Tuning Parameters

There are several quantities used in the simulators that must be tuned in order to get the simulations to reproduce adequately the XRCF PSF data.

• Focus - can be adjusted to match the data fairly well just by examining the rays (we used the ``dataset_2d'' tool, part of the TARA package, and the MARX output files ``xpixel.dat'' and ``ypixel.dat''), since this parameter is controlled by MARX.
• Flux - tuning the flux is crucial for reproducing XRCF data, since this is the way to reproduce and explore pile-up. The current analysis suffers from a lack of flux tuning capability, but this will hopefully be available in the next MARX release. For now, we have forced the simulator to the idealized state of exactly one photon per frame.
• FAM orientation (CHIPX & CHIPY offsets, rotation) - we have implemented the ability to adjust the position of the PSF in CHIPX and CHIPY, but have not yet explored the possibility of rotation.
• Others? - As we tune the above parameters and improve the simulator, we may discover other parameters whose tuning allows us to reproduce the data more accurately. We remain alert for such potential adjustments.