JP5284635B2 - Electron multiplier - Google Patents

Description

  The present invention relates to an electron multiplier that multiplies an incident electron current by an electron multiplier made of dynodes stacked in multiple stages.

2. Description of the Related Art Conventionally, as an electron multiplying device having an electron multiplying portion having a structure in which dynodes are stacked, a conductive layer and a line-shaped separator in which holes for forming a channel are formed in order to arrange a plurality of dynodes separately from each other An apparatus in which layers are alternately arranged is known (see Patent Document 1 below). Further, it has been clarified that when a resistive material is used for the separator in such a device, an external resistor or an external device for setting the potential of the intermediate electrode can be omitted.
JP-A-48-74167

  However, in the above-described electron multiplier, when the separator is a resistive separator, the separator is exposed in the internal space of the electron multiplier, so that the multiplier electrons are incident on the separator. On the other hand, damage may be caused and the resistance value of the separator may change. As a result, the voltage applied to each dynode may change, changing the electron multiplication efficiency and detection efficiency in some cases. For example, when the resistance value of the separator is remarkably increased, the amount of charge supplied to each electrode is reduced and the electron multiplication efficiency is reduced. When the resistance value of the separator is remarkably reduced, the potential difference between the dynodes is reduced. The electron multiplication efficiency becomes lower. In other words, for the same size input, the obtained output changes, and the detection sensitivity may become unstable.

  Accordingly, the present invention has been made in view of such problems, and by reducing the power feeding section in the electron multiplier section, the electron multiplier capable of stabilizing the detection sensitivity while reducing the size of the electron multiplier section. The purpose is to provide a double tube.

In order to solve the above problems, an electron multiplier of the present invention is an electron multiplier having an electron multiplier section in which dynodes, which are plate electrodes having electron multiplier holes for multiplying incident electrons, are stacked in a plurality of stages. Between the adjacent two-stage dynodes, spacers, which are insulating frame-like members having conductive paths that electrically connect the two-stage dynodes, are arranged between the adjacent two-stage dynodes. A part of the path is formed by a resistor covered with an insulator.

  According to such an electron multiplier, two adjacent dynodes in the electron multiplier section composed of a plurality of dynodes are electrically connected via a resistor by a conductive path of a spacer disposed between them. As a result, it is possible to generate a desired potential difference between adjacent dynodes by applying a voltage across the dynodes of a plurality of stages connected in series. can do. In addition, since the resistor is covered with an insulator and not exposed to the space in the tube, a change in the resistance value of the resistor due to the influence of the multiplying electrons can be suppressed, and the electron multiplication efficiency can be reduced. Stabilization is possible. Thereby, it is possible to stabilize the detection sensitivity while reducing the size of the electron multiplier.

  The conductive path has a first connection portion for electrically connecting with one of the two-stage dynodes, a second connection portion for electrically connecting with the other of the two-stage dynodes, It is preferable that the wiring part covered with the insulator which electrically connects a connection part and a 2nd connection part via a resistor is included. In this case, the conductive path is connected to each of the adjacent two-stage dynodes at the connection portion, and these two-stage dynodes are connected via the resistor by the wiring portion covered with the insulator. The generation of noise due to the incidence of electrons on the part can be suppressed, and the detection sensitivity can be stabilized.

  It is also preferable that there are a plurality of first connection portions and second connection portions. By providing a plurality of connection portions, it is surely electrically connected to two adjacent dynodes, so that a stable potential can be supplied and detection sensitivity can be further stabilized.

  The wiring unit includes a first wiring unit that couples the plurality of first connection units, a second wiring unit that couples the plurality of second connection units, a first wiring unit, and a second wiring unit. It is also preferable that the resistor forms a part of the intermediate wiring portion. With such a configuration, a plurality of first connection portions and second connection portions for electrically connecting the spacer and the adjacent two-stage dynodes are connected by the first and second wiring portions, Since the 1st and 2nd wiring part is connected by the intermediate | middle wiring part containing a resistor, the connection structure of a 1st connection part and a 2nd connection part, and a resistor is simplified.

  It is also preferable that the spacer has a frame shape surrounding the region where the electron multiplying holes of the dynode are formed. In this way, the detection sensitivity can be stabilized by stably maintaining the distance between the dynodes.

  The first connection portion and the second connection portion are formed with depressions or protrusions, and each of the two-stage dynodes is formed with at least one protrusion or depression, and one dynode of the two-stage dynodes. Are fitted into the depressions or protrusions of the first connection part, so that one dynode and the wiring part are electrically connected, and the protrusions or depressions of the other dynode of the two-stage dynodes are It is also preferable that the other dynode and the wiring portion are electrically connected by being fitted in the recess or protrusion of the second connection portion. In this way, since the protrusions or depressions formed in the two adjacent dynodes are fitted into the connecting portion provided in one spacer, the positioning of the dynodes is facilitated, and the detection sensitivity is further stabilized. It becomes possible.

