Page 133 - Neutrons for Sciences and Society

Chapter 5: The construction of the reactor and the scientific groups
Fig. 5.12: Sketch representing the reactor in its building with the neutron guides exiting into a separate building. Some instruments are shown. Again this is from the early days. Since then a new cold source has been added which feeds guides entering a new hall situated behind the reactor as shown here.
At the ILL 10 guides were installed at the start, 5 viewing
the cold source (H1) and 5 in the reflector tank (H2) delivering thermal neutrons. They exit from a single combined nose-port in the reactor vessel (H1/H2). Eight (4+4) of these guides terminate outside the reactor building in an adjacent building known as the Guide Hall, which is 90 m long and 35 m wide (Fig. 5.12, Fig. 5.13). They are slightly curved to reduce the background with the radii varying from 25 m to 27 km. The whole installation comprises 473 m of main guides with another 120 m of channels
124