Fluorescence efficiencies of thin scintillating films in the extreme ultraviolet spectral region

Fluorescence efficiencies of the organic scintillators tetraphenyl butadiene (TPB), p-terphenyl (TPH), and diphenyl stilbene (DPS) are measured relative to sodium salicylate at incident wavelengths of 58.4 and 74.0 nm. Optimum thickness and dopant concentration are determined for maximum fluorescence yield in evaporated, sprayed, and doped plastic films. Measurements made with alpha (a) particle induced scintillations in gaseous argon (a broad band vacuum ultraviolet light source) were in good agreement with those made using the line source. Transparent scintillator doped plastic films have been developed which yield fluorescence efficiencies comparable to that of sodium salicylate. Evaporated films show the highest fluorescent yields, reaching almost four times the efficiency of sprayed sodium salicylate. On the other hand, doped plastic films offer some advantages.