Nucleonica’s GSG & GSGPro: limitation of the number of mixture components

June 16th, 2022
by Joseph Magill

Every nuclide mixture, regardless of the number of components, is now accepted by the applications GSG and GSGPro.
When the number of components exceeds the limit of currently 30 nuclides, the application selects the top 30 strongest gamma emitters from the nuclide inventory to compute the spectrum, no matter if the inventory is the originally submitted mixture, or the result of an internal decay calculation of the application.
The nuclides are selected based on the emitted gamma energy given by:
SumEEP = Σi ( Ei · EPi )
where Ei is the energy of the photon i emitted with the probability EPi during a decay reaction. The sum is built over all photons (gamma, x or annihilation) emitted by the nuclide.
This emitted photon energy (per decay) is then multiplied by the activity of the nuclide if decay is not taken into account otherwise by the number of decays of that nuclide during the measurement time.

The advantages of the new approach are multiple and important for the user:
* The same mixture can be used in different applications, regardless of the maximum supported number of components which may be 30 for the GSG/GSGPro, 400 for the BetaDoseRate, or unlimited as for the most of the applications.
* The user has no longer to delete components of a mixture which may be time consuming, and it is not really easy to select the right nuclides.
* The number of mixtures can be reduced
* When the maximum number of nuclides changes or when another approach is used to reduce the computation time the user has nothing to do but benefits directly from the improvement.

* One may also consider the full set of emitted photons and then select the strongest lines independently from the emitting parent and their total number.
* In the Options tab, you can change (Administrators only) the maximum number of nuclides taken into account and compare the accuracy of the resulting spectra as well as the consumed CPU time.

See the related post
Gamma Spectrum Generator for large nuclide inventories

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Nucleonica online training course for UM/LUBW, Video Conference 2022

April 23rd, 2022
by Joseph Magill

Nucleonica Training Course, 20-21 April 2022: Introduction to Nucleonica:
Core Applications and Tools with Exercises

This 2-day training course for
UM (Ministerium für Umwelt, Klima und Energiewirtschaft) /
LUBW (Landesanstalt für Umwelt, Messungen und Naturschutz Baden-Württemberg)
was arranged as a video conference on the 20-21 April 2022. In total 10 staff members from the UM/LUBW and 2 staff members from Nucleonica took part. The course was centred around formal presentations of Nucleonica applications (Decay Engine, Dosimetry & Shielding, Gamma Spectrum Generator, Cambio, and WESPA) together with a case study.
The entire course materials were presented online using the Training Courses app on the Nucleonica website.
Previous Nucleonica training courses.

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New 11th Edition (2022) of the Karlsruhe Nuclide Chart

March 8th, 2022
by Joseph Magill

The 11th Edition 2022 of the “Karlsruher Nuklidkarte” contains new and updated radioactive decay and thermal neutron cross sections data on 1035 nuclides (82 new nuclides) not found in the previous (2018) edition. In total, nuclear data on 4122 experimentally observed ground states and isomers are presented.KNCO11 All thermal fission chain yield data for 235U and 239Pu (with 16 new mass chains) has been updated using the latest values from JEFF3.3 radioactive decay data file from 2018. The thermal neutron cross sections data in nuclide boxes has been also actualized based on the sixth edition of the Atlas of Neutron Resonances (Volume 1-2, author: S.F. Mughabghab, published by Elsevier in 2018).
Most recent values of the atomic weights, isotopic abundances and cross sections are included together with the thermal fission yields for both 235U and 239Pu. For thirteen elements, a range of atomic weights is given to reflect the isotopic variability in natural materials. The accompanying booklet again contains the multi-lingual “Explanation of the Chart of the Nuclides” in English, German, French and Spanish, updated to reflect changes in the Chart. The Reduced Decay Schemes section initiated in previous editions, and used to describe in detail how the nuclide box contents should be interpreted with reference to the nuclide decay schemes, has been considerably expanded.
This new 11th Edition of the Karlsruhe Nuclide Chart is the result of a collaboration between Zsolt Sóti from the EC’s Joint Research Centre and Joseph Magill and Raymond Dreher from the Nucleonica team. The online version of the Karlsruhe Nuclide Chart is available through the Nucleonica nuclear science portal (

More info…
Online shop
Karlsruhe Nuclide Chart, 11th Edition 2022

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Nucleonica Chat

February 14th, 2022
by Joseph Magill

Nucleonica Chat is a communication software tool developed by the Nucleonica Team to provide easy and spontaneous communication between members of the Nucleonica community (either online or offline) while using the Nucleonica apps. Users may exchange results of calculations, their experience with applications and so on through short messages reinforced by emojis or send files up to a length of 2 MB while working with Nucleonica.
The recipients can be selected from a drop down list of the online users, or from a user selection tool.
Chat posts can also be sent directly to the administrators (for questions, report bugs etc.). In summary, users can send message to:
– all online users (from the users online listed in the drop-down menu)
– all online colleagues (all users from the same organisation)
– offline users (using the Search User button)
– administrators (using the entry in the drop-down menu)
ChatUsers can also directly reply to a user message by clicking on the “From User to me” in the main Chat message window. Files (mixtures, gamma spectra, etc.) can be selected and conveniently uploaded to the selected user.
The chat area presents in chronological order a maximum of 50 messages from the past 100 days, depending on which limit is reached first.

