Works only for 1CCD mode observations. This task divides the event file into many time segments, and calculates pile-up for each segment separately, so that effect of the attitude fluctuation is taken into account. Pileup is corrected in the following manner.
Chip is divided into many annuli so that each annulus has approximately a constant flux level.
The on-board event detection algorithm is applied on the virtual chip. Note that the number of the simulated events detected on the virtual chip should be less or equal to N due to pile-up. The simulated events detected on the virtual chip are recorded as pha2. 5. Statistical error of the output pha file is calculated assuming that events in pha0 and pha3 follow the Poisson distribution. The input event file.