Archive for the ‘FAQs’ Category

Use of Concise Notation for Half-life Uncertainties

November 28th, 2018

The use of the concise notation is best demonstrated with an example. Research papers often publish half-lives in so-called ‘non-concise’ form. As an example, the half-life of the alpha emitter Gd-148 has been measured to be T1/2= 70.9 ± 1.0y. When this information is published in, for example, ENSDF, NDS etc. a more concise notation is used as shown in the diagram below for Gd-148 i.e. T1/2(y) = 70.9 10 where it understood that the number in italics is the numerical value of the standard uncertainty referred to the corresponding last digits of the quoted result.
Gd148 Extract from ENSDF for nuclear data on Gd-148.

As another example, the half-life of Po-209 is given in the original scientific paper as as T1/2(y) = (125.2 ± 3.3) a. In Nucleonica’s Nuclide Datasheets, however, the half-life is given as T1/2(y) = 125.2 (33) a. Notice the notation follows that of NIST which is slightly different from the ENSDF above (NIST has the uncertainty in brackets, non-italic e.g. (33); ENSDF has the uncertainty in italic withour brackets e.g. 33). Further examples of uncertainties notations are shown below.
NDS-Uncertainties For further information see the references below.

References
Use of concise notation for data uncertainties
Standard Uncertainty and Relative Standard Uncertainty
ENSDF manuel; Note on uncertainties is on page 104
NDS Notes on page 7

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How to add Nucleonica login to your smartphone/tablet homescreen

November 23rd, 2018

Launch the mobile browser and open the website or web page you want to pin to your home screen. Use https://nucleonica.com/?login to pin the login page for fast access (If you do not see the login page, clear the cache using Ctrl+F5). Tap the menu button and tap Add to homescreen. You’ll be able to enter a name for the shortcut and then Chrome will add it to your home screen.
More information

Mobile-Nuc2On the homescreen shown above, four Nucleonica pages have been added:
1. Nucleonica Login (click on this icon to get to the login page. Click again to enter the portal, assuming username and password have been saved).
2. NucleonicaBlog (click here to go directly to the latest information on the blog)
3. Nucleonica Faqs (Click here to go directly to the Frequently Asked Questions)
4. Nucleonica Wiki (Click here to go directly to the Nucleonica wiki)

See also Nucleonica for Smartphones

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Unidentified peaks in I-125 spectrum

May 30th, 2018

Qu. (from Z. S. JRC Karlsruhe) Using the Gamma Spectrum Generator app in Nucleonica I have created a gamma spectrum for I-125 (shown below). Comparing the results from the Nuclide Datasheets++, I find the three lines at approx. 35, 31, 27 keV (see inset from the Datasheets++). Where do the extra peaks at approx. 21 and 17 keV come from?
UnPeaksAns. (Nucleonica Team)
The additional lines from the I-125 spectrum are X-escape peaks.

Ge emits X-rays at approx. 10 keV (Intensity 48%), 11 keV (intensity 6%), and about 1.2 keV (Intensity 0.5%) so Xesc-peaks can be expected at:
21 keV = 31 keV – 10 keV
20 keV = 31 keV – 11 keV and 21 -1.2

17.6 keV = 27.5 – 10 keV
16.5 keV = 27.5 – 11 keV and 17.6 – 1.2

25.4 keV = 27.5 -1.2 keV
The relative intensities correspond about to the relative Ge X-ray intensities.
More information:
X-Ray Emission Lines
X-ray Escape Peaks

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Feedburner Deactivated

May 3rd, 2018

Because of recent problems, the Feedburner service for managing RSS feeds has been deactivated. The Nucleonica Blog posts are now sent directly to Nucleonica’s Networking page using the WordPress feeds. Users can no longer receive these post feeds via email. However, the most recent feeds are shown directly on the Networking page.

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SSL secure access active again

April 9th, 2018

SSL secure access has been reactivated.
Access to Nucleonica again available now through https://nucleonica.com.

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SSL temporally disabled

March 28th, 2018

SSL temporally disabled

Due to problems with the renewal of the nucleonica.com SSL certificate, the SSL (https) has been temporally disabled.

As soon as the problem has been resolved, the SSL will be reactivated.

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Half-lives of the nuclides Rh-102 and Rh-102m

March 13th, 2018

Qu. (from M. D. KTE Karlsruhe): In using the platform Nucleonica I found some inconsistent data. The half-lives of the nuclides Rh-102 and Rh-102m are not the same in the different specified databases. The half-lives of Rh-102 and Rh-102m seem to be inverted at „JEFF-3.1“ in comparison to „ENDF/B-VII.1“ or „Nubase 2012“. Do you have information which the correct data for these two nuclides are?

