This design proved quite successful, and the detector was used in discoveries of the J/ψ particle and tau lepton, which both resulted in Nobel Prizes (for Burton Richter in 1976 and Martin Lewis Perl in 1995).
A solenoid coil generated a magnetic field roughly parallel to the beam direction, which enabled measurement of the transverse momentum of particles emerging from the collision point.
Design and construction of these detectors were overseen by Roy Schwitters of the SLAC collaboration Sandwiched between the outermost cylindrical wire chamber and the magnetic coil were 48 scintillation counters.
Again, light pulses generated by the passage of charged particles traversing these counters were detected by photo-multiplier tubes at each end and associated electronics.
A solenoid coil was powered with DC current to produce a .4 T (check) magnetic field, to bend charged particles in the plane perpendicular to the beam.
This made it possible to detect tracks in three dimensions, and measure charged particles, to determine if they originated from the interaction region of the beam pipe.