lcls-ii project and beamline instruments: mechanical ... · 10/18/2016 · lcls-ii project and...
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October 18, 2016NSLS-II Engineering Seminar Series
LCLS-II project and beamline instruments:mechanical engineering challenges
L. Zhang
LCLS, SLAC National Accelerator Laboratory2575 Sand Hill Road, Menlo Park, CA, 94025, United States
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Co-workers at LCLS/SLAC
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
• L. Amores• D. Cocco• C. Hardin• J. James• N. Kelez• J. Krzywinsk• D. Morton• D. Schafer• V. Srinivasan now India• P. Stefan• R. Whitney
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Outline of the presentation
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Ø Introduction§ LCLS, LCLS-II project§ X-ray Transport and Experimental Systems (XTES)§ Beamline instruments
Ø Mechanical engineering challenges in XTESØ Attenuators, beam stoppers and beam collimatorsØ X-ray optics and KB mirror systems§ Optics cooling§ Flat mirror§ Bendable KB mirror systems
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LCLS vs. LCLS-II
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
NEH
FEH
LCLS office
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LCLS vs. LCLS-II
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
4 GeV SC Linac
LCLS LCLS-II
Accelerator (Linac) Copper Linac (3-15 GeV)Superconducting Linac (4 GeV)+ Copper Linac (3-15 GeV)
Undulator Fixed/Tapered gap SXU + HXU: variable gap
Repetition rate 120 Hz ~ 1 MHz
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LCLS vs. LCLS-II
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
LCLS-I HXU - Cu HXU - SC SXU - SC SXU – Cu
Photon Energy Range (keV) 0.25 - 12.8 1 - 25 1 - 5 0.25 - 1.3 0.25 - 6
Repetition Rate (Hz) 120 120 929,000 929,000 120
Per Pulse Energy (mJ) ~ 4 ~ 4 ~ 0.2 ~ 1 ~ 7
Max. av. power (W) 0.48 0.48 200 600 0.8
Photons/Second ~ 1014 ~ 1014 ~ 1016 ~ 1017 ~ 1014
LCLS-II-HE: à 13 keV (≥100 kHz, SC Linac)
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X-ray Transport & Experimental Systems (XTES)
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Ø X-ray beam transport system§ Diagnostics and components
Ø X-ray experimental system§ X-ray instruments
Ø X-ray Optics
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XTES Schematic Layout
LCLS-II DOE Review, October 12-14, 2016
SXR BranchSXR Branch
HXR BranchHXR Branch
• X-ray optics- Offset (flat) mirrors
• X-ray diagnostics- Beam imagers- (Gas) energy monitors- HXR spectrometer- HXR K-monochromator
• X-ray components- (Gas and solid) attenuators- Stoppers, collimators,
apertures/slits• New SXR endstation
- KB focusing optics- (Gas) photon dump
Existing LCLS
Upgraded by LCLS-II
Development (not in scope)
New LCLS-II
FEE
NEH
EBD
Courtesy Y. Feng
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X-ray instrument plans for LCLS-II
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
• 7 instruments fed by a single undulator at present• 9 instruments available for LCLS-II
NEH 1.1: Atomic, Molecular and OpticalNEH 2.1: Resonant Inelastic X-ray ScatteringNEH 2.2: Soft X-ray ResearchNEH 1.2: Tender X-ray InstrumentXPP: X-ray Pump ProbeXCS: X-ray Correlation SpectroscopyMFX: Macromolecular Femtosecond CrystallographyCXI: Coherent X-ray ImagingMEC: Matter in Extreme Conditions
3 Soft X-ray
5 Hard X-ray
1 “tender” x-ray
SXUSXU
HXUHXU
FarHall
XCS MFX CXI MEC
NearHall
N1.1 N1.2 XPP
N2.1
N2.2
~ 50 m ~ 70 m
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Optics Configuration in Front End
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
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KB mirror systems for Soft and Tender X-ray
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
à 6 pairs of KB mirror systems
NEH 1.1• TMO• Bendable K-B Pair
─ 1 μm• Fixed Figure K-B Pair
─ 300nm• 250-1300 eV
NEH 1.2• Tender X-ray Instrument• SXR Bendable K-B Pair
─ 1 μm• HXR Bendable K-B Pair
─ 1 μm• 400-6000 eV
NEH 2.1• RIXS• Bendable K-B Pair
─ 2x10μm• 250-1350 eV
NEH 2.2• Spectroscopy• Bendable K-B Pair
─ 1x4 μm• 250-1350 eV
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Outline of the presentation
