  Drug resistant bacteria, prions and nosocomial infections underline the need
of more effective sterilizing technologies. The cold plasma technology is
expected to bring a benefit in this context. Six different plasma sources,
based on printed circuit boards, were evaluated fourfold. This include
measurements of the power consumption, the ignition behavior by an ICCD-camera
and ozone formation by absorption spectroscopy at 254 nm. To evaluate the
biocidal effect, four bacterial test series were performed with Escherichia
coli. The entirety of the tests analyze the plasma inactivation process from
the input parameters to the desired biocidal effect. The discharge current and
time resolved ignition behaviors indicated a simultaneous formation of
filaments at the beginning of the negative half-cycle. The dynamics of the
ozone production showed a saturated exponential growth upon a maximum value of
435 ppm. Additionally, the microbiological test series unveiled differences
between the plasma source concepts. A total reduction rate of Log-4 within a
minute was achievable. An air flow through slits within the plasma sources
destabilized the plasma. Minor changes of the electrode geometry changed all
measured parameters. Hence, to develop a pathogen inactivating plasma source,
these results recommend a comb-shaped electrode design, which is laminated on a
dielectric.
