JP2000149861A - Photomultiplier tube, photomultiplier tube unit and radiation detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photomultiplier tube and a photomultiplier tube unit having an improved effective utilization area of a light-receiving face plate, and an enlarged fixing region of a bypass line on the light-receiving face plate, and to provide a radiation detection device having improved performance. SOLUTION: In this photomultiplier tube 1, the side face 3c of a light-receiving face plate 3 is projected to the outside relative to the outer wall face 2b of a metal bypass line 2, therefore, the light-receiving face plate 3 is projected to the side direction relative to the bypass line 2, to thereby enable to enlarge a light taking-in area from the light-receiving surface 3d of the light-receiving face plate 3. The projecting structure of the light-receiving face plate 3 like this is formed by paying attention to the refractive index of glass, and devised in order to take in the light, which is not received hitherto, into a photoelectric surface 3a as much as possible. And besides, when the metal bypass line 2 and the glass light-receiving face plate 3 are fixed together, a fusion technology is adopted because of joining between glass and a metal, and in order to guarantee certainty at the time of a joining work between the light- receiving face plate 3 and the bypass line 2, the projecting structure of the light- receiving face plate 3 is extremely effective.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photomultiplier tube having a structure in which weak light incident on a light receiving face plate is detected by multiplication of electrons, and a photomultiplier tube unit in which the photomultiplier tubes are arranged. And a radiation detector using a photomultiplier tube and a photomultiplier tube unit arranged side by side.

[0002]

2. Description of the Related Art Conventionally, as a technique in such a field, there is JP-A-5-290793. The photomultiplier tube described in this publication has a configuration in which an electron multiplier is housed in a sealed container, and the sealed container has a metal side tube formed with an upper end in a flange shape. The portion is fixed so as to be fused to the upper surface (light receiving surface) of the light receiving surface plate, thereby ensuring the airtightness by the flange portion. And
When fusing the flange portion of the side tube to the light receiving face plate, it was performed while heating the side tube.

[0003]

However, the above-mentioned conventional photomultiplier tube has the following problems. That is, as shown in FIG. 18, the side tube 100 has a flange portion 10 provided over the entire circumference at the upper end thereof.
1, the side tube 100 and the light-receiving surface plate 102 are fused and fixed so that the lower surface 101a of the flange portion 101 and the upper surface 102a of the light-receiving surface plate 102 are in contact with each other. In such a photomultiplier tube, the flange portion 101 has the light receiving face plate 1.
02 on the upper surface (light receiving surface) 102a,
As a result of the configuration in which the upper end of the side tube 100 covers the edge of the light receiving surface plate 102, there is a problem that the light receiving surface 102a is narrowed by the flange portion 101, and the effective use area of the light receiving surface plate 102 is reduced. In recent years, there are many occasions in which a large number of photomultiplier tubes are used side by side. In this case, it is required to increase the effective use area of the light receiving face plate 102 by even 1%. It is not difficult to imagine that when a large number of photomultiplier tubes are densely arranged, a considerable dead area is generated. In a radiation detector using such photomultiplier tubes in parallel, it is difficult to improve the performance of the detector itself due to the problem of the photomultiplier tube itself.

The present invention has been made to solve the above-mentioned problems, and in particular, a photomultiplier tube in which the effective area of the light receiving face plate is improved and the side tube fixing region in the light receiving face plate is enlarged. And a photomultiplier tube unit that facilitates control of the gain (current multiplication factor) in each electron multiplier in each side tube while improving the effective use area of the light receiving face plate. It is an object of the present invention to provide a radiation detection device in which the performance of the detection device itself is improved based on the enlargement.

[0005]

According to a first aspect of the present invention, there is provided a photomultiplier tube having a photoelectric surface for emitting electrons by light incident from a light receiving surface of a light receiving surface plate. A photomultiplier tube having an electron multiplier to be multiplied in a sealed container and having an anode for sending an output signal based on the electrons multiplied by the electron multiplier, wherein the sealed container is
A stem plate for fixing the electron multiplier and the anode via a stem pin, a metal side tube surrounding the electron multiplier and the anode and fixing the stem plate to one open end, A light-receiving surface plate made of glass fixed to the opening end on the side, and a side surface of the light-receiving surface plate is projected outward with respect to an outer wall surface of the side tube.

