Electron and charged particle detectors

Abstract

An electron detector and a charged particle detector are provided that can improve the quality of an electrical signal. [Solution] The electron detector 5 comprises an electron detection unit 53 including a first electrode 52, a resin sheet 59 arranged on one side of the first electrode 52 in the Z direction, a second electrode 54 facing the first electrode 52 via the resin sheet 59, an insulating substrate 61 arranged on one side of the second electrode 54 in the Z direction and supporting the electron detection unit 53, the resin sheet 59 and the second electrode 54, an output unit 55 arranged on one side of the insulating substrate 61 in the Z direction, electrically connected to the second electrode 54 and outputting an electrical signal, and a support unit 62 supporting the output unit 55 so that the output unit 55 and the second electrode 54 face each other via the insulating substrate 61 and so that a space SP1 is formed between the output unit 55 and the insulating substrate 61.

Description

[Technical Field]

[0001] The present invention relates to electron and charged particle detectors. [Background technology]

[0002] As a charged particle detector applicable to mass spectrometry and the like, Patent Document 1 describes an ion detector including a microchannel plate (hereinafter referred to as "MCP") that emits electrons in response to incident ions, an anode electrode that detects the electrons emitted from the MCP, a coaxial cable including an inner conductor electrically connected to the anode electrode, and a ground electrode electrically connected to the outer conductor of the coaxial cable. In the ion detector described in Patent Document 1, the anode electrode is configured by disposing a dielectric member between the collector electrode and a conductive plate. This allows the collector electrode and the conductive plate to function as a capacitor, removing a DC component from the electrical signal output via the coaxial cable. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-273867 Summary of the Invention [Problem to be solved by the invention]

[0004] In the ion detector described in Patent Document 1, the conductive plate included in the anode electrode, which serves as the electron detector, and the ground electrode face each other, which generates parasitic capacitance between the anode electrode and the ground electrode, which can result in ringing in the electrical signal output via the coaxial cable.When the ion detector is applied to a mass spectrometer, if ringing occurs in the electrical signal output from the ion detector, the accuracy of mass analysis can be reduced.

[0005] An object of the present invention is to provide an electron detector and a charged particle detector that can improve the quality of an electric signal. [Means for solving the problem]

[0006] The electron detector of the present invention is [1] "an electron detector comprising: an electron detection unit including a first electrode and detecting incident electrons; a resin sheet arranged on one side of the first electrode in a first direction; a second electrode arranged on the one side of the resin sheet in the first direction and facing the first electrode via the resin sheet; an insulating substrate arranged on the one side of the second electrode in the first direction and supporting the electron detection unit, the resin sheet, and the second electrode; an output unit arranged on the one side of the insulating substrate in the first direction, electrically connected to the second electrode, and outputting the electrical signal; and a support unit supporting the output unit so that the output unit and the second electrode face each other via the insulating substrate and so that a space is formed between the output unit and the insulating substrate."

[0007] In the electron detector described in [1] above, the first electrode and the second electrode, which face each other via the resin sheet, function as, for example, a capacitor that removes DC components from the electrical signal detected by the electron detection unit. As a result, the electrical signal from which the DC components have been removed is output from the output unit. Furthermore, a resin sheet is used for the capacitor, and the electron detection unit, the resin sheet, and the second electrode are supported by an insulating substrate. This ensures sufficient voltage resistance for the capacitor and sufficient mechanical strength for the electron detector. Furthermore, the output unit is supported by a support so as to form a space between the output unit and the insulating substrate. This reduces parasitic capacitance generated between the output unit and the second electrode, suppressing ringing in the electrical signal due to the parasitic capacitance. As a result, the electron detector can improve the quality of the electrical signal.

[0008] The electron detector of the present invention may be [2] "the electron detector according to the above [1], in which the width of the space in the first direction is greater than 1 / 3 times the thickness of the insulating substrate." According to the electron detector according to [2], the parasitic capacitance generated between the output section and the second electrode can be sufficiently reduced.

[0009] The electron detector of the present invention may be [3] "the charged particle detector according to the above [1] or [2], wherein the support part is fixed to the insulating substrate." According to the electron detector according to [3], the output part can be stably supported at a desired position relative to the insulating substrate.

[0010] The electron detector of the present invention may be [4] "the electron detector according to any one of [1] to [3] above, further comprising: a third electrode disposed on the other side of the resin sheet in the first direction and spaced from the first electrode in a second direction intersecting the first direction; and a fourth electrode disposed on the one side of the resin sheet in the first direction and spaced from the second electrode in the second direction, facing the third electrode via the resin sheet; wherein the output section includes an internal conductor electrically connected to one of the second electrode and the fourth electrode; and an external conductor surrounding the internal conductor while being electrically insulated from the internal conductor and electrically connected to the other of the second electrode and the fourth electrode." According to the electron detector described in [4], just as the first electrode and the second electrode facing each other via the resin sheet function as a capacitor, the third electrode and the fourth electrode facing each other via the resin sheet also function as a capacitor. One of these capacitors functions as a capacitor that removes DC components from the electrical signal detected by the electron detection section. As a result, the electrical signal from which the DC component has been removed is output from the internal conductor of the output section via the second or fourth electrode. Meanwhile, the other of these capacitors functions as a return capacitor located on the return path through which the return current from the external conductor flows. This makes it possible to suppress deterioration of the electrical signal waveform due to ringing, etc.

[0011] The electron detector of the present invention may be [5] "the electron detector according to the above [4], further comprising a spring connector, wherein the insulating substrate includes wiring electrically connected to the second electrode or the fourth electrode, and the spring connector is disposed between the wiring and the internal conductor or the external conductor." According to the electron detector according to [5], even if a space is formed between the output section and the insulating substrate, electrical connection between the wiring and the internal conductor or the external conductor can be reliably achieved.

[0012] The electron detector of the present invention may be [6] "the electron detector according to the above [4], further comprising a spring connector, wherein the insulating substrate includes a first wiring electrically connected to the second electrode or the fourth electrode, the support portion includes a second wiring electrically connected to the internal conductor or the external conductor, and the spring connector is disposed between the first wiring and the second wiring." According to the electron detector according to [6], even if a space is formed between the output portion and the insulating substrate, electrical connection between the first wiring and the second wiring can be reliably achieved.

[0013] The electron detector of the present invention may be [7] "the electron detector according to any one of the above [4] to [6], further comprising a resistor electrically connected between the other of the second electrode and the fourth electrode and the external conductor." According to the electron detector according to [7], the resistor absorbs high-frequency components of the electric signal, so that ringing occurring in the electric signal can be more reliably suppressed.

