Signal Types ("Flavors")

Now, each of these signals can come in different "flavors", which means it can be calibrated differently. For instance, the signal recorded by a photon counter could be given as total number of photons transmitted, or it could be calibrated as photon count rate, that means photons per second. Obviously, this calibration involves only a division by dwell time. In the case of the segmented silicon detector, the signal could be given as a voltage, or be converted to a photon count rate.

The case of the segmented silicon detector requires an additional complication of the story. The reason why we use a segmented detector at all is that certain combinations of segments allow different contrast modes. Adding up all segments gives you a regular "bright field" image (as in the case of the proportional counter), but subtracting the signals of opposing segments from each other gives you a "differential phase contrast" image. Therefore, the STXM 5 software also allows for certain pre-defined linear combinations of detector channels.

Still following? Ok, let's go into the details. SM_GUI as well as the command-line based file-reading tools allow you to look at the images in the following signal types, or "flavors". We look at them in the order of increasing complication from a data point of view, which is the opposite of what the user will be interested in.