Electronic tube and spectroscope

Abstract

To provide an electronic tube and a spectroscope capable of easily and precisely performing positioning.SOLUTION: An electronic tube 1 is mounted to a spectral section 2 for use. The electronic tube 1 includes: a casing 107 that includes a light incidence surface 102a, and has a light incidence window 102 for allowing light L2 to enter from the spectral section 2 via the light incidence surface 102a; a photoelectric conversion section 102s that is disposed in the casing 107 so as to oppose the light incidence window 102 and emits electrons according to light L2 entering from the light incidence window 102: an electron multiplication section 110 that is disposed in the casing 107 and multiplies electrons emitted from the photoelectric conversion section 102s; and a positioning member 120 that is formed separately from the light incidence window 102 and is fixed to the light incidence surface 102a, and has a light passing section 123 for passing light from the spectral section 2 toward the light incidence surface 102a. The positioning member 120 has a reference section 125 that becomes a mechanical positioning reference for the spectral section 2.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an electron tube and a spectroscope. [Background technology]

[0002] Patent Document 1 describes a photomultiplier tube that includes a main body and a support provided at an end of the main body. The main body includes a light-transmitting cylindrical member and a photomultiplier section that is housed in the cylindrical member and has a cathode and a dynode. The cathode receives light incident from outside the cylindrical member and emits photoelectrons. The emitted photoelectrons are incident on the dynode.

[0003] The photomultiplier tube is attached to a measuring device having a light-emitting portion that causes an analytical sample to emit light. Specifically, the photomultiplier tube is fixed by inserting a bolt into a fixing hole in the support and a through-hole in an opposing member of the measuring device provided at a position corresponding to the fixing hole. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6508140 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, it is sometimes difficult to achieve the mechanical precision of photomultiplier tubes as designed due to factors such as the tolerances of components, assembly precision, and manufacturing influences such as the heating process during manufacturing. This can lead to individual differences, and even if the photomultiplier tubes are attached to an external device such as the above-mentioned measuring device in the same way, differences in the optical positional relationship can occur, resulting in differences in the output signal displayed by the external device for the same input signal. In such cases, fine adjustments to the attachment state to the external device are required, and this adjustment work is not easy because it must be done while the external device is operating.

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide an electron tube and a spectrometer that can be positioned easily and with high precision. [Means for solving the problem]

[0007] The electron tube of the present invention is [1] "an electron tube attached to an external device for use, comprising: a housing having a light entrance window including a light entrance surface and through which light from the external device is incident via the light entrance surface; a photoelectric conversion unit disposed within the housing to face the light entrance window and emitting electrons in response to the light incident through the light entrance window; an electron multiplier unit disposed within the housing and multiplying the electrons emitted from the photoelectric conversion unit; and a positioning member formed separately from the light entrance window and fixed to the light entrance surface, the positioning member having a light passing portion for passing the light from the external device toward the light entrance surface, the positioning member having a reference portion that serves as a reference for mechanical positioning with respect to the external device."

[0008] This electron tube includes a housing including a light entrance window, a photoelectric conversion section and an electron multiplier section disposed inside the housing, and a positioning member fixed to the light entrance surface of the light entrance window. The positioning member has a reference section that serves as a reference for mechanical positioning with respect to an external device. The positioning member is configured separately from the light entrance window and fixed to the light entrance window. Therefore, the positioning member can be fixed to the light entrance window in a desired state after the positioning member is completed as an electron tube (after the manufacturing process as an electron tube is completed), that is, after the change in mechanical accuracy caused by the influence of the manufacturing of the electron tube is determined. Therefore, the reference section of the positioning member is not easily affected by the manufacturing of the electron tube. Therefore, when the electron tube is attached to an external device, the reference section of the positioning member can be used to perform highly accurate positioning according to the mechanical accuracy of the reference section. Therefore, this electron tube allows easy and highly accurate positioning with respect to an external device.

[0009] The electron tube according to the present invention may be [2] "the electron tube according to the above [1], in which the positioning member is fixed to the light incident surface such that the light passing portion faces the photoelectric conversion portion and the light passing through the light passing portion is incident on a desired region of the photoelectric conversion portion." In this case, highly accurate positioning can be performed so that light from an external device is guided to an appropriate region of the photoelectric conversion portion.

[0010] The electron tube according to the present invention may be [3] "the electron tube according to the above [1] or [2], in which a mark portion is formed on at least one of the positioning member, the base portion on which the photoelectric conversion portion is provided, and the electron multiplier portion." In this case, the mark portion allows for highly accurate positioning.

[0011] The electron tube according to the present invention may be [4] "an electron tube according to any one of the above [1] to [3], in which the electron multiplier section has a plurality of channels arranged in at least one direction for multiplying each of the electrons emitted from the photoelectric conversion section in response to each of the plurality of light beams incident from the light entrance window." In this way, when the electron multiplier section has a plurality of channels (multi-channel), it is more effective to enable easy and highly accurate positioning with respect to an external device. For example, when a multi-channel electron tube is attached to a spectrometer as an external device, it is necessary to position each channel of the electron tube at a position where the light of each wavelength dispersed by the spectrometer reaches. In this case, it is preferable that the electron tube can be easily positioned with high accuracy with respect to the spectrometer.

[0012] The electron tube according to the present invention may be [5] "the electron tube according to any one of the above [1] to [4], wherein the positioning member has an optical element provided in the light passing section, receiving the light from the external device and emitting the light toward the light incident surface." In this way, by adding an optical element to the positioning member that serves to perform high-precision positioning with respect to the external device, the light can be guided with high precision by the optical element arranged with high precision.

[0013] The electron tube according to the present invention may be [6] "the electron tube according to any one of the above [1] to [5], in which the reference unit has a position reference serving as a reference for the position relative to the external device and an angle reference serving as a reference for the angle relative to the external device." In this case, the position and angle relative to the external device can be easily and highly accurately determined.

[0014] The electron tube according to the present invention may be [7] "the electron tube according to any one of the above [1] to [6], in which the reference portion includes at least one of a protrusion, a hole, a notch, and an end face formed in the positioning member." In this case, the reference portion can be formed by a simple mechanical structure.

[0015] The electron tube according to the present invention may be [8] "the electron tube according to any one of the above [1] to [7], in which the positioning member has a first surface on the light incident surface side and a second surface opposite to the first surface, and an anti-reflection film is formed on at least one of the first surface and the second surface." In this case, it is possible to reduce reflection of light at the positioning member.

[0016] The electron tube according to the present invention may be [9] "the electron tube according to any one of the above [1] to [4], in which the light passing section has an opening for exposing the light incident surface to the outside." In this case, light from an external device can be made to enter the light incident surface without being reflected or refracted by a positioning member.

[0017] The electron tube according to the present invention may be

[10] "the electron tube according to the above [4], wherein the positioning member is provided in the light passing section and includes an optical element that receives the light from the external device and emits the light toward the light incident surface, the optical element including a plurality of optical structures aligned with each of the plurality of channels." In this case, it is possible to efficiently input light to each of the plurality of channels in the electron multiplier section.

