Low-density polyurethane foam plate spark chamber

Abstract

Development of a mu1ti~gap. low-density visual spark chamber is described. Tpe design has been used successfully to make spark chambers up to 2600 in. 2 in area with very uniform gap spacing. Individual plate thickness is approximately 0.125 in. Density per plate is approximately 29 mg/cc. or the radiation length equivalent to approximately 2 mils of aluminum. The chambers have been pulsed in a Bevatron experiment over 2.5X10 6 times with good efficiency.

Radiative Pion Capture inC12

“…To minimize multiple scattering and energy loss the spark chambers were constructed of lowmass material (20 mg per gap). 9 Tracks were recorded photographically and have been measured on semiautomatic measuring machines. The trigger for an event was a stopped pion and a coincidence between any two nonadjacent pairs of counters out of the six mounted in front of the magnet (see Fig.…”