Time resolved analysis algorithm for ramped Langmuir probe to study temporal evolution of plasma parameters in ROBIN

ROBIN (Rf Operated Beam source in India for Negative ion research) is an Inductively Coupled Plasma (ICP) device, which is powered by a 1 MHz Radio Frequency (RF) generator of 100 kW power. During the experiment in ROBIN source in IPR, plasma is monitored and characterized by two independent diagnostics based on optical emission spectroscopy (OES) and two separate Langmuir probes (LP) powered by ramped bias voltage. In the present work, an algorithm has been developed in LabVIEW to analyse the digitized LP signal to study the time evolution of different plasma parameters. The software is developed for both real time as well as post hoc analysis of Langmuir probe data and is normally applicable for low temperature, non magnetized, collisionless plasmas. The unprocessed LP data contains significant noise level and so noise filtration is adopted. In present case, Savitzky-Golay (SG) noise filtering method is used for data conditioning for its ability to preserve the area under the signal curve. The analysis software is implemented in ROBIN data acquisition setup to study the plasma evolution in ROBIN in-situ, to optimize the operational parameter regime.