The radiation for our beamline comes from the first dipole (bending magnet) in sector two of the storage ring.
The shape of the beam comes out in two parallel stripes due to the first mirror (M1) in the storage ring which has a slit in the middle to allow the higher energy radiation to pass through.
Figure: M1 mirror with central slit
Figure: M1 mirror pre-installation on insertion arm
Figure: Shape of the beam in the matching optics box (visible light)