Re: [Phys-L] geiger counter

[Mark Sylvester <wk76msyl@uwcad.it>]

I don't see mention of my favourite source: filter air through a cotton pad
using a vacuum cleaner for about 5 minutes. The cotton pad becomes a
surprisingly strong source of beta radiation, apparently due to Pb-214 and
Bi-214 from the decay of atmospheric Radon. The ions stick to charged sites
on the cellulose molecules. Both have half lives around 20 minutes so very
nice observations can be made of the double decay, which can be modelled
with a spreadsheet simulation. I have the "Aware Electronics" large
diameter GM tube that was ideal for this. It interfaces to a USB port, but
the counting software does not work with the newer versions of Windows and
internet searches suggest that the firm has gone out of business. Does
anyone have information about this?
Mark Sylvester

On Thu, 9 Mar 2023 at 05:31, bernard cleyet via Phys-l <
phys-l@mail.phys-l.org> wrote:

> ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………...i’ve
> included phys-l so member(s) may correct any error(s)
>
>
> interleaved:
>
> > On Mar 8, 2023, at 13:02, Anthony Lapinski <alapinski@pds.org> wrote:
> >
> > Responding (again) offlist.
> >
> > Still searching for geiger counters. I found some that detect alpha,
> beta, and gamma rays, and some also can detect x-rays. So for my purposes
> (everyday objects - Fiestaware, smoke detectors, lantern mantles, uranium
> glass, radium watches, etc.), are these all alpha emitters? If so, then a
> geiger counter which does not detect alpha rays will not detect anything
> from these items?
>
> U has has a long chain of progeny (formerly, non-PC, daughters).  As a
> result all are emitted. (Alpha Beta and Gamma and XRF (X-ray
> Fluorescences). I suspect no Alphas will be detected as the glaze is not
> pure U.  Well some U will be on the surface.  I’ll check this soonly and
> report back.
>
> Geiger counters do not detect Gammas directly (except possibly v low
> energy ones, e.g.  the 14 keV one from I-57, which excites the Kalpha x-ray
> at ~ 6 keV .  These can be detected directly, I think due to the photo
> effect. The higher energy photons emit electrons from the case.  This, I
> presume, is the reason the shell is steel instead of Al.  This can be
> verified by using a semi-collimated photon beam and compare the counting
> rate through the window and turned Pi/2 through the shell.  (I must do
> this, also). G-M manufacturers also manufacture tubes with metal girdles
> that linearized the gamma sensitivity.
>
> Included here:
>
> https://en.wikipedia.org/wiki/Geiger–Müller_tube <
> https://en.wikipedia.org/wiki/Geiger%E2%80%93M%C3%BCller_tube>
>
> More:
>
> K-40 emits positrons, rarely,  gammas, and betas.  (140 ppm in nature,
> thus we are a radiation source).
> https://en.wikipedia.org/wiki/Potassium-40
> Thorium. also natural (Th-232) has 11/9 progeny It has one branch.  So it
> emits all three.
>
> https://en.wikipedia.org/wiki/Thorium-232
>
> Radium is a “daughter of all three U-235/238 and Th.
> https://en.wikipedia.org/wiki/Uranium-238 and
> https://en.wikipedia.org/wiki/Uranium-235
>
> Americium emits gammas in addition to the useful alphas.
>
> > Also, how useful is an x-ray detector for basic classroom purposes?
> >
> > I do like the EG Geiger kits.  I wish they had a case/housing to protect
> the components.
> >
>
>
> The kit using a large G-M box includes a case.  yes it clicks and flashes.
> Will the case obscure the flash? Wrong drill hole(s).
>
> http://cdn.goldmine-elec.com/datasheet/C8092Measurements.pdf
>
>      http://cdn.goldmine-elec.com/datasheet/C8092V1.pdf.
>
>
> bc
>
>
>
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