Author Archive

Problem with using mixtures in DELNuS++

February 25th, 2019

Some of our users have reported that the results of a decay calculation using DELNuS++ for a mixture does not give the same result as the sum of the results for the single nuclide calculations.
As an example, the activity of Cs137 or Kr85 produced from a mixture of Cf252 and Cf250 is almost a factor two higher that from the sum of the results using the single nuclides Cf252 and then Cf250.
The problem has now been identified and resolved.
The results obtained using DELNuS++ for the mixture are now consistent with the sum of the results for the individual component nuclides. The results also agree with those obtained using the Decay Engine++ (which can also account for fission products).

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Ambient dose rates caused by different types of radiation

February 8th, 2019

Ambient dose equivalent H*(d) is the normal monitoring (area monitoring) quantity for X, gamma and neutron radiation where d is the depth at which the dose applies. International convention in radiation protection is to use the ambient dose equivalent at 10 mm depth i.e. H*(10). The ambient dose gives a conservative estimate of the effective dose a person would receive when staying at the point of the monitoring instrument (NPL).
In Nucleonica applications, the photon (X+gamma), beta, and neutron doses are calculated separately using analytical and semi-analytical formulae. To obtain the (total) ambient dose H*(d), these individual doses must be added. Following Otto, the ambient dose from a radionuclide can be represented as a sum of components caused by different radiation types, i.e.
ADR_Radiations3This is the notation which will be used in various Nucleonica applications for ambient doses and dose rates i.e.
ADR_Radiations4
For control of doses to skin and lens of eye, the directional dose equivalent is used. The directional dose equivalent denoted by H′(d) is intended for use with less penetrating radiation such a beta particles. Its main use is for skin dose at a depth of 0.07 mm. For beta radiation and electrons, for example, this is denoted as i.e. H'(0.07)e.
ADR_Radiations6

More info…
– T. Otto, Personal Dose-Equivalent Conversion Coefficients for 1252 Radionuclides, Radiation Protection Dosimetry (2016), Vol. 168, No .1, pp1-70. Link
NPL: Measurement of dose rate
Operational quantities (Wikipedia)

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World’s oldest periodic table chart found in St Andrews

January 22nd, 2019

A periodic table discovered at the University of St Andrews is thought to be the oldest in the world. Following Menedleev’s famous discovery of periodicity in the chemical elements in 1869, a number of such periodic tables were created. The St. Andrews periodic table is similar to Mendeleev’s second table from 1871. Original_PT2Periodic Table discovered at St. Andrews University, Scotland (Courtesy St. Andrews University).
The United Nations has designated 2019 as the international year of the Periodic Table of chemical elements, recognizing it as an instrument ‘central to linking cultural, economic and political aspects of the global society through a common language’.

More info…
St. Andrews University News
Article in Der Spiegel (in German)
United Nations Year of the Periodic Table

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Karlsruhe Nuclide Chart (Contour Chart) at URENCO, Netherlands

January 14th, 2019

Nucleonica has arranged the installation of a “contour” version of the Karlsruhe Nuclide Chart at the URENCO premises in Almelo, Netherlands.
The Chart was produced using a 4mm Dibond aluminium plate “cut-out” to fit in a space of height 2m and width 5m and assembled a small distance from the wall. The text is cut from adhesive foil and glued directly on the wall.
UERENCO_KNC_2018Karlsruhe Nuclide Chart (Contour Chart) at the URENCO premises in the Netherlands, Courtesy URENCO. For further information, contact info@nucleonica.com.