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Ø Introduction§ LCLS, LCLS-II project§ X-ray Transport and Experimental Systems (XTES)§ Beamline instruments
ØMechanical engineering challenges in XTESØ Attenuators, beam stoppers and beam collimatorsØ X-ray optics and KB mirror systems§ Optics cooling§ Flat mirror§ Bendable KB mirror systems
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Mechanical engineering challenges in XTES
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Ø Extremely high peak power, mJ energy per pulseà TW§ Single shot damage
Ø High rep-rate FELà High average power: 200 ~ 600 W§ Effective cooling necessary§ Multiple shots fatigue and damage issue
Ø Nearly monochromatic beam (especially with self-seeding)§ Offset mirror removes only 10% of beam power§ (~)All the optics, including final focusing mirrors to be actively cooled
Ø Fully coherent photon beam à Wavefront preservation
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Design consideration for heat load components
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Peak power versus average powerØ Peak powerà single shot damage threshold§ Instantaneous absorbed dose per atom
§ Datom << 1 eV/atomà Large ρatom d material: B4C, C (Diamond, graphite),…
Ø Average powerà stress, strain, thermal fatigue§ High thermal conductivity,
lower thermal expansion,high strength materials
Ø Multiple-shot fatigue and damage
Datom =aF sinqratomd
F: fluence (energy/cm2)α: absorption coefficientθ: incidence angleρatom: number of atoms per unit of volumed: photon beam extinction length
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Mechanical engineering challenges: optics requirements
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Ø Fully coherent photon beam à Wavefront preservation§ 2*FWHM beam size needed
§ Shape error requirement (SR ≥ 0.97)
§ Sub-nm shape requirement
¥ acceptance 2 FWHM accept. 1 FWHM accept.
Unfocussed beam Unfocussd beam Unfocussed beam 0
20
40
60
80
100
120
0.00.20.40.60.81.01.2
0 500 1000 1500
Div
erge
nce
[µra
d]
Bea
mFo
otpr
int[
m]
Photon Energy [eV]
FootprintDivergence
θ=14 mrad
SR=0.97
SR=0.80
Unfocussed beamFocused beam
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Outline of the presentation
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Ø Introduction§ LCLS, LCLS-II project§ X-ray Transport and Experimental Systems (XTES)§ Beamline instruments
Ø Mechanical engineering challenges in XTES
ØAttenuators, beam stoppers and beam collimatorsØ X-ray optics and KB mirror systems§ Optics cooling§ Flat mirror§ Bendable KB mirror systems
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Photon beam stoppers and collimators
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Ø Design principle§ 750-µm CVD Diamond absorbs most of photon beam power§ 2-µm Graphite coating to prevent diamond from graphitization at Carbon
k-edge§ 10-mm SiC + 10-mm Heavy metal absorb high energy photons§ Lateral cooled by contact (+ eutectic GaIn interface)
CVD Diamond: 750µmGraphite: 2 µm coating
SiC: 10mm
Heavy Met: 10mm
Heat sink
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Beam Collimators, Apertures/Slits
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Courtesy of S. Forcat Oller
HeavyMet (WHA)
SiC
graphite coatedCVD Diamond
Core assembly
CVD DiamondOptical grade polycrystalline CVD diamond50±0.1 OD x (8, 8.5, 9, 12, 18 ID) mm750µm thickness with 2 µm graphite coating
SiC discSiC Diamond composite, grade Thermadite 100-60
60 vol.% of 100um diamond
70±0.1 OD x (8, 8.5, 9, 12, 18 ID) mm
10mm thickness
HeavyMet discAlloy HD18DV (95% tungsten + 3.5% nickel + 1.5% iron)
ASTM-B-777-15 - Class 3, for vacuum application
Density: 18 g/cm3
70 OD x (8, 8.5, 9, 12, 18 ID) mm
10mm thickness
Copper holder
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Photon stoppers
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Courtesy of HZ Wang, YP Feng
Beam
83x83x101mm3, W
Burn through monitor
OFHC heat sink
SiC plate
CVD diamond plate
SiC plate
CVD diamond plate
Unfocused fullbeam
750 mm Diamondw/ 2 mm graphitecoating+ 10-mm SiC plate+ heavy metal
redundant stopperspair
