TOTAL SCATTERING CROSS-SECTIONS AND INTERATOMIC POTENTIALS FOR NEUTRAL HYDROGEN AND HELIUM ON SOME NOBLE GASSES (NEUTRAL HYDROGEN ON HELIUM; NEUTRAL DEUTERIUM ON HELIUM, NEON, ARGON, AND KRYPTON; AND NEUTRAL HELIUM ON HELIUM, ARGON, AND KRYPTON)

Abstract

This thesis presents measurements of the scattering cross-section in the energy range of (DBLTURN) 30eV to 1400eV for H('0) on He; D('0) on He, Ne, Ar, and Kr; and He('0) on He, Ar, and Kr. The cross-sections are determined by using the charge exchange efflux from the PLT tokamak as a source of H('0), D('0), or He('0). These neutrals pass through a gas-filled scattering cell and are detected by a time-of-flight spectrometer. The cross-section for scattering greater than the effective angle of the apparatus is found by measuring the energy-dependent attenuation of H('0), D('0), or He('0) as a function of pressure in the scattering cell. (For example, the scattering cross-section for D('0) on He at 100 (+OR-) 5eV is 2.53 (+OR-) 0.24 x 10('-16) cm('2). The effective angle for this pair is 1.12(DEGREES).) The interaction potential, V(r), in the form V(r) = K/r('8), is extracted from the data. The potentials are valid in the repulsive wall region: generally 0.5 (ANGSTROM) to 2.0 (ANGSTROM).