Inductively coupled rf sources are important tools in semiconductor plasma processing. In recent years, these tools also have been investigated for medical applications like plasma sterilisation and surface modification of polymers. This is the reason why a double ICP source has been developed. In order to characterize these different plasma sources, Langmuir probe measurements, energy-resolved mass spectrometry, optical emission spectroscopy and plasma modelling have been applied to different ICP sources. For time resolved measurements, Langmuir probe and mass spectrometer were synchronized. Time and position dependent profiles provide a deeper insight into physics of these source and provide additional parameters like puls frequency and duty cycle for adjusting new or improved processes.