JPS6084735A - Secondary electron multiplying material - Google Patents

Abstract

PURPOSE:To obtain a secondary electron multiplying material having the moderate volume resistivity and the enhanced counting rate's dependency of multiplier gain, by adding a particle-dispersive conductive agent into a high molecular composition which contains a molecule-dispersive conductive agent in the matrix. CONSTITUTION:A molecule-dispersive conductive agent such as the salts of 7,7, 8,8-tetracyanoquino-dimethane or the like is made to be contained in a macromolecule whose secondary electron emission ratio is great like polyvinyl chloride or the like, thus a high molecular composition whose volume resistivity is 10<8>-10<11>OMEGA.cm can be obtained. Further, a particle-dispersive conductive agent such as carbon black or the like is added into said composition and kneaded well in order to obtain the captioned secondary electron multiplying high molecular material. This material has excellent molding processability, good heat resistance and also small temperature coefficient of resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a channel-type secondary electron multiplier made of a polymer material and a polymer material for secondary electron multiplication used for the multiplication surface.

Conventionally, channel type secondary electron multiplier (hereinafter abbreviated as OEM)
is made of high-lead glass, ceramic, etc., and replaces the traditional split dynode type multiplier tube with charged particles, photons,
Widely used for detecting X-rays, etc. In this OEM, the inner wall of the tube is composed of a layer that has the ability to emit secondary electrons and has an appropriate resistance value, and the secondary electrons emitted from the inner wall of the tube are accelerated by a high electric field. The electrons are multiplied by repeating the second electron emission. For OEM, only the inner wall of the tube is semiconductive and has secondary electron emission ability, and the surface shape is made of high lead glass, and the entire tube has moderate semiconductivity and secondary electron emission ability. Two types of bulk types are commercially available, made of materials such as ceramics such as Zn T zO3 and B aT x Os. As a practical configuration, O
There are two types of EM, one with a linear structure and one with an arcuate structure.The linear structure is susceptible to the effect of ionization of residual gas in vacuum, which is called an ion feed bank, and in some respects it is not practical. Often difficult to use.

For this reason, arcuate structures are often used, but this causes difficulty in OEM manufacturing. Also, for OEM, it is small, lightweight, and has high gain.

It has an excellent feature of low noise and exhibits this feature when used in pulse count mode, but it is expensive and made of fragile materials such as glass and ceramics, and has structural limitations that make it prone to breakage. It has the disadvantage of being easy to do.

Therefore, in order to eliminate this drawback, CEM (hereinafter referred to as FCEM) has been produced by applying the secondary electron emission function of organic polymers and taking advantage of the excellent moldability and flexibility of polymer materials. This FOEM is a bulk-type flexible CEM made by molding a semiconducting polymer composition into a tube shape, and it can be bent into an arc of arbitrary curvature to prevent the effects of ion feedback. Can be used with gain.

In addition, it is strong against mechanical shocks and acceleration shocks and is resistant to damage, so it is suitable for use as a detector of charged particles and photons in outer space when mounted on rockets and artificial satellites. demonstrate.

The material used for this OFcEM K is 105-1010Q-
It is an electronically conductive polymer composition with a moderate resistivity of cm, and its maximum secondary electron emission ratio δtnax is:
It is known that aliphatic polymers are larger than aromatic polymers, and polymers with a large solid-state ionization potential exhibit a large value, and that the δma occurs at a low primary electron energy (Epmax) of 200 to 300 eV. . Therefore, Epm&! For low-energy primary electrons below, δ has a relatively large value. Therefore, when an organic polymer is applied as a secondary electron multiplier, the electrons that collide with the inner wall of the multiplier under a constant acceleration voltage will have a large number of collisions n and a relatively large δ value. In order to obtain a large gain as expressed by gain G=δ0, a large gain of 108 was easily obtained with an applied voltage of skV. And, as an electron conductive polymer composition used in a multiplier tube, a particle-dispersed polymer composition is prepared by dispersing carbon black, graphite, metal, etc. in particulate form in an insulating polymer with a high secondary electron emission ratio. and (B) a molecularly dispersed polymer composition in which an organic semiconductor is molecularly dispersed (dissolved) in an insulating polymer with a high secondary electron emission ratio, and (a polymeric organic semiconductor in which the q polymer itself has conductivity). There was.And these (B) fcl were
Both of them can be used as secondary electron multipliers at 1
However, this time, we found that there is a large difference in the dependence of the gain on the counting rate. In other words, in the multiplier tube (5), the dependence of the gain on the counting rate is poor, and as the counting rate increases, the gain decreases and the output current saturates at a counting rate that is much lower than the theoretical limit. It's here. On the other hand, (B) (C10 multiplier shows excellent count rate dependence close to the Habo principle limit,
Even at high counting rates, the gain did not decrease and a large output current was obtained. However, (B), (C1
The material has a specific resistance value of 105 to 1010Ω・
There are few materials that have a volume resistivity value of ω, and there are many materials that are extremely lacking in formability or that deteriorate quickly due to heat and release a large amount of decomposition gas, so there are very few materials that can be easily processed in practical terms. Ta.

