Hi Jason,
Did you look at Geiger counter? There are many designs available online.
You could modify the firmware to provide integration if the count over
time, and whatever else info you want.

Just a thought,
Jean-Paul
N1JPL

On Sun, Sep 30, 2018, 11:41 AM Jason White <
whitewaterssoftwareinfo@gmail.com> wrote:

> Hello everyone,
>
> Recently I learned my neighbor has high levels of Radon in their basement
> (they installed a mitigation system). Naturally, I was curious as to the
> level in my own basement and purchased an electronic radon meter [1] from
> the local hardware store [2]. Testing shows that my basement has a
> concentration of roughly 20pC/L. (I am currently working on reducing the
> level)
>
> One inconvenient aspect of the electronic meter it does not provide an
> instantaneous reading. It takes 48 hours to obtain the first reading. And
> all subsequent readings are provided by the meter as a long term average.
> That got my thinking: can I build my own Radon (alpha particle) meter?
>
> As I understand it a electronic Radon sensor is essentially a large spark
> gap. A potential is applied across the gap and when Radon gas decays it
> emits alpha particles which causes the air in the gap to ionize - causing=
 a
> momentary spark across the gap. With this type of sensor I would assume t=
he
> level of radon gas is proportional to the number of sparks across the gap
> per second.
>
> I would like to learn: what it would take to design my own radon gas mete=
r?
> (For fun, not commercially) Any advice or links to resources (formulas,
> charts) would be greatly appreciated.
>
> I have not torn apart/reverse engineered my meter yet because I do not wa=
nt
> to alter the calibration. The documentation states that the sensor voltag=
e
> in my meter is 250 volts (DC?). I would assume higher voltages and larger
> spark gap areas would yield higher sensitivity. I would have to wonder if
> dust and other contaminants would be an issue for this type of detector?
>
> [1] SafetySiren Pro Series 3 Radon Gas Detector, Claims initial accuracy =
of
> 20% or +/-1pC/L (whichever is greater).
> [2] Home Depot
>
> --
> Jason White
> --
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