WO2003098658A1

WO2003098658A1 - Photomultiplier tube and its using method

Info

Publication number: WO2003098658A1
Application number: PCT/JP2003/006075
Authority: WO
Inventors: Hisaki Kato; Hideto Kawai; Tsuyoshi Fujimori
Original assignee: Hamamatsu Photonics K.K.
Priority date: 2002-05-15
Filing date: 2003-05-15
Publication date: 2003-11-27
Also published as: JP4173134B2; JPWO2003098658A1; AU2003231505A1

Abstract

A plurality of conductive partitioning members (25) are provided such that each conductive partitioning member (25) is located between two corresponding adjacent anode pieces (21) to partition two adjacent channels. Since the conductive partitioning member (25) has been applied with a potential between the final stage dynode potential and anode potential, electrons emitted from each channel (A) of the final stage dynode (8) can be led appropriately to a corresponding anode piece (21) and emission of electrons from the corresponding anode piece (21) to an adjacent anode piece (21) can be suppressed. Consequently, crosstalk is prevented at the anode and resolution of energy can be enhanced for each channel.

Description

Specification

Photomultiplier tube and method of using the same

The present invention relates to a photomultiplier tube and a method of using the same.

And a method of using the same. Background art

Japanese Patent Application Laid-Open No. HEI 3-180725 proposes a multi-pole detection node structure. In this multi-pole detection anode structure, a plurality of anodes are provided on an insulating substrate, and a split electrode is provided between adjacent anodes. The split electrode is effectively at the same potential as the anode or at a potential higher than the anode potential, and captures electrons arriving between the anodes. Therefore, it is possible to prevent the electron from being incident on the insulator region between the anodes and accumulating the negative charge. This publication states that the potential of the split electrode may be temporarily lower than the anode potential or may be slightly lower continuously if the electrons arriving between the anodes can be captured by the split electrode. Have been.

On the other hand, a multi-anode type photomultiplier tube as shown in FIG. 1 has been conventionally known.

In such a conventional photomultiplier tube 100, a photoelectric surface 103a is formed on the inner surface of the light receiving surface plate 103. The focusing electrode 113 is arranged to face the photocathode 103a. Below the focusing electrode 113, there is provided a stacked electron multiplier 109 in which a plurality of dynodes 108 are stacked. Below the electron multiplication unit 109, a multi-pole type anode 112 is provided. The anode 1 1 2 is composed of a plurality of anode pieces 1 2 1 It is arranged corresponding to the number of channels.

In this example, the electron multiplier 109 has a plurality of channels arranged in a one-dimensional array. That is, in each stage of the dynode 108, a plurality of secondary electron emitting pieces 124 are arranged one-dimensionally in a parallel manner in the X-axis direction. For this reason, also in the anode 112, a plurality of anode pieces 121 are arranged one-dimensionally in a linear manner. Specifically, for example, as shown in FIG. 2 (A) and FIG. 2 (B), the anode piece 1 21 is placed on the anode substrate 120 in parallel to the X-axis direction. They are linearly arranged in a dimension.

When a plurality of channels are arranged in a two-dimensional matrix shape in the electron multiplying unit 109, that is, a plurality of secondary electron emitting pieces 124 are two-dimensionally arranged in the dynodes 108 of each stage. In the case where the anodes 112 are arranged in a matrix form, a plurality of node pieces 121 are arranged in a two-dimensional matrix form also in the anode 112. For example, as shown in FIGS. 3 (A) and 3 (B), a plurality of node pieces 1 2 1 are arranged in a two-dimensional matrix.

In the conventional photomultiplier tube 100 having the above configuration, when light enters the light receiving surface plate 103, electrons are emitted from the photocathode 103a, and the electrons are channeled by the focusing electrode 113. The convergence is performed every time, and multi-stage multiplication is performed for each channel by a plurality of dynodes 108. The electrons multiplied for each channel are collected by the corresponding anode node 121, thereby obtaining an output for each channel.

As described above, if the electron multiplying unit 109 has a stacked channel dynode structure, electrons can be multiply multiplied for each channel. Therefore, the electrons multiplied by the electron multiplying unit 109 rarely reach the anode substrate 120 between the adjacent anode pieces 121. Disclosure of the invention

However, the present inventors have found that in the conventional photomultiplier tube 100 described above, crosstalk occurs between the anode pieces 121 and that the resolution of energy per channel is insufficient. did.

Therefore, the present inventors have considered the electrons emitted from the electron multiplier 109. As a result, the electrons incident on the anode piece 1 2 1 further emit secondary electrons from the anode piece 1 2 1, and the secondary electrons without going to the adjacent anode piece 1 2 1 cause crosstalk. Was discovered.

Therefore, an object of the present invention is to provide a photomultiplier tube and a method of using the same, which solve the above problems, prevent crosstalk at the anode, and improve the resolution of energy for each channel.

In order to achieve the above object, the present invention provides a photocathode which emits electrons when light is incident thereon, and a plurality of dynodes, wherein the plurality of dynodes are arranged in a first stage from the photocathode side. From the first stage to the last stage, the dynodes in each stage define a plurality of channels, and multiply multiply the electrons emitted from the photocathode for each corresponding channel by a multi-stage channel dynode unit. And a plurality of anode electrodes facing the final dynode and one-to-one corresponding to the plurality of channels, and multi-stage multiplication by the plurality of channels of the stacked channel dynode portion. A node for transmitting an output signal for each channel based on the obtained electrons, and a plurality of conductive partition members opposed to the final dynode, and each conductive partition member has a corresponding one. A predetermined anode potential applied to each anode electrode and a predetermined anode potential applied to the final stage dynode are provided between two adjacent node electrodes. Last stage dynode And a shielding electrode to which an electric potential between the electric potential and the electric potential is applied.

In the photomultiplier tube of the present invention having such a configuration, a voltage is applied to the photocathode, the first to final dynodes, and the anode such that the potential increases in order from the photocathode toward the anode. Is done. Therefore, the anode potential applied to the anode electrode is higher than the final dynode potential applied to the final dynode. When light enters an arbitrary position on the photocathode, electrons are emitted from that position on the photocathode. The electrons are multiplied by a corresponding number of channels in the first to final dynodes, and emitted from the final dynode.

Here, a conductive partition member is provided between each two adjacent anode electrodes so as to partition each two adjacent channels. Then, a potential between the anode potential and the final dynode potential, that is, a potential higher than the final dynode potential and lower than the anode potential is applied to the conductive partition member. For this reason, electrons emitted from an arbitrary channel of the final dynode can be made incident only on the corresponding anode electrode, and from the anode electrode according to the incidence of electrons on the corresponding anode electrode. Emission of secondary electrons can be suppressed. Therefore, crosstalk at the anode can be prevented, and the energy resolution of each channel can be improved.

More specifically, on both sides of each anode electrode, two conductive partition members to which a potential higher than the final dynode potential is applied are arranged. As a result, electrons emitted from any channel of the final dynode are electrically attracted to the two conductive partition members arranged on both sides of the corresponding anode electrode, and the corresponding electric potential of the higher potential is further increased. It is led to the anode electrode. This ensures that the electrons from each channel respond To the anode electrode. Therefore, crosstalk between the anode electrodes can be prevented, and the resolution of each channel can be improved.

Moreover, since the potential of the conductive partition member is lower than the anode potential, when the electrons reach the anode electrode, the electrons are less likely to be emitted from the anode electrode. Even if electrons are emitted from the anode electrode, the emitted electrons are electrically pushed back by the low potential of these two conductive partition members disposed on both sides of the anode electrode. Therefore, the emitted electrons cannot reach the anode electrode adjacent to the conductive partition member ゃ and return to the original anode electrode. Thus, in the present invention, the emission of electrons from the anode electrode is suppressed, that is, the electrons are hardly emitted from the anode electrode, and even if they are emitted, the emitted electrons are surely returned to the anode electrode. Can be. Therefore, crosstalk between the anode electrodes can be reliably prevented.

