JPS607053A - Secondary electron multiplying device - Google Patents

Abstract

PURPOSE:To reduce ion feedback and noise by installing an accelerating electrode on this side of the output terminal of a cylindrical secondary electron multiplier having an inner wall surface made of a secondary-electron-discharging semiconductive material and fixing a collector electrode on the end surface of the output terminal. CONSTITUTION:A secondary electron multiplier 11 is made by forming a semiconductive material having a secondary-electron-discharging ability into a cylindrical shape which is then curved into spiral form. A cone-like input electrode 12 is attached to the input terminal 11a of the multiplier 11. An accelerating electrode 13 to which acceleration voltage (EL) is applied is wound around a position which is located on this side of the output terminal 11b of the multiplier 11 and apart from it by a distance (d) of about 5mm.. Next, a collector electrode 14 is fixed to the end surface of the output terminal 11b. After that, a load resistance (RL) is connected between the electrode 14 and an earth, and voltage delivered from the resistance (RL) is amplified with a pre-amplifier 5. Owing to the above constitution, the generation of ion feedback and noise can be reduced, the structure can be simplified and the acceleration voltage can be decreased. A member provided between the electrodes 13 and 14 may consist of an insulating cylinder.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a secondary electron multiplier, and more particularly, the present invention relates to a secondary electron multiplier, and more particularly, to a cylindrical secondary The present invention relates to a secondary electron multiplier that detects secondary electrons output from an electron multiplier to detect ions and electrons in space.

(Conventional technology) Generally, the second order multiplier is a photomultiplier.

In the laser, it is used to multiply the photoelectron flow by utilizing secondary electron emission at a secondary electron emission surface called a dynode, but this type of secondary electron multiplier has a complicated structure and a large shape. It was also a big deal.

For this reason, in recent years, semiconductor materials with secondary electron emitting ability have been used in devices that detect ions and electrons in outer space, and in mass spectrometers that analyze the mass of class 2 ions and atoms. Using a secondary electron multiplier formed in
This is a so-called channel electron multiplier that can be used by directly attaching it to equipment that detects ions or electrons.

Conventionally, this type of secondary electron multiplier has been used to detect ions and electrons using a direct current method, as shown in Figure 1.
Q, 5 mm to 1.5 mm from the output end of the secondary electron multiplier tube 2, which is made of a cylindrical semiconductor material having secondary electron emission ability and has a cone-shaped input voltage j1 attached to the input side. Qm
A collector 3 made of a circular metal plate is arranged with a gear rough 'g of m, and a collector 3 made of a circular metal plate is placed on the input electrode 1 at a distance of 13 to ground.
KVr,j, -4KVO high voltage E11 is applied, while accelerating voltage EL of -100V rl to -200V with respect to ground is applied to the accelerating electrode 4 wound around the output terminal, and this accelerating voltage E■, The multiplication current of the above collector 3
I was collecting it.

In addition, when detecting the secondary electron flow output from the output end of the secondary electron multiplier 2 in a pulsed manner, the accelerating electrode 4 in FIG. 1 can be omitted and the collector 3 in close contact with the output end of the secondary electron multiplier tube 2, and in the same manner as in Fig. 1,
A device in which a pulse output is obtained from the preamplifier 5 is generally known.

1 and 2, the output secondary electron current is charged to the t4 floating characteristic C8 generated between the collector 3 and the ground, and the charged electric charge is transferred to the load resistance k.
The voltage generated across the load resistor RI- at this time is generally amplified by a preamplifier 5.

2 in Figure 1, which detects electrons and ions with direct current using
The secondary electron multiplier requires a support member 6 that supports the collector 3 with a gap g relative to the end face of the output end of the secondary electron multiplier 2.

Moreover, there is a problem that secondary electrons jump out from the gap g, causing noise, ion feedback, etc. Therefore, in order to prevent ions from jumping out from the cap g, the surroundings of the gap g are If the secondary electron multiplier is surrounded by a shield plate (not shown), a shield plate and a support member for supporting the shield plate are required, which may complicate the structure near the output end of the secondary electron multiplier.

(Object of the invention) The present invention has been made to solve the above problems, and includes:
The purpose of this is to provide an accelerating electrode in front of the output end of the secondary electron multiplier tube in a secondary rapid electron multiplier having an accelerating electrode, and to fix the collector electrode to the end face of the output end. Seal the output end of the electron multiplier tube with the collector electrode I
The second objective is to reduce ion feedback and noise, and to simplify the structure.

