Publications by authors named "Takehiro Kume"
Article Synopsis
- * The new method enhances mirror production by addressing issues like corrosion and thermal deformation, providing better stability and performance for high-quality x-ray optics.
- * A vacuum degassing technique was developed to reduce bubble pit formation during fabrication, resulting in the successful creation of three pit-free mirrors for the FOXSI-4 project, with precise accuracy and performance comparable to leading x-ray missions.
In this study, figure correction of a master mandrel of a Wolter mirror by organic abrasive machining (OAM) was demonstrated. In OAM, a flow of slurry, dispersed with organic particles, locally removes the surface of a workpiece in contact with a rotating machining tool. A computer-controlled machining system was used to perform the selective removal of a fused silica surface at a spatial resolution of 200 µm.
View Article and Find Full Text PDFA soft X-ray ptychography system using a Wolter mirror for the illumination optics has been developed. By taking advantage of the achromaticity of the optics, the system is capable of seamlessly imaging at half-period resolution of 50 nm with a broad photon-energy range from 250 eV to 2 keV while maintaining the focal position. Imaging a mammalian cell at various wavelengths was demonstrated, and high-resolution visualization of organelle was achieved.
View Article and Find Full Text PDFArticle Synopsis
- The Wolter mirror is a high-performance optical device designed for focusing soft x-rays to a very small spot size, with benefits like high efficiency and resilience against alignment errors.
- The study overcame challenges in creating this mirror by using tactile scanning measurements, which allowed for accurate surface characterization without damaging the mirror substrate.
- The final fabricated Wolter mirror showed minimal figure error, and simulations confirmed its ability to focus x-ray beams as expected, with experimental results validating the tactile measurement approach's effectiveness.
We developed a copper electroforming replication (CER) process to fabricate precise ellipsoidal mirrors for soft x-ray focusing. Some applications of ellipsoidal mirrors in x-ray microscopy require that all components that are close to samples, including the mirrors, are made of non-magnetic materials. In this study, a non-magnetic copper ellipsoidal mirror was fabricated by replicating a figured and super-polished quartz glass mandrel using an electroforming technique.
View Article and Find Full Text PDFWe developed a full-field microscope with twin Wolter mirrors for soft X-ray free-electron lasers. The Wolter mirrors for a condenser and an objective were fabricated using an electroforming process with a precisely figured master mandrel. In the imaging system constructed at SACLA BL1, sub-micrometer spatial resolution was achieved at wavelengths of 10.
View Article and Find Full Text PDFIntense sub-micrometre focusing of a soft X-ray free-electron laser (FEL) was achieved by using an ellipsoidal mirror with a high numerical aperture. A hybrid focusing system in combination with a Kirkpatrick-Baez mirror was applied for compensation of a small spatial acceptance of the ellipsoidal mirror. With this system, the soft X-ray FEL pulses were focused down to 480 nm × 680 nm with an extremely high intensity of 8.
View Article and Find Full Text PDFArticle Synopsis
- An x-ray ellipsoidal mirror is crucial for focusing soft x-rays, but creating one with the required nanometer-level accuracy is challenging, especially for small diameters.* -
- Researchers developed a method to fabricate these mirrors using nickel sulfamate electroforming on a high-precision quartz mandrel that has the mirror's inverted shape.* -
- A mirror measuring 40-mm in length was created, showing a replication error of 27.2 nm overall and 14.7 nm in the central area, enabling the potential to focus soft x-rays down to a 400 nm diameter spot.*
Fabrication of a precise ellipsoidal mirror for soft X-ray nanofocusing.
Rev Sci Instrum
September 2018
Article Synopsis
- Grazing incidence mirrors for X-rays are beneficial because they eliminate chromatic aberration and can focus efficiently.
- While there are existing nanofocusing mirrors for hard X-rays, soft X-ray mirrors with similar capabilities are lacking, particularly for focusing below 100 nm at energies under 1 keV.
- This study presents a new fabrication process for ellipsoidal mirrors, which achieved a focus size of under 250 nm at 300 eV, showing potential for advanced X-ray mirror designs, including Wolter mirrors.