Compute ACFs Script

This script goes through all the selected (or all) channels individually (depending on the Use All Channels switch located on the left hand side of the page), and computing the ACF for this channel according to the definitions set in the Correlation page.

If the Compute & Save Mean Count Rate checkbox (see below) is checked, an additional step of mean count rate calculation (involving computing the PIH and the corresponding average count rate) is inserted. The value of the current mean count rate will be displayed in the Mean Count Rate A (Hz) indicator to the right of the ACFs button.

The corresponding ACF curve (and mean count rate if requested) is then saved as an ASCII file in the same folder as the original file, with the name:

Data_File_Name_ACF of Ch Channel_Name.txt

where Data_File_Name is the data file name without its extension and Channel_Name is the channel name as read on the Data File page. Note that in order to result in a valid file name, any character "\" or ":" in Channel_Name will be replaced by an underscore character.

Since different channels can have different definitions (Donor or Acceptor) and since the ACF calculation is performed as defined in the Correlation page, different strategies may need to be used in different cases.

For instance, if the user is interested in computing the ACFs of all photons in all channels of a smFRET sample, the ACF to be computed is the All_Photons one.

If on the other hand, the user is interested in computing all F_D^D and F_D^A stream ACFs, it will be necessary to run two scripts:

• • a first script in which only the Donor channels are selected (this will result in a warning, but it will be ignored by the script) and the F_D^D ACF is computed.

  • a second script in which only the Acceptor channels are selected (this will result in a warning, but it will be ignored by the script) and the F_D^A ACF is computed.