Progress Report on an Ultra-compact LumiCal

Abstract: A new design of a detector module of submillimeter thickness for an electromagnetic calorimeter is presented. It is aimed to be used in the luminometers LumiCal and BeamCal in future linear e$^{+}$e$^{-}$ collider experiments. The module prototypes were produced utilizing novel connectivity schemes technologies. They are installed in a compact prototype of the calorimeter and tested at DESY with an electron beam of 1 GeV $-$ 6 GeV. The performance of eight detector modules and the possibility of electron and photon identification is studied.