Search found 12 matches

by bstefanov
11 Aug 2021, 09:45
Forum: Introductions >> Start Here !
Topic: Greetings from Pennsylvania!
Replies: 10
Views: 566

Re: Greetings from Pennsylvania!

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 ...
by bstefanov
11 Aug 2021, 03:20
Forum: Introductions >> Start Here !
Topic: Greetings from Pennsylvania!
Replies: 10
Views: 566

Re: Greetings from Pennsylvania!

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^...
by bstefanov
04 Aug 2021, 23:07
Forum: Software
Topic: PRA time lag
Replies: 1
Views: 166

PRA time lag

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?
by bstefanov
01 Aug 2021, 22:44
Forum: Spectrum
Topic: XRF on a gamma spectrometer!
Replies: 13
Views: 744

Re: XRF on a gamma spectrometer!

OK, here is Am-241 with the expanded range.
Am241_ext.png
Am241_ext.png (82.93 KiB) Viewed 464 times
by bstefanov
01 Aug 2021, 00:55
Forum: Spectrum
Topic: XRF on a gamma spectrometer!
Replies: 13
Views: 744

Re: XRF on a gamma spectrometer!

And here is the scattering off a piece of polycrystalline Si after background subtraction. Basically the same FWHM as the source.
Si_IXS.png
Si_IXS.png (58.74 KiB) Viewed 484 times
by bstefanov
31 Jul 2021, 23:39
Forum: Spectrum
Topic: XRF on a gamma spectrometer!
Replies: 13
Views: 744

Re: XRF on a gamma spectrometer!

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
Am241.png
Am241.png (68.48 KiB) Viewed 486 times
by bstefanov
31 Jul 2021, 10:47
Forum: Software
Topic: PRA background subtraction question
Replies: 0
Views: 155

PRA background subtraction question

In measurement mode it subtracts, but once I save, the background comes back. Is this the intended mode of operation?
by bstefanov
31 Jul 2021, 10:09
Forum: Spectrum
Topic: XRF on a gamma spectrometer!
Replies: 13
Views: 744

Re: XRF on a gamma spectrometer!

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...
by bstefanov
30 Jul 2021, 11:40
Forum: Spectrum
Topic: XRF on a gamma spectrometer!
Replies: 13
Views: 744

XRF on a gamma spectrometer!

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...
by bstefanov
28 Jul 2021, 22:06
Forum: Introductions >> Start Here !
Topic: Greetings from Pennsylvania!
Replies: 10
Views: 566

Re: Greetings from Pennsylvania!

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...