Note: Refined possibilities for plasma probe diagnostics

In an earlier publication, the ion mass determination technique was proposed using the Langmuir probe measurement results for low-pressure Maxwellian plasmas and their analysis, based on the Bohm effect and the Child-Boguslavsky-Langmuir (CBL) probe sheath model, allowing for probe sheath thickness and ion mass evaluations after the Bohm coefficient C BCyl ≈ 1.13 for cylindrical probes had been determined. In the present study, the step-front sheath model, being physically closer to the reality of gas discharge plasmas, was considered in order to correct the CBL sheath model results. At this stage, more real Bohm coefficient (C BCyl ≈ 1.23) for cylindrical probes was found to provide a more reliable method of probe sheath thickness and ion mass determination.