JPH04296435A - Neutral particle energy analyzer - Google Patents

Abstract

PURPOSE:To solve problems of a fixing space, fixing dimension and the like by detecting different energy of charged particles by the use of one charged particle detector. CONSTITUTION:On an output side of a charged particle exchanger, there are provided a pair of magnets 21 having deflection sides of an almost quadratic curve in order to deflect charged particles according to their energy so as to converge them to one point through different orbits. One detector 27 is disposed on a convergent point of the charged particle, for detection of the charged particle having different energy.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a neutral particle energy analyzer for measuring neutral particles and determining their energy.

0002

2. Description of the Related Art Conventionally, this type of neutral particle energy analyzer has been designed to collect neutral particles 3 emitted from plasma 2 of a neutral particle source 1 through a vacuum connection tube 4 into a vacuum vessel 5, as shown in FIG.
The particles are introduced into a stripping cell 6 as a charged particle exchanger in the interior, where they are ionized by an internal gas and converted into charged particles, and then enter a charged particle deflector 7. This charged particle deflector 7 applies an electric field or a magnetic field to deflect charged particles according to their particle energy and emit them to different positions.

Furthermore, charged particle detectors 8 are arranged at the arrival points of charged particles having different energies to detect charged particles, and a discriminator 9 and an amplifier 10 are installed for each charged particle detector 8. Then, by counting the number of charged particles with the counter 11, an energy spectrum as shown in FIG. 6 is obtained, and the neutral particle energy is determined from the shape of this energy spectrum.

Therefore, in the above-mentioned apparatus, a charged particle detector 8 is installed for each energy of the loaded particle, so a large number of charged particle detectors 8 are required, and Each of these detectors 8... has a discriminator 9..., an amplifier 10..., a counter 11...
needed to be connected.

[0005]

[Problems to be Solved by the Invention] Therefore, in the above-mentioned device, in addition to the charged particle detector 8..., a large number of signal processing circuits are required, so that it is not only expensive, but also expensive. The overall circuit configuration is complex, and sufficient installation space must be secured and a large number of charged particle detectors 8...
Since it is necessary to consider the accuracy of the mounting dimensions, etc., the design is extremely complicated.

The present invention has been made in view of the above-mentioned circumstances, and allows charged particles of different energies to be detected by a single charged particle detector, which can be realized at low cost and saves installation space, installation dimensions, etc. The purpose is to provide a neutral particle energy analyzer that can easily solve difficult problems.

[0007]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the neutral particle energy analyzer according to the present invention has different polarities on the output side of the charged particle exchanger depending on the energy of the charged particles. In order to converge the charged particles on one point through the trajectory, a pair of magnets each having a deflection side in the shape of an approximately quadratic curve is arranged, and a detector is provided at the convergence point of the charged particles. The charged particle detector is configured to detect charged particles of different energies.

[0008]

[Operation] Therefore, by taking the above-mentioned measures, the present invention arranges a pair of magnet bodies whose side on the charged particle deflection side has a substantially quadratic curve, and deflects each charged particle according to the energy of the charged particle. By converging on a certain orbit while changing the orbit, it is possible to detect charged particles by placing one charged particle detector at this convergence point, and to detect charged particles within a predetermined time from the output of this charged particle detector. This method obtains the energy spectrum of neutral particles by acquiring the number of charged particles with different energies.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the apparatus of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a charged particle deflector, which is constituted by a pair of electromagnetic bodies 21 of a predetermined shape as described later. Specifically, this electromagnetic body 21 has a side 23 on the non-deflecting side with respect to the incident axis (X axis) of charged particles 22 sent from a stripping cell serving as a charged particle exchanger, parallel to the incident axis. The side 24 on the incident end side of the charged particles 22 is formed horizontally to the axis (Y axis) perpendicular to the incident axis, and the side 24
The length is relatively short. Furthermore, the side 23
A side 25 on the opposite side, that is, on the deflection side with respect to the incident axis, is formed parallel to the incident axis from the lower end of the side 24 to a predetermined point P, and changes the trajectory from the point P according to the energy of the charged particle 22. In order to obtain a deflection curve that converges to one point while changing, it is formed into a substantially quadratic curve shape.

