{'fraction_non_alphanumeric': 0.017847485127095726, 'fraction_numerical': 0.030827474310438075, 'mean_word_length': 4.589123867069486, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Design, fabrication, and test on an x-ray supersmooth toroidal mirror

Beijing Electron Positron Collider set up by High Energy Physics Institute in 1988 is one of the greatest scientific engineering in China and Beijing Synchrotron Radiation Lab. was set up in 1989. One of its seven light beamlines set up in 1990, i.e. 4B9B is used for experiment of synchrotron radiation X-ray photoemission energy spectra. The front focus mirror of the light beamline 4B9B is a supersmooth toroidal mirror at a distance of 11900 mm from synchrotron radiation source. The light beamline is at grazing angle of 3 degree(s) with respect to the surface of the supersmooth toroidal mirror and received angles in both horizontal and vertical directions are 4.5 mrad and 1 mrad respectively. The light beam is focused by the toroidal mirror and meridian plane is imaged on entrance slit S1 of spherical grating monochromator. Image distance of meridian plane is 6025 mm and image distance of sagittal plane is 13155 mm. The dimension of the mirror is 230 mm X 80 mm X 35 mm. The curvature radii of the meridian and sagittal planes are 152860 mm and 654 mm respectively. The paper describes optical system design, the technical characteristic, fabrication technique and improved machine tool and test methods on the supersmooth toroidal mirror. We have improved a machine tool to universal machine tool for machining aspherics. A series of aspherics have been tested by means of directly imaging. Results for testing profile of the mirrors and the radii by both meridian and sagittal planes indicate that blur circle of image is less than 0.1 mm in diameter, error of the radii is +/- 1 approximately 2% and surface roughness is 0.5 nm RMS. The technical specification meets requirements of users and has reached advanced level in the world on the same products abroad.