WISH is a neutron diffraction instrument, which can be used to determine the atomic and or magnetic structure of a material.
As with the other instruments, the process starts with hydrogen ions, which are accelerated by the linear accelerator and synchrotron. In the synchrotron, the hydrogen ions are stripped of their electrons, leaving protons. The high energy protons bombard a tungsten target, releasing neutrons, which are then slowed down and a small proportion of which are directed towards the WISH instrument.
The neutrons travel at a high speed down the centre of WISH, until they collide with the sample. The neutrons exiting the sample have around the same energy as those entering it, a typical feature of neutron diffraction.
The sample under investigation is placed in a beam of cold neutrons. The intensity pattern around the sample provides information about the structure of the material.