Total FEL Power
35.00
•10 Ginger simulations were run at
different electron energies but with
fixed electron emittance through 100
meter LCLS undulator.
30.00
Giga-Watts
Ginger simulations
25.00
•The Ginger runs at the longer
wavelengths were not optimized,
resulting in significant postsaturation effects. Results at longer
wavelengths carry greater
uncertanty.
20.00
Theoretical FEL
saturation level
15.00
10.00
5.00
0.00
0.00
0.50
1.00
1.50
2.00
wavelength, nm
R. M. Bionta
RMS Bandwidth
l= 0.15 nm
Time Domain
l= 0.15 nm
Frequency Domain
rms BW (%)
rms BW (%) vs wavelength
(nm)
0.40
0.30
0.20
0.10
0.00
0.0
Power Density
watts
x 1017
c m2
3
1.0
2.0
wavelength (nm)
0
w0 - 50 / fs
w0 = 12558 /fs
frequency
w0 + 50 /fs
R. M. Bionta
FWHM vs. wavelength at 0, 75
and 300 meters
FWHM vs wavelength at selected distances from undulator
exit
1000
FWHM, microns
300 meters
750
500
Ginger, 0 m
Gauss, 0 m
Ginger, 75 m
Gauss, 75 m
Ginger, 300 m
Gauss, 300 m
75 meters
250
0 meters
0
0.0
0.5
1.0
wavelength, nm
1.5
R. M. Bionta
We can confidently calculate the dose to transmissive
optics.
Transmissive Dose Model
Reflective Dose Model
electron
X-ray
Photon
atoms
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.
R. M. Bionta
Dose / Power Considerations
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 spontaneous
R. M. Bionta
Detailed Spontaneous, in progress
R. M. Bionta
E > 400 KeV
R. M. Bionta
FEE Instrumentation
R. M. Bionta
Front End Enclosure Layout
PPS
Diagnostics
Slits
Solid Attenuator
40m
WestFace
Near Hall
Gas Attenuator
33m
WestFace
Dump
Windowless
Ion Chamber
Diagnostics
10.5 m
Slits
Slow valve
Fast valve
Fixed Mask
Pump
Valve
Pump
0 m
End of Undulator
16.226 m
Eastface Last Dump Mag
Westface front End Enclosure
R. M. Bionta
Adjustable High-Power Slits
Intended to intercept
spontaneous beam, not FEL beam
-- but will come very close, so
peak power is an issue
Two concepts being pursued for
slit jaws
Treat jaw as mirror (high-Z
material)
Treat jaw as absorber (low-Z
material
Either concept requires long
jaws with precision motion
Mechanical design based on
SLAC collimator for high-energy
electron beam
R. M. Bionta
Front End Diagnostic Tank
Solid Filter Wheel
Assembly
ION Chamber
Be
Isolation
valve
Direct Imager
Indirect
Imager
Space
for
calorimeter












Turbo pump
R. M. Bionta
Prototype LCLS X-Ray imaging camera
CCD
Camera
Microscope
Objective
X-ray beam
X-ray beam
LSO or YAG:Ce crystal prism assembly
R. M. Bionta
Indirect Imager
Be Mirror
Be Mirror Reflectivity at 8 KeV
1
1.E+00
0
0.1
1.E-01
1.E-02
0.001
1.E-03
R
0.01
0.0001
Be Mirror Reflectivity
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Be Mirror angle provides "gain" adjustment
over several orders of magnitude
1.E-04
1.E-05
1.E-06
1.E-07
1.E-08
Angle (degrees)
R. M. Bionta
Multilayer allows higher angle and higher
transmision but high z layer gets high dose
Be Mirror needs grazing incidence, camera close to beam
Single high Z layer tamped by Be may hold together
R. M. Bionta
First check CCD by measuring
Response Equation Coefficients
d r ,c  G  (Qr ,c  Lr ,c  DC r ,c )  t  Pr ,c
d r ,c
Digitized gray level of pixel in row r, column c.
Electronic gain in units grays/photo electron.
G
Lr ,c   QE ( )   r ,c ( )  d Signal in units photo electrons.
Qr ,c
Pixel Sensitivity non-uniformity correction.
DC r ,c
Pixel Dark Current in units photo electrons/msec.
Pr ,c
Pixel fixed-pattern in units grays.
t
Integration time in units msec.
R. M. Bionta
Photon Transfer Curve