[0010]The remaining side 26 of this electromagnetic body 21
is formed parallel to the Y axis, and the intersection with the side 25 is specified as point Q for convenience. Therefore, the side 25 connecting points P and Q is formed into a substantially quadratic curve shape. That is, the shape between point P and point Q is determined by applying a magnetic field to the electromagnets 21 serving as the pair of electrodes from the inside to the outside in the drawing paper.
A charged particle 22 in 21 is deflected according to its particle energy and passes through different trajectories until it reaches a point (X0
, Y0 ), and the coordinates of the point where the charged particles 22 with each energy cross the side 25 are (
X, Y), then X = [X0 ・Y + {X0 2 ・Y2 + (Y0
2 −Y2 )Y2 }]1/2

/(Y+
Y0) is determined based on the formula. In addition, (a), (b), (c), (d), and (e) in the figure are 60ke.
v, 120kev, 180kev, 240kev
, 300 keV.

[0011] Then, one charged particle detector 27 such as a surface barrier semiconductor detector SSD or a Pin diode detector is placed at the convergence point obtained as described above. moreover,
A pulse height analyzer 30 is connected to the output side of the charged particle detector 27 via a preamplifier 28 and a linear amplifier 29, as shown in FIG.

Therefore, according to the configuration of the embodiment as described above, the pair of electromagnets 21, 21 are used, and the side 25 of the charged particle deflector is given a predetermined shape to apply a magnetic field in a predetermined direction to deflect incident charged particles. When 22 is deflected, the charged particle 22
As shown in FIG. 1(b), the particles converge on a single point (X0, Y0) through different trajectories depending on their energy, so if the charged particle detector 27 is placed at this convergence point, each energy It is possible to detect charged particles 22 according to. Furthermore, when the output of this charged particle detector 27 is amplified by a preamplifier 28 and then waveform-shaped and amplified by a rear amplifier 29, outputs of various peak values e1, e2, e3, ... according to energy as shown in FIG. is obtained, the wave height analyzer 30 counts the same wave height value e1 at a predetermined time Δt, and plots the wave height value on the horizontal axis.
By plotting the count value on the vertical axis, a neutral particle energy spectrum as shown in FIG. 4 can be obtained.

[0013]

[Effects of the Invention] As detailed above, according to the present invention, 1
It is possible to detect charged particles with different energies with a single charged particle detector, which can reduce costs and achieve a very simple configuration, and can improve problems such as installation space and installation dimensions. We can provide neutral particle energy analyzers.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram schematically showing the device of the present invention, with FIG. 1(a) being a front view and FIG. 1(b) being a side view.

FIG. 2 is a block diagram showing a signal processing system for charged particle detector output in the device of the present invention.

FIG. 3 is a distribution diagram of peak values of detected energy in the device of the present invention.

FIG. 4 is an energy spectrum diagram illustrating the device of the present invention.

[Figure 5] Block diagram of conventional equipment.

[Figure 6] Energy spectrum diagram of conventional equipment.

[Explanation of symbols] 21...Electromagnetic body, 22...Charged particles, 25...Deflection side,
27... Charged particle detector, 30... Wave height analyzer.

Claims (1)

[Claims] Claim 1. A neutral particle energy analyzer that detects charged particles obtained by ionizing incident neutral particles with a charged particle exchanger by deflecting them according to differences in their charged particle energies, wherein the charged particle exchanger On the output side of the device,
In order to deflect the charged particles according to their energy and converge them on a single point through different trajectories, a pair of magnet bodies each having a deflection side shaped like a substantially quadratic curve is arranged, and a convergence point of the charged particles is arranged. 1. A neutral particle energy analyzer characterized in that a single detector is provided in the detector to detect charged particles of different energies.