Abstract: An ion pump having emissions containment. The ion pump includes an anode constructed from a plurality of tubes and a cathode constructed from plates positioned on opposite sides of the anode and positioned apart from the anode. The anode and cathode are positioned within a gastight housing having a gas inlet. A blocking shield assembly is provided within the line of sight between the gas inlet and the cathode. The blocking shield assembly is also provided within the line of sight between the gas inlet and any surface within the ion pump that itself is within the line of sight of the cathode. The blocking shield assembly prevents photons and neutral particles from being emitted from the ion pump.