Combined pressure and flow sensor integrated in a split-ring resonator microplasma source

Abstract

Monitoring and control of the principal properties of a discharge or plasma is vital in many applications, and sensors for measuring them must be integrated close to the plasma source in order to deliver reliable results. This is particularly important, and challenging, in miniaturized systems, where different compatibility issues set the closest level of integration. In this paper, a sensor for simultaneous measurement of the pressure and flow through a stripline split-ring resonator microplasma source is presented. The sensor utilized the fully integrated electrodes positioned upstream and downstream of the microplasma source to study these parameters and was found to deliver uniform and unambiguous results in the pressure and flow range of 1–6 Torr and 1–15 sccm, respectively. Furthermore, hysteresis and drift in the measurements were found to be mitigated by introducing a resistor in parallel with the plasma, in order to facilitate the discharging of the electrodes. Together, the results show that the sensor is fully compatible with the miniaturized microfluidic systems in general and a system for optogalvanic spectroscopy in particular.