Fig. 2: Image of the full prototype equipped with two photomultiplier tubes.
From: Next-generation neutron detection using a 6Li glass scintillator composite

Here, the 6Li glass scintillator composite is seen luminescing in a purple color under the illumination with ultraviolent light (optical excitation of Ce3+ in the 6Li glass scintillator). The cadmium sheet and the optical reflector surrounding the tube containing the 6Li glass (GS20TM)/mineral oil (Drakeol®9LT) composite were removed for this picture. The length of the cylindrical composite is shown for scale.