JPH1092375A - Multiple detector of electron - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform conduction of a high voltage of a single system into a vacuum and provide an optimum operating voltage for respective channel-tron by providing a bias resistance having a variable resistance value corresponding to each channel-tron. SOLUTION: A channel-tron 8 and a resistance R of the channel-tron itself, bias resistances R1 and R2 , and a coupling capacitor C1 constitutes a circuit of a single system channel-tron. In this case, an applied voltage to the channel- tron 8 is determined by a supply voltage HV, the resistance R2 , and the resistance R. By changing a bias resistance R'2 using a variable resistor, even if the voltage HV is constant, a voltage between both ends of the channel-tron can be changed. Consequently, when a mechanism for changing the bias resistance is thus provided for each channel, an operating voltage can be changed every individual channel-tron; therefore, a stray capacitance is reduced, and an operating voltage value can be applied to individual channel-trons with fast response and high wave-peak.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplex electron detection device having a plurality of channeltrons for detecting electrons by applying a high voltage in a vacuum through a bias resistor and extracting the detection signal through a capacitor. .

[0002]

2. Description of the Related Art FIG. 4 is a diagram showing a configuration example of an electrostatic hemispherical energy analyzer, and FIG. 5 is a diagram showing a configuration example of an electron multiplication type detection system. In the figure, 1 is a sample, 2 is an electron, 3 is an input lens, 4 is an entrance slit, 5 is a hemispherical analyzer, 6 is an inner sphere, 7 is an outer sphere, 8 is a detector (channeltron), and 9 is a microprocessor. (MPU).

The electrostatic hemispherical energy analyzer shown in FIG. 4 irradiates the surface of a sample 1 with an electron beam, an X-ray, or the like, and emits electrons 2 such as Auger electrons and photoelectrons radiated therefrom. To a detector (channeltron) 8 through which the energy spectrum is analyzed. The hemispherical analyzer 5 includes an inner sphere 6 and an outer sphere 7 having concentric spherical surfaces, and a plurality of detectors 8 are arranged side by side on a focus surface. Microprocessor (MP
U) 9 controls the potential and the like of each of the constituent elements 3 to 8 and performs processing of data taken in from the detector 8. The electrons 2 emitted from the surface of the sample 1 are decelerated and converged by the input lens 3 and then enter the entrance slit 4 of the hemispherical analyzer 5. The electrons 2 that have passed through the entrance slit 4 are orbited by the action of the electrostatic field applied to the inner sphere 6 and the outer sphere 7, reach the focus surface while dispersing energy, and are emitted by the plurality of detectors 8. Detected as intensity data.

In the electron multiplying detection system used in the above-mentioned electrostatic hemispherical energy analyzer, a high voltage HV is applied to the channeltron 11 and the collector 12 through bias resistors R ₁ and R ₂ as shown in FIG. Signals are extracted from the circuit 12 through a coupling capacitor C. When pulse measurement is performed in such an electron multiplying detection system, the stray capacitance around the collector must be reduced as much as possible in order to obtain a high wave height and responsiveness. For this reason, it is desirable that the bias resistor R ₂ and the coupling capacitor C be installed in a vacuum chamber.

[0005]

FIG. 6 is a diagram showing a conventional example of a multiplex detector (channeltron), and FIG. 7 is a diagram for explaining changes in the characteristics of the channeltron. However, in the case of performing multiplex detection, as shown in FIG.
-3, bias resistor R ₂₁ to R _23, coupling capacitors C ₁ ~
C _3, etc. will be placed on the vacuum side. One of the problems in such a multiplex detection system is that there is an individual difference in the optimal operating voltage of the channeltron. The number of output pulses with respect to the applied voltage is
As shown in FIG. 7, the output pulse number of the young channeltron A is saturated at a relatively low voltage, whereas the old channeltron B requires a high voltage.

However, in the conventional circuit as shown in FIG. 6, only the same voltage can be applied to any of the channel trons. If voltage is to be applied independently, it is necessary to introduce multiple systems of high voltage. From the demand for high voltage design
An increase in the shape and dimensions of the insulator poses a new problem.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to introduce one system of high voltage into a vacuum and to provide an optimum operating voltage to each channeltron.

For this purpose, the present invention provides an electron multiplexing detection apparatus having a plurality of channeltrons, which detects electrons by applying a high voltage to a vacuum through a bias resistor and takes out the detection signal through a capacitor. A variable bias resistor having a variable resistance value is provided corresponding to the channeltron. The variable bias resistor has an intermediate terminal, and the resistance is changed by changing a short position of the intermediate terminal. It is characterized in that it is configured as a bias resistor row unit that changes the value.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a multiplex detector according to the present invention.
HV is the supply voltage, C ₁ is the coupling capacitor, R ₁ , R ₂ ,
R ₂ ′ is a bias resistance, and R is the resistance of the channeltron itself.

