The CDF II detector at Fermilab is designed to study proton - antiproton collisions at 2 TeV center-of-mass energy. Built on the foundations of CDF I, CDF II will operate at a factor 20 increased luminosity with entirely new vertex and central tracking devices, new plug scintillator calorimetry, new front end, trigger, and data acquisition electronics, and extended muon coverage.

The intermediate angle muon system (IMU) identifies muons over rapidity ~1-1.5 by a 4-layer barrel of drift tubes (BMU) and scintillators (WSU, BSU, TSU). This working design document describes the  BMU system.