LCLS-II project and beamline instruments: mechanical ... · 10/18/2016 · LCLS-II project and...
Transcript of LCLS-II project and beamline instruments: mechanical ... · 10/18/2016 · LCLS-II project and...
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
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 ?
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)
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
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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Design Solution
Vertical Focusing Mirror
Horizontal Focusing Mirror
Ø LCLS-II K-B mirror system§ Dynamically bendable§ Water cooled
• Invar 36 Strongback• Titanium Flexure Benderw/ Height Correction
• Titanium Flexure Benderw/ Twist Correction
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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”
• Cooling Pads
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Cooling
• Invar Supports• Copper Cooling Rails• Clamps• Gallium Indium
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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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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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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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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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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)
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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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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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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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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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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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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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
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
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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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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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
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…...
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.