For examination of the deflection of the electron beam in a magnetic field. Particularly suitable for determining e/m in a homogeneous magnetic field generated by Helmholtz coils. Spherical glass flask containing i.a. an electron gun with indirectly heated cathode and anode with holes. The glass flask is filled with neon of low pressure. The gas atoms are ionized by the electrons and are thus excited so that light can be emitted. Therefore, a visible luminous beam is formed along the path of the electrons.

The narrow beam can be deflected into a closed circle by means of the homogeneous magnetic field formed by a pair of Helmholtz coils. The tube is provided with an internal measuring scale which means that an accurate and parallax-free determination of the diameter of the circle can be performed. The pipe is mounted standing on a base plate with connectors.

Specifications

Anode voltage: 200 to 300 V
Anode current: less than 0.3 mA
Glow voltage: 4 to 12 V, DC