Here, it is preferable that each conductive partition member has a size that shields between adjacent anode electrodes so that electrons emitted from the anode electrode cannot enter the adjacent anode electrode. For example, the height of the conductive partition member extending toward the final dynode is higher than the height of each anode electrode extending toward the final dynode, and the adjacent anode electrode cannot be seen from each anode electrode. It would be good if each anode electrode could not directly look directly at the adjacent anode electrode. Even if electrons are emitted from the anode electrode, it is possible to prevent the electrons from being incident on the adjacent anode electrode.

Further, each conductive partition member is connected to each channel of the final stage dynode so that electrons emitted from each channel of the final stage dynode cannot enter the adjacent anode electrode. It is preferable that the size is such that it can shield the anode electrode adjacent to the corresponding anode electrode. For example, the height of the conductive partition member extending toward the final dynode may be such that each channel of the final dynode cannot see through the anode electrode next to the corresponding anode electrode, that is, directly on a straight line. The size should be such that it cannot be desired. Specifically, each die node has a plurality of secondary electron emitting pieces, and a height force extending toward the last-stage dynode of the conductive partition member is such that the upper end portion of the conductive partition member is the lowest. The size should be close to the lower end of the corresponding secondary electron emission piece of the final stage dynode, so that the anode electrode of the adjacent channel cannot be seen through each channel of the final stage dynode. Electrons emitted from each channel of the final dynode can be prevented from entering the anode electrode of the next channel.

The value of the potential to be applied to the conductive partition member is an intermediate value between the value of the anode potential and the value of the final dynode potential, and the electrons emitted from each channel of the final dynode correspond to the corresponding anode. It is preferable that the value is within a range that can appropriately enter the single electrode and that can prevent the electron from directly or indirectly entering the conductive partition member located on both sides of the anode electrode.

When a potential higher than the anode potential is applied to the conductive partition member, the electrons emitted from the final dynode are not directed to the corresponding anode electrode but to one of the conductive partition members located on both sides of the anode electrode. It is directly incident and the output of the anode electrode decreases. In addition, even if electrons emitted from the final-stage diode correctly enter the anode electrode, secondary electrons are emitted from the anode electrode with the incidence, and the secondary electrons are electrically transferred to the conductive partition member having a potential higher than the anode potential. Attracted and enter the conductive partition I shoot. Also in this case, the output of the anode electrode decreases. If a potential equal to the anode potential or a potential lower than the anode potential but smaller than the anode potential is applied to the conductive partition member, the electrons emitted from the final stage dynode will still be conductive. There is a possibility that the light is directly incident on the partition member and the output of the anode electrode is reduced. Also, even if electrons emitted from the final dynode enter the anode electrode correctly, the potential difference between the anode potential and the potential of the conductive partition member is smaller than the energy (emission speed) of secondary electrons generated at the anode electrode. Due to its small size, the emission of secondary electrons cannot be suppressed. Therefore, also in this case, secondary electrons are emitted from the anode electrode and reach the conductive partition member or the adjacent anode electrode. Then, the output of the anode electrode decreases. When secondary electrons reach the adjacent anode electrode, crosstalk also occurs.

On the other hand, conversely, when a potential is applied to the conductive partition member that is sufficiently lower than the anode potential and has a small difference from the final-stage dynode potential, electrons emitted from the final-stage dynode become conductive. Due to the influence of the electron lens generated by the partition member, the light cannot enter the corresponding anode electrode.

Therefore, the difference between the potential applied to the conductive partition member and the potential of the final dynode is large enough to allow electrons emitted from each channel of the final dynode to appropriately enter the corresponding anode electrode. The difference between the potential applied to the partition member and the anode potential is such that electrons emitted from each channel of the final dynode enter the conductive partition members located on both sides of the corresponding anode electrode, and It is preferable that the electrode has a size that prevents secondary electrons generated at the anode electrode from entering the adjacent anode electrode of the corresponding anode electrode. For example, the potential to be applied to the conductive partition member is higher than the final stage dynode potential, lower than the anode potential, and the difference between the anode potential and the anode potential is about 5% or more of the difference between the anode potential and the final stage dynode potential. Preferably, the potential is such that it is within about 70% or less. For example, when the anode potential is 0 volts and the final dynode is a predetermined negative potential, the conductive partition member has a negative potential, and its absolute value is the absolute value of the potential of the final dynode. A potential within a range of about 5% or more and about 70% or less of the value may be applied. For example, when a potential is applied such that the difference between the potential applied to the conductive partition member and the anode potential is about half of the difference between the anode potential and the final-stage dynode potential, that is, about 50%. good.

Here, it is preferable that the anode further includes an anode substrate made of a ceramic substrate, and a plurality of anode electrodes are provided on the anode substrate in a one-to-one correspondence with a plurality of channels. Preferably, the shielding electrode further includes a frame-shaped member, and the plurality of conductive partition members are formed integrally with the frame-shaped member. In this case, simply placing the shielding electrode on the anode substrate such that each conductive partition member is located between two corresponding adjacent anode electrodes, the anode electrode and the conductive partition member can be easily connected to each other. Can be arranged at an appropriate position.

In the case where a plurality of channels are arranged in one direction in the laminated channel dyno, the plurality of anode electrodes are also arranged one-dimensionally substantially in parallel to the direction. Therefore, each conductive partition member is provided between the corresponding two adjacent anode electrodes in the one-dimensional direction. On the other hand, when a plurality of channels are arranged in a two-dimensional matrix, a plurality of anode electrodes are also arranged in a two-dimensional matrix. Therefore, each conductive partition member is provided between two corresponding adjacent anode electrodes in each of the two-dimensional directions. Here, the photomultiplier tube of the present invention is provided between the anode and the last-stage dynode, has a plurality of converging pieces, and each two adjacent converging pieces have one opening therebetween. By defining a plurality of openings, the electrons emitted from each channel of the final stage dynode are converged at the corresponding opening and guided to the corresponding anode electrode, thereby emitting from the final stage dynode. It is preferable to further include a converging electrode for converging the obtained electrons for each channel.

In this case, a potential is applied to the focusing electrode to form an electron lens for focusing electrons emitted from each channel of the final dynode and guiding the electrons to the corresponding anode electrode. For example, it is preferable that substantially the same potential as the final-stage dynode potential is applied to the focusing electrode. With such a focusing electrode, electrons emitted from an arbitrary channel of the final dynode can be reliably guided to the corresponding anode electrode, and crosstalk can be more reliably prevented. In addition, since the intermediate potential between the dynode potential and the anode potential at the final stage is applied to the conductive partition member, the emission of electrons from the anode electrode can be reliably suppressed, and the crosstalk is reduced. Further, it is possible to surely prevent the occurrence.

Here, the photomultiplier tube of the present invention is provided between the photocathode and the stacked-type channel dynode part, has a plurality of different converging pieces, and each of two adjacent converging pieces is adjacent to each other. In the meantime, a plurality of openings are defined by defining one opening, and electrons emitted from an arbitrary position on the photocathode are converged at the corresponding opening to correspond to the corresponding one of the stacked channel dynodes. It is preferable to further include another focusing electrode that guides the electron emitted from an arbitrary position on the photocathode to each channel by guiding the channel to the channel. For example, it is preferable that substantially the same potential as that of the photocathode is applied to the other focusing electrode. As described above, if another focusing electrode for focusing electrons for each channel is provided between the photocathode and the stacked channel dynode portion, electrons emitted from an arbitrary position on the photocathode can be more reliably. , Can be led to the corresponding channel of the stacked channel dynode.

It is preferable that the photomultiplier tube of the present invention further includes a light receiving surface plate and a wall portion formed of, for example, a side tube and a stem for forming a vacuum region together with the light receiving surface plate. In this case, the photocathode is formed inside the vacuum region on the inner surface of the light-receiving surface plate, and the stacked channel dynode part, the anode, the shielding electrode, and the focusing electrode are provided inside the vacuum region. For this reason, when light passes through the light receiving surface plate and enters an arbitrary position on the photoelectric surface, electrons are emitted from the position on the photoelectric surface. The electrons are multiplied in the corresponding channel to generate an output signal of the corresponding channel.

