A method to extract the Stokes parameter describing circularly polarized co
mponents of VUV light from suitably selected photoelectron Auger electron c
oincidences is demonstrated for 2p photoionization in magnesium with subseq
uent L-2,L-3-M1M1 Auger decay. Including the standard technique of non-coin
cident angle-resolved photoelectron spectrometry to obtain the Stokes param
eters describing linearly polarized components of VUV light, the full polar
ization properties of VUV light have been measured, as an example, for 80 e
V photons delivered from the TGM4 monochromator at BESSY I in Berlin.