A large acceptance spectrometer using wire chambers

Abstract A large acceptance magnetic spectrometer has been constructed for an experiment on the π 0 -photoproduction off hydrogen and proton Compton scattering with the 1.3 GeV electron synchrotron at the Institute for Nuclear Study, University of Tokyo. The spectrometer system consists of four multiwire proportional chambers, six wire spark chambers and scintillation counters. The system has worked smoothly under high background events from electromagnetic processes. The performance, construction and monitoring system of the spectrometer are described.