Issues Not Covered by the PSF subgroup meeting
I have plotted the azimuthally averaged PSF from the SAOsac on-orbit
raytrace files which I used for the demonstration PSF image library.
The plots here are at 1um resolution and the error bars are from
counting statistics. The azimuthal sums were done using imcnts in
PROS.
To quantify how well these images can be used to determine the
PSF I resampled the data to HRC resolution (18um) and fit the data
for 0.523, 1.49 and 8.05 keV with two Gaussians and a power law.
For each of these fits I assumed that the Gaussian center is known.
| Energy (keV) | % error GW1 | % error GW2 | %error PL |
0.532 | 8% | unconstrained | 24% |
1.49 | 6% | 28% | 32% |
8.05 | 6% | 12% | 30% |
|
|
It should be noted that the fitting done above is optimistic. If
azimuthal summing is not warrented then the results will be much
less accurate.
Accurate grating simulations will be next to impossible.
The total number of rays at 1.49 keV is 7875. The MEG first order
efficiency is ~20% which will put only 1600 counts in a line.