Spatial Distributions of Excited Atoms in Argon Plasma

Plasma describes the property of ionized gas that follows the shape of the object where it was created. The interests in low-temperature plasma have been increasing over the years for uses in the biotech and semiconductor industry, making it essential for modern technology. Though it has become more commonly used in the industry the fundamental characteristics of plasma are still being researched, thus improving on understanding and controlling it is essential for the industry, which is why we have tried to observe and understand plasma characteristics. The experiment was conducted using pure Argon in a radio-frequency cavity discharge, using a commercial low-temperature RF generator operating at a frequency of 13.56 MHz, at powers of 30-100 W, and the working pressure in the quartz chamber of 15-50 mTorr. We created an automated optical measurement system for distance measurements, using two high precision stepper motors and translational stages operated by a Raspberry Pi. Using an optical emission spectrometer (OES) we were able to detect the various excited energy levels higher than ground and metastable states. We are using the OES as our primary measurement tool to observe the spectra of the argon excited states by measuring photons emitted from the plasma. We developed a robust 2D plasma tomography method to find spatial distributions of excited argon levels, as well as calculating the average of various levels. Through our measurement methods, we are able to collect the light of various wavelengths emitted from the plasma, through this we are able to determine plasma intensities, the population densities, graph robust two angle tomography, and electron configurations