Hironari Yamada

High aspect ratio micromachining Teflon by direct exposure to synchrotron radiation

Micromachining Teflon was achieved by direct exposure to synchrotron radiation and the microstructures made had the smallest surface detail down to 20 μm with structural height of more than 200 μm, that is, aspect ratio on the order of 10. The quality of micromachining Teflon by this process was found to be critically dependent on photon flux of the synchrotron radiation. Analysis of the mass distribution of gaseous species formed upon this process suggested that photochemical processes rather than pyrolytic processes may still dominate.

Driving force behind adsorption-induced protein unfolding: a time-resolved X-ray reflectivity study on lysozyme adsorbed at an air/water interface.

Time-resolved X-ray reflectivity measurements for lysozyme (LSZ) adsorbed at an air/water interface were performed to study the mechanism of adsorption-induced protein unfolding. The time dependence of the density profile at the air/water interface revealed that the molecular conformation changed significantly during adsorption. Taking into account previous work using Fourier transform infrared (FTIR) spectroscopy, we propose that the LSZ molecules initially adsorbed on the air/water interface have a flat unfolded structure, forming antiparallel beta-sheets as a result of hydrophobic interactions with the gas phase. In contrast, as adsorption continues, a second layer forms in which the molecules have a very loose structure having random coils as a result of hydrophilic interactions with the hydrophilic groups that protrude from the first layer.

Novel X-ray source based on a tabletop synchrotron and its unique features

Novel X-ray source is based on a smallest synchrotron named MIRRORCLE using a collision of electron beam and a tiny target. It is demonstrated that the brightness is comparable to SR, source size can be a nano-scale, the spectrum is very flat and dominated by hard components, and it is highly coherent.

Critical assessment of interacting boson model wave functions from measured gyromagnetic ratios of lowest eigenstates in even Os isotopes

Abstract The gyromagnetic ratios of the low-lying levels in the even 188−192 Os isotopes were measured. Of particular import, the ratios g (2 + 2 )/ g (2 + 1 ) were found to be 1.45 ± 0.18, 0.99 ± 0.14, and 0.72 ± 0.06 in 188 Os, 190 Os, and 192 Os, respectively. Although the E2 observables in these nuclides are accommodated quite well in interacting boson model descriptions (IBM-1 and IBM-2), both formulations fail to concurrently account for either the intra-nucleus or mass-dependent g -factor variations of the lowest eigenstates in these Os isotopes.

Commissioning of aurora: The smallest synchrotron light source

The first synchrotron light from the smallest storage ring Aurora was observed on November 2, 1989. We have established a half‐integer‐resonance injection method. The electron energy is successfully boosted up to 650 MeV without exciting the prepared resonance jumper. The stored current is presently limited by performance of the injector microtron which produces 10 μA on average, but we could accumulate 45 mA because of very large acceptance of the ring. The measured lifetime is 20 h when the vacuum pressure is better than 1×10−9 Torr. The observed beam size is 1.2(0.14) mm in radial (vertical) direction. Remodeling of the injector is in progress.

Photon Storage Ring

In a photon storage ring for storing SR light to generate the same through an outlet port, a reflection mirror is disposed to surround a circular orbit along which bundles of charged particles revolve at a speed close to the velocity of light, generating SR light at a direction tangential to the circular orbit. The reflection mirror has curvature such that the SR light generated in the tangential direction is reflected on the reflection mirror and sent as reflection SR light which is tangential to the orbit. The SR light and the reflection SR light interfere with each other and are guided towards the outlet port.

Refraction contrast 11×-magnified X-ray imaging of large objects by MIRRORCLE-type table-top synchrotron

The high-quality aspects of magnified X-ray images recorded using MIRRORCLE-6X are reported. MIRRORCLE-6X is inherently suitable for hard X-ray imaging owing to its magnified projection X-ray imaging, micrometre-size X-ray source point, wide radiation emission angle, X-ray spectrum ranging from 10 keV to 6 MeV, natural refraction contrast imaging and high flux output. Images produced with 11x geometrical magnification display a sharply enhanced edge effect when generated using a 25 microm rod electron target. Image contrast is enhanced 2x owing to refraction when compared with absorption contrast images. An imitation tumour implanted in a human chest phantom was made clearly visible by using edge enhancement on images. Soft tissue becomes highly visible as a natural consequence of refraction contrast when using hard X-rays for imaging. The authors believe that novel imaging provided by MIRRORCLE makes it a superior instrument for medical diagnosis.

Intermolecular vibrational study in liquid water and ice by using far infrared spectroscopy with synchrotron radiation of MIRRORCLE 20.

Far infrared absorption measurements for distilled water and ice Ih were performed in the frequency range from 20 cm(-1) to 1000 cm(-1) with Fourier Transform Infrared Spectrometer (FTIR) utilizing SR of a portable synchrotron. Four vibrational bands were separated from measured spectra in liquid water. We found that a peak frequency of 40±1 cm(-1) did not depend on the temperature in a range between 10.0°C and 70.0°C; however, any low energy excitation modes were not observed in the ice spectrum. It is concluded that this band is caused by collective vibrations specific to the dynamical structure in liquid water.

The Smallest Electron Storage Ring for High-Intensity Far-Infrared and Hard X-ray Productions†

The status of the worlds smallest electron storage ring is reported. This ring is designed to provide coherent far-infrared (FIR) and incoherent hard X-ray emissions from a single 50 MeV storage ring. The FIR emission is forced by a surrounding mirror around the electron orbit. The FIR emission mechanism is rather similar to that of the free-electron laser. The expected FIR output is of the order of 100 W. Bremsstrahlung is used instead of synchrotron radiation to generate hard X-rays. Since electrons recirculate and gain energy from the accelerating cavity, the expected hard X-ray brightness exceeds that of a rotating-anode source by about 1000 times or more.

Novel free electron laser named photon storage ring

Abstract Observed features of the smallest synchrotron radiation (SR) source AURORA are presented. A novel free electron laser named photon storage ring (PhSR) which is based on this SR source is proposed, and the lasing mechanism is described. In this scheme the SR is confined within a coaxial mirror surrounding the electron orbit. The simulation indicates 10 kW of continuous output power for sub-mm wavelength with the present scheme of AURORA.