In view of this point, the present invention has a suitable volume resistivity value of 105 to 1010Ω・α by combining 8 and (B) or 0, and has excellent counting rate dependence of the multiplier gain. It is highly moldable and has good heat resistance.
The present invention also provides a polymer composition for secondary electron multiplication that has a small temperature coefficient of resistance and is useful in practice.

Explain clearly.

4. Particle-dispersed conductive polymer composition.

The secondary electron emission ratio δ of a polymer is larger as the polymer has a higher solid-state ionization potential, and this tendency is consistent with the fact that δ is larger in aliphatic polymers than in aromatic polymers. Contrary to the properties of organic semiconductors, insulating polymers tend to have large δ values. Therefore, it is extremely easy to select a material with a large secondary electron emission ratio and excellent moldability among insulating polymers, and the insulating polymer selected in this way is used as a matrix polymer. By dispersing and kneading a particle-dispersible conductive agent such as carbon, graphite, metal, or metal oxide, a composition having a volume resistivity of 10 5 to 10 Ω can be obtained. The particle-dispersible conductive agent referred to here means that it has no solubility in the polymer matrix,
A conductive agent that is dispersed in granular form, and carbon blanks and metal powders such as graphite, silver, and nickel are often used for polymers. When a particle-dispersible conductive agent is kneaded into a polymer in this way, the electrical resistance is determined by the number of contacts between the conductive particles, as shown in the model shown in Figure 1, and the electrons are distributed between the conductive particles in the polymer matrix. Flowing through channels. In FIG. 1, 1 is a matrix polymer, 2 is an electrode, 3 is a particle-dispersed conductive agent,
4 is a DC power supply, and 5 is a secondary electron near the surface of the polymer.

As an example of such a particle-dispersed conductive polymer composition,
Polyvinyl chloride (abbreviated as PVC) and polyurethane (PU
A semiconductive composition obtained by adding carbon black (average particle size: 400 mm) to a matrix polymer was formed into a tubular shape (inner diameter: 1.2, body outer diameter: 3,6 mm).
The secondary electron multiplier tube is molded to a length of 11 crn mm.
The dependence of the gain on the counting rate is shown in the figure.

This multiplier tube has a resistance value of 108Ω (volume specific resistance ρ of 106
Ω・crn), a gain of 1o8 is obtained, but
As the counting rate increases, the gain decreases greatly, and its output current ratio! . /Id (IO: output current, d: tube current) does not reach the principle limit of 10-1 and is saturated at 10-2 to 10-5. When other particulate conductive agents or polymers are used, the dependence of the gain on the count rate is poor, and the output current ratio I
Many of them are saturated when o/Id is around 10-5. Among these materials, carbon black with a small average particle size was selected as the particulate conductive agent, and the best characteristics were obtained by considering the composition of the composition and the orientation of the conductive agent in the particle dispersion system depending on the molding method. It has been found that a multiplier tube which has the characteristics shown above in the west of FIG. 2 and which can obtain a large output current closer to the principle limit cannot be obtained with this particle-dispersed polymer composition.

On the other hand, when the temperature dependence of the resistance value of this particle-dispersed polymer composition is measured, it has a small positive temperature coefficient, as shown in the multiplier tube shown in Figure 3. It has an advantageous side.

(Tsukasa Molecularly dispersed conductive polymer composition.

