JPH0613020A - Semiconductor ceramic composition for secondary-electron multiplication device - Google Patents

Abstract

PURPOSE:To provide a secondary-electron multiplication device of stable operation, which has no possibility of thermal runaway due to heating even when a resistance value is reduced by providing a semiconductor ceramic composition, in which coefficient (delta) of secondary electron emission is high, and which has a flat or positive temperature characteristic of resistance. CONSTITUTION:A fixed amount of nickel oxide is added to a principal component consisting of zinc oxide and titanium oxide, to provide a composition of 55-80mol% of zinc oxide, 12-30mol% of titanium oxide, and 0.2-20mol% of nickel oxide.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a semiconductor ceramic composition for a secondary electron multiplier.

[0002]

2. Description of the Related Art Conventionally, as a secondary electron multiplying apparatus using a semiconductor porcelain, for example, a cylindrical semiconductor porcelain provided with electrodes at necessary places (Japanese Patent Publication No. 48-18026),
Electrodes provided at both ends of a plate-shaped semiconductor porcelain, and a plurality of holes provided perpendicularly to both electrodes (JP-B-48-18029), and a bundle of cylinders of the same length (JP-B-48).
No. 18030), but zinc titanate-based semiconductor porcelain is adopted as the material.

Specific compositions of this zinc titanate-based semiconductor porcelain include ZnO 72.5 mol% and TiO ₂ 27.5.
A semiconductor porcelain composed of mol% and a semiconductor porcelain composed of ZnO 72.5 mol%, TiO ₂ 27.5 mol% and Al ₂ O ₃ 1.25 mol% are shown, and the former material has a resistivity of 8 ×.
It is said that 10 ⁶ Ω · cm is obtained, and that the latter material has a resistivity of 2.8 × 10 ⁶ Ω · cm.

[0004]

However, the zinc titanate-based semiconductor porcelain can be sufficiently applied to the secondary electron multiplier as long as the purpose is mainly to detect a very small amount of charged particles, but in recent years, it has been used. The environment becomes harsh, and it is required to perform detection from a very small amount to a large incident current with one detector, and the secondary electron multiplier has a wide proportional range between the incident current and the output current, that is, a wide dynamic range. However, there has been a problem that the range of use is limited because of the increasing demand. That is, it is generally said that in a channel type secondary electron multiplier, the amount of output current that can be taken out linearly with respect to the incident current is 10% of the current flowing through the element, that is, the element current. Therefore, in order to increase the output current, it is necessary to increase the element current. However, since the zinc titanate-based semiconductor porcelain has a negative temperature coefficient of resistance, the resistance value is significantly reduced to increase the dynamic range. Then, a vicious cycle is repeated in which heat is generated and the resistance value decreases, which causes further heat generation and further lowers the resistance value, eventually causing so-called thermal runaway and unable to maintain a high voltage, expanding the dynamic range. However, there is a problem that the range of use is limited.

Therefore, the present invention provides a semiconductor porcelain composition having a large secondary electron emission coefficient (δ) and a flat or positive resistance-temperature characteristic, and thermal runaway due to heat generation even if the resistance value is reduced. It is an object of the present invention to obtain a stable secondary electron multiplying device which is free from the fear of operation.

[0006]

[Means for Solving the Problems] As a means for solving the above problems, the present invention comprises adding a predetermined amount of nickel oxide to a main component composed of zinc oxide and titanium oxide to obtain zinc oxide in an amount of 55 to 80 mol% and oxidized. It has a composition of 12 to 30 mol% titanium and 0.2 to 20 mol% nickel oxide.

[0007]

[Function] When nickel oxide is added to the zinc oxide-titanium oxide-based semiconductor porcelain, not only the specific resistance and the gain increase, but also the zero or positive temperature coefficient of resistance comes to be exhibited, which significantly reduces the resistance value of the element. However, thermal runaway does not occur and operation in high vacuum is stable. The reason why the semiconductor porcelain composition according to the present invention is limited to the above composition range is that when the amount of nickel oxide added is less than 0.2 mol%, the effect cannot be sufficiently obtained, and when it exceeds 20 mol%, the specific resistance is increased. Is reduced.

Hereinafter, examples of the present invention will be described.

