Abstract: The invention relates to an ionization chamber (10) comprising an inner spherical electrode (2), an outer spherical electrode (4), a space between the inner spherical electrode and the outer spherical electrode, and a resistive hollow body (3) provided in the said space, wherein electrical connections to the inner spherical electrode and electrical connection to the top of the resistive hollow body (3) are electrostatically shielded by that same resistive hollow body having a continuously varied local resistance along its axis. The invention further relates to a method of manufacturing an ionization chamber.