As the matrix, a material having a large secondary electron emission ratio and excellent moldability is selected, similar to the matrix polymer of the above formula. The conductive agent used here is an organic semiconductor that has molecular dispersibility (solubility) in the matrix polymer, and the matrix polymer and the conductive agent are selected accordingly. Charge transfer complexes are suitable as organic semiconductors with high electrical conductivity and molecular dispersibility in polymers, and ionic radical salts are the most common. Among them, 7゜7
．． 8.8-tetracyanoquinodimethane (hereinafter referred to as TCNQ)
A molecularly dispersed conductive polymer composition is constructed by dissolving and dispersing an ion radical salt having an electron acceptor such as P-chloranyl or p-chloranil as an electron acceptor into a polar polymer or an electron-donating polymer. Among these molecularly dispersible conductive agents, TCNQ salt has high conductivity and is one of the most stable, but most TCNQ salts that use nitrogen-containing molecules (such as amines) as electron donors Most of them have a melting point of 9 decomposition points below 150'C, and cannot be mixed with polymers at temperatures above 150'C, which is the molding temperature of polymers, due to decomposition and deterioration. This TCNQ salt is the most thermally stable, with 20
Those that can withstand processing temperatures up to 0°C are metal TCs that use metals (especially alkali metals) as electron donors, as shown in Figure 4.
It is NQ salt. However, the drawback of these metal TCNQ salts is that they have a high volume resistivity (ρ-1o3 to 1o6Ω·crn). - As an example, among the metal TCNQ salts, Na T
A volume resistivity of 1010Ω was obtained by kneading CNQ (p-10”Ω-crn) powder as a molecularly dispersible conductive agent into a composition of polyvinyl chloride (PVC) and polyurethane (PU).
・. This paper describes the characteristics of a secondary electron multiplier made from a molecularly dispersed polymer composition. This P V C+ P U 1N
The composition consisting of a T CN'Q has a high specific resistance value (ρ-1o
5 Ω・Cm), it is difficult to create a polymer composition with a specific resistance value of 10 Ω・cm or less without impairing the molding processability of the composition (in general, adding additives of 40 volume coefficient or more will reduce processability). is significantly attenuated). The gain of a multiplier tube using this composition is as large as 108, and the dependence of the gain on the counting rate is shown in FIG. 2(E). Here, the output current ratio Io
The reason why the gain decreases at a low count rate even though /Id has reached the principle limit of 10 is because the resistance value of the multiplier tube is as high as 1012 (ρ-1010Ω・-). So, the resistance value is 1012Ω (ρ=1o10Ω・6n
) → 108 to 9Ω (ρ = 106 to 7Ω·α), which is a drawback. The temperature coefficient of resistance of the multiplier tube has a large negative coefficient as shown in FIG. 3(B), which is a major drawback in the use of the multiplier tube. As described above, it was found that the multiplier tube made of a molecularly dispersed polymer composition, although its basic multiplication characteristics were good, did not satisfy the following conditions, namely, the specific resistance value was 106 to 9Ω - The lack of a material that has an optimal value for m, has good moldability, excellent thermal stability, and a small temperature coefficient of resistance has been the cause of great difficulty in actually manufacturing multiplier tubes.

The present invention is directed to these eight different dispersion states of the conductive agent.

By combining the two of (T3), eliminating all the drawbacks of each of the above ^) and (E), we can create an excellent secondary electron increaser with a new synergistic effect, rather than just a combination of (A) and (B). We succeeded in obtaining double material. In other words, the reason why the maximum output current is small and the gain is low in the case of the particle-dispersed composition shown on the west is that the resistance value of the multiplier tube is 1o8Ω (ρ
-1o6Ω・crn), the conductive agent does not dissolve in the polymer, so the resistance value of the polymer matrix does not decrease, and the positive charge on the surface when secondary electrons 5 are emitted as shown in Figure 1. This is because the conductive agent cannot easily supply electrons to neutralize the Therefore, we added a molecularly dispersible conductive agent to the matrix polymer to increase the volume resistivity to 1o11Ω, c
rn or less, and a particle-dispersible conductive agent is further added thereto to obtain a semiconductive polymer composition having a volume resistivity of 10 Ω·α, which is the optimum resistance value for a secondary electron multiplier. By doing this, the resistance value of the polymer matrix is reduced to a region where electron movement is easy below 1Q11Ω・m, so that the resistance value of the polymer matrix is reduced to a region where electron movement is easy. This makes it easy to supply electrons from the conductive channels to the surface where the secondary electrons were emitted, making it an excellent electron multiplier material. The volume resistivity value ρ of the polymer composition containing only the molecularly dispersible conductive agent is (1), 1
The present invention does not have a significant effect when it is equal to or larger than o Ω·α. (2) When the resistance is in the range of 108 to 1011 Ω, the great effect of the present invention is exhibited by further adding a particle-dispersible conductive agent to form a composition of 1Q5 to 109 Ω. (3)
It was found that when the resistance was 10 8 Ω·(7) or less, there was almost no need to further add a particle-dispersible conductive agent.