[0009]

[Examples] Powders of zinc oxide, nickel oxide and titanium oxide were used as raw materials, and these were compounded so as to obtain a semiconductor porcelain having a composition ratio shown in Table 1. The obtained mixture was put together with agate stones and pure water in a pot mill internally laminated with polyethylene, wet pulverized for 20 hours, mixed, dehydrated, dried, pulverized to 50 to 200 mesh and sized.

To each of the obtained powders, a binder made of wheat flour paste and paraffin was added to obtain a plastic, which was extrusion-molded to obtain a tubular molded body. This molded product was lined up on the raw material of the co-fabric laid on an alumina box, and fired for about 1 hour at a temperature shown in Table 1 in an electric furnace in a natural atmosphere to give an outer diameter of 2.0 m.
A cylindrical semiconductor ceramic sample having an m, an inner diameter of 1.0 mm and a length of 50.0 mm was obtained.

The specific resistance, multiplication gain and resistance temperature characteristic of the obtained sample were measured. The results are shown in Table 1.
The specific resistance was determined by applying a voltage of 30 V / mm at room temperature to obtain the specific resistance at room temperature.

Regarding the multiplication gain, the experimental circuit shown in FIG. 1 was used, and as shown by the dotted line, the cylindrical semiconductor ceramic 1
Except a DC power source 4 connected to electrodes 2 and 3 formed on both ends of the filament, a filament power source 6 for heating a filament 5, an electron acceleration power source 7, a collector power source 9 connected to a collector 8, and an electron counter 10. All were installed in a vacuum, the degree of vacuum was 1.0 × 10 ^-6 Torr, the DC power supply was 3 kV, the electron acceleration power supply 7 was 200 V, and the electrons emitted from the filament 5 were cylindrical semiconductor porcelain 1. Of the secondary electron multiplying gain by measuring the number of pulses by the electron counter 10 by receiving the multiplied electrons by the collector 8 and multiplying them by colliding with the wall surface in the cylinder for multiplication. .

The temperature characteristic of the resistance value was measured by placing the sample in a constant temperature bath, increasing the temperature by 10 ° C. from room temperature in sequence, applying a voltage of 30 V / mm at each temperature, and measuring the resistance against temperature change. The change of the value is plotted as a function of temperature as shown in FIG. 9, where the resistance value increases as the temperature increases (a), the resistance value becomes almost flat (b), and the resistance value decreases (c). The results are shown in Table 1.

[0014]

[Table 1] Main component (mol%) Firing temperature Resistivity Gain characteristics No. ZnO TiO ₂ NiO ℃ (Ω ・ cm) at 3KV Curve 1 74 26 0 1380 2.8 × 10 ⁵ 2.0 × 10 ⁶ c 2 55 31 14 1330 ∞ 3 55 28 17 1330 6.3 × 10 ⁸ 2.5 × 10 ⁸ a 4 55 25 20 20 1320 3.8 × 10 ⁸ 3.3 × 10 ⁶ a 5 60 32 32 8 1360 ∞ 6 60 29 11 11 1360 1.5 × 10 ⁹ 2.1 × 10 ⁶ a 7 60 26 14 14 1320 7.7 x 10 ⁸ 2.8 x 10 ⁶ a 8 60 23 23 17 1320 3.4 x 10 ⁸ 3.1 x 10 ⁶ a 9 60 20 20 1320 9.2 x 10 ⁷ 3.0 x 10 ⁶ a 10 60 17 23 23 1300 4.6 x 10 ⁷ 3.2 x 10 ⁶ a 11 65 32 3 1360 ∞ 12 12 65 30 5 1360 1.1 × 10 ⁹ 1.5 × 10 ⁶ b 13 65 27 27 8 1360 8.7 × 10 ⁸ 2.4 × 10 ⁶ b 14 65 24 11 1360 1.3 × 10 ⁸ 3.2 × 10 ⁶ a 15 65 21 14 1320 2.4 x 10 ⁷ 2.8 x 10 ⁶ a 16 65 18 17 1320 6.7 × 10 ⁶ 2.4 × 10 ⁶ a 17 65 15 20 1320 4.0 × 10 ⁵ 3.6 × 10 ⁶ a 18 65 12 12 23 1300 3.8 × 10 ⁴ 3.2 × 10 ⁶ a 19 70 273 3 1360 3.6 × 10 ⁴ 1.0 × 10 ⁶ b 20 70 25 5 1360 8.7 × 10 ⁷ 2.1 × 10 ⁶ b 21 70 22 22 1360 2.5 × 10 ⁷ 3.0 × 10 ⁶ b 22 70 19 19 11 1320 8.9 × 10 ⁶ 3.2 × 10 ⁶ a 23 70 16 14 1320 1.5 × 10 ⁶ 4.5 × 10 ⁶ a 24 70 13 17 17 1320 9.6 × 10 ⁶ 3.8 × 10 ⁶ a 25 70 10 20 1320 Not applicable 26 75 21.9 0.1 0.1 1360 7.6 × 10 ⁷ 1.8 × 10 ⁶ a 27 75 21.8 0.2 1360 8.7 × 10 ⁷ 1.4 × 10 ⁶ a 28 75 75 2 3 1360 9.0 × 10 ⁷ 2.6 × 10 ⁶ b 29 75 20 5 1360 4.3 × 10 ⁷ 3.1 × 10 ⁶ b 30 75 75 178 1360 1.2 x 10 ⁷ 2.8 x 10 ⁶ b 31 75 14 11 1320 8.9 x 10 ⁶ 4.2 × 10 ⁶ a 32 75 75 11 14 1320 1.0 × 10 ⁴ 5.3 × 10 ⁶ a 33 75 8 17 1320 Not applicable 34 80 17 3 1360 8.7 × 10 ⁵ 9.5 × 10 ⁵ b 35 80 15 15 5 1360 3.3 × 10 ⁵ 2.8 × 10 ⁶ b

