A system of large multiwire proportional chambers for a high intensity experiment

Abstract We describe a system of three multiwire proportional chambers used in the experiment NA24 at CERN. Each chamber consists of four wire planes (2 × 2 m 2 sensitive area), packed together in the same mechanical frame with only five cathode foils. All planes are electrically independent and can be operated individually although each of the three inner cathode foils is used for two adjacent wire planes. Another feature of the chamber is that an area around the beam can be desensitized to allow operation in a high intensity beam.