Nucleonica Chat

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Nuclear Security training course for BfS, Video Conference 2021

October 5th, 2021
by Joseph Magill

Nucleonica Training Course on Nuclear Security, 28-29 September 2021
This 1-day training course (format two morning sessions) for BfS staff (Bundesamt für Strahlenschutz BfS) was arranged as a video conference on the 28-29 September 2021. In total 10 staff members from the BfS and 2 staff members from Nucleonica took part.
The course was centred around formal presentations of Nucleonica applications (Decay Engine, Dosimetry & Shielding, Gamma Spectrum Generator, Cambio, and WESPA) together with cases studies concerning medical nuclides ((Sm-153/Eu-152, (I-131/Xe-131m).
The entire course materials were presented online using the recently developed Training Courses app on the Nucleonica website.
Previous Nucleonica training courses.

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Is there an “App” for Nucleonica?

October 5th, 2021
by Joseph Magill

(Qu.) Is it possible to have Nucleonica as an App similar to other apps on mobile devices?

(Ans.)“Real” apps run inside the mobile device. As Nucleonica is a web application that needs a web server, this is not possible.
Some “fake” mobile apps are actually only disguised web browser windows that call web applications. That means they cannot be used if the user has no Internet connection. This might be possible to achieve with Nucleonica but not all pages are optimized to be used on mobile devices yet.

And then there are responsive web apps (like KNCLight) that are a mix of these two (actually a web site running on a web server, but It is possible to install them on the device). But in order to turn Nucleonica into one of these, we would have to create new versions of all the pages first (or create a responsive web app that only contains the pages that have already been recreated). These new versions of the pages have to get all information using AJAX calls (instead of getting everything directly in the HTTP GET as it is the case now).

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JEFF-3.3 (2017) decay data now available in Nucleonica

July 12th, 2021
by Joseph Magill

On November 20, 2017, the JEFF-3.3 datafile was released by the NEA.
The JEFF-3.3 (2017) decay data sublibrary is now available in Nucleonica in addition to the previously used decay data libraries JEFF3.1, EBDF/B-VII.1, and ENDF/B-VIII. It is now possible to compare and contrast the main European (JEFF-3.1, JEFF-3.3) and American (ENDF/BVII.1, ENDF/B-VIII.0) data libraries for differences in half-lives, branching ratios, energies and emission probabilities of the emitted radiations, fission yields, etc. using Nucleonica’s user friendly tools. This data comparison can be accessed through the Options tab of the Nuclide Datasheets++ application.

Reference: JEFF-3.3

Posted in Karlsruhe Nuclide Chart, Nucleonica | Comments

Gamma Spectrum Generator – spectrum cut-off at 2500 keV?

March 31st, 2021
by Joseph Magill

Qu.) JTE, BfS, Berlin
Dear Nucleonica Team,
I created a mixture of U-233 and U-232 and tried to obtain the gamma spectra using the Gamma Spectrum Generator.
I noticed that the spectrum was cut off at 2500 keV. Is this a build-in restriction? I am interested in the U-232 daughters Tl-208 which has a peak at 2600 keV.

(Ans. Nucleonica Team)
The cutoff at 2500 keV is due to the choice of the configuration. You probably have used the HPGE with rel. eff. 50% (this is the default).
To increase the range you need to go into the drop down menu for the Current configuration. Then choose Edit from the list of options. Then check the box “Show more settings”.
There you will see that the Channel to energy conversion factor is 0.3 keV per channel. You can change this to 0.35 or some other number to increase the range.
Then return the calculation and you’ll see the 2500 keV peak (see the image below).
This configuration can be saved under a new name if you intend to do more calculations.Tl208at2600keV

Hope this helps

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Possible issue(s) with “inclusion of short-lived daughter radionuclides”

February 23rd, 2021
by Joseph Magill

Qu.) TvD, RIVM, Netherlands
Dear Nucleonica Team,
We are using Nucleonica and we have a question about the following App: Photon Dose Rate Constants++. This app offers the option to include short-lived daughter nuclides.
For Th-232, we get the following results:
Th-232 daughtersThis result occurs for the following two Data sets: 8th ToRI and the JEFF-3.1 (other data sets do not contain short-lived daughters). What is extremely puzzling is the BR product of 2.780E-12 for daughter products Tl-208, Hg-206 and Tl-206. If we look in the help section of this specific app, the following is mentioned under the inclusion of short-lived daughters:
For the calculation of the dose rate constants, some nuclides are considered to be in equilibrium with daughter products. This is the case when a single radioactive decay chain in which radionuclides are present in their naturally occurring proportions, and in which no daughter nuclide has a half-life either longer than 10 days or longer than that of the parent nuclide, shall be considered as a single radionuclide. Such nuclides are denoted with an asterisk in the Nuclide Summary tab e.g. Cs-137*.
In the case of radioactive decay chains in which any daughter nuclide has a half-life either longer than 10 days or greater than that of the parent nuclide, the parent and such daughter nuclides shall be considered as mixtures of different nuclides.