  The spacer is provided on one dynode side of the two-stage dynodes, and includes a first insulating member including a first connection portion for electrically connecting to the one dynode, and the other of the two-stage dynodes. A second insulating member provided on the dynode side and including a second connecting portion for electrically connecting to the other dynode, and a third insulating member held between the first and second insulating members A first wiring portion provided between the first insulating member and the third insulating member and electrically connected to the first connecting portion, a second insulating member, and a third insulating member Between the second wiring part electrically connected to the second connecting part and the third insulating member, and connecting the first wiring part and the second wiring part. It is preferable that a part of the intermediate wiring part is formed by a resistor. . In this case, since the resistor is surely surrounded by the insulating member, the detection sensitivity can be stabilized.

  Moreover, it is also preferable that the first wiring portion, the second wiring portion, and the intermediate wiring portion are formed on the third insulating member. By adopting such a configuration, it is easy to form a conductive path in the spacer, and the manufacturing efficiency is improved.

  ADVANTAGE OF THE INVENTION According to this invention, the electron multiplier which can stabilize a detection sensitivity can be provided, reducing an electron multiplier part by reducing the electric power feeding part in an electron multiplier part.

  Hereinafter, preferred embodiments of an electron multiplier according to the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is an end view along a tube axis direction of a photomultiplier tube 1 which is an electron multiplier tube according to a preferred embodiment of the present invention. The photomultiplier tube 1 sandwiches a circular light-receiving surface plate 2 that receives incident light, a cylindrical metal side tube 3 attached to the outer edge of the light-receiving surface plate 2, and the metal side tube 3. The vacuum vessel 5 is constituted by a circular stem 4 disposed so as to face the light receiving face plate 2, and the focusing electrode 6, the electron multiplier 7, and the anode 8 arranged in the vacuum vessel 5. ing. The size of the photomultiplier tube 1 is not limited to a specific size. For example, the length of the vacuum vessel 5 in the tube axis Z direction is 12 mm, and the width in the direction perpendicular to the tube axis Z is 15 mm.

  A photocathode 2a is provided on the inner surface of the light-receiving face plate 2. Between the photocathode 2a and the electron multiplying unit 7, the photocathode 2a is substantially perpendicular to the tube axis Z direction (X-axis direction in FIG. 1). Linear focusing electrodes 6 are provided so as to be arranged at equal intervals. The converging electrode 6 causes the photoelectrons emitted from the photocathode 2a into the vacuum vessel 5 as light enters the light-receiving face plate 2 from the outside to enter the electron multiplier 7 by converging the trajectory.

  The electron multiplying unit 7 includes a plurality of dynodes 10 having a plurality of electron multiplying holes 9 stacked in the tube axis Z direction. A substantially rectangular anode 8 is disposed facing the electron multiplying hole 9 of the dynode 10. The stem 4 is connected to an external bleeder circuit, and is provided with a stem pin 11 through which a predetermined voltage is applied to the photocathode 2a, the focusing electrode 6, the electron multiplier 7 and the anode 8. .

  The number of stages of the dynodes 10 and the voltage applied to the stem pin 11 can be set variously. For example, the dynodes 10 are stacked in eight stages, and the voltages applied to the photocathode 2a, the focusing electrode 6, each dynode 10 and the anode 8 are stacked. Are set to -900 V, -900 V, -800 to -100 V (100 V interval), and 0 V (ground potential), respectively, so as to increase from the photocathode 2 a toward the anode 8. As a result, the incident electron current is multiplied from upstream to downstream in the electron multiplication path, specifically, from the foremost dynode 10 toward the last dynode 10, and externally detected as a detection signal at the anode 8. To be taken out.

  Each dynode 10 has slit-like electrons parallel to each other along a direction perpendicular to the tube axis Z direction (Y-axis direction in FIG. 1) on a substantially rectangular plate electrode made of stainless steel or aluminum. A plurality of multiplication holes 9 are formed. The plurality of dynodes 10 are stacked at predetermined intervals with each other through a frame-like spacer 12a. For example, the dynode 10 has electron multiplying holes 9 formed at intervals of 1 mm on a 9 mm square, 0.1 mm thick stainless steel flat plate, and is laminated at a pitch of 0.8 mm. At this time, the two adjacent dynodes 10 are stacked via the spacers 12a, so that they are mutually in the direction along the plane perpendicular to the tube axis Z (XY plane) and the direction along the tube axis Z. Aligned. Thereby, the electron multiplying hole 9 formed in the dynode 10 has an opening 9a on the front stage side (focusing electrode 6 side) thereof and an opening 9b on the rear stage side (anode 8 side) of the electron multiplying hole 9 of the preceding dynode 10. Zigzag-shaped electron multiplying channels are formed in parallel along the tube axis Z direction.

