D. N. Michael

A large area high efficiency γ-ray detector with good time and space resolution☆

Abstract We describe the construction of a large area high efficiency γ detector for use in the 30 to 1000 MeV range. Its basic principle is the combination of lead-scintillator sandwich counters with optical spark chambers to achieve high γ efficiency along with good space and time resolution. The scintillator is arranged in the form of a hodoscope so that the spark chambers could be triggered on a selected number of simultaneous γ-rays. The performance in terms of γ efficiency, energy and direction resolution, and shower development are discussed.

Search for the decay πO → 4γ☆

Abstract We have searched for the decay πO → 4γ using the decay K± → π±πO as a source of kinematically defined πO,s. No events were observed, where one event would correspond to a branching ratio (πO → 4γ)/(πO → 2γ) of 2.7 × 10−5.

A proportional wire chamber system for beam definition in precision total cross section measurements

Abstract We have developed and extensively used a PWC system in precision measurements of total cross sections at low momenta (0.4–1.1 GeV/ c ) and at high momenta (23–370 GeV/ c ). This “electronic collimator” operated simultaneously in a fast (250 ns) decision making mode, and a slower (0.5 ms) readout mode. The decision making mode utilized adjustable hardwired logic to define acceptable incident beam trajectories and reject multiple beam tracks. A sample of the events was read into an on-line computer for beam tuning, for chamber diagnostics, and for study of the effect of small angle scattering to verify the total cross section extrapolation procedure.

Precision Measurements of K± and P Total Cross Sections on Hydrogen and Deuterium below 1.1 GEV/C

We present precision measurements of K± and p total cross sections on both hydrogen and deuterium in the momentum range from 400 to 1100 MeV/c. Structures are seen in all of the channels.