Gamma Spectrometry Forum

Hello there!

I threw together a small spark counter, because I always wanted to make one.
It's all contained in a small box, with an EMCO F60 supplying the voltage, a small step down delivering 0-15 V for it, and a fan to keep it all cool.
With the right tools on hand you can build a spark counter in a day or two, and I highly recommend you do so!
These detectors are quite fun as they display a few key properties of radiation, mainly the spacial distribution, but also dE/dx of various particles.
By setting the detector bias you can control a minimum ionisation density required to cause a spark. At its highest setting of 6 or so kV my detector even reacts slightly to betas, and at around half that you can set a point where it counts the high energy deposition in a bragg peak, but not to the alphas when they still have multiple MeV of energy!
Here's a small video of the thing in action, with it biased to show the bragg peak first, then to show ~all alphas.
https://www.youtube.com/watch?v=_ASJQCnctPA

Lukas

Lucas,

Thanks for posting, very cool project and nice build.

I wonder if one could build a multi layered cube one with alternating ground and HV grids for detecting muons, might even be possible to see the direction of the muons.

Hmm 🤔

Steven

I doubt it would react to muons, as they have a rather low dE/dx in air.
Maybe, with the right gas it would work?
If you can get some high pressure xenon, and the voltage to go with to get close to a spark...

Very similar detectors are however used to measure the energy of particle beams from accelerators, especially for protons and heavier.
Layer some alternating HV and ground metal plates (usually Aluminium or Iron, depending on your needs) and see where the beam causes sparks, most importantly where it stops causing sparks.
The rest is just using Bethe-Bloch to determine the initial energy of the beam entering your detector!

This is a fantastic post and I enjoyed the video earlier today. (subscribed to your channel) At the risk of asking the following question (on this forum that will make me look stupid instead of YouTube), "What is the source you're using?" (The black cylinder used to generate the alpha particles - I am completely unfamiliar with the device.)

Thanks!
The source is just a few kBq of Am-241, nothing special.
It's a plastic "Pen" with the source itself glued(?) in the end, just for convenient handling.