[0018] The electron tube according to the present invention may be

[11] "the electron tube according to the above

[10] , comprising a light-collecting element provided on the surface opposite to the light incident surface of the optical element and having a light-collecting structure in a plane intersecting the arrangement direction of the channels." In this case, the field of view in the plane intersecting the arrangement direction of the multiple channels can be widened.

[0019] The spectrometer according to the present invention is

[12] "a spectrometer comprising a spectroscopic unit as the external device for dispersing detection light into light of a plurality of wavelengths and emitting the light, and the electron tube according to any one of [1] to

[11] above." In this case, the electron tube can be positioned easily and with high accuracy with respect to the spectroscopic unit.

[0020] The spectrometer according to the present invention may be the spectrometer according to

[13] above, "wherein the spectroscopic unit comprises: a dispersive element disposed on the optical path of the detection light for dispersing the detection light into light of the plurality of wavelengths; and a wavelength selection element disposed on the optical path of the detection light upstream of the dispersive element for reflecting or absorbing light of a specific wavelength band of the detection light." In this case, it becomes possible to reflect or absorb light that becomes noise in the detection light by the wavelength selection element. Effect of the Invention

[0021] According to the present invention, it is possible to provide an electron tube and a spectrometer that can be positioned easily and with high precision. [Brief description of the drawings]

[0022]

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[0023] Hereinafter, an electron tube and a spectrometer according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same or corresponding elements may be denoted by the same reference numerals, and redundant descriptions may be omitted. In each figure, a rectangular coordinate system may be shown that includes an axis defining a first direction D1, an axis defining a second direction D2 that intersects the first direction D1, and an axis defining a third direction that intersects the first direction D1 and the second direction D2.

[0024] FIG. 1 is a schematic cross-sectional view of a spectrometer according to the present embodiment. The spectrometer 1 shown in FIG. 1 is used, for example, for spectroscopic measurement of weak light such as fluorescence and Raman scattered light, and is particularly used in a flow cytometer.

[0025] The spectrometer 1 shown in FIG. 1 includes a spectroscopic unit (external device) 2 and a detection unit 3. The spectroscopic unit 2 splits the detection light L1 emitted from the optical fiber 4 into lights L2 of a plurality of wavelengths and emits them toward the detection unit 3.

[0026] The spectroscopic unit 2 includes a housing 10 and an optical system 20. The housing 10 has a housing portion 11 and a mounting portion 12. The housing portion 11 houses the optical system 20. The housing portion 11 includes one end portion to which the optical fiber 4 is attached and into which the detection light L1 guided by the optical fiber 4 is incident, and the other end portions that emit the lights L2 after spectroscopy. The mounting portion 12 is disposed at the other end portion. The mounting portion 12 has a surface 12a on the side opposite to the housing portion 11. A plurality of positioning pins 12c for insertion into a through hole 212 described later are formed on the surface 12a to position the detection unit 3 with high precision with respect to the spectroscopic unit 2.

[0027] The optical system 20 has a collimating lens 21, a filter (wavelength selection element) 22, a diffraction grating (dispersion element) 23, and an imaging lens 24. The detection light L1 emitted from the optical fiber 4 passes through the collimating lens 21 and the filter 22 in this order, and is incident on the diffraction grating 23. The collimating lens 21 collimates the detection light L1 emitted from the optical fiber 4 and emits it toward the filter 22. Note that in this embodiment, the collimating lens 21, the filter 22, the diffraction grating 23, and the imaging lens 24 of the optical system 20 are each composed of a single optical element, but each of these may be composed of a plurality of optical elements.

[0028] The filter 22 is disposed in front of the diffraction grating 23 on the optical path of the detection light L1. Specifically, the filter 22 is disposed between the collimator lens 21 and the diffraction grating 23 on the optical path of the detection light L1. The filter 22 selects the wavelength of light traveling toward the diffraction grating 23 by reflecting or absorbing light in a specific wavelength band included in the detection light L1 (for example, excitation light of the object to be measured in the spectroscopic section 2). This allows the filter 22 to reflect or absorb light that becomes noise in the detection light L1.

[0029] The diffraction grating 23 is, for example, a transmissive diffraction grating, which separates the detection light L1 incident from the filter 22 into light L2 of a plurality of wavelength bands, and emits each of the light L2 toward the imaging lens 24. The light L2 emitted from the diffraction grating 23 passes through the imaging lens 24 and is incident on a light incident surface 102a (described later) of the electron tube 100. The diffraction grating 23 may be a reflective diffraction grating, or a prism may be used instead of the diffraction grating. The imaging lens 24 forms an image of the light L2 emitted from the diffraction grating 23 on the light incident surface 102a (described later).

[0030] The detection unit 3 has an electron tube 100 and a case 200. The electron tube 100 is, for example, a HPD (hybrid photodetector). The electron tube 100 detects light emitted from the spectroscopic unit 2. The electron tube 100 is attached to the spectroscopic unit 2 so as to face the imaging lens 24. Specifically, the electron tube 100 is fixed to the mounting portion 12 of the spectroscopic unit 2 via the case 200 in a state where it is accommodated in the case 200. In the following, the configuration of the case 200 will be described first, and then the configuration of the electron tube 100 will be described. Also, the direction in which the imaging lens 24 faces a light incident surface 102a described later (i.e., the direction intersecting the light incident surface 102a) is defined as a first direction D1.

[0031] The configuration of the case 200 will be described with reference to Figures 1 to 3. Figure 2 is a cross-sectional view of the detection unit 3. Figure 3 is a view of the detection unit 3 as viewed from the imaging lens 24 side.

[0032] The case 200 has a top plate 201, a side wall portion 202, and a cover member 203. The case 200 houses the electron tube 100.

[0033] The top plate 201 is formed in a plate shape. The top plate 201 has a first surface 201a and a second surface 201b opposite to the first surface 201a. The first surface 201a faces the surface 12a of the attachment portion 12 in the first direction D1. The second surface 201b faces the light incident surface 102a of the electron tube 100 in the first direction D1. As an example, the top plate 201 is formed in a rectangular shape with the four corners cut out in a semicircular shape when viewed from the first direction D1.

[0034] The top plate 201 has an opening 211 , a plurality of through holes 212 , a protruding portion 213 , a pair of protruding portions 214 , and a recessed portion 215 .

[0035] When viewed from the first direction D1, the opening 211 exposes a positioning member 120 (described later) of the electron tube 100. As a result, the light L2 emitted from the spectroscopic section 2 is incident on the positioning member 120 through the opening 211.

