JP2002203508A - Package for photomultiplier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress generation of a short circuit due to destruction of insulation between a base of a pin for a power supply and a flange of an upper face of a sidewall when a high voltage is inputted into the pin for the power supply without enhancing a height of a package. SOLUTION: This package for photomultiplier is equipped with a substrate 1 which is composed of an insulation material, wherein a concave part 2 to house a multiplier photomultiplier B is formed at the upper face and which has an electrode forming region 3 wherein plural electrodes 3a are formed at the central part of a bottom face 2a of the concave part 2, plural pins 3b for signals installed at the lower face of the substrate 1 and connected with the electrode 3a via a through conductor, a groove 4 formed at a circumference side outside the electrode forming region 3 of the bottom face of the concave part 2, a pin 5 for the power supply inserted top-and- bottom through the bottom face of the groove 4, and the flange 6 of a frame state joined to a periphery of an opening of the concave part 2 of the upper face of the substrate 1. Plural crimp parts 7 nearly in parallel to the bottom face of the concave 2 are formed top-and-bottom at the inner side of the circumference side of the groove 4, and an arithmetic mean coarseness of the end face 7a of the wall part 7 is 10 to 70 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a night vision device, an Auger electron spectrometer, and a photoelectron spectrometer (ESCA).
The present invention relates to a package for accommodating a photomultiplier tube applicable to an electron spectroscopic analyzer such as lysis) and a vacuum ultraviolet spectroscopic analyzer.

[0002]

2. Description of the Related Art In recent years, the characteristics of a photomultiplier tube have been dramatically improved by using a microchannel plate (hereinafter, referred to as MCP). A conventional photomultiplier tube package (hereinafter, referred to as a package) shown in FIG.
And a photomultiplier tube B using the MCP 100 as a dynode.

A metal flange 6 is joined to the upper surface of the side wall 2b of the base 1 via a conductor layer 2c such as a metallized layer and a brazing material. A lid 8 to which a light entrance window made of a material is fitted and joined is joined. In the center of the bottom surface 2a of the concave portion 2, an electrode forming region 3 is provided in which a plurality of electrodes 3a arranged in a matrix are formed. Further, on the lower surface of the base 1 on which the electrode formation region 3 is formed, there are provided signal pins 3b connected to the electrodes 3a via through conductors. Then, the photomultiplier tube B is placed on the electrode formation region 3, and thus the bottom surface 2 a, the side wall 2 b, and the lid 8 form
The recess 2 is hermetically sealed, and the inside of the recess 2 is maintained in a high vacuum state to function as a photomultiplier tube B.

A groove 4 is formed on the bottom surface 2 a of the concave portion 2 on the outer peripheral side of the electrode forming region 3.
A plurality of power supply pins 5 are vertically penetrated through the bottom surface 4a and inserted by brazing material. The power supply pins 5 are for supplying a voltage (bias voltage) for exciting the photoelectrons in the photomultiplier tube B, and a plurality of the power supply pins 5 are provided. A predetermined voltage from an external voltage source, for example, several kV to
10 kV is applied to the photomultiplier tube B to form an electric field for inducing photoelectrons moving in the photomultiplier tube B (moving from top to bottom in FIG. 5).

[0005] As shown in FIG. 4, the photomultiplier tube B causes the light incident window 10 of the package A to pass through the light incident window 104 of the cover 8 when passing through the light incident window 104.
Photoelectrons are emitted from the photocathode adhered inside 4 (inside of package A). Next, the photoelectrons are transferred to the MCP
A channel 101 made of a thin glass tube or the like of the MCP 100 is incident on the conductive film 102 on the
When passing through the inside while colliding with the inner wall, the photoelectrons are multiplied and the fluorescent layer 103 on the lower surface of the MCP 100 emits fluorescence.

The emitted fluorescent light is emitted to the outside through the emission window 105, enters a light receiving section (not shown) attached on the electrode 3a provided on the package A, and is converted into an electric signal. The electric signal is analyzed by an analyzer device such as an external computer device.

[0007] As shown in FIG. 4, the MCP 100 has a channel 101 composed of a number of extremely thin glass tubes.
The plate is sliced in the radial direction to form a plate, and has a structure in which, for example, a conductive film 102 and a phosphor layer 103 are respectively attached to the upper and lower surfaces of the plate.
The MCP 100 generates photoelectrons by the photoelectric effect of light incident on the conductive film 102 on the upper surface thereof. When the photoelectrons pass through the inside of the channel 101 while colliding with the inner wall of the channel 101, the secondary electrons are generated from the inner wall of the channel 101. Have the function of multiplying the number of electrons by letting out one after another by a chain reaction.