In addition, a light-absorbing glass partition is provided in the light-receiving surface plate corresponding to each channel, and a light-collecting device corresponding to each channel is provided on the outer surface of the light-receiving surface plate. The light is applied to the surface of each secondary electron emission piece that defines each channel of the first and second dynodes from the photocathode side of the multi-stage dynode. Performing a reflection process, further increasing the length of each converging piece that defines each channel of the other converging electrode, and setting the respective channels of the die nodes located at the first and second stages. By preventing the light reflected on the surface of each of the secondary electron emitting pieces from returning to the adjacent channel position in the photocathode, the crosstalk of light is also suppressed, and the resolution is improved. It is possible to further improve.

Further, the present invention has a photoelectric surface that emits electrons by the incidence of light, and a plurality of dynodes, wherein the plurality of dynodes are arranged from the first surface to the last stage from the photoelectric surface side. The dynos are arranged in this order, A plurality of channels defines a plurality of channels, and a stacked channel dynode section for multiplying the electrons emitted from the photocathode for each corresponding channel in multiple stages, and a plurality of anode electrodes are opposed to the final stage dynode. And, in a one-to-one correspondence with the plurality of channels, an output signal for each channel is transmitted based on the electrons multiplied by the plurality of channels in the plurality of channels of the stacked channel dynode unit. And a shielding electrode provided between a pair of adjacent anode electrodes, each of which includes a plurality of conductive partition members facing the final stage of the dynode. A predetermined anode potential is applied to each anode electrode, a predetermined final dynode potential is applied to the final dynode, and each of the conductive partition members is provided. Further, there is provided a method of using a photomultiplier tube, characterized in that a potential between the anode potential and the final stage node potential is applied.

In the method of using the photomultiplier tube according to the present invention having such a configuration, the photocathode and the first to final dynodes and the anode are connected to each other so that the potential increases gradually from the photocathode to the anode. On the other hand, a voltage is applied. The potential applied to the conductive partition member is higher than the final dynode potential and lower than the anode potential. For this reason, electrons emitted from an arbitrary channel of the final dynode are made incident on the corresponding anode electrode, and secondary electrons are emitted from the anode electrode in response to the incidence of electrons on the corresponding anode electrode. Can be suppressed from being released. Therefore, it is possible to prevent crosstalk at the node and to improve the resolution of the energy storage for each channel.

Here, the difference between the potential applied to the conductive partition member and the potential of the final dynode is a magnitude that allows electrons emitted from each channel of the final dynode to appropriately enter the corresponding anode electrode. Having the conductivity The difference between the potential applied to the conductive partition member and the anode potential indicates that electrons emitted from each channel of the final stage dynode enter the conductive partition member located on both sides of the corresponding anode electrode. And having a size to prevent secondary electrons generated at the ground electrode from being incident on the ground electrode adjacent to the corresponding ground electrode. preferable. Therefore, crosstalk between the anode electrodes can be reliably prevented. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a cross-sectional view of a conventional photomultiplier tube.

FIG. 2 (A) is a plan view showing an example of a state in which a plurality of anode pieces are arranged on a substrate in the photomultiplier tube of FIG. 1, as viewed from the electron incident direction.

FIG. 2 (B) is a cross-sectional view taken along the line IIB_IBB ′ in FIG. 2 (A).

FIG. 3A is a plan view showing an example of a state in which a plurality of anode pieces are arranged on a substrate in a modified example of the photomultiplier tube in FIG. 1, as viewed from the electron incident direction. is there.

FIG. 3 (B) is a cross-sectional view taken along a line IIIB-IIIB 'in FIG. 3 (A).

FIG. 4 is a cross-sectional view of the photomultiplier according to the first embodiment of the present invention.

FIG. 5 (A) is a plan view of the photomultiplier tube of FIG. 4 showing a state in which a shielding electrode and a plurality of anode pieces are arranged on a ceramic substrate, as viewed from the electron incident direction. .

FIG. 5 (B) is a sectional view taken along line VB-VB ′ in FIG. 5 (A). FIG. 6 is a graph showing a change in anode output when the potential supplied to the shielding electrode in the photomultiplier tube of FIG. 4 was changed.

FIG. 7 (A) is a plan view of the modified example of the photomultiplier tube of FIG. 4, showing a state where the shield electrode and a plurality of anode pieces are arranged on the ceramic substrate, as viewed from the electron incident direction. FIG.

FIG. 7 (B) is a cross-sectional view taken along the line VIIB-VIIB ′ in FIG. 7 (A).

FIG. 8 is a sectional view of a photomultiplier according to a second embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a photomultiplier according to an embodiment of the present invention and a method for using the same will be described with reference to the drawings.

(First Embodiment)

A photomultiplier tube according to a first embodiment of the present invention and a method of using the same will be described with reference to FIGS. 4 to 7 (B).

As shown in FIG. 4, the photomultiplier tube 1 according to the present embodiment has a substantially rectangular tube-shaped metal side tube 2. The direction of the metal tube 2 is defined as the Z axis. The axis perpendicular to the Z axis and parallel to the plane of FIG. 4 is the X axis. An axis perpendicular to the X axis and the Z axis and perpendicular to the plane of FIG. 4 is defined as the Y axis. A light-receiving surface plate 3 made of glass is fixed to an open end on one side in the tube axis direction of the side tube 2. On the inner surface of the light receiving surface plate 3, a photoelectric surface 3a for converting light into electrons is formed. Photocathode 3 a are those formed by reacting Al force Li metal vapor § Nchimon which had been previously deposited on the light receiving plate 3 _c also the other side of the side tube 2 tube axial opening At the end, a flange portion 2a is formed. The periphery of the metal stem 4 is connected to the flange 2a by resistance welding. It is fixed by contact. Thus, the sealed vessel 5 is constituted by the side tube 2, the light receiving face plate 3, and the stem 4.

A metal exhaust pipe 6 is fixed to the center of the stem 4. The exhaust pipe 6 is used to evacuate the inside of the sealed container 5 by a vacuum pump (not shown) after the assembling work of the photomultiplier tube 1 and to make the inside of the sealed vessel 5 into a vacuum state. It is also used as a tube for introducing metal vapor into the sealed container 5 during formation. A plurality of stem pins 10 are provided to penetrate stem 4. The plurality of stem pins 10 include a plurality of dynode stem pins 10, a plurality of anode pin stem pins, and one shield electrode stem pin.

Inside the sealed container 5, a block-type laminated electronic multiplier 7 is fixed. The electron multiplier 7 has an electron multiplier 9 in which ten (10) dynodes 8 are stacked. The dynode 8 is made of, for example, stainless steel. The electron multiplier 7 is supported in the sealed container 5 by a plurality of stem pins 10 provided on the stem 4. Each dynode 8 is electrically connected to the corresponding dynode stem pin 10.

Further, the electron multiplier 7 has a flat first focusing electrode 13 arranged between the photocathode 3 a and the electron multiplier 9. The first focusing electrode 13 is also made of, for example, stainless steel. The first focusing electrode 13 has a plurality of linear focusing pieces 23 arranged in parallel with each other. A slit-like opening 13a is formed between adjacent converging pieces 23. Therefore, the plurality of openings 13a force S are linearly arranged in one direction (a direction parallel to the X axis).

The electron multiplier 9 is a stacked channel dynode in which a plurality of dynodes 8 are stacked. In this example, the electron multiplier 9 has dynodes 8 (dynode D vl to dynode D yl O) of 10 stages in total and the photocathode 3 a The layers are stacked in this order from the side to the node 12 described later. Here, each stage of dynode 8 (dynode D yi (where i is an integer of 1 or more and 10 or less)) is composed of a plurality of linear secondary electron emitting pieces 24 arranged in parallel with each other. A slit-like electron multiplying hole 8a is formed between the adjacent secondary electron emitting pieces 24. Therefore, a plurality of dynodes 8 (D yi) of each stage have The same number of slit-like electron multiplying holes 8 in section 13a) are arranged linearly in one direction (direction parallel to the X axis).

