After you initiated the creation of a new source entry, the source editor window appears.

Specify a descriptive name for the source in the Name field, then click Isomers tab to define the contained isotopes.

In HyperLab terminology, the source requires only the identification of isomers – and not the decays starting from that isomer level –, because it is always guaranteed that a source provides gamma radiations from all possible decays which are originated from an isomer state.

To add a new isomer entry to this source, click Add isomer button.

The isomer selector window appears now.

For our sample source, select 60Co isomer with 5.27 year half-life. To speed up the selection process, quickly type in the first few letters of the isomer, and the list will scroll to the specified position.

You can also browse the decays and the associated gamma radiations for the isomers.

When you are ready, click OK.

The source editor's Isomer page appears again, and the list of assigned isomers contains the selected item. Now place a check “Activity is calibrated”, and type in the certified calibration values. For the “Co-60 OMH 85-185” source of the sample spectra set, specify 434.60 kBq activity and 0.7 % activity uncertainty, then 1 Oct 1985 12:00 as the calibration date.