  The foremost dynode 10 and the focusing electrode 6 are stacked with each other via the spacers 12b, so that they are aligned with each other in the direction along the XY plane and the direction along the Z axis. Similarly, the last dynode 10 and the anode 8 are stacked with the spacer 13 interposed therebetween, so that they are aligned with each other in the direction along the XY plane and the direction along the Z axis. As will be described later, the spacers 12a and 12b have a structure in which a conductive path is formed inside a three-layered frame-shaped insulator made of an insulating material such as ceramic, while the spacer 13 has one layer. The entire structure is a frame-like insulating member made of an insulating material such as ceramic.

  Next, with reference to FIG. 2 and FIG. 3, the laminated structure of the electron multiplier section 7 will be described in detail. 2 is a plan view of the electron multiplier section 7 including the focusing electrode 6 of FIG. 1, and FIG. 3 is an exploded perspective view showing a part of the focusing electrode 6 and the electron multiplier section 7 of FIG.

  Two substantially circular protrusions 14a and 14b are formed on two diagonal corners of the four corners of the edge 6a of the surface 6a on the light receiving face plate 2 side of the focusing electrode 6, and on the other diagonal of the surface 6a. Two substantially circular depressions 15c and 15d are formed at the two corners of the edge located at. Further, at the positions on the opposite side of the projections 14a and 14b on the surface 6b of the focusing electrode 6 on the electron multiplication unit 7 side, substantially circular shapes having substantially the same size as the projections 14a and 14b, respectively. Recesses 15a and 15b are formed, and substantially circular projections 14c having substantially the same size as the recesses 15c and 15d, respectively, at positions opposite to the recesses 15c and 15d on the surface 6b. 14d is formed.

  Similarly, two substantially circular projections 16a and 16b are formed at two corners on the diagonal line among the four corners of the edge portion of the front surface 10a of the dynode 10 on another diagonal line of the surface 10a. Two substantially circular depressions 17c and 17d are formed at the two corners of the edge located at. Further, at the position on the opposite side to the protrusions 16a and 16b on the surface 10b on the rear stage side of the same dynode 10, the substantially circular recess 17a having substantially the same size as the protrusions 16a and 16b, respectively. 17b are formed, and substantially circular projections 16c and 16d having substantially the same size as the depressions 17c and 17d are formed at positions opposite to the depressions 17c and 17d on the surface 10b, respectively. Has been.

  The spacers 12 a and 12 b are frame-shaped members having edge shapes that are substantially the same as the edge shapes of the focusing electrode 6 and the dynode 10. When the spacer 12a and the spacer 12b are disposed between the two dynodes 10 and between the focusing electrode 6 and the frontmost dynode 10, the electron multiplying hole 9 of the electron multiplying portion 7 is formed. In order not to cover the region A (see FIG. 1), the central portion is cut out in a rectangular shape with a size sufficient to surround the region A. In addition, the spacer 12b has a circular hole (dent) 18 formed at a corner facing the protrusions 14c, 14d, 16a, and 16b when the spacer 12b is disposed between the focusing electrode 6 and the dynode 10. ing. Similarly, the spacer 12a is formed with a circular hole (dent) 19 at a corner facing the protrusions 16a, 16b, 16c, 16d when the spacer 12a is disposed between the two dynodes 10. These holes 18 and 19 are formed on both surfaces of the corners of the spacers 12b and 12a, respectively.

  When the two dynodes 10 having the above-described shape are stacked via the spacer 12a, the protrusions 16c and 16d of the front dynode 10 are fitted into the two holes 19 on the diagonal line of the spacer 12a, and the rear stage The protrusions 16a and 16b of the dynodes 10 are stacked on each other by being fitted into two holes 19 on another diagonal line of the spacer 12a. Further, when the focusing electrode 6 and the foremost dynode 10 are stacked via the spacer 12b, the protrusions 16a and 16b of the dynode 10 are fitted into the two holes 18 on the diagonal line of the spacer 12b, The protrusions 14c and 14d of the focusing electrode 6 are stacked on each other by being fitted into the two holes 18 on another diagonal line of the spacer 12b. As a result, the focusing electrode 6 and the plurality of stages of dynodes 10 are aligned in the direction perpendicular to the tube axis Z and the direction along the tube axis Z. In this way, the focusing electrode 6 to the final stage dynode 10 are stacked via the spacers 12a and 12b.

