Kazuhiro Enami

Belle II silicon vertex detector

The Belle II experiment at the SuperKEKB collider in Japan is designed to indirectly probe new physics using approximately 50 times the data recorded by its predecessor. An accurate determination of the decay-point position of subatomic particles such as beauty and charm hadrons as well as a precise measurement of low-momentum charged particles will play a key role in this pursuit. These will be accomplished by an inner tracking device comprising two layers of pixelated silicon detector and four layers of silicon vertex detector based on double-sided microstrip sensors. We describe herein the design, prototyping and construction efforts of the Belle-II silicon vertex detector.

Development of surface gradient integrated profiler - Precise coordinate determination of normal vector measured points by self-calibration method and new data analysis from normal vector to surface profile -

A new ultra-precision profiler has been developed to measure items such as asymmetric and aspheric profiles. In the current study, the normal vectors at each point on the surface are determined by a reflected light beam that returns along exactly the same path as the incident beam. The surface gradients at each point are calculated from the normal vector, and the surface profile is obtained by integrating the gradient. At a previous meeting, we reported that normal vector measured points with submicron accuracy can be determined by a self-calibration method. In this paper, the self-calibration method has been tested and shown to have the capability for surface profile measurement accuracy of nanometer order, using a concave mirror with a radius curvature of 2000 mm. The precise surface profile obtained from a measured normal vector has been studied as a new data analysis method that applies Fourier series expansion with the least-square method. Future development will include the following: the elimination of error propagation due to data analysis from normal vector to surface profile, unique determination of profile from normal vector, and enabling random measuring position of normal vector on the mirror.

Surface gradient integrated profiler for X-ray and EUV optics

Abstract A new ultraprecise profiler has been developed to measure, for example, asymmetric and aspheric profiles. The principle of our measuring method is that the normal vector at each point on the surface is determined by making the incident light beam on the mirror surface and the reflected beam at that point of coincident. The gradient at each point is calculated from the normal vector, and the surface profile is then obtained by integrating the gradients. The measuring instrument was designed in accordance with the above principle. In the design, four ultraprecise goniometers were applied to adjust the light axis for normal vector measurement. The angle-positioning resolution and accuracy of each goniometer are, respectively, 0.018 and 0.2 μrad. Thus, in the measuring instrument, the most important factor is the accuracy of the normal vectors measured by the goniometers. Therefore, the rotating angle-positioning errors were measured and calibrated. An elliptical profile mirror for nanometer hard-X-ray focusing was measured, and compared with the measured profile using a stitching interferometer. The absolute measurement accuracy of approximately 5 nm (peak-to-valley) was achieved. Then the measurements of 1000-mm-long flat, spherical and parabolic mirrors were demonstrated. The surface profiles of the mirrors were obtained by integrating the interpolated gradient.

A new designed ultra-high precision profiler

A new ultra-precision profiler was developed to measure X-ray and EUV optics such as asymmetric and aspheric profiles. In the present study, the normal vectors at each point on the surface are determined by a reflected light beam that follows exactly the same path as the incident beam. The surface gradients at each point are calculated from the normal vector and the surface profile is obtained by integrating the gradient. The measuring instrument was designed according to the above principles. In the design, four goniometers and three-axis movers were applied to adjust the light axis to search for the normal vector at each point on the surface. The angle-positioning resolution and accuracy of each goniometer are respectively 1.8 x 10-8 radian and 2 x 10-7 radian. A SiC flat mirror 25.4 mm in diameter and an elliptical profile mirror for nanometer hard X-ray focusing were measured using the present instrument and compared to the measured profile using a Zygo Mark IVxp phase-measuring interferometer.