Each electron multiplying path L is defined by arranging the electron multiplying holes 8a of the dynodes 8 (Dyl to DylO) in all stages in a stepwise direction. Each electron multiplying path L and each opening 13 a of the focusing electrode plate 13 are in one-to-one correspondence, and one channel A is defined. Therefore, a plurality of channels A are defined by the plurality of openings 13 a of the converging electrode plate 13 and the plurality of electron multiplying holes 8 a in each stage of the electron multiplier 9. These multiple channels A are linearly arranged in one direction (a direction parallel to the X axis).

At the lowermost part of the electron multiplier 7, a multi-pole type flat node 12 is arranged so as to face the final stage dynode 8 (dynode D y 10). In this anode 12, as shown in FIGS. 4, 5 (A), and 5 (B), a plurality of rod-shaped anode nodes 21 are connected to a plurality of final dynodes 8 (D y 10). It is arranged on the ceramic substrate 20 so as to correspond to the channel A on a one-to-one basis. As described above, the anode 12 has a reflow structure in which the plurality of anode pieces 21 are linearly arranged in the negative direction (the direction parallel to the X axis). Each anode piece 21 is made of, for example, stainless steel (SUS). Each anode piece 21 is connected to a corresponding anode stem pin 10. With such a configuration, individual outputs can be extracted to the outside via the anode stem pins 10. Has become.

In the present embodiment, as shown in FIG. 4, FIG. 5 (A) and FIG. 5 (B), a flat shielding electrode 15 is formed on the ceramic substrate 20 of the anode 12. Are located in The shielding electrode 15 is made of a conductive material. In this example, the shielding electrode 15 is made of stainless steel. The shielding electrode 15 may be made of a metal such as nickel, iron nickel (alloy), and aluminum. The shielding electrode 15 is composed of a frame plate 22 and a plurality of linear conductive partition members 25 formed integrally with the frame plate 22 and arranged in parallel with each other. . A slit-like opening 15a is formed between adjacent conductive partition members 25. The shielding electrode 15 having such a configuration is oriented such that the plurality of conductive partition members 25 and the plurality of openings 15 a are arranged in a direction in the direction (parallel to the X axis). In addition, they are arranged on the ceramic substrate 20 such that one anode piece 21 is located in each opening 15a. For this reason, each conductive partition member 25 is located between the corresponding two adjacent anode pieces 21 so as to partition adjacent channels A.

As shown in FIG. 5 (B), each conductive partition member 25 is provided between adjacent anode pieces 21 so that electrons emitted from the anode piece 21 cannot enter the adjacent anode piece 21. It is shaped and sized to shield. Specifically, the sectional height of the conductive partition member 25 in the tube axis direction (Z-axis direction) (the direction of the corresponding secondary electron emission piece 24 at the final stage dynode 8 (dynode D y10)) The cross-sectional height of each node piece 21 in the tube axis direction (the cross-sectional height of the final dynode 8 (dynode D y10) extending in the direction of the corresponding channel A) zl It is higher than 2. As a result, each anode piece 21 cannot see through the adjacent anode piece 2 1, that is, each anode piece 2 1 Cannot be directly desired in a straight line. Therefore, even if secondary electrons are emitted from the anode piece 21, it is possible to prevent the secondary electrons from being incident on the adjacent anode piece 21.

In addition, as shown in FIG. 4, each conductive partition member 25 is adjacent to the anode piece 21 to which the electrons emitted from each channel A of the final dynode 8 (dynode Dy10) correspond. The shape and size are such that each channel A of the last dynode 8 and the anode piece 21 adjacent to the corresponding anode piece 21 are shielded so that the input cannot be input to the anode piece 21 of the final stage. It is to increase the tube axis direction of the section height _Z 1 of the conductive partition member 2 5, by approaching the upper end to the corresponding secondary lower end of the electron-emitting element 2 4 of the final stage dynode 8, each The channel A adjacent to the corresponding channel A of the last dynode 8 from the anode piece 21 cannot be seen. In other words, the anode piece 21 of the adjacent channel A cannot be seen from each channel A of the last dynode 8. That is, each channel A of the final stage dynode 8 cannot directly desire the anode piece 21 of the adjacent channel A on a straight line. For this reason, it is possible to prevent electrons emitted from each channel A of the final dynode 8 (Dy10) from being incident on the anode node 21 of the adjacent channel A.

As described above, according to each of the conductive partition members 25 having the above-described cross-sectional height z1, the electrons from each channel A of the final-stage dynode 8 are input to the anode piece 21 of the adjacent channel. In addition, it is possible to prevent electrons emitted from the anode piece 21 from being incident on the adjacent anode piece 21.

Here, in the present embodiment, each anode piece 21 has a rod shape with a circular cross section, and the diameter of the cross section (that is, the height z 2 in the tube axis direction) is 0.35 mm. . On the other hand, each conductive partition member 25 has a rod shape having a rectangular cross section. And its cross-sectional height (that is, height in the tube axis direction) z 1 is 0.5 ram. The distance between the upper end of each conductive partition member 25 and the lower end of the secondary electron emission piece 24 of the final stage dynode 8 (Dy10) is 0.15 mm. However, each node piece 21 does not have to have a circular cross section as described above. For example, each anode piece 21 can have any cross-sectional shape, such as a rectangular cross-section as shown in FIG. 2 (B). Also, each of the conductive partition members 25 is not limited to the above-described rectangular cross-section, but may have any cross-sectional shape. As described above, the electron multiplier 7 has a plurality of channels A linearly arranged. The electron multiplier 9, the anode 12, and the shield electrode 15 in the electron multiplier 7 are provided with predetermined voltage from a voltage application device 60 composed of a bleeder circuit (not shown) via a stem pin 10. Voltage is supplied. Here, the same potential voltage (for example, a negative potential) is applied to the photocathode 3 a and the focusing electrode plate 13. The dynodes 8 and anodes 12 of all 10 stages of the electron multiplier 9 are connected from the first stage closest to the photocathode 3 a to the 10th stage closest to the anode 12, and further to the anode 12. The voltage is applied so that the potential gradually increases. For example, when 180 volts is applied to the photocathode 3a and the anode piece 21 of the anode 12 is set to 0 volt, the dynodes 8 (Dyl to Dyl) in the first to tenth stages are used. O) is applied with a potential that sequentially increases from 800 V (800) Z ll = about 72.7 volts. Specifically, the first stage dynode 8 (D y 1) has about 1 72.3 Porto, the second stage dynode 8 (D y 2) has about 1 64.6 Porto, ··· And the final stage (stage 1) Dynode 8 (D y10) is applied with approximately 12.7 ports. As will be described later, the shielding electrode 15 has an intermediate potential between the final stage dynode 8 (DylO) and the anode 12, for example, one (800) Z 1 half of 1 volt = about 1 36. Four bolts are applied. In the light-receiving surface plate 3, a plurality of partitions (slits) 26 made of light-absorbing glass are embedded so as to correspond to the plurality of channels A on a one-to-one basis. That is, each partition part 26 is provided at a position corresponding to the focusing piece 23 of the first focusing electrode 13. As a result, the inside of the light receiving face plate 3 is partitioned for each channel A by the partitioning part 26, and crosstalk of light in the light receiving face plate 3 is appropriately prevented. The partition 26 is provided with, for example, a colored (for example, black) thin glass sheet, which allows light to be absorbed.