2
r ,c
d r ,c (t ) 

2
r ,c

(t )  G  dr ,c (t )  
(t ) 
1
N pixels
  d r ,c (t )
r ,c
1
N pixels  1
2
Readout
 G  Pr ,c

Temporal mean gray level of
pixel r,c.
  d r ,c (t )  d r ,c (t )
2
r ,c
Temporal gray level
fluctuations of pixel r,c.
R. M. Bionta
Calibration Data for one pixel
d r ,c  G  (Qr ,c  Lr ,c  DC r ,c )  t  Pr ,c
Mean gray vs. time
70000
60000
Mean Gray
50000
40000
30000
20000
10000
0
0
1000
2000
3000
4000
5000
6000
7000
time, milliseconds
 2 r ,c (t )  G  dr ,c (t )   2 Readout  G  Pr ,c 
Sigma Squared Vs. Mean
Sigma Squared
12000
10000
8000
6000
4000
2000
0
0
10000 20000 30000 40000 50000 60000 70000
Mean gray
R. M. Bionta
Calibration Coefficients for All Pixels
R. M. Bionta
Photon Monte Carlo Simulations for predicting lens and
camera performance
LSO
4,000
3,000
Y, microns
2,000
Monte
Carlo
1,000
0
-1,000
Bend
-2,000
LSO25 Exit Z
-3,000
-4,000
450
-5,000
400
-4,000
-2,000
0
2,000
8,000
4,000
350
6,000
300
X, microns
4,000
250
200
X Ray Photons
150
SPEAR source
simulation
2,000
0
100
-2,000
50
-4,000
0
0
10
20
30
40
-6,000
-8,000
-10,000
-10,000
-5,000
0
5,000
8,000
6,000
4,000
2,000
0
Visible photons
-2,000
-4,000
-6,000
-8,000
-10,000
-10,000
-5,000
0
5,000
R. M. Bionta
Direct Imager Version 1 efficiency
CCD pixel size, microns
Objective power
Object Pixel Size
Object FOV, mm
Scintillator material
Central Wavelength (nm)
Scintillator Thickness, microns
Visible Photons/8 KeV interaction
Solid angle efficiency %
glue scintillator interface efficiency %
prism glue interface efficiency %
prism transmission efficiency %
mirror reflection efficiency %
Objective transmission efficiency %
CCD Quantum Deficiency %
Photo electrons/interacting x-ray
Photosn/Gray
Scintillator efficiency %
Time to fill well at SSRL bend, minutes
Attenuation needed at LCLS to fill well
24
2.5
9.6
10
LSO
415
100
248
0.05
99.8
98.5
100
94
99.7
62.4
0.068
74
100
3.1
2.E-04
24
2.5
9.6
10
LSO
415
50
248
0.05
99.8
98.5
100
94
99.7
62.4
0.068
74
98.4
3.2
2.E-04
24
2.5
9.6
10
LSO
415
25
248
0.05
99.8
98.5
100
94
99.7
62.4
0.068
74
87.2
3.6
2.E-04
24
2.5
9.6
10
YAG
526
100
66
0.05
99.8
98.5
100
97.8
99.9
71.3
0.021
238
94.6
10
6.E-04
24
20
1.2
1
LSO
415
100
248
0.7
100
98.5
100
94
99.7
62.4
0.955
5
100
14
7.E-04
24
20
1.2
1
LSO
415
50
248
0.7
100
98.5
100
94
99.7
62.4
0.955
5
98.4
14
8.E-04
24
20
1.2
1
LSO
415
25
248
0.7
100
98.5
100
94
99.7
62.4
0.955
5
87.2
16
9.E-04
24
20
1.2
1
YAG
526
100
66
0.7
100
98.5
100
97.8
99.9
71.3
0.304
16
94.6
47
2.E-03
R. M. Bionta
Camera Sensitivity Measurements at
SPEAR 10-2
attenuator
Ion chamber
Imaging camera
Photon Rate at Camera
Horizontal
Vertical
1.40E+12
1.30E+12
1.20E+12
1.10E+12
1.00E+12
#Photons/Sec
9.00E+11
8.00E+11
7.00E+11
Ion Chamber
Photon rate
Sum of gray levels
6.00E+11
5.00E+11
4.00E+11
3.00E+11
2.00E+11
1.00E+11
0.00E+00
0.000E+00
<----10 mm----->
1.000E+10
2.000E+10
3.000E+10
Sum-of-Greys/Second
Fit to n  b  G   g r ,c
In front of camera window
At scintillator
Item
Fit
Error
Units
Item
Fit
Error
Units
G
39.4
0.1
/g
G
31.1
0.1
/g
b
-1.1x1010
0.3x1010