As is clear from the results shown in Table 1, the semiconductor porcelain composition for a secondary electron multiplying device according to the present invention has a resistance value which is flat or positive with respect to temperature change over a wide range. This makes it possible to manufacture stable secondary electron multipliers that exhibit high gain and have a wide dynamic range and stable operation in a high vacuum.

In the above examples, oxides were used as the raw materials, but if they become oxides by firing, inorganic compounds such as carbonates, hydroxides, nitrates, chlorides, carboxylates, You may use organic compounds, such as an alkoxide. Further, nickel oxide is not necessarily added to the raw material powder, and a semiconductor compound having a predetermined shape obtained by firing a mixed powder of zinc oxide and titanium oxide is dipped with a solution of a nickel compound to be nickel oxide by heat treatment. It may be impregnated by the above means and then heat treated.

Further, as the structure of the secondary electron multiplier,
The structure is not limited to the cylindrical shape shown in FIG. 1, and the structure shown in FIGS.

In the secondary electron multiplying device shown in FIG. 2, two flat plate-shaped semiconductor ceramics 20 having electrodes 21 and 22 formed at both ends are arranged in parallel to form a continuous passage 23. The outer surface of the flat plate 20 may be insulated, but the inner surface is wholly or partially exposed from one end to the other end of the flat plate 20. It should be noted that a plurality of electrodes may be formed not only at both ends of the flat plate but also at required places in the middle of the flat plate 20, if necessary.
Thereby, the multiplication efficiency can be further improved.

The secondary electron multiplying apparatus shown in FIG. 3 is formed by bundling a plurality of unit cylinders 30 each having a semiconductor porcelain having a secondary electron multiplying ability formed in a cylindrical shape and electrodes 31 and 32 formed at both ends. Is. In this case, since the entire cylinder 30 is made of a semiconductor porcelain having a secondary electron multiplying ability, both the inner surface and the outer surface of the cylinder 30 have a secondary electron multiplying ability, and the continuous passage 33 of the cylinder 30 has Not only the inner surface but also the gap 34 formed between the adjacent cylinders 30 can be used as the secondary electron multiplication surface.

The secondary electron multiplying device shown in FIG. 4 comprises a plurality of triangular prism-shaped hollow bodies 40 made of semiconductor porcelain, which are bundled in a pyramid shape, and electrodes 41 and 42 are formed at both ends thereof. According to this structure, as in the case of FIG. 3, not only the inner surface of the continuous passage 43 of the triangular columnar hollow body 40 but also the gap 44 generated between the adjacent hollow bodies 40 is increased in the secondary electron. Available as double side.

The secondary electron multiplying apparatus shown in FIG. 5 is constructed by twisting a plurality of cylindrical semiconductor porcelains 50, and electrodes 51 and 52 are formed at both ends. The secondary electron multiplier made up of the cylindrical semiconductor porcelain 50 has an antipolar particle (for example, cations for incoming electrons with respect to incoming electrons) from the collector side as compared with the linear secondary electron multiplier 1 shown in FIG. 2) can be suppressed, the effective length of the continuous passage 53 can be made longer than the apparent length, the operation can be further stabilized, and the secondary electron multiplication gain can be increased.

