JPH01239755A - Neutral particle energy analyzing device - Google Patents

Abstract

PURPOSE:To compensate the influence of the hysteresis of an electromagnet and to analyze the energy of neutrons highly accurately by comparing a magnetic field to measure and the magnetic field obtained by the standard current value, and feeding the correction current responding to the resultant deviation magnetic field to an exciting coil for correction. CONSTITUTION:Not only the main exciting coil 14, but also an exciting coil 15 for correction are wound on an electromagnet 13, and the magnetic field generated when a standard current responding to the injection of the maximum neutron energy to a detector 17 positioned at the maximum Raman radius is fed to the main exciting coil 14 is measured by a magnetic field measuring device 19. At the same time, a correction current responding to the deviation between the magnetic field to measure and the magnetic field obtained by the standard current is fed to the correction exciting coil 15 from a correction exciting power source 21. As a result, even though a variation of the generated magnetic field is generated by the hysteresis property of the electromagnet 13, it can be compensated by the coil 15, and the neutral particle energy can be analyzed highly accurately.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention is a method for analyzing the energy of neutral particles from the momentum of ions obtained by charge-exchanging neutral particles with a neutral gas. The present invention relates to improvements in neutral particle energy analyzers, and particularly to neutral particle energy analyzers that correct magnetic field fluctuations due to hysteresis of an electromagnet that imparts Larma rotational motion to charge-exchanged ions.

(Prior Art) As shown in FIG. 4, in a conventional analyzer of this type, neutral particles 2 from a plasma 1 are charge-exchanged and ionized by a neutral gas in a stripping cell 3, and then an electromagnet is used. The magnetic field from 4 causes a Rama rotational movement, and the ion arrival point due to the rotational movement is detected by the detector 5. ... are installed, and the energy of the neutral particles 1 is analyzed by detecting the momentum of ions using the detectors 5, ....

By the way, conventionally, as a means for imparting a Larma rotational motion to charge-exchanged ions, an excitation coil is wound around the electromagnet 4, and a maximum current is applied from an excitation power source to the excitation coil such that the ions are given a rotational motion of a maximum Larma radius RLff1aX. After that, the current flowing into the excitation coil is gradually increased or decreased to find the point where the detector 5 has the maximum output, and the energy of the neutral particles is analyzed from the detected value of the detector 5 at that time. .

(Problem to be Solved by the Invention) However, the above-described magnetic field generating means is limited to the electromagnet 4
A hysteresis phenomenon occurs due to inherent material properties, and as shown in Figure 5, even when the same excitation current is applied, the electromagnet 4
The generated magnetic field differs depending on the temperature or current value, etc., and this difference in the generated magnetic field causes a measurement error in the neutral particle energy, making it impossible to measure with high precision.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a neutral particle energy analyzer that can compensate for the effects of hysteresis of an electromagnet and analyze the energy of neutral particles with high precision. With the goal.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the neutral particle energy analyzer according to the present invention applies a magnetic field from an electromagnet to ions obtained from neutral particles by charge exchange. In a neutral particle energy analyzer that deflects and analyzes the energy of the neutral particles from the deflected ions, a reference current is applied to a main excitation coil and a correction excitation coil respectively wound around the electromagnet, and to the main excitation coil. Magnetic field ΔP1 constant hand pitching means for measuring the magnetic field generated when flowing this magnetic field i'JllI
and a magnetic field correction means that compares the measurement magnetic field measured by the determination means with the magnetic field to be obtained by the reference current value, and generates a correction magnetic field by flowing a correction current in accordance with the deviation magnetic field to a correction excitation coil. It is something that

(Function) Therefore, the present invention has the above-mentioned means.
When a reference current is applied to the main excitation coil, a reference magnetic field cannot be obtained due to the influence of hysteresis of the electromagnet. However, the actual generated magnetic field affected by hysteresis is measured by a magnetic field measuring means, and this measured magnetic field and the A desired reference magnetic field is generated from the electromagnet by comparing the reference magnetic field to be obtained by the reference current and flowing a correction current corresponding to the deviation magnetic field to the correction excitation coil, causing the charge-exchanged ions to rotate. It is something.

(Example) An example of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 1 is a side view of the device main body, FIG. 2 is a plan view of the device main body, and FIG. 3 is an overall configuration diagram of the device of the present invention. In these figures, 10 is a device housing,
Neutral particles from the plasma undergo charge exchange with a neutral gas in the stripping cell 11, and enter the stripping cell 11 in an ionized state.

On the exit side of the stripping cell 11, electromagnets 13 made of electromagnetic soft iron or low carbon steel plate are arranged on both sides of the stripping cell 11 to form a deflection gap 12 for rotationally moving the ions. A correction excitation coil 15 is wound. This main excitation coil 14 is a coil through which a large reference current flows.Therefore, in order to prevent temperature rise, a holo-conductor (square hollow steel tube, etc.) 16 is provided inside the coil, and cooling water is provided inside these holo-conductors 16. It is being distributed. On the other hand, the correction excitation coil 15 is wound with a thin insulated wire with a large number of turns in order to flow a relatively small current. 17. ... is a detector that detects the rotational momentum of ions deflected by the magnetic field from the electromagnet 13. Note that the main excitation coil 14 is supplied with a reference current from the reference excitation power supply 17 to create a magnetic field necessary for the maximum neutral particle energy to reach the detector 17 at the position corresponding to the maximum Larma radius RL l1ax.

