EXPERIENCE WITH FOIL SPARK CHAMBERS IN HIGH PULSED MAGNETIC FIELDS

Small, thin-foil spark chambers were tested in the fringing field of a powerful pulsed solenoid. The pulse duration was 0.9 msec, and the peak field at the center of the magnet was 200 kG. A low-intensity 1.5 Bev/c pion beam from the Bevatron was directed down the axis of the coil and through the spark chamber at the end of the magnet. Pictures were taken with the field on and with the field off. No difference in the appearance of tracks with and without field was discerned. It is concluded that stainless-steel foil spark chambers can be used satisfactorily in pulsed magnetic fields. (A.G.W.)