The secondary electron multiplying device shown in FIG. 6 is a bundle of a large number of cylindrical semiconductor porcelains 60 having an outer diameter of an octagonal cross section, and electrodes 61 and 62 are formed at both ends. On the outer surface of the cylindrical semiconductor porcelain 60, grooves each having an octagonal side in the axial direction and having a cross section of 1/4 circle are formed. Therefore, not only the continuous passage 63 of the cylindrical semiconductor porcelain 60 but also the cylindrical gap 64 generated between the adjacent cylindrical semiconductor porcelains 60 can be used as the secondary electron multiplying surface, and moreover, the cross section is uniform. Therefore, it is particularly suitable for applications such as image intensifier tubes that require the uniformity and regularity of picture elements.

The secondary electron multiplying device shown in FIG. 7 has a continuous passage 73, and a cylindrical semiconductor ceramic 70 having an outer diameter of hexagonal cross section.
Are bundled together, and electrodes 71 and 72 are formed at both ends thereof so that a gap is eliminated between adjacent cylindrical semiconductor ceramics 70.

The various examples shown in FIG. 6 and FIG.
If necessary, it may be twisted as shown in FIG.

In the secondary electron multiplying device shown in FIG. 8, a plate-like or rectangular parallelepiped semiconductor porcelain 80 having electrodes 81 and 82 formed at both ends is provided with a plurality of continuous passages 8 perpendicular to the electrodes 81 and 82.
3 is formed.

[0026]

According to the present invention, a semiconductor porcelain composition for a secondary electron multiplier having a large secondary electron emission coefficient, a high resistance and a flat or positive temperature characteristic can be obtained. Even if it is reduced to 1/10 or more of that, thermal runaway does not occur, and since it operates in a high vacuum for a long time, it is possible to obtain a linear retainer that is one digit or more wider than the conventional one, and the application range is significantly widened. Further, it becomes possible to operate in a high temperature atmosphere of 100 to 200 ° C., which was difficult in the past. In addition, since the element resistance can be greatly reduced, the amount of heat generated by the element increases, and as a result, the element temperature rises, making it difficult for the gasified sample to be adsorbed to the element surface, and as a result, keeping the element surface clean. Since it drips, there is an advantage that the life is longer than before.

[Brief description of drawings]

FIG. 1 is an experimental circuit diagram for measuring a secondary electron multiplication gain.

FIG. 2 is a perspective view showing an example of the structure of a secondary electron multiplying device using a semiconductor ceramic according to the present invention.

FIG. 3 is a perspective view showing another example of the structure of the secondary electron multiplying device using the semiconductor porcelain according to the present invention.

FIG. 4 is a perspective view showing another example of the structure of the secondary electron multiplying device using the semiconductor porcelain according to the present invention.

FIG. 5 is a perspective view showing another example of the structure of the secondary electron multiplying device using the semiconductor porcelain according to the present invention.

FIG. 6 is a perspective view showing another example of the structure of the secondary electron multiplying device using the semiconductor porcelain according to the present invention.

FIG. 7 is a perspective view showing another example of the structure of the secondary electron multiplying device using the semiconductor porcelain according to the present invention.

FIG. 8 is a perspective view showing another example of the structure of the secondary electron multiplying device using the semiconductor porcelain according to the present invention.

FIG. 9 is a diagram showing a change in resistance value with respect to a change in temperature as a function of temperature.

[Explanation of symbols]

1, 30, 40, 50, 60, 70: Cylindrical semiconductor porcelain,
20, 80: Flat semiconductor porcelain.

