  Atmospheric pressure plasmas have been ground-breaking for plasma science and
technologies, due to their significant application potential in many fields,
including medicinal, biological, and environmental applications. This is
predominantly due to their efficient production and delivery of chemically
reactive species under ambient conditions. One of the challenges in progressing
the field is comparing plasma sources and results across the community and the
literature. To address this a reference plasma source was established during
the `Biomedical Applications of Atmospheric Pressure Plasmas' EU COST Action
MP1101. It is crucial that reference sources are reproducible. Here, we present
the reproducibility and variance across multiple sources through examining
various characteristics, including: absolute atomic oxygen densities, absolute
ozone densities, electrical characteristics, optical emission spectroscopy,
temperature measurements, and bactericidal activity. The measurements
demonstrate that the tested COST jets are reproducible, within the standard
deviation, for each measurement.

Plasma Physics