2020同步年報

110 ACTIVITY REPORT 2020 high flux, USAXS, anomalous SAXS (ASAXS) and microbeam are designed to have essentially overlapped beam paths, al- lowing convenient mode conversions. Four diamond X-ray beam-position monitors (XBPM) are deployed along the beamline, reporting beam positions at the front-end before any optical component and in the experimental end-station before the sample position, in situ and on-line, with beam position resolution 1 µm. Optical designs of the operation- al modes ( Fig. 1 ) were detailed in a previous report; 1 the corresponding feature parameters are listed in Table 1 . All beamline and end-station components are controlled with an experimental physics and industrial control system (EPICS), which governs all interfacing among the electronic hardware of the beamline through defined process variables (PV) and a server program of input/output controllers (IOC). At beamline TPS 13A , there are two clients of PV. The first is the graphical user interface called control-system studio (CSS), which serves mainly the configured icon display and remote control of the beamline components (real and virtual motors) and their current status and historical data records. The second client is SPEC software that allows multi-task macros to execute routine procedures, such as alignments of the beam positions, intensity optimization, beam energy changes and optical mode conversions. Shown in Fig. 2(a) are the closely matched calculated and measured profiles of photon flux of the 3 rd and 5 th har- monic modes (HM) of IU24 at gap 8 mm, at 30 mA of the Fig. 2 : (a) Measured flux spectra of the 3 rd and 5 th harmonic modes of the undulator IU24 at gap 8.0 and 8.7 mm, centered respectively at 7.376 keV and 4.998 keV; the data are fitted (solid curves) using Spectra software with an electron beam of 30 mA, 3GeV, and a common electron-beam energy spread of 0.11%. (b) Flux spectra measured 40 m from IU24 at the sample position at e-beam current 400 mA, using the DMM and DCM mono- chromators, respectively. Also shown are the consistently simulated flux profiles. (c) Simulated beam-size and –divergence evolutions over X-ray beam path 52 m from the IU24 (origin) to 52 m. (d) Beam sizes measured over 10 m sample-to-detector distance, using the Eiger X 9M detector (pixel size 75 μm). Table 1 : Features of operational modes of TPS 13A , with IU24 source sizes 283 × 7.5 μm 2 (FWHM) and source divergence 45 × 21 μrad (FWHM). The microbeam features are calculated with microslit openings 10 µm by 10 µm. Operational modes High flux (DMM) USAXS Si(111) ASAXS (DCM) µ−beam (DMM) Operation energy range (keV) 7−15 4−15 4−23 7−15 Horizontal demagnification 1.36 : 1 1.61 : 1 Vertical demagnification 1.43 : 1 1.45 : 1 Beam size (μm 2 at 40 m) 190 × 52 190 × 36 190 × 36 7 × 5 at 40 m Divergence (μrad) 60 × 29 32 × 29 60 × 29 70 × 3.8 Energy resolution ~0.2 % ~0.02 % Flux (photons/s) @ 500mA ~4 × 10 14 ~4 × 10 12 ~2 × 10 13 ~1 × 10 10