(Structure of the Invention) For this reason, the present invention provides an accelerating electrode in front of the output end of a cylindrical secondary electron multiplier tube whose inner wall surface is made of a semiconductor material having secondary electron emission ability. Additionally, a collector electrode is fixed to the end face of the output end.

(Example) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 3, 11 is a secondary electron multiplier;
The secondary electron multiplier tube 11 is made of a ceramic semiconductor material, for example, zinc titanate, which has a secondary electron emission ability, and is formed into a cylindrical shape, and is curved into a spiral shape to eliminate ion feedback inside. Input end 1 ], H is a cone-shaped input electrode 12.

The dimensions of the secondary electron multiplier tube 11 are, for example, 13Qmm in total length and 3.0Qmm in outer diameter. Omm, the inner diameter is 1.0mm. Further, the opening of the input electrode 12 is 10vtm, and the length is 10++π.

The distance 1illild from the end surface of the output end 11b before the output end 11b of the secondary electron multiplier 11 is d÷5mm.
An accelerating electrode 13 made of a silver (Ag) wire is wound around the position, and an accelerating voltage EL is applied to the accelerating electrode 13.

A collector electrode 14 is bonded to the end surface of the output end 11b of the secondary electron multiplier 11 using epoxy resin. The collector electrode 14 may be bonded to the end surface by baking silver paste, glass frit, or the like.

A negative ni resistance R is connected between the collector electrode 14 and the ground.
L is connected, and the voltage output from this load resistor RL is amplified by a preamplifier 5.

By doing as above, the output end 11 of the secondary electron multiplier tube 11
All the secondary electrons output from b are captured by the collector electrode 14, and it is possible to prevent the secondary electrons from flying out of the secondary electron multiplier 11 and causing ion feedback and noise. The collector electrode 14 is supported by the output end 11b of the secondary electron multiplier tube 11', and a special support member for supporting the collector electrode 14 is not required, and the structure of the secondary electron multiplier can be simplified and simplified.

In the embodiment shown in FIG. 3, the total length of the secondary electron multiplier tube 11 is shortened by about 5 mm, and the end ifo of the output end 11b is
As shown in FIG. 4, a quotient 15 made of an insulating material with a length 6 of approximately 5 mm is glued coaxially with the secondary electron multiplier 11, and a collector voltage f'/m41.4 is attached to one end of the quotient 15 made of an insulating material. may be fixed.

In the above embodiments, the material of the secondary electron multiplier 11 is not limited to zinc titanate-based materials, but may also be barium titanate-based materials or other materials. Although not specifically shown, the secondary electron multiplier may be a so-called thin film type, in which a secondary electron emitting film is formed on the inner surface of lead glass formed in the shape of a lead glass. good.

In addition, the secondary electron multiplier tube 11 may be curved into a wave shape other than a spiral shape, and its cross-sectional shape is not limited to a circular shape.

(Effects of the Invention) As is clear from the detailed description hereinafter, the present invention provides a secondary electron multiplier having an accelerating electrode, in which an accelerating electrode is provided in front of the output end of the secondary electron multiplier. Since the output end of the secondary electron multiplier tube surrounds the space between the accelerating electrode and the collector N pole by providing a shield plate and a shield plate to prevent secondary electrons from jumping out between the accelerating electrode and the collector electrode In addition to eliminating the need for the support stand, the collector N pole is also fixed to the output end of the secondary electron multiplier tube, and the structure of the secondary electron multiplier is also omitted. or 1 large]
Furthermore, the acceleration voltage can be lowered.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams of a conventional secondary electron multiplier, respectively, FIG. 3 is an explanatory diagram of an embodiment of a double-blow electron multiplier according to the present invention, and FIG. FIG. 3 is an enlarged sectional view of a modification of the embodiment. 11...Secondary electron multiplier, 1], a...Input end, 111)...Output end, 13...Acceleration electrode, 1
4... Collector Den] Moe, 15... Tube. Patent Applicant: Murata Manufacturing Co., Ltd. Agent ↑Physicist Aoyama Aoyama Ioka Riki・2 people

Claims (2)

[Claims] (1) An accelerating electrode is provided in front of the output end of a cylindrical secondary electron multiplier tube whose inner wall surface is made of a semiconductor material having secondary electron emission ability, and a collector is provided on the end surface of the output end. A secondary electron multiplier characterized by having fixed electrodes. (2) The secondary electron multiplier according to claim 1, wherein the member between the accelerating electrode and the collector electrode is made of an insulating cylinder.