I am trying to characterise pulsed plasma by Langmuir probe using fixed bias from oscilloscope, but there is one problem.
At the rising and falling edge of discharge voltage there lies a corresponding delay of 100-200 micro seconds in ion saturation part then it starts decaying decaying, which is unusual.
Someone can explain why this is happening?
Can you post a picture of your I-V characteristics here? It would make it much easier to answer your question.
I am attaching ion saturation graph here.
you can see spike at two end of graph that I want to remove from my data.
Still I don't know the reasaon
OK - are these spike reproducible?
If so, do they occure when you switch on/off your plasma?
If also that is the case it might be a pickup signal from the plasma source as switching usually goes hand in hand with some voltage or current peak that might then get caught up by your probe because the probe is also working as some kind of antenna.
yes these spikes are reproducible and it always occurs while switching on/off of plasma.
so can you suggest me some solution to avoid this spike.
I am stuck here.
You can trigger your measurements accordingly, so that it just do not measure the spikes.
Hi....I got the solution
and I am again attaching ion saturation which contains no "Glitch".
The reason for that glitch was improper shielding.
Thanks
the decay of ion saturation current may be due to the collisions of ions with probes causes to heated the tip of probes which cause to increasing its resistance and then the ion current decreases.
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