  Next, a detailed configuration of the spacer 12a (spacer 12b) will be described. 4 is a plan view of the spacer 12a, FIG. 5 is a cross-sectional view taken along line VV of the spacer 12a in FIG. 4, FIG. 6 is a cross-sectional view taken along line VI-VI of the spacer 12a in FIG. FIG. 8 is a perspective view of the spacer 12a of FIG. 4 as viewed from above, and FIG. 8 is a perspective view of the spacer 12a of FIG. 4 as viewed from below. The spacer 12b differs from the spacer 12a in its thickness, but the basic configuration is the same, and thus the description thereof is omitted.

  The spacer 12a is formed by superimposing three rectangular frame-shaped insulating members 21A, 21B, and 21C and integrating them with each other. The insulating member 21A is disposed on the dynode 10 side of the previous stage, and the insulating member 21C. Is disposed on the dynode 10 side on the rear stage side, and the insulating member 21B is held between the two insulating members 21A and 21C. The insulating member 21B includes a wiring portion including a first wiring portion 22, a second wiring portion 23, and an intermediate wiring portion 24 on both surfaces and inside of the through hole, and electrically connects the two dynodes 10 sandwiching the spacer 12a. A conductive path 25 is formed to connect to the. Further, the conductive path 25 is formed at the four corners of the insulating member 21A, and has four holes 19 (first connection portions) for electrically connecting the dynode 10 and the first wiring portion 22 in the previous stage, and insulation. Four holes 19 (second connection portions) are provided at the four corners of the member 21C and electrically connected to the second dynode 10 and the second wiring portion 23, respectively.

  The first wiring portion 22 extends from the middle portion of one side to the other corner portion 26d via the three corner portions 26a, 26b, and 26c on the surface 26 on the dynode 10 side of the preceding stage of the insulating member 21B. The second wiring portion 23 is formed along the outer edge of the surface 26 without protruding from the surface 26 (FIG. 7). The second wiring portion 23 is formed on the surface 27 on the dynode 10 side after the insulating member 21B from the middle portion of one side. It is formed along the outer edge of the surface 27 without protruding from the surface 27 until it reaches the other corner portion 27d via the three corner portions 27a, 27b, 27c (FIG. 8).

  In addition, a resistor 28 formed without protruding from the surface 27 by screen printing at the end portion between the corner portion 27a and the corner portion 27d of the second wiring portion 23, and both surfaces 26, 27 of the insulating member 21B. An intermediate wiring portion 24 including an interlayer connection through hole 29 formed therethrough is connected (FIGS. 6 and 8). One end of the resistor 28 is connected to the end of the second wiring portion 23, the other end of the resistor 28 is connected to the through hole 29 on the surface 27, and the through hole 29 is further connected to the first wiring on the surface 26. It is connected to the end of the part 22 (FIG. 6). That is, the intermediate wiring portion 24 has a function of electrically connecting the first wiring portion 22 and the second wiring portion 23 via the resistor 28.

  The hole portion 19 formed in the insulating member 21A is coated with the conductive material 30 from the inner surface to the surface 26 side of the insulating member 21B, and when the conductive material 30 comes into contact with the first wiring portion 22, The hole 19 and the first wiring part 22 are electrically connected. Similarly, the hole 19 formed in the insulating member 21 </ b> C is coated with the conductive material 30 from the inner surface to the surface 27 side of the insulating member 21 </ b> B, and the conductive material 30 comes into contact with the second wiring portion 23. Thereby, the hole part 19 and the 2nd wiring part 23 are electrically connected (FIG. 5). Thereby, the 1st wiring part 22 and the 2nd wiring part 23 connect and connect each of the four hole parts 19 of the insulating member 21A, and the four hole parts 19 of the insulating member 21C, so that the insulating member 21A can be connected. The hole 19 and the hole 19 of the insulating member 21 </ b> C are connected via a resistor 28.

  With reference to FIG. 9, the feeding direction between dynodes when the spacer 12a having the above-described configuration is arranged between two dynodes will be described. As shown by the arrow B in the figure, the projections 16c and 16d of the preceding dynode 10 and the two holes 19 of the spacer 12a are connected, so that two ridges from the preceding dynode 10 to the two corners of the spacer 12a are connected. Charge flows in. The electric charge flowing into the two corners reaches the four holes 19 on the dynode 10 side in the subsequent stage via the first wiring part 22, the intermediate wiring part 24 including the resistor 28 and the second wiring part 23. . Then, the electric charge that has reached the hole 19 flows through the protrusions 16 a and 16 b fitted in the hole 19 and flows into the dynode 10 on the rear stage side. In this way, it can be seen that charges are supplied between the two adjacent dynodes 10 via the resistor 28. At this time, in the spacer 12a sandwiched between the two dynodes 10, the first wiring part 22, the intermediate wiring part 24 including the resistor 28, and the second wiring part 23 are covered with the insulating members 21A, 21B, and 21C. That is, it is not exposed to the internal space of the vacuum vessel 5. Here, one dynode 10 and the conductive path 25 are connected at two points, but the conductive material 30 formed in the hole 19 is in contact with the periphery of the recesses 17a, 17b, 17c, and 17d of the dynode 10. By doing so, it is possible to connect at four points.

