Energy Nitrogen Ion Research Articles

Elastic Scattering ofN14byBe9

Nitrogen-beryllium elastic scattering was measured over an angular range from 32 to 144 deg in the center-of-mass system with an angular resolution of about one degree. The mean energy of the incident nitrogen ions was 27.3 Mev. To distinguish elastic scattering from other events, both the scattered and the recoil particles were detected in coincidence by thin CsI(Tl) scintillation counters. The elastic scattering differential cross section is 550 mb/sterad at 32 deg c.m. It decreases monotonically and more rapidly than ${csc}^{4}(\frac{\ensuremath{\theta}}{2})$ to a shallow minimum of about 5 mb/sterad at 106 deg c.m., rises slightly, and then falls to about 2.5 mb/sterad at 144 deg c.m., the largest angle measured. The data are compared to the predictions of a sharp-cutoff model for elastic scattering, but no agreement is found between this theory and the experimental results.

The Energy Loss of Hydrogen, Helium, Nitrogen, and Neon Ions in Gases

The rate of loss of energy of protons, deuterons, helium, nitrogen, and neon ions in the energy range of 150 to 450 kev has been measured in the gases hydrogen, helium, air, and argon. The ions were sent through a differentially pumped gas system and the energy loss in the forward direction due to the gas was determined with an electrostatic analyzer.The results for protons agree with recent measurements at the California Institute of Technology. At the same energy, the stopping cross sections are roughly the same for neon and helium ions. The stopping power for nitrogen ions is greater than that for neon ions of the same energy by a factor ranging from 1.3 to 1.9, illustrating the importance of external electron configurations in determining stopping powers in our energy region. With the exception of hydrogen gas, the cross sections for the heavier ions follow a power law. The dependence ranges from ${E}^{0.33}$ to ${E}^{0.59}$, depending on the gas and ion, with several of the curves following an ${E}^{\frac{1}{2}}$ power law.