The present embodiment relates to an ion detector provided with a structure for suppressing degradation over time in an electron multiplication mechanism in the ion detector. The ion detector includes a dynode unit, serving as an electron multiplication mechanism, which multiplies secondary electrons which are emitted in response to incidence of ions, and a semiconductor detector having an electron multiplication function. Further, a focus electrode having an opening that allows passage of secondary electrons is disposed on a trajectory of secondary electrons which are directed from the dynode unit toward the semiconductor detector, and the focus electrode functions to guide secondary electrons from the dynode unit onto an electron incidence surface of the semiconductor detector.

The present embodiment relates to an ion detector provided with a structure for suppressing degradation over time in an electron multiplication mechanism in the ion detector. The ion detector includes a dynode unit, serving as an electron multiplication mechanism, which multiplies secondary electrons which are emitted in response to incidence of ions, and a semiconductor detector having an electron multiplication function. Further, a focus electrode having an opening that allows passage of secondary electrons is disposed on a trajectory of secondary electrons which are directed from the dynode unit toward the semiconductor detector, and the focus electrode functions to guide secondary electrons from the dynode unit onto an electron incidence surface of the semiconductor detector.

Disclosed herein is a photomultiplier comprising: an electron ejector; a detector; a substrate; and a first electrode in the substrate; a second electrode in the substrate; a third electrode in the substrate; wherein each of the first, second and third electrodes comprises a flat or curved surface at an angle to a normal direction of the substrate; wherein each of the first, second and third electrodes comprises a first end and a second end, the first end being closer to the electron ejector than the second end; wherein the first, second and third electrodes are spatially arranged such that the second ends of the first, second and third electrode are on a same plane, or such that a plane the second ends of the first and third electrodes are on crosses the second electrode.

Disclosed herein is a photomultiplier comprising: an electron ejector; a detector; a substrate; and a first electrode in the substrate; a second electrode in the substrate; a third electrode in the substrate; wherein each of the first, second and third electrodes comprises a flat or curved surface at an angle to a normal direction of the substrate; wherein each of the first, second and third electrodes comprises a first end and a second end, the first end being closer to the electron ejector than the second end; wherein the first, second and third electrodes are spatially arranged such that the second ends of the first, second and third electrode are on a same plane, or such that a plane the second ends of the first and third electrodes are on crosses the second electrode.

A magnetic photomultiplier tube (PMT) system, comprising a PMT. The PMT comprising a photocathode for converting an impinging photon to a photoelectron, an anode, and at least two or a series of oppositely facing pairs of dynodes, wherein each pair is spaced apart from an adjacent pair, a first electric field being generated intermediate at least one pair of oppositely facing dynodes and a second electric field generated intermediate at least one adjacent pairs of dynodes. The PMT system comprises a magnetic field generated by a magnetic system, the PMT being positioned within the magnetic field.

A magnetic photomultiplier tube (PMT) system, comprising a PMT. The PMT comprising a photocathode for converting an impinging photon to a photoelectron, an anode, and at least two or a series of oppositely facing pairs of dynodes, wherein each pair is spaced apart from an adjacent pair, a first electric field being generated intermediate at least one pair of oppositely facing dynodes and a second electric field generated intermediate at least one adjacent pairs of dynodes. The PMT system comprises a magnetic field generated by a magnetic system, the PMT being positioned within the magnetic field.

A secondary electron multiplier includes: a conversion dynode for emitting a secondary electron in response to an incident ion; a plurality of dynodes configured to have multi-stages from second to final stages for receiving the secondary electron; and a first voltage applying device for applying a first negative voltage to the conversion dynode and sequentially dividing the first negative voltage to apply to each of the second-stage and subsequent dynodes, wherein the secondary electron multiplier is configured to sequentially multiply the emitted secondary electron by the second-stage and subsequent dynodes. In the secondary electron multiplier, any of the second-stage and subsequent dynodes have a second voltage applying device for applying a second negative voltage. The secondary electron multiplier has an improved ion detection efficiency without a large reduction of a usable period thereof, thereby enhancing the sensitivity of a mass spectrometer.

Certain embodiments described herein are directed to ion detectors and systems. In some examples, the ion detector can include a plurality of dynodes, in which one or more of the dynodes are coupled to an electrometer. In other configurations, each dynode can be coupled to a respective electrometer. Methods using the ion detectors are also described.

Certain embodiments described herein are directed to ion detectors and systems. In some examples, the ion detector can include a plurality of dynodes, in which one or more of the dynodes are coupled to an electrometer. In other configurations, each dynode can be coupled to a respective electrometer. Methods using the ion detectors are also described.

Disclosed herein is a photomultiplier tube (PMT) comprising: an electron ejector configured for emitting primary electrons in response to an incident photon; a detector configured for collecting electrons and providing an output signal representative of the incident photon; and a series of electrodes between the electron ejector and the detector, wherein each of the electrodes is configured for emitting secondary electrons in response to incident electrons, and each of the electrodes includes a bi-metal arc-shaped sheet.