To produce infrared light up to 280 μm a hybrid undulator (U100) has
been installed at the radiation source ELBE. It consists of 38 periods
each 10 cm long with Sm2Co17 magnets and soft-iron poles.
The undulator gap can be varied from 24 mm to 150 mm by means of a
girder system. The resulting undulator parameter varies from 2.7 to 0.3.
To let pass radiation longer than 40 μm through the undulator gap a partial waveguide was installed. It spans from the upstream undulator entrance to the downstream mirror.