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NSLS-II XBPM mini workshop, 2009
In-Situ Measurement of Heat-bumps at the CHESS A2 Beam-line
Peter Revesz, Alexander Kazimirov, Cornell University, CHESSIthaca, NY 14850
X-ray beam
Monochromator’s1st crystal
Beam footprint-- What is the heat bump?
-- What is the consequence of the heat bump?Distorted crystal – less flux
-- How to fight it?improved heat withdrawal: cryogenics, better substrate material
NSLS-II XBPM mini workshop, 2009
Thermalslope errors FWHM from (peak-to-valley) rocking curves at 20keV:FEA: (�) geometrical ray tracing: (�) Takagi–Taupintheory: (�) from and Experiment: (x) as a function of the total power.
Effect of high heat load on Si (111) performance
[5] J. Hoszowskaet.alNIM A 467–468 (2001) 631–634).
NSLS-II XBPM mini workshop, 2009
Mirror, mirror on the wall..
Distorted image…tells more about the mirrorthan about my face.
Reconstruct the change in surface relief of the mirror by analyzing the changes in the reflected image.
The Idea
NSLS-II XBPM mini workshop, 2009
The change in the angle of reflection ���where �r (μm) is shift of dot’sposition, and L (m) is the camera light source distance.
,Lr� ��
� ��
�
Measurement principle
�X�Y
The gradient map matrices for an array of dots:
Ly j i g
Lx j i gy x
��
��) , ( , ) , (
Slope vector field of a heat bump measured by using Centroidcalculations for each dot.[1] P.Reveszet.al.540,NIM-A 2-3, 470-9 (2005)
CCD
NSLS-II XBPM mini workshop, 2009
The problem:Given a vector field of gradients {gx, gy}Recover the surface Swhose gradient fieldbest approximates :
g�
g�
g S S�
� � min
Applying the divergence operator, we can transform this into a Poisson equation:
g S g S� �� �� � � � �� �� �
Measurementcentroids (gx, gy)
data saved
Matlab code to reconstruct surface,save calculated data
Surface reconstruction
NSLS-II XBPM mini workshop, 2009
The Moon: mare ridge south-west of Aristarchus
Surface reconstruction from shade. Shade is basically ~gradient of the reflected light (Lambertianreflection of light)
NSLS-II XBPM mini workshop, 2009
Shack-Hartmann wave front analyzer
…works using the same principle to measure aberration of the lens. It is compact device, so its accuracy is limited by the short image distance.
Lensletsare Fourier transform devices: X �
NSLS-II XBPM mini workshop, 2009
Experimental Setup
Camera on top of the monochromator
Inside the monochromatorViewportcrystal holderlight source
Light source
AstrovidCCD camera,55 mm telecentriclens
50 �m thick steel mask,4x4 in. area with holesø0.2mm, 1.5mm ain a rectangular grid withfluorescent light behind.
NSLS-II XBPM mini workshop, 2009
Centroidprogram screen images
Screen capture of the light dotsreflected form the crystal. A mm paper is placed on the crystal for scaling. The arrow indicates the beam direction
With this calibration we determinethe dot-spacing on the Si surface
Screen capture of the light dotsreflected form the crystal with the grid array used for CoGcalculations. Each CoGisshown as a small cross.
The gradient vector field measured with Centroidbefore X-ray exposure.[gx(i,j)= gy(i,j)=0 ]The surface is assumed to be flat.
