Electron-ion collision experiment using EBIS/EBIT

In EBIS (electron beam ion source) and EBIT (electron beam ion trap) which is its variation developed recently, by the spatial charge potential that the very high density electron flow converged with a strong magnetic field makes, the ions formed radially are confined, and by electrostatic field potential, axial ions are confined, by this means, it is attempted to obtain the multi-charge ions through the step by step ionization by the collision with high energy electrons many times. The large difference between both is whereas ionization occurs along the drift tube arranged in about 1 m in EBIS, in EBIT, ions are trapped in a short region of 1 - 2 cm. In order to make relatively heavy ions, ions must be confined for a considerably long time, and ultrahigh vacuum is required for an ion source. Ions are heated with the progress of ionization, and the confinement for a long time becomes difficult, accordingly, heavy ions are cooled by introducing light, low charge ions. The experiment using the ion beam of EBIS/EBIT is reviewed. The observation of the ion beam taken out from an ion source and the direct observation of ions inside an ion source are described. (K.I.)