Ion beam detector

Ion beam detecor for a mass-spectrometer is developed allowing one to sufficiently decrease the background current, due to tritium nucleus β-decay and increase the accuracy of chemical and isotopic analysis of gas mixtures containing tritium. The detector is based on the principle of ion transformation into secondary electrons with their subsequent transformation into the light quanta, which are registered by a photoelectron multiplier. The main peculiarities of the detector is the presence of a protective layer which is applied to the scintillator. A monolithic scintillating shield of CaF2(Eu) is used as a scintillator. The shield operating surface is coated with fp-25 photoresistor with the thickness of about 6.5 μm. In its turn the protective layer is coated with a thin Al layer with the thickness of <50 nm which is electrically connected to the detector casing. The protective layer arresrs β-electrons in the whole energy range. The detector complete background current value does not exceed (1.5-2)x10-17 A