D33 - Massive dynamic q-range small-angle diffractometer
Inside of the casemate, i.e. the housing where the beam is tailored to satisfy the needs of either the 'monochomatic' or the 'time-of-flight' mode of operation of D33.
The neutrons arrive from the right side and go the sample and the detector on the left side. In between, they successively cross a velocity selector (not visible on the photo) and four choppers. The boxes between the choppers are a polariser and a wavelength filter.