Optical

Nano Shape Measurement Technologies for High-Precision X-Ray Mirrors (MSI/RADSI・CMM・CGHI)

To manufacture high-precision X-ray mirrors with nano-order shape errors—equivalent to a variance of just a few atoms—ultra-high-precision measurement delivering exceptional accuracy and reproducibility is indispensable. As a beamline optics supplier dedicated to precision mirror fabrication, JTEC manufactures high-precision synchrotron mirrors utilizing advanced MSI, RADSI, CMM, and CGHI measurement technologies. These optics have earned high acclaim from major synchrotron radiation facilities worldwide.

MSI & RADSI

MSI and RADSI, which are nano-measurement technologies of JTEC CORPORATION, are surface shape nano-measurement methods researched and developed by Professor Kazuhito Yamauchi of The University of Osaka and are indispensable technologies for the production of high-precision X-ray mirrors.

MSI(Microstitching Interferometry)

MSI is a technology that evaluates surface roughness by measuring a minute area with a Michelson-type phase-shift interferometer. It measures the nano shape of the entire mirror by a stitching mechanism. In X-ray mirrors, nano-level surface roughness (high-frequency components) significantly affects reflectance. However, due to errors caused by the stage mechanism, MSI has a limit to its measurement accuracy of large waviness (low frequency component) of the entire mirror.

RADSI(Relative Angle Determinable Stitching Interferometry)

RADSI is a technology that offers a unique stitching mechanism for Fizeau interferometry, and measures the overall shape data by gradually tilting the measurement surface and connecting the acquired measurement data. In X-ray mirrors, the large waviness of the entire mirror significantly affects the light collection size. RADSI enables nano-order shape measurement even for aspherical shapes that have been difficult to measure thus far.

JTEC CORPORATION combines MSI and RADSI measurement data (MSI high-frequency component and RADSI low-frequency component) to minimize the measurement error of all spatial wavelengths in the shape measurement of the entire X-ray mirror at nano scale. This is the advanced realization of shape measurement.

In collaboration with The University of Osaka, we have developed in-house automated system using MSI and RADSI to improve the mirror production efficiency. We have obtained numerous patents for this technology in collaboration with The University of Osaka.

In addition, we have independently developed measurement technology for long mirrors, for which demand is growing. To date, we have achieved nanometer-order shape measurement for aspherical mirrors up to 1 m long.

MSI Measurement System
RADSI Measurement System

CMM (Coordinate Measuring Machine): Nano 3D Shape Measurement Technology

Our proprietary 3D Coordinate Measuring Machine (CMM) utilizes a laser probe to enable non-contact height measurement. By employing an ultra-high-precision plane mirror—manufactured using our X-ray mirror fabrication technology—as the measurement reference, the control precision of the measurement posture has been significantly enhanced. This advancement enables nano-order shape metrology for mirrors with small radii of curvature and steep profiles (such as sagittal cylindrical, toroidal, and sagittal elliptical mirrors), which was previously unattainable with conventional interferometric methods.

(CGHI) Computer Generated Hologram Interferometry

Computer Generated Hologram (CGH) interferometry is a technology that uses diffractive optical elements to transform the plane waves of a Fizeau interferometer into wavefronts that match the designed profile of a mirror. This allows for the high-speed and high-precision acquisition of surface figure error data across extensive areas of 2D curved mirrors, including aspherical and freeform surfaces. JTEC Corporation has developed a CGH interferometry system by integrating our proprietary stitching technology, refined through MSI and RADSI, with the latest optimization algorithms. This system enables the extremely accurate measurement of surface profiles across a wide range of spatial wavelengths, from sub-millimeter to several hundred millimeters. Furthermore, by complementarily combining CGH with CMM and MSI metrology techniques, we have minimized measurement errors across all spatial frequency ranges, achieving nano-order, ultra-high-precision shape measurement even for long 2D curved mirrors with lengths up to 1 meter.

CGHI (Computer Generated Hologram Interferometry)

FAQ

Could you please explain the differences between MSI and RADSI?

The biggest difference lies in the "measurement range and spatial resolution" that each system covers.
MSI: Measures the "micro-smoothness (surface roughness)" of the mirror surface using a microscopic interferometer.
RADSI: Measures the "macro-waviness (figure error)" across the entire mirror. In order to focus X-rays precisely as intended, it measures the overall curvature of the mirror with high precision.

How much time is required for the measurements?

Depending on the size of the mirror, measurements are meticulously performed over a period of several hours, or in some cases, up to several days. This is because "uncompromising metrology" is indispensable to guarantee sub-nanometer precision. This precise data serves as the driving force behind the creation of the world's finest X-ray mirrors.

What exactly is "stitching measurement"?

"Stitching measurement" is a method of precisely piecing together localized high-resolution data like a puzzle, and its application and advancement for X-ray nanofocusing optics were realized at the University of Osaka. By integrating the micro-perspective of "MSI" with the macro-perspective of "RADSI," the entire surface of a mirror, even one exceeding 1 m in length, can be evaluated with nanometer-scale resolution. This technology, which bridges the gap between wide-area and fine-scale measurements, is our unique, world-exclusive core technology that supports our quality.

Were the MSI and RADSI systems developed in-house?

Yes. We design and develop the measurement equipment itself in-house. Commercially available measuring instruments have their limits when it comes to accurately evaluating sub-nanometer precision. Driven by the conviction that creating the ultimate mirror requires building the "ultimate ruler (equipment)" ourselves, we have established a unique, globally unparalleled measurement system through collaborative research with the University of Osaka.