A method and apparatus for extracting for quantitative analysis ions of selected atomic components of a sample (14). A lens system (46, 50, 54) is configured to provide a slowly diminishing field region for a volume containing the selected atomic components, enabling accurate energy analysis of ions generated in the slowly diminishing field region. The lens system (46, 50, 54) also enables focusing on a sample (14) of a charged particle beam, such as an ion beam (18), along a path length perpendicular to the sample and extraction of the charged particles (88) along a path length also perpendicular to the sample (14). Improvement of signal to noise ratio is achieved by laser excitation of ions to selected autoionization states before carrying out quantitative analysis. Accurate energy analysis of energetic charged particles is assured by using a preselected resistive thick film configuration disposed on an insulator substrate for generating predetermined electric field boundary conditions to achieve for analysis the required field potential. The spectrometer also is applicable in the fields of SIMS, ISS and electron spectroscopy.