A study of Ar + C2H4 and Xe + CF4 gas mixtures

Mixtures of Ar + 40 ppm C₂H₄ and 50% Xe + 50%CF₄ have been investigated. The spatial distributions of photoelectron clouds produced by primary scintillations on α- and β-particle tracks, as well as the distributions of photoelectron clouds due to photons from avalanches at the pin anode, have been measured for the first time. For a mixture of 50% Xe + 50%CF₄, it has been shown for the first time that CF₄ is a photosensitive dopant in a mixture with Xe. For a mixture of Xe + CF₄ (1: 1), the maximum electron multiplication factors at the pin anode are K(β)^max = 3 × 10⁴ and K(α)^max = 3 × 10³ at a pressure of 1 atm (abs.) and K(β)^max = 10⁴ and K(α)^max = 4 × 10³ at a pressure of 10 atm (abs.)