  Note that the resistance value of the resistor 28 formed on the surface 27 of the insulating member 21B may be adjusted by laser trimming. At this time, since adjustment is preferably performed when the insulating members 21A, 21B, and 21C are overlapped to form the spacer 12a, an opening is provided in a portion of the insulating member 21C that faces the resistor 28, and the opening is formed through the opening. After adjusting the resistance value, it is preferable to fill or coat the opening of the insulating member 21C with an insulating material such as a glass material in order to more reliably protect the resistor 28 from the multiplying electrons.

  According to the photomultiplier tube 1 described above, two adjacent dynodes 10 among the plurality of dynodes 10 constituting the electron multiplier section 7 are connected by the conductive path 25 of the spacer 12a disposed between them. As a result of being electrically connected via the resistor 28, a desired potential difference can be generated between adjacent dynodes 10 by applying a voltage across the dynodes 10 connected in series. In addition, the number of connection terminals as a power feeding unit for applying a voltage to the dynode 10 can be reduced, and the electron multiplying unit 7 can be reduced in size. For example, as shown in FIG. 10 which is an assembly drawing of the focusing electrode 6, the electron multiplying unit 7 composed of a plurality of stages of dynodes 10, and the anode 8, a connection pin 31A that is one of the stem pins 11 (see FIG. 1), The connection pin 31B and the connection pin 31C are connected to the convergence electrode 6, the last dynode 10 and the anode 8, respectively, and the resistance value of the resistor 28 built in the spacers 12a and 12b is set to about 100 kΩ to several hundred kΩ. . In this case, if a voltage is applied between the connection pin 31A and the connection pin 31B, the resistor 28 functions as a voltage dividing (divided voltage) resistor, whereby a voltage is directly applied from the outside to each dynode 10 other than the last stage. It can be set to a predetermined voltage without application. As a result, the electron multiplier 7 can be reduced in size by reducing the number of connection terminals, and the space for the stem pins 11 in the vacuum vessel 5 and the area occupied by the stem pins 11 with respect to the stem 4 can be greatly reduced. The effective area with respect to the size of the vacuum vessel 5 (the region A (see FIG. 1) where the electron multiplying holes 9 of the electron multiplying portion 7 are formed) can be increased. Of course, an electron tube with a small number of pins can be obtained, and the cost can be reduced. When the convergence electrode 6 is not necessary, a voltage is applied to the connection pin 31A and the connection pin 31B connected to the dynodes 10 at the foremost stage and the last stage.

  Further, since the resistor 28 is covered with the insulating members 21B and 21C and is not exposed to the space in the vacuum vessel 5, it is possible to suppress a change in the resistance value of the resistor 28 due to the influence of the multiplying electrons. This makes it possible to stabilize the electron multiplication efficiency. In the case of the photomultiplier tube 1, when an alkaline substance for forming the photocathode 2 a adheres to the resistor 28, there is a possibility that the resistance value of the resistor 28 changes due to the influence. And the electron multiplication efficiency can be stabilized. Further, since the resistor 28 is formed on the insulating member 21B by screen printing, it can be easily set to a desired resistance value. On the other hand, the interstage distance of the dynode 10 can be easily adjusted by the thickness of the insulating members 21A, 21B, and 21C itself. That is, as compared with the case where the resistance value is generated in the entire spacer, it is possible to select an optimal state for each of them without having a relationship between the interstage distance of the dynode 10 and the resistance value. Thereby, it is possible to stabilize the detection sensitivity while reducing the size of the electron multiplier section 7.