The composition according to the present invention has an appropriate electrical resistance value and excellent secondary electron multiplication properties. Furthermore, if the amount of these conductive agents is within 40% by volume relative to the matrix polymer, the mechanical processability of the polymer will not deteriorate. Therefore, since a composition can be manufactured within the range of the amount of the conductive agent of the present invention, it has excellent moldability like a general-purpose polymer, which is a great industrial advantage.

In addition, the present invention provides that even if the molecular dispersion conductive agent has a slightly high specific resistance value, it can be used satisfactorily as long as it gives the composition a specific resistance value of 10 Ω・α or less, and is conductive. The range of agent selection has been expanded, and excellent secondary electron multiplier materials can be created using conductive agents with high heat resistance and stability.

Further, a major advantage is that there is little variation in resistance due to molding operations, and in addition to this resistance stability, the temperature coefficient of resistance is small. The resistance value of a particle-dispersed conductive composition generally exhibits the behavior shown in Figure 5 depending on the amount of conductive agent added, and the resistance value of a semiconductive composition made of 105 to 1010Ω/steel varies greatly, depending on the forming processing conditions. 1-2
It is a well-known fact that resistance values that differ by orders of magnitude can be produced, and this is particularly noticeable in chain-shaped conductive agents such as carbon plaque. On the other hand, a molecularly dispersed composition exhibits a stable resistivity value regardless of shape or molding processing conditions.

In a composition in which both of these dispersion systems of the present invention are appropriately used in combination, the resistance value has small variations and the temperature coefficient of resistance has a small negative coefficient. For example, in the composition of Example 1 shown later, the temperature coefficient of resistance is small as shown in Figure 3 (q), and the composition has resistance stability as shown in (B) but has a large negative temperature coefficient. This is because the conduction mechanism of a molecular dispersion system with a large resistance temperature coefficient like CB) is relaxed by the conduction mechanism of a particle dispersion system with a small positive temperature coefficient like Nishi, and the present invention's (q The results show that the present invention has a small negative temperature coefficient of resistance.Thus, the present invention is of great value as it provides an excellent secondary electron multiplier material.

Next, regarding the specific materials used in the present invention,
As a molecularly dispersed conductive agent, a charge transfer complex type organic semiconductor such as tetracyanoethylene is preferred.

There are charge transfer complexes that use TCNQ, p-chloranil, trinitrobenzene, etc. as electron acceptors and amines, aniline derivatives, tetrathiofulvalene, phenothiazines, onium cations, metals, etc. as electron donors. When these molecularly dispersible conductive agents are mixed into a matrix polymer and subjected to heat processing such as roll kneading or extrusion molding, materials with excellent heat resistance and low decomposition gas release should be selected. Metallic TCNQ salts are stable.

Among them, NaTCNQ and KTCNQ are the most stable.

On the other hand, when dissolving a matrix polymer in a solvent to form a paint film for secondary electron multiplication, there is no need to worry about the heat resistance as described above, and charge transfer complexes with low vapor pressure are used. You just have to choose, and it's easy to choose.

The matrix polymer that molecularly disperses this molecularly dispersible conductive agent (charge transfer complex) is a polar polymer and has a large secondary electron emission ratio, such as PVC, PU, polyvinyl fluoride, and silicone resin.

Vinyl acetate, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, polystyrene, polyester, polyacetal, polyamide, phenol resin, epoxy 7 resin, melamine resin, etc., copolymers or kneaded products of these polymers, or polar Polymer compositions containing plasticizers and the like also belong to this category. moreover,
Electron-donating polymers have even greater solubility in charge transfer complexes, such as polyamide, polyurethane, polyvinylpyridine, polycation, polyvinylpyrodrine, polyacrylamide, polyvinylcarbazole, or copolymers and kneaded products thereof. Yes, it is suitable as a matrix polymer. Furthermore, in order to improve thermal stability and moldability, stabilizers commonly used in polymers may naturally be mixed into these compositions.

Since this molecularly dispersible conductive agent has solubility (compatibility) with the matrix polymer, it is not necessary that all of the added conductive agent be dissolved, and the polymer composition in which the conductive agent is dissolved is 10 Ω・m. It suffices if it has the following volume resistivity.