[Procedure amendment]

[Submission date] July 8, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

[Means for Solving the Problems] As a means for solving the above problems, the present invention comprises adding a predetermined amount of nickel oxide to a main component composed of zinc oxide and titanium oxide to obtain zinc oxide in an amount of 55 to 80 mol% and oxidized. Composition consisting of 12 to 30 mol% titanium and 0.2 to 20 mol% nickel oxide, preferably 60 to 70 mol% zinc oxide, 20 to 29 titanium oxide.
The composition is made up of mol% and nickel oxide 5 to 20 mol%.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

[0014]

[Table 1] Main component (mol%) Firing temperature Resistivity Gain characteristics No. ZnO TiO ₂ NiO ℃ (Ω ・ cm) at 3KV Curve 1 74 26 0 1380 2.8 × 10 ⁵ 2.0 × 10 ⁶ c 2 55 31 14 1330 ∞ 3 55 28 17 1330 6.3 × 10 ⁸ 2.5 × 10 ⁸ a 4 55 25 20 20 1320 3.8 × 10 ⁸ 3.3 × 10 ⁶ a 5 60 32 32 8 1360 ∞ 6 60 29 11 11 1360 1.5 × 10 ⁹ 2.1 × 10 ⁶ a 7 60 26 14 14 1320 7.7 x 10 ⁸ 2.8 x 10 ⁶ a 8 60 60 23 17 1320 3.4 x 10 ⁸ 3.1 x 10 ⁶ a 9 60 20 20 1320 9.2 x 10 ⁷ 3.0 x 10 ⁶ a 10 60 17 17 23 1300 4.6 x 10 ⁷ 3.2 x 10 ⁶ c 11 65 32 3 1360 ∞ 12 12 65 30 5 1360 1.1 × 10 ⁹ 1.5 × 10 ⁶ b 13 65 27 27 8 1360 8.7 × 10 ⁸ 2.4 × 10 ⁶ b 14 65 24 11 1360 1.3 × 10 ⁸ 3.2 × 10 ⁶ a 15 65 21 14 1320 2.4 x 10 ⁷ 2.8 x 10 ⁶ a 16 65 18 17 1320 6.7 x 10 ⁶ 2.4 x 10 ⁶ a 17 65 15 20 1320 4.0 x 10 ⁵ 3.6 x 10 ⁶ a 18 65 12 12 23 1300 3.8 x 10 ⁴ 3.2 x 10 ⁶ c 19 70 27 273 1360 3.6 x 10 ⁴ 1.0 × 10 ⁶ b 20 70 25 5 1360 8.7 × 10 ⁷ 2.1 × 10 ⁶ b 21 70 22 22 1360 2.5 × 10 ⁷ 3.0 × 10 ⁶ b 22 70 19 19 11 1320 8.9 × 10 ⁶ 3.2 × 10 ⁶ a 23 70 16 14 1320 1.5 × 10 ⁶ 4.5 × 10 ⁶ a 24 70 13 13 17 1320 9.6 × 10 ⁶ 3.8 × 10 ⁶ a 25 70 10 20 1320 Not applicable 26 75 21.9 0.1 0.1 1360 7.6 × 10 ⁷ 1.8 × 10 ⁶ c 27 75 21.8 0.2 1360 8.7 × 10 ⁷ 1.4 × 10 ⁶ a 28 75 75 2 3 1360 9.0 × 10 ⁷ 2.6 × 10 ⁶ b 29 75 20 5 1360 4.3 × 10 ⁷ 3.1 × 10 ⁶ b 30 75 75 178 1360 1.2 x 10 ⁷ 2.8 x 10 ⁶ b 31 75 14 11 1320 8.9 x 10 ⁶ 4.2 × 10 ⁶ a 32 75 75 11 14 1320 1.0 × 10 ⁴ 5.3 × 10 ⁶ a 33 75 8 17 1320 Not applicable 34 80 17 3 1360 8.7 × 10 ⁵ 9.5 × 10 ⁵ b 35 80 15 15 5 1360 3.3 × 10 ⁵ 2.8 × 10 ⁶ b

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

In the above examples, oxides were used as the raw materials, but if they become oxides by firing, inorganic compounds such as carbonates, hydroxides, nitrates, chlorides, carboxylates, You may use organic compounds, such as an alkoxide. Further, nickel oxide is not necessarily added to the raw material powder, a mixed powder of zinc oxide and titanium oxide is molded into a predetermined shape, then calcined, and the calcined product is a solution of a nickel compound that becomes nickel oxide by heat treatment. Alternatively, the calcined product may be impregnated with the nickel compound by immersing in or by other means, and then calcined.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasunobu Yoneda 2-26-10 Tenjin, Nagaokakyo City, Kyoto Prefecture Murata Manufacturing Co., Ltd.

Claims (1)

[Claims] 1. A semiconductor porcelain composition for a secondary electron multiplier, comprising 55-80 mol% zinc oxide, 12-30 mol% titanium oxide, and 0.2-20 mol% nickel oxide.