Lifetime Histograms Settings

The Lifetime Histograms Settings page displays optional corrections used in TCSPC-compatible SPAD array data analysis.

1. TAC Bin Sizes (ns)

The TAC Bin Sizes (ns) array is used to convert photon nanotime timestamps (in TAC unit) to real time units (ns). These parameters are used instead of the TAC Bin (ns) parameter shown on the Data File page, which is equal to the average of the different TAC Bin Sizes (ns) values in the array.

As for other settings, this array is saved when ALiX is closed, and reloaded when it is started again.

When a SPAD array .dat file containing its own TAC Bin Sizes (ns) array is loaded, the file values overwrite the previous values in the Lifetime Histograms tab.

The user can modify these values at any time, in which case they will be used instead of the original data file values.

2. Decay Shifts (ns)

The Decay Shifts (ns) array is used to align the lifetime decay histograms of all channels to that of channel 0.

This value is typically obtained by measuring the offset of each channel's IRF (loaded as Acceptor channel) to that of channel 0 (loaded as Donor channel), using the Autocorrect Channel Shift checkbox on the Nanotime Display page (specifying first an Acceptor Offset (ns) value of zero). The resulting calculated Acceptor Offset (ns) value can then be copied in the Decay Shifts (ns) array. This procedure needs to be done only once, since, as for other settings, this array is saved when ALiX is closed, and reloaded when it is started again.