Objects
Thermionic emission of electrons
Deflection of electrons in electron and magnetic field
Estimate of specific change of an electron e/m
Principles
The electron-beam deflection tube is intended for investigating the deflection of electron beams in electrical and magnetic fields. It can be used to estimate the specific charge of an electron e/m and to determine the electron velocity v. The electron-beam deflection tube comprises an electron gun which emits a narrow, focused ribbon of cathode rays within an evacuated, clear glass bulb. A tungsten filament hot cathode is heated directly and the anode takes the form of a cylinder. The deflection of rays can be achieved electrostatically by means of a built-in plate capacitor formed by the pair of deflection plates or magnetically with the help of the Helmholtz coils (P338002) magnetically.
The cathode rays are intercepted by a flat mica sheet, one side of which is coated with a fluorescent screen and the other side of which
is printed with a centimeter graticule so that the path of the electrons can be easily traced. The mica sheet is held at 15 degree to the
axis of the tube by the two deflecting plates.
