Fig. 4. The decrease with time of the amount of ⁴⁴Ti in the supernova remnant, , by -decays, starting from the initial amount (right scale in logarithm), and the corresponding, mostly increasing activity ratio (left scale ). Values of 3 (upper panel ) and 5 (lower ) are used for , while erg, cm^-3 and are adopted in both cases. The different lines show results obtained for different assumptions of the radial locations of the clumps: = [0.0, 0.5] (solid line ), [0.4, 0.6] (dash-dotted line ), and [0.2, 0.8] (dashed line ). The exponential decrease of the ⁴⁴Ti abundance with the laboratory rate is plotted by the dotted line