Large proportional chambers for muon detection in the CELLO experiment at petra

Abstract We describe the muon detector in the CELLO experiment. This detector is composed of one layer of proportional chambers placed after a total of 5 interaction lengths of matter. These chambers have cathode read-out, thus enabling the unambiguous determination of coordinates. A total of 32 chambers has been built in order to cover 95% of the total solid angle. The read-out electronics use the FILAS integrated chips made by EFCIS. Data concentration is done by a multiplexing system which addresses only those chambers which have some information. The precision is poor, but sufficient for muon detection: σ = ±6 mm.