  In addition, the conductive path 25 is connected to and connected to a plurality of connection points (connection portions) of the adjacent two-stage dynodes 10, and these two-stage dynodes 10 are covered with an insulator. Since the second wiring part 23 and the intermediate wiring part 24 are connected to each other via the resistor 28, it is possible to suppress the generation of noise and the peeling of the wiring part due to the incidence of electrons on each wiring part. Further, since each dynode 10 has a plurality of connecting portions, for example, even when warpage or the like occurs in the dynode 10, the contact can be reliably maintained and stable potential supply can be performed. At the same time, a more uniform potential can be set over the entire dynode. Further, the formed spacers 12a and 12b can be used without any front and back, and the manufacturing efficiency of the entire apparatus is improved. Further, since the plurality of connecting portions are connected by the first wiring portion 22 and the second wiring portion 23 and are connected to each other via the resistor 28 by the intermediate wiring portion 24, the resistor 28 is provided for each connecting portion. The connection structure between each connection portion and the resistor 28 can be simplified without providing wiring until the entire wiring portion is shortened, and a more uniform potential can be set over the entire dynode. it can. As a result, the detection sensitivity can be stabilized as a result.

  Furthermore, since the spacers 12a and 12b have a frame-like shape surrounding the region A in which the electron multiplier holes 9 of the dynode 10 are formed, an increase in the contact area with the edge of the dynode 10 increases the distance between the dynodes 10. , The electron multiplication function by the dynodes 10 in a plurality of stages can be maintained, and the detection sensitivity can be stabilized. Moreover, it has high earthquake resistance against external impacts and the like, and can be easily assembled even when the dynodes 10 are stacked to assemble the electron multiplying unit 7, thereby improving the manufacturing efficiency of the entire apparatus. Further, by sealing the electron multiplying space inside the electron multiplying unit 7 together with the dynode 10 and the like, it is possible to suppress noise caused by the electrons coming out of the electron multiplying unit 7.

  Furthermore, the spacers 12a and 12b have a three-layer structure of insulating members 21A, 21B, and 21C, and include an intermediate wiring portion 24 including a resistor 28 formed on the insulating member 21B, a first wiring portion 22, and a second wiring. Since the portion 23 is covered with these insulating members 21A, 21B, and 21C, the wiring portion including the resistor 28 can be reliably surrounded by the insulator inside the spacers 12a and 12b, so that the detection sensitivity is stable. Can be In addition, since the wiring portion including the resistor 28 is collectively formed on the insulating member 21B, it is easy to form the conductive path 25 at the time of manufacturing, and the manufacturing efficiency of the entire device is improved. In addition, when creating the spacers 12a and 12b with the resistance value of the resistor 28 changed, it is possible to handle the spacers 12a and 12b by simply replacing the insulating member 21B. Can do. Furthermore, since the insulating members 21A, 21B, and 21C are joined by fusion of the insulating members without using an adhesive or the like, the influence of the adhesive or the like on the resistor 28 and each wiring portion can be reduced. There is no problem of outgassing.

  Furthermore, the protrusions 16c and 16d of the dynode 10 on the front stage side are fitted into the holes 19 on the front stage side of the spacer 12a, and the protrusion parts 16a and 16b of the dynode 10 on the rear stage side are fitted to the hole parts on the rear stage side of the spacer 12a. 19, the two-stage dynodes 10 and the conductive paths 25 of the spacers 12 a are electrically connected to each other, so that positioning between the dynodes 10 and between the dynodes 10 and the spacers 12 a is facilitated and at the same time reliable and stable. Electrical connection is made. A change in the positional relationship between the dynodes leads to a change in the output of each channel, and a change in the positional relationship between the dynode 10 and the spacer 12a indicates a change in the electrical connection state between them (for example, an electrical change caused by a change in the contact area at the connection portion). This also leads to a change in resistance), so that the detection sensitivity can be further stabilized.

  In addition, this invention is not limited to embodiment mentioned above. For example, the following various modifications can be employed as the shape of the conductive path formed in the spacer.

  11 to 13 show a spacer 112a which is a first modification of the present invention. In the spacer 112a, the first wiring part 122 is formed in a substantially L shape on the surface 26 of the insulating member 21B from the middle part of one side to the corner part 26b via the corner part 26a (see FIG. 12), the second wiring portion 123 is formed in a substantially L shape on the surface 27 of the insulating member 21B from the middle portion of one side to the corner portion 27b via the corner portion 27a (FIG. 13). ). These wiring parts 122 and 123 are connected by an intermediate wiring part 24 composed of the resistor 28 and the through hole 29. With reference to FIG. 14, the feeding direction between the dynodes when the spacer 112 a having the above configuration is arranged between two dynodes 10 will be described. As indicated by an arrow C in the figure, the protrusion 16c of the preceding dynode 10 and the hole 19 of the spacer 112a are connected, so that charge flows from the preceding dynode 10 into one corner of the spacer 112a. The electric charge flowing into the corner reaches the two holes 19 on the dynode 10 side in the subsequent stage via the first wiring part 122, the intermediate wiring part 24 including the resistor 28, and the second wiring part 123. Then, the electric charge that has reached the hole 19 flows through the protrusion 16b fitted in the hole 19 and flows into the dynode 10 on the rear stage side. Thus, the spacer 112a can also cause charge to flow between the two adjacent dynodes 10 via the resistor 28. Here, since one of the four corner holes 19 on each surface of the spacer 112a only needs to be connected to the dynode 10, the conductive coating may be omitted in the holes 19 at the other three corners. .

