ABSTRACT
The optical design and performance of the recently opened 13A biological small-angle X-ray scattering (SAXS) beamline at the 3.0â GeV Taiwan Photon Source of the National Synchrotron Radiation Research Center are reported. The beamline is designed for studies of biological structures and kinetics in a wide range of length and time scales, from angstrom to micrometre and from microsecond to minutes. A 4â m IU24 undulator of the beamline provides high-flux X-rays in the energy range 4.0-23.0â keV. MoB4C double-multilayer and Si(111) double-crystal monochromators (DMM/DCM) are combined on the same rotating platform for a smooth rotation transition from a high-flux beam of â¼4 × 1014â photonsâ s-1 to a high-energy-resolution beam of ΔE/E ≃ 1.5 × 10-4; both modes share a constant beam exit. With a set of Kirkpatrick-Baez (KB) mirrors, the X-ray beam is focused to the farthest SAXS detector position, 52â m from the source. A downstream four-bounce crystal collimator, comprising two sets of Si(311) double crystals arranged in a dispersive configuration, optionally collimate the DCM (vertically diffracted) beam in the horizontal direction for ultra-SAXS with a minimum scattering vector q down to 0.0004â Å-1, which allows resolving ordered d-spacing up to 1â µm. A microbeam, of 10-50â µm beam size, is tailored by a combined set of high-heat-load slits followed by micrometre-precision slits situated at the front-end 15.5â m position. The second set of KB mirrors then focus the beam to the 40â m sample position, with a demagnification ratio of â¼1.5. A detecting system comprising two in-vacuum X-ray pixel detectors is installed to perform synchronized small- and wide-angle X-ray scattering data collections. The observed beamline performance proves the feasibility of having compound features of high flux, microbeam and ultra-SAXS in one beamline.
Subject(s)
Photons , Synchrotrons , Scattering, Small Angle , Taiwan , X-Ray Diffraction , X-RaysABSTRACT
A novel monolithic mechanical bender has been designed and fabricated to meet the requirements of an active polynomial grating in a new soft X-ray scattering and emission beamline at the National Synchrotron Radiation Research Center, Taiwan. This compact bender achieves nearly fixed center point under different bending conditions. Moreover, the compact bender can be bent to a desirable third-order polynomial surface profile to cancel the defocus and coma aberrations using two PZT actuators. Theoretical analysis reveals that the grating has unprecedented spectral resolving power. A detailed mechanical analysis has been conducted and a prototype bender was fabricated and tested. The results indicate that the performance of the bender is excellent and is therefore suitable to be used in the active grating.
Subject(s)
Equipment Failure Analysis , Optics and Photonics/instrumentation , Scattering, Radiation , Synchrotrons/instrumentation , X-Ray Diffraction/instrumentation , X-Ray Diffraction/methods , Computer-Aided Design , Elasticity , Equipment Design , Feedback , Motion , Physical Stimulation/instrumentation , Stress, Mechanical , TransducersABSTRACT
A compact mirror manipulator which has high stiffness and is easily adjustable has been developed for new beamlines at SRRC. It consists of a vertical stem to support the mirror and allows for six-axis precise positioning. The rotation adjustment is designed with a minimum of cross-coupling between adjustments. An independent support is fixed to the ground to reduce vibration from the chamber and the pump. Some performance test results in vacuum and in atmosphere, including vibration, repeatability, long-term drift etc., are described in this paper.