Carbon black and graphite are common as particle-dispersible conductive agents added to this composition of 10 Ω・α or less in which conductive agents are molecularly dispersed, and metal particles are also good, among which N i and Ag are stable. There is.

Carbon black not only serves as a conductive agent when mixed with polymers, but also serves as a mechanical reinforcement for polymer compositions, which has the advantage of increasing moldability and greatly improving the strength of molded products. . "Particles J" here refers to particles with a particle size of several tens of millimicrons to several tens of microns, which have no solubility in the polymer matrix and are dispersed in a granular form, and the particle size is fine. Needless to say, it is better from the viewpoint of uniformity of the composition and molding process.

Next, examples of the present invention will be described.

Example 1 15fi' of carbon black was further added to a composition of volume resistivity ρ2σc=2×10100・α, which was obtained by adding Na T CNQ 25 f to composition 607 of polyvinyl chloride (PVC) and polyurethane (PU). 170°C
A composition was obtained by kneading with a heated roll. This has an inner diameter of 1.
2 mm 1 outer diameter 3.6 mm, length 11 crn tube shape (
The opening was formed to have a diameter of 1 crn and a length of 1.6 cm to obtain a multiplier tube. The resistance value was 109Ω, and the dependence of the gain on the count rate showed excellent characteristics as shown in Figure 2 <Q.
With an applied voltage of V, the gain is 1o8, and the maximum output current ratio is ■. /■
It has almost reached the principle limit of d-0.3.

For this reason, this multiplier tube has a power of 104 to 5 CPS (count 7
It can be used with a high gain of 10" up to a high count rate of 10" (PVC-I-PU).
It was found that the excellent dependence of the gain on the count rate was shown in the ranges of 0%, 40-12% for NaTCNQ, and 10-18% for carbon black.

Example 2 KTCNQ3 (1, carbon black 177) was added to polyurethane 6og, kneaded, and then molded into the same shape as in Example 1 using an extruder.The resistance value showed 4 x 1oΩ, and 3k
With an applied voltage of V, the gain is 2XIQ'' and the maximum power current ratio is 2XIQ.

/Id=0.3, and the maximum output current was 4.6 μA.

Example 3 Composition 10P of Example 2 was dissolved and dispersed in tetrahydrofuran 40F to prepare a paint. This paint was applied to the inner surface of a circular arc tubular glass tube with an inner diameter of 2 mm, an outer diameter of 3.5 mm, and a length of 10 Cfn, and after drying with hot air, the electrodes were removed with silver paint to prepare a multiplier tube. The resistance value was 3×10Ω. The gain of the multiplier tube with the applied voltage 3. 1.6X at OkV
10, the maximum output current ratio. /Id indicated o, 33, and the maximum output current IO was 3.3×10 A.

Furthermore, in addition to the composition [Matrix polymeric decile-dispersed conductive agent 10-particle dispersible conductive agent] described above, the present invention also provides a composition called [Polymer organic semiconductor particle dispersible conductive agent]. is also possible. A polymeric organic semiconductor is one in which the polymer itself has electrical conductivity.
J-Fuchs molecular conductive agent molecules dispersed in molecular form are bonded to the main chain or branches of a polymer matrix through chemical bonds to form conductive portions in the polymer chains. Therefore, it can be seen that all the above-mentioned ideas also hold true in this composition of [polymeric organic semiconductor particle dispersed conductive agent]. This is because the electronic conductivity of organic compounds is entirely based on the formation of conductive channels between conjugated π-electron structure moieties. However, since this polymeric organic semiconductor contains a π-electron-based conductive moiety in the polymer chain, the polymerization conditions for this polymer are difficult in actual industrial use, and the machinability (formability) of the resulting polymer is difficult. Its thermal stability is also extremely inferior to that of general-purpose polymers, making it difficult to put it into practical use. However, the principle of the present invention also holds true in this system of [polymeric organic semiconductor particle dispersed conductive agent], and while waiting for the appearance of excellent polymeric organic semiconductors in the future, it is possible to carry out a few prototype experiments. Next, examples regarding these will be shown.

Example 4 Part of poly-2-vinylpyridine/vinyl acetate copolymer was complexed with TCNQ to give a volume resistivity of 1010Ω.
of polymeric organic semiconductor powder 8.61 and carbon black 1
．． 62 was added thereto, 4.0% of dimethylformamide was dissolved therein, and the mixture was dispersed in an attritor (stirring ball mill) for 1 hour to obtain a paint. This paint was applied to the inner surface of the same circular arc tubular glass tube as in Example 3 to obtain a 7×10 8 Ω multiplier tube. The gain is 7×107 with an applied voltage of 3kV.
When the count dependence was measured, a large output of maximum output current ratio I0/Id=0.28 was obtained. The maximum output current at this time is 1.2 μA.

