Electron loss and collisional destruction of fast He+(2S) ions and application to a polarized3He ion source

A modulated beam technique has been used to determine cross sections for one-electron loss sigma 1*2 and total cross sections sigma D for collisional destruction of 18-50 keV 3 He + (2S) metastable ions in H 2 , He, Ar, N 2 and O 2 . Cross sections sigma 1*2 are shown to be roughly 100 times larger than the corresponding one-electron loss cross sections for ground state He + ions. Total collisional destruction cross sections sigma D , which are very large ( approximately 10 -15 cm 2 ) and not greatly energy dependent, indicate that electron loss is not the dominant destruction mechanism in the present energy range. The results are shown to be consistent with the requirements of a recently proposed source of polarized 3 He ions. Data relevant to the optimization of such a source are presented.