[0014] The electron detector of the present invention may be [8] "the electron detector according to any one of the above [1] to [7], wherein the electron detecting section further includes an avalanche diode electrically connected to the first electrode, and the avalanche diode detects the electrons." According to the electron detector according to [8], electrons can be detected with high sensitivity by the avalanche effect of the avalanche diode.

[0015] The electron detector of the present invention may be [9] "the electron detector according to any one of the above [1] to [7], wherein the first electrode detects the electrons." According to the electron detector according to [9], the first electrode serves as both an electrode for electron detection and an electrode for a coupling capacitor, which simplifies the configuration of the electron detection unit.

[0016] The electron detector of the present invention may be

[10] "the electron detector according to any one of the above [1] to

[11] , further comprising an insulating layer covering the second electrode on the one side in the first direction with respect to the resin sheet and covering the first electrode on the other side in the first direction with respect to the resin sheet." According to the electron detector according to

[10] , deterioration of the first electrode and the second electrode can be suppressed.

[0017] The charged particle detector of the present invention may be

[11] "a charged particle detector comprising the electron detector according to any one of [1] to

[10] above and an electron emitter that emits electrons in response to incidence of a charged particle." The charged particle detector according to

[11] can improve the quality of the electrical signal in the electron detector.

[0018] The charged particle detector of the present invention may be

[12] "the charged particle detector according to the above

[11] , wherein the electron emitter includes a microchannel plate." According to the charged particle detector according to

[12] , electrons emitted from the electron emitter are amplified as secondary electrons, so that the electrical signal output from the electron detector can be increased. Furthermore, secondary electrons can be emitted with a high amplification factor.

[0019] The charged particle detector of the present invention may be

[13] "the charged particle detector according to the above

[11] , wherein the electron emitter includes a plurality of dynodes." According to the charged particle detector according to

[13] , electrons emitted from the electron emitter are amplified as secondary electrons, so that the electrical signal output from the electron detector can be increased. Furthermore, secondary electrons can be emitted with a high amplification factor. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide an electron detector and a charged particle detector that can improve the quality of an electric signal. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a diagram illustrating a circuit configuration of a charged particle detector according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the electron detector shown in FIG. [Figure 3] FIG. 2 is a front view of the electron detector shown in FIG. 1. [Figure 4] FIG. 2 is a rear view of the electron detector shown in FIG. 1. [Figure 5] FIG. 10 is a cross-sectional view of an electron detector according to a first modified example. [Figure 6] 6 is a graph showing an example of the behavior of an electrical signal output from the electron detector shown in FIG. 5. [Figure 7] FIG. 10 is a cross-sectional view of an electron detector according to a second modified example. [Figure 8] FIG. 10 is a cross-sectional view of an electron detector according to a third modified example. [Figure 9] FIG. 10 is a cross-sectional view of an electron detector according to a fourth modified example. [Figure 10] FIG. 10 is a cross-sectional view of a modified charged particle detector. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and duplicated explanations will be omitted. [Charged particle detector configuration]

[0023] The electron detector of the present invention outputs incident electrons as an electron signal. The electron detector of the present invention is applied to, for example, a charged particle detector, a photomultiplier tube, or a hybrid photodetector. In this embodiment, an example in which the electron detector is applied to a charged particle detector will be described. As shown in FIG. 1 , the charged particle detector 1 includes an electron emitter 2, an acceleration electrode 3, a focus electrode 4, and an electron detector 5. In the charged particle detector 1, the electron emitter 2, the acceleration electrode 3, the focus electrode 4, and the electron detection section 53 of the electron detector 5 are arranged in this order. The charged particle detector 1 is, for example, an ion detector that detects ions of both polarities. The charged particle detector 1 is applied to, for example, a mass spectrometer. Note that the charged particle detector 1 may also be one that detects charged particles other than ions (e.g., electrons, etc.).

[0024] The electron emitter 2 emits electrons in response to the incidence of ions IN. The polarity of the ions IN may be negative or positive. The electron emitter 2 includes a microchannel plate (hereinafter referred to as "MCP") 21. The MCP 21 is an electron multiplier element that emits electrons in response to the incidence of ions IN. The MCP 21 has an input surface 21a and an output surface 21b. The side surfaces of the MCP 21 are surrounded by an insulating ring made of an insulating material. When ions IN are incident on the input surface 21a, the MCP 21 generates electrons in response to the incidence of the ions IN, multiplies the electrons, and emits them from the output surface 21b. In other words, the MCP 21 also functions as an electron multiplier. The MCP 21 has a plurality of through-holes (channels) formed therein, each extending along the thickness direction (the direction in which the input surface 21a and the output surface 21b face each other). Electrodes are formed on the outer edge portions of the input surface 21a and the output surface 21b, respectively. The electron emitter 2 may independently include an electron emitter that emits electrons in response to incident ions IN and an electron multiplier that multiplies and emits the electrons. For example, the electron emitter 2 may include an ion-electron converter provided in front of the MCP 21 as the electron emitter, and the MCP 21 as the electron multiplier.

[0025] The acceleration electrode 3 accelerates the electrons emitted from the output surface 21b of the MCP 21. The focus electrode 4 focuses the electrons accelerated by the acceleration electrode 3 onto the electron detection portion 53 of the electron detector 5.

[0026] The electron detector 5 outputs, as an electric signal, the electrons emitted from the MCP 21. The electron detector 5 has an electron detection section 53 including an avalanche diode (hereinafter referred to as "AD") 51 and a first electrode 52, a second electrode 54, an output section 55, a signal output terminal 56, a third electrode 57, and a fourth electrode 58.

[0027] AD51 receives electrons focused by focus electrode 4 and outputs them as an electrical signal. An anode electrode 511 of AD51 faces focus electrode 4. That is, electrons focused by focus electrode 4 are incident on anode electrode 511.

[0028] The first electrode 52 is electrically connected to the cathode electrode 512 of the AD 51. The first electrode 52 and the second electrode 54 form a signal capacitor C1. The signal capacitor C1 functions as a coupling capacitor that removes DC components from the electrical signal output from the AD 51.

[0029] The output unit 55 is electrically connected to the second electrode 54 and outputs an electrical signal toward the signal output terminal 56. The output unit 55 includes an internal conductor 551 and an external conductor 552. The internal conductor 551 is electrically connected to the second electrode 54. The external conductor 552 surrounds the internal conductor 551. A gap may be provided between the internal conductor 551 and the external conductor 552, or an insulating member may be disposed therebetween. The external conductor 552 is connected to a reference potential GND. The output unit 55 is, for example, an SMA connector. In this case, the internal conductor 551 is a signal line that transmits an electrical signal, and the external conductor 552 is an outer conductor that covers the signal line.

