Cosmic ray studies with a gas Cherenkov counter in association with an ionization spectrometer

Abstract

The results from a balloon borne gas Cherenkov counter (threshold 16.5 GeV/ nucleon) and an ionization spectrometer are presented. The gas Cherenkov counter provides an absolute energy calibration for the response of the calorimeter for 5 < Z < 26 nuclei of cosmic rays. The contribution of scintillation to the gas Cherenkov pulse height has been obtained by independently selecting particles below the gas Cherenkov threshold using the ionization spectrometer. Energy spectra were derived by minimizing the X'" between a Monte Carlo simulated data and flight data. Best fit power laws (dN/dE = AE-1 ) were determined for C, N, O, Ne, Mg, and Si. The power laws, all consistent with E-2.7 , are not good fits to the data.A better fit is obtained using the spectrum derived from the spectrometer. The data from the ionization calorimeter (Simon, et al., 1980) and the gas Cherenkov are thus completely self-consistent.