pileup: CCD pile-up model for Chandra
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. This model should be considered in beta test. Note that to calculate fluxes etc. for the model you must remove the pileup component. The pile-up model is similar to the operation of the convolution models, differing only in the treatment of the detector efficiency during the convolution.
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 par4p-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. |