MONTE-CARLO CALCULATIONS FOR THE DESIGN OF MOTT SCATTERING SPIN POLARIMETERS

Using the Monte Carlo method, we have calculated, for 50 keV electrons incident on a gold target, the dependence of the effective Sherman as ymmetry function and scattered intensity on the target thickness and i nelastic energy loss window for scattering angles from 90 degrees to 1 80 degrees. Our results-show that, when the gold target is thicker tha n 700 Angstrom or the inelastic energy loss window is larger than 1200 eV, the scattered intensity is maximum at a scattering angle of about 120 degrees, and the effective Sherman function is almost constant ov er a wide range of scattering angles. Thus, for Mott scattering spin p olarimeters, the electron detectors should be positioned at +/-120 deg rees, and the larger the collection angle for scattered electrons, the higher the efficiency of the Mott polarimeter. (C) 1997 American Inst itute of Physics. [S0034-6748(97)02911-0].