Therefore, the MCP 100 makes it possible to amplify and detect weak light by the above-mentioned multiplication action. The photomultiplier tube B using this MCP 100 has extremely high sensitivity and high-speed response. A fast time characteristic that cannot be obtained with any photomultiplier tube can be obtained. Also, the MCP 100
It has the function of a dynode as a plate.
Since each of the channels 101 constituting the CP 100 individually has a function as a dynode, the photomultiplier tube B using the same realizes better time characteristics than other photomultiplier tubes.

[0009]

However, in order to excite the electrons in the photomultiplier tube B, an electric field due to the application of a high voltage is required as described above, and the package A
Since it is indispensable to maintain the inside in a high vacuum atmosphere, the photomultiplier tube B has been conventionally used by being housed in a package made of resin or a package made of ceramics. Then, several kV to several tens of k are applied to the power supply pin 5.
When a voltage of V is applied, a short circuit occurs between the power supply pin 5 and the flange 6 on the upper surface of the side wall 2b of the package A via the inner side surface of the concave portion 2 due to the high voltage. At this time, since the flange 6 is held at a predetermined negative potential (−several 100 V) of the photocathode together with the lid 8, a short circuit easily occurs between the flange 6 and the power supply pin 5.

Such a short circuit is caused by the concave portion 2 of the package A.
5a where the power supply pin 5 contacts the bottom surface 4a of the groove 4 due to moisture, fine dust, dirt, etc. adsorbed on the inner surface of the groove 4
Is generated as a result of breaking the insulation between the two points of the flange 6 and the flange 6. In order to avoid this inconvenience, for example, the power supply pins 5 are formed by increasing the thickness of the bottom of the package A to increase the depth of the groove 4 or increasing the height of the side wall 2b. A portion 5 in contact with the bottom surface 4a of 4
A short-circuit is prevented by increasing the creepage distance from a to the flange 6. However, each of these configurations goes against the trend of reducing the height of the package A in recent years.

Accordingly, the present invention has been completed in view of the above problems, and an object of the present invention is to provide a method for applying a high voltage to a photomultiplier tube via a power supply pin, the power supply pin and a side wall of a package. It is an object of the present invention to eliminate the breakdown of the insulation between the upper surface flange and the flange due to the high voltage without increasing the height of the package.

[0012]

A package for a photomultiplier tube according to the present invention is made of an insulating material, has a concave portion for accommodating the photomultiplier tube formed on an upper surface, and has a plurality of concave portions formed at a central portion of a bottom surface of the concave portion. A base having an electrode formation region formed with a plurality of electrodes, a plurality of signal pins that are erected on the lower surface of the base and connected to the electrodes via through conductors, and the electrodes on the bottom surface of the concave portion A groove formed on the outer peripheral side from the formation region, a power supply pin inserted vertically through the bottom of the groove, and a frame-shaped flange joined to the periphery of the opening of the concave portion on the upper surface of the base; In the package for a photomultiplier tube, a plurality of folds substantially parallel to the bottom surface of the recess are formed on the inner surface on the outer peripheral side of the groove, and the arithmetic mean roughness of the end face of the fold is 10 to 70 μm. It is characterized by being.

According to the present invention, the creeping distance is lengthened at the fold portion and the arithmetic mean roughness of the end face of the fold portion is increased to 10 to 70 μm, thereby further substantially increasing the creepage distance. This can effectively prevent a short circuit between the portion where the power supply pin and the bottom surface of the groove are in contact and the flange on the upper surface of the side wall of the package. In addition, the folds can increase the creepage distance between the flange and the point where the power supply pin contacts the bottom of the groove and the flange, so that the height of the side wall of the package is reduced as long as a short circuit does not occur. As a result, the height of the package can be reduced.

[0014] In the present invention, preferably, the length of the fold formed below the upper end of the power supply pin from the inner side surface of the groove is longer than the upper end of the power supply pin. The length of the fold formed on the upper side may be shorter than the length of the groove protruding from the inner surface of the groove.

According to the present invention, the following problems can be solved by the above configuration. That is, there is a possibility that the power supply pin and the end face of the fold portion are too close to each other due to the variation in the formation position of the through hole into which the power supply pin is inserted, and the insulation may be broken. It is necessary to increase the distance from the end face of the portion, and as a result, it is possible to prevent the miniaturization of the package from being hindered.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The package A of the present invention will be described in detail below. 1 and 2 are a partial sectional view and a plan view of an embodiment of a package A of the present invention. FIG. 3 is a sectional view of a package A according to another embodiment of the present invention. FIG. 4 is an exploded sectional view schematically showing each part of the photomultiplier tube B. still,
The same members as those shown in the package A of FIG. 5 which is a conventional example are denoted by the same reference numerals.