In this photomultiplier tube, as a result of projecting the side surface of the light-receiving surface plate outwardly with respect to the outer wall surface of the metal side tube, the light-receiving surface plate projects laterally with respect to the side tube. The light receiving area from the light receiving surface of the light receiving surface plate can be increased. Such a protruding structure of the light receiving surface plate is made by paying attention to the refractive index of the glass, and has been proposed in order to take in as much light that could not be received until now into the photoelectric surface. In addition, in fixing the side tube made of metal and the light receiving surface plate made of glass, a fusion technique is adopted because the glass and the metal are joined, but the reliability at the time of joining the light receiving surface plate and the side tube is ensured. Above, the overhang structure of the light receiving surface plate works extremely effectively. As described above, the overhanging structure of the light receiving face plate when the metal side tube is employed is an extremely effective means for enlarging the light receiving area and the fixing area at the time of fusion. Also, the thicker the light-receiving surface plate, the more effectively the overhanging structure of the light-receiving surface plate works in taking in light.

In the photomultiplier tube according to the present invention, it is preferable that a piercing portion buried on the photocathode side of the light receiving surface plate is provided at the upper end side of the side tube. In this case, the piercing portion provided on the side tube is embedded so as to pierce the light receiving surface plate made of glass, thereby contributing to an improvement in the familiarity between the side tube and the light receiving surface plate, and ensuring high airtightness. Moreover, the piercing portion provided on the side tube does not extend from the side tube toward the side like the flange portion, but extends so as to stand up from the side tube. In the case where the light receiving surface plate is buried so as to be as close as possible to the side surface, the effective use area of the light receiving face plate is increased as much as possible.

In the photomultiplier tube according to the third aspect, it is preferable that a reflection member is provided on a side surface of the light receiving face plate. In the past, light incident on the light receiving surface plate also escaped to the outside from the side surface, but such light is reflected by a reflecting member provided on the side surface to increase the amount of light that can be incident on the photoelectric surface. Thus, the efficiency of taking in light at the light receiving face plate is improved.

According to a fourth aspect of the present invention, there is provided a photomultiplier tube unit having a photoelectric surface for emitting electrons by light incident from a light receiving surface of a light receiving surface plate, and an electron multiplier for multiplying electrons emitted from the photoelectric surface. A photomultiplier tube unit having a plurality of photomultiplier tubes having an anode that sends out an output signal based on the electrons multiplied by the electron multiplying unit in a sealed container, A sealed container, a stem plate for fixing the electron multiplier and the anode via the stem pin, a metal side tube surrounding the electron multiplier and the anode, and fixing the stem plate to one open end, A light receiving surface plate made of glass fixed to the other open end of the side tube, a plurality of side tubes are juxtaposed, the light receiving surface plate is integrated, and the side tubes are separated from each other. .

In this unit, when the side tubes are juxtaposed, the light receiving surface plates are extended so as to bridge between adjacent side tubes by separating the side tubes while the light receiving surface plates are integrated. As a result, the effective use area of the light receiving face plate is increased. By integrating the light receiving surface plates, the light receiving surface plates can be set to the same potential, and the side tubes are separated from each other to facilitate control of the gain (current multiplication factor) in each electron multiplier. I have. For example, when the photocathode is used at a negative high voltage, it is necessary to finely adjust the gain of each electron multiplier in order to make the gain between the electron multipliers arranged side by side constant. However, this unit allows such gain control.

In the photomultiplier tube unit according to the fifth aspect, it is preferable that the plurality of side tubes be fixed to one light receiving face plate while being separated from each other. When such a configuration is adopted, the light receiving face plate is integrated by one light receiving face plate,
The quality of the light receiving face plate is made uniform, which contributes to the improvement of the reliability of the unit.

[0012] In the photomultiplier tube unit according to claim 6, it is preferable that the side surfaces of the plurality of light receiving face plates are fixed in surface contact with each other. When such a configuration is adopted, the light receiving face plates are joined to a single photomultiplier tube, thereby enabling a wide range of combinations with the single photomultiplier tube, and as a result, the unit can be made larger or smaller. In any case, it is possible to respond quickly.

[0013] In the photomultiplier tube unit according to claim 7, it is preferable that the side surfaces of the light receiving face plate are fixed via a conductive reflecting member. When such a configuration is adopted, while the conductivity of the light receiving surface plates is ensured by the reflection member, the amount of light that can be incident on the photocathode is increased by the reflection of light by the reflection member, and the light taking-in efficiency of the light reception surface plate Is improved.

