The objective is to find the energy-dependent geometric factor for the deflected electrons of HISCALE.  The method of approach is identical to that of Shodhan³, and much of the software needed to implement the following steps is adopted from her work.  Basically, there are four main tasks one must accomplish.

1. Model the geometry of the detector and telescope system, picking an appropriate coordinate system.

2. Model the magnetic field created by the deflecting magnets.

3. Determine the solid angle of electron trajectories that escape the sensor system for a specified area on the detector, and sum over all these areas to obtain G.

4. Repeat steps 1-3 for different electron energies.

Step 1.  Modeling the Detector and Telescope

Shodhan's method works on the assumption that the entire subsystem is modeled with plane polygons.  To model the detector and telescope for the deflected electrons, the first step was to obtain the mechanical drawings of the HISCALE instrument, an example of which is shown in Figure A9-5.  Next, a suitable origin must be chosen.  Since Shodhan's software is used, it is important to adopt her coordinate system and a similar origin.  The resulting coordinate system shown with respect to the rest of the HISCALE instrument is shown in Figure A9-6, and the resulting model for the geometry is shown in Figures A9-7a, b, c.

A listing of the coordinate labels, as well as plane coefficients needed in the software, is given in Section A9.5.