3.1.3.1 Event Recognition

When a pixel contains data above the Event Recognition Threshold, that pixel and the surrounding 3x3 neighborhood are selected for post-processing. At that point, depending on the selected processing mode, the software must either attempt an X-ray energy reconstruction on-board the instrument, or telemeter the entire 3x3 data set to the ground. If the overall counting rate in the CCD is low enough the `Faint' mode is used, but otherwise the `Bright' mode must be used.

Faint Mode

The recognized event is telemetered as a 3x3 local neighborhood, centered on the peak pixel. In this mode the detector x,y position and 9 CCD pixel values are processed and telemetered. The processing system is adequate to process an input event stream of up to 180 events/sec.

Very Faint Mode

The recognized event is telemetered as a 5x5 local neighborhood, centered on the peak pixel. In this mode the detector x,y position and 25 CCD pixel values are processed and telemetered. The processing system is adequate to process an input event stream of up to 180 events/sec.

Bright Mode

The recognized event is telemetered as a single charge value, reconstructed from the 3x3 local neighborhood by summing according to a specified split event algorithm. In this mode the x,y position, a single reconstructed CCD pixel value, and a quality flag indicating the type of event are telemetered. The processing system is adequate to process an input event stream of up to 750 events/sec.