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SXR Gas Attenuator
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Ø Similar concept to LCLS gas attenuator, but§ 15 m long, N2 à Ar, higher pressure (up to 10 Torr)§ Differential pumping w/ variable size apertures
Ø Design figures§ Windowless, gas flow (no cooling)§ High differential pumping stages (9~10 order of magnitude)
Ø Requirements§ SXR (200 ~ 1300 eV)
10-5 Attenuation§ HXR (1000 ~ 2500 eV)
10-3 Attenuation
15 m
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SXR Gas Attenuator: High rep-rate issues
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Ø Gas power absorption à temperature increase à densitydecrease à less power absorption
Gas attenuator test at ESRF, 2009
Primary Slits26m
Xenon Attenuator30.9 m
Be window (0.3mm) Be window (0.3mm)
Beam
Diamond window (0.3mm)31.7 m
Calorimeter31.5 m
Diamond window (0.3mm)30.5 m
BeamSpectrumMeasurement
32.5 m
air
Diamond window (0.3mm)
Source
U42 or W70
2-mm Alspectral ratio (400mBar Xe / noGas)
0
0.2
0.4
0.6
0.8
1
0 20 40 60 80 100
eph (keV)
spec
tralr
atio
calc_P_0.40Measurementcalc_P_0.26
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SXR Gas Attenuator: High rep-rate issues
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Ø High Repetition Rate DensityDepletion Experiments at SLAC
Courtesy: YP Feng,D. Schafer
0μs 1μs 2μs 3μs
4μs 5μs 10μs 20μs
50μs 100μs
20 Torr
Courtesy: Dr. Eric Galtier(SLAC-MEC)
800[nm]“Pump”
10 images averagedat each time delayand divided by theaveraged referenceimages
hot core
pressurewave
Optical Test in SLACResearch Laser Lab
Optical Test Images
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Outline of the presentation
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Ø Introduction§ LCLS, LCLS-II project§ X-ray Transport and Experimental Systems (XTES)§ Beamline instruments
Ø Mechanical engineering challenges in XTESØ Attenuators, beam stoppers and beam collimators
ØX-ray optics and KB mirror systems§Optics cooling§ Flat mirror§ Bendable KB mirror systems
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Thermal deformation of the optics
Optimizing X-ray mirror thermal performance using matched profile cooling,SRI 2015, NYC, L ZHANG et al.
Thermal Bending• Due to the temperature gradient -
variation in the thickness• Spherical shape deformation
• Dominant when Lfootprint ~ Loptics :white beam mirror
• Can be suppressed by optimizingmirror geometry and water cooling(see next slide)
Thermal Bump• Due to the temperature gradient -
variation along x-axisà Variable thickness along x-axis
bump shape deformation
• Dominant when Lfootprint < Loptics :monochromator crystal
• How to reduce this deformation ?Liquid Nitrogen cooling or else ?
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Thermal deformation of the mirror - bending
Ø Top-up-side cooling + notches§ Fully illuminated§ Top-up-side cooling§ Optimized cross sectionà Minimize temperature
gradient in the thicknessand bending deformation§ Possible for multiple undulator settings
(photon energy tuning)§ Possible for multiple coating stripes
§ 1st application at ESRF ID26 (2007)
§ Applied to all ESRF beamlines using white beam mirror, and/or manymultilayer optics since then
~ 0.01 µrad
Zhang L. et al., SRI2012, Phys. Conf. Ser. 425, 052029
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Variable footprintà mirror cooling challenging
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
LCLS-II power distribution on the offset mirror
θ=14 mrad
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Mirror cooling design – 3 schemes
Ø Top-up-side water cooling
Preliminary Design Review of the KB mirrors for LCLS-II SXRAugust 27, 2015, L. Zhang & D. Morton
back face view
2. Variable-length cooling
3. Electric heater + Single-length cooling
optical face view
1. Single-length cooling
• L. Zhang et al. J. Syn. Rad. (2015). 22,1170–1181• L. Zhang et al. , SRI 2015 Conference
RMSthermal : = f (Lheater, Paheater, x)
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Optimal heater + single-length cooling
Optimizing X-ray mirror thermal performance using matched profile cooling,SRI 2015, NYC, L ZHANG et al.