[0030] The third electrode 57 is electrically connected to the anode electrode 511 of the AD 51. The fourth electrode 58 is electrically connected to the reference potential GND and the external conductor 552. The third electrode 57 and the fourth electrode 58 are arranged on a return path formed from the external conductor 552 to the anode electrode 511, and form a return capacitor C2. By providing the return capacitor C2, deterioration of the waveform of the electrical signal due to ringing and the like is suppressed. Ringing is a high-frequency component that is superimposed on the electrical signal when the magnitude of the electrical signal changes, for example, when the electrical signal rises or falls.

[0031] A parasitic capacitance Cp may occur between the second electrode 54 and the external conductor 552. The parasitic capacitance Cp is a parasitic component that occurs when the second electrode 54 and the external conductor 552 face each other. The parasitic capacitance Cp may cause ringing in the electrical signal output from the signal output terminal 56. If, for example, a mass spectrometer is connected downstream of the electron detector 5 and ringing occurs in the electrical signal, the mass spectrometer may not be able to accurately read the magnitude of the electrical signal, which may affect the accuracy of mass analysis. For this reason, it is extremely important to minimize the parasitic capacitance Cp and suppress the effects of ringing.

[0032] The input surface 21a of the MCP 21 is electrically connected to a power supply 71 and is set to a potential Va (e.g., +10 kV or −10 kV). A power supply 72 applies a potential difference Vb (e.g., 0 V to 1 kV) between the input surface 21a and the output surface 21b. One end of a resistor Ra is electrically connected to a node between the cathode electrode 512 and the first electrode 52. A power supply 73 applies a potential difference Vc (e.g., 0 V to 6 kV) between the output surface 21b and the other end of the resistor Ra. The potential difference (voltage) Vc is divided by a resistor Rb (e.g., 40 MΩ), a resistor Rc (e.g., 20 MΩ), and a Zener diode 74. The Zener diode 74 ensures a potential difference of 300 V between the resistor Rc and the resistor Ra. An acceleration electrode 3 is electrically connected to a node located between the resistors Ra and Rb. The focus electrode 4 is set to the same potential as the output surface 21b. A resistor Rd is electrically connected between the anode electrode 511 and a node between the resistor Rc and the Zener diode 74 .

[0033] When measuring negative ions IN, for example, +10 kV is applied as the potential Va. In this case, if the potential difference Vb becomes +1 kV and the potential difference Vc becomes +6 kV, the potential at the other end of the resistor Ra becomes +17 kV. When measuring positive ions IN, for example, -10 kV is applied as the potential Va. In this case, if the potential difference Vb becomes +1 kV and the potential difference Vc becomes +6 kV, the potential at the other end of the resistor Ra becomes -3 kV. In both measurements of negative ions IN and positive ions IN, the potential increases from the input surface 21 a of the MCP 21 toward the anode electrode 511 of the AD51. Furthermore, the potential applied to the cathode electrode 512 of the AD51 is greater than the potential applied to the anode electrode 511. Therefore, a reverse bias voltage is applied between the anode electrode 511 and the cathode electrode 512 of the AD51, and the AD51 operates in a floating state. [Electron detector configuration]

[0034] As shown in FIGS. 2, 3, and 4, the electron detector 5 further includes a resin sheet 59, an insulating substrate 61, a support portion 62, and an insulating layer 63. Hereinafter, the thickness direction of the insulating substrate 61 is referred to as the Z direction (first direction), a direction perpendicular to the Z direction is referred to as the X direction (second direction), and a direction perpendicular to the Z direction and the X direction is referred to as the Y direction. In the electron detector 5, the AD 51, the first electrode 52, the resin sheet 59, the second electrode 54, the insulating substrate 61, and the output portion 55 are arranged in this order in the Z direction. In the following description, "disposed on one side" means that each component is disposed on the opposite side of the AD 51 (the output portion 55 side) from the adjacent component on the AD 51 side. "disposed on the other side" means that each component is disposed on the opposite side of the output portion 55 (the AD 51 side) from the adjacent component on the output portion 55 side.

[0035] The AD 51 is disposed, for example, at a position where electrons emitted from the MCP 21 reach. The first electrode 52 is disposed on the opposite side of the AD 51 from the MCP 21 and is electrically connected to the AD 51. In the electron detector 5, the first electrode 52 is in contact with the cathode electrode 512 of the AD 51.

[0036] The resin sheet 59 is disposed on one side in the Z direction of the first electrode 52. The resin sheet 59 is in contact with the first electrode 52. The resin sheet 59 is made of a resin such as a liquid crystal polymer (LCP), a polyester film, a polyimide, or a polyamide. The second electrode 54 is disposed on one side in the Z direction of the resin sheet 59. The second electrode 54 is in contact with the resin sheet 59. The second electrode 54 faces the first electrode 52 with the resin sheet 59 interposed therebetween. The area of ​​the first electrode 52 and the area of ​​the second electrode 54 may be the same, and the outer edge of the first electrode 52 and the outer edge of the second electrode 54 may coincide when viewed from the Z direction.

[0037] The first electrode 52, the resin sheet 59, and the second electrode 54 constitute the signal capacitor C1. The first electrode 52 and the second electrode 54 are a pair of electrode plates of the signal capacitor C1, and the resin sheet 59 is the dielectric of the signal capacitor C1. The capacitance required for the signal capacitor C1 to function as a coupling capacitor is, for example, 50 pF or more. In addition, the resin sheet 59 is required to be able to withstand a high voltage with an absolute value of 10 kV or more. In light of the above, the thickness of the resin sheet 59 is preferably 25 μm or more and 200 μm or less, and the area of ​​each of the first electrode 52 and the second electrode 54 is preferably 5 mm × 5 mm or more and 30 mm × 30 mm or less.

[0038] The third electrode 57 is disposed on the other side in the Z direction with respect to the resin sheet 59. The third electrode 57 is spaced apart from the first electrode 52 in the X direction. When viewed from the Z direction, the third electrode 57 is aligned with the first electrode 52 in the X direction while being spaced apart from the first electrode 52. The third electrode 57 is in contact with the resin sheet 59. In the electron detector 5, the third electrode 57 is electrically connected to the anode electrode 511 via a wiring WR.