According to an eighth aspect of the present invention, there is provided a radiation detecting apparatus according to the present invention, wherein a scintillator which emits fluorescence upon incidence of radiation generated from a subject, and a light receiving surface plate are arranged to face the scintillator, and a charge based on the fluorescence from the scintillator A plurality of photomultiplier tubes that output the same, and a position calculation unit that performs arithmetic processing on the output from the photomultiplier tube and outputs a position information signal of radiation emitted in the subject. The multiplier has a photocathode which emits electrons by light incident from the light receiving surface of the light receiving surface plate, and has an electron multiplying unit for multiplying the electrons emitted from the photocathode in the sealed container. The sealed container has an electron multiplier and a stem plate for fixing the anode via a stem pin, an electron multiplier, and an electron multiplier. A plurality of side tubes formed by a metal side tube surrounding the anode and fixing a stem plate at one open end, and a glass light receiving surface plate fixed to the other open end of the side tube. Are arranged side by side, the light receiving face plate is integrated, and the side tubes are separated from each other.

In this radiation detecting apparatus, when the side tubes are arranged side by side, the light receiving surface plates are integrated, and the side tubes are separated from each other so that the light receiving surface plates are bridged between the adjacent side tubes. Extend. As a result, the effective use area of the light receiving face plate is improved. By integrating the light receiving surface plates, the light receiving surface plates can be set to the same potential, and the side tubes are separated from each other to facilitate control of the gain (current multiplication factor) in each electron multiplier. I have. For example, when the photocathode is used at a negative high voltage, it is necessary to finely adjust the gain of each electron multiplier in order to make the gain between the electron multipliers arranged side by side constant. However, this device enables gain control, and as a result, improves the performance of the entire device.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a photomultiplier tube, a photomultiplier tube unit and a radiation detector according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view showing a photomultiplier according to the present invention, and FIG. 2 is a sectional view of FIG. The photomultiplier tube 1 shown in these drawings has a substantially square tube-shaped side tube 2 made of metal (for example, Kovar metal or stainless steel). A light-receiving surface plate 3 made of glass is fused and fixed.
A photocathode 3a for converting light into electrons is formed. The photocathode 3a is formed by reacting antimony previously deposited on the light receiving face plate 2 with alkali metal vapor. A metal (for example, Kovar metal or stainless steel) stem plate 4 is fixed to the open end B of the side tube 2 by welding. As described above, the side tube 2, the light receiving surface plate 3, and the stem plate 4 constitute the sealed container 5, and the sealed container 5 is an ultra-thin type having a height of about 10 mm.

A metal exhaust pipe 6 is fixed to the center of the stem plate 4. The exhaust pipe 6 is used to evacuate the inside of the sealed container 5 by using a vacuum pump (not shown) after the assembling work of the photomultiplier tube 1 is completed, and to form the photoelectric surface 3a. Sometimes it is also used as a tube for introducing alkali metal vapor into the sealed container 5.

In the sealed container 5, there is provided a block-shaped electron multiplier 7 of a stack type, and this electron multiplier 7 is formed by stacking ten (10-stage) plate-shaped dynodes 8. The electron multiplier 7 has a stem plate 4
Are supported in the sealed container 5 by a Kovar metal stem pin 10 provided so as to penetrate the dynode 8, and the tip of each stem pin 10 is electrically connected to each dynode 8. Further, the stem plate 4 is provided with a pin hole 4a for allowing each stem pin 10 to pass therethrough.
A tablet 11 used as a hermetic seal made of Kovar glass is filled, and each stem pin 10 is fixed to the stem plate 4 via the tablet 11. In addition,
Each of the stem pins 10 has a dynode and an anode.

Further, the electron multiplier 7 is provided with an anode 12 located below the electron multiplier 9 and fixed to the upper end of the stem pin 10 in parallel. At the uppermost stage of the electron multiplier 7, a flat focusing electrode plate 13 is disposed between the photocathode 3a and the electron multiplier 9, and the focusing electrode plate 13
, A plurality of slit-shaped openings 13a are formed, and each of the openings 13a is linearly arranged in one direction. Similarly,
In each dynode 8 of the electron multiplier 9, a plurality of slit-like electron multiplier holes 8a are formed in the same number as the openings 13a, and each electron multiplier hole 8a is linear in one direction and in a direction perpendicular to the paper surface. Multiple arrangements.