d d’
NSLS-II XBPM mini workshop, 2009
Slope error calibration procedureto determine the correspondence between change in CoGand slope
Change in gradient field
Reconstructed surfaces [2]
051015202530
05
1015
200
0.02
0.04
0.06
0.08
X (mm)
si-15-calConstCalHV
Y (mm)
Height (m
icrons)
051015202530
05
1015
200
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
X (mm)
si-15-calConstCalHV
Y (mm)
Height (m
icrons)
No crystal tilt.50 ��Radian crystal tilt
Optical paths of the measurement
CCD
(un)tiltedcrystal
Light source
Virtual image
Instead of using absolute geometrical data
we use the gonoimeteras a calibrations tool
, /L r� �
�� ��
NSLS-II XBPM mini workshop, 2009
Slit:1x6 mm 171 mA, 90
010
2030
40
0
10
20
30-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
X (mm)
si171mA10x6mm9deg.txtHV #H(mRads)V(mRads)HxV=40x26 grids20.39sec
Y (mm)
Height (m
icrons)
0102030405060-0.5
0
0.5
1
1.5
X (mm)
Height (m
icrons)
0102030405060-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
X (mm)
Slope error (m
Rad)
Typical heat bump measurement resultCHESS A2 wiggler,
Total power on Si ~90W (Bolometric measurement)
NSLS-II XBPM mini workshop, 2009
01020304050
0.0
0.5
1.0
1.5
0
1020
Height (m
icrons)
Y (mm)
X (mm)
2 mm
010
2030
4050
0.0
0.5
1.0
1.5
0
510
1520
25
Height (m
icrons)
Y (mm)
X (mm)
10 mm
010
2030
4050
0.0
0.5
1.0
1.5
0
510
1520
25
Heigh t (m
icr ons)
Y (mm)
X (mm)
4 mm
010
2030
4050
0.0
0.5
1.0
1.5
0
510
1520
25
Z Axis
Y (mm)
X (mm)
6 mm
010
2030
4050
0.0
0.5
1.0
1.5
0
510
1520
25
Heigh t (m
icr ons)
Y (mm)
X (mm)
8 mm
010
2030
4050
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
0
510
1520
25
Heigh t (m
icron s)
Y (mm)
X (mm)
3x6 mm
010
2030
4050
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
0
510
1520
25
Heigh t (m
icron s)
Y (mm)
X (mm)
1.8x6 mm
010
2030
4050
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
0
510
1520
25
Heigh t (m
icron s)
Y (mm)
X (mm)
2.2x6 mm
010
2030
4050
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
0
510
1520
25
Heigh t (m
icron s)
Y (mm)
X (mm)
1x6 mm
01020304050
-1.0-0.50.00.51.01.52.02.5
0
1020
Heigh t (m
icrons)
Y (mm) X (mm)
0.6x6 mm
Upstream slit opening
Slit width
Slit height
X-ray beam incidence is along X-axis, tilt: 9o
NSLS-II XBPM mini workshop, 2009
051015202530354045
-0.20
-0.15
-0.10
-0.05
0.00
0.05
0.10
0.15
0.20
0.25
Slope error at varoius slit heights
Slope error (mR
adian)
Y Distance across the beam directions (mm)
0.6 mm 0.8 mm 1.0 mm 1.2 mm 1.4 mm 1.6 mm 1.8 mm 2.0 mm 2.2 mm 2.4 mm 2.6 mm 2.8 mm 3 mm
slit height
051015202530354045
0.0
0.5
1.0
1.5
2.0
2.5 Heat bump height at various slit heights
Bum
p height (microns)
Distance across the beam directions (mm)
0.6 mm 0.8 mm 1 mm 1.2 mm 1.4 mm 1.6 mm 1.8 mm 2 mm 2.2 mm 2.4 mm 2.6 mm 2.8 mm 3 mm
slit height
Heat bump on Si as a function of vertical slit opening
010203040506070
-0.20
-0.15
-0.10
-0.05
0.00
0.05
0.10
0.15
0.20
Slope error at various slit heights
Slope error (m
Radians)
Distance aling the beam direction (mm)
0.6 mm 0.8 mm 1.0 mm 1.2 mm 1.4 mm 1.6 mm 1.8 mm 2.0 mm 2.2 mm 2.4 mm 2.6 mm 2.8 mm 3 mm
Along the beam
Across the beam
010203040506070
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
Heat bump heights at various slit heights
Bum
p heigt (microns)
X Distance along the beam direction (mm)
0.6 mm 0.8 mm 1 mm 1.2 mm 1.4 mm 1.6 mm 1.8 mm 2 mm 2.2 mm 2.4 mm 2.6 mm 2.8 mm 3 mm
Slit height
Y
X
NSLS-II XBPM mini workshop, 2009
051015202530
-0.15
-0.10
-0.05
0.00
0.05
0.10
0.15
0.20
Slope error across Si at 9o 173 mA
Slope error (m
Radian)
distance across Si (mm)
2 mm 4 mm 6 mm 8 mm 10 mm
01020304050
-0.15
-0.10
-0.05
0.00
0.05
0.10
0.15
0.20
Slope error along the beam, 9o, 173 mA
Slope error (m
Radian)
distance along beam (mm)
2 mm 4 mm 6 mm 8 mm 10 mm
Heat bump on Si as a function of horizontal slit opening
Y
X
NSLS-II XBPM mini workshop, 2009
3D simulation of heat bumps using ANSYS
MATLAB code to generate 3D powerdeposition in Si (heatbumpgui.m)
•ANSYS Workbench with engineering model of Si and Holder with cooling,
•Setting ANSYS parameters,interfaces, meshing,
•Steady State Thermal Simulation andStatic Structural Simulation,
•Output surface deformation mesh
MATLAB code to generate Cartesian deformation surface from the ANSYS surface mesh
Matlab work with the help fromE.Windischand C. MacGahan
NSLS-II XBPM mini workshop, 2009
Simulation resultsSi, copper crystal holder with water cooling ANSYS simulation of
deformation at A2 beam at 171 mA, slit 1.x2 mm
Comparison of raw experimental data of slope error and bump height along the beam direction with ANSYS simulations.
