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On 2/8/20 4:49 PM, David Eckhardt wrote:
> Are you still able to get a meaningful spectrum from the trinitite
> _with amateur probes_?? It's over 70 years old.

I think it depends on what you mean by "meaningful".? I have not tried
XRF of Trinitite, but I have done some Gamma spec on my specimens.? I
have used a Scionix 2x2NaI(Tl) probe with the UCS-20 MCA as well as a
22mmx25mm CsI(Tl) probe with Theremino adapter and software.

I almost hate to attach this example because it is very sloppy and not
properly calibrated.? This scan of a small 4.3 gram specimen was done in
open air; no lead castle, no supplemental shielding and no background
removal.? This was a 7 hour scan and room temperature went wherever it
wanted to go.? I have made no effort to identify any of the isotopes; it
was nothing more than a preliminary scan of a new-to-me specimen just to
see what I could see - ? Just a quick'n'dirty preliminary look.? It was
done with my Scionix 2x2 NaI(Tl) probe and the UCS-20 MCA.? I saved the
UCS-20 data file and plotted it with GnuPlot so I could play with
intervals and data ranges.

But even with with that said, I think it is apparent a careful setup,
properly calibrated and attention paid to temperature drift would reveal
the general nature of what radioactivity remains (within the limits of a
NaI(Tl) probe).? For sure the Cs137 is easy to find, as is the Am241.?
Other stuff is there, too, but accurate calibration is missing. For
reference, the Scionix 2x2 NaI(Tl) probe I obtained from Luuk yields an
honest 6.8% resolution at 662 keV, and that is about the best I will be
doing any time soon.

I have been intending to take a more serious look at my Trinitite
specimens but right now my "rad lab" is in a serious state of disarray.?
I need to get it cleaned up, organized and shielding back in place
before I can try to do much more.? I have been getting serious Probe
Envy looking at Charles' and Geo's results but truthfully, right now I
can't even effectively use what I already have.

AnotherWally


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AnotherWally
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