Design Curves for 180° Magnetic Spectrometers

The image shapes resulting from 180° focusing of charged particles in a homogeneous magnetic field have been computed. General curves are presented in terms of three variables for variable ρ-spectrometers (as in the case of photographic detection) and in terms of four variables for constant ρ-spectrometers (as in the case of detection with a fixed counter). The variables are source and exit-slit height, source width, angular selection, and exit-slit width. The advantages of using sources and exit-slits with a large dimension parallel to the magnetic field (i.e., height) are noted.