1. Brillouin Scattering and Synchrotron X-Ray Measurements
at GSECARS, Advanced Photon Source:
Simultaneous Measurements of Sound Velocities and Density
A COMPRES Infrastructure Development Project
June 2005 Annual Meeting Status
Jay D Bass1
Stanislav V. Sinogeikin1
Vitali B. Prakapenka2
Dmitry L Lakshtanov1
Carmen Sanchez-Valle
Guoyin Shen2
Mark Rivers2
1: Geology Dept, University of Illinois, Urbana-Champaign, Urbana IL 61801;
2: GSECARS, University of Chicago, Chicago IL

2. Goals and motivations for building a Brillouin system at BMD-13
Simultaneous measurements of:
Density by x-ray diffraction
Sound velocities by Brillouin scattering
Determination of an absolute pressure scales.
The equation of state and velocities as a function of pressure could be determined without resort to a secondary pressure standard.
Velocity-density measurements under a wide range of P-T conditions.
High-T-P EOS parameters of materials (single crystal elastic constants, velocities, adiabatic and isothermal bulk moduli, shear modulus, and their P-T derivatives; thermal expansion and Gruneisen parameter as a function of P and T)
A central Brillouin facility, open to the entire community and not widely available elsewhere (except in a few specialized labs).

3. Interpretation of global seismic information:
Japan
Central America
Izu Bonin
Indonesia
Earth’s Surface
Fiji-Tonga
CMB ~2890 km depth
(Kárason and Van der Hilst, AGU Monograph, 2000)

4. Brillouin spectroscopy
frequency
LASER
l = nm
Analyzer
Fabry-Perot
Interferometer
elastic
several
frequencies
Brillouin
shifted,
VP and VS
DAC
nB,i0
2sin(*/2)
Vi =
obtain sound velocities (Vi = VP or VS)

5. Key design considerations
User-friendly: possible to operate without being an expert.
Quick setup and break-down of Brillouin experiments
Fast and reliable alignment procedure, requiring minimum setup time.
Complete remote control (of optics and electronics, data collection, outside the hutch
Compatible with both powder and single crystal diffraction techniques
Different scattering geometries : 50, 80, 180 degrees.
Compact ( limited space in beamline station)
Does not interfere with the other experimental techniques on the beamline
Satisfy all laser safety requirements for Class IV laser

6. Timeline
Ordering equipment (e.g. Fabry-Perrot interferometer).
Detailed design of the Brillouin system.
Building up prototype at UIUC
Testing , making blueprints, machining parts that could not be purchased.
September Installing a second level table at BMD-13. Installing Fabry- Perot interferometer in BMD-13.
October Installing most optical components at BMD-13.
January Installing laser and permanent translation stages. Collecting the first Brillouin spectrum of standard MgO single crystal on Jan 16, 2005.
February Commissioning. First measurements in DAC: single crystal-NaCl to 30 GPa, single crystal MgO to 25 GPa; polycrystalline B2-NaCl to 53 GPa.
Summer and fall Installation of additional components. Simultaneous high-T high-P measurements. Preparation for general users.
2006. Open for general users.

7. Building The Prototype System at U Illinois

8. Building prototype system in Urbana

9. BMD-13 hutch before installation of the Brillouin system

10. Schematic diagram and photographs of the Brillouin system installed at sector 13-BMD at APS

11. Complete Brillouin system combined with X-ray diffraction hardware

12. Schematic diagram of the Brillouin system installed at sector 13-BMd at APS (Upper level)
Permanent optical elements: M - mirror; L - lens; BS - beam splitter; PR - dispersion prism; R - retroreflector; SF - spatial filter; PMT - photo-multiplier tube.
Laser beam / image conditioning elements (controllable from outside the hatch, blue boxes): SSh - safety laser shutter; PRot - polarization rotator; LDp - laser beam depolarizer; ICP - intensity control polarized for stalilization beam; IBS – imaging beam splitter; CF - color filter; NDF - neutral density filter.
Observation / feedback elements (red boxes): PD - photodiode; VC - video camera; MVC - microscope with video camera.
Beam / image alignment elements (yellow boxes): ID - iris diaphragm; ABBS - alignment beam beamsplitter; RBS - retroreflecting beamsplitter

14. Schematic diagram of the Brillouin system installed at sector 13-BMd at APS (Lower level)
Motorized translation components (controllable from outside the hatch, blue boxes): HMTS - horizontal motorized translation stage; VMTS - vertical motorized translation stage; MLFA - motorized laser focusing assembly; MSCA - motorized signal collecting assembly; SPOA - sample positioning and orientation assembly; SL-LB - sample light / light block.
Observation / feedback elements (red boxes): VC - video camera; BT - beam target.
X-ray components: MAR - MAR Imaging plate; XBS - X-ray beam stop; CS - cleanup slit.

16. X-ray and Brillouin control area for BMD-13

17. Computer interface for controlling X-ray and Brillouin optics and electronics

18. Schematic view of simultaneous Brillouin scattering and X-ray diffraction in DAC

19. Simultaneous X-ray and Brillouin experiments performed in BMD-13 in February 2005
NaCl in B1 phase to 30 GPa.
MgO to 25 GPa.
Aggregate acoustic velocities, elastic moduli and equation of state of polycrystalline NaCl in B2 phase to 53 GPa.
In all absolute pressure scale experiments gold + ruby (+ platinum + powdered NaCl) were added to experimental charges to cross calibrate these pressure standards against absolute equations of state of NaCl and MgO

20. Single crystal NaCl (B1) at ~30 GPa (left) and polycrystalline NaCl (B2) at ~53 GPa (right) in DAC in Ne pressure medium
NaCl
single
Ruby
100 μm
NaCl
poly
Au+Pt+NaCl
Ruby
100 μm
Au+Pt+NaCl

21. MgO in MEW pressure medium
MgO in MEW pressure medium. Typical DAC loading for absolute pressure scale measurements.
100 μm
MgO single X-tal
Au+Pt
Ruby

22. Single crystal X-ray diffraction and calibration Brillouin spectrum of MgO at ambient pressure

23. X-ray image and Brillouin spectrum of polycrystalline NaCl in B2 structure collected simultaneously at 35 GPa
NaCl Vp
NaCl Vs
Diamond Vs
NaCl Vp
Diamond Vs
NaCl Vs

24. X-ray image and Brillouin spectrum of single-crystal NaCl (B1) in Ne at 26 GPa
NaCl Vs
NaCl Vp
Diamond Vs
Ne Vp
Ne BS

25. Brillouin spectrum of single crystal MgO in [100] direction in a Diamond anvil cell at 4 GPa. Collection time is 3.3 min.
MgOVp
MgO Vs
MEW mix

26. COMPRES Jennifer Jackson Dave Mao J Shu
Acknowledgments
COMPRES
Jennifer Jackson
Dave Mao
J Shu