XMM-Newton Users' Handbook

A..3.2 MSim - The Mirror Simulator

MSim simulates the X-ray response of XMM-Newton's mirror modules. Therefore, it can also be called a ``ray tracer''. Not only the imaging characteristics of the mirrors, but also losses on the way from the entrance aperture to the detector surfaces are modeled.

MSim is an important part of the XMM-Newton calibration activities, because it is the software module producing the empirical descriptions of such basic quantities as the mirror PSF and the effective area, $A_e$. MSim is a highly configurable software module that allows to take into account many free parameters. There is a number of mirror models included, but the default telescopes configurations mentioned above (A.2) are recommended for standard simulations.

MSim simulates the following features:

• X-ray baffle plates with tolerancing on the centering and radii

• spider with tapered spokes

• nest with deformed mirror shells; included are Fourier-Legendre deformations, roll-off, polynomial distortions, spider fixation distortions, non-uniform thickness, tilt and decentre.

• reflection coefficients of nickel and gold, taking into account the density, dust contamination and energy and angle dependent absorption.

• scattering of gold and nickel surfaces, modeled with a power-law power spectral density of the surface roughness, a tabular specification of the PSD or Gaussian scattering.

• electron deflector

• misalignment of all parts of the module

• misalignment of the entire module with respect to the satellite