We were mostly looking at uranium over background daughters.
Just buy a Thorium welding rod (Now forbidden in some countries). You can see everything in there...We use them for calibration! You just take some pieces and get several hundred counts/s.
The church of SM physics
-
‘Peak enhancement’ algorithms have a tendency to turn noise into signals:
I''m not 100% sure but I don't think that the peak shaping and peak enhancement that Wyttenbach mentions is the sort of enhancement discussed in your link. I had a look at the Theremino documentation Wyttenbach mentions and there they say that it is the timecourse of the signal emerging from the NaI sensor that is shaped into a Gaussian or trapezoid before being binned by the multichannel analyzer. Each gamma event evokes a shower of scintillation photons in the detector so I think that this is a move to quickly estimate the time integral of each shower because this should be proportional to the energy of the original gamma ray. Anyway, not really related to peak enhancement in the eventual spectrum (unless there is a separate such algorithm in use)
-
Just buy a Thorium welding rod (Now forbidden in some countries). You can see everything in there...We use them for calibration! You just take some pieces and get several hundred counts/s.
LOL
The 7 channel had a 1 L Crystal.
-
Sorry. Of BGO I think
-
The gamma spec was also calibrated with Cs137, K40, Thorium, Americium. The 'low background' steel box Wyttenbach mentioned is made from 15mm boiler plate and is around 1 ft3 (0.01M3)
-
Most of background is just random noise.
It is? It doesn't appear to be. The 10 minute background you show in Figure 2 seems me to be pretty well characterized. What part of this do you think is random noise?
Based on what I see here, I would expect this background to be pretty much unchanged if you collected it for twice as long or even longer. The random component seems already small after 10 minutes*. Can you exhibit 10 minute background vs a longer-acquisition background so people can see what you mean?
*Note added in edit: I shouldn't have put it this way. I assume that the random component is Poisson distributed and so its variance should equal the mean. Since what are displayed here are time-averaged mean bin counts, what I should have said is that the standard error around these mean counts seems already small after 10 minutes. Thus, the background spectrum seems already well characterized at the 10 minute point.
-
*Note added in edit: I shouldn't have put it this way. I assume that the random component is Poisson distributed and so its variance should equal the mean. Since what are displayed here are time-averaged mean bin counts, what I should have said is that the standard error around these mean counts seems already small after 10 minutes. Thus, the background spectrum seems already well characterized at the 10 minute point.
Yeah - So… as long as the duration of the background reading equals the duration of the test (and they are both suitably lengthy, 10min?) then one can get reasonably accurate results from taking the delta?
-
Yeah - So… as long as the duration of the background reading equals the duration of the test (and they are both suitably lengthy, 10min?) then one can get reasonably accurate results from taking the delta?
The durations don't have to be equal. The signal-to-noise ratio for photon noise (aka Poisson noise or shot noise) is proportional to the square root of the acquisition time (for both background and test). So ... go 4 times longer and the the signal-to-noise ratio improved by 2 times. You just have to go until you are happy with the signal. The background in Figure 2 looks pretty good to me
-
The durations don't have to be equal.
Of course duration must be equal. Else the noise effect flattens tiny background peeks!!
There are two(3) sources of noise:
1) Instrument the bucket assignment is modulo 600 with some adaption to energy. So a line in the middle can end up in two buckets.
2) The same for media interaction that can lead to tiny damping effects.
3) Secondary gammas from Beta +/- electrons or alphas can be damped too, what shifts some peeks.
-
I wonder if Wyttenbach is using "noise" in the same way as I am. The caption for his Figure 2 reads " Fig. 2 shows a typical noisy 10' uni directional background ...". And a little while ago on this thread he said "Most of background is just random noise". But to me, the random noise in Figure 2 looks small in relation to the signal. What I mean by this is that if the background were to be redone I think it would look almost the same. All the mean bin values would be within a percent or so of what we see now. This is because the noise I am thinking of is "photon noise" associated with the random nature of gamma ray production.
Another definition of "noise" is something that interferes with things that the researcher wants to measure. From this perspective, the entire background is "noise". And it is in this sense that the background of Figure 2 could be called "noisy" (as Wyttenbach does). But this is not random noise. It is not stochastic. This "noise" is a signal, a background signal. And, crucially, this signal is not the sort of thing that goes away as you go to longer and longer acquisition times -- instead it just becomes better characterized. This is why it mystifies me when Wyttenbach says that some of the "most active discrete lines" in the background spectrum can't be seen unless you acquire the spectrum for substantially longer than the 10 minutes of Figure 2. Any discrete line rising more than a couple of cps above the continuum part of the background should already be pretty visible after 10 minutes -- at least as judged from Figure 2. But I take it that the "most active discrete lines" Wyttenbach is referring to must be an order of magnitude or more larger than this.
So I don't understand what is going on. I don't understand why some very prominent background lines are not visible in the spectrum of Figure 2. I don't understand why such a line would appear with a longer acquisition. And I don't really understand how Wyttenbach is using the word "noise". Maybe there is a good explanation for all this. I just haven't seen it yet.
-
But this is not random noise. It is not stochastic.
Of course all background contains also non noise signals like 41K and the full Th/U decay line salad as in our case. Others see all Radon decay lines. But every m2 on earths surface is hit by 1 muon/s and these muons trigger myriades of particles and secondary decays and this is the real noisy part. As said +-15% depending in day time as the earth is also a shield for the sun and more active space regions.
-
Of BGO I think
Bi in 1L of BGO could generate some BG?
-
Bi in 1L of BGO could generate some BG?
Bismuth Germanate Oxide. I’m not sure what you mean above.
-
... every m2 on earths surface is hit by 1 muon/s and these muons trigger myriades of particles and secondary decays and this is the real noisy part.