In FIG. 1A, the channeltron 8
, The resistance R of the channeltron itself, the bias resistances R ₁ , R ₂ , and the coupling capacitor C ₁ show an example of a circuit configuration of one channeltron, and the applied voltage of the channeltron 8 is the supply voltage HV, the bias resistance R ₂ is determined by the resistance R of the channeltron itself. Therefore, focusing on the voltage applied to both ends of the channeltron 8, FIG.
This can be regarded as equivalent to the circuit of FIG. That is, the voltage V _C across the channeltron is

[0011]

(Equation 1) Becomes Therefore, if the bias resistor R ₂ ′ is changed using a variable resistor as shown in FIG.
Is constant, the voltage V _C across the channeltron can be changed. Therefore, if a mechanism for changing the bias resistance is provided for each channel, the operating voltage can be changed for each channeltron.

FIG. 2 is a diagram showing an embodiment of a multiplex detector according to the present invention, and FIG. 3 is a diagram showing an example of a bias resistor unit.

In FIG. 2, a plurality of channeltrons 8
_The supply voltage HV is supplied to ₁ , 8 ₂ and 8 ₃ through bias resistors R ₂₁ ′, R ₂₂ ′ and R ₂₃ ′ each using a variable resistor on the vacuum side. Therefore, the bias resistors R ₂₁ ′, R ₂₂ ′, and R ₂₃ ′ have a connection configuration as shown in FIG. 3A on the vacuum side. Specifically, as shown in FIG. 3B, a thin film resistor 21 is placed on a substrate as bias resistors R ₂₁ ′, R ₂₂ ′, and R ₂₃ ′, and a plurality of intermediate terminals 22 are provided on the way. , The intermediate terminal 22 is short-circuited,
The resistance value may be changed by changing the position. Further, as shown in FIG. 3C, the resistance value may be varied by inserting and removing a resistor 23 having a required value from the plug 24.

The selection of the resistance values of the bias resistors R ₂₁ ′, R ₂₂ ′, and R ₂₃ ′ depends on the saturation voltage V _{C for} each channel.
Is checked and the required V under the given supply voltage HV
Seeking bias resistor R ₂ as _C is obtained by the above equation (1), bias resistor, short the intermediate terminals 22 need to be close to this value, or to insert a resistor 23. This operation is performed for all channels. For this operation, the vacuum chamber must be leaked once, but there is no substantial inconvenience because the operation can be performed once for all channels. Further, when the configuration shown in FIG. 3C is employed, the resistance value may be changed to a required value.

Note that the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the bias resistor row unit may be formed compactly by integrating it with the coupling capacitor row unit or the like, and such a configuration is more desirable because the stray capacitance can be reduced.

[0016]

As is apparent from the above description, according to the present invention, the bias resistance row unit and the coupling capacitor row are provided in a vacuum and the bias resistance value is varied, so that the stray capacitance can be reduced. It is now possible to apply a saturation voltage (optimum operating voltage) value to each channeltron while achieving high-speed response and high wave height. Conventionally, the channeltron having the highest saturation voltage had to be adjusted, thereby shortening the lifetime of the channeltron. However, by applying the present invention, the lifetime of the channeltron used for multiplex detection can be reduced. Can be extended.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a multiplex detector according to the present invention.

FIG. 2 is a diagram showing an embodiment of a multiplex detector according to the present invention.

FIG. 3 is a diagram illustrating an example of a bias resistor unit.

FIG. 4 is a diagram illustrating a configuration example of an electrostatic hemispherical energy analyzer.

FIG. 5 is a diagram illustrating a configuration example of an electron multiplying detection system.

FIG. 6 is a diagram showing a conventional example of a multiplex detector (channeltron).

FIG. 7 is a diagram for explaining a change in characteristics of a channeltron.

[Explanation of symbols]

8 ... channeltron, HV ... supply voltage, C ₁ ... coupling _{capacitor, R 1, R 2, R} 2 '... bias resistor, the R ... channeltron own resistance

Claims (2)

[Claims] 1. An electron multiplexing detection device having a plurality of channeltrons for detecting electrons by applying a high voltage in a vacuum through a bias resistor and extracting a detection signal through a capacitor. And a bias resistor having a variable resistance value. 2. The electronic device according to claim 1, wherein the variable bias resistor has an intermediate terminal and is configured as a bias resistor row unit that changes a resistance value by changing a short position of the intermediate terminal. Multiplex detector.