Ø At least, two parameters can beoptimized: heater length andpower (or power density)
Ø There is an optimal heater powerdensity for a given heater length
Ø Optimal heater parameters (lengthand power density) for a givenpower load distribution (or eph)
( )optcoolmiroptheater LLL -- -»21
Wheater = 5 mm
800eV, 2*FWHM=304 mmXFEL power: 20 W
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Mirror cooling design – performance
Ø LCLS-II SXR K-B mirrors§ For 20 W of XFEL beam power, full-length (top-up-side) cooling is
sufficient§ For 200 W of XFEL beam power, optimal, variable-length cooling is
needed
Preliminary Design Review of the KB mirrors for LCLS-II SXRAugust 27, 2015, L. Zhang & D. Morton
Resistive Element Adjustable Length
REAL Cooled Optics(DoE funded R&D project – WavefrontPreserving Mirrors,2017-2018 FY, SLAC, BNL, ANL, LBNL)
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LCLS-II FAC Review, July 19-21, 201630
Mirrors characteristics/requirements - Baseline
1.4 m 2 m 2.5 mz
Undulator flat mirror H-KB V-KB FP1 variable to FP2
90m (from undulator exit) 15 m
Flat mirrorØ 1 m long (950X25 mm2 useful)Ø Angle of incidence 12 mradØ Coating B4C and NiØ Shape errors
< 0.3 nm rms on 300 mm< 0.6 nm rms with beam< 1 nm rms on 950 mm< 2 nm rms with beam
KB mirrorsØ 1 m long (950X25 mm2 useful)Ø Angle of incidence 14 mradØ Coating B4C and NiØ Shape errors
< 0.3 nm rms on 300 mm< 0.6 nm rms with beam after bending< 1 nm rms on 950 mm< 2 nm rms with beam after bending
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Offset mirror (flat)
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Ø Sub-nm shape errorà Jtec (EEM-Elastic Emission Machining)Ø First 3 mirrors received in May 2016 at SLACØ Performance: < 0.2 nm rms in the central 300 mm, and < 0.6 overallà the best ever manufactured mirror in the world!
Measured shape errors at parallel linesat the vendor premise
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Offset mirror (flat)
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
5 cooling circuits, 3 lengths(1st step towards variable-length cooling)
mirrorsurface
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Outline of the presentation
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Ø Introduction§ LCLS, LCLS-II project§ X-ray Transport and Experimental Systems (XTES)§ Beamline instruments
Ø Mechanical engineering challenges in XTESØ Attenuators, beam stoppers and beam collimators
ØX-ray optics and KB mirror systems§ Optics cooling§ Flat mirror§ Bendable KB mirror systems
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34
KB mirror system, technical challenges
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Ø Kirkpatrick-Baez (K-B) mirror configuration
Ø Ellipsoidal shape
Ø Technical challenges§ Large Acceptance à Long mirror§ Variable Source & Focal Pointsà Bendable Mirror§ Sub Nanometer Shape Errorà Limited Suppliers§ High Demagnificationà Tight Bending (stress issues,…)§ Few tenth nrad residual bending errorà Variable Mirror Width§ High Thermal Loads & Variable Footprint à Innovated Cooling§ Minimize the coupling between the mirror Bending & Cooling
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35
Design Solution
Vertical Focusing Mirror
Horizontal Focusing Mirror
Ø LCLS-II K-B mirror system§ Dynamically bendable§ Water cooled
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• Invar 36 Strongback• Titanium Flexure Benderw/ Height Correction
• Titanium Flexure Benderw/ Twist Correction
36
Bender
• Flexure Lock Plates• Titanium Leaf SpringLever Arms
• Titanium Push PullFlexures
• UHV Linear Actuators• High StrengthAerospace Epoxy
• Variable Width Profile SiMirror
http://www.janssenprecisionengineering.com/precisionpoint/Hart-Smith, L.J. (1983), “Designing to Minimize Peel Stresses inAdhesive-Bonded Joints”
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• Cooling Pads
37
Cooling
• Invar Supports• Copper Cooling Rails• Clamps• Gallium Indium
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38
Technical challenges