But mostly this is a signal. Part of the background signal. Not random noise. True, there is a random component because you can't predict exactly when the events will happen, but that is why you average the counts over time when taking the spectra. Those averages will become less and less affected by the random component as you take more and more data.
Your Figure 2 shows mean cps in each channel after 10 minutes. Those means estimate the activity of a true signal -- the background signal -- including events generated by muons. During the first 10 seconds of acquisition, those means weren't as reflective of the true signal because of the random nature of photon arrivals (i.e., in some channels not many events had occurred yet just by accident). But after 10 minutes the errors introduced by random sorts of things have evened out and each mean is a better estimate of the real signal. If you want an even better estimate, then take the background for 20 minutes and the standard error around those means will be even smaller. You are calling the signal part "noise". That is fine because in the overall experiment this signal is in your way. It is something you want to ignore so as to focus on the gammas generated by your fuel. But it isn't random noise. It is signal. It is background.
As said +-15% depending in day time as the earth is also a shield for the sun and more active space regions.
One hopes that the background is stable. That would be great. But if the background does fluctuate there could be a serious problem for your analysis because the background-subtraction process used when analyzing your test signals could fail. Any difference between the background you used for subtraction and the true background that was present during the experiment could appear as a false signal that would then go into your analysis system to be interpreted as gamma radiation emanating from your fuel. This is why I have been worried about the similarity between the shape of your background-subtracted spectrum and the background itself. One reason for this similarity could be that your background-subtraction procedure has failed. You need to convince readers that this is not the case because all subsequent results depend on it.
-
That would be great. But if the background does fluctuate there could be a serious problem for your analysis
What kind of serious problem?.Please enlighten me
Do you have software available and have you ever used it?
Do you have expertise in gamma spectrometry data analysis?
Can you reference some of your work?
I’m not sure what you mean above.
:https://www.advatech-uk.co.uk/bgo.html
Bi is intrinsically radioactive..maybe its no big deal
,
207mBi 182(6) μs 21/2+ 208Bi 83 125 207.9797422(25) 3.68(4)×105 y β+ 208Pb (5)+ 208mBi 2.58(4) ms IT 208Bi (10)− 209Bi 83 126 208.9803987(16) 2.01(8)×1019 y α 205Tl 9/2− 1.0000 -
Do you have software available
older PRA software is available here...more hands on than Theremino
and more time intensive
"This adapter can be used with the well known freeware software PRA (We thank Marek Dolleiser for having paved the way for this kind of analysis, its software PRA is a reference for many years and helped a lot) but only with the Theremino_MCA you can do filtering and deleting useful background to get maximum information within a reasonable time.
PRA - Gamma Spectroscopy Software
"
PRA was designed for the purpose of teaching University physics students about spectrometry, so many things that could have been automated have deliberately been left as manual processes.
Students were encouraged to analyse spectra, calculate energies and determine isotopes, rather than using a "no brain required" system that does all the work for them.
Of course when you understand the method you are qualified to move on and use any system.
Steven"
Steven Sesselmann | Sydney | Australia | https://gammaspectacular.com | http://groundpotential.org | https://beejewel.com.au |
-
If random date background spectral readings are tested as though they are experiment spectra, and have another random date background subtracted, and those results run through the line resolution algorithms, how often do false positive lines occur of the type you claim to detect during successful experiments?
Edit: I wouldn’t expect that the results of this are known currently, but it is a solid cross check. I recommend that someone independent runs the analysis or selects the sample data periods if feasible. -
someone independent runs the analysis or selects the sample data periods if feasible.
I forwarded the report to Steve Sesselmann here in Sydney...he may have a few weeks or months to spare for free. not soon though.
External Content www.youtube.comContent embedded from external sources will not be displayed without your consent.Through the activation of external content, you agree that personal data may be transferred to third party platforms. We have provided more information on this in our privacy policy.I doubt whether Irina or Alla are still in the research or gamma business...or whether they are into detailed stats. I think they did some gamma work with tungsten and deuterium back in the day...with love from Russia.
Gamma Emission Evaluation in Tungsten Irradiated By Low Energy Deuterium Ions. 258
-
But if the background does fluctuate there could be a serious problem for your analysis because the background-subtraction process used when analyzing your test signals could fail. Any difference between the background you used for subtraction and the true background that was present during the experiment could appear as a false signal that would then go into your analysis system to be interpreted as gamma radiation emanating from your fuel.
Of course you failed to read/understand the paper. It is written that we did use 2 different backgrounds a lower and a higher one. In fact we compared with the highest signal of both together...
The findings published are breakthrough science! Thus we did it very carefully!
-
Of course you failed to read/understand the paper. It is written that we did use 2 different backgrounds a lower and a higher one. In fact we compared with the highest signal of both together...
I am reading your ResearchGate manuscript and it is true that I am failing to understand some parts. It isn't an easy read! Partly because in some parts you describe some things very briefly, in an opaque manner, and without explanatory figures.
I noticed that you have 2 different sets of background measurements: a "uni directional" one taken somewhere "behind" the experiment, and another one "in view" of the experiment (in the same position as during acquisition of spectra from the active fuel?). The first one has higher average count than the second. But it is unclear what you are doing with these 2 backgrounds.
You say "All results here are double checked against two different types of background to avoid temporary transparency effects with false positive/negative signals." But I am unsure what this means. Are you saying that you used first one background and then the other for background subtraction and got the same results both times? And what are you now saying about "both together"? I don't understand because this is not clearly explained.
Also, talking about things that I read in your manuscript but don't understand, what does this mean .... "Long run backgrounds cannot be use to discriminate lines as possible bursts are hidden." What bursts? Bursts of gamma activity from the active fuel pellets? How would this interfere with a background which should be measured when active fuel is not around at all?
