High-vacuum electron tube with divergent electron gun aimed at a fluorescent screen partially obscured by a Maltese cross. For demonstrating the linear propagation of electrons in the absence of applied electromagnetic fields by projecting the shadow of a Maltese cross onto the fluorescent screen. Application of a magnetic field using the Helmholtz Coils D allows for students to study the fundamental science of electron optics, such as beam focusing.SpecificationsMax. filament voltage: 7.5V AC/DCMax. anode voltage: 5 kV Anode current: 0.18mA at 4kV