  FIG. 15 shows a spacer 212a which is a second modification of the present invention. In this spacer 212a, a conductive path 225 composed of two wiring portions and an intermediate wiring portion 24 including the resistor 28 and the through hole 29 is substantially straight from the middle portion of the side of the insulating member 21B to one corner portion. It is formed in a shape. The feeding direction between the dynodes when such a spacer 212a is used is as shown by an arrow D in FIG. Specifically, a charge flows from the dynode 10 at the front stage into one corner of the spacer 212a, and the charge is connected to the conductive path 225 including the resistor 28 and one hole 19 connected to the dynode 10 side at the rear stage. And then flows into the dynode 10 on the rear stage side. Also in this modified example, as in the first modified example, it is only necessary that one of the four corner hole portions 19 of each surface of the spacer 212a is connected to the dynode 10, and therefore, the hole portions in the other three corners. The interior of 19 may be omitted from the conductive coating.

  Further, like a spacer 312a which is a third modification of the present invention shown in FIGS. 17 and 18, a two-layer structure including the insulating members 21A and 21C is formed, and the bottom surface of the hole portion 19 formed in the insulating member 21A and A resistor 328 may be embedded between the bottom surface of the hole 19 formed in the insulating member 21C. Even with such a spacer 312a, adjacent two-stage dynodes 10 can be connected via a resistor. In this modification as well, a three-layer structure may be formed by embedding the resistor 328 in the insulating member 21B. Further, the resistor 328 may be embedded in all of the four corner holes 19 of each surface of the spacer 212a, or a part of the holes 19 may be used. In that case, the conductive coating may be omitted inside the hole 19 in which the resistor 328 is not embedded.

  Moreover, you may employ | adopt the 1 layer structure by an insulating member like the spacer 412a which is the 4th modification of this invention shown in FIG. In such a spacer 412a, at least the resistor 28 is selected from the surface 26 on which the first wiring portion 22 of the insulating member 21B is formed and the surface 27 on which the second wiring portion 23 and the intermediate wiring portion 24 are formed. Preferably, both surfaces 26 and 27 may be coated with an insulating material such as a glass material.

  In the case where the dynode is manufactured by etching and it is difficult to form the protrusion on the dynode, the protrusion may be formed on the spacer side, and the depression or hole may be formed on the dynode side. FIG. 20 is a perspective view of a spacer 512a which is a fifth modification of the present invention in such a case. In the spacer 512a shown in the figure, conductive protrusions 419 that are electrically connected to the wiring portions 425 are provided at the corners on different diagonal lines on both surfaces of the insulating member 21B, and the protrusions on both surfaces of the insulating member 21B. The region excluding the portion 419 is coated with a glass material. Even with such a structure, it is possible to connect the dynodes via the wiring portion 425 while preventing the resistance value of the resistor 28 from changing.

  Further, the arrangement relationship between the dynode 10 and the anode 8 in the photomultiplier tube 1 is not limited to that shown in FIG. 10, and one or more dynodes 10 may be arranged downstream of the anode 8. In that case, it is necessary to provide a separate resistor between the dynodes 10 on the front and rear sides of the anode 8. For example, a spacer made of only an insulator is provided between the anode 8 and the dynode 10 disposed on the front side and the rear side of the anode 8, and the stem pin 11 for the dynode 10 is connected to the front stage, the anode 8. It is connected to the dynode 10 on the front side and the rear side. By separately providing a resistor such as a bleeder resistor between the stem pin 11 connected to the dynode 10 on the front stage side of the anode 8 and the stem pin 11 connected to the dynode 10 on the rear stage side of the anode 8, Divide the voltage (divided voltage) to the dynode 10.

  In the embodiment described above, the photomultiplier tube is shown as the electron multiplier tube provided with the electron multiplier section. However, the electron multiplier tube having no other photocathode, the input light image has a luminance. It may be an electron multiplier provided with an electron multiplier such as an image multiplier to be amplified.

