Work function of polycrystalline rhenium

The work function of a polycrystalline rhenium surface in a cesium atmosphere was measured for a wide range of surface temperature (700 to 2100°K) and cesium pressure (0.0001 to 2.0 mm Hg.). The work function is found to depend only on the ratio T
e
/T
R
of the emitter to cesium reservoir temperatures. A map of the emission properties of rhenium is given.