[0036] The plurality of through holes 212 are through holes formed in the top plate 201 along the first direction D1. The plurality of through holes 212 are mechanical references that define the positional relationship between the spectroscopic unit 2 and the case 200 (detection unit 3). The plurality of through holes 212 are formed at positions corresponding to the plurality of positioning pins 12c of the attachment portion 12 when viewed from the first direction D1. The detection unit 3 is fixed to the attachment portion 12 via the top plate 201 by inserting the positioning pins 12c into the through holes 212. The insertion structure between the positioning pins 12c and the through holes 212 can be formed such that the outer wall surface of the positioning pins 12c and the inner wall surface of the through holes 212 are separated by a gap of about several micrometers, so that very high-precision positioning can be achieved. Then, the spectroscopic unit 2 and the case 200 (detection unit 3) are securely coupled by a screwing structure using screws and screw hole portions (not shown) while being positioned by the insertion structure between the positioning pins 12c and the through holes 212. Thereby, the positional relationship between the spectroscopic unit 2 and the case 200 (detection unit 3) is mechanically defined.

[0037] The protruding portion 213 is formed on the second surface 201b of the top plate 201. The protruding portion 213 is formed inside the side tube 103 (to be described later) of the electron tube 100 when viewed from the first direction D1. The protruding portion 213 is in contact with the light incident surface 102a of the electron tube 100. The protruding portion 213 is formed, for example, in an annular shape when viewed from the first direction D1.

[0038] The pair of protruding portions 214 are formed on the second surface 201b of the top plate 201. The pair of protruding portions 214 are mechanical references for defining the positional relationship between the electron tube 100 and the case 200. The pair of protruding portions 214 are provided inside the protruding portion 213 when viewed from the first direction D1, and are formed to face each other in the second direction D2 with the opening 211 interposed therebetween. The pair of protruding portions 214 extend, for example, in a columnar shape from the second surface 201b toward the light incident surface 102a.

[0039] The recess 215 is formed on the first surface 201a of the top plate 201. The recess 215 is formed in a columnar shape. The recess 215 has an annular bottom surface 215a. The above-mentioned opening 211 is formed in this bottom surface 215a. Inside the recess 215, a wavelength selection filter (not shown) disposed on the bottom surface 215a in a state of covering the opening 211 is accommodated. The filter is for removing, for example, second-order diffracted light generated by the diffraction grating 23, and a structure in which a plurality of types of wavelength selection filters are arranged is preferable so that unnecessary second-order diffracted light can be removed for each channel ch described later.

[0040] The side wall portion 202 is formed in a cylindrical shape having a central axis along the first direction D1. The side wall portion 202 extends from the second surface 201b of the top plate 201 toward the side opposite to the first surface 201a. A lid member 203 is attached to the end portion 202a of the side wall portion 202 opposite to the top plate 201.

[0041] The lid member 203 is formed, for example, in an annular plate shape having an opening. The lid member 203 is fixed to the end portion 202a of the side wall portion 202 by a lid fixing member 205 such as a screw. The above top plate 201, side wall portion 202, and lid member 203 are formed of, for example, an insulating light-shielding material, for example, a black resin, thereby constituting an insulating and light-shielding case 200. Further, the case 200 holds the electron tube 100 by sandwiching the electron tube 100 in the first direction D1 between the lid member 203 and the top plate 201.

[0042] With reference to FIGS. 4 to 7, the configuration of the electron tube 100 will be described. FIG. 4 is a perspective view of the electron tube 100. FIG. 5 is a plan view of the electron tube 100. FIG. 6 is a schematic cross-sectional view of the electron tube 100. FIG. 7 is a schematic plan view of the electron multiplier section.

[0043] The electron tube 100 includes a light incident window 102, a photoelectric conversion section 102s, a side tube 103, a stem 104, a base member 105, pins 106, an electron multiplication section 110, and a positioning member 120. The light incident window 102, the side tube 103, and the stem 104 constitute a housing 107. The light incident window 102 includes a light incident surface 102a and a back surface 102b on the side opposite to the light incident surface 102a. The light incident window 102 is made of a light transmissive material such as glass, for example, and transmits the light incident from the light incident surface 102a toward the back surface 102b. The light incident window 102 is formed in a circular flat plate shape (i.e., a disk shape), for example.

[0044] The photoelectric conversion section 102s is provided on the back surface 102b of the light incident window 102 as a base material section. That is, the photoelectric conversion section 102s is disposed in the housing 107 so as to face the light incident window 102. The photoelectric conversion section 102s includes a photoelectric conversion layer made of a thin film of a compound semiconductor such as GaAs, for example, and emits photoelectrons in response to the light L2 incident from the light incident window 102. Note that the photoelectric conversion section 102s may be a so-called alkali photocathode. The photoelectric conversion section 102s is a transmissive photocathode, for example.

[0045] The side tube 103 is formed in a tubular shape (here, a circular tubular shape) with both ends open by an insulating material such as ceramic, for example. One end of the side tube 103 is sealed by the light incident window 102. The stem 104 is formed in a plate shape (here, a disk shape) by an insulating material such as ceramic, for example, and seals the other end of the side tube 103. Thereby, a vacuum region can be formed in the side tube 103. In the present embodiment, a voltage can be applied so that the stem 104 side becomes the GND potential with respect to the photoelectric conversion section 102s (the photoelectric conversion section 102s has a negative potential and the stem 104 side becomes the ground potential) (see FIG. 2).

[0046] The base member 105 is provided on the stem 104 so as to be located within the side tube 103. The base member 105 has a top surface 105a which is a surface facing the photoelectric conversion unit 102s, and is formed in a rectangular parallelepiped block shape that protrudes convexly from the stem 104 toward the photoelectric conversion unit 102s by an insulating material such as ceramic. A plurality (for example, the same number as the channel ch described later) of pins 106 are provided through the base member 105 so that each can output an electrical signal detected by the electron multiplication unit 110 to the outside. For example, one end of the pin 106 reaches the surface (top surface 105a) of the base member 105 opposite to the stem 104, and the other end of the pin 106 protrudes from the surface of the base member 105 on the stem 104 side to the outside of the side tube 103. Note that the base member 105 may be integrally formed with the stem 104, and the pin 106 and the electron multiplication unit 110 may be electrically connected via other conductive members such as wiring.

[0047] The electron multiplication unit 110 multiplies the electrons emitted from the photoelectric conversion unit 102s. The electron multiplication unit 110 is, for example, a semiconductor element. The electron multiplication unit 110 is disposed within the housing 107. The electron multiplication unit 110 is disposed on the top surface 105a of the base member 105 so as to face the photoelectric conversion unit 102s along the first direction D1. More specifically, the electron multiplication unit 110 includes a back surface 110r and a front surface 110s, and is provided on the top surface 105a of the base member 105 such that the back surface 110r (that is, the electron incident surface 111s described later) faces the photoelectric conversion unit 102s (the front surface 110s faces the top surface 105a side of the base member 105).

