Higherhyphen;Resolution Study of the Electronhyphen;Impact Spectrum of Helium

摘要

An electron source is described that provides, by means of an electrostatic velocity analyzer, for velocity selection on an electron beam before scattering. The energy width of the electron beam is sufficiently reduced to resolve the transitions to the 51Pand 61Pstates in helium. These states are separated by 0.17 V. Relative oscillator strengths for two additional members of the Rydberg series 11Srarr;m1Phave been determined by study of the zero angle electron scattering.