Spectrograph time of flight system for low energy neutral particles
AssigneeThe Johns Hopkins University
InventorStefano A. Livi
Life of this patent
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Abstract
A mass spectrometer is provided for identifying mass and velocity distributions in a continuous ion beam is configured with a circular dispersive system creating a rotating electromagnetic field, which is capable of deflecting the ion beam from an initial direction, and a circular position-sensitive detector intercepting the deflected ion beam and providing information from which the ion mass-per-charge ratio is determined
Claims19
A mass spectrometer for identifying mass and velocity distributions in a continuous ion beam comprising:
- a guide assembly operative to direct the continuous ion beam along a first axis;
- a plurality of curved electrodes extending along an arc of a circle and traversed by the continuous ion beam to create a rotating electric field impressed upon and selectively deflecting the continuous ion beam along a second axis extending transversely to the first axis;
- and
- a position-sensitive detector operative to detect a position and time of arrival of individual ions in the continuous ion beam, whereby the detected position of each individual ion in the continuous ion beam provides information from which the ion mass-per-charge ratio is determined.
A method for determining an ion mass-per-charge ratio comprises the steps of:
- (a) directing a ion beam along an axis extending in an initial direction;
- (b) providing a plurality of curved electrodes extending along an arc of a circle to define a dispersing region therebetween and creating a rotating electric field impressed upon selectively applying a dispersing voltage at a desired frequency to the plurality of curved electrodes;
- (c) electromagnetically deflecting the ion beam from the axis along a second axis transverse to the first axis while dispersing the ion beam;
- and (d) detecting with a circular position-sensitive detector intercepting the ion beam characteristics of individual ions of the ion beam.
A mass spectrometer for identifying mass and velocity distributions in a continuous ion beam comprising:
- a guide assembly operative to direct the continuous ion beam along a first axis;
- a plurality of curved electrodes extending along an arc of a circle and traversed by the continuous ion beam to create a rotating electric field impressed upon and selectively deflecting the continuous ion beam along a second axis extending transversely to the first axis;
- a circular position-sensitive detector operative to detect a position and time of arrival of individual ions in the continuous ion beam, whereby the detected position of each individual ion in the continuous ion beam provides information from which the ion mass-per-charge ratio is determined;
- and,
- a reflectron spaced axially between the plurality of curved electrodes and the position-sensitive detector and operative to reverse an axial direction of the continuous ion beam towards the circular position-sensitive detector configured to surround the plurality of curved electrodes.
A mass spectrometer for identifying mass and velocity distributions in a continuous ion beam comprising:
- a guide assembly operative to direct the continuous ion beam along a first axis;
- a dispersive system traversed by the continuous ion beam and operative to create a rotating electric field impressed upon and selectively deflecting the continuous ion beam along a second axis extending transversely to the first axis;
- and, a circular position-sensitive detector operative to detect a position and time of arrival of individual ions in the continuous ion beam, whereby the detected position of each individual ion in the continuous ion beam provides information from which the ion mass-per-charge ratio is determined.
Dependencies are inferred from the claim text.