Each electron multiplying hole 8 of each dynode 8
a are arranged in a stepwise direction, and each electron multiplying path L
And the apertures 13a of the focusing electrode plate 13 correspond one-to-one with each other, so that the electron multiplier 7 has a plurality of channels. Further, 8 × 8 anodes 12 provided in the electron multiplier 7 are provided so as to correspond to a predetermined number of channels, and each anode 12 is connected to each stem pin 10 so that each stem pin 10 is connected. The individual output is taken out through the outside.

As described above, the electron multiplier 7 has a plurality of linear channels. Then, a predetermined voltage is supplied to the electron multiplier 9 and the anode 12 by a predetermined stem pin 10 connected to a bleeder circuit (not shown), and the photocathode 3a and the focusing electrode plate 13 are set to the same potential. The dynode 8 and the anode 12 are set to a high potential in order from the top. Therefore, the light incident on the light receiving surface plate 2 is converted into electrons on the photoelectric surface 3a, and the electrons are converted by the focusing electrode plate 13 and the first stage dynode 8 stacked on the uppermost stage of the electron multiplier 7. Due to the formed electron lens effect, the light enters the predetermined channel. Then, in the channel where electrons are incident,
The electrons pass through the electron multiplication path L of the dynode 8,
Each multi-stage is multiplied by each dynode 8 and incident on the anode 12, and an individual output is output to each anode 1 for each predetermined channel.
2 will be sent.

As shown in FIG. 3, when the metal stem plate 4 and the metal side tube 2 are hermetically welded, the stem plate 4 is inserted from the opening end B of the side tube 2, and The inner wall surface 2c of the lower end 2a of the base plate 4 abuts on the edge surface 4b of the stem plate 4,
The lower surface 4c of the stem plate 4 and the lower end surface 2d of the side tube 2 are substantially flush with each other so that the lower end surface 2d of the side tube 2 does not protrude from the stem plate 4. Therefore, the lower end 2a of the outer wall surface 2b of the side tube 2
Are extended substantially in the axial direction of the tube, and at the lower end of the electron multiplier 1, lateral protrusions such as flanges are eliminated. In this state, the joint portion F is irradiated with a laser beam from directly below the outer side or from a direction in which the joint portion can be aimed, and the joint portion F is laser-welded.

As described above, as a result of eliminating the protrusion like a flange at the lower end of the photomultiplier tube 1, resistance welding cannot be performed, but the outer dimensions of the photomultiplier tube 1 can be reduced, and the photomultiplier tube can be reduced. Even when the tubes 1 are used side by side, dead space can be eliminated as much as possible,
They can be arranged densely. Therefore, employing laser welding for joining the metal stem plate 4 and the metal side tube 2 enables the photomultiplier tube 1 to be thinner and to have a higher density array.

Such laser welding is an example of the fusion welding method. When the side tube 2 is fixed to the stem plate 4 by welding using this fusion welding method, unlike the resistance welding, the side tube 2 and the stem plate 4 are not fixed. Since there is no need to apply pressure to the joint portion F, no residual stress is generated in the joint portion F, cracks are less likely to occur in the joint portion even during use, and the durability and hermetic sealability are significantly improved. It is planned. Note that, among the fusion welding methods, laser welding and electron beam welding can suppress the generation of heat at the joint portion F to be smaller than resistance welding. Therefore, when assembling the photomultiplier tube 1, the influence of heat on the components arranged in the sealed container 5 is extremely reduced.

The side tube 2 is obtained by pressing a flat plate made of Kovar metal, stainless steel or the like into a substantially square cylindrical shape having a thickness of about 0.25 mm and a height of about 7 mm. A light-receiving surface plate 3 made of glass is fused and fixed to an opening end A on one side of the tube 2. As shown in FIG. 4, a piercing portion 20 that is melted and buried in the light receiving surface plate 3 side of the light receiving surface plate 3 by high-frequency heating is provided at a tip portion (upper end) of the side tube 2 on the light receiving surface plate 3 side. This piercing part 2
0 is provided over the entire circumference of the upper end of the side tube 2 and
Through the R-shaped portion 20a located on the inner wall surface 2c side,
It is formed so as to be bent outward. The tip 20b of the piercing portion 20 is sharpened like a knife edge. Therefore, the upper end of the side tube 2 is easily pierced into the light receiving surface plate 3, and when the side tube 2 is fused and fixed to the glass light receiving surface plate 3, the assembling operation is improved and reliability is improved.

