Recent progress with very forward calorimeters for linear colliders

Recent developments for very compact calorimeters designed for precise luminosity measurement (LumiCal) and beam monitoring (BeamCal) in the very-forward region of future linear colliders are presented. Silicon pad sensors for LumiCal have been equipped with modern read-out electronics and tested in the laboratory. Ultra-compact assemblies of these sensors, with only 1 mm spacing between tungsten absorber plates, have been developed. This stack has been exposed to few-GeV electron and muon test beams at CERN and DESY. First results on shower development in such a compact stack are presented and compared to Geant4 simulations.