Further, a light collecting member 30 is fixed to the outer surface 29 of the light receiving face plate 3a with an adhesive. The light collecting member 30 is for ensuring that external light is incident on each channel A. More specifically, the light collecting member 30 is composed of a plurality of (that is, the number of channels A) glass light collecting lens portions 32. Each condenser lens section 32 has one convex lens surface 31. The plurality of condenser lens portions 32 are fixed to the outer surface 29 of the light receiving face plate 3a in a state of being arranged in one direction (a direction parallel to the X axis). The condensing member 30 having such a structure can surely make external light incident on the photocathode 3a while condensing light from the outside between the partitions 26 by the convex lens surface 31. Therefore, the light condensing property is enhanced, and at the same time, measures against light crosstalk are ensured. In addition, a light guide such as an optical fiber may be used as the light collecting member 30.

In addition, an oxide film (not shown) is formed on the surface of each converging piece 23 of the first converging electrode 13 so as to eliminate light reflection on each converging piece 23. Therefore, even if the light transmitted through the light receiving surface 3 further exits the photocathode 3 a and enters one of the converging pieces 23, this light is prevented from being reflected by the converging piece 23. . Because of this, such reflection By returning the light to the photocathode 3a, it is possible to prevent unnecessary electrons from being emitted from the photocathode 3a to cause crosstalk of light. Thus, the first focusing electrode 13 functions as an anti-reflection mesh.

In addition, of the 10-stage dynodes 8 arranged in a multi-stage manner, the secondary of each of the first-stage and second-stage dynodes 8 (Dyl, Dy2) on the photocathode 3a side is used. The electron emission pieces 24 are at positions where they can be seen when viewed from the photocathode 3a side, while the dynodes 8 (Dy3 to Dy10) of the other stages have electron multiplication paths L Cannot be seen from the photocathode 3a side. Therefore, there is a possibility that the light exiting from the photocathode 3a will be incident on each of the secondary electron emitting pieces 24 of the first and second dynodes 8 (Dyl, Dy2). For this reason, an oxide film (not shown) is also formed on the surface of the secondary electron emission piece 24 of the first and second stage die nodes 8, and the reflection of light at these is eliminated. The unnecessary cross-talk of light is prevented by preventing unnecessary electrons from being emitted from the photocathode 3a due to the reflected light. The focusing piece 23 of the first focusing electrode 13 and the first and second stage dynodes 8 are subjected to light non-reflection treatment by using, for example, black aluminum instead of an oxide film. A light absorbing material may be formed by vapor deposition or the like.

Further, the length of each converging piece 23 of the first converging electrode 13 in the tube axis direction is increased, and the upper part of each converging piece 23 is brought close to the photocathode 3a. The position of the next channel in the photocathode 3a cannot be seen from the surface of the secondary electron emission piece 24 of each channel A of the second dynode 8 (Dyl, Dy2). ing. Therefore, the surface of the secondary electron emission piece 24 of each channel A of the first-stage and second-stage die nodes 8 is linearly aligned with the adjacent channel position in the photocathode 3a. You can't want directly above. For this reason, even if the light is slightly reflected on the surface of the secondary electron emission piece 24 of the first and second stage die nodes 8, the light is reflected next to the photocathode 3a. Return to the channel position is prevented, and optical crosstalk is more reliably prevented. By increasing the length of each converging piece 23 in the tube axis direction, the lower part of each converging piece 23 may also be made to approach the first-stage die node 8 (Dy1). good.

In the photomultiplier tube 1 of the present embodiment having the above structure, the light transmitted through the light receiving surface plate 3 is converted into electrons when incident on an arbitrary position on the photocathode 3a, and the electrons are converted into the corresponding channel A Will be incident inside. Even if a part of the light incident on the photocathode 3a exits the photocathode 3a, this light is reflected by the first focusing electrode 13 and the first and second dynodes 8. Also, even if the light is reflected by the first and second dynodes 8, it is blocked by the converging piece 23 of the converging electrode 13 and returns to the channel A adjacent to the photocathode 3a. Is prevented. Therefore, unnecessary electrons are prevented from being emitted from the photocathode 3a, and light crosstalk is prevented. Electrons converted from light at any position on the photocathode 3a first pass through the corresponding aperture 13a in the first focusing electrode 13 in the corresponding channel A, where they are converged. You. Further, while passing through the corresponding electron multiplying path L in the electron multiplying unit 9, the light is multiplied by all the dynodes 8 in all stages and is emitted from the corresponding channel A of the final dynode 8. The electrons multiplied by the multi-stage and emitted from the corresponding channel A of the final dynode 8 enter the corresponding anode piece 21. As a result, a predetermined output signal that individually indicates the amount of light that has entered the corresponding position of the light receiving face plate 3 is output from the node piece 21 of the predetermined channel A.

Here, the electron multiplier 9 is a stacked channel dynode: Most of the electrons emitted from the secondary electron emitting pieces 24 of the final stage die fly on the path toward the corresponding anode piece 21. In addition, a potential between the potential of the anode piece 21 and the potential of the final dynode 8 (Dy 10) is applied to the shield electrode 15, that is, the conductive partition member 25. For this reason, the electrons emitted from the final dynode 8 (Dy 10) are electrically pulled by the conductive partition members 25 provided on both sides of the corresponding anode piece 21, and have a higher potential. It is definitely led to the corresponding node piece 21.

Here, when the electrons reach the anode piece 21, the anode piece 21 may emit secondary electrons. However, such secondary electrons are electrically suppressed by the lower-potential conductive partition members 25 provided on both sides of the anode piece 21. Therefore, secondary electrons are hard to be emitted from the anode piece 21. Also, even if released, it cannot reach the conductive partition member 25 or the other anode piece 21 and is returned to the original anode piece 21.

Hereinafter, the relationship between the potential (shield potential) to be applied to the shield electrode 15, the anode potential, and the final dynode potential will be described in more detail. If the conductive partition member 25 has a higher potential than the anode piece 21, much of the electrons from the final dynode 8 directly enter the conductive partition member 25, and the output of the anode piece 21 is output. The sensitivity decreases. Even if some of the electrons from the final dynode 8 (Dy10) enter the anode piece 21 correctly, secondary electrons are emitted from the anode piece 21 with the incidence, and the anode potential It is electrically attracted to the high-potential conductive partition member 25 and is incident on the conductive partition member 25, and the output of the anode is reduced.

Also, whether the potential of the conductive partition member 25 is the same as that of the anode piece 21, Alternatively, when the difference from the anode potential is smaller than the potential of the anode piece 21, a part of the electrons from the final-stage dynode 8 (Dy 10) directly enter the conductive partition member 25. As a result, the anode output will be low. Even if the electrons from the final stage dynode 8 properly enter the corresponding anode piece 21, the energy (emission speed) of the secondary electrons generated by the anode piece 21 at the time of this incidence is reduced. Is larger than the difference between the potential of the conductive partition member 25 and the potential of the anode piece 21, the secondary electrons are emitted from the anode piece 21 and the conductive partition member 25 or the adjacent anode is discharged. It is incident on piece 21. Due to such emission of secondary electrons, the output sensitivity of the anode piece 21 decreases. Also, when a secondary electron is incident on the adjacent node piece 21, crosstalk occurs.

On the other hand, if the potential of the conductive partition member 25 is lower than the potential of the anode piece 21 and the difference between the potential of the anode piece 21 and the potential of the anode piece is large to some extent, the electrons from the final dynode 8 (Dy10) are discharged. However, it can be appropriately incident on the corresponding node piece 21. Moreover, the energy (emission speed) of the secondary electrons generated at the anode piece 21 at the time of the incidence is smaller than the difference between the potential of the conductive partition member 25 and the potential of the anode piece 21, Secondary electrons can be confined to the anode piece 21. That is, secondary electrons are hardly emitted from the anode piece 21, and even if they are emitted, they can be pushed back to the anode piece 21.

However, when the potential of the conductive partition member 25 becomes sufficiently lower than the anode potential and becomes close to the final stage node potential, the electron lens effect generated by the conductive partition member 25 causes the final stage dynode. Electrons from 8 will not be properly directed to the corresponding channel anode piece 21.