1 is an end view along the tube axis direction of a photomultiplier tube 1 according to a preferred embodiment of the present invention. It is a top view of the electron multiplication part containing the convergence electrode of FIG. It is a disassembled perspective view which shows a part of focusing electrode and electron multiplication part of FIG. It is a top view of the spacer of FIG. It is sectional drawing along the VV line of the spacer of FIG. It is sectional drawing along the VI-VI line of the spacer of FIG. It is the disassembled perspective view which looked at the spacer of FIG. 4 from upper direction. It is the disassembled perspective view which looked at the spacer of FIG. 4 from the downward direction. It is a disassembled perspective view which shows the electric power feeding direction between the dynodes of FIG. FIG. 2 is an assembly diagram of a focusing electrode, a dynode, and an anode of FIG. 1. It is a top view of the spacer concerning the 1st modification of the present invention. It is the disassembled perspective view which looked at the spacer of FIG. 11 from upper direction. It is the disassembled perspective view which looked at the spacer of FIG. 11 from the downward direction. It is a disassembled perspective view which shows the electric power feeding direction between dynodes at the time of using the spacer of FIG. It is a top view of the spacer concerning the 2nd modification of the present invention. It is a disassembled perspective view which shows the electric power feeding direction between dynodes at the time of using the spacer of FIG. It is a top view of the spacer concerning the 3rd modification of the present invention. It is sectional drawing along the VII-VII line of the spacer of FIG. It is the perspective view which shows the spacer concerning the 4th modification of this invention, (a) is the perspective view seen from one surface of the spacer, (b) is the perspective view seen from the other surface of the spacer. . It is a perspective view which shows the spacer concerning the 5th modification of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Photomultiplier tube, 2a ... Photocathode, 7 ... Electron multiplication part, 9 ... Electron multiplication hole, 10 ... Dynode, 12a, 12b, 112a, 212a, 312a, 412a, 512a ... Spacer, 16a, 16b, 16c, 16d ... projection, 18, 19 ... hole (first or second connecting part), 21A, 21B, 21C ... insulating member, 22, 122 ... first wiring part (wiring part), 23, 123 ... 2nd wiring part (wiring part), 24 ... intermediate wiring part (wiring part), 25, 225, 425 ... conductive path, 28, 328 ... resistor.

Claims (8)

An electron multiplier having an electron multiplier section in which dynodes, which are plate electrodes having electron multiplier holes for multiplying incident electrons, are stacked in a plurality of stages,
Between the adjacent two-stage dynodes, spacers that are insulating frame-like members each having a conductive path that electrically connects the two-stage dynodes are disposed,
A part of the conductive path is formed by a resistor covered with an insulator,
An electron multiplier characterized by that. The conductive path is
A first connection for electrically connecting to one of the two-stage dynodes;
A second connection for electrically connecting to the other of the two-stage dynodes;
A wiring portion covered with an insulator for electrically connecting the first connection portion and the second connection portion via the resistor;
The electron multiplier according to claim 1, comprising: The first connection part and the second connection part are plural.
The electron multiplier according to claim 2, wherein: The wiring part is
A first wiring portion connecting the plurality of first connection portions;
A second wiring portion connecting the plurality of second connection portions;
An intermediate wiring portion connecting the first wiring portion and the second wiring portion;
The resistor forms a part of the intermediate wiring portion.
The electron multiplier as claimed in claim 3. The spacer has a frame shape surrounding the region where the electron multiplier hole of the dynode is formed.
The electron multiplier as described in any one of Claims 1-4 characterized by the above-mentioned. A depression or a protrusion is formed in the first connection portion and the second connection portion,
Each of the two-stage dynodes is formed with at least one protrusion or depression,
The one dynode and the wiring portion are electrically connected by fitting the protrusion or the recess of one dynode of the two-stage dynodes to the recess or the protrusion of the first connection portion. And
The other dynode and the wiring portion are electrically connected by fitting the protrusion or the recess of the other dynode of the two-stage dynodes to the recess or the protrusion of the second connection portion. To be
The electron multiplier tube according to claim 2, wherein the electron multiplier tube is provided. The spacer is
A first insulating member provided on one dynode side of the two-stage dynodes and including the first connecting portion for electrically connecting to the one dynode;
A second insulating member provided on the other dynode side of the two-stage dynodes and including the second connecting portion for electrically connecting to the other dynode;
A third insulating member gripped between the first and second insulating members;
A first wiring portion provided between the first insulating member and the third insulating member and electrically connected to the first connecting portion;
A second wiring portion provided between the second insulating member and the third insulating member and electrically connected to the second connecting portion;
An intermediate wiring portion provided through the third insulating member and connecting the first wiring portion and the second wiring portion;
A part of the intermediate wiring part is formed of a resistor.
The electron multiplier according to claim 2 or 3, wherein The first wiring portion, the second wiring portion, and the intermediate wiring portion are formed on the third insulating member,
The electron multiplier according to claim 7.

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