[0048] The electron multiplication unit 110 is electrically connected to the pin 106 by bump connection as an example. The electron multiplication unit 110 is, for example, an AD (Avalanche diode). The electron multiplication unit 110 receives the incidence of photoelectrons from the photoelectric conversion unit 102s, generates multiplication by electron bombardment, and further generates multiplication by avalanche multiplication. Also, in the present embodiment, the electron multiplication unit 110 uses a back-illuminated semiconductor element.

[0049] The electron multiplication section 110 has a first part 111 and a second part 112. The first part 111 has an electron incident surface 111s which is the surface facing the photoelectric conversion section 102s. The electron incident surface 111s includes a plurality of channels ch arranged while being spaced apart from each other along a second direction D2 intersecting a first direction D1. In other words, the electron incident surface 111s is a photoelectron detection surface in the electron multiplication section 110, and includes a sensitivity region which is a plurality of channels ch and an insensitive region R formed between the individual channels ch. The electron multiplication section 110 multiplies (detects) photoelectrons in each of the plurality of channels ch. That is, the plurality of channels ch multiply each of the electrons emitted from the photoelectric conversion section 102s according to each of the plurality of lights L2 incident from the photoelectric conversion section 102s. In the present embodiment, the electron multiplication section 110 is a so-called one-dimensional sensor (line sensor) in which a plurality of channels ch are arranged in a line, but it may also be a so-called two-dimensional sensor (area sensor) in which a plurality of channels ch are arranged in a plurality of lines.

[0050] The second part 112 is provided at least on both end sides of the electron incident surface 111s in the second direction D2. In the present embodiment, the second part 112 is formed in a rectangular frame shape so as to surround the electron incident surface 111s when viewed from the first direction D1. The second part 112 is formed thicker than the first part 111 by protruding toward the photoelectric conversion section 102s side from the electron incident surface 111s. A potential is applied between the photoelectric conversion section 102s and the electron incident surface 111s such that the photoelectrons emitted from the photoelectric conversion section 102s head toward the electron incident surface 111s with a desired acceleration. In the present embodiment, a voltage is applied such that the electron incident surface 111s side is at the GND potential (such that the photoelectric conversion section 102s is at a negative potential and the electron incident surface 111s side is at the ground potential).

[0051] The second part 112 has a surface 112a which is the surface facing the photoelectric conversion part 102s. The second part 112 has a plurality of first reference lines (marking parts) 113 formed on the surface 112a. The plurality of first reference lines 113 are so-called alignment lines, and are preferably physical structures that can be visually confirmed, such as a metal film, a groove, or a protrusion. The plurality of first reference lines 113 serve as a reference for aligning the positioning member 120 described later.

[0052] The plurality of first reference lines 113 have a pair of first lines 113a and a pair of second lines 113b, and are respectively arranged at the center in the short side direction (third direction D3) of the first part 111 and the center in the long side direction (second direction D2) of the first part 111. The pair of first lines 113a are straight lines along the second direction D2 formed on the surface 112a. The pair of first lines 113a are formed so as to face each other via the first part 111 on both sides of the second part 112 in the second direction D2. That is, the pair of first lines 113a are straight lines extending outward in the second direction D2 from both end portions of the first part 111 in the second direction D2.

[0053] The pair of second lines 113b are straight lines along the third direction D3 formed on the surface 112a. The pair of second lines 113b are formed so as to face each other via the first part 111 on both sides of the second part 112 in the third direction D3. That is, the pair of second lines 113b are straight lines extending outward in the third direction D3 from both end portions of the first part 111 in the third direction D3.

[0054] Figs. 8(a) to (c) are views of the electron multiplication part 110 and the positioning member 120 as seen from above the light incident surface 102a. Fig. 8(a) is a view showing only the positioning member 120. Fig. 8(b) is a view showing only the electron multiplication part 110. Fig. 8(c) is a view showing a state in which the positioning member 120 is arranged on the electron multiplication part 110.

[0055] Referring to FIGS. 6 and 8, the positioning member 120 will be described. The positioning member 120 is formed separately from the light incident window 102 as a rectangular member having the second direction D2 as its longitudinal direction by a light-transmissive material, such as a light-transmissive resin or glass, and is fixed (e.g., adhered) to the light incident surface 102a of the light incident window 102. The positioning member 120 is fixed to the light incident surface 102a such that the light passing portion 123 faces the photoelectric conversion portion 102s and the light L2 passing through the light passing portion 123 is incident on a desired region of the photoelectric conversion portion 102s. The positioning member 120 is formed in a plate shape. The positioning member 120 has a first surface 120a on the light incident surface 102a side and a second surface 120b on the side opposite to the first surface 120a.

[0056] An antireflection film 120s is formed on at least one of the first surface 120a and the second surface 120b of the positioning member 120. In the case of the present embodiment, the antireflection film 120s is formed on both the first surface 120a and the second surface 120b. Therefore, the positioning member 120 is arranged such that the first surface 120a faces the light incident surface 102a and is fixed to the light incident surface 102a via the antireflection film 120s.

[0057] The positioning member 120 has a plate-like portion 121 and a cylindrical lens array (optical element) 122. The plate-like portion 121 is formed in a rectangular shape having the second direction D2 as its longitudinal direction. The plate-like portion 121 includes the second surface 120b. The corner portion 121c of the plate-like portion 121 is chamfered, for example, in a C-plane shape. The plate-like portion 121 has a light passing portion 123, a frame portion 124, a reference portion 125, and a plurality of second reference lines (marking portions) 126.

[0058] The light passing portion 123 is formed at the center of the plate-like portion 121 when viewed in the first direction D1. The light passing portion 123 is formed in a rectangular shape having the second direction D2 as its longitudinal direction. The light passing portion 123 allows the light L2 from the spectroscopic unit 2 to pass through toward the light incident surface 102a of the light incident window 102. The positioning member 120 and the light passing portion 123 are arranged so as to overlap the electron multiplication unit 110 when viewed in the first direction D1.

[0059] When viewed from the first direction D1, the frame portion 124 is formed in a rectangular frame shape so as to surround the light passing portion 123. Note that the frame portion 124 does not necessarily need to have light transmissivity and may be formed of a light-shielding material separate from the light passing portion 123.

[0060] The reference portion 125 is formed on the frame portion 124. The reference portion 125 serves as a mechanical positioning reference for the spectroscopic portion 2. The reference portion 125 has a first through hole 125a and a second through hole 125b. The first through hole 125a is formed at one end of the frame portion 124 in the second direction D2. The first through hole 125a is a through hole along the first direction D1. The first through hole 125a is formed, for example, in a perfect circular shape when viewed from the first direction D1. The first through hole 125a is a mechanical structure and is a position reference for the position with respect to the spectroscopic portion 2. That is, the first through hole 125a provides a mechanical position reference by inserting a protrusion that fits on the inner wall surface of the first through hole 125a, more preferably a protrusion having a circular cross-section.

