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US 10,312,068 B2Granted
Charged particle detector
AssigneeHamamatsu Photonics K.K.
InventorsMotohiro Suyama, Hiroshi Kobayashi, Shinya Hattori
Life of this patent
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Abstract
A charged particle detector according to the embodiment is provided with an MCP and a PD arranged with a focus electrode interposed therebetween in order to improve a response characteristic as compared to a conventional one in a configuration in which the MCP having a bias angle and the PD are combined. The MCP includes a plurality of through holes each inclined by a bias angle θ and the PD is eccentrically arranged such that a center of an electron incident surface deviates by a predetermined distance in a bias angle direction S3 with respect to a central axis AX1 of the MCP.
Claims18
A charged particle detector comprising:
- a microchannel plate having:
- an input surface on which charged particles are incident;
- an output surface from which secondary electrons are emitted;
- and a plurality of through holes each communicating the input surface with the output surface and having a secondary electron emission surface on an inner wall thereof, the plurality of through holes arranged such that a central axis of each is inclined at least by a bias angle defined by an acute angle with respect to the output surface;
- an electron impact diode arranged so as to face the microchannel plate and having an electron incident surface whose area is smaller than an area of an effective region of the microchannel plate;
- and
- a focus electrode provided between the microchannel plate and the electron impact diode, the focus electrode having a shape to continuously surround trajectories of the secondary electrons directed from the microchannel plate to the electron impact diode,
- wherein, where a bias angle direction is, on a reference plane coincident with the electron incident surface, defined as a direction from an intersection between a reference axis and the reference plane to an intersection between a central axis of a reference through hole and the reference plane, the reference axis passing through a center of an opening coincident with the output surface out of openings of the reference through hole and orthogonal to the output surface, the reference through hole selected from the plurality of through holes,
- the electron impact diode is eccentrically arranged such that, with respect to an intersection between a central axis of the microchannel plate and the reference plane, a center of the electron incident surface deviates by a predetermined distance in the bias angle direction, the central axis of the microchannel plate being an axis passing through a center of the effective region and orthogonal to the output surface.
6 more elements
A charged particle detector comprising:
- a microchannel plate having:
- an input surface on which charged particles are incident;
- an output surface from which secondary electrons are emitted;
- and a plurality of through holes each communicating the input surface with the output surface and having a secondary electron emission surface on an inner wall thereof, the plurality of through holes arranged such that a central axis of each is inclined at least by a bias angle defined by an acute angle with respect to the output surface;
- an electron impact diode arranged so as to face the microchannel plate and having an electron incident surface whose area is smaller than an area of an effective region of the microchannel plate;
- and
- a focus electrode provided between the microchannel plate and the electron impact diode, the focus electrode having:
- a first opening located on a side of the microchannel plate;
- a second opening located on a side of the electron impact diode;
- and a shape to continuously surround trajectories of the secondary electrons directed from the microchannel plate to the electron impact diode,
- wherein, where a bias angle direction is, on a reference plane coincident with the electron incident surface, defined as a direction from an intersection between a reference axis and the reference plane to an intersection between a central axis of a reference through hole and the reference plane, the reference axis passing through a center of an opening coincident with the output surface out of openings of the reference through hole and orthogonal to the output surface, the reference through hole selected from the plurality of through holes,
- at least a part of the focus electrode is eccentrically arranged such that, with respect to an intersection between a central axis of the microchannel plate and the reference plane, a center of the second opening deviates by a predetermined distance in the bias angle direction, the central axis of the microchannel plate being an axis passing through a center of the effective region and orthogonal to the output surface.
9 more elements
Dependencies are inferred from the claim text.