The slope error from ANSYS surface was obtained by numerical differentiation of the surface along the maximum of the heat bump.
The experimental bump was obtained by surface recovery procedure from the gradient field.
footprint
01020304050607080
-0.10
-0.05
0.00
0.05
0.10
Slope error, Measurement vs. ANSYS171 mA, Slit:1x6mm, 9
o
Slope error (mR
adian)
X (mm)
ANSYS Experiment
010203040506070800.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
Slope error measurement Slit: 1x6 mm, 9o
Bum
p height (microns)
X (mm)
ANSYS Integrated raw
experimental slopes
footprint
NSLS-II XBPM mini workshop, 2009
Heat bump on multilayers
Why multilayers?•high/variable band-width•choice of substrate materials
Multilayers used at CHESSBeam- line
SourceSagittal focusin g
Usaged-spacing/ /materials
�E/E,%
Experimental techniques / application areas
A2W, e-y50%15 Å – Mo/B4C20 Å – Mo/B4C28 Å – W/B4C
0.30.61.9
In-situ diffraction/scatteringRadiographyMicrobeam fluorescenceMicrobeam diffraction
D1BM, e+n100%15 Å - W/B4C25 Å – W/C30 Å – Mo/B4C
0.551.71.4
Small- and Wide-angle scatteringFluorescence imagingRadiography
F3BM, e+n50%27 Å – W/C24 Å – W/B4C22 Å – Mo/B4C
2.20.80.7
Macromolecular crystallographyRadiation damage in protein crystals
G1W, e+y100%24 Å – W/B4C28 Å – W/B4C
1.31.9
Small-angle scatteringMicrobeam fluorescenceMacromolecular crystallography
G3W, e+y100%28 Å – W/B4C1.9In-situ diffraction/scattering
[4] A. Kazimirov et.al.J. Synchrotron Rad. (2006). 13, 204–210
NSLS-II XBPM mini workshop, 2009
X-ray flux through the 0.25 mm x 0.25 mm slit in the hutch as a function of the horizontal width of the white beam slit. The vertical size of the slit was 1 mm.
Heat bump on Multilayers
PropertySiCu(GlidCop�)
CVD SiC
thermalconductivity�, [W/m�K]
150365300
thermal expansion�, [x10-6 K-1]
2.516.62.2
figure of merit�/�[x10-6W/m]
604136
Young’s modulu[Gpa]
107124450
meltingtemperature,oC
141210832500
As more X-ray power is absorbed in the crystal heat bump develops that leads to flux loss.
[4] A. Kazimirov et.al.J. Synchrotron Rad. (2006). 13, 204–210
NSLS-II XBPM mini workshop, 2009
Heat bump on Multilayers (WB4C)
The effect of substrate material is quite evident.As a result of high heat conductivity and low thermal expansion coefficient of SiCthe heat bump is much reduced (by a factor of 3).
[4] A. Kazimirov et.al.J. Synchrotron Rad. (2006). 13, 204–210
NSLS-II XBPM mini workshop, 2009
Conclusion and Summary
[1] P. Revesz and J.A. WhiteAn X-ray beam position monitor based on the photoluminescence of helium gas Nuclear Instruments & Methods in Physics Research, Section A540, n 2-3, 470-9 (2005)
[2] P. Revesz, A.Kazimirovand I.BazarovIn-situ Visualization of Thermal Distortions of Synchrotron Radiation OpticsNuclear Instruments and Methods in Physics Research A 576(2007) 422–429
[3] P. Revesz, A.Kazimirovand I.BazarovOptical Measurement of Thermal Deformation of Multilayer Optics under Synchrotron RadiationNuclear Instruments and Methods in Physics Research A 582(2007) 142–145
[4] Alexander Kazimirov, Detlef-M. Smilgies, Qun Shen, XianghuiXiao, QuanHao, Ernest Fontes, Donald H. Bilderback, Sol M. Gruner, YuriyPlatonovband Vladimir V. MartynovMultilayer X-ray optics at CHESS,J. Synchrotron Rad. (2006). 13, 204–210
[5] J. Hoszowska, V. Mocella, L. Zhang, J.-S. Migliore, A.K. Freund, C. FerreroPerformance of synchrotron X-ray monochromators under heat load Part 3: Comparison between theory and experiment, Nuclear Instruments and Methods in Physics Research A 467–468 (2001) 631–634)
References
•A 3D In-Situ measurement of heat bumps on crystals and multilayers at high heatload has been developed.
•The experimental results show good agreement with ANSYS calculations.•Results show that for multilayers SiCsubstrate material is much favorable in comparison
with Si substrates.
Acknowledgement: Thanks due to Jim Savino for ANSYS simulations