Uranium glaze ceramic - hpge spectrum

[sgt_bear]

Hi folks,

After initial tests with my hpge to assure working state, i've decided to run a ten hour background run. The next sample i analyzed was three pieces of ceramic with glaze that contained uranium. I've let the pieces for around 10 hours on the unshielded hpge detector.
Here you can see the low end of the spectrum containing the relevant peaks for the U-235, Th-234 and some X-ray peaks from U and Pb. The background is referenced in the blue line

Please notice that everything in the spectrum <40keV is just noise, since this type of HPGE is "blind" under 40keV

Low Energy.png

The peaks for U-235 are left-to-right:

143.76 keV - 10.90%
163.35 keV - 5.08%
185.71 keV - 57.2%
202.11 keV - 1.08%
205.30 keV - 5.01%

What do you think of this spectrum?

An interesting discovery was made:

At around 1000 to 1002kev is a large unknown peak, since the background spectra does not have any indication of this peak, it must come from the glazed ceramic. In addition, i did a test with uranium doped glass, and its shows the same peak.
Does anyone have an idea what could be the cause of this? What isotope it could be?

Mystery peak.png

[Sesselmann]

Jonathan,

Thanks for sharing, you are making everyone envious :)

Not sure how linear your spectrum is, but is it possible that your mystery peak is just a sum peak at 1022?

[GigaBecquerel]

Very nice spectrum, I love it!
Welcome to the world of high rez gammaspec ;-)
That peak is the 1000.99 keV gamma from Pa234m, which has a branching radio of ~1%.
Now that you have a "real" spectrometer I highly recommend you to give Interspec a try, that easily identifies and lables peaks.

Lukas

[sgt_bear]

Thank you Lukas, yes i've reasearched about Pa234m and i guess you are right!

I've taken a look into Interspec - its wonderful!