[0061] The second through hole 125b is formed at the other end of the frame portion 124 in the second direction D2. The second through hole 125b is a through hole along the first direction D1. The second through hole 125b is an elongated hole having an oval shape with the second direction D2 as the longitudinal direction when viewed from the first direction D1. The second through hole 125b is a mechanical structure and is an angle reference for the angle with respect to the spectroscopic portion 2. That is, the second through hole 125b provides an angle reference that allows mechanical angle adjustment while restricting the rotation of the positioning member 120 together with the first through hole 125a by inserting a protrusion having mobility inside the second through hole 125b at a position different from the first through hole 125a.

[0062] As shown in FIG. 8(a), a plurality of second reference lines 126 are formed on the second surface 120b. The plurality of second reference lines 126 include a pair of first lines 126a and a second line 126b, and are respectively arranged at the center in the short-side direction (third direction D3) of the light passage portion 123 and at the center in the long-side direction (second direction D2) of the light passage portion 123. The plurality of second reference lines 126 are so-called alignment lines used when positioning the positioning member 120 with respect to the electron multiplication portion 110, and are preferably physical structures that can be visually confirmed, such as a metal film, a groove, or a protrusion. Further, the plurality of second reference lines 126 may be formed on the light incident window 102 that serves as the base material portion on which the photoelectric conversion portion 102s is formed. That is, a mark portion (a plurality of first reference lines 113 or a plurality of second reference lines 126) is formed on at least one of the positioning member 120, the light incident window 102 (base material portion) provided with the photoelectric conversion portion 102s, and the electron multiplication portion 110.

[0063] The pair of first lines 126a are straight lines along the second direction D2 formed on the second surface 120b. The pair of first lines 126a are formed to face each other via the light passage portion 123 on both sides of the frame portion 124 in the second direction D2. That is, the pair of first lines 126a are straight lines extending outward in the second direction D2 from both end portions of the light passage portion 123 in the second direction D2.

[0064] The second line 126b is a straight line along the third direction D3 formed on the second surface 120b. The second line 126b is formed on one side of the light passage portion 123 in the third direction D3. That is, the second line 126b is a straight line extending outward in the third direction D3 from one end portion of the light passage portion 123 in the third direction D3.

[0065] Here, with reference to FIG. 8, the positioning procedure of the electron multiplier unit 110 and the positioning member 120 will be described. First, as shown in FIG. 8(a), the positioning member 120 is prepared. Next, as shown in FIG. 8(b), it is confirmed that the electron multiplier unit 110 is visible. Next, as shown in FIG. 8(c), the positioning member 120 is fixed to the light incident surface 102a such that the first line 113a of the electron multiplier unit 110 coincides with the first line 126a of the positioning member 120 and the second line 113b of the electron multiplier unit 110 coincides with the second line 126b of the positioning member 120. Thereby, the positioning member 120 is positioned with respect to the electron multiplier unit 110.

[0066] Note that the positioning member 120 is originally positioned and fixed to the light incident window 102 so that light (light L2 of a plurality of wavelengths in this embodiment) from an external device is appropriately incident on a desired region of the photoelectric conversion unit 102s. However, since the photoelectric conversion unit 102s is made of a thin film, it is difficult to provide a reference line (marking portion) on the photoelectric conversion unit 102s itself. Therefore, in the case of the transmission type photoelectric conversion unit 102s (transmission type photocathode) such as the electron tube 100 of this embodiment, by providing a reference line on the light incident window 102 which is the base material portion on which the photoelectric conversion unit 102s is formed, it is also possible to position the positioning member 120. However, when a reference line is provided on the light incident window 102 which serves as the light incident surface and the light exit surface, there is a possibility that the reference line may become an obstacle during light detection. Therefore, in this embodiment, a reference line is provided on the electron multiplier section 110. In the case of a transmission type photocathode, since the photoelectrons emitted from the photoelectric conversion unit 102s basically go toward the electron multiplier section 110 in a projective positional relationship, by appropriately positioning with respect to the electron multiplier section 110, the positioning with respect to the photoelectric conversion unit 102s also becomes appropriate. Furthermore, in this embodiment, since the reference line is provided in the second portion 112 of the electron multiplier section 110, that is, in a region other than the electron incident surface 111s, the reference line does not become an obstacle to electron multiplication. In the case of an electron tube 100B provided with a reflective photocathode as shown in FIG. 17, instead of the transmission type photoelectric conversion unit 102s such as the electron tube 100 of this embodiment, even if a reference line is provided on the base material portion on which the photocathode is formed, the reference line does not become an obstacle during light detection, and the positioning member 120 can be appropriately positioned.

[0067] As shown in FIGS. 6 to 9, the cylindrical lens array 122 is provided on the surface of the light passage portion 123 and includes the second surface 120b. The cylindrical lens array 122 receives the incidence of the light L2 from the spectroscopic unit 2 and emits the light L2 toward the light incident surface 102a.

[0068] The cylindrical lens array 122 includes a plurality of cylindrical lenses (optical structures) 122a. The plurality of cylindrical lenses 122a are arranged along the second direction D2. Each of the plurality of cylindrical lenses 122a has a curvature in the plane along the second direction D2. Each of the cylindrical lenses 122a is arranged to be convex toward the side opposite to the light incident surface 102a of the light incident window 102. The plurality of cylindrical lenses 122a are aligned with respective ones of the plurality of channels ch. Specifically, as shown in FIG. 9, the cylindrical lenses 122a are aligned such that the light L2 emitted from the plurality of cylindrical lenses 122a is incident on respective ones of the plurality of channels ch of the corresponding electron multiplying section 110. That is, the plurality of cylindrical lenses 122a are aligned so that the light L2 does not enter the insensitive region R of the electron multiplying section. Thereby, light can be efficiently incident on each of the plurality of channels ch.

[0069] Note that the cylindrical lenses 122a may be arranged at equal pitches or at unequal pitches along the second direction D2. When arranging the cylindrical lenses 122a at unequal pitches, the arrangement of the cylindrical lenses 122a can be set as follows. That is, when the chief ray of the light L2 enters the cylindrical lens 122a at the incident angle θ, the center of the cylindrical lens 122a may be shifted by f·tanθ from the center of the channel ch of the electron multiplication section 110 (f is the focal length). When the light L2 is imaged by a non-telecentric optical system, the chief ray angle on the image plane varies depending on the field of view. As a result, it is advantageous for the cylindrical lenses 122a to have unequal pitches. Also, in this case, the optical system for imaging the light L2 is not limited to an image-side telecentric arrangement. Therefore, it is possible to avoid restrictions on the arrangement of the optical system, such as fixing the distance between the diffraction grating 23 and the imaging lens 24 for an image-side telecentric arrangement and an increase in the size of the lens. Note that in the present embodiment, the cylindrical lens array 122 (cylindrical lens 122a) is integrally formed with the plate-like portion 121, but it may be separate. In this case, the cylindrical lens array 122 (cylindrical lens 122a) may be fixed on the light passage portion 123 made of a translucent member on the flat plate, or may be fixed so as to fit into the light passage portion 123 formed as an opening.