In fixing the side tube 2 having the piercing portion 20 having such a shape to the light receiving surface plate 3, first, the back surface of the light receiving surface plate 3 is brought into contact with the tip 20 b of the piercing portion 20 of the side tube 2. In this state, the metal side tube 2 is placed on a turntable (not shown). Thereafter, the metal side tube 2 is heated by the high-frequency heating device. At this time, the light receiving face plate 3 is kept pressed from above by a pressing jig. Then, the piercing portion 20 of the heated side tube 2 advances while gradually melting the light receiving surface plate 3 made of glass. As a result, the piercing portion 20 of the side tube 2 is buried in the light receiving surface plate 3, and high airtightness is secured at a joint portion between the light receiving surface plate 3 and the side tube 2.

The piercing portion 20 does not extend sideways from the side tube 2 like a flange portion, but extends so as to stand up from the side tube 2. When the light receiving surface plate 3 is embedded so as to be as close as possible to the side surface 3c, the effective utilization area of the light receiving surface plate 3 can be increased to nearly 100%, and the dead area of the light receiving surface plate 3 can be made as close to zero as possible.

As shown in FIG. 5, the side surface 3c of the light receiving surface plate 3 made of glass projects outward by a predetermined amount from the outer wall surface 2b of the metal side tube 2, so that the light receiving surface plate 3 has a predetermined amount. An overhang portion 3A having an amount of protrusion L is formed.
Of the light receiving area from the light receiving surface 3d is increased.
Such an overhanging structure of the light receiving surface plate 3 is made by paying attention to the refractive index of the glass, and is intended to introduce a large amount of light 1 and light 2 that could not be received so far into the photoelectric surface 3a. In addition, it is a contrivance to make even a little light incident on the photocathode 3a. And, the thicker the light receiving face plate 3, the more effectively the overhang structure works in taking in light. It goes without saying that such a protrusion amount L is appropriately selected in relation to the thickness and the material of the light receiving face plate 3. The material of the light receiving face plate 3 includes Kovar glass, quartz glass and the like.

Further, in fusing and fixing the glass light receiving face plate 3 to the metal side tube 2, the above-mentioned fusion technique is adopted because the materials of glass and metal are joined. The overhang 3A of the light-receiving surface plate 3 acts very effectively in securing a fusion region during the joining operation between the light-receiving surface plate 3 and the side tube 2. By increasing the protrusion amount L of the overhang portion 3A, the side surface 3
c is less likely to sag, and the shape of the side surface 3c is reliably maintained.

As shown in FIG. 6, a reflecting member 21 may be provided on the side surface 3c of the light receiving face plate 3. This reflection member 2
1 is formed by depositing conductive aluminum on the side surface 3c. As a result of providing such a reflection member 21, in the related art, light incident on the light receiving face plate 3 has also escaped from the side surface 3 c to the outside. The amount of light that can be incident on the surface 3a is increased, and the efficiency of taking in light at the light receiving surface plate 3 is improved. In addition, the side tube 2 is provided with a piercing portion 20 </ b> A that can be pressed and bent inward.

Here, as shown in FIG. 7, in an overhang portion 3B as another example of the overhang structure of the light receiving surface plate 3, a side surface 3e of the light receiving surface plate 3 has a round portion K at a lower end. . The reflection member 22 is fixed to the side surface 3e. As shown in FIG. 8, the side surface 3f of the other overhang portion 3C has a linear cut-off shape. The reflection member 23 is fixed to the side surface 3f. As shown in FIG. 9, in still another overhang portion 3D, the side surface 3g has a round cutout shape. The reflecting member 24 is fixed to the side surface 3g. As described above, any of the side surfaces 3e to 3g is appropriate for improving the light taking-in efficiency. In particular, FIGS.
The side surfaces 3c and 3e shown in (1) can be said to be a configuration suitable for the case where the light receiving face plates 3 are closely attached and arranged side by side.

Next, a preferred embodiment of the photomultiplier tube unit and the radiation detector according to the present invention will be described.

As shown in FIG.
Is a gamma camera which is an example of this, and has been developed as a diagnostic device in nuclear medicine. The gamma camera 40 has a detection unit 43 held by an arm 42 extending from the support frame 39.
Is arranged directly above a bed 41 for placing a patient P as a subject.

