The new drift chamber for the Mark II detector at the SLAC linear collider

Abstract A new central drift chamber has been constructed for the Mark II detector for use the new SLAC Linear Collider. The design of the new chamber is based on a multi-sense-wire cell of the jet-chamber type. In addition to driftime measurements, pulse-height measurements from the sense wires provide electron-hadron separation by d E /d x . The chamber has been installed in the detector and is being at PEP before being moved to the SLC. The design and construction of the chamber, as well as initial performance results from the PEP data, are presented.