Muonic, Pionic, Kaonic and ∑- X-Rays, Atomic De-Excitation Cascades, and Nuclear Absorption Rates in He, Li, Be, and C

Large xenon-filled proportional counters were used to obtain sufficient solid angle for efficient x-ray detection from a 12-in. long liquid He target. Mesons came from an unseparated 850-MeV/c beam produced at 0° by the external proton beam. Muons or pions were selected by a threshold Cerenkov counter, kaons by means of a pair of Fitch-type Cerenkov counters in a time-of-flight arranglent that provided a stopping K- signal of greater than 99.5% purity2. True and delayed (background) coincidence rates were simultaneously recorded.