Alignment and use of microbeam with full-field x-ray microscopes.

Demonstration tests of the alignment of Fresnel zone plate focusing optics using a full-field x-ray microscope and microbeam x-ray diffraction measurements combined with the full-field x-ray microscope were performed. It was confirmed that the full-field x-ray microscope enables direct two-dimensional observation of a microbeam with sub-micrometer spatial resolution. This allowed visualization of the misalignment of the focusing optics, resulting in accurate alignment of the optics within a short time.

X-ray zooming optics for analyzer-based multi-contrast computed tomography.

An X-ray analyzer-based optics with a zoom function is proposed for observing various samples with apparent-absorption contrast, phase contrast and scattering contrast. The proposed X-ray optics consists of a collimator crystal and an analyzer crystal arranged in a nondispersive (+, -) geometry with a sample placed between them. For the implementation of the zoom function, an asymmetrically cut crystal in the rotated-inclined geometry was used for the analyzer.

X-ray zooming microscopy with two Fresnel zone plates.

We propose a variable-magnification full-field x-ray microscope using two Fresnel zone plates (FZPs). By moving the positions of the two FZPs, the magnification can be continuously changed even if the sample and camera positions are fixed. It was demonstrated that the magnification can be changed in the range of 25-150× using a hard x-ray beam at 14.

Conceptual design of the Hybrid Ring with superconducting linac.

The Hybrid Ring with a superconducting-linac injector as a highly flexible synchrotron radiation source to enable new experimental techniques and enhance many existing ones is proposed. It is designed to be operated with the coexistence of the storage (SR) bunches characterized by the performance of the storage ring, and the single-pass (SP) bunches characterized by the performance of the superconducting linac. Unique experiments can be performed by simultaneous use of the SR and SP beams, in addition to research with various experimental techniques utilizing the versatile SR beam and research in the field of ultrafast dynamics utilizing the ultrashort pulse of the SP beam.

Effect of sulfur on sound velocity of liquid iron under Martian core conditions.

Sulfur has been considered to be a predominant light element in the Martian core, and thus the sound velocity of Fe-S alloys at relevant high pressure and temperature is of great importance to interpret its seismological data. Here we measured the compressional sound velocity (V) of liquid Fe, FeS and FeS using ultrasonic pulse-echo overlap method combined with a Kawai-type multi-anvil apparatus up to 20 GPa, likely corresponding to the condition at the uppermost core of Mars. The results demonstrate that the V of liquid iron is least sensitive to its sulfur concentration in the Mars' whole core pressure range.

Development of shock-dynamics study with synchrotron-based time-resolved X-ray diffraction using an Nd:glass laser system.

The combination of high-power laser and synchrotron X-ray pulses allows us to observe material responses under shock compression and release states at the crystal structure on a nanosecond time scale. A higher-power Nd:glass laser system for laser shock experiments was installed as a shock driving source at the NW14A beamline of PF-AR, KEK, Japan. It had a maximum pulse energy of 16 J, a pulse duration of 12 ns and a flat-top intensity profile on the target position.

Long Periodic Structure of a Room-Temperature Ionic Liquid by High-Pressure Small-Angle X-Ray Scattering and Wide-Angle X-Ray Scattering: 1-Decyl-3-Methylimidazolium Chloride.

The Bragg reflections of 1-decyl-3-methylimidazolium chloride ([C mim][Cl]), a room-temperature ionic liquid, are observed in a lowly scattered wavevector (q) region using high-pressure (HP) small-angle X-ray scattering methods. The HP crystal of [C mim][Cl] was characterized by an extremely long periodic structure. The peak position at the lowest q (1.

High-pressure glass formation of a series of 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide homologues.

We investigated the stability of the liquid phase of a series of 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Cmim][TFSI]) homologues with different alkyl chain lengths for 3 ≤ n ≤ 10 at room temperature. We found that all [Cmim][TFSI] samples (n = 3-10) formed a glassy state when pressure was applied. Intriguingly, the glass transition pressure (p) slightly increases up to n = 5, reaches a plateau at n ≧ 8, and increases again at n = 10.

Stability of the Liquid State of Imidazolium-Based Ionic Liquids under High Pressure at Room Temperature.

