Synthetic cesium aluminosilicates in the form of &bgr;‐eucryptite (Cs2O⋅Al2O3⋅2SiO2) and spodumene (Cs2O⋅Al2O3⋅4SiO2) were used to construct thermionic emitters of Cs+ions. Total ion emission current and purity of ion emission of Cs+ions for these two forms of aluminosilicates were studied and compared at four different material surface temperatures over 50 h of continuous heating. In addition, the ion emission characteristics were investigated for three other compositions of cesium aluminosilicates. It was revealed that as a Cs+ion source, &bgr;‐eucryptite gives the optimum ion emission at the temperature of 1100 °C. ©1994 American Institute of Physics.