Spark Optical Emission Spectroscopy (Spark OES) involves placing detection electrodes in a vacuum chamber, applying high-voltage pulses to generate a spark that ablates the solid surface and creating a plasma. By collecting and analyzing the plasma spectrum, information on changes in the composition of the solid surface can be obtained, enabling real-time, in-situ diagnostics of the vacuum chamber surface. The technology serves as a complement to LIBS and offers advantages such as portability, freedom from window view angle restrictions, and independence from window transmission effects, making it a valuable tool for surface diagnostics.