The SGM4 beamline on ASTRID2
Specifications of the AU-SGM4 beam line
The SGM4 beamline is a modified version of the I4 Beamline from Maxlab, Sweden, which has been repurposed for use on the ASTRID2 synchrotron. The first horizontal focussing mirror (HFM) is shared with the SGM3 beamline and can be rotated to direct the beam down either beamline. The vertical focussing mirror (VFM) through to the exit slit are the same as used on I4 at Maxlab.
A sketch of the SGM4 beamline, which follows from the U55 undulator insertion device, is shown below. The beam polarisation is fixed to be horizontal.
A schematic diagram showing the optical layout of the AU-SGM4 beam line on ASTRID2.
The HFM and VFM focus onto the monochromator entrance slit. The monochromator is a single spherical grating design for high transmission, which directs the beam onto a moving exit slit to maintain the monochromator focus. A choice of three gratings covering low (LEG), (12-45 eV) medium (MEG) (35-105 ev) and high (HEG) (75-145 eV) energy ranges are available, with 300, 700, 1500 lines/mm respectively. Calculated values for the resolution on each grating over the full energy ranges are given below.
Resolution of the 3 SGM4 gratings.
Following the exit slit, an in-line gas cell allows for the characterisation and calibration of the monochromator. After the gas cell, two plane elliptical post focussing mirrors (PFM) direct the beam towards the end station to produce an intermediate focus 750 mm before the measurement position. This beam then diverges onto the final focussing element inside the end station, which is described in this page.
For further information please contact:
Søren Ulstrup
Jill Miwa
Last Modified 23 October 2023