US 10,707,066 B2Granted

Quadrupole mass filter and quadrupole mass spectrometrometer

AssigneeShimadzu Corporation

InventorsShinji Miyauchi, Hiroko Ueda, Yoshihiro Ueno

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Abstract

Four main rod electrodes included in a main electrode section are disposed in a rotationally symmetric manner around an ion optical axis. Among four pre-rod electrodes included in a pre-electrode section disposed in front of the main electrode section, two are in contact with a circle of a radius r0, whereas the other two are disposed to be in contact with a circle of a radius R0 larger than r0, resulting in rotational asymmetry around the ion optical axis. Accordingly, a shape of acceptance on an x-y plane regarding positions of ions in the pre-electrode section becomes elliptical. This allows the shape of the acceptance to become gradually flat as the ions travel along the ion optical axis, reducing a mismatch between emittance of incoming ions and the acceptance on a receiving side, and relieving ion loss during ion introduction.

Claims4

Dependent claims

A quadrupole mass filter comprising:

a) a main electrode section including four main rod electrodes disposed to surround a central axis;
b) a pre-electrode section including pre-rod electrodes shorter than the main rod electrodes, the pre-rod electrodes being disposed in front of each of the main rod electrodes of the main electrode section along the central axis;
c) a first voltage application unit configured to apply, to each of the main rod electrodes, a voltage obtained by adding a direct current voltage and a radio-frequency voltage according to a mass-to-charge ratio of ions that are allowed to pass;
and
d) a second voltage application unit configured to apply, to each of the pre-rod electrodes, a radio-frequency voltage identical to the radio-frequency voltage in frequency,
wherein in the pre-electrode section, first two of the pre-rod electrodes positioned so as to sandwich the central axis and second two of the pre-rod electrodes adjacent to the first two of the pre-rod electrodes around the central axis are disposed at positions where radii of inscribed circles centered on the central axis differ.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/780,932Filed 2 Dec 2015
Published: US 2019/0051508 A114 Feb 2019
Granted: 7 Jul 2020
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H01J 49/4225
Two-dimensional RF ion traps: multipole linear ion traps, e.g. quadrupoles, hexapoles
H01J 49/065
Ion guides: having stacked electrodes, e.g. ring stack, plate stack
H01J 49/401
Time-of-flight spectrometers: characterised by orthogonal acceleration, e.g. focusing or selecting the ions, pusher electrode
H01J 49/4215
Mass filters, i.e. deviating unwanted ions without trapping: quadrupole mass filters