More information…
Other print versions of the Karlsruhe Nuclide Chart
Nuclide Charts
Contour Nuclide Chart for European Dialogue Centre

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Energy deposited in matter by nuclear and electronic stopping processes

January 14th, 2019

Qu. (from G.D. Fz-Juelich):
Dear Nucleonica Team, we have the following question regarding the energy deposited in matter by nuclear and electronic stopping processes:
We are interested in the respective contributions of nuclear stopping and electronic stopping to the (integral) energy deposited in solid materials during irradiation with heavy ions with defined energy (e.g. Au-197 ions with 5 MeV). Using the Range & Stopping Power++ App in Nucleonica, the results table provides only the values for the electronic and nuclear stopping at the materials’ surface (e.g. in keV/µm at depth 0 µm).
Bragg curve for 5MeV Au-197 on Water (liquid)
Integrating the Bragg curves (using the downloaded graph data) by the trapezoidal method suggests that the sum of the energies deposited by nuclear and electronic amounts only to 80 to 90% of the initial energy of the projectile. Is this correct (and if so, where is the remaining energy), and is there a more convenient way to directly calculate the amounts of energy deposited by each nuclear and electronic stopping, respectively, using either the Range & Stopping Power++ App in Nucleonica or SRIM/TRIM.

Ans. (Nucleonica Team)
The difference in the sum of the energies deposited by nuclear and electronic contributions come most probably from the limitations of numerical calculation procedure.
The difference is not due, for example, to Bremsstrahlung since Bremsstrahlung is considered only for light particles, i.e. incoming electrons and positrons. The R&SP++ app does not calculate Bremsstrahlung for heavy ions. This difference probably comes from the numerical procedure. Note the R&SP++ app uses the SRIM engine for heavy ions, so R&SP++ app and SRIM’s results are the same.
The Nucleonica Team will investigate this difference further.

More info…
Range and Stopping Power wiki page

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Nucleonica Newsletter 2019

January 6th, 2019

Dear Nucleonica Users,
Hopefully you had a great start into the New Year, and we wish you every success in 2019. For the Nucleonica Team, a major focus over the past year was the development and improvement of new and existing applications. Detailed information on these activities is described in this Newsletter.
A highlight in 2018 was the launch of the new 10th Edition of the Karlsruhe Nuclide Chart in early 2018. You can order your copy here.
A further highlight was the development of a new online e-Learning Training Centre, making the Nucleonica product knowledge more transparent and accessible.
NN2019The Nucleonica Team would like to thank you for your continued support.
Best wishes for 2019, Sincerely yours,
Joseph Magill, Managing Director

More information…
Nucleonica Newsletter 2019
Previous Newsletters
Nucleonica Newsletter 2018
Nucleonica Newsletter 2017
Nucleonica Newsletter 2016
Nucleonica Newsletter 2015
Nucleonica Newsletter 2014
Nucleonica Newsletter 2013
Nucleonica Newsletter 2012

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Neutron dose rate app extended to reference neutron sources

December 13th, 2018

The neutron dose rate application, previously restricted to monoenergetic neutrons, has been extended to include the spectrum averaged ambient dose equivalent coefficients for common neutron sources. This allows the user to calculate ambient dose rates for the following reference radionuclide neutron sources:
– Cf252;
– Cf252 (D2O moderated);
– Am241-B; and
– Am241-Be
NDR_2 In the example above, the neutron dose rate for 1 g Cf-252 at 1 m is 2.65e7 µSv/h and results from a neutron source strength of 2.40e12 neutrons s-1 at the source and 1.91e7 neutrons cm-2 s-1 at 1 m distance from the source.

More information…
– Neutron Dose Rate application wiki page
– Reference neutron radiations — Part 1: Characteristics and methods of production, ISO 8529-1:2001, 2001. Link. See also … link
– Neutron Shielding for a 252Cf Source. Link

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ENDF/B-VIII.0 (2018) decay data now available in Nucleonica

November 30th, 2018

On February 2, 2018, CSEWG released its latest revision of the ENDF/B library, ENDF/B-VIII.0.
The ENDF/B-VIII.0 (2018) decay data sublibrary is now available in Nucleonica in addition to the previously used decay data library JEFF3.1, and EBDF/B-VII.1. It is now possible to compare and contrast the main European (JEFF3.1) 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, etc. using Nucleonica’s user friendly tools. This data comparison can be accessed through the Options tab of the Nuclide Datasheets++ application.ENDFB8

More info…
ENDF/B-VIII.0
ENDF/B-VIII.0 Evaluated Nuclear Data Library

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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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