Experimental study of electron- and ion-beam properties on the BNL electron-beam ion source and comparison with theoretical models

The maximum achievable perveance of the electron beam in the ion trap region and in the electron collector of the BNL Test electron-beam ion source (EBIS) has been measured for different electron-beam currents. These perveances determine the maximum degree of electron-beam retardation in these areas, which limits for the first case the maximum capacity of the ion trap, and for the second case the minimum dissipated power on the electron collector, for a given electron current. The results are compared with the results of optical simulations of the electron beam. In another set of experiments, data on Test EBIS ionization efficiency for different experimental conditions were obtained. These results are presented and compared with calculations based on stepwise ionization assuming 100% ion confinement in the trap. Finally, a series of experimentally measured longitudinal-energy spectra of the extracted ion beam are presented, and will be compared with the calculated energy spread.