The measuring variables that particularly characterize plasma are electron temperature and emission of various species excited in the ultraviolet and visible range.
The only way to pretreat even very thermally sensitive plastics under atmospheric pressure without damage is by using high electron temperature and low ion temperature.
The luminous phenomena (optical emissions) of a relaxing* plasma can be detected with the use of optical emission spectroscopy (OES). To do this, characteristic emission bands of the species excited in the plasma in the visible, and especially in the ultraviolet, range of the spectrum are transmitted by an optical fiber to the evaluation electronics and then further processed with special software. The process monitoring components of the Plasmatreat systems operate according to this principle of optical monitoring. This allows for uniform quality over the entire plasma process.
* Relaxing: The transition of plasma into its basic state. In this process, the excitation energy that was previously supplied is released into the environment in the form of light.