FIELD: physics.
SUBSTANCE: quadrupole mass spectrometre has an ion source, a quadrupole mass analyser which includes four field-forming electrodes in form of circular and hyperbolic cylinders lying in parallel and symmetrically about the central axis of the analyser, and an ion collector. Each of the field-forming electrodes of the analyser has a through slotted opening on the side of its input, parallel to the axis of the analyser and lying in its plane of symmetry. The beginning of each of the openings lies at a distance of (0.5-4.0)r0 from the input faces of the analyser. The length of the opening along the axis inside the analyser is equal to (2.0-5.0)r0 and the width of the opening is equal to (0.2-0.8)r0, where r0 is minimum distance from the axis of the mass spectrometre to each of the said field-forming electrodes of the analyser.
EFFECT: prevention of formation of semiconducting films and stray potential on electrodes of the mass analyser and therefore prevention of deterioration of analytical characteristics of the mass spectrometre with time.
2 cl, 6 dwg