In these figures, reference numeral 1 denotes an insulating material, in which a concave portion 2 for accommodating a photomultiplier tube B having an MCP 100 is formed on the upper surface, and a plurality of concave portions 2 are formed at the center of a bottom surface 2a of the concave portion 2. A substrate having an electrode forming region 3 on which an electrode 3a is formed, 2 is a concave portion, 2a is a bottom surface of the concave portion 2, 2b is a side wall of the concave portion 2, and 3 is a plurality of electrodes 3a in a central portion of the bottom surface 2a of the concave portion 2. Are formed on the lower surface of the base 1 and the electrode forming region 3b is formed.
a is a plurality of signal pins connected to a through a through conductor.

The photomultiplier tube B is a plate-shaped MCP 1
Since the creepage distance tends to be a problem in the case of a small-sized apparatus provided with the MCP 00, it is preferable to apply the configuration of the present invention to an apparatus provided with the MCP 100. Of course, the configuration of the present invention may be applied to another photomultiplier tube B.

Reference numeral 4 denotes a groove formed on the outer peripheral side of the electrode forming region 3 on the bottom surface 2a, 4a denotes a bottom surface of the groove 4, and 5 denotes a plurality of grooves inserted vertically through the bottom surface of the groove 4. The power supply pins 5 a are contact points between the power supply pins 5 and the bottom surface 4 a of the groove 4.

Further, reference numeral 6 denotes a frame-like flange joined to the periphery of the opening of the concave portion 2 of the package A via a conductor layer 2c. 7 denotes a bottom surface 2a of the concave portion 2 on the inner side surface on the outer peripheral side of the groove 4.
A plurality of folds formed substantially vertically above and below, 7a is an end face of the fold 7, 8 is a lid, 100 is an MCP, and B is a photomultiplier tube.

The fold 7 is formed with a groove 4 as shown in FIG.
It is preferable that the power supply pin 5 is formed at a position higher than at least the upper end of the power supply pin 5.

In the package A of the present invention, the photomultiplier tube B is mounted on the electrode forming region 3 in the recess 2 and functions as a package for the photomultiplier tube.

Then, as shown in FIG.
A photomultiplier tube B is provided at the center of the bottom surface 2a of the concave portion 2 of FIG. The photomultiplier tube B includes an MCP 100 as shown in FIG. 3 therein, for example, and a power supply for applying a high DC voltage to a groove 4 formed on a bottom surface 2a on the outer peripheral side from the lower surface side of the MCP 100. The pins 5 are provided so as to penetrate the bottom surface of the groove 4 and electrically connect the inside and outside of the package A. A signal pin 3b for extracting a signal from the electrode 3a is joined to the lower surface of the package. The signal pin 3b and the electrode 3a are electrically connected to each other by a through conductor such as a via hole filled with a conductor, which is provided vertically penetrating the bottom surface 2a of the concave portion 2 and the lower surface of the package A. . The signal pins 3b are connected to electrode pads formed on the lower surface of the package A by a brazing material or the like so as to be connected to the through conductors.

The base 1 having the side wall 2b surrounding the recess 2 is
Preferably, it is composed of a plurality of ceramic layers obtained by laminating and firing ceramic green sheets mainly composed of ceramic powder and a binder. And the fold 7 is the groove 4
Are formed on the inner side surface on the outer peripheral side so as to project substantially parallel to the bottom surface 2a at predetermined intervals in the vertical direction. That is, the folds 7 can be formed by alternately laminating frame-shaped ceramic green sheets having different shapes and dimensions of the through-holes at the center in the above-described ceramic lamination method.

By adjusting the thickness of the ceramic layer, the pitch of the arrangement of the folds 7 and the thickness thereof can be easily controlled. That is, when forming the through hole for the concave portion 2 in the center portion of the ceramic green sheet, the fold portion 7 prepares a ceramic green sheet having a small size of the through hole,
Next, the through holes are formed by alternately stacking large and small through holes. That is, at the arrangement position of the ceramic green sheets where the size of the through hole is small, the inner peripheral surface of the through hole becomes the fold 7 protruding into the recess 2.
On the upper surface of the side wall 2b, a flange 6 for joining a lid 8 having a light transmitting window made of a light transmitting material in the center is provided.
Is provided, and the lid 8 is joined to the flange 6 so that the MCP 100 accommodated inside the package A is provided.
Are hermetically sealed.

