Abstract: Based on traditional alpha radiation detection technology for detecting nearby distances, using the principle of alpha radiation particles inducing air fluorescence, remote measurement of alpha radiation activity can be achieved. By establishing a model for alpha activity measurement based on point sources, and using photomultiplier tubes to measure the photons induced by alpha radiation, an empirical formula relating the source activity to the net photon counting rate of the photomultiplier tube was developed. The study investigated the factors influencing fluorescence conversion efficiency by changing radiation sources of different energies, altering media, and varying pressures. The results showed that the fluorescence conversion efficiency of ²⁴¹Am source in air to be 3.24×10⁻⁶ -7.83×10⁻⁶. Sources with higher energy exhibit higher fluorescence conversion efficiency. Pressure shows a linear positive correlation with fluorescence conversion efficiency. Among air, nitrogen, and argon, argon gas was found to effectively enhance the fluorescence efficiency The empirical formula can be used for calculating the activity of radioactive sources. Investigating the factors influencing fluorescence conversion efficiency provides data references for improving the efficiency and accuracy of remote α radiation detection.