What are the key ingredients

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What are the key ingredients for a successful
laser heating experiment at the
synchrotron? Guoyin Shen CARS, University of
Chicago
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Some types of laser heating experiments
Overcome kinetic barrier Stress release In
situ phase identification at high P-T Phase
relations (melting) P-V-T equations of state
Phonons Electrons Magnetism
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Laser
X-ray
DAC
Sample
On-line detection
Off-line detection
Data evaluation
Science
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Diamond Anvil Cell - Allow double sided
heating - Have large access opening - Gasket
(thickness, energy) - Cooling (stability)
2q
X-ray transparent seat
Gasket
Diamond anvil
WC seat
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Laser heating system Type (YLF, CO2) Power
distribution (modes) Heating spot size Stability
(short and long term) Pointing stability (laser,
optics) Feed back system Temperature measurement
system User friendly
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X-ray beam Energy Size Cleanliness Visibility
lt10 mm beam
Detection
X-ray (5-7 mm)
Sample (gt20 mm)
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Alignment
Five path alignment (221) With coaxial optics,
three path alignment (111) X-ray position
(visual image, small marker) No pre-alignment,
every cell is unique Alignment stability (lt 2 mm)
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Sample environment Absorption considerations Sel
f absorption (metal, semi-transparent)
Mixture Double hot plates Insulation
considerations (medium) Materials (Ar, NaCl,
Al2O3, MgO, KCl) Thickness Diffraction
pattern, absorption, ... Sample Grain size,
thickness, shape (disc) Others Pressure
determination X-ray alignment Loading
environment
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Detection - Atomic structure diffraction,
EXAFS, - Phonons nuclear inelastic scattering,
- Electronic structure x-ray Raman, emission,
absorption - Magnetism Mössbauer, emission -
Chemical composition emission, absorption,
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Data evaluation Large amount of data notes
(data catcher), software Unexpected
features conditions, chemistry,
reproducibility Dynamic experiments on-line
analysis