Electron-Capture Cross Sections for Protons Passing through Hydrogen Gas

Measurements have been made of the electron-capture cross sections ${\sigma }_c$ in hydrogen gas for protons moving with kinetic energies between 34 and 149 kev. At these energy limits, ${\sigma }_c$ has the values 1.52×${10}^{-16\mathrm{}}$ and 2.29×${10}^{-18\mathrm{}}$ ${\mathrm{cm}}^2$, respectively. Using the values of the electron-loss cross sections ${\sigma }_l$ for hydrogen atoms in hydrogen gas recently measured in this laboratory, the ratio $\frac{{\sigma }_l}{{\sigma }_c}$ was derived from the results of the present measurements. Direct measurements of this ratio agreed with the values derived from the separate measurements of ${\sigma }_l$ and ${\sigma }_c$ to within 10 percent.