Therefore, the voltage to be applied to the conductive partition member 25 (shielding electrode 15) The potential is an intermediate potential between the final dynode potential and the anode potential, and the conductive partition member 25 appropriately transfers the electrons output from each channel A of the final dynode 8 to the corresponding anode node 21. The distance is set so that the electrons can be guided and the electrons emitted from the final dynode 8 or the electrons emitted from the anode piece 21 do not enter the conductive partition member 25. For example, the potential of the shielding electrode 15 may be set so that the difference between the anode potential and the anode potential is within the range of about 5% or more and about 70% or less of the difference between the anode potential and the final dynode potential. preferable.

(Experiment)

The present inventors conducted an experiment for examining a preferable range of a voltage to be applied to the shielding electrode 15, that is, each conductive partition member 25.

In this experiment, too, 180 V was applied to the photocathode 3a of the photomultiplier tube 1, the anode 12 was set to 0 V, and the dynodes 8 (Dyl to Dyl O ), A potential was sequentially increased from −800 V by (800) Z ll = approximately 72.7 V. Therefore, a voltage of 1 (800) / 1 1 = -72.7 V was applied to the last dynode 8.

Then, the potential (shield potential) of the shield electrode 15 (that is, each conductive partition member 25) is changed between 170 V and 170 V, and how the output of the anode changes. I checked.

FIG. 6 is a graph showing a change in anode output obtained as a result of changing the potential of the shielding electrode 15. Here, the positive anode output current indicates that the number of electrons emitted from the anode piece 21 is larger than the number of electrons incident on the anode piece 21 from the last dynode 8. Conversely, a negative anode output current indicates that electrons entering the anode piece 21 from the final dynode 8 are properly absorbed by the anode piece 21. As is clear from this graph, when the voltage of the shielding electrode 15 is about 20 V, the maximum output is obtained from the anode piece 21, and the voltage of the shielding electrode 15 is about 150 V or more and about 15 V. In the following cases, the output within the allowable range (more than 80% of the maximum output) was obtained with the anode piece 21.

From the above experiment, when the electron multiplier 9 is provided with a dynode 8 having a 10-stage configuration, 180 ports were applied to the photocathode 3a and OV was applied to the anode 12, and the 1st stage to the 1st stage were applied. When applying a potential that increases in steps of (800) Z 11 = approximately 72.7 volts sequentially from 180 ports to the dynode 8 of the 10th stage, the conductive partition member 25 That is, it is preferable that, for example, a potential in a range of about 150 volts or more and about 15 portes or less is applied to the shielding electrode 15 as an intermediate potential between the final dynode 8 and the anode 12. I understood. For example, a potential of 1 (800) / half of 11 volts = approximately 1364 volts may be applied.

In addition, when an experiment was performed by applying a potential of 136.4 volts to the shielding electrode 15, it was confirmed that crosstalk was reduced and the resolution of each channel was improved.

As described above, the photomultiplier tube 1 of the present embodiment has the photocathode 3 a that emits electrons by light incident on the light-receiving surface plate 3, and emits electrons emitted from the photocathode 3 a for each channel. A first convergence electrode 1 for converging electrons for each channel between the photocathode 3a and the electron multiplier 9 between the photocathode 3a and the electron multiplier 9 3 and an anode 12 for transmitting an output signal for each channel based on the electrons multiplied by each channel of the electron multiplier 9. Here, the electron multiplier 9 is a stacked channel dynode, and a plurality of dynodes 8 are arranged in the first stage (D) from the photocathode 3 a side to the anode 12 side. yl) to the final stage (D y Until 10), the dynodes 8 of each stage define a plurality of channels A, and multiply multiply the electrons emitted from the photocathode 3a for each corresponding channel until the order is reached. The anode 12 includes a plurality of anode pieces 21 facing the final stage dynode 8 and corresponding to a plurality of channels A on a one-to-one basis. An output signal for each channel is transmitted based on the electrons multiplied by the number of channels A in multiple stages.

Here, the shield electrode 15 provided with the plurality of conductive partition members 25 is located between two adjacent anode pieces 21 corresponding to each conductive partition member 25, and two adjacent anode pieces 21 are provided. It is set up to partition the channel. Here, the conductive partition member 25 is formed such that the adjacent node pieces 21 cannot be seen through each other, and the channel pieces A of the last dynode 8 are adjacent to the corresponding anode pieces 2 1. 1 has a shape and size that cannot be seen through. For this reason, the conductive partition member 25 shields the adjacent anode pieces 21 from each other, and the anode piece 2 adjacent to the corresponding anode piece 21 from each channel of the final stage dynode 8. 1 is shielded. An intermediate potential between the final stage dynode potential and the anode potential is applied to the conductive partition member 25. Therefore, electrons emitted from each channel A of the final dynode 8 are prevented from entering the adjacent anode piece 21 next to the corresponding anode piece 21 and the corresponding anode piece is prevented. It is possible to appropriately guide only to 2 1 and suppress emission of electrons from the corresponding anode piece 21 to the adjacent anode piece 21. Therefore, crosstalk in the anode 12 can be prevented, and the resolution of each channel can be increased.

Moreover, an oxide film is formed on the surface of each focusing piece 23 of the first focusing electrode 13. Since it is formed, reflection of light at each converging piece 23 is prevented, and unnecessary electrons due to reflected light are not emitted from the photocathode 3a. Further, since an oxide film is also formed on the surface of each secondary electron emission piece 24 of the first and second dynodes 8, the first and second stages The reflection of the light at the dynode 8 is prevented so that unnecessary electrons due to the reflected light are not emitted from the photocathode 3a. Further, by increasing the length of each of the converging pieces 23 in the tube axis direction, even if light is slightly reflected by the first and second stage die nodes 8, the reflected light To return to the channel next to the photocathode 3a and prevent unnecessary electrons from being emitted from the photocathode 3a. Further, a light absorbing glass partition 26 is provided in the light receiving surface plate 3 to prevent light crosstalk between channels A in the light receiving surface plate 3. In addition, by arranging the condenser lenses 32 on the outer surface 29 of the light-receiving surface plate 3 in correspondence with each channel A, light of each channel A is surely collected. As described above, the partitioning part 26 is formed on the light receiving surface 3, each focusing piece 23 of the first focusing electrode 13 is elongated in the tube axis direction, and each focusing piece 13 of the first focusing electrode 13 is elongated. An oxide film is formed on each of the secondary electron emitting pieces 24 of the piece 23 and the first and second stage dynodes 8 and a condensing lens 32 is provided to suppress crosstalk of light. since the suppress reliably cross-talk between the channels a, Note _c thereby improving the resolution of each channel, in the above description, a plurality of channel a are arranged in the form a one-dimensional array in the electronic增倍9 Was. For this reason, also in the anode 12, as shown in FIGS. 5 (A) and 5 (B), a plurality of rod-shaped anode pieces 21 were arranged one-dimensionally in the lower part.

However, in the electron multiplier 9, a plurality of channels A may be arranged in a two-dimensional matrix. In other words, each stage dyno In Example 8, the plurality of secondary electron multipliers 24 may be arranged in a matrix in a two-dimensional direction including both a direction parallel to the X axis and a direction parallel to the Y axis.

In such a case, in the anode 12, instead of the one-dimensional linear arrangement structure described with reference to FIGS. 5 (A) and 5 (B), for example, FIG. 7 (A) and FIG. 7 (B) A two-dimensional arrangement structure as shown in the figure may be used. More specifically, a plurality of substantially square plate-shaped anode pieces 21 are formed on a ceramic substrate 20 in a matrix in a two-dimensional direction including both a direction parallel to the X axis and a direction parallel to the Y axis. Just arrange them. Also in the shield electrode 15, a plurality of conductive partition members 25 may be arranged in a two-dimensional mesh (lattice) shape and connected to the frame plate 22. As a result, a substantially square opening 15a is formed between the adjacent conductive partition members 25. The shielding electrode 15 having such a structure is arranged on the ceramic substrate 20 such that each of the anode pieces 21 is located in the corresponding opening 15a.