[0070] The electron tube 100 configured as described above is mechanically positioned with respect to the case 200 by being sandwiched between the top plate 201 of the case 200 and the lid member 203 while each of a pair of protrusions 214 of the case 200 is inserted into each of the first through-hole 125a and the second through-hole 125b of the positioning member 120. Then, the case 200 is mechanically positioned and fixed with respect to the spectroscopic unit 2 by inserting each of the positioning pins 12c of the mounting portion 12 of the spectroscopic unit 2 into each of the plurality of through-holes 212 of the case 200. As a result, the electron tube 100 is mechanically positioned with respect to the spectroscopic unit 2. That is, the electron tube 100 is mechanically positioned with respect to the spectroscopic unit 2 using the positioning member 120 via the case 200. At this time, inside the electron tube 100, since the positioning member 120 is positioned with respect to the electron multiplier unit 110 which is the internal structure of the housing 107, the positioning between the spectroscopic unit 2 and the electron multiplier unit 110 is also realized.

[0071] As described above, the electron tube 100 includes a housing 107 including an optical input window 102, a photoelectric conversion unit 102s and an electron multiplier unit 110 disposed inside the housing 107, and a positioning member 120 fixed to the light incident surface 102a of the optical input window 102. The positioning member 120 has a reference portion 125 that serves as a reference for mechanical positioning with respect to the spectroscopic unit 2. This positioning member 120 is configured separately from the optical input window 102 and is fixed to the optical input window 102. Therefore, after the positioning member 120 is completed as the electron tube 100 (after the manufacturing process as the electron tube 100 is completed), that is, after the change in mechanical accuracy due to the influence related to the manufacturing of the electron tube 100 is determined, the positioning member 120 can be fixed to the optical input window 102 in a desired state. Therefore, the reference portion 125 of the positioning member 120 is hardly affected by strain in, for example, a heating process for sealing the housing 107 (optical input window 102) related to the manufacturing of the electron tube 100. Therefore, when attaching the electron tube 100 to the spectroscopic unit 2, by using the reference portion 125 of the positioning member 120, high-precision positioning according to the mechanical accuracy of the reference portion 125 is possible. Therefore, according to this electron tube 100, it is possible to easily and highly accurately position with respect to the spectroscopic unit 2.

[0072] The positioning member 120 is fixed to the light incident surface 102a such that the light passing portion 123 faces the photoelectric conversion portion 102s and the light L2 passing through the light passing portion 123 is incident on a desired region of the photoelectric conversion portion 102s. Thereby, highly accurate positioning can be performed so as to guide the light L2 from the spectroscopic unit 2 to an appropriate region of the photoelectric conversion unit 102s.

[0073] A mark portion is formed on at least one of the positioning member 120, the light incident window 102 provided with the photoelectric conversion portion 102s, and the electron multiplier portion 110. Thereby, highly accurate positioning can be performed by the mark portion.

[0074] The electron multiplier portion 110 has a plurality of channels ch. When the electron multiplier portion 110 is a multi-channel having a plurality of channels ch in this way, since it is necessary to make the light split by the spectroscopic unit 2 enter the channels ch corresponding to the respective wavelengths, more highly accurate positioning is required. Even in such a case, easy and highly accurate positioning with respect to the spectroscopic unit 2 can be enabled.

[0075] The reference portion 125 has a first through hole 125a serving as a reference for the position with respect to the spectroscopic unit 2 and a second through hole 125b serving as a reference for the angle with respect to the spectroscopic unit 2. Thereby, the position and angle with respect to the spectroscopic unit 2 can be easily and highly accurately determined.

[0076] An antireflection film 120s is formed on at least one of the first surface 120a and the second surface 120b of the positioning member 120. Thereby, the reflection of light in the positioning member 120 can be reduced.

[0077] The cylindrical lens array 122 is provided on the surface of the light passing portion 123. The cylindrical lens array 122 receives the incidence of the light L2 from the spectroscopic unit 2 and emits the light L2 toward the light incident surface 102a. The plurality of cylindrical lenses 122a of the cylindrical lens array 122 are aligned with each of the plurality of channels ch. Thereby, as described above, it becomes possible to efficiently make the light L2 incident on each of the plurality of channels ch of the electron multiplication unit.

[0078] The spectroscope 1 includes a spectroscopic unit 2 for splitting the detection light L1 into lights L2 of a plurality of wavelengths and emitting the split lights, and an electron tube 100. Thereby, the electron tube 100 can be easily and highly accurately positioned with respect to the spectroscopic unit 2.

[0079] The spectroscope 1 includes a filter 22. The filter 22 is arranged in front of the diffraction grating 23 on the optical path of the detection light L1 and reflects or absorbs light in a specific wavelength band of the detection light L1. Thereby, it becomes possible to reflect or absorb the light that becomes noise with respect to the detection light L1 by the filter 22.

[0080] The above embodiments illustrate one aspect of the present invention. Therefore, the present invention is not limited to the spectroscope 1 described above and can be arbitrarily modified. Subsequently, modification examples will be described.

[0081] The electron multiplication unit 110 of the electron tube 100 may not have a plurality of first reference lines 113. In this case, for example, the pattern of the semiconductor element that is the electron multiplication unit 110 can be used instead of the first reference line 113 for positioning between the positioning member 120 and the electron multiplication unit 110. As an example of the pattern of the semiconductor element, there is a pattern of a plurality of channels ch of the electron incident surface 111s (for example, a line formed on the outer edge of each channel).

[0082] Further, the positioning member 120 may not have a plurality of second reference lines 126. In this case, for the positioning between the positioning member 120 and the electron multiplication unit 110, any structure (such as the cylindrical lens array 122) or reference portion 125 of the positioning member 120 can be used instead of the plurality of second reference lines 126.

[0083] FIG. 10 is a diagram for explaining a positioning method without using the first reference line 113 and the second reference line 126. First, as shown in FIG. 10(a), the electron multiplication unit 110 is observed by a camera from above the light incident surface 102a. Next, based on an arbitrary position of the pattern of a plurality of channels ch formed on the electron incident surface 111s of the electron multiplication unit 110, the reference is aligned with two orthogonal electron lines A displayed on the camera. Next, as shown in FIG. 10(b), the positioning member 120 is disposed on the light incident surface 102a. Next, two orthogonal electron lines B different from the electron lines A are displayed on the camera at positions where the reference portion 125 (the first through hole 125a and the second through hole 125b) of the positioning member 120 is designed to be disposed. Then, the positioning member 120 is adjusted and fixed on the light incident surface 102a such that the distance between each of the electron lines A and each of the electron lines B is an ideal distance in design and the reference portion 125 is aligned with the electron lines B (for example, the intersection of the electron lines B is located at the center of the first through hole 125a).