In this way, the present invention provides an extremely excellent composition for a secondary electron multiplier material made of a polymer. The composition of the present invention constitutes a multiplier tube having a large multiplication/gain, and the dependence of the gain on the counting rate is such that the gain does not change up to a high counting rate which is the limit of the principle, and the maximum output current is the same as the tube current. It has reached the limit of tens of coefficients. The composition of the present invention, which has such excellent multiplication properties, has other advantages in industrial manufacturing, such as a wide range of material selection, thermal stability, moldability, small temperature coefficient of resistance, and strong mechanical strength. It has excellent advantages. The multiplication material according to the present invention can be applied to secondary electron multipliers and channel plates in which they are arranged two-dimensionally. Because secondary electron multiplier materials have a high solid-state ionization potential, they emit photoelectrons in response to high-energy electromagnetic waves such as vacuum ultraviolet rays and soft X-rays, and can act as detectors for vacuum ultraviolet rays and soft It can also be used as a highly sensitive charged particle detector. It can also be used as a photomultiplier tube in combination with a photocathode.

In addition, channel plates with tubes arranged in a plane and sponge-like porous channel plates can be used for two-dimensional information processing such as image information, and can be used for multi-detector, image pickup tubes, high-speed cathode ray tubes, and X-ray images. It can be applied to many fields such as converters, phototubes, and image intensifiers, and has great industrial value.

[Brief explanation of drawings]

Figure 1 shows a model of conduction and electron emission of a particle-dispersed polymer composition, and Figure 2 shows the counting rate dependence of the gain of a secondary electron multiplier. double tube characteristics,
(B) is the characteristic curve of the multiplier tube made of the molecularly dispersible composition, (q is the characteristic curve of the multiplier tube according to one embodiment of the present invention.
The figure shows the temperature dependence of the resistance value of a multiplier tube, where the west side shows the resistance-temperature characteristics of a multiplier tube made of a particle-dispersed composition, (B) shows the characteristics of a molecular-dispersed composition, and (q is the temperature dependence of the multiplier tube made of a particle-dispersed composition. FIG. 4 is a characteristic curve of a multiplier tube according to an embodiment.
Na T CNQ. 12 of the spin concentration (radical concentration) of each charge transfer complex such as tetramethylamine TCNQ and methylamine TONO.
This is the heat resistance property at 0'C. FIG. 5 is a diagram showing the relationship between the amount of conductive agent added and electrical resistance in a polymer composition containing a particle-dispersed conductive agent. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 1. Prison (sword lint/clothing) Figure 3.

Claims (1)

[Claims] (1) Volume resistivity 108 to 1011 containing a molecularly dispersed conductive agent in a matrix polymer with secondary electron multiplication effect
9. A secondary electron multiplier material characterized in that a particle-dispersible conductive agent is added to the polymer composition of item 9. (2) The secondary electron increaser according to claim 1, wherein the polymer composition is formed by kneading a molecularly dispersible conductive agent made of a charge transfer type organic semiconductor into the matrix polymer. Double material. (3) The secondary electron multiplier material according to claim 2, wherein the molecularly dispersible conductive agent is a salt of 7,7,8,8-tetracyanoquinodimethane. (4) The secondary electron multiplier material according to claim 3, wherein the salt of 7,7,8,8-tetracyanoquinodimethane is a salt with a metal cation. (+5) The secondary electron multiplier material according to claim 4, wherein the metal cation is a sodium ion or a potassium ion. (6) The secondary electron multiplier material according to claim 2, wherein the matrix polymer is an electron-donating polymer composition. (7) The electron-donating polymer composition has urethane bonds (
-NHCOO-), the secondary electron multiplier material according to claim 6, wherein the secondary electron multiplier material is a composition containing -NHCOO-). (8) The molecularly dispersible conductive agent is formed by chemically bonding an organic electronically conductive conductive agent to the main chain or branch of a matrix polymer.
The secondary electron multiplier material described in section. (9) The secondary electron multiplier material according to claim 8, wherein the organic electron conductive conductive agent contains 7.7.8.8-tetracyanoquinodimethane. (10) The secondary electron multiplier material according to claim 1, wherein the particle-dispersible conductive agent is carbon black or graphite.