In this two-dimensional arrangement, as shown in FIG. 7 (B), the height z 1 of each conductive partition member 25 in the tube axis direction is the height _Z 2 of the anode piece 21. The height may be increased so that the adjacent anode pieces 21 cannot be seen through each other, and the adjacent anode pieces 21 may be shielded from each other. Even if secondary electrons are emitted from the anode piece 21, it is possible to prevent the secondary electrons from being incident on the adjacent anode piece 21. In addition, the height z1 of each conductive partition member 25 in the tube axis direction is increased so that the upper end thereof is close to the lower end of the corresponding secondary electron emission piece 24 of the final dynode 8, so that the final stage It suffices that the channel piece 21 adjacent to the corresponding node piece 21 from each channel A of the dynode 8 cannot be seen through. Since each channel A of the final dynode 8 can shield the adjacent node 21 of the corresponding node 21, the electric power emitted from each channel A of the final dynode 8 can be shielded. It is possible to prevent a child from entering the adjacent node piece 21.

Further, in FIG. 7 (B), both the anode piece 21 and the conductive partition member 25 have a rectangular cross section, but may have any other cross section.

(Second embodiment)

A photomultiplier tube according to a second embodiment of the present invention and a method of using the same will be described with reference to FIG.

As shown in FIG. 8, the photomultiplier tube 1 according to the present embodiment has a second focusing electrode 17 provided between the last stage (the tenth stage) dynode 8 and the anode 12. Except for this point, it is the same as the photomultiplier tube 1 of the first embodiment described with reference to FIG. 4, FIG. 5 (A), and FIG. 5 (B).

In the present embodiment, the second focusing electrode 17 has a plurality of linear focusing pieces 27 arranged in parallel with each other. A slit-like opening 17a is formed between adjacent converging pieces 27. Therefore, the plurality of openings 17a are linearly arranged in one direction (a direction parallel to the X axis). The plurality of openings 17 a correspond one-to-one with the plurality of electron multiplication paths L (the plurality of channels A) of the electron multiplier 9. Each opening 17 a is used to converge the electrons emitted from the corresponding channel A of the final dynode 8 (Dy 10) of the electron multiplier 9 and to guide the electrons to the corresponding anode piece 21. It is.

Here, a predetermined potential required to form an electron lens suitable for guiding electrons from each channel A of the final stage dynode 8 to the corresponding anode piece 21 is applied to the second focusing electrode 17. Applied. For example, the same potential as that of the final-stage dynode 8 is applied to the second focusing electrode 17. Specifically, as in the example described above, when 180 V is applied to the photocathode 3a and the anode potential is set to 0 V, the final stage (stage 10) dynode 8 and the Income of 2 It suffices to apply −72.7 V to the bundle electrode 1 等しい and to apply −36.4 V to the shield electrode 15.

According to such a configuration, the electrons emitted from any channel Α (any electron multiplication path L) of the final stage dynode 8 of the electron multiplication unit 9 are transmitted to the corresponding aperture of the second focusing electrode 17. It passes through section 17a, where it is converged and reliably guided by the corresponding anode piece 21.

According to the present embodiment, electrons emitted from any channel A of final stage dynode 8 can be more reliably guided to corresponding anode piece 21 by second focusing electrode 17. . Therefore, it is possible to more reliably prevent electrons from arriving at the adjacent anode piece 21 by mistake. In addition, the shield electrode 15 to which the intermediate potential between the final dynode 8 and the anode 12 is applied can reliably suppress the secondary electrons to the anode node 21.

Note that, also in the present embodiment, when the plurality of channels A are arranged in a two-dimensional matrix in the electron multiplier 9, as in the case of the first embodiment, the anode 12 Instead of the one-dimensional linear structure shown in FIGS. 5 (A) and 5 (B), a two-dimensional arrangement structure shown in FIGS. 7 (A) and 7 (B) may be used.

The photomultiplier tube and the method of using the same according to the present invention are not limited to the above-described embodiments, and various modifications and improvements can be made within the scope described in the claims.

For example, in the above embodiment, the shielding electrode 15 is formed by integrally forming the plurality of conductive partition members 25 with the frame plate 22. Then, the shielding electrode 15 was disposed on the ceramic substrate 20. However, a plurality of conductive partition members 25 are individually formed, and the ceramic partition member 25 is positioned between two adjacent anode pieces 21 so that the ceramic partition member 25 is located between two adjacent anode pieces 21. It may be arranged on the substrate 20.

In the above embodiment, anode piece 21 was arranged on ceramic substrate 20. However, such a configuration is not necessary. For example, the anode piece 21 may be formed by vapor deposition on an insulating substrate.

The shape and arrangement of each anode piece 21 and each conductive partition member 25 are not limited to those in the above-described embodiment, and each conductive partition member 25 may be configured to receive electrons from each channel of the final stage die node 8. Function to block the anode node 21 of the adjacent channel from entering the adjacent anode node 21 and to block the electrons emitted from the anode node 21 from entering the adjacent anode node 21. As long as it has.

In the above embodiment, various configurations for preventing crosstalk due to light transmitted through the photocathode 3a have been employed. However, such a configuration need not be adopted. Therefore, it is not necessary to perform the light non-reflection processing on the converging piece 23 of the first converging electrode 13 and the first-stage / second-stage dynode 8. Further, the focusing piece 23 of the first focusing electrode 13 need not be long in the tube axis direction. The light receiving surface plate 3 does not need to be formed with the partition part 26. The light collecting member 30 may not be formed on the light receiving surface plate 3. Industrial applicability

INDUSTRIAL APPLICABILITY The photomultiplier according to the present invention and a method for using the same are widely used in applications that detect weak light, such as a laser scanning microscope and a DNA sequencer used in the detection field and the like.

Claims

The scope of the claims

1. A photocathode that emits electrons when light enters,

It has a plurality of dynodes, and the plurality of dynodes are arranged in this order from the side of the photocathode from the first stage to the last stage, and the dynodes of each stage are arranged in a plurality of channels. A stacked channel dynode section for multiplying electrons emitted from the photocathode for each corresponding channel in multiple stages;

A plurality of anode electrodes are provided facing the final dynode and in a one-to-one correspondence with the plurality of channels. A node for transmitting an output signal for each channel based on the multiplied electrons;

A plurality of conductive partition members are provided so as to face the final dynode, and each conductive partition member is provided between two corresponding anode electrodes adjacent to each other. A shielding electrode to which a potential between a predetermined anode potential applied to each anode electrode and a predetermined final dynode potential applied to the final stage dynode is applied;

A photomultiplier tube comprising:

2. The photocathode and the first to final dynodes are so arranged that the potential is sequentially increased from the photocathode to the anode via the first to final dynodes. A voltage is applied to the anode and a potential higher than the final dynode potential and lower than the anode potential is applied to each of the conductive partition members, and the potential is released from an arbitrary channel of the final dynode. 2. The method according to claim 1, wherein electrons are made incident on a corresponding anode electrode, and secondary electrons are suppressed from being emitted from the anode electrode in response to the electrons being incident on the corresponding anode electrode. Photomultiplier tube.

3. The difference between the potential applied to the conductive partitioning member and the potential of the final dynode causes the electrons emitted from each channel of the final dynode to properly enter the corresponding anode electrode. The difference between the potential applied to the conductive partition member and the anode potential is such that electrons emitted from each channel of the final stage dynode are located on both sides of the corresponding anode electrode. Having a size to prevent secondary electrons generated at the anode electrode from entering the adjacent anode electrode of the corresponding anode electrode. The photomultiplier tube according to claim 2, wherein the photomultiplier tube is used.