In the present invention, the arithmetic mean roughness of the end face 7a of the fold 7 protruding from the inner face of the side wall 2b is 10 to 70 μm.
In this case, the creepage distance of the end face 7a can be increased by the length along the uneven surface caused by the surface roughness. As a result, the creepage distance from the position of the power supply pin 5 to the flange 6 can be substantially reduced. Can be longer.

If the arithmetic mean roughness of the end face 7a is less than 10 μm, it is difficult to increase the creepage distance due to the unevenness of the end face 7a. If it exceeds 70 μm, fine cracks are formed on the end face 7a in the manufacturing process as shown below. It is easy to occur.

The arithmetic mean roughness of the end face 7a of the fold 7 is 10 to
In order to make the thickness 70 μm, for example, the clearance (gap) between the lower die and the pair of punches used for punching for forming a through hole is set to about 30 to 50 μm. do it. When the clearance is less than 30 μm, the arithmetic average roughness of the end face 7a is 10 μm.
m, and it is difficult to obtain the effect of increasing the creepage distance.

The clearance may vary depending on the thickness of the ceramic green sheet and the material thereof, and the punching characteristics may vary depending on these conditions. For example, in the case of a thick ceramic green sheet, the cut surface is likely to be roughened at the time of punching, so that in order to obtain the arithmetic average roughness on the end face 7a of the present invention, it is better to reduce the clearance within the above range. Good.

If the through-hole is punched in a state where the clearance exceeds 50 μm, a load is applied to the cut portion when the ceramic green sheet is punched, and fine cracks are easily generated on the punched end face 7a. The arithmetic average roughness of 7a exceeds 70 μm. In this case, even if a fine crack is generated on the end face 7a, the hermeticity of the package is not deteriorated. May impair the performance.

Therefore, when the through holes are formed in the ceramic green sheet by the punching method according to the above method, the folds 7
The arithmetic mean roughness of the end face 7a is 10 to 70 μm, and the airtightness of the package can be maintained well.

In the present invention, if the arithmetic average roughness of the end face 7a is, for example, 30 μm, the creepage distance in one ceramic layer becomes about twice as large as that of the arithmetic average roughness of 10 μm, The creeping distance from the creeping distance from 5 to the flange 6 is increased by several tens of percent. Accordingly, the withstand voltage also increases in proportion to this, so that the power supply pin 5 is moved from the portion 5a where it contacts the bottom surface 4a of the groove 4 to the side wall 2b without increasing the height from the lower surface of the base 1 to the upper surface of the flange 6. The creepage distance to the flange 6 on the upper surface can be increased. Therefore, a short circuit between the power supply pin 5 and the flange 6 can be effectively prevented.

The punching method in which the clearance between the lower die and the punch die is adjusted is applied to a ceramic green sheet that becomes a ceramic layer having a fold 7. Then, the ceramic green sheets and the green sheets punched out so that the arithmetic average roughness of the inner peripheral surface of the through hole is reduced to less than about 10 μm are alternately laminated in the formation portion of the fold portion 7, and then fired. And the fold 7 is the groove 4
The package A formed on the inner side surface of is formed.

It should be noted that the present invention is not limited to the above embodiment, and various changes may be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the folds 7 are formed by the ceramic lamination method. However, the base 1 is formed as a ceramic molded body by a molding method using a mold, and the folds are formed by firing and cutting, or by etching. The part 7 may be formed.

In the present invention, as shown in FIG. 3, the length of the fold 7b formed below the upper end of the power supply pin 5 from the inner side of the groove 4 is determined by the length of the power supply pin. 5
May be configured to be shorter than the protruding length of the fold 7c formed above the upper end of the groove 4 from the inner surface of the groove 4. In this case, the protruding length of the fold 7 b formed below the upper end of the power supply pin 5 from the side wall 2 b is formed above the upper end of the power supply pin 5. When the distance between the power supply pin 5 and the end face 7a of the fold 7b is too small, the fold 7b
It is possible to prevent a short circuit from occurring due to moisture or foreign matter adsorbed on the end face 7a.

Further, by increasing the length of the fold 7c formed above the position of the upper end of the power supply pin 5, it is formed below the position of the upper end of the power supply pin 5. The creeping distance between the flange 6 and the portion 5a where the power supply pin 5 and the bottom surface 4a of the groove 4 are in contact with each other can be increased by the length of the folded portion 7b or more. A short circuit between the pin 5 and the flange 6 can be effectively prevented.

