A Diode Intensifier Tube Designed for Scintillation Detection

An input and output faceplates diode intensifier tube having a large ratio (.8) "useful-external diameters" has been designed with a view to reach very good performance in scintillation detection. The photoelectrons emitted by the bialkali photocathode are accelerated up to about 10 kV and collected on a fast blue phosphor screen (P 47). The design is described and the main technological problems which has to be solved are reported, in particular the one allowing to overcome wall charge effects. The experimental results on image distortions, electron and photon gains, single electron resolution, dark noise, as well as on the phosphor screen characteristics are given. An assembly of this tube working as a high photon gain (¿30 at 10 kV) light pre-amplifier, optically coupled to a fast photomultiplier could allow to obtain significant improvements of the FWHM energy resolution in scintillation detection by using a rather large NaI(T1) scintillator block (e.g. 9.4 % at 122 KeV instead of 10.5 % obtained with the fast PMT used alone).