A new detector for state analysis of multicharged ions, excited in high Rydberg states, at kinetic energies of the order of keV is described. It is composed of a field-ionizing lens system (FILS), associated with two electrostatic spectrometers; the first one, in front of the FILS, selects theq-times charged excited ions of interest, and the second one, behind the FILS, analyzes the(q+1)-times charged ions resulting from field ionization according to their kinetic energy. The principle of the FILS is to generate a linearly increasing electric field, colinear with the excited ion beam, that the excited multicharged ions experience until they are field ionized. This detector has been successfully used to detect for the first time the distributions of very high Rydbergnstates in the domainn=67–100produced inKr7+*(n)ions by electron capture intoKr8+from laser-excitedRb*(nip)atoms. ©1997 American Institute of Physics.