Archive for August, 2019

Build up factor interpolation

August 21st, 2019

(Qu.) SG SCK-CEN, Belgium
Dear Nucleonica Team,
As shown below is the buildup factor equal to 1 at a distance of 15 m in air for gammas with an energy of 1 MeV.
My assumption would be that for a number of mean free paths of 0 the buildup factor would be 1. If this is the case, the buildup factor at 15 meters (mfp = 0.1107) should be interpolated between 1 (the buildup factor at mfp=0) and 1.47 (the buildup factor at mfp=0.5). If I do this I get a buildup factor of 1.104.
Am I wrong in my assumption or does Nucleonica interpolate differently? (Logarithmic or spline interpolation instead of linear interpolation what is shown in the help menu).

Buildup factor interpolation

(Ans. Nucleonica Team)
Until now the buildup factor was extrapolated for a given energy from the two last tabulated values µd=0.5 and µd = 1 when µd < 0.5. But since BU = 1 for µd = 0 interpolating between µd = 0 and µd = 0.5 is a better approach and will be realised by the next deployment. Thanks again for your observations.

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Nucleonica Physical Constants updated to 2018 CODATA recommended values

August 13th, 2019

The values of the physical constants used in Nucleonica are recommended by CODATA and are the latest available. Termed the “2018 CODATA recommended values” they are recognized worldwide for use in science and technology. The values became available on 20 May 2019 and replaced the 2014 CODATA set. They are based on all data available until 31 December 2018.NewPCs-2019Of particular important to the Nucleonica applications, IUPAC is recommending a new definition of the mole based on a specified number of elementary entities:
The mole, symbol mol, is the SI unit of amount of substance. One mole contains exactly 6.022 140 76 × 1023 elementary entities. This number is the fixed numerical value of the Avogadro constant, NA, when expressed in mol−1, and is called the Avogadro number.
More information
2019 redefinition of the SI base units
A new definition for the mole based on the Avogadro constant

Posted in Karlsruhe Nuclide Chart, Nucleonica | Comments (0)

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