Response of Multiwire Proportional Chambers to Relativistic Heavy Nuclei

Measurements have been carried out at the Lawrence Berkeley Laboratory Bevatron to investigate the response of multiwire proportional chambers to 2. 1 GeV/nucleon C12 and O16 nuclei. The relative gas gain as a function of high voltage was measured for three different gases: 80% Ar/20%CO2, 75% Ar/ 25%C4H10, and 81% Ar/14% Xe/5%CO2. The gas gain obtained with 5.9 KeV X-rays from Fe55 sources was also measured for comparison. Saturation characteristics of the chambers are analyzed and the implications of the results on the use of multiwire proportional chambers as spatial detectors in cosmic ray experiments are discussed. A summary of the results of delta ray calculations and their effect on spatial resolution is also presented.