Specific charge of the electron e/m

I. Principle Electrons are accelerated in an electric field and enter a magnetic field at right angles to the direction of motion. The specific charge of the electron is determined form the accelerating voltage, the magnetic field strength and the radius of the electron orbit. II. Task Observe the deflexion of electron beam in the electric field.Observe the movement of electron beam in the magnetic field (in the action of Lorentz force).Determination of the specific charge of the electron (e/m) .