JPH10214589A - Electron multiplier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron multiplier having high resistance against a mechanical shock and high reliability. SOLUTION: In an electron multiplier 1, in consideration that a glass bulb body 2 is fixed to a stem 5 and stem pins 10 are secured to the stem 5, a material including ceramic is used for the stem 5, thereby increasing mechanical strength of the stem 5. The use of the stem 5 made of the ceramics material makes the entire stem 5 opaque and allows a noise beam to be shielded. Consequently, it is unnecessary to cover the stem 5 with a beam shielding member in some cases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron multiplier having an electron multiplier for multiplying electrons.

[0002]

2. Description of the Related Art In a conventional photomultiplier tube, an entrance window having a photocathode is provided on one side of a glass bulb body (envelope). On the other side, a disk-shaped glass stem to which a metal stem pin is fixed is provided. In addition, an electron multiplier composed of a plurality of stages of dynodes for sequentially multiplying photoelectrons emitted from the photocathode is arranged between the entrance window and the stem. The valve body, stem pin, and stem that are joined to each other by thermal fusion have the same coefficient of thermal expansion. As described above, when the members having the same coefficient of thermal expansion are fusion-bonded to each other, it is difficult for the glass valve body or stem to be cracked or chipped at the bonded portion. Generally, the thermal expansion coefficient is about 47 × 10
The material of ^-7 / ℃ is frequently used.

[0003]

However, since the conventional electron multiplier is configured as described above, there are the following problems. That is, since the electron multiplier has a structure in which the whole is wrapped in glass, it is vulnerable to mechanical shocks such as impacts, requires sufficient care in handling, and its handling workability is not very good. Further, when the stem is provided with a light shielding property, Japanese Patent Application Laid-Open No.
As described in Japanese Patent No. 222178, it is necessary to employ colored glass for the stem, which has led to an increase in cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a highly reliable electron multiplier that is particularly resistant to mechanical shock.

[0005]

According to a first aspect of the present invention, there is provided an electron multiplier according to the present invention, wherein a stem is fixed to an end portion of a glass bulb body, and a voltage applied from a metal stem pin which is erected on the stem. In the electron multiplier, the electrons are multiplied by the electron multiplier in the valve body, and the electrons multiplied by the electron multiplier are collected as an output signal at the anode. It is characterized by being formed of a transparent glass.

In this electron multiplier, attention was paid to the fact that the valve body was fixed to the stem and the stem pin was also fixed to the stem. As a result of trial and error in increasing the mechanical strength of the stem, a stem containing ceramic was adopted. And
The mechanical strength of the entire electron multiplier is increased. Then, as a result of including the ceramic in the stem, the entire stem becomes opaque, and noise light can be blocked by the stem. Therefore, it is not necessary to surround the stem with the light shielding member depending on the situation.

In this case, it is preferable to form a positioning projection or recess integrally on the outer surface of the stem. The integral formation of such a projection or a concave portion with the stem is achieved when the mechanical strength of the stem itself is high. When the concave portion is formed, the possibility that the convex portion or the concave portion is chipped increases. Then, by forming a positioning convex or concave portion on the stem, for example, after the stem pin is inserted into the socket, it is used for positioning the stem.

It is preferable that the thermal expansion coefficients of the valve body and the stem pin are substantially the same, and the thermal expansion coefficient of the stem is made smaller than these thermal expansion coefficients. When such a configuration is adopted, the workability and the joining property when the stem and the valve body and the stem and the stem pin are fusion-bonded to each other are improved while maintaining the mechanical strength of the stem increased.

Further, it is preferable that the thermal expansion coefficient of the stem be smaller than the thermal expansion coefficient of the stem pin, and the thermal expansion coefficient of the valve body be smaller than the thermal expansion coefficient of the stem.
When such a configuration is adopted, the stem and the valve body, while maintaining the state where the mechanical strength of the stem is increased,
The workability and the joining property when the stem and the stem pin are fused and joined are improved.