To understand the stability of the liquid phase of ionic liquids under high pressure, we investigated the phase behavior of a series of 1-alkyl-3-methylimidazolium tetrafluoroborate ([Cnmim][BF4]) homologues with different alkyl chain lengths for 2 ≤ n ≤ 8 up to ∼7 GPa at room temperature. The ionic liquids exhibited complicated phase behavior, which was likely due to the conformational flexibility in the alkyl chain. The present results reveal that [Cnmim][BF4] falls into superpressed state around 2-3 GPa range upon compression with an implication of multiple phase or structural transitions to ∼7 GPa.

Muonium in stishovite: implications for the possible existence of neutral atomic hydrogen in the earth's deep mantle.

Hydrogen in the Earth's deep interior has been thought to exist as a hydroxyl group in high-pressure minerals. We present Muon Spin Rotation experiments on SiO2 stishovite, which is an archetypal high-pressure mineral. Positive muon (which can be considered as a light isotope of proton) implanted in stishovite was found to capture electron to form muonium (corresponding to neutral hydrogen).

Pressure-induced structural change of intermediate-range order in poly(4-methyl-1-pentene) melt.

High-pressure in situ x-ray diffraction and specific-volume measurements on isotactic poly(4-methyl-1-pentene) melt have uncovered abrupt changes in the pressure dependence of microscopic structure as well as that of macroscopic density. The first sharp diffraction peak of the polymer melt, which is related to the intermediate-range order and is explained as resulting from the correlations between main chains, is suppressed at pressures less than 1 kbar. These changes in intermediate-range order show similarities to those seen in liquid-liquid or amorphous-amorphous transitions in simpler small molecule based systems, suggesting that this kind of phenomenon may occur in a wide range of materials.

Helium penetrates into silica glass and reduces its compressibility.

SiO(2) glass has a network structure with a significant amount of interstitial voids. Gas solubilities in silicates are expected to become small under high pressure due to compaction of voids. Here we show anomalous behaviour of SiO(2) glass in helium.

High-pressure in situ structure measurement of low-Z noncrystalline materials with a diamond-anvil cell by an x-ray diffraction method.

We have developed techniques for high-pressure in situ structure measurement of low-Z noncrystalline materials with a diamond-anvil cell (DAC) by an x-ray diffraction method. Since the interaction between low-Z materials and x rays is small and the sample thickness in a DAC is also small, the incoherent scattering from the anvils overwhelms the coherent scattering from the sample at a high-Q range. By using a cubic boron nitride gasket to increase the sample thickness and the energy-dispersive x-ray diffraction method with a slit system to narrow the region from which detected x rays are scattered, we can reduce unfavorable effects of the incoherent scattering from the anvils and correct them accurately.

Sixfold-coordinated amorphous polymorph of SiO2 under high pressure.

We have developed synchrotron x-ray absorption and diffraction techniques for measuring the density and structure of noncrystalline materials at high pressures and have applied them to studying the behavior of SiO2 glass. The density, coordination number, and Si-O bond length at a pressure of 50 GPa were measured to be 4.63 g/cm;{3}, 6.

High-pressure in situ density measurement of low-Z noncrystalline materials with a diamond-anvil cell by an x-ray absorption method.

We have developed techniques for high-pressure in situ density measurement of low-Z noncrystalline materials with a diamond-anvil cell (DAC) by an x-ray absorption method. In DAC experiments, accurate determination of the sample thickness is difficult. Moreover, since the sample in a DAC is thin and the interaction between low-Z materials and x rays is small, not the sample but the anvils absorb most of x rays.

A cubic boron nitride gasket for diamond-anvil experiments.

To maximize the thickness of the sample chamber in high-pressure experiments, we have conducted tests and have developed techniques relevant to the cubic boron nitride (c-BN) gasket for diamond-anvil cells. The c-BN gasket provides a sample chamber several times thicker than conventional metal gaskets. We have developed methods to prepare the gasket and to fill the chamber with the sample.

Pressure-induced structural change of liquid silicon.

High-pressure and high-temperature x-ray diffraction measurements indicate that liquid silicon contracts with increasing pressure without significant changes in the local structure up to 8 GPa and then transforms to a denser structure between 8 and 14 GPa. In spite of volume contraction, the nearest-neighbor interatomic distance expands by about 1.6% within this pressure interval, accompanied by an anomalous increase in the coordination number.