“…Such a detector had many advantages. It was a low density gas target, and, at the same time, it was triggerable, offering a 4π acceptance in which highly luminous localized particle tracks could be obtained [2]. The low density of Figure 1: Layout of the PS 179 experimental apparatus, including: EMelectromagnet; SC-streamer chamber; HVPG-high voltage generator; TPtravelling platform; ES-electrostatic screening; W C 1−2 -wire chambers; C 1−6 -scintillation counters; M 1−5 -thin walls.…”