b
-0.9x1010
0.3x1010

R. M. Bionta
Measured and predicted
sensitivities in fair agreement
Photons/gray
Measured and Predicted Sensitivity
180
160
140
120
100
80
60
40
20
0
Pred Ver 1
Meas Ver 1
Meas Ver 2
Pred Ver 2
0
10000
20000
30000
Photon Energy, eV
R. M. Bionta
Camera Resolution Model
Source
Dobj
Dimg Objective
Crystal
Rdiffract
Rdepth
SPEARBend
SPEARBend
SPEARBend
SPEARBend
SPEARBend
SPEARBend
18.670
18.670
18.670
18.670
18.670
18.670
0.050
0.050
0.050
0.050
0.050
0.050
SPEARBend
SPEARBend
SPEARBend
SPEARBend
SPEARBend
SPEARBend
18.670
18.670
18.670
18.670
18.670
18.670
SPEARBend
SPEARBend
SPEARBend
SPEARBend
SPEARBend
SPEARBend
18.670
18.670
18.670
18.670
18.670
18.670
RSourceX RSourceY
TotalX
TotalY
20x
20x
20x
20x
20x
20x
YAG100
LSO100
LSO50
LSO25
YAG20
YAG5
3.1
2.5
2.5
2.5
3.1
3.1
8.4
8.4
4.2
2.1
1.7
0.4
2.1
2.1
2.1
2.1
2.1
2.1
0.5
0.5
0.5
0.5
0.5
0.5
9.2
9.0
5.3
3.9
4.1
3.8
8.9
8.7
4.9
3.3
3.6
3.2
0.050
0.050
0.050
0.050
0.050
0.050
2.5x Zeiss
2.5x Zeiss
2.5x Zeiss
2.5x Zeiss
2.5x Zeiss
2.5x Zeiss
YAG100
LSO100
LSO50
LSO25
YAG20
YAG5
9.6
7.5
7.5
7.5
9.6
9.6
2.8
2.8
1.4
0.7
0.6
0.1
2.1
2.1
2.1
2.1
2.1
2.1
0.5
0.5
0.5
0.5
0.5
0.5
10.2
8.3
8.0
7.9
9.8
9.8
10.0
8.0
7.7
7.6
9.6
9.6
0.050
0.050
0.050
0.050
0.050
0.050
5x Zeiss
5x Zeiss
5x Zeiss
5x Zeiss
5x Zeiss
5x Zeiss
YAG100
LSO100
LSO50
LSO25
YAG20
YAG5
3.8
3.0
3.0
3.0
3.8
3.8
6.9
6.9
3.5
1.7
1.4
0.3
2.1
2.1
2.1
2.1
2.1
2.1
0.5
0.5
0.5
0.5
0.5
0.5
8.2
7.8
5.0
4.1
4.6
4.4
7.9
7.6
4.6
3.5
4.1
3.8
R. M. Bionta
Camera Resolution in qualitative
agreement with models
1.1 mm
1.5 mm
1.5 mm
R. M. Bionta
Camera Resolution Quantitative Data
Analysis in progress
R. M. Bionta
Micro Strip Ion Chamber
Cathodes
Windowless
FEL entry
Differential
pump
Segmented
horizontal
and
vertical
anodes
Isolation valve
with
Be window
Differential
pump
R. M. Bionta
Gas Attenuator
For use when solid absorber risks damage (low-E FEL, front end)
Windowless, adjustable attenuation
Can provide up to 4 orders of magnitude attenuation
R. M. Bionta
Solid Attenuator
B4C attenuators can tolerate
FEL beam at E > 4 keV in FEE,
and at all energies in
experimental hutches
Linear/log configurations
Can be wedged in 2
dimensions for continuously
variable attenuation
Translation stages provide
precision X and Y motion
R. M. Bionta
Missing
• Predicted performance of direct and
indirect imager for Spontanous vs. I,
and FEL vs. Power
• Calculations of linearity and signal
levels in Ion chamber
• Integration with FEE + Beam Dump
floor plan
R. M. Bionta
Commissioning Diagnostic Tank
R. M. Bionta
Commissioning Diagnostics
Measurements
– Total energy
– Pulse length
– Photon energy spectra
– Spatial coherence
– Spatial shape and centroid
– Divergence
R. M. Bionta
Commissioning diagnostic tank
Aperture
Stage
“Optic”
Stage
Rail
Detector and attenuator
Stage
Rail alignment
Stages
R. M. Bionta
Costing based on SSRL 2-3 set
up
R. M. Bionta
Total Energy
Temperature