[0010] Further, it is preferable that the rows of the stem pins are two linear and parallel rows. When such a configuration is adopted, each stem pin can be directly connected to an in-line type socket having a connect portion arranged in series.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an electron multiplier according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view showing a photomultiplier as an example of the electron multiplier according to the present invention. The head-on type photomultiplier tube 1 shown in FIG. 1 has a cylindrical valve body 2 made of glass, and an entrance window 3 is integrally formed at one end of the valve body 2 by blow molding or the like. On the inner surface of the window 3, a photoelectric surface 4 for converting light into electrons is formed. The other end of the valve body 2 has a disk-shaped stem 5 made of glass.
The stem 5 is fused and fixed to the valve body 2. Also, between the entrance window 3 and the stem 5,
An electron multiplier 7 having a plurality of stages of dynodes 6 for sequentially multiplying the photoelectrons emitted from the photocathode 4 is disposed, and the photocathode 4 is provided between the electron multiplier 7 and the entrance window 3. A disk-shaped focus electrode (disk electrode) 8 for reliably guiding the photoelectrons emitted from the dynode 6A to the first stage dynode 6A is arranged, and the anode portion 9 is arranged so as to face the final stage dynode 6B. Are located. And stem 5
A plurality of stem pins 10 made of metal (made of Kovar metal) arranged in a circle are fixed, and the tip of each stem pin 10 is connected to the electron multiplier 7 in the valve body 2.

Here, the stem 5 is formed of an opaque glass material containing ceramics. As a result, the mechanical strength of the stem 5 itself is increased, and the stem 5 can block a desired noise light. Further, the thermal expansion coefficient of the Kovar metal stem pin 10 and that of the Kovar glass valve body 2 containing no ceramics are set to be substantially the same, and the stem 5 serving as an intermediary between the stem pin 10 and the valve body 2 is formed. The thermal expansion coefficient is set smaller than the thermal expansion coefficients of the stem pin 10 and the valve body 2. As a result, workability and joining performance when the stem 5 and the valve body 2 and the stem 5 and the stem pin 10 are fusion-bonded are improved. For example, the thermal expansion coefficients of the stem pin 10 and the valve body 2 are:
By setting to 47 × 10 ⁻⁷ / ° C., which is commonly used, versatility is increased, and the stem 5 has a thermal expansion coefficient of 43 × 10 ⁻⁷ / ° C.
It is preferable to set the temperature to × 10 ⁻⁷ / ° C. and at the same time to form the substrate from Kovar glass containing Al ₂ O ₃ .

Next, a modified example in which the stem 5 made of opaque glass containing ceramic is applied to the stem pin 10 and the valve body 2 will be described. The thermal expansion coefficient of the stem 5 is set smaller than the thermal expansion coefficient of the stem pin 10 made of Kovar metal, and the thermal expansion coefficient of the valve body 2 made of Kovar glass which does not contain ceramics is made smaller than the thermal expansion coefficient of this stem 5. Set smaller. By setting the coefficient of thermal expansion in this way, the coefficient of thermal expansion of the stem 5, which acts as an intermediary between the stem pin 10 and the valve body 2, is determined by the coefficient of thermal expansion of the stem pin 10 and the coefficient of thermal expansion of the valve body 2. Between the stem 5 and the valve main body 2 and between the stem 5 and the stem pin 10 by fusion welding. For example,
The thermal expansion coefficient of the stem pin 10 is set to 47 × 10 ⁻⁷ / ° C., which is commonly used, to increase versatility, and the stem 5 has its thermal expansion coefficient set to 43 × 10 ⁻⁷ / ° C. At the same time, the valve body 2 is made of Kovar glass containing Al ₂ O ₃ , and its coefficient of thermal expansion is 40 × 10 ⁻⁷ /
It is preferable that the temperature is set to 0 ° C. and the fusion bonding property with the stem 5 is considered.

