Beamline Optical Layout
The beamline collects the infrared synchrotron emission from both edge radiation (ER) and bending magnet radiation (BM) of SPS-I where the synchrotron radiation is emitted from electrons traveling around the storage ring at nearly speed of light through a modified dipole chamber with opening-angle acceptance of 70H x 20V mrad^2 after the bending magnet.
Behind the tunnel wall, the synchrotron light which covers a spectrum of electromagnetic waves from infrared to hard X-rays impacts on the first slotted flat mirror located at 45° angle in the horizontal plane laterally to the direction of synchrotron beam to reflect only the infrared beam including visible light. Then the second and third mirrors which are cylindrical shape are used to focus the beam horizontally and vertically, respectively. The fourth mirror delivers the beam through the wall tunnel. After that, the fifth – ninth mirrors positioned in a M5-M9 chamber are responsible to collimate and split the beam to accommodate up to 3 branches. Then a matching optical box is used to reduce the beam size before deliver the beam into the spectrometer.
Once the beam enters into the FT-IR spectrometer, Vertex 70 with assistance of the motorized matching box, and the Hyperion 2000 microscope coupling to the Vertex 70 focuses the IR beam in a wavenumber range of 4000 - 400 cm-1 to micro-scale beam size. The beam size at sample position will additionally be adjusted by an auto-aperture system in the Hyperion 2000 with respect to a size of the sample.
Endstation
The experimental station is equipped with a Vertex 70 FTIR-spectrometer and a fully automated microscope – Hyperion 2000 (Bruker) with a single point Mercury cadmium Telluride detector (MCT detector). When a SR beam exits from the M5-M9 chamber, the matching optical box generates to reduce beam size and delivers the beam from the chamber into the Vertex 70.
After that, those analytic instruments optimize the mid-IR beam proper to characteristics of each sample using OPUS software. The features in the OPUS software include data acquisition, data processing, evaluation, and report generation that users can request to access to process IR spectrum during or off beamtime by on-site or VPN if required.
Performance
The optical performance of the IR beam on sample is mainly relied on a size of aperture within Bruker's spectroscopy, Hyperion 2000 which is varied from 5 to 50 microns depending on sample. Thus, how SR source is recommended over internal source for IR microspectroscopy.
