growth curve 

of activity
https://doi.org/10.1351/goldbook.G02708
Curve giving the activity of a radioactive nuclide as a function of time and showing the increase of the activity through the decay of the precursor or as a result of activation.
Source:
PAC, 1994, 66, 2513. (Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)) on page 2520 [Terms] [Paper]