sensor
Poor Thermal
Conductor
absorber
Heat
Sink
Crossed apertures
On positioning stages
Attenuator
Scintillator
Absorber
0.8 KeV
8 KeV
Be
Si
Dose 2 x FWHM 4 x attn lngth
eV/atom microns
microns
0.02
1918
20
0.12
338
310
R. M. Bionta
Photon Spectra Measurement
Aperture Crystal (8KeV)
Stage Grating (0.8 KeV)
Stage
Detector and attenuator
Stage
X ray enhanced linear array and stage
R. M. Bionta
Spatial Coherence Measurement
Slits
Stage
Detector and attenuator
Stage
Array of double slits
R. M. Bionta
Spatial shape, centroid , and
divergence
•A1
•FEE:
FFTB
Diagnostic
Tanks
FEE 1 & 3:
•A2
•A4
HALL A
Diagnostic
Tank
A1-1
Commissioning
Diagnostic
Tank
A4-1
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
length 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
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 measurements of the time structure of the
SPEAR beam in January and March 2003 confirmed
the devices x-ray sensitivity for LCLS applications.
Rad sensor is inserted into
one leg of a fiber-optic
interferometer.
1550 nm optical carrier
beam
splitter
SPEAR
Single electron
bunch mode
Reference
leg
Detector
Point of
interference
Fiber Optic Interferometer
time
X-Ray induced phase change observed as
an intensity modulation at point of
interference
Mark Lowry, R. M. Bionta
NIF Rad-Sensor Experimental Layout at SLAC
Imaging camera RadSensor
slit
Ion chamber
Diamond
PCD attenuator
R. M. Bionta
RadSensor Response to single-bucket fill pattern
Xray pulse history (conventional)
•Fast rise
•Long fall-time will be improved
781 ns
•Complementary outputs =>
•index modulation
Mark Lowry R. M. Bionta
Significant Improvements in sensitivity are realized near the band edge
= exciton abs peak width
Absorption width = 0.01 nm
From Gibbs, pg 137
•Adding in x4 for QC
enhancement we should
detect a single xray photon at
least 8x10-4 fringe fractions.
Absorption width = 1 nm
Data to date
Absorption edge at 1214 nm
•If we allow for a cavity with
finesse 10-100, this allow the
development of a useful
instrument
Systematic spectral measurements of both index and absorption under xray
illumination must be made to get a clear understanding of the sensitivity available
Mark Lowry R. M. Bionta
XRTOD 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
•
FY08
– NEH Install
– FEH Build and Test
•
FY09 - Start of Operation
R. M. Bionta
Startup Procedure
R. M. Bionta
FEE Diagnostics Comissioning
Ion
Chamber
Attenuator
Ion
Chamber
Attenuator
Gas Attenuator
Direct
Imager
Indirect
Imager
Direct
Imager
Indirect
Imager
• Start with Low Power Spontaneous
– Saturate DI, measure linearity with solid
attenuators
– Test Gas Attenuator
• Raise Power, Look for FEL
– in DI, switch to Indirect Imager when attenuator
burns
– Move behind Gas Attenuator
– Move to Comissioning Diagnostic Tank
R. M. Bionta
Summary
• 3 detector designs for flexibility
• Move back if necessary
• Bring on the beam!
R. M. Bionta