Ans. (Nucleonica Team): The most relevant information on the radionuclide Rh-102, 102m half-lives can be found in the paper: M. Shibata et al. Applied Radiation and Isotopes Volume 49, Issue 12, 1 December 1998, Pages 1481-1487
Beta-decay half-lives and level ordering of Rh-102m,g. link
Citation from the abstract of this paper: Beta-decay half-lives of the ground state and an isomer of Rh-102 have been determined 207.3(17) d and 3.742(10) y, respectively, by γ-ray decay curves following each β-decay. It has been found that a state (2−) which has a shorter half-life (207.3 d) is the ground state from the result that the half-life of the 41.9 keV isomeric γ-transition was equal to 3.742 y. It has also been confirmed that the 41.9 keV transition is certainly an isomeric transition with X–γ coincidence measurement.
——
Rh-102The data for Rh-102 in the new 10th Edition of the Karlsruhe Nuclide Chart, 2018.
The data in Karlsruhe Nuclide Chart 10th edition, recent NUBASE file and ENSDF are based on this research. In JEFF3.1 the ground and metastable states were allocated incorrectly. We recommend to use the latest information based on the above mentioned research and summarised in the Karlsruhe Nuclide Chart as shown in the figure.

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Radiological Converter vs. Mass Activity Converter++?

November 11th, 2017

(Qu.) What are the main differences between the Radiological Converter and the Mass Activity Converter++?
(Ans. Nucleonica Team) The Radiological Converter is a further development of the Mass Activity Converter++ with the following additional features:
* The list of conversion quantities now includes a) Air Kerma Rates b) Exposure Rates and c) Ambient Dose Equivalent Rates H*(10) for approximately 1500 gamma and x-ray emitting radionuclides (depending on the database used).
* The threshold energy used in the calculations for dose quantities can be set by the user to investigate the effect of low energy photons on the dose calculations.
* Account is taken of short-lived daughter nuclides when a parent nuclide is selected.
* The underlying dataset used in the calculations can be selected from a list of international nuclear datafiles (JEFF3.1, ENDF/B-VII.1, 8th TORI)

The Radiological Converter thereby provides the internationally accepted ambient dose H*(10) and is suitable for declarations of radioactive packages.

More info…
Radiological Converter wiki page

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Decay engine: daughters present at time t=0?

November 2nd, 2017

(Qu.) If we take Ra-224 as an example I can set the starting quantity (N0) of Ra-224. The other nuclides in the chain start with N0 = 0. But If I also have an amount of say Pb-212 at t= 0, i.e. N0 is not equal to 0 at t= 0. Is it possible to do this in the Decay Engine?
(Ans. Nucleonica Team) This is straightforward in Nucleonica. You first create a nuclide mixture with say Ra224 (1 MBq) and Pb-212(1 MBq). Then save with the name e.g. Ra-Pb mix.
You then go back into the Decay Engine and click on the Mixture Selection. You should then see the Ra-Pb mix in the drop-down menu. It may be necessary to refresh the page so this the new mixture is loaded. Then you can redo the decay calculation with the mixture. The results are shown below.
RA-PB

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Problem with the decay chain of Pu-244 and the JEFF database

July 25th, 2017

Qu.(from M.R. KTE Karlsruhe): We encountered a problem while reproducing the decay chain of Pu-244.
The first decay is an α-decay to U-240 followed by a β-decay to Np-240. The question is if U-240 decays to the metastable or directly to the ground state of Np-240. In the universal nuclide chart application in Nucleonica it shows a difference between the JEFF (Np-240) and ENDF (Np-240m) databases.
When using the Decay Engine++ application only the Np240 ground state is shown. The (more like a juristical) problem is that our regulations only include the metastable state.
Do you have additional information about the decay of U-240? Which one is the physical correct daughter?

Ans.(Nucleonica Team): Indeed there is an error in the JEFF3.1 database. You can also see this clearly in the KNCO application where you see that U-240 decays to Np-240m only. In view of this, we have changed the data in JEFF3.1 for U-240 – allowing only the decay to Np-240m. This you can see in the Nuclide Datasheets.
If you now redo the decay calculation for Pu-244, you will see the Np240m is much more important than Np240.
Thanks again for pointing this out and hopefully it did not cause to much inconvenience. It just shows once again how important it is to have a number of databases for comparison purposes.

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