Search

Spin polarized 3He gas is currently widely used in various scientific fields and in medical diagnosis applications. The spin polarization of 3He nuclei can be achieved by spin-exchange optical pumping (SEOP). In SEOP, the 3He gas is enclosed in a glass cell together with alkali metals and is then heated to maintain the alkali metal vapor pressures at the appropriate levels. However, polarized 3He gas is highly sensitive to any inhomogeneity in its magnetic field, and any small field gradients caused by the heaters may cause degradation of the 3He polarization. To overcome this conflict between the heating process and the magnetic field, we have developed electrical heaters that essentially cause no magnetic fields. These heaters are thin and are flexible enough to be bent to within a radius of a few centimeters. These carefully designed heater elements and a double layer structure effectively eliminate magnetic field generation. The heaters were originally developed for SEOP applications, but can also be applied to other processes that need to avoid unwanted magnetic fields. [ABSTRACT FROM AUTHOR]

We developed a new method for the measurement of the dynamic birefringence induced by the alternating shear deformation in fluid samples. A quadrupole piezoactuator generates the pure shear deformation in the frequency range from 1 Hz to 5 kHz and causes the molecular orientation, or the anisotropic conformation of polymers and molecular associations, which is observed by the optical ellipsometry technique. The spectrum of the shear-induced birefringence observed for the isotropic phase of the liquid crystal p-n-hexyl p′-cyanobiphenyl (6CB) shows linear dependence on the frequency up to 5 kHz, corroborating the effective band of the experimental system. The sensitivity of the system was demonstrated by the quantitative measurement of the birefringence for the isotropic phase of p-n-pentyl p′-cyanobiphenyl (5CB). The system was also applied to the aqueous solution of the worm such as micelles and the result shows the relaxation of shear induced birefringence at around 10 Hz, which agrees well with the previous reports. [ABSTRACT FROM AUTHOR]

A 2.2-m Rowland-circle grazing-incidence monochromator with a fixed entrance slit and a fixed grating, has been instal1ed on the beamline BL8B1 at UVSOR, in which the axis of the monochromatized beam is unchanged for the wavelength scanning. Two gratings are interchangeable in vacuum. The designed useful region is 20-200 Å with a 2400/mm grating, but the actual useful region was 50-200 Å. At 100 Å, 10[sup 10]/s output photons were obtained with a resolution of 10[sup -3]. The horizontal width of the beam at the sample position was about 5 mm, while the vertical width was between 0.5 and 3 mm. [ABSTRACT FROM AUTHOR]

A grazing incidence constant deviation monochromator with a spherical concave grating was fabricated for use with undulator radiation. It has a simple scanning mechanism with fixed entrance and exit slits, as well as fixed directions of incident and exit beams. It has been installed into an undulator beamline at IMS. Synchrotron radiation from a bending section also can be introduced into the monochromator by using premirrors. The energy resolution of the monochromator is better than 70 meV at the photon energy of 94 eV with 10-μm slits, when the bending magnet synchrotron radiation is used. The spot size of the zeroth-order light is 1.5 ( v ) × 2.0 (h) mm² at the distance of 1.85 m behind a postmirror. The photon flux of the undulator radiation behind the exit slit is approximately 1 × 10[sup 12] photons/s at the peak, when both the entrance and exit slits are 100 μm (δE = 0.08 eV) and the stored current is 50 mA. [ABSTRACT FROM AUTHOR]

A new plane-grafting monochromator and calibration chamber were constructed for the radiometric calibration of plasma diagnostic devices. The monochromator is designed to cover a wavelength range of 1.8-238 nm with moderate resolving power of 500 ± 200 λ/δλ. To check the performance of the monochromator, spectral distribution and resolution were measured by experiments on photoemission from solids and photoionization of rare gases. The characterization of multilayer reflectors by the use of this beamline is demonstrated. [ABSTRACT FROM AUTHOR]

In this study, we developed a novel type of rheological measurement system. Here, a spherical probe is driven to rotate periodically by applying torques using quadruple electromagnets in a noncontact manner. Moreover, this system is an enhancement of our electromagnetically spinning (EMS) viscometer, which is widely used for measuring rheological flow curves in various industrial fields. The quadruple EMS method provides the frequency spectrum of viscoelasticity, in addition to shear viscosity, in a steady flow by switching the operation modes of the driving torque. We show the results obtained for Newtonian fluids and viscoelastic materials and demonstrate the validity of the system.

