The GoldSim RT Module provides some specialized features to assist in simulation of radioactive species. For practical reasons, you may often wish to enter and present inventories, concentrations, quantities and flux rates for radioactive species in terms of activity. As used here, the activity of a radioactive species represents the number of disintegrations per unit time (and should not be confused with the thermodynamic activity of a species).
To facilitate this, GoldSim allows you to specify that a species is radioactive. If the Radioactive checkbox is checked, GoldSim displays the specific activity. (The Radioactive checkbox is cleared and grayed out in the CT Module).
The specific activity has units of activity per unit mass and is computed as:
(Avogadro's Number)(Decay Rate) / (Atomic Weight)
Activity (disintegrations per unit time) is measured in units of Becquerels (Bq) or Curies (Ci), so specific activity has units of Bq or Ci per unit mass. A drop-down list allows you to specify which of these units you wish to use.
In addition to displaying the specific activity here, the Species element always produces a vector output consisting of the specific activities of each of the species. Note that, by definition, the specific activity of a non-radioactive species is zero.
Note: Some radioactive species
decay into multiple daughter products (e.g., 95% of the disintegrations may
produce species A, and 5% may produce species B). In this case, you should
use the Stoichiometry to specify this "splitting". In this example, the
Stoichiometry would be 0.95 for the first daughter, and 0.05 for the second
daughter.
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