High-Pressure Micro X-Ray Diffraction Equipment

◆Equipment overview

This equipment is a multi-purpose X-ray diffractometer that can be equipped with various high-pressure, diamond anvil cells. It is prepared with an online double-sided laser heating system, which allows the use of an imaging plate and a flat panel detector as two-dimensional X-ray detectors.

◆Features of the Equipment

Diffractometer
This equipment is a X-ray diffractometer that can be equipped with various diamond anvil cell diffraction devices (Diamond Anvil Cell, DAC) such as symmetry-type devices, box-type devices, lever-type devices, etc. It consists of a high-load-bearing, precision XYZ stage and a high-accuracy single-axis rotation stage. High-pressure samples can be matched to the center of rotation of the diffractometer by a precision movement stage. The precision of the center of rotation (eccentricity) is less than a few microns. The diffractometer can be combined with an online double-sided laser heating optical system, and can also be equipped with a resistance heating vacuum chamber and a heavy freezer.
High-temperature, high-pressure X-ray diffractometer measurement are completed by an online double-sided laser heating optical system.

Detector
Imaging Plate X-Ray Detector:
This is a detector with a large area and wide dynamic range, with a wide measurable X-ray energy range. It is mainly used for precise crystal structure analysis which is acquired through observation of wide reciprocal lattice space and diffraction line strength data. The camera length between the sample and the detector during the measurement can be moved within the range 200 to 450mm, depending on the measurement angle range and angular resolution. When a camera length of 450mm is used, the angular resolution is 0.013 degrees. If the camera length of the detector is set to 200mm and offset horizontally, the observable diffraction angle can be extended to 45 degrees or more. The IP detector is called R-AXIS IV++, and is manufactured by Rigaku, and it has an area of 300×300 mm², a reading resolution of 0.10mm, and a dynamic range of 20bits.

Flat Panel X-Ray Detector (FPD):
This detector is a 2-dimensional detector with directly deposited CsI: Tl for high-energy X-rays. High-speed readouts of the 2-dimensional diffraction images is possible, and it is also used for time-resolution measurements and real-time monitoring. The camera length between the sample and the detector during the measurement has a movement range between 200 and 430mm. FPD is an XRD0822 CP23 manufactured by Perkin Elmer, with 1024×1024 pixels, a pixel pitch of 0.20mm, a dynamic range of 16bits and a maximum frame rate of 25fps.

Control Software
Control of the IP detector uses dedicated software which was developed by Rigaku. The FPD detector is operated by measurement software programmed by LabVIEW, which is manufactured by National Instruments. Various stages are operated by software programmed with VB or LabVIEW based on equipment control Tsuji Electronics steppe motor controller PM16C.

Available Electric Field: 14.4~61 keV
Energy Resolution: ΔE/E~10^-4
Beam Size: φ0.01~1.0 mm (FWHM)
Beam Intensity at Sample Position: : 1×10¹¹ photons/sec (30 keV, Beam Size φ0.01 mm), 5×10¹⁰ photons/sec (61 keV, Beam Size φ0.01 mm)

◆Equipment accessories

Online double-sided heating laser optical systems
・Water-cooled continuous wave 100W Fiber Laser（SPI，1070 nm）: 2 units
・Flat-top Beam Smoothing Optical Systems
・Sample Position Laser diameter: 10~40 Microns (variable)
・Temperature Range: 1500~6000 K

Online Raman Scattering Spectrometer
・Excitation Light Source: CW (continuous) oscillating DPSS laser 532 nm (50 mW), CW oscillating diode laser 632.8 nm (50 mW)
・Splitter: Teledyne Princeton Instruments SP2500i
・Grating: 1200 gr/mm, 1800 gr/mm，f = 500 mm
・Detector: Electric Cooling mechanism CCD (Teledyne Princeton Instruments PIXIS）
・Control and Measurement Software: Teledyne Princeton Instruments LightField
・Confocal Focus Raman Probe Unit (Object Lens: ×20，WD26.6 mm）

Cryogenic Refrigerator Systems
・4K GM Freezer
・Temperature Range (DAC Sample Position)：10~300 K
・Minimum Temperature Arrival Time: 120 Minutes
・The four-terminal method can be used with necessary electrical resistance measurements from the signal wire (lead wire)

