The source of the SIM beamline is a pair of UE36knot (APPLE X type) undulators, which produce up to 1015 photons/second in a photon energy range of 260 - 1600 eV covering most relevant core levels from the C K-edge (280eV) up to the rare earth M-edges (~1600 eV) on the fundamental harmonic.
| Type | Elliptical twin undulator UE36knot (APPLE X type) |
|---|---|
| Period length | 36 mm |
| Number of periods | 51 |
| Gap | 11.5 - 30.5 mm |
| Polarization | Linear: 0o (horizontal), ±45o and 90o (vertical) Circular: right / left |
| Max. K value | 3.6 |
| Operating on harmonics | 1 |
| Maximum field | 1 T |
| Energy range | 260 - 1600 eV |
Figure 1: UE36knot (APPLE X type) undulator during construction in May 2024.