[0084] In the above embodiment, the reference portion 125 has the first through hole 125a and the second through hole 125b, but the reference portion 125 is not limited to holes and may include at least one of a protrusion, a notch, and an end face. For example, as shown in FIG. 11(a), the reference portion 125 may be a notch 125c formed on the outer edge of the frame portion 124. In this case, for example, by inserting the protrusion 214 formed on the top plate 201 of the case 200 into the notch 125c (by abutting the protrusion 214 against the inner surface of the notch 125c), the electron tube 100 can be mechanically positioned with respect to the spectroscopic unit 2.

[0085] Further, as shown in FIG. 11(b), the reference portion 125 may be an end face 125d facing the outside of the frame portion 124. In this case, for example, by abutting the protrusion 220 (for example, a pin) formed on the top plate 201 against the end face 125d, the electron tube 100 can be mechanically positioned with respect to the spectroscopic unit 2. Further, as shown in FIGS. 12(a) and (b), the reference portion 125 may include a protrusion 125e. In this case, for example, by forming a hole in the top plate 201 and inserting the protrusion 125e into the hole, the electron tube 100 can be mechanically positioned with respect to the spectroscopic unit 2. In any of these cases, the electron tube 100 can be positioned with high precision. Note that in FIGS. 11 and 12, the cylindrical lens array 122 and the light passage portion 123 are omitted.

[0086] Further, as shown in FIG. 13, an opening 123b may be formed in the light passage portion 123 to expose the light incident surface 102a of the light incident window 102 to the outside. That is, in the region where the light L2 passes through the light passage portion 123, an opening 123b as a gap may be formed in the light passage portion 123 by removing the light-transmitting material constituting the light passage portion 123. In this case, the light L2 from the spectroscopic unit 2 can be made to enter the light incident surface 102a without going through reflection, refraction, etc. in the positioning member 120.

[0087] As shown in FIG. 14, the positioning member 120 may further include a lens (condensing element) 127. In the illustrated example, the lens 127 is provided, for example, on the second surface 120b of the cylindrical lens array 122. Here, the lens 127 is, for example, a cylindrical lens having a curvature (having a condensing structure) in a plane intersecting the second direction D2 which is the arrangement direction of the channels ch (that is, in a plane intersecting the plane in which the cylindrical lens 122a has a curvature). In other words, the lens 127 is a condensing lens having a refractive power in a plane intersecting the second direction D2 which is the arrangement direction of the channels ch. The lens 127 is arranged so as to be convex toward the side opposite to the light incident surface 102a of the light incident window 102 (convex on the light incident side of the lens 127). In this case, the field of view in a plane intersecting the arrangement direction of the channels can be widened. Note that the lens 127 may be arranged so as to be convex toward the light incident surface 102a side of the light incident window 102 (convex on the light emitting side of the lens 127), or may have a shape that is convex toward both the side opposite to the light incident surface 102a of the light incident window 102 and the light incident surface 102a side of the light incident window 102 (convex on both the light incident side and the light emitting side of the lens 127).

[0088] Further, as shown in FIG. 15, the spectroscope 1 may have a case 200A instead of the case 200. The case 200A is different from the case 200 of the above-described embodiment in that it does not have the protrusion 214. When such a case 200A is used, the electron tube 100 can be easily and highly accurately positioned with respect to the spectroscopic unit 2 by using the assembly jig 300. Hereinafter, the positioning using the assembly jig 300 will be described.

[0089] The assembly jig 300 is formed in a plate shape having a first surface 300a and a second surface 300b on the side opposite to the first surface 300a. The assembly jig 300 is arranged such that the first surface 300a faces (here, contacts) the first surface 201a of the top plate 201.

[0090] In that state, the pin 301 penetrating the assembly jig 300 is inserted into the through hole 212 of the top plate 201, and another pin 302 penetrating the assembly jig 300 is inserted into each of the first through hole 125a and the second through hole 125b of the positioning member 120 through the top plate 201, whereby the electron tube 100, the case 200A, and the assembly jig 300 are mechanically positioned relative to each other. Note that the fixing and positioning to the spectroscopic unit 2 are the same as those of the case 200 in the above-described embodiment. Therefore, by using this assembly jig 300, it is possible to easily and highly accurately position the electron tube 100 relative to the spectroscopic unit 2.

[0091] Here, in the above-described embodiment, the electron tube 100 having the electron multiplier section 110 composed of a semiconductor element such as an HPD has been exemplified. However, the electron tube may be a photomultiplier tube. FIG. 16(a) is a schematic diagram showing an electron tube 100A which is a photomultiplier tube. The electron tube 100A shown in FIG. 16(a) is a photomultiplier tube having a multi-channel (multi-channel PMT). The electron tube 100A has an electron multiplier section 110A, and the electron multiplier section 110A in the present embodiment has a focusing electrode 131, a plurality of dynodes 132, and a plurality of anode electrodes 133.

[0092] The focusing electrode 131 focuses the photoelectrons emitted from the photoelectric conversion section 102s toward the dynode 132. The focusing electrode 131 is arranged so as to face the photoelectric conversion section 102s.

[0093] A plurality of dynodes 132 are provided between the focusing electrode 131 and the plurality of anode electrodes 133. The plurality of dynodes 132 emit secondary electrons in response to the incidence of the photoelectrons focused by the focusing electrode 131 and multiply the secondary electrons. The plurality of dynodes 132 are arranged in multiple stages between the focusing electrode 131 and the plurality of anode electrodes 133 and constitute one channel ch. That is, the electron multiplier section 110A is configured by arranging a plurality of channels ch, each of which is configured by arranging a plurality of dynodes in multiple stages, along the second direction D2. Even in this case, the electron multiplier section 110A is arranged in one direction and has a plurality of channels ch for multiplying each of the electrons emitted from the photoelectric conversion section 102s in response to each of the plurality of lights L2 incident from the light incident window 102.

[0094] As shown in FIGS. 16(b) and 16(c), even in this case, the positioning member 120 can be configured in the same manner as in the above embodiment. A plurality of first reference lines 134 (marking portions), which serve as a reference for aligning the positioning member 120, are drawn on the electron multiplier section 110A (specifically, the focusing electrode 131 in the present embodiment). The second reference line 126 of the positioning member 120 is aligned with the first reference line 134. Therefore, even for the electron tube 100A, which is a photomultiplier tube, it can be easily and highly accurately positioned in the same manner as the electron tube 100. Specifically, by attaching the reference portion 125 of the positioning member 120 to the spectroscopic section 2 using a mechanical reference, the spectroscopic section 2 and the electron tube 100A (and further the internal structure such as the electron multiplier section 110A) can be highly accurately positioned.

[0095] Also, as shown in FIG. 17, the electron tube may be an electron tube 100B, which is a side-incident type photomultiplier tube. The electron tube 100B is a photomultiplier tube having a reflective photocathode. The electron tube 100B has a bulb 401, a grid 402, a photoelectric conversion section 403, a plurality of dynodes 406 (electron multiplier section 110B), and an anode 405.