In the housing 44 of the detector 43, FIG.
As shown in (1), a scintillator 46 is accommodated so as to face the affected part, and this scintillator 46 is directly fixed to the photomultiplier tube group G without a glass light guide. The photomultiplier tube group G includes a large number of photomultiplier tubes 1 arranged in a matrix at a high density. The light-receiving surface plate 3 of each photomultiplier tube 1 is directed downward to join the scintillator 46 face-to-face in order to directly enter the fluorescent light emitted from the scintillator 46. In this case, the light receiving face plate 3 is made thicker than the conventional light guide, so that the conventional light guide becomes unnecessary.

In the housing 44, each photomultiplier tube 1 is provided.
And a position calculation unit 49 for performing a calculation process based on the output electric charge from the X- and Y-signals for achieving a three-dimensional monitor on a display (not shown). And the Z signal are output. As described above, the gamma rays generated from the affected part of the patient P are converted into predetermined fluorescent light by the scintillator 46, and this fluorescent energy is converted into electric charge by each photomultiplier tube 1, and the position calculating part 4
By outputting the position information signal to the outside according to 9,
It enables monitoring of the energy distribution of radiation and is used for diagnosis on the screen.

Although the gamma camera 40 has been briefly described as an example of the radiation detecting apparatus, a positron CT (commonly known as PET) is used as a radiation detecting apparatus used for nuclear medicine diagnosis. It goes without saying that the tube 1 is used.

The photomultiplier tube group G is formed by arranging the photomultiplier tubes 1 having the same configuration in a matrix. As shown in FIG.
A photomultiplier tube unit S including four (2 × 2) photomultiplier tubes 1 is used. In the unit S, such an arrangement of the photomultiplier tubes 1 is an example.

Here, the matrix-shaped photomultiplier tube unit S will be described in detail.

In forming the unit S using the above-described photomultiplier tube 1, as shown in FIGS. 12 and 13, a photomultiplier tube 1 of the same shape is placed on a resin or ceramic substrate 50. Are arranged in a 2 × 2 row, the side surfaces 3 c of four adjacent light receiving face plates 3 are brought into close contact with each other, and the outer wall surfaces 2 b of the adjacent side tubes 2 are separated from each other. In this case, if the light receiving face plates 3 are fixed to each other via an adhesive, the light receiving face plates 3 can be fixed easily and reliably.

In this unit S, as shown in FIGS. 13 and 14, the light receiving face plate 3 having the overhang portion 3A is provided.
When the side surfaces 3c are aligned, the adjacent side tubes 2 can be inevitably separated from each other, and at the same time, the light receiving surface plate 3 extends so as to bridge the gap U formed between the adjacent side tubes 2. Will be there. Thus, the overhang 3
By using the photomultiplier tube 1 having A, the side tubes 2 can be separated from each other while improving the effective use area of the light receiving face plate 3. Then, by integrating the adjacent light receiving face plates 3 and separating the side tubes 2 from each other, the gain (current multiplication factor) control in each electron multiplier 9 via the stem pin 10 is facilitated. For example, when the photocathode 3a is used at a negative high voltage, the gain must be finely adjusted for each electron multiplier 9 in order to make the gain between the four electron multipliers 9 constant. However, the above-mentioned unit S enables this gain control.

In constituting the unit S,
As shown in FIG. 6, the side surfaces 3c of the adjacent light receiving face plates 3 are connected to each other by a reflection member 2 such as aluminum, MgO or Teflon tape.
1 may be fixed. In this case, the amount of light that can be incident on the photocathode 3a is increased by the reflection of the light by the reflection member 21, and the efficiency of taking in light at the light receiving surface plate is improved.

Incidentally, assuming that the side tubes 2 are separated from each other and the side surfaces 3c of the light receiving face plate 3 are integrated with each other, as shown in FIG. It may be fixed in a matrix.
As described above, when one light receiving surface plate 3S is employed, the quality of the light receiving surface plate 3S is made uniform, and at the same time, the reliability of the unit S is improved.

As another unit S1 in which a plurality of photomultiplier tubes 1 are arranged, as shown in FIG. 16, 25 side tubes 2 are arranged in a matrix on one light receiving face plate 3S.
It is also possible to configure 25 sealed containers 5. In this case, since one photoreceptor plate 3S is shared to constitute as many as 25 photomultiplier tubes 1, the photoreceptor plate 3S is separated by a glass cutter or the like at a desired position between adjacent side tubes 2. When cut, a unit composed of an arbitrary number of photomultiplier tubes 1 can be easily produced as required. Such a large unit S1 is suitable for producing the photomultiplier tube 1 in large quantities. For example, a large number of photomultiplier tubes 1 may be configured on one light receiving surface plate 3S, and the photomultiplier tubes 1 may be cut out and used one by one as needed.

