How Do You Calculate Holding Current for a Spark?

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To calculate the holding current for maintaining a spark, factors such as gas mixture, pressure, and temperature are critical. The discussion centers around resistive plate chambers (RPCs) and the need for a formula that incorporates these variables to estimate the holding current. The user is specifically interested in working with a Ne + Isobutane gas mixture at atmospheric pressure and room temperature. Additionally, references to literature on the topic, including a link to a Wikipedia article on Geiger-Müller tubes, are sought for further insights. Understanding the relationship between resistor size and discharge maintenance is also highlighted as a key consideration in the design.
a2009
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Hi All,

I'm designing an experiment and want to estimate the holding current (minimal current to maintain a spark) for my setup.

Does anyone know how to calculate the holding current? I imagine it should depend on gas mixture, pressure, temperature.

A reference to a book/article discussing this would also be very welcome.

Thanks a bunch!

Adam
 
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Let's see how good my mind-reading skills are today. Are you wanting to maintain an electric arc in a pressurised inert gas? Which gas? What are the electrodes? Is this at high pressure or low pressure (cf. atmospheric).

In any case, I doubt that I can assist. But I'd say no one will be able to if you don't provide more details. :smile:
 
Thanks for showing me the question wasn't clear.

I'm looking into resistive plate chambers, and am trying to get a feeling for how to design the resistivity of the plate.

In RPCs, like in Geiger counters, the detectors undergoes a discharge whenever a charged particle traverses the active area (loosely speaking).

I'm thinking of the discharge as the shorting of a capacitor. So assuming the capacitor is shorted, what resistor do you need to put after in order to have the spark die out. When looking through literature I came across the term "holding current" as being this value.

So to rephrase, I'm looking for some formula, that would allow me to estimate the holding current (to make sure I'm below it). Because I'm also deciding on the geometry I would need something in which I can plug in geometry, gas type, pressure, temperature and see what I get.

As a baseline I would like to work in something like Ne + Isobutane 95/5 at atmospheric and room temp. But this can change totally.

Mostly I'm looking for a reference describing what determines the holding current of an arc.
 
see here...I did not read it all,,,maybe some insights :

http://en.wikipedia.org/wiki/Geiger–Müller_tube

The resistor likely allows a voltage to be maintained so that discharge will occur when a particle is detected...when the particle passes and ionization of the gas completes, the current stops...that doesn't seem to depend on the resistor size.
 
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