Spin polarized 3 He gas is currently widely used in various scientific fields and in medical diagnosis applications. The spin polarization of 3 He nuclei can be achieved by spin-exchange optical pumping (SEOP). In SEOP, the 3 He gas is enclosed in a glass cell together with alkali metals and is then heated to maintain the alkali metal vapor pressures at the appropriate levels. However, polarized 3 He gas is highly sensitive to any inhomogeneity in its magnetic field, and any small field gradients caused by the heaters may cause degradation of the 3 He polarization. To overcome this conflict between the heating process and the magnetic field, we have developed electrical heaters that essentially cause no magnetic fields. These heaters are thin and are flexible enough to be bent to within a radius of a few centimeters. These carefully designed heater elements and a double layer structure effectively eliminate magnetic field generation. The heaters were originally developed for SEOP applications, but can also be applied to other processes that need to avoid unwanted magnetic fields.

A phenomenon was discovered wherein light scattering strength from cracks increases when tensile stress is applied to micro-cracks produced in the interlayer dielectric film by chemical mechanical polishing treatment. It is likely that the change in light scattering intensity occurs because a region of high stress concentration (region with high variation in index of refraction) is produced near the crack tip due to stress, thus forming a type of scatterer. With this method, it is possible to detect only scatterers which respond to stress, and thus, it is possible to classify and separately detect cracks and particles., (© 2011 American Institute of Physics)

We briefly report on the performance and stability of periodic multilayer mirrors containing Y(2)O(3) and Al layers designed for normal incidence reflection at the He-II emission line (30.4 nm). We found that Y(2)O(3)∕Al multilayer coatings had higher reflectivity (24.9%) at 30.4 nm and significantly lower reflectivity (1.3%) at 58.4 nm than the conventional coatings such as Mo∕Si. Furthermore, we investigated the temporal stability of the Y(2)O(3)∕Al multilayer coatings. Our sample was kept under vacuum, dry N(2) purge, and normal atmosphere for over three months, and there were no measurable changes in the reflectivity. These results suggest that we can use Y(2)O(3)∕Al multilayer coatings as standard mirrors for the He-II radiation.

The characteristics of an APLF80+3Ce scintillator are presented. Its sufficiently fast decay profile, low afterglow, and an improved light output compared to the recently developed APLF80+3Pr, were experimentally demonstrated. This scintillator material holds promise for applications in neutron imaging diagnostics at the energy regions of 0.27 MeV of DD fusion down-scattered neutron peak at the world's largest inertial confinement fusion facilities such as the National Ignition Facility and the Laser Mégajoule.

For pump and probe experiments in x-ray free-electron laser (XFEL) facilities, accurate timing synchronization between short-wavelength femtosecond pulses from XFELs and short optical pulses from other light sources is required. For this purpose, the response time of a hydrothermal-method-grown ZnO is improved by over one order of magnitude via intentional iron ion doping. The fluorescence rise- and decay-time constants are measured to be less than 10 and 100 ps, respectively. Owing to its intense fluorescence even for single pulse XFEL excitation, the timing jitter of the soft x-ray pulse and timing electronics are evaluated to be less than 70 ps.

A ripplon is a thermally excited capillary wave propagating on liquid surface. Propagation of the ripplon reflects surface mechanical properties such as surface tension and viscoelasticity of the liquid. An optical beating ripplon spectroscopy technique developed by us was applied mainly to the observation of various surface phenomena on a lowly viscous liquid surface in the frequency range from 1 kHz to several 10 MHz. In this study, we carried out a light scattering observation of the highly damped ripplon on the surface of the viscous liquid. The spectral peak width of the damped ripplon was smaller for the higher viscosity and the optical beating technique could resolve such a structure. A strict description of the dynamic structure factor of the ripplon was employed to fit the experimental power spectrum of overdamped ripplon to viscosity up to 1000 cS.