HIGH RESOLUTION PHOTOIONIZATION CROSS SECTIONS OF ARGON AND KRYPTON IN THE VICINITY OF THE SUBVALENCE NS-THRESHOLD S.Lauer*, H.Liebel*, F.Vollweiler*, R.M=FCller-Albrecht*, H.Steffes*, H.Schmoranzer*, G.Reichardt#, V.L.Sukhorukov+, B.M.Lagutin+, I.D.Petrov+, Ph.V.Demekhin+, K.-H.Schartner$, G.Mentzel$, O.Wilhelmi$ *Fachbereich Physik, Universit=E4t Kaiserslautern, D-67653 Kaiserslautern= , Germany #BESSY, Lentzeallee 100, D-14195 Berlin, Germany +Rostov State University of Transport Communications, RUS-344038 Rostov-on-Don, Russia $I.Physikalisches Institut, Justus-Liebig-Universit=E4t Giessen, D-35392 Giessen, Germany Photon-induced fluorescence spectroscopy (PIFS) was applied for a high-resolution study of the absolute Ar 3s- and Kr 4s-electron photoionization (PI) cross sections near their thresholds. The resonance structures in the ns-PI cross sections were compared with the resonance structures in the total PI cross sections. Theoretical results obtained by using many-body perturbation theory (MBPT) with configuration interaction (CI) techniques are presented.