Electron density measurements in low-pressure plasmas using cutoff probes and comparison with hairpin and Langmuir probes

We present a comparative study of electron density obtained in a low-temperature plasma by the cutoff probe and compare the results with data from both the hairpin and the Langmuir probes. The measurements with different probes were conducted in a DC discharge generated by an iron hollow cathode under identical experimental conditions. This comparative analysis provides insight into the reliability and consistency of electron density measurements across different probe types in this specific experimental setup. The information acquired from the cutoff and hairpin probes enables electron density measurements within the frequency range limitations of the instruments. Measurements of electron density are performed in a mixture of argon and oxygen at a low pressure of 5 Pa, in dependence on the discharge current and Ar:O-2 mixture ratio. A qualitative discussion of the obtained results is provided.