Measurement of electron loss cross sections for 0.25‐ to 5‐keV hydrogen atoms in atmospheric gases

Absolute electron loss cross sections have been measured for fast hydrogen atoms incident on He, H 2 , N 2 , O 2 , CO, CO 2 , and CH 4 in the 0.25‐ to 5‐keV energy range important in studies of proton aurorae. The fast hydrogen atoms produced by charge transfer passed through a cell containing the target gas. The current of fast protons arising from electron loss collisions of these H atoms with the target gas was measured. Particular attention was paid to complete collection of product ions and to elimination of effects resulting from nonuniform pressure distributions near the gas cell orifices. Techniques for absolute determination of fast hydrogen atom flux are also described.