Shows beam-centric organisation of the system dictated by neutron flow ports (as opposed to assembly-centric organisation). The monochromator shield assembly is screwed to a concrete floor, the monochromator assembly (including goniometer) rotates with a monochromator shield drum assembly (which is partly inside and partly outside of the fixed monochromator shield assembly), and the beam passes through both “fixed” and “moveable” parts. The use of flowports helps to organise the model according to the logic of the beam. Note the difficulty in reflecting the horizontal beam path concisely.
Note also the lack of direction on the typed 'rotates with' and 'is mounted inside' connections compared with the "directed" association names.
Note that this notation precedes the introduction of the early Systems Modeling Language (SysML®) "FlowPort" (which is now achieved since SysML1.4 using FlowProperties on Block).