J. Phys. Colloques
Volume 48, Numéro C6, Novembre 198734th International Field Emission Symposium / 34ème Symposium International d'Emission de Champ
|Page(s)||C6-195 - C6-200|
J. Phys. Colloques 48 (1987) C6-195-C6-200
EMISSION CHARACTERISTICS OF LIQUID Pr ION SOURCESS. Papadopoulos1, 2
1 AT&T Bell Laboratories, Murray Hill, New Jersey, U.S.A.
2 Department of Engineering Science, Oxford University, Oxford, United Kingdom
We have made liquid Pr ion sources and have studied their main emission characteristics. From the study of the mass spectrum at different source currents it was found that the dominant emitted species are Pr2+ and Pr+. Clusters Pr+n with n=2-13 comprising <1% of the beam are also present. The angular distribution of all species studied is a decreasing function of angle of emission at all source currents and the energy spread increases in general with current, although not in a simple manner. With the exception of Pr2+ whose energy spread is angle-independent, the energy spread of all other species decreases with angle of emission. The shape of the energy spectra of the main species has also been studied as a function of current and angle of emission. All energy spectra are single peaked apart from those of Pr+ and Pr+3 ions. With regard to changes in the energy spectrum the behaviour of Pr+ ions is quite complicated. An extensive discussion is presented in an attempt to explain some of the observations reported here.