Discharge tube, canal rays

For observing the characteristic, pressure-dependent luminous phenomena occurring during electric discharges in rarefied gases, and for investigating cathode and anode rays which occur at sufficiently low pressure (≤3 x 10^-2 mbar) outside the discharge path, beyond the perforated aluminium electrodes.
The end caps of the tube are coated with fluorescent material. Please note:
During operation with the high-voltage power supply unit 10 kV (521 70), the x-radiation emitted by the tubes stays below the maximum permissible limit. >Even at low pressures, the dose rate of x-rays in the cathode radiation zone is less than µSv/h at a distance of 0.1 m from the contact surface. For this reason, the tubes do not need to be registered as dangerous radiators according to German legislation.