Our issues/questions are as follows:
If the chain is assumed to be in secular equilibrium, the BR product for Tl-208 (we assume this stands for the product of branching ratios, i.e., the compound branching ratio) should actually amount to 0.36, or better: 0.3593.
Why are other gamma-emitting nuclides missing, such as: Ra-228 (it has a half life of 5.75 y, but it should be taken into account as well due to the “either-or” formulation above), Ac-228, Th-228, Ra-224, Rn-220, Po-216, Pb-212, and Bi-212?
These are all preceding daughters (with photon emissions) in equilibrium as well.
Under the same description for included daughters (see above, highlighted text in italics), why does U-238 not have any short-lived daughters? All nuclides could be included as no other daughters have a half life larger than that of the head-of-chain parent radionuclide U-238. Anyhow, I would at least expect the ‘actual’ short-lived nuclides to be included: Th-234 and Pa-234 and Pa-234m.
What are Hg-206 and Tl-206 doing in this chain?

(Ans. Nucleonica Team)
We have now looked into your question in more detail.
Let’ start with …
Issue 4: Where does Hg-206 and Tl206 come from?
Hg206 and Tl206 come from cluster emission (CE) of the parent Th232. This is a very rare decay mode. They are included in the calculation for completeness although they have no effect on the results. If you look into the Datasheets (JEFF-3.1) for Th-232 you will see the cluster emission involves the emission of the nuclei Hg-206 and Hg-208. The nuclide Tl-208 arises through the decay of the cluster emitted Hg-208. (The Tl-208 is somewhat confusing since it arises both through cluster emission CE and from the Po-212 in the Th-232 decay chain. So the three nuclides shown in your table 1, Tl-208, Hg-206 and Tl206, all arise from CE and as such are not important.
Th-232 CE

Regarding the rules in italics…
– Th-232 (alpha) Ra-228: T/2(Ra-228) = 5.75 y > 10 d: not a short lived nuclide and thus no further short nuclides

– Th-232 (2ß) U-232: T/2(U-232) = 69.8 y > 10 d: not a short lived nuclide and thus no further short nuclides

– Th-232 (Ne-26) Hg-206: T/2(Hg-206) = 8.15 min < 10 d < T/2(Th-232) = 1.405e10 y: Hg-206 is a short lived nuclide,

Hg-206 (ß-) Tl-206: T/2(Tl-206) = 4.202 min < 10 d < T/2(Hg-206): Tl-206 is a short lived nuclide

Tl-206 (ß-) Pb-206 stable

– Th-232 (Ne-24) Hg-208: T/2(Hg-208) = 42 min < 10 d < T/2(Th-232): Hg-208 is a short lived nuclide, but has no radiations in JEFF-3.1;

Hg-208 (ß-) Tl-208: T/2(Tl-208) = 3.053 min < 10 d < T/2(Th-232): Tl-208 is a short lived nuclide

Tl-208 (ß-) Pb-208 stable

Issue-1: Here it is sufficient to say that the Th-232 is NOT in secular equilibrium with the (normal) daughters, only the CE daughters.

Issue-2: I think there is a misunderstanding of the rule in italics here. Ra-228 has a half-life of 5.75y and as such >10 days. So it should not be included in the calculation.

Additionally the italics text is not “either or”. The half-life must be less than 10 days AND less than the half-life of the parent nuclide. (this is the IAEA rule). In other words…In fact one follows the decay chains only as long as daughter nuclides having a half-life shorter than 10 days and shorter than that of the parent nuclide are found.

Issue-3: U-238 : the first daughter is Th-234 with a half-life 24.09 days.(i.e >10days). For this reason th228 and all daughters are not included.

I hope this manages to answer the questions you raise.

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Updated activity limits A1, A2 from IAEA SSR-6 ( Rev.1) 2018

February 18th, 2021
by Joseph Magill

The latest values of the activity limits (A1, A2,…) have been updated in Nucleonica based on the Regulations for the Safe Transport of Radioactive Material 2018 Edition, IAEA, SSR-6 (Rev. 1). New and updated values are available, for example, for the nuclides Tb-149, Sr-83, Ni-57, Ir-193m, Kr-79, Ge-69, Ba-135m, Tb-161, Te-121m. These new and updated values are available within the e-Ship++ application.
SSR-6 2018
Regulations for the Safe Transport of Radioactive Material 2018 Edition, IAEA, SSR-6 (Rev. 1), page 25 (page 45 in pdf)

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