Primary scintillation characteristics of Ar+CF4 gas mixtures excited by proton and alpha particles

In this paper, we report how the concentration of carbon-tetrafluoride (CF4) affects the primary scintillation from Ar+CF4 gas mixtures excited by proton and alpha particles. The single photon counting method was used to measure the time spectra of the primary scintillation from Ar, CF4 and their mixtures at atmospheric pressure. Pure Ar exhibits a fast decay time constant, which is approximately 6 ns, and a slow decay time tail. Initially, increases in the concentration of CF4 increase the decay time of the Ar+CF4 gas mixture. However, when the concentration of CF4 exceeds a certain threshold, the decay time decreases to that of pure CF4, approximately 8-9 ns. We also report the photon emission spectra of Ar+CF4 mixtures excited by protons. The emission spectrum of the primary scintillation from Ar is improved by CF4 in both the ultraviolet region and the visible to near-infrared region.