The LSF's are extracted from the simulations in the dispersion and cross-dispersion directions using the same 5.3 region used for the library files. These profiles are then fit with a Gaussian function with the center, width, and normalization free to vary. These fits are done using the IDL fitting routine curvefit. In general the Gaussian fits the central part of the line profile reasonably well but the outer parts of the profile, the wings, are systematically broader than a Gaussian (see figures 6,7). This can be seen in the fits and the plots where very large values of are seen in the outer regions. The absolute value of is determined using only statistical errors of the simulation and ignore any calibration uncertainties for this calculation.
Plots of the Gaussian width vs Energy are given in Figure 8, 9, 10. The HEG and MEG data show clear trends of the Gaussian width with energy. The lowest energy (largest dispersion distance) shows the largest width which rapidly decreases to a fairly constant width for the MEG data. The HEG widths also decrease rapidly with increasing energy, show a minimum width at 6.4 keV, and then shows a mild increase up to 10 keV. The LETG widths (figure 10) show a steap decrease with increasing energy up to about 1 keV above which the widths are fairly constant.
Table 3.3.1 shows the resolution ( ) (as defined in HETG Ground Calibration: version 2.0 where ) for some of the measured lines shown in figure 8. Not surprisingly, these values agree well with pre-flight design predictions and with earlier predictions (see http://space.mit.edu/HETG/res_power/res_power.html).