[0039] The fourth electrode 58 is disposed on one side in the Z direction with respect to the resin sheet 59. The fourth electrode 58 is spaced apart from the second electrode 54 in the X direction. When viewed from the Z direction, the fourth electrode 58 is spaced apart from the second electrode 54 and is aligned with the second electrode 54 in the X direction. The fourth electrode 58 is in contact with the resin sheet 59. The fourth electrode 58 faces the third electrode 57 with the resin sheet 59 interposed therebetween. The area of ​​the third electrode 57 and the area of ​​the fourth electrode 58 may be the same, and the outer edge of the third electrode 57 and the outer edge of the fourth electrode 58 may coincide when viewed from the Z direction.

[0040] The third electrode 57, resin sheet 59, and fourth electrode 58 constitute the return capacitor C2. The third electrode 57 and fourth electrode 58 are a pair of electrode plates of the return capacitor C2, and the resin sheet 59 is the dielectric of the return capacitor C2. In other words, the dielectric of the return capacitor C2 is the same as the dielectric of the signal capacitor C1. The capacitance of the return capacitor C2 is the same as that of the signal capacitor C1, for example, 50 pF or less. The thickness of the resin sheet 59 is preferably 25 μm or more and 200 μm or less, and the area of ​​each of the first electrode 52 and the second electrode 54 is preferably 5 mm × 5 mm or more and 30 mm × 30 mm or less.

[0041] The insulating substrate 61 is disposed on one side in the Z direction with respect to the second electrode 54 and the fourth electrode 58. The insulating substrate 61 supports the AD 51, the first electrode 52, the resin sheet 59, the second electrode 54, the third electrode 57, and the fourth electrode 58.

[0042] The insulating substrate 61 includes an insulating substrate body 613. The material of the insulating substrate body 613 is, for example, an insulating material such as FR-4 (Frequency Reduction Four). FR-4 is a composite material based on epoxy resin reinforced with glass fiber. The thickness of the insulating substrate body 613 is, for example, 0.5 mm to 3 mm. The signal capacitor C1 and the return capacitor C2 are sheet-like structures with a thickness of, for example, several hundred μm. Therefore, the insulating substrate 61 reinforces the first electrode 52, the resin sheet 59, and the second electrode 54, and also functions as a reinforcing plate that reinforces the third electrode 57, the resin sheet 59, and the fourth electrode 58.

[0043] The insulating substrate 61 further includes a wiring (first wiring) 611 and a wiring (first wiring) 612. The wiring 611 and the wiring 612 are wirings that pass through an insulating substrate main body 613. The wiring 611 is electrically connected to the second electrode 54. One end of the wiring 611 is physically connected to the second electrode 54, and the other end of the wiring 611 is exposed to one side in the Z direction with respect to the insulating substrate main body 613. In the electron detector 5, the other end of the wiring 611 forms an electrode pad 611a on the surface of the insulating substrate main body 613 opposite to the second electrode 54. The wiring 612 is electrically connected to the fourth electrode 58. One end of the wiring 612 is physically connected to the fourth electrode 58, and the other end of the wiring 612 is exposed to one side in the Z direction with respect to the insulating substrate main body 613. In the electron detector 5, the other end of the wiring 611 forms an electrode pad 612a on the surface of the insulating substrate body 613 opposite to the fourth electrode 58. When viewed from the Z direction, the electrode pad 612a is spaced apart from the electrode pad 611a and is aligned with the electrode pad 611a in the X direction.

[0044] The insulating substrate 61 has a circular shape when viewed from the Z direction, for example. For example, if the MCP 210 is circular, the circular insulating substrate 61 facilitates alignment between the MCP 210 and the AD 51 in the X and Y directions. The first electrode 52, the second electrode 54, the third electrode 57, and the fourth electrode 58 may have a circular shape to match the shape of the insulating substrate 61. However, the shapes of the insulating substrate 61 and each electrode are not limited to a circular shape and may be rectangular, elliptical, or polygonal. Furthermore, when viewed from the Z direction, the first electrode 52 and the third electrode 57 may be disposed with the center of the insulating substrate 61 sandwiched therebetween. That is, the first electrode 52 and the third electrode 57 may be disposed point-symmetrically with respect to each other with respect to the center of the insulating substrate 61. Similarly, when viewed from the Z direction, the second electrode 54 and the fourth electrode 58 may be disposed with the center of the insulating substrate 61 sandwiched therebetween. That is, the second electrode 54 and the fourth electrode 58 may be arranged point-symmetrically with respect to the center of the insulating substrate 61.

[0045] The support section 62 is disposed on one side in the Z direction with respect to the insulating substrate 61. The support section 62 is fixed to the insulating substrate 61. The output section 55 is disposed on one side in the Z direction with respect to the support section 62. Therefore, the insulating substrate 61, the support section 62, and the output section 55 are disposed in this order in the Z direction.

[0046] The support 62 supports the output section 55 so that the output section 55 and the second electrode 54 face each other via the insulating substrate 61 and so that a space SP1 is formed between the output section 55 and the insulating substrate 61. When viewed from the Z direction, the output section 55 faces the second electrode 54 via the insulating substrate 61 and also faces the fourth electrode 58 via the insulating substrate 61. The outer conductor 552 of the output section 55 includes an enclosing portion 552A that encloses the internal conductor 551 and a protruding portion 552B that protrudes outward from the enclosing portion 552A. In the electron detector 5, the internal conductor 551 and the enclosing portion 552A overlap the second electrode 54. The protruding portion 552B surrounds the enclosing portion 552A so as to be in direct contact with the enclosing portion 552A. The protruding portion 552B extends in the X direction to straddle the second electrode 54 and the fourth electrode 58. As a result, the protruding portion 552B overlaps with the second electrode 54 at a portion closer to the second electrode 54 than the internal conductor 551, and overlaps with the fourth electrode 58 at a portion closer to the fourth electrode 58 than the internal conductor 551.

[0047] The support section 62 includes a fixed section 621 and an interposer substrate 622. The fixed section 621 fixes the interposer substrate 622 to the insulating substrate 61. The fixed section 621 also functions as a spacer. The support section 62 adjusts the width L1 of the space SP1 between the insulating substrate 61 and the output section 55 by adjusting the thickness of the fixed section 621. The width L1 of the space SP1 is the distance in the Z direction between the insulating substrate 61 and the interposer substrate 622. The width L1 of the space SP1 is greater than 1 / 3 the thickness of the insulating substrate 61. Alternatively, the width L1 may be greater than 1 / 2 the thickness of the insulating substrate 61. The width L1 is, for example, 0.5 mm or greater and 10 mm or less.

[0048] The relay substrate 622 includes a wiring (second wiring) 622c electrically connected to the protruding portion 552B. Electrode pads are formed on a surface 622a of the relay substrate 622 on the output unit 55 side and a surface 622b opposite to the surface 622a. An electrode pad 622d formed on the surface 622b may be electrically connected to an electrode pad formed on the surface 622a via the wiring 622c. The output unit 55 is fixed to the surface 622a. In the electrode pad formed on the surface 622a, the protruding portion 552B of the output unit 55 may be fixed to the relay substrate 622 by soldering.

