The production of ionization and Cerenkov radiation by cosmic ray muons

Abstract

The details of the construction of a new horizontal spectrograph using neon flash tubes, plastic scintillators and an air-gap magnet are given. A detailed description of a water Cerenkov counter is also presented. Both the Cerenkov radiation loss in water and the ionization loss in a plastic scintillator have been investigated using cosmic ray muons in the momentum range 0.355 - 100 GeV/c. The results on the Cerenkov loss show that there is no significant change of Cerenkov intensity at particle momentum above 1 GeV/c. As such, the results are in good agreement with the classical theory of Frank and Tamm, and do not support the suggested suppression effect of Tsytovich (1963). Similarly they contradict the experiment, at high momentum, by Bassi et al. (1952), in which an anomalously large increase in Cerenkov loss was found. The results on the ionization loss in the momentum range 10 - 100 GeV/c are consistent with the theory of Sternheimer (1952, 1953). No significant decrease was found in the values of most probable ionization loss in the above momentum range, again in contradiction to the theory of Tsytovich.