Zinc Sulfide Phosphors for Neutron Detection
Figure 1: Silver Activated zinc sulfide powder
Figure 2: Silver activated zinc sulfide powder viewed under UV illumination
In this application, the silver activated zinc sulfide phosphor powder is intimately mixed with a Lithium-6 isotope enriched lithium fluoride powder, employing predetermined ratios for detection optimization, in an appropriate binder matrix to form a thin layer on a substrate. Neutrons incident on the screen impact the Li-6 isotope and the ensuing transmutation generates an alpha particle (helium atom) and a triton particle according to the following equation:
01n + 36Li ---> 13H + 24He + 4.78MeV
Subsequent collisions with either of these charged particles cause the silver activated zinc sulfide to scintillate and emit broad band emission centered on the blue region of the visible spectrum at 450nm.
The zinc sulfide powder is manufactured in the USA by the Lorad Corporation. It is available in commercial quantities.