[0049] The relay substrate 622 has a through hole 622e that penetrates the relay substrate 622 in the Z direction. The position of the through hole 622e coincides with the position of the internal conductor 551 of the output section 55 in the X and Y directions. In the electron detector 5, the internal conductor 551 protrudes more toward the insulating substrate 61 side than the external conductor 552 in the Z direction. The internal conductor 551 is inserted through the through hole 622e. The position of the tip of the internal conductor 551 in the Z direction coincides with the surface 622b.

[0050] The electron detector 5 further includes a plurality of spring connectors 641, 642. The spring connector 641 electrically connects the output unit 55 and the second electrode 54. The spring connector 641 is disposed, for example, between the wiring 611 and the internal conductor 551. In the electron detector 5, one end of the spring connector 641 is physically connected to the electrode pad 611a, and the other end of the spring connector 641 is physically connected to the tip of the internal conductor 551. This allows an electrical signal from the AD 51 to be transmitted from the second electrode 54 to the internal conductor 551 via the wiring 611 and the spring connector 641. The spring connector 642 electrically connects the output unit 55 and the fourth electrode 58. The spring connector 642 is disposed, for example, between the wiring 612 and the wiring 622c. In the electron detector 5, one end of the spring connector 642 is physically connected to the electrode pad 612a, and the other end of the spring connector 642 is physically connected to the electrode pad 622d. As a result, the current flowing through the return path is transmitted from the protruding portion 552B to the fourth electrode 58 via the wire 622c, the spring connector 642, and the wire 612.

[0051] Each of the spring connectors 641 and 642 is a flexible conductive connector. The spring connector 641 maintains contact pressure between the electrode pad 611a and the tip of the internal conductor 551. The spring connector 642 maintains contact pressure between the electrode pad 612a and the electrode pad 622d.

[0052] As described above, the parasitic capacitance Cp is generated when the second electrode 54 and the external conductor 552 face each other. The parasitic capacitance Cp can be expressed, for example, as "Cp = ε × (S / L1)." Here, the dielectric constant ε represents the dielectric constant of the dielectric of the parasitic capacitance Cp. In this case, the dielectric is the insulating substrate 61, the relay substrate 622, and the space SP1 interposed between the second electrode 54 and the output section 55. Note that, when the electron detector 5 is placed in a vacuum, the dielectric constant of the space SP1 is the dielectric constant of the vacuum. The area S is the area where the external conductor 552 overlaps with the second electrode 54. When the area S is a fixed value, increasing the width L1 of the space SP1 reduces the parasitic capacitance Cp. However, if the width L1 is too large, while the parasitic capacitance Cp decreases, the parasitic inductance increases, which may result in increased ringing. Furthermore, the size of the electron detector 5 increases. Therefore, the width L1 may be adjusted so that both the parasitic capacitance Cp and the parasitic inductance can be reduced to a degree that does not affect the waveform of the electrical signal. Furthermore, the width L1 may be adjusted in consideration of the trade-off between the parasitic capacitance Cp and the size of the electron detector 5.

[0053] The insulating layer 63 includes a first insulating layer 631 and a second insulating layer 632. The first insulating layer 631 covers the first electrode 52 and the third electrode 57 on the other side of the resin sheet 59 in the Z direction. The first insulating layer 631 is in contact with the resin sheet 59 except for the portions of the resin sheet 59 that are in contact with the first electrode 52 and the third electrode 57. However, the first insulating layer 631 does not cover the connection portions of the anode electrode 511 and the third electrode 57 of the AD 51 with the wiring WR. The connection portions of the anode electrode 511 and the third electrode 57 with the wiring WR are exposed to the outside. The second insulating layer 632 covers the second electrode 54 and the fourth electrode 58 on one side of the resin sheet 59 in the Z direction. The second insulating layer 632 is in contact with the resin sheet 59 except for the portions of the resin sheet 59 that are in contact with the second electrode 54 and the fourth electrode 58. The second insulating layer 632 is in contact with the surface of the insulating substrate 61 on the AD 51 side. The material of the insulating layer 63 is, for example, an insulating material such as an insulating resin. [Action and effect]

[0054] In the electron detector 5, the first electrode 52 and the second electrode 54, which face each other via the resin sheet 59, function as a signal capacitor C1 that removes DC components from the electrical signal detected by the electron detection unit 53. As a result, the electrical signal from which the DC components have been removed is output from the output unit 55. Furthermore, the resin sheet 59 is used for the signal capacitor C1, and the electron detection unit 53, the resin sheet 59, and the second electrode 54 are supported by an insulating substrate 61. This ensures sufficient voltage resistance for the signal capacitor C1 and sufficient mechanical strength for the electron detector 5. Furthermore, the output unit 55 is supported by the support 62 so that a space SP1 is formed between the output unit 55 and the insulating substrate 61. This reduces the parasitic capacitance Cp generated between the output unit 55 and the second electrode 54, thereby suppressing ringing in the electrical signal due to the parasitic capacitance Cp. As described above, the electron detector 5 can improve the quality of the electrical signal.

[0055] In the electron detector 5, the width L1 of the space SP1 in the Z direction is greater than one-third the thickness of the insulating substrate 61. This allows the parasitic capacitance Cp generated between the output section 55 and the second electrode 54 to be sufficiently small.

[0056] In the electron detector 5, the support portion 62 is fixed to the insulating substrate 61. This makes it possible to stably support the output portion 55 at a desired position relative to the insulating substrate 61.

[0057] The electron detector 5 further includes a third electrode 57 disposed on the other side of the resin sheet 59 in the Z direction and spaced apart from the first electrode 52 in the X direction intersecting the Z direction, and a fourth electrode 58 disposed on one side of the resin sheet 59 in the Z direction and spaced apart from the second electrode 54 in the X direction and facing the third electrode 57 via the resin sheet 59. The output section 55 includes an internal conductor 551 electrically connected to the second electrode 54, and an external conductor 552 surrounding the internal conductor 551 while being electrically insulated from the internal conductor 551 and electrically connected to the fourth electrode 58. Thus, just as the first electrode 52 and the second electrode 54 facing each other via the resin sheet 59 function as a capacitor, the third electrode 57 and the fourth electrode 58 facing each other via the resin sheet 59 also function as a capacitor. The first electrode 52 and the second electrode 54 function as a signal capacitor C1 that removes a DC component from the electrical signal detected by the electron detector 53. As a result, the electrical signal from which the DC component has been removed is output from the internal conductor 551 of the output unit 55 via the second electrode 54. Meanwhile, the third electrode 57 and the fourth electrode 58 function as a return capacitor C2 arranged on a return path through which a return current flows from the external conductor 552. This makes it possible to suppress deterioration of the waveform of the electrical signal due to ringing and the like.