Surface gradient integrated profiler for x-ray and EUV optics: 3D mapping of 1m-long flat mirror and off-axis parabolic mirror

A new ultra-precision profiler has been developed in order to measure such as asymmetric and aspheric profiles. In the present study, the normal vectors at each points on the surface are determined by the reflected light beam goes back exactly on the same path as the incident beam. The surface gradients at each point are calculated from the normal vector and the surface profile is obtained by integrating the gradient. The measuring instrument was designed according to the above principle of the measuring method. In the design, four ultra-precision goniometers were applied to the adjustment of the light axis for the normal vector measurement. The angle positioning resolution and accuracy of each goniometer are respectively 0.018 μrad and 0.2 μrad. In the measuring instrument, the most important item is the measuring accuracy of the normal vectors by the goniometers. Therefore, the rotating angle positioning errors were measured and calibrated. Then the measurement of a concave mirror with 300 mm radius and 460mm, 1m long plane mirrors were measured. Then, The 3D surface profile of the mirror such 1m-long flat mirror, a concave mirror with 2000 mm radius and off-axis parabolic mirror are obtained by integrating the interpolated gradient.

High-precision profile measurement of a small radius lens by surface gradient integrated profiler

A new concept profiler has been developed to measure items such as asymmetric and aspheric profiles with a small radius curvature lens and mirrors. In this study, the normal vectors at each point on the surface are determined by a reflected light beam that returns along exactly the same path as the incident beam. In order to measure a small radius curvature, a compact measuring instrument was redesigned according to the above principle of the measuring method employed. The instrument is 1200 mm (W) × 1000 mm (H) × 1500 mm (V). The measurement of normal vectors of a spherical lens, which has a small f number such as a 25 mm radius curvature, has been demonstrated with a measuring accuracy for the normal vector of 0.1 μrad. The surface gradient at each point is calculated from the normal vector, and the surface profile is obtained by integrating the gradient. When integrating the gradient, measured position accuracy should be in the order of 10 nm. They were obtained by self-calibration techniques that have already developed by the authors. In this paper, we discuss methods of calculating absolute radius curvature and deviation from the ideal surface profile.

Surface Gradient Integrated Profiler for X‐ray and EUV Optics—Calibration of the rotational angle error of the rotary encoders

A new ultraprecision profiler has been developed to measure for example asymmetric and aspheric profiles. The principle of our measuring method is that the normal vector at each point on the surface is determined by making the incident light beam on the mirror surface and the reflected beam at that point coincident. The gradient at each point is calculated from the normal vector, and the surface profile is then obtained by integrating the gradients. The measuring instrument was designed in accordance with the above principle for the measuring method and is called Surface Gradient Integrated Profiler (SGIP). In the design, four ultraprecision goniometers were applied to adjust the light axis for the normal vector measurement. These goniostages make it possible to attain an angular resolution of 0.018 μ radian by electrically dividing a pulse of the rotary encoder. The surface gradients are determined only by the rotational angle of goniometers. Thus in the measuring instrument, the most important factor is...

Surface gradient integrated profiler for x-ray and EUV optics: self calibration method of measured position for an off-axis parabolic mirror (f=150mm) measurement

A new ultra-precision profiler has been developed in order to measure such as asymmetric and aspheric profiles. In the present study, the normal vectors at each points on the surface are determined by the reflected light beam goes back exactly on the same path as the incident beam. The surface gradients at each point are calculated from the normal vector and the surface profile is obtained by integrating the gradient. The measuring instrument was designed according to the above principle of the measuring method. In the design, four ultra-precision goniometers were applied to the adjustment of the light axis for the normal vector measurement. In the measuring instrument, the angle-positioning resolution and accuracy of each goniometer are respectively 1.8x10-8rad and 2x10-7rad. A coaxial with an off-axis parabolic mirror has been developing for applying as an optical cavity. The most important engineering technique is to measure the profile of the reflective surface with sub nanometer. The present measuring instrument is evaluating to have capability to the surface measuring accuracy with nanometer for such parabolic mirror profile measurement. A coaxial off-axis parabolic mirror with 150 mm focal length has been polished. The outside and inside diameter of the mirror is 360 mm and 258 mm respectively. The thickness of the coaxial direction is 50 mm. The focal point is located on the center of the coaxial and the center of the coaxial direction of the mirror. The profile measurement such a mirror has been demonstrated. Specially, self calibration method for increasing the measured position accuracy from measured data is discussed.