The present invention is not limited to the embodiment described above. For example, as shown in FIG. 17, in the photomultiplier tube 1A, an outwardly extending flange portion 60a is provided at an upper end of the side tube 60, and an upper surface 60 of the flange portion 60a is provided.
c may be fused and fixed to the light receiving face plate 3. In this case, the side surface 3c of the light receiving face plate 3 projects outward with respect to the outer wall surface 60b of the side tube 60. Further, the shape of the light receiving face plate 3 is not limited to a square, but may be a polygon such as a rectangle or a hexagon.

[0046]

The photomultiplier according to the present invention has the following effects because it is constructed as described above. That is, it has a photoelectric surface that emits electrons by light incident from the light receiving surface of the light receiving surface plate, and has an electron multiplier for multiplying the electrons emitted from the photoelectric surface in a sealed container. In a photomultiplier tube having an anode that sends out an output signal based on the doubled electrons, the sealed container includes a stem plate for fixing the electron multiplier and the anode via a stem pin, and an electron multiplier and the anode. It is formed by a metal side tube that surrounds and fixes a stem plate to one open end, and a glass light receiving surface plate that is fixed to the other open end of the side tube. By protruding outward with respect to the outer wall surface of the tube, it is possible to increase the effective use area of the light receiving face plate and expand the fixing area of the side tube in the light receiving face plate.

The photomultiplier tube unit according to the present invention has a photocathode for emitting electrons by light incident from the light receiving surface of the light receiving face plate, and an electron multiplier for multiplying the electrons emitted from the photocathode. A photomultiplier tube unit in which a plurality of photomultiplier tubes having an anode for transmitting an output signal based on the electrons multiplied by the electron multiplier are arranged in a sealed container. Are a stem plate for fixing the electron multiplier and the anode via the stem pin, a metal side tube surrounding the electron multiplier and the anode and fixing the stem plate to one open end, and a side tube. A plurality of side tubes are arranged side by side, the light receiving surface plates are integrated, and the side tubes are separated from each other. Individual area while improving the use area To facilitate gain (current multiplication factor) control in the electron multiplier section in the tube.

Further, in the radiation detecting apparatus according to the present invention,
A scintillator that emits fluorescence by the incidence of radiation generated from the subject, a plurality of photomultiplier tubes that are arranged so that the light-receiving surface plate faces the scintillator, and outputs a charge based on the fluorescence from the scintillator, and a photomultiplier tube. And a position calculation unit that outputs a position information signal of radiation emitted in the subject, the photomultiplier tube converts electrons by light incident from the light receiving surface of the light receiving surface plate. An anode that has a photocathode for emitting light, has an electron multiplier for multiplying electrons emitted from the photocathode in a sealed container, and sends an output signal based on the electrons multiplied by the electron multiplier. The sealed container has a stem plate for fixing the electron multiplier and the anode via the stem pin, and surrounds the electron multiplier and the anode, and has a stem plate at one open end. A plurality of side tubes are formed side by side, and are formed by a metal side tube to be fixed and a glass light receiving surface plate fixed to the other open end of the side tube. , The performance of the detection device itself can be improved based on the expansion of the effective use area of the light receiving face plate.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a photomultiplier tube according to the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is an enlarged sectional view of a main part of FIG. 2;

FIG. 4 is an enlarged sectional view of a main part of FIG. 2;

FIG. 5 is a diagram showing a relationship between a light receiving surface plate and incident light.

FIG. 6 is a cross-sectional view showing a state in which a reflection member is provided on a light receiving surface plate.

FIG. 7 is a sectional view showing another embodiment of the light receiving face plate.

FIG. 8 is a sectional view showing still another embodiment of the light receiving face plate.

FIG. 9 is a sectional view showing still another embodiment of the light receiving face plate.

FIG. 10 is a perspective view showing an embodiment of the radiation detection apparatus according to the present invention.

FIG. 11 is a side view showing an internal structure of a detection unit used in the radiation detection device.

FIG. 12 is a plan view showing a photomultiplier tube unit.

FIG. 13 is a side view showing a photomultiplier tube unit.