[0058] In the electron detector 5, the insulating substrate 61 includes a wiring 611 electrically connected to the second electrode 54, and the electron detector 5 further includes a spring connector 641 disposed between the wiring 611 and the internal conductor 551. This ensures reliable electrical connection between the wiring 611 and the internal conductor 551 even if a space SP1 is formed between the output section 55 and the insulating substrate 61.

[0059] In the electron detector 5, the insulating substrate 61 includes a wiring 612 electrically connected to the fourth electrode 58, the support portion 62 includes a wiring 622c electrically connected to the protruding portion 552B of the outer conductor 552, and the electron detector 5 further includes a spring connector 642 disposed between the wiring 612 and the wiring 622c. This makes it possible to reliably achieve electrical connection between the wiring 612 and the wiring 622c even if a space SP1 is formed between the output portion 55 and the insulating substrate 61.

[0060] In the electron detector 5, the electron detection unit 53 further includes an AD 51 electrically connected to the first electrode 52, and the AD 51 detects electrons emitted from the MCP 21. This allows electrons to be detected with high sensitivity due to the avalanche effect of the AD 51.

[0061] The electron detector 5 further includes an insulating layer 63 that covers the second electrode 54 and the fourth electrode 58 on one side in the Z direction with respect to the resin sheet 59, and that covers the first electrode 52 and the third electrode 57 on the other side in the Z direction with respect to the resin sheet 59. This makes it possible to prevent the electrodes from deteriorating.

[0062] The charged particle detector 1 includes an electron detector 5 and an electron emitter 2 that emits electrons in response to incident charged particles. This makes it possible to improve the quality of the electrical signal in the electron detector 5.

[0063] In the charged particle detector 1, the electron emitter 2 includes an MCP 21. This allows electrons emitted from the electron emitter 2 to be multiplied as secondary electrons, thereby increasing the electrical signal output from the electron detector 5. Furthermore, it is possible to achieve emission of secondary electrons with a high amplification factor. [Variations]

[0064] The present invention is not limited to the above-described embodiment. As shown in Fig. 5, the electron detector 5A of the first modification example differs from the electron detector 5 in that it further includes a resistor 65 electrically connected between the fourth electrode 58 and the external conductor 552. The resistor 65 connects, for example, an electrode pad formed on the surface 622a and the protruding portion 552B. The resistor 65 functions as a damping resistor to suppress ringing in the electrical signal output from the signal output terminal 56.

[0065] FIG. 6 is a graph showing an example of the behavior of an electrical signal when the resistance value of resistor 65 is changed. In FIG. 6, the electrical signal is represented as an output voltage. The horizontal axis of FIG. 6 represents time, and the vertical axis of FIG. 6 represents the normalized output voltage, which is the output voltage peak set to -100%. When the output voltage changes from -100% to 0%, ringing occurs in the output voltage. It can be seen that the ringing is greatest when the resistance value of resistor 65 is 0 Ω, and decreases as the resistance value of resistor 65 increases. It can also be seen that as the resistance value of resistor 65 increases, the amount of fluctuation from 0% after the output voltage changes to 0% is suppressed. On the other hand, it can also be seen that the time it takes for the output voltage to reach 0% increases as the resistance value of resistor 65 increases. In the electron detector 5A, resistor 65 absorbs high-frequency components of the electrical signal, thereby more reliably suppressing ringing in the electrical signal.

[0066] As shown in FIG. 7 , the electron detector 5B of the second modified example differs from the electron detector 5 in the configuration of the support portion 62. The support portion 62A of the electron detector 5B includes fixing portions 625 and 626. The fixing portions 625 and 626 fix the output portion 55 to the insulating substrate 61. The fixing portions 625 and 626 are connectors with their longitudinal direction in the Z direction. One end of each fixing portion 625 and 626 is physically connected to an electrode pad on the insulating substrate 61. Of these, the fixing portion 626 is physically connected to the electrode pad 612a. The other end of each fixing portion 625 and 626 is physically connected to the protruding portion 552B. The support portion 62A adjusts the width L1 of the space SP1 between the insulating substrate 61 and the output portion 55 by adjusting the thickness of the fixing portions 625 and 626. Furthermore, the internal conductor 551 protrudes more toward the insulating substrate 61 than the external conductor 552 in the Z direction. The length of the protruding portion of the internal conductor 551 is, for example, the same as the thickness of the fixing portions 625 and 626. The tip of the internal conductor 551 is physically connected to the electrode pad 611a.

[0067] The fixed portions 625 and 626 are conductive connectors. The fixed portion 626 electrically connects the fourth electrode 58 and the external conductor 552 via the wiring 612. This allows the current flowing through the return path to be transmitted from the protruding portion 552B to the fourth electrode 58 via the fixed portion 626 and the wiring 612.

[0068] The internal conductor 551 may be electrically connected to one of the second electrode 54 and the fourth electrode 58, and the external conductor 552 may be electrically connected to the other of the second electrode 54 and the fourth electrode 58. In the above-described embodiment and modified examples, an example in which one electrode is the second electrode 54, i.e., an example in which the internal conductor 551 is electrically connected to the second electrode 54, has been described. However, the internal conductor 551 may be electrically connected to the fourth electrode 58. In addition, in the above-described embodiment and modified examples, an example in which the other electrode is the fourth electrode 58, i.e., an example in which the external conductor 552 is electrically connected to the fourth electrode 58, has been described. However, the external conductor 552 may be electrically connected to the second electrode 54. As shown in FIG. 8 , an electron detector 5C of the third modified example differs from the electron detector 5 in that the internal conductor 551 is electrically connected to the fourth electrode 58 and the external conductor 552 is electrically connected to the second electrode 54.

[0069] The tip of the internal conductor 551 is electrically connected to the electrode pad 612a via the spring connector 642. In the electron detector 5C, an electrical signal from the AD 51 flows through the wiring WR and is transmitted to the third electrode 57. The electrical signal is then transmitted from the fourth electrode 58 to the internal conductor 551 via the wiring 612 and the spring connector 642. That is, in the electron detector 5C, the third electrode 57, the resin sheet 59, and the fourth electrode 58 form a signal capacitor C1. The protruding portion 552B is electrically connected to the electrode pad 611a via the wiring 622c, the electrode pad 622d, and the spring connector 641. As a result, the current flowing through the return path is transmitted from the protruding portion 552B to the second electrode 54 via the wiring 622c, the spring connector 641, and the wiring 611. That is, in the electron detector 5C, the first electrode 52, the resin sheet 59, and the second electrode 54 form a return capacitor C2.

