Fast scintillation counters for the DO Muon System Upgrade

The design and main parameters of the completely redesigned DO Forward Angle Muon System (FAMUS:1.0<|/spl eta/|<2.0) for the next high luminosity Tevatron Collider run are reported. Results of the studies of trigger scintillation counters based on fast scintillator Bicron 404 A and WLS bars SOFZ-105 are presented. We report about results of test beam studies of prototype counters including minimum ionizing particles detection efficiency, time resolution and amplitude response.