Measured conversion efficiencies of P45, paraterphenyl, tetraphenyl butadiene, and sodium salicylate posphors in the soft-x-ray wavelength range

This paper presents a measurement of the conversion efficiency of P45 phosphor screens at 9.89, 23.6, 44.7 and 160 A and those of paraterphenyl, tetraphenyl butadiene and sodium salicylate at 9.89, 44.7 and 67.6 A. The conversion efficiency (CE) is defined as the ratio of the photoelectrons ejected from the photocathode of a visible detector, excited by the scintillated photons emitted from the phosphor in a solid angle 2π, to the number of soft-x-ray photons incident on the phosphor. This is done by calculating the optimal phosphor screen thickness, fabricating the thinnest phosphor screens and measuring their CE's.