Gamma Spectrometry Forum

Hi David, No, I am not interested in dating. That would be difficult (at least with my equipment), since most of the gamma spectrum of old uranium rocks is Ra-226 (from U-235). U-238 is practically invisible, except in rocks that have the Ra-226 leached. What I would like to know is if a mineral is ...

Hi David, Thank you for the reply and advice. I was thinking I could avoid worrying about efficiency issues by constraining the problem as follows: 1. Only estimate U:Th ratios on the basis of 238:(295+352)keV emissions 2. Small samples (avoid self-shielding and geometry issues) 3. Old samples (>10^...

PRA seems to have a time lag in some measurements. 10 real-time hours have passed but it says that it has measured for only 2.
Any idea why this happens?

OK, here is Am-241 with the expanded range.

And here is the scattering off a piece of polycrystalline Si after background subtraction. Basically the same FWHM as the source.

Hi Luuk,

The crystal is 1x1x3cm.
This is the Am-241 spectrum.


Note that the previous XRF/scattering data as only at 10k pulses.

Boris

In measurement mode it subtracts, but once I save, the background comes back. Is this the intended mode of operation?

Next, I got excited about checking this on some rocks. First one shows some Er peaks, OK, possible since it was from some magnetite with fergusonite (YNbO3) with known 3% erbium content. So, I check another - roughly the same effect. I test a fossil (!) - same thing. Luckily, some of that rusty phys...

Hello, I have been trying to squeeze the most out of my beginner CsI(Tl) gamma spectrometer and looking for things to do with old smoke detectors. I was too impatient to design a proper setup, so I set up a piece of polystyrene foam with a hole at 45 degrees away from the spectrometer and a small ar...

Hi Steven, I started using InterSpec. It is indeed very good. The peak fitting is a bit shaky, especially on close or overlapping peaks. I also wish it had a way to save a file with all the analysis. But the isotope data in there is very useful and it is generally a great program. Thanks for the adv...