Further, since the mechanical strength of the stem 5 can be increased, even if irregularities are formed on the surface of the stem 5, the stem 5 is not chipped or broken, and the versatility of the stem 5 is enhanced. For example, as shown in FIG. 2, two hemispherical protrusions 11 are formed on the outer surface 5a of the stem 5 by integral molding, and these protrusions 11 are arranged on both sides of the intake pipe 12 to be connected. It can be used for positioning with respect to an object (for example, an IC socket 13 described later). For example, as shown in FIG.
The two hemispherical concave portions 14 are formed on the joint surface 13a of each of these. These concave portions 14 are arranged on both sides of the exhaust pipe insertion hole 15 and have a position and a shape that fit with the convex portion 11 of the stem 5. Have. Therefore, when the outer surface 5a of the stem 5 and the joining surface 13a of the IC socket 13 are aligned, the exhaust pipe 12 protruding from the stem 5 is inserted into the exhaust pipe insertion hole 15 of the IC socket 13, and the protrusion 11 of the stem 5 Is IC
It is inserted into the recess 14 of the socket 13. Therefore, IC
The positioning of the stem 5 with respect to the socket 13 is ensured.

The plurality of stem pins 10 fixed to the stem 5 are linearly arranged in two parallel rows, so that the exposed portions 10a of the stem pins 10 protruding outside from the stem 5 are arranged in two parallel rows. Become. Therefore, IC socket 1
The exposed portions 1 of the stem pins 10 are connected to the connecting portions 16 linearly arranged as two rows parallel to the joining surface 13a of
0a can be directly connected. in this case,
By inserting the projection 11 of the stem 5 into the recess 14 of the IC socket 13, the position of the photomultiplier tube 1 with respect to the IC socket 13 is stabilized. It is important that the arrangement interval of the exposed portions 10a in each of the rows A and B matches the predetermined arrangement interval of each of the connect portions 16.

The present invention is not limited to the embodiment described above. For example, a concave portion may be formed in the stem 5 instead of the convex portion 11 formed in the stem 5. in this case,
It goes without saying that a convex portion is formed on the joint surface 13a instead of the concave portion 14 formed on the joint surface 13a of the IC socket 13. In addition, the shapes of the convex portions 11 and the concave portions 14 are not limited to hemispherical shapes, and may be cylindrical, conical, triangular pyramid, triangular pyramid,
It may be a quadrangular prism, a polygonal prism, or a polygonal pyramid. When the positioning projections 11 are applied, the arrangement of the exposed portions 10a in the stem pin 10 may be linear or circular. Needless to say, the configuration of the photomultiplier tube 1 described above can be applied to an electron multiplier tube having no photocathode 4.

[0018]

As described above, the electron multiplier according to the present invention has the following effects. That is, a stem is fixed to an end of a glass bulb body, and electrons are multiplied in an electron multiplier section in the bulb body by an applied voltage from a metal stem pin erected on the stem. In the electron multiplier, which collects the electrons multiplied by the output signal at the anode as an output signal, the stem is formed from opaque glass containing ceramics, which enhances mechanical shock and improves handling. As a result, a highly reliable electron multiplier can be produced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a head-on type photomultiplier as an example of an electron multiplier according to the present invention.

FIG. 2 is a perspective view of a stem viewed from below.

FIG. 3 is a perspective view showing a stem to which a stem pin is fixed and a socket.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photomultiplier tube 2 ... Valve body 5 ... Stem 5a
... Stem outer surface, 7 ... Electron multiplier, 9 ... Anode, 10
... Stem pins, 11 ... Positions for positioning.

Claims (5)

[Claims] 1. A stem is fixed to an end of a glass bulb main body, and electrons are multiplied by an electron multiplying section in the bulb main body by a voltage applied from a metal stem pin erected on the stem. An electron multiplier wherein the electron multiplied by the electron multiplier is collected as an output signal at an anode section, wherein the stem is formed of an opaque glass containing ceramics. 2. The electron multiplier according to claim 1, wherein a projection or a recess for positioning is integrally formed on an outer surface of said stem. 3. The thermal expansion coefficient of the valve body and the stem pin is substantially the same, and the thermal expansion coefficient of the stem is made smaller than the thermal expansion coefficient of the stem body. Electron multiplier. 4. The thermal expansion coefficient of the stem is made smaller than the thermal expansion coefficient of the stem pin, and the thermal expansion coefficient of the valve body is made smaller than the thermal expansion coefficient of the stem. 3. The electron multiplier according to 1 or 2. 5. The electron multiplier according to claim 1, wherein the rows of the stem pins are linear and two parallel rows.