Helium concentration measurements in an atmospheric micro-plasmas using visible emission spectroscopy

Summary form only given, as follows. A simple in-situ gas monitoring system can be developed with micro discharge plasma sources based on optical emission spectroscopy. Helium concentrations are estimated from the visible line emission of atmospheric plasmas generated with various micro plasma discharges. With this technique, volumetric helium concentrations are accurately measured even down to a percent. Since selected emission lines are not affected by moisture, this measuring system can be operated even without sampling and drying processes, which is a crucial element of in-situ monitoring system. The compact in-situ gas monitoring system will be presented, and the system is expected to be applicable to measuring other elements than helium.