Diagram of a molecule of ultritium compund 902
A type 12 Hillebrand detonator was a device that could be used to activate certain chemical substances, like Ultritium compound 902.
In 2367, ultritium compound 902 was stored on board the Federation starship USS Enterprise-D in an inert liquid form. In order to activate the compound, an energetic gamma pulse, emitted by a type 12 Hillebrand detonator, could be used. (TNG-R: "Night Terrors")
This detonator was mentioned in the graphics created for the remastered episode. It was named after Jörg Hillebrand.