[0070] The insulating substrate 61 may include a wiring (first wiring) electrically connected to the second electrode 54 or the fourth electrode 58. In the above-described embodiment, an example has been described in which the insulating substrate 61 includes the wiring (first wiring) 611 and the wiring (first wiring) 612. However, for example, the insulating substrate 61 may not include one of the wiring 611 and the wiring 612. In this case, instead of the wiring 612, a through hole penetrating the insulating substrate 61 in the Z direction may be further provided. A conductive wire may be inserted through this through hole. One end of the conductive wire may be physically connected to the spring connector 642, and the other end of the conductive wire may be physically connected to the fourth electrode 58.

[0071] The relay substrate 622 may include a wiring (second wiring) electrically connected to the internal conductor 551 or the external conductor 552. In the above-described embodiment, the relay substrate 622 includes the wiring (second wiring) 622c electrically connected to the external conductor 552. However, the relay substrate 622 may include a wiring electrically connected to the internal conductor 551. For example, the relay substrate 622 may further include a wiring instead of the through-hole 622e at a position coinciding with the internal conductor 551 in the X and Y directions. This wiring is a second wiring different from the wiring 622c, and is formed in the relay substrate 622 from the surface 622b to the surface 622a. The internal conductor 551 may be electrically connected to the spring connector 641 or the spring connector 642 via a wiring.

[0072] The electron detector 5 may have a spring connector disposed between the first wiring and the internal conductor 551 or the external conductor 552. In the above-described embodiment, the spring connector 641 is disposed between the wiring 611 (first wiring) and the internal conductor 551. However, the spring connectors 641, 642 may be disposed between the wiring 611 and the external conductor 552. For example, the spring connectors 641, 642 may be electrically connected to the external conductor 552 without a wiring. As an example, the relay substrate 622 may further be provided with a through-hole penetrating the relay substrate 622 in the Z direction, instead of the wiring 622c. A conductive wire may be inserted through this through-hole. One end of the conductive wire may be physically connected to the protruding portion 552B, and the other end of the conductive wire may be physically connected to the spring connector 641 or the spring connector 642.

[0073] The electron detection unit 53 may not include the AD 51. In this case, for example, the electron detection unit 53 is composed of a first electrode 52. The first electrode 52 may serve as both the electron detection unit 53 and the signal capacitor C1. As shown in FIG. 9 , an electron detector 5D of a fourth modification differs from the electron detector 5 in that it does not include the AD 51. Furthermore, in a charged particle detector 1A including the electron detector 5D, the electron emitter 2 may include an MCP unit 22 composed of two MCPs. In the charged particle detector 1A, a wiring WR electrically connects the third electrode 57 and the MCP unit 22. This forms a return path from the external conductor 552 to the MCP unit 22. The first electrode 52 functions as an anode electrode, which is an electron capture electrode. For example, the first electrode 52 detects electrons emitted from the MCP unit 22. In this case, unlike the AD 51, the first electrode 52 does not have an amplification function. The electron incident surface of the first electrode 52 is exposed to the outside without being covered with the first insulating layer 631. According to the charged particle detector 1A, the first electrode 52 serves as both an electrode for electron detection and an electrode for a coupling capacitor, and therefore the configuration of the electron detection unit 53 can be simplified.

[0074] The electron emitter 2 may include another electron multiplier element instead of or in addition to the MCP 21. As shown in FIG. 10 , a modified charged particle detector 1B differs from the charged particle detector 1A in that the electron emitter 2 includes a dynode unit 23 instead of the MCP 21. The dynode unit 23 includes multiple dynodes. In the dynode unit 23, each dynode emits secondary electrons and passes them on to the next dynode, gradually increasing the number of electrons. FIG. 10 shows only the final dynode. In the charged particle detector 1B, a wiring WR connects the third electrode 57 to the dynode unit 23. This forms a return path from the external conductor 552 to the dynode unit 23. According to the charged particle detector 1B, electrons emitted from the electron emitter 2 are multiplied as secondary electrons, thereby increasing the electrical signal output from the electron detector 5. Furthermore, secondary electrons can be emitted with a high amplification factor.

[0075] The above-described multiple modified examples may be combined in any manner. For example, the external conductor 552 may be electrically connected to the second electrode 54 via a resistor 65, and the internal conductor 551 may be electrically connected to the fourth electrode 58. For example, in the electron detector 5B shown in FIG. 7, the resistor 65 may be physically connected between the fixed portion 626 and the electrode pad 612a or between the fixed portion 626 and the protruding portion 552B. For example, in the electron detector 5D shown in FIG. 9 or the electron detector 5E shown in FIG. 10, the internal conductor 551 may be electrically connected to the fourth electrode 58, and the external conductor 552 may be electrically connected to the second electrode 54. For example, in the electron detector 5D or the electron detector 5E, the relay board 622 may include wiring electrically connected to the internal conductor 551, or the spring connectors 641, 642 may be physically connected to the internal conductor 551 or the external conductor 552 without wiring.

[0076] In the above-described embodiment and modified examples, the electron detector 5 is applied to the charged particle detector 1. However, the electron detector 5 may also be applied to an electron tube including a photocathode that converts photons into photoelectrons. The electron detector 5 may also be applied to, for example, a photomultiplier tube or a hybrid photodetector (HPD). A photomultiplier tube includes an electron multiplier section that multiplies photoelectrons emitted from the photocathode and emits secondary electrons. This electron multiplier section corresponds to the electron emitter section 2 in the charged particle detector 1. An HPD does not include a component corresponding to the electron emitter section 2. In an HPD, photoelectrons emitted from the photocathode directly enter the electron detector 5.

[0077] From the above-described embodiments and modifications, the charged particle detector of the present invention can also be described as follows.

[0078] The charged particle detector of the present invention is [1] "a charged particle detector comprising: an electron emitter that emits electrons in response to incidence of a charged particle; and an electron detector that outputs the electrons emitted from the electron emitter as an electrical signal, wherein the electron detector includes a first electrode and has: an electron detection unit that detects the electrons emitted from the electron emitter; a resin sheet that is arranged on one side of the first electrode in a first direction; a second electrode that is arranged on the one side of the resin sheet in the first direction and faces the first electrode via the resin sheet; an insulating substrate that is arranged on the one side of the second electrode in the first direction and supports the electron detection unit, the resin sheet, and the second electrode; an output unit that is arranged on the one side of the insulating substrate in the first direction and is electrically connected to the second electrode and outputs the electrical signal; and a support that supports the output unit so that the output unit and the second electrode face each other via the insulating substrate and so that a space is formed between the output unit and the insulating substrate."

