Large aluminium wire spark chambers with magnetostrictive read-out

A set of 1 cm gap wire spark chambers with a sensitive surface of 300 × 100 cm2 was constructed for an experiment at the CERN proton synchrotron. The Coulomb scattering was limited by using aluminium wires and by adopting a crossed-wire configuration, which allowed us to minimize the number of chambers for a given number of pairs of coordinates. The wire planes were pulsed by feeding the high voltage from strip-lines along the whole boundary of the chambers.