FIG. 14 is an enlarged sectional view of a main part of FIG.

FIG. 15 is an enlarged sectional view of a main part of a photomultiplier tube unit using one light receiving face plate.

FIG. 16 is a perspective view showing another embodiment of the photomultiplier tube unit.

FIG. 17 is an enlarged sectional view of a main part showing another embodiment of the photomultiplier tube.

FIG. 18 is an enlarged sectional view of a main part showing a conventional photomultiplier tube.

[Explanation of symbols]

1, 1A: photomultiplier tube, 2, 60: side tube, 2b, 60
b: outer wall surface of side tube, 3, 3S: light receiving surface plate, 3a: photoelectric surface, 3c, 3e, 3f, 3g: side surface of light receiving surface plate, 3d ...
Light receiving surface, 3A to 3D ... overhang, 4 ... stem plate, 5 ...
Sealed container, 9: electron multiplier, 10: stem pin, 12 ...
Anode, 20, 20A ... piercing part, 21, 22, 2
3, 24: reflection member, 40: radiation detector, 46: scintillator, 49: position calculation unit, A, B: open end of side tube, S, S1: photomultiplier tube unit, P: patient (subject) .

Claims (8)

[Claims] An electron multiplying unit for multiplying electrons emitted from the photocathode in a sealed container, the photomultiplier having a photocathode which emits electrons by light incident from a light receiving surface of the light receiving face plate; In a photomultiplier tube having an anode that sends out an output signal based on the electrons multiplied by the multiplier, the sealed container includes a stem plate that fixes the electron multiplier and the anode via a stem pin. A metal side tube that surrounds the electron multiplier and the anode and fixes the stem plate at one open end; and the glass light receiver that is fixed to the other open end of the side tube. A photomultiplier tube formed by a face plate, wherein a side surface of the light receiving face plate projects outward with respect to an outer wall surface of the side tube. 2. The photomultiplier tube according to claim 1, wherein a piercing portion embedded on the photocathode side of the light receiving face plate is provided on an upper end side of the side tube. 3. The photomultiplier tube according to claim 1, wherein a reflection member is provided on the side surface of the light receiving face plate. 4. An electron multiplying unit having a photocathode for emitting electrons by light incident from a light receiving surface of a light receiving face plate, and an electron multiplying unit for multiplying the electrons emitted from the photocathode in a sealed container. In a photomultiplier tube unit in which a plurality of photomultiplier tubes each having an anode for transmitting an output signal based on the electrons multiplied by the multiplier are arranged in parallel, the sealed container includes the electron multiplier and the electron multiplier. A stem plate for fixing the anode via a stem pin, a metal side tube surrounding the electron multiplier and the anode, and fixing the stem plate to one open end; A plurality of the side tubes are arranged side by side, the light receiving surface plates are integrated, and the side tubes are separated from each other. Photomultiplier tube unit. 5. The light receiving face plate according to claim 4, wherein a plurality of said side tubes are fixed in a state of being separated from each other.
A photomultiplier tube unit as described. 6. The method according to claim 6, wherein the side surfaces of the plurality of light-receiving surface plates are arranged in
5. The fixing device according to claim 4, wherein the fixing members are fixed to each other.
A photomultiplier tube unit as described. 7. The light receiving face plate according to claim 6, wherein the side faces of the light receiving face plate are fixed via a conductive reflecting member.
A photomultiplier tube unit as described. 8. A scintillator which emits fluorescence by incidence of radiation generated from a subject, and a plurality of photomultiplier tubes which are arranged so that a light-receiving surface plate faces the scintillator and which outputs a charge based on the fluorescence from the scintillator. And a position calculation unit for calculating the output from the photomultiplier tube and outputting a position information signal of the radiation emitted in the subject. The photomultiplier tube includes: A photocathode that emits electrons by light incident from the light receiving surface of the face plate, and an electron multiplier that multiplies the electrons emitted from the photocathode in a sealed container, and multiplies with the electron multiplier. An anode for transmitting an output signal based on the generated electrons; the sealed container, a stem plate for fixing the electron multiplier and the anode via a stem pin; A metal side tube that surrounds the electron multiplier and the anode, and fixes the stem plate at one open end, and the glass light receiving surface plate that is fixed to the other open end of the side tube. A radiation detection apparatus comprising: a plurality of side tubes arranged side by side; a light receiving surface plate integrated with the side tubes; and the side tubes separated from each other.