[0079] The charged particle detector of the present invention may be [2] "the charged particle detector described in [1] above, in which the width of the space in the first direction is greater than 1 / 3 times the thickness of the insulating substrate."

[0080] The charged particle detector of the present invention may be [3] "the charged particle detector according to the above [1] or [2], wherein the support portion is fixed to the insulating substrate."

[0081] The charged particle detector of the present invention may be [4] "the charged particle detector according to any one of the above [1] to [3], wherein the electron detector further includes a third electrode that is arranged on the other side of the resin sheet in the first direction and is spaced from the first electrode in a second direction intersecting the first direction, and a fourth electrode that is arranged on the one side of the resin sheet in the first direction and is spaced from the second electrode in the second direction and faces the third electrode via the resin sheet, and the output section includes an internal conductor electrically connected to one of the second electrode and the fourth electrode, and an external conductor that surrounds the internal conductor while being electrically insulated from the internal conductor and is electrically connected to the other of the second electrode and the fourth electrode."

[0082] The charged particle detector of the present invention may be [5] "the charged particle detector described in [4] above, wherein the insulating substrate includes wiring electrically connected to the second electrode or the fourth electrode, and the electron detector further has a spring connector arranged between the wiring and the internal conductor or the external conductor."

[0083] The charged particle detector of the present invention may be [6] "the charged particle detector described in [4] above, wherein the insulating substrate includes a first wiring electrically connected to the second electrode or the fourth electrode, the support portion includes a second wiring electrically connected to the internal conductor or the external conductor, and the electron detector further has a spring connector arranged between the first wiring and the second wiring."

[0084] The charged particle detector of the present invention may be [7] "the charged particle detector according to any one of the above [4] to [6], wherein the electron detector further has a damping resistor electrically connected between the other of the second electrode and the fourth electrode and the external conductor."

[0085] The charged particle detector of the present invention may be [8] "the charged particle detector according to any one of [1] to [7] above, wherein the electron detection section further includes an avalanche diode electrically connected to the first electrode, and the avalanche diode detects the electrons emitted from the electron emission section."

[0086] The charged particle detector of the present invention may be [9] "a charged particle detector according to any one of [1] to [7] above, wherein the first electrode detects the electrons emitted from the electron emitter."

[0087] The charged particle detector of the present invention may be

[10] "the charged particle detector according to any one of the above [1] to [9], wherein the electron emitting portion includes a microchannel plate."

[0088] The charged particle detector of the present invention may be

[11] "the charged particle detector according to any one of the above [1] to [9], wherein the electron emitting portion includes a plurality of dynodes."

[0089] The charged particle detector of the present invention may be

[12] "a charged particle detector according to any one of the above [1] to

[11] , wherein the electron detector further has an insulating layer that covers the second electrode on one side in the first direction relative to the resin sheet and covers the first electrode on the other side in the first direction relative to the resin sheet." [Explanation of symbols]

[0090] 1, 1A, 1B...charged particle detector, 2...electron emitter, 23...multiple dynodes (dynode units), 5, 5A, 5B, 5C, 5D, 5E...electron detector, 51...AD (avalanche diode), 52...first electrode, 53...electron detection section, 54...second electrode, 55...output section, 57...third electrode, 58...fourth electrode, 59...resin sheet, 61...insulating substrate, 62, 62A...support section, 63...insulating layer, 65...resistor, 551...inner conductor, 552...outer conductor, 611, 612...wiring (first wiring), 622c...wiring (second wiring), 641, 642...spring connector, L1...width, SP1...space.

Claims

1. an electron detection unit including a first electrode and detecting incident electrons; a resin sheet disposed on one side of the first electrode in a first direction; a second electrode disposed on the one side of the resin sheet in the first direction and facing the first electrode with the resin sheet interposed therebetween; an insulating substrate disposed on the one side of the second electrode in the first direction and supporting the electron detection unit, the resin sheet, and the second electrode; an output section disposed on the one side of the insulating substrate in the first direction, electrically connected to the second electrode, and configured to output an electrical signal; a support portion that supports the output portion so that the output portion and the second electrode face each other via the insulating substrate and so that a space is formed between the output portion and the insulating substrate.

2. The electron detector according to claim 1 , wherein the width of the space in the first direction is greater than one-third the thickness of the insulating substrate.

3. The electron detector according to claim 1 , wherein the support portion is fixed to the insulating substrate.

4. a third electrode disposed on the other side of the resin sheet in the first direction and spaced apart from the first electrode in a second direction intersecting the first direction; a fourth electrode disposed on the one side of the resin sheet in the first direction, spaced apart from the second electrode in the second direction, and facing the third electrode with the resin sheet interposed therebetween; The output unit an internal conductor electrically connected to one of the second electrode and the fourth electrode; 3. The electron detector according to claim 1, further comprising: an outer conductor surrounding the inner conductor while being electrically insulated from the inner conductor, and electrically connected to the other of the second electrode and the fourth electrode.

5. Further comprising a spring connector, the insulating substrate includes wiring electrically connected to the second electrode or the fourth electrode, The electron detector according to claim 4 , wherein the spring connector is disposed between the wire and the inner conductor or the outer conductor.

6. Further comprising a spring connector, the insulating substrate includes a first wiring electrically connected to the second electrode or the fourth electrode, The electron detector according to claim 4 , wherein the support portion includes a second wiring electrically connected to the inner conductor or the outer conductor, and the spring connector is disposed between the first wiring and the second wiring.

7. The electron detector according to claim 4 , further comprising a resistor electrically connected between the other of the second electrode and the fourth electrode and the external conductor.

8. the electron detection unit further includes an avalanche diode electrically connected to the first electrode; 3. The electron detector according to claim 1, wherein the avalanche diode detects the electrons.

9. The electron detector according to claim 1 , wherein the first electrode detects the electrons.

10. 3. The electron detector according to claim 1, further comprising an insulating layer that covers the second electrode on the one side in the first direction with respect to the resin sheet and covers the first electrode on the other side in the first direction with respect to the resin sheet.

11. The electron detector according to claim 1 or 2; an electron emitting portion that emits electrons in response to incidence of a charged particle;

12. The charged particle detector of claim 11 , wherein the electron emitter comprises a microchannel plate.

13. The charged particle detector of claim 11 , wherein the electron emitter includes a plurality of dynodes.

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