

Analyzing Radioactive Glass from the Trinity Test - blueintegral
http://www.hscott.net/analyzing-trinitite-a-radioactive-piece-of-nuclear-history/

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spikels
The Trinity site is open twice a year to visitors. When I went 10 years ago
there were still bits of the blueish-green glass mixed in with the grass and
sandy soil. A small section was preserved and coverered with a low windowed
box. The ground inside was entirely covered with the strange material.

[http://www.wsmr.army.mil/PAO/Trinity/Pages/HowtoGetThereDire...](http://www.wsmr.army.mil/PAO/Trinity/Pages/HowtoGetThereDirectionstothesiteforthebiannualopenhouses.aspx)

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bigiain
I tried to do this tour about 10 years back - be aware that there are some
quite u expected requirements for non US nationals wanting to do the tour. (or
at least there were back around 2000/2001)

Still disappointed I didn't manage to organize that…

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carlob
As an undergrad at Georgia Tech you should know that if one of my professors
caught me writing some significant digit nonsense like 1.0272303 ± 1.031768
Bq/kg I would not have gotten a degree.

1.0272303 ± 1.031768 Bq/kg or rather 1.0 ± 1.0 Bq/kg means that your
experimental error is so large that your result is compatible with both 0 and
2 Bq/Kg. What's the point of adding all those significant digits if you're
telling us that your result is imprecise, or rather that your experiment can't
effectively tell if there is any activity from Cs-60.

(edit: I wasn't an undergrad at GT)

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blueintegral
That data came from the HPGe, which really does have that precision. I know it
seems like the accuracy is bad since, like you said, it could be either 0 or 2
Bq/kg. However, a Bq/kg is REALLY tiny and that accuracy (which is
proportional to the length of the experiment) is good enough for this
analysis. So the precision is fixed based on the HPGe and the accuracy
increases with the length of time the HPGe took measurements.

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carlob
My point stands: just write 1.0±1.0. If 1 Bq/Kg is small then giving a
precision of 0.1 nBq/Kg is just plain insane.

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blueintegral
You're right, I'll correct it.

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carlob
That's great! I see you're not a physics major, so I apologize if I came out
as aggressive.

In general you want to keep 1 or 2 digits in the s.d. and align the precision
of the mean accordingly.

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jlgreco
Both of the videos at the end of the article are absolutely fascinating (as is
the rest of the article, but I almost skipped the videos; I'm glad I didn't).

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whyenot
The first video is amazing. The structure to the explosion is so beautiful,
but at the same time, I feel like I'm looking at the face of death.

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bigiain
I actually stopped watching git 10 seconds or so in, assuming the whole thing
was just going to be Ken Burns-ed stills of photos I'd already seen. Thanks
for making me go back and watch it all…

I'll also drop in a recommendation for the boom "100 Suns" for anybody who
finds pics like that beautiful...

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lutusp
A Quote: "Kenneth Bainbridge, director of the Manhattan Project, was not
amused with Fermi scaring all the guards."

Correction. Leslie R. Groves, Jr. was director of the Manhattan Project.

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blueintegral
Thanks, fixed.

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raverbashing
Wow, amazing

So I suppose what points this to being Trinity is the ratios, since the values
are very off from the Trinity data in the tables (because of decay)

