I know there are two kinds of detectors which resolve spin polarization in spin-resolved ARPES experiments. one is a Mott-type detector and the other is a VLEED-type detector. the former uses the asymmetry of Mott scattering caused by spin-orbit interaction of a heavy atom(e.g. Au). I almost understand the principle of Mott detector, but I do not understand the principle of the latter. could someone explain this?
In addition, I have heard that a VLEED-type detector is better, but I do not know how better it is. Please teach me.