Highly evacuated electron tube for demonstrating the wave nature of electrons through the observation of interference caused by passage of electrons through a polycrystalline graphite lattice (Debye-Scherrer diffraction) and rendered visible a fluorescent screen. Also intended for determining the wavelength as a function of the anode voltage from the radii of the diffraction rings and the lattice plane spacing of graphite, as well as confirming de Broglie’s hypothesis.

Specifications:
Max. filament voltage: 6.3 V AC
Max. anode voltage: 5 kV
Anode current: approx. 0.1 mA at 4 kV
Lattice constant of graphite: d₁₀ = 0.213 nm; d₁₁ = 0.123 nm