Calculation of cathode heating in analytical glow discharges†
The temperature of the cathode (sample) in analytical glow discharges is calculated as a function of depth in the sample, by means of a one-dimensional heat conduction equation. The energy input is determined by the energetic ions and atoms bombarding the cathode. Calculations are performed for a Cu sample, under various conditions, ranging from perfect cooling from the backside, to the limit of no cooling. The effect of the discharge conditions (voltage–pressure–current) is also investigated. Finally, simulations are carried out for various cathode materials. It is found that the efficiency of cooling has a very important effect on the cathode surface temperature. Moreover, different cathode materials can give rise to great differences in the cathode surface temperature for the same power input, due to a different thermal conductivity.