[0037]

According to the present invention, there is provided an electrode forming region comprising an insulating material, a concave portion for accommodating a photomultiplier tube is formed on an upper surface, and a plurality of electrodes are formed at a central portion of a bottom surface of the concave portion. A plurality of signal pins erected on the lower surface of the substrate and connected to the electrodes via through conductors; a groove formed on the outer peripheral side of the electrode forming region on the bottom surface of the concave portion; and a bottom surface of the groove. And a frame-like flange joined to the periphery of the opening of the recess on the upper surface of the base, the inner surface on the outer peripheral side of the groove being substantially parallel to the bottom surface of the recess. A plurality of vertical folds are formed vertically and the arithmetic average roughness of the end face of the fold is 10 to 70 μm, so that the creepage distance between the base of the power supply pin and the flange can be increased without increasing the height of the package. The size of the power pin and side It made it possible to prevent a short circuit between the flange which is joined to the upper surface of the.

In the present invention, preferably, the protruding length from the inner surface of the groove of the fold formed below the upper end of the power supply pin is arranged above the upper end of the power supply pin. It is smaller than the protruding length from the inner surface of the groove of the formed fold. In this case, the power supply pin and the end face of the fold may be too close to each other due to the variation in the formation position of the through-hole into which the power supply pin is inserted, and the insulation may be destroyed. Although the distance between the fold and the end face must be increased, the length of the fold formed from the inner surface of the fold formed below the upper end of the power supply pin is shortened, so that the The hindrance to miniaturization can be eliminated.

Further, by increasing the length of the fold formed above the position of the upper end of the power supply pin, the fold formed below the position of the upper end of the power supply pin is increased. The creepage distance between the part where the power supply pin and the bottom of the groove contact and the flange can be increased by the length of the power supply pin or more, and the short circuit between the power supply pin and the flange can be effectively reduced. Can be prevented.

When the substrate is made of, for example, injection-molded ceramics, it is difficult to form the folds and further increase the surface roughness of the end faces of the folds. A fold having an end surface with a surface roughness can be formed by a ceramic green sheet laminating method without increasing the number of steps. Also, when forming the folds by the ceramic green sheet laminating method, a package can be formed by stacking and firing a plurality of frame-shaped ceramic green sheets having different through-hole sizes at the center, so that the folds are formed. No special manufacturing process is required for production, and therefore, low-cost, high-yield production is possible.
And it has excellent mass productivity.

Further, when the folds are formed by the ceramic green sheet laminating method, the folds can be densely arranged vertically, so that the package can be maintained while maintaining a creepage distance capable of preventing a short circuit. The height of the side wall of the package can be reduced, and the height of the package can be further reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an embodiment of a photomultiplier tube package of the present invention.

FIG. 2 is a plan view of the photomultiplier tube package of FIG. 1 excluding a lid and a photomultiplier tube.

FIG. 3 is an enlarged sectional view of a main part showing another example of the embodiment of the photomultiplier tube package of the present invention.

FIG. 4 is a schematic exploded sectional view of the photomultiplier tube.

FIG. 5 is a cross-sectional view of a conventional photomultiplier tube package.

[Explanation of symbols]

 1: Base 2: concave portion 2a: bottom surface 2b: side wall 3: electrode forming area 3a: electrode 3b: signal pin 4: groove 5: power supply pin 6: flange 7: fold 7a: end face of fold 8: lid 100: MCP A: Photomultiplier tube package B: Photomultiplier tube

Claims (2)

[Claims] 1. A substrate made of an insulating material, having a concave portion for accommodating a photomultiplier tube formed on an upper surface, and having an electrode forming region in which a plurality of electrodes are formed at a central portion of a bottom surface of the concave portion. A plurality of signal pins that are erected on the lower surface of the base and connected to the electrodes via through conductors; a groove formed on the bottom surface of the concave portion on the outer peripheral side from the electrode forming region; In a photomultiplier tube package comprising a power supply pin inserted vertically through the bottom surface of the base and a frame-shaped flange joined to the periphery of the opening of the concave portion on the upper surface of the base, an outer peripheral side of the groove is provided. A package for a photomultiplier tube, wherein a plurality of folds substantially parallel to the bottom surface of the concave portion are formed on an inner surface, and an arithmetic mean roughness of an end face of the fold is 10 to 70 μm. 2. The protruding length of the fold formed from the inner side surface of the groove below the upper end of the power supply pin is formed above the upper end of the power supply pin. 2. The photomultiplier tube package according to claim 1, wherein a length of the fold portion protruding from an inner side surface of the groove is shorter.