Precision liquid hydrogen rapid cycling bubble chamber

Abstract A precision liquid hydrogen bubble chamber with rapid cycling capability and a photographed volume of 150 × 70 × 50 mm 3 has been constructed to study short-living elementary particles. Its refrigeration system is operated with liquid helium. The chamber body, manufactured from the polycarbonate Lexan ® , is almost free of vibrations due to the innovative expansion system with two pistons operating in opposite directions. The chamber operates with 5 ms cycle time and a rate up to 30 s −1 . The chamber has already been cycled 6.7 million times and about 0.3 million pictures have been taken. At the hydrogen temperature of 29.8 K a track density of 150 bubbles/cm has been achieved with bubble diameters of 25 μm.