◆Experiment / sample preparation

・Room temperature high-pressure experiments are based on the use of symmetric (outer diameter 48mm), and box type (50x50x55mm) diamond anvil cell devices (DAC). Please contact us in advance when bringing in other shaped DACs to conduct experiments.
・The double-sided laser heating optical system uses high-temperature, high-pressure X-ray diffraction in experiments with symmetric DACs (outer diameter 48mm, length 36mm)．
・The aperture opening angle of the diamond anvil should be selected in consideration of the X-ray wavelength and the measurement range of the diffraction angle, as well as the laser irradiation size.
・During high-temperature, high-pressure experiments, the sample encapsulation gasket should be prepared with Rhenium or Tungsten. Stainless steel with reduced toughness under high temperatures is not suitable.
・ Drill into gasket material (De-burring is necessary)
・ When filling the sample chamber with rubies（Al₂O₃: Cr³⁺）as pressure markers, set a grain of ruby at the anvil tip on the detector side in experiment hatch 2.
・ If you wish to use the diamond anvil cell high-pressure device which is installed in the beamline, please contact us in advance, as it is necessary to use the glovebox for experiments under quasi-hydrostatic pressure using a Helium pressure medium.

◆Experimental procedure / precautions

Basic Experimental Procedures
・Using standard substances, determine the incident X-ray wavelength and camera length (distance between the sample and the detector).
・After reviewing the X-ray diffraction (XRD) pattern from the departure substance, enclose the sample in the diamond anvil cell (DAC) (Optionally, for using Helium as the pressure medium for high-pressure gas filling, use the glovebox).
・Complete pressure measurements in the DAC sample chamber (Ruby fluorescence method, Diamond raman method or XRD)
・In the case of high-temperature, high-pressure experiments by laser heating, complete heating adjustments (laser irradiation alignment, observation of the samples in the DAC by laser optical systems)
・Move the X-ray irradiation position for the sample inside the DAC (Adjust each optical axis for the heating laser irradiation position and align the X-ray irradiation position of the sample inside the DAC)
・Measure and adjust the XRD sample intended temperature and pressure (laser power adjustment, temperature measurements)

Notes
・If you wish to use a laser heating optical system or a freezer system, please contact us in advance. It is based on the use of a Diacell®Bragg-LT type CuBe system as a high-pressure device that can be installed in the freezer. However, if the appearance size (including the fixed screw position) is the same as the DAC, it can be incorporated into the freezer.
・Diamond anvils used in the DAC may be destroyed when under high load during pressurization and laser heating.

◆Contact

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◆List of representative treatises

Equation of state of liquid iron under extreme conditions
Y. Kuwayama, G. Morard, Y. Nakajima, K. Hirose, A. Q. R. Baron, S. I. Kawaguchi, T. Tsuchiya, D. Ishikawa, N. Hirao, Y. Ohishi
Physical Review Letters, 124, (2020) 165701.
DOI: 10.1103/PhysRevLett.124.165701

Formation of H2-rich Iodine-Hydrogen Compounds at High Pressure
J. Binns, P. Dalladay-Simpson, M. Wang, G. J. Ackland, E. Gregoryanz, R. T. Howie
Physical Review B, 97, (2018) 024111.
DOI : 10.1103/PhysRevB.97.024111

Experimental Determination of the Electrical Resistivity of Iron at Earth’s Core Condition
K. Ohta, Y. Kuwayama, K. Hirose, K. Shimizu, Y. Ohishi
Nature, 534, (2016) 95-98.
DOI : 10.1038/nature17957

High-Pressure Generation using Double Stage Micro-Paired Diamond Anvils Shaped by Focused Ion Beam
T. Sakai, T. Yagi, H. Ohfuji, T. Irifune, Y. Ohishi, N. Hirao, Y. Suzuki, Y. Kuroda, T. Asakawa, T. Kanemura
Review of Scientific Instruments, 86, (2015) 033905.
DOI : 10.1063/1.4914844

Equation of state of bcc-Mo by static volume compression to 410 GPa
Y. Akahama, N. Hirao, Y. Ohishi, A. K. Singh
Journal of Applied Physics, 116 (2014) 223504.
DOI: 10.1063/1.4903940