Accurate determination of background scattered electrons in crossed electron- and gas-beam experiments using a movable gas beam source

We present the design and application of a movable collimated gas source of atomic and molecular species that allows the accurate determination of background-scattered electrons in beam-beam, low-energy electron scattering experiments. Our method provides a very simple solution for accurate background determination without using conventional 'choppers' or background gas-shunt lines. Further, it is more robust than existing conventional methods and extremely practical.