[0096] The valve 401 houses a grid 402, a photoelectric conversion section 403, a plurality of dynodes 406 (electron multiplier section 110B), and an anode 405. The light L2 is incident into the valve 401 from the side surface 401a of the valve 401 and is supplied to the photoelectric conversion section 403. That is, the portion of the valve 401 facing the photoelectric conversion section 403 functions as the light incident window 102. The grid 402 is a focusing electrode.

[0097] The photoelectric conversion section 403 is a reflective photoelectric surface, for example, a structure in which a photoelectric surface is formed on a base material portion made of metal. The photoelectric conversion section 403 emits photoelectrons e in response to the incident light L2 that has entered through the side surface 401a of the valve 401. The electrons emitted from the photoelectric conversion section 403 are amplified by the plurality of dynodes 406.

[0098] The plurality of dynodes 406 emit secondary electrons in response to the incidence of the photoelectrons e from the photoelectric conversion section 403 and multiply the secondary electrons. The electron multiplier section 110B is constituted by, for example, a plurality (eight in this example) of dynodes 406. Each dynode 406 is formed in a curved shape or a flat plate shape, and emits secondary electrons toward the next-stage dynode 406 due to the collision of the secondary electrons emitted from the previous-stage dynode 406. As a result, the secondary electrons are sequentially multiplied. The multiplied secondary electrons are collected by the anode 405.

[0099] As shown in FIGS. 17 and 18, even in this case, the positioning member 120 can be configured in the same manner as in the above-described embodiment. However, in this case, the first surface 120a of the positioning member 120 is formed to be curved so as to follow the side surface 401a of the valve 401. Thereby, it becomes possible to fix the positioning member 120 to the valve 401 while bringing the first surface 120a of the positioning member 120 into contact with the side surface 401a of the valve 401 that functions as a light incident window. As a result, also in the electron tube 100B, similar to the electron tube 100, it can be positioned easily and with high precision. Specifically, by attaching the reference portion 125 of the positioning member 120 to the spectroscopic unit 2 as a mechanical reference, the spectroscopic unit 2 and the electron tube 100B (further, internal structures such as the electron multiplier unit 110B, for example, in this embodiment, aligning the reference line provided on the base material portion of the photoelectric conversion unit 403 and the reference line provided on the positioning member 120) can be positioned with high precision.

[0100] As described above, the electron multiplier unit 110B may not have a plurality of channels ch. In this case, particularly when the effective area is small, high-precision positioning is required, so this structure is effective.

[0101] Note that the positioning member 120 may not have a lens, and the reference portion 125 may have a single mechanical structure instead of a plurality of mechanical structures such as the first through hole 125a and the second through hole 125b. Further, the optical system 20 of the spectroscopic unit 2 may not have the filter 22, or even if it has the filter 22, it may be in the front stage of the diffraction grating 23, for example, it may be arranged further in the front stage than the collimating lens 21. The antireflection film 120s may not be formed on either the first surface 120a or the second surface 120b of the positioning member 120. Also, the material of the positioning member 120 may be a material having a refractive index close to that of the light incident window 102. Even in this case, the reflection of light in the positioning member 120 can be reduced. Further, the cylindrical lens array (optical element) 122 may be an optical element having a refractive power, and as long as it receives the incidence of the light L2 from the spectroscopic unit 2 and emits the light L2 toward the light incident surface 102a, it may be a single lens that is not arrayed, or a Fresnel lens, a Gradient Index lens, a diffraction lens, or a condenser prism.

Explanation of Reference Numerals

[0102] 1... Spectroscope, 2... Spectroscopic unit (external device), 22... Filter, 23... Diffraction grating, 100, 100A, 100B... Electron tube, 102... Light incident window, 102a... Light incident surface, 102s, 403... Photoelectric conversion unit, 107... Housing, 110, 110A, 110B... Electron multiplication unit, 120... Positioning member, 120a... First surface, 120b... Second surface, 120s... Antireflection film, 122... Cylindrical lens array (optical element), 122a... Cylindrical lens (optical structure), 123... Light passage portion, 123b... Opening, 125... Reference portion, 125d... End face, 127... Lens (condensing element), ch... Channel, L1... Detection light, L2... Light.

Claims

1. An electron tube that is attached to an external device and used, a housing that includes a light incident surface and has a light incident window through which light from the external device is incident; a photoelectric conversion unit that is disposed in the housing so as to face the light incident window and emits electrons in response to the light incident from the light incident window; an electron multiplication unit that is disposed in the housing and multiplies the electrons emitted from the photoelectric conversion unit; a positioning member that is formed separately from the light incident window and fixed to the light incident surface, and has a light passing portion that allows the light from the external device to pass toward the light incident surface; and the positioning member has a reference portion that serves as a reference for mechanical positioning with respect to the external device, an electron tube.

2. The positioning member is fixed to the light incident surface such that the light passing portion faces the photoelectric conversion unit and the light passing through the light passing portion is incident on a desired region of the photoelectric conversion unit. The electron tube according to Claim 1.

3. A mark portion is formed on at least one of the positioning member, a base material portion on which the photoelectric conversion unit is provided, and the electron multiplication unit. The electron tube according to Claim 1.

4. The electron multiplication unit has a plurality of channels that are arranged in at least one direction and multiply each of the electrons emitted from the photoelectric conversion unit in response to each of the plurality of lights incident from the light incident window. The electron tube according to Claim 1.

5. The positioning member has an optical element that is provided in the light passing portion, receives the incidence of the light from the external device, and emits the light toward the light incident surface. The electron tube according to Claim 1.

6. The reference portion has a position reference that serves as a reference for the position with respect to the external device and an angle reference that serves as a reference for the angle with respect to the external device. The electron tube according to Claim 1.

7. The reference portion includes at least one of a protrusion, a hole, a notch, and an end face formed on the positioning member. The electron tube according to Claim 1.

8. The positioning member has a first surface on the light incident surface side and a second surface on the side opposite to the first surface. An antireflection film is formed on at least one of the first surface and the second surface. The electron tube according to Claim 1.

9. An opening for exposing the light incident surface to the outside is formed in the light passing portion. The electron tube according to Claim 1.

10. The positioning member is provided in the light passing portion, and includes an optical element that receives the incidence of the light from the external device and emits the light toward the light incident surface. The optical element includes a plurality of optical structures aligned with each of the plurality of channels. The electron tube according to claim 4.

11. A condensing element is provided on a surface of the optical element opposite to the light incident surface, and has a condensing structure in a plane intersecting the arrangement direction of the channels. The electron tube according to claim 10.

12. A spectroscopic unit as the external device for splitting the detected light into lights of a plurality of wavelengths and emitting the lights, The electron tube according to claim 1, Comprising A spectroscope.

13. The spectroscopic unit is A dispersion element disposed on the optical path of the detected light for splitting the detected light into lights of the plurality of wavelengths, and A wavelength selection element disposed in front of the dispersion element on the optical path of the detected light for reflecting or absorbing light in a specific wavelength band of the detected light, Comprising The spectroscope according to claim 12.

Images