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
§ Large Acceptance à Long mirror§ Variable Source & Focal Pointsà Bendable Mirror§ Sub Nanometer Shape Errorà Limited Suppliers§ High Demagnificationà Tight Bending (stress issues,…)
§ Sub-µrad residual bending errorà Variable Mirror Width§ High Thermal Loads & Variable Footprint à Innovated Cooling§ Minimize the coupling between the mirror Bending & Cooling
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39
Mirror profile optimization
Preliminary Design Review of the KB mirrors for LCLS-II SXRAugust 27, 2015, L. Zhang & D. Morton
Ø Width profile defined by Bending Equation (BE)
Ø Limitation of the analytical formula(Beam theory approximation)
)()(12)( 3 xREt
xMxw =
F1 = F2 = 60 N
F1 = 62.92 NF2 = 63.58 N
Residual Slope Error (RSE) :Δslope = slope – slopeellipse
ANSYS Release 16.0 16.0AUG 4 201508:31:00ELEMENTS/EXPANDEDPowerGraphicsEFACET=1
1
FE model with bending forces (VFM)
F
X Y
Z
LCLS-II KB mirror: VFM, Fin=60, Fout=60 N, Ndxc=8, i=5
R(x)
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40
Mirror profile optimization
Preliminary Design Review of the KB mirrors for LCLS-II SXRAugust 27, 2015, L. Zhang & D. Morton
ANSYS Release 16.0 16.0AUG 4 201508:31:00ELEMENTS/EXPANDEDPowerGraphicsEFACET=1
1
FE model with bending forces (VFM)
F
X Y
Z
LCLS-II KB mirror: VFM, Fin=60, Fout=60 N, Ndxc=8, i=5
Silicon crystal orientation(low stress & bending force)
• Mirror optical surface //Si (110) plan
• Tangential-axis // [001]
Optimized Mirror Profile (VFM, q=2m)
V201505
• L. Zhang, SMEXOS (2009), Grenoble, France• L. Zhang et al., AIP Conference Proceedings
1234, 801 (2010); doi: 10.1063/1.3463335
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41
Optimized Mirror Profile – bending performance
Preliminary Design Review of the KB mirrors for LCLS-II SXRAugust 27, 2015, L. Zhang & D. Morton
iter=1 iter=2 iter=3 iter=4 iter=5
RMSΔslope (reduction factor : ~ 104)§ 43.7 μrad (with the profile defined by BE)§ 0.005 μrad (with the optimized profile by FEA)
RMSΔslope-opt /slopePV-ellipse ~ 2 10-6
à Following effectsto be taken into account
§ Bender stiffness (not negligible)§ Anticlastic-bending effects§ Anisotropy of the Si crystal§ Geometrical non-linear effects in
the simulation
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42
Technical challenges
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
§ Large Acceptance à Long mirror§ Variable Source & Focal Pointsà Bendable Mirror§ Sub Nanometer Shape Errorà Limited Suppliers§ High Demagnificationà Tight Bending (stress issues,…)§ Sub-µrad residual bending errorà Variable Mirror Width§ High Thermal Loads & Variable Footprint à Innovated Cooling
§ Minimize the coupling between the mirror Bending & Cooling Minimization of mechanical constraint effects of Eutectic GaIn
as thermal interface
Bend cooling blocks (design optimization practice)
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43Minimization of mechanical constraint effects of Eutectic GaIn as thermal interfaceMEDSI 2016, Sept. 11-19, 2016, L. ZHANG
GaIn interfaces (pink lines) , gap = 50 μm
Mirror bendingà mirror motion (up-down)relative to fixed cooling blocks
MN
MX X Y
Z
What’s the mechanical constraint effectsduring the mirror bending?
Eutectic GaIn as thermal contact interface
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44
Eutectic Gallium-Indium (eGaIn)
Minimization of mechanical constraint effects of Eutectic GaIn as thermal interfaceMEDSI 2016, Sept. 11-19, 2016, L. ZHANG
Ø eGaIn: 75.5% Gallium (29.76ºC)24.5% Indium (156.6ºC)
Ø Thermal interface§ Thermal conductance > 105 W/m2.K, ~ 10 times better than Indium foil§ Interface or trough / bath for indirect cooling of the X-ray mirrors
Ø Mechanical properties§ Bulk viscosity ~ 2 mPa*s (2µwater)§ Modulus ??§ Thin skin (oxides of Ga)
Dickey et al., Adv.Funct.Mater.2008,18,1097–1104
Dickey, ACSAppl.Mater.Interfaces2014,6,18369−18379
Tmelting=15.7ºC
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45
GaIn test Setup
Minimization of mechanical constraint effects of Eutectic GaIn as thermal interfaceMEDSI 2016, Sept. 11-19, 2016, L. ZHANG
