MultiAnvil Techniques For Synchrotron Applications

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Multi-Anvil Techniques For Synchrotron
Applications

• Yanbin Wang
• GSECARS
• The University of Chicago

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Outline

• Beam Line Characteristics
• Limitations with Multi-anvil modules
• Applications
• Phase relations and EoS
• Melting curves
• Melt properties viscosity, density
• Deformation of crystals
• High P-T Crystallography

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Brilliance of Synchrotron Radiation
A one second APS undulator (1019) exposure 30
years using Cu Ka rotating anode (1011)
Focused beam
Non-focused
Discovery of x-rays
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Beam Characteristics
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Angle-dispersive vs. Energy-dispersive Diffraction
Braggs Law l 2d sinq
EDD (l continuous), fix 2q angle and observe
intensity vs. photon energies. E hw h
(2p/l) and Braggs law can be re-written as d
12.398/E sin(q)
ADD measure intensity as a function of 2q at a
given wavelength
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C
Multiple techniques for a wide range of earth
science problems
Phase equilibrium A, B, C Equation of State A,
B, C, E Ultrasonic EOS A, C, E Melting A, B,
C Viscosity of melts A, C High-P tomography
D Deformation E, D Melt structure D
D
E
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Energy-dispersive diffraction requirements

• Diffraction geometry is defined by incident and
  diffracted side slits
• Both are fixed relative to the incident beam
• Sample must be moved into the intersecting
  point of the incident and diffracted beams for
  diffraction
• Press has four degrees of freedom.

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Detectors and support frames
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X-ray access in multi-anvil press
GSECARS, WC, 30 GPa, 2500K 2q10
Spring-8, WC SD, 40 GPa, 2500K 2q 10
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Beam Access Limitations
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T-cup cell assembly
beam
TC
heater
Sample 1
Sample 2
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P-T Path for phase relation and EOS
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Melt Trade-off btwn Bragg coverage and
collimation
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Viscosity of Melts Under High P-T
Terminal velocity vt (2 Dr r2 g) / (9 h)
Dr rsphere - rmelt r sphere radius.
Diopside Reid et al., unpublished
Dacite Tinker et al., Am Min, in press
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Composite spheres
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Microtomography
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Segregation of Fe-S, Fe-H, Fe-Si, Fe-C melts in
mantle silicates

• Mixtures of silicate (olivine or enstatite) and
  Fe, plus light elements, as indicated.
• Heated to high temperature and quenched at
  various stages of melting process.
• Shown here are tomography images of the "final"
  products.
• Note different textures when different light
  elements are involved.

• Fe-H and Fe-S melts (left) segregate rapidly,
  forming spheres that fall to the bottom of the
  sample chamber, suggesting low melt viscosity and
  high dihedral angle.
• Fe-C and Fe-Si melts (right), on the other hand,
  are well mixed with the silicate matrix,
  suggesting high melt viscosity or low dihedral
  angle.
• Work is under way to develop a high-pressure
  tomography cell, so that the segregation process
  can be studied in-situ.

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Overall configuration
Thrust bearings
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Pressure generation Drickamer cell
SiC
cBN
Al
BE
WC
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3D reconstruction and determination of
inclusion volume
B
Use Blob3d to extract the sphere. Contrast
between area A and the sphere is poor. Requires
separate processes to remove B in area A.
B
Anvil
3 ton
6 ton
A
Segmented area
9 ton
12 ton
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P-V-T equation of state for liquids
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The Deformation DIA (Wang, Durham, Getting,
Weidner, RSI, 74, 3002, 03)www.gsecars.org/LVP/p
ublication/LVP_publication.html

• Up to 15 GPa and 1500C
• In situ measurement (e, P, T, s)
• Up to 2 mm sample length, 50 steady-state
  deformation
• ? Independent s1, s3 control and measurement
• ? Strain imaging (sub mm resolution in length
  measurement)

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Setup for D-DIA with Mono Diffraction
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Pressure and temperature gradients at 6 GPa
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Stress-Strain Curves w/ Controlled Strain Rates
Rheology of Solids
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Combined Angle- and Energy-dispersive Structural
Analysis and Refinement
(CAESAR)
EDS
APS test scan Undulator gap, average 19
mm Undulator taper 2 mm Sample corundum (SRM
674a) 2q range 3 - 12? (vertical) Beam size
0.1x0.1 mm SSD scanning step size 0.01? SSD data
collection time 40 s/step SSD energy
uncertainty 10-20 eV SSD energy resolution
160 eV at 22 keV 480 eV at 136 keV
ADS
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ADD
EDD
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High P-T Test in SPEED 1500, Spring-8
Intensity correction Ic C Io sin(2q)/(wi x
wd), LD Ic C Io/(wi x wd)/sin(2q)
¼ (L-D)2 tan(2q), LgtD
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Energy binning, SP8 data
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A simulated 0.1? step-size scan
40 channels binned, DE/E5
wRp 0.12
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Conclusions

• Multi-anvil press a versatile technique
• Many possibilities of combining additional probes
  with synchrotron
• Constantly expanding capabilities depending on
  user needs
• GSECARS facility open to all users
• Next general user proposal deadline March 11,
  2005
• Contact wang_at_cars.uchicago.edu