We present predictions of the total HRMA off-axis effective area (within 2pi steradians). Previous on-axis effective area predictions were adjusted to take into account known differences between simulated and measured XRCF effective areas. We have not done so in this presentation (even for the on-axis results), as we are still determining the appropriate nature and magnitude of such corrections for off-axis measurements.
The simulations were performed using trace-shellz3
and the
orbit_XRCF+tilts_01
configuration. Source positions are in the HSC1.1 (HRMA
Spherical Coordinate) system; radial angles are specified in
minutes of arc, while azimuthal angles are specified in degrees.
The energy grid is currently somewhat coarse (every 100eV). The
quoted errors are based upon the number of rays in the
simulations.
Two areas of immediate note are the "feature" near 1keV and the changes in effective area as a function of source azimuth. The first is due to a discontinuity in the optical constants at 940eV. We use Gullikson 95 constants below 940eV and the MST Synchrotron measurements above it. The variation in effective area with source azimuth (see, for example, theta = 25') is due to the decenter of the optics.