Ø Si-wafer (D=4”, t = 4 mm, both side polished)
Ø GaIn gap: (51, 102, 152, 203, 254 μm)
Ø Measurements§ Displacement of Si-wafer dwafer§ Forces of Si-pads on
Left side and Right side: F_L, F_R§ Relative displacement between wafer and pads: dpad = dwafer – (F – F0)/ kFG§ Force gauge stiffness: kFG = 10.57 N/mm
Displ. Sensor A
Displ. Sensor B
Silicon wafermoving part
Silicon padfixed on aforce sensor
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46
GaIn Test results – Data fitting, modulus
Minimization of mechanical constraint effects of Eutectic GaIn as thermal interfaceMEDSI 2016, Sept. 11-19, 2016, L. ZHANG
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47
GaIn test results – gap dependant; Modulus G1 and G2
Minimization of mechanical constraint effects of Eutectic GaIn as thermal interfaceMay 2nd, 2016
G2 = 9 Pa
Shear modulus G of GaIn interfacegap G2_av G2_min G1
μm Pa Pa Pa50 43.7 20.0 1421
100 16.2 8.6 534
150 10.3 3.4 232
200 8.2 4.7 285
250 8.3 4.8 94
G1
G2
# cycles(motionpatterns)
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48
Bending Operation Optimization with GaIn Interface
Minimization of mechanical constraint effects of Eutectic GaIn as thermal interfaceMEDSI 2016, Sept. 11-19, 2016, L. ZHANG
BE
q=4 m
q=2 m
~2 mN
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49
FEA results with cooling blocks and GaIn interface
Minimization of mechanical constraint effects of Eutectic GaIn as thermal interfaceMEDSI 2016, Sept. 11-19, 2016, L. ZHANG
ANSYS Release 16.0 16.0MAR 30 201617:20:31PLOT NO. 199NODAL SOLUTIONSTEP=1SUB =1TIME=1/EXPANDEDUZ (AVG)RSYS=0PowerGraphicsEFACET=1AVRES=MatDMX =.412588SMN =-.175605SMX =.025594
1
MN
MX
Vertical displacement of the mirror Uz (mm)
F
X Y
Z
-.175605-.15325-.130894-.108539-.086183-.063828-.041473-.019117.003238.025594
VFM,FP1, GaIn(200um, G=9 Pa), Fin=90.014,Fout=90.011N, Uz_BC=0um
G2=9 Pa
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50
FEA results with cooling blocks and GaIn interface
Minimization of mechanical constraint effects of Eutectic GaIn as thermal interfaceMEDSI 2016, Sept. 11-19, 2016, L. ZHANG
Residual Slope Error (RSE) :Δslope = slope – slopeellipse
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51
GaIn gaps
Minimization of mechanical constraint effects of Eutectic GaIn as thermal interfaceMEDSI 2016, Sept. 11-19, 2016, L. ZHANG
gGaIn = 500 μm
gGaIn = 50 μm
gGaIn = 200 μm
Before assemblingfor test at gGaIn=152 μm
After test atgGaIn= 152 μm
Wafer side
Wafer side
pad
pad
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52
Intensity distribution around focus (1300 eV)
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
SRW Sirepo(Oleg Tchoubar +Radiasoft)
Single lengthcooling(no correction)
Single lengthcooling(focus correctionby translation)
REAL cooling(focus correctionby translation)
10 mm in front at the focus 10 mm behind
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53
Intensity distribution around focus (500 eV)
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
SRW Sirepo(Oleg Tchoubar +Radiasoft)
Ø Intensity distribution at focus
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54
Collaboration with NSLS-II
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
Wavefront preserving mirrors(DoE funded R&D project, 2017-2018 FY, SLAC, BNL, ANL, LBNL)
NSLS-II:Mourad Idir: wavefront sensorOleg Tchoubar: wavefront propagation simulation…...
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55
Acknowledgement
LCLS-II project and beamline instruments: mechanical engineering challengesNSLS-II Engineering Seminar Series, Oct 18, 2016, L. Zhang
• E. Anderssen LBNL• R. Baker ESRF• J.C. Castagna SLAC/LCLS• M. Church SLAC/SSRL• R. Duarte LBNL• Y.P. Feng SLAC/LCLS-II• S. Forcat Oller SLAC/LCLS-II• D. Harrington SLAC/SSRL• T. Rabedeau SLAC/SSRL• A. Ringwall SLAC/SSRL• E. Ortiz SLAC/LCLS-II• B. Schlotter SLAC/LCLS-II• O. Tchoubar BNL/NSLS-II• H.Z. Wang SLAC/LCLS-II
Many SLAC colleagues
These works performed under DOE Contract DE-AC02-76SF00515.