4. The difference between the potential applied to the conductive partition member and the anode potential 1 The difference between the anode potential and the final dynode potential is in the range of about 5% to about 70%. 3. The photomultiplier tube according to claim 2, wherein

5. The difference between the potential applied to the conductive partition member and the anode potential is about 50% of the difference between the anode potential and the last-stage dynode potential. Photomultiplier tube.

6. The conductive partitioning member according to claim 1, wherein each of the conductive partition members has a size that shields between the adjacent anode electrodes and does not allow electrons emitted from the anode electrodes to be input to the adjacent anode electrodes. Photomultiplier tube.

7. The height of the conductive partition member extending toward the final stage node is higher than the height of each of the anode electrodes extending toward the final stage node, and from each of the anode electrodes. 7. The photomultiplier tube according to claim 6, wherein an adjacent anode electrode cannot be seen through.

8. Each of the conductive partitioning members is a respective one of the channels of the last-stage dynode. And shields the anode and the anode electrode adjacent to the corresponding anode electrode, and emits electrons emitted from each channel of the final stage anode to the anode electrode adjacent to the corresponding anode electrode. The photomultiplier tube according to claim 1, wherein the photomultiplier tube has a size that does not allow input.

9. The dynode of each stage has a plurality of secondary electron emitting pieces, and the height of the conductive partition member extending toward the final stage dynode is such that the upper end of the conductive partition member has the final end. 9. The anode of a next channel which has a size close to the lower end of the corresponding secondary electron emitting piece of the stage dynode, and wherein the anode electrode of an adjacent channel cannot be seen from each channel of the final stage dynode. Photomultiplier tube.

10. The anode further includes an anode substrate formed of a ceramic substrate, wherein the plurality of anode electrodes are provided on the anode substrate in one-to-one correspondence with the plurality of channels, and the shielding electrode is provided. Is further provided with a frame-shaped member, wherein the plurality of conductive partition members are formed integrally with the frame-shaped member, and the shielding electrode comprises two adjacent ones corresponding to the respective conductive partition members. 2. The photomultiplier tube according to claim 1, wherein the photomultiplier tube is arranged on the anode substrate so as to be located between the anode electrodes.

1 1. The plurality of channels are linearly arranged in one direction, and the plurality of anode electrodes are one-dimensionally arranged substantially parallel to the direction. 2. The photomultiplier tube according to claim 1, wherein the photomultiplier tube is provided between the two adjacent anode electrodes in the original direction.

12. The plurality of channels are arranged in a two-dimensional matrix, the plurality of anode electrodes are arranged in a two-dimensional matrix, and each of the conductive partition members is arranged in the two-dimensional direction. In each of the directions described above, it is provided between two adjacent anode electrodes. The photomultiplier tube according to claim 1, wherein

13. A plurality of converging pieces provided between the anode and the last-stage dynode, and two converging pieces adjacent to each other define one opening therebetween, thereby forming a plurality of opening parts. By converging the electrons emitted from each channel of the last-stage die node at the corresponding opening and guiding the electrons to the corresponding anode electrode, the electrons emitted from the last-stage die node are defined. 2. The photomultiplier tube according to claim 1, further comprising: a focusing electrode for focusing the light for each channel.

14. The photomultiplier according to claim 13, wherein a potential substantially the same as the final dynode potential is applied to the focusing electrode.

15. Provided between the photocathode and the stacked channel dynode portion and having a plurality of different converging pieces, each two adjacent converging pieces defining one opening therebetween. Thus, a plurality of openings are defined, and electrons emitted from an arbitrary position on the photocathode are converged at the corresponding opening and guided to the corresponding channel of the stacked channel die node. 14. The photomultiplier according to claim 13, further comprising another focusing electrode for focusing electrons emitted from an arbitrary position on the photocathode for each channel. .

16. The photomultiplier according to claim 15, wherein substantially the same potential as that of the photocathode is applied to the other focusing electrode.

17. A light-receiving surface plate, and a wall for forming a vacuum region together with the light-receiving surface plate, wherein the photoelectric surface is formed on the inner surface of the light-receiving surface plate inside the vacuum region, A dynode section, the anode, the shielding electrode, and the focusing electrode; A light-absorbing glass partition portion is provided in the light-receiving surface plate corresponding to each of the channels, and a light-collecting device is provided on the outer surface of the light-receiving surface plate in correspondence with each of the channels. The surface of each of the converging pieces is subjected to a light non-reflection treatment, and the die node of each stage has a plurality of secondary electron emitting pieces that define the plurality of channels; An anti-reflection treatment is performed on the surface of each of the secondary electron emission pieces defining the respective channels of the dynodes located at the first and second stages from the photocathode side of the dynode. Has been given,

The length of the focusing surface defining the respective channels of the different focusing electrode extending toward the photoelectric surface and the stacked channel dynode portion is the photoelectric surface side of the plurality of dynodes. The light reflected on the surface of each of the secondary electron emission pieces defining the respective channels of the dynodes located at the first and second stages returns to the next channel position in the photocathode. 16. The photomultiplier tube according to claim 15, having a size to prevent it.

1 8. A photocathode that emits electrons when light enters,

It has a plurality of dynodes, and the plurality of dynodes are arranged in this order from the side of the photocathode to the first stage to the last stage, and each dynode defines a plurality of channels. A stacked channel dynode unit for multiplying the electrons emitted from the photocathode for each corresponding channel in multiple stages;

A plurality of anode electrodes are provided so as to face the final stage dynode and correspond to the plurality of channels on a one-to-one basis, and are multi-stage multiplied by the plurality of channels of the stacked channel dynode part. An anode that sends an output signal for each channel based on the electrons A plurality of conductive partitioning members facing the final dynode, a shielding electrode provided between two adjacent anode electrodes corresponding to each conductive partitioning member,

In a photomultiplier tube with

Applying a predetermined anode potential to each anode electrode,

A photoelectron, wherein a predetermined final dynode potential is applied to the final dynode, and a potential between the anode potential and the final dynode potential is applied to each conductive partition member. How to use the multiplier.

19. Further, the photocathode and the first to final stages are so arranged that a potential is sequentially increased from the photocathode to the anode via the first to final stage dynodes. Applying a voltage to the eye dynode and the anode,

The potential applied to each of the conductive partition members is higher than the final-stage dynode potential and lower than the anode potential. Electrons emitted from an arbitrary channel of the final-stage dynode are converted into a corresponding anode. 19. The photoelectron enhancement device according to claim 18, wherein the photoelectron is made incident on the anode electrode, and secondary electrons are suppressed from being emitted from the anode electrode in response to the electron incidence on the corresponding anode electrode. How to use the multiplier.

20. The difference between the potential applied to the conductive partition member and the potential of the last-stage dynode has a magnitude enough to cause electrons emitted from each channel of the last-stage dynode to appropriately enter the corresponding anode electrode. The difference between the potential applied to the conductive partition member and the anode potential is such that electrons emitted from each channel of the final stage node are located on both sides of the corresponding anode electrode. Having a size to prevent the secondary electrons generated at the anode electrode from being incident on the anode electrode adjacent to the corresponding anode electrode; Claims characterized by Item 19. Use of the photomultiplier tube according to item 19.

21. The difference between the potential applied to the conductive partition member and the anode potential is within a range of about 5% or more and about 70% or less of the difference between the anode potential and the final-stage node potential. 10. The method for using a photomultiplier tube according to claim 19, wherein:

22. The difference between the potential applied to the conductive partition member and the anode potential is about 50% of the difference between the anode potential and the final dynode potential. Use of the photomultiplier described.

23. The photomultiplier tube has a plurality of converging pieces provided between the anode and the last dynode, and two adjacent converging pieces have one opening therebetween. By defining a plurality of openings, the electrons emitted from each channel of the final dynode are converged at the corresponding openings and guided to the corresponding anode electrodes. A focusing electrode for focusing the electrons emitted from the final-stage die node for each channel;

19. The method according to claim 18, further comprising: applying a potential substantially equal to the final dynode potential to the focusing electrode.