CCD pile-up model used for brightish point sources observed by Chandra. This is an implementation of the fast pile-up algorithm proposed by John Davis (see http://space.mit.edu/davis/papers/pileup2001.pdf). The frame time and maximum number of photons to pile up should be fixed. The grade morphing is expressed through a single parameter, alpha, which should be left as a free parameter. Note that to calculate fluxes etc. for the model you must remove the pileup component.
|par1||=||frame time (in seconds)|
|par2||=||maximum number of photons to pile up|
|par3||=||grade correction for single photon detection|
|par4||=||grade morphing parameter (good grade fraction is assumed proportional to par4(p-1) where p is the number of piled photons)|
|par5||=||PSF fraction. Only this fraction will be treated for pile-up|
|par6||=||Number of regions. The counts to be piled-up will be distributed among par6 regions, which will be piled-up independently.|