In addition, in this device, for example, the ion deflection gap 1
A magnetic field measuring device 19 is provided at a portion corresponding to 2, and the measurement magnetic field signal measured by this measuring device 19 is sent to the comparison calculation means 20.
is supplied to one input terminal of

The other input terminal of this comparison calculation means 20 is connected to the reference excitation power supply]
8, a reference magnetic field equivalent signal corresponding to the basic current value is input. This comparison calculation means 2o compares the reference magnetic field signal from the reference excitation power supply 18 with the measurement magnetic field signal, and supplies a signal corresponding to the deviation magnetic field to the correction magnetic field power supply 2], and sends a signal from the correction magnetic field power supply 21 to the correction excitation coil. 15, a correction current is supplied to generate a magnetic field equivalent to the deviation magnetic field.

Next, the operation of the apparatus configured as above will be explained.

First, neutral particles from the plasma are transferred to the strip jig cell 1.
The neutral gas inside 1 undergoes charge exchange and becomes ions. At this time, a reference current is applied to the main excitation coil 14 from the reference excitation power supply 18 . As a result, the charge-exchanged ions receive a magnetic field from the electromagnet 13 according to the reference current supplied to the main excitation coil 14, and perform a 180° ram rotational movement, and the detector 1 located at the maximum ram radius RLaax
7, the maximum neutral particle energy is incident.

Incidentally, the electromagnet 13 generates a magnetic field proportional to the reference current, but the generated magnetic field fluctuates due to hysteresis specific to the material of the electromagnet 13. Therefore, when the electromagnet 13 generates a magnetic field, the magnetic field measuring device 19 measures the generated magnetic field by Δ-
1, and compares this δP1 constant magnetic field signal with a reference magnetic field signal required for the maximum neutron energy incident on the detector 17 at the maximum Larma radius position by the reference excitation power source 18.
Here, the measurement magnetic field signal and the reference magnetic field signal are compared, and a correction current required to generate a magnetic field corresponding to the deviation magnetic field is determined and supplied to the correction excitation power supply 21. In this correction excitation power supply 21, by flowing a current corresponding to the deviation magnetic field to the correction excitation coil 15, a magnetic field that is the total of the magnetic field generated by the main excitation coil 14 and the magnetic field generated by the correction excitation coil 15, that is, a reference current The reference magnetic field to be generated can be generated by

Therefore, according to the configuration of the embodiment as described above, the electromagnet 1
In addition to the main excitation coil 14, a correction excitation coil 15 is wound around the main excitation coil 14, and a reference current corresponding to the maximum neutron energy is applied to the detector 17 located at the maximum Larma radius is applied to the main excitation coil 14. A magnetic field measuring device 19 measures the magnetic field generated when the current is generated, and a correction current is supplied from the correction excitation power source 21 to the correction excitation coil 15 in accordance with the deviation between the measured magnetic field and the magnetic field obtained by the reference current. Even if the generated magnetic field fluctuates due to the hysteresis characteristic of the electromagnet 13, it can be compensated for by generating a magnetic field corresponding to the fluctuation by the correction excitation coil 15, and the neutral particle energy can be analyzed with high precision. Furthermore, since the correction excitation coil 15 is wound with a large number of turns of thin insulated wire, it is possible to reliably compensate for magnetic field fluctuations by passing a small current.

In addition, as described above, since a magnetic field is generated and corrected according to the deviation between the magnetic field equivalent to the reference current and the measured magnetic field, it is easy to calibrate the energy even if the magnetic field fluctuates due to changes in ambient temperature or changes over time, for example. It can be carried out.

In the above embodiment, the generated magnetic field is measured using the magnetic field hp + constant device 19, but the generated magnetic field may also be measured from changes in the magnetic flux using, for example, a magnetic flux detection coil. In addition, the present invention can be implemented with various modifications without departing from the gist thereof.

[Effects of the Invention] As described in detail above, according to the present invention, a correction excitation coil is provided separately from the main excitation coil, and the correction excitation coil is adjusted according to the deviation between the actually measured magnetic field and the reference magnetic field corresponding to the reference current flowing to the main excitation coil. Since the current is passed through the correction coil, it is possible to reliably compensate for fluctuations in the magnetic field due to hysteresis of the electromagnet, and it is possible to provide a neutral particle energy analyzer that can analyze neutral particle energy with high precision.

[Brief explanation of the drawing]

Figures 1 to 3 are shown to explain one embodiment of the neutral particle energy analyzer according to the present invention.
Fig. 1 is a schematic side view of the internal structure of the main body of the device, partially cut away, Fig. 2 is a schematic plan view of the internal structure of the main body of the device, partially shown in cross section, and Fig. 3 is the entire device. Configuration diagram,
FIG. 4 is a basic configuration diagram of a commonly used neutral particle energy analyzer, and FIG. 5 is a diagram showing the hysteresis characteristics of an electromagnet that rotates charge-exchanged ions. DESCRIPTION OF SYMBOLS 1... Plasma, 2... Neutral particle, 11... Stripping cell, 13... Electromagnet, 14... Main excitation coil, 15... Excitation coil for correction, 17... Detection 18... Reference excitation power supply, 19... Magnetic field measuring device,
20... Comparison calculation means, 21... Correction excitation power supply. Applicant's agent Patent attorney Takehiko Suzue Wk1 Figure 2

Claims (1)

[Scope of Claim] A neutral particle energy analyzer that deflects ions obtained from neutral particles by charge exchange by applying a magnetic field from an electromagnet, and analyzes the energy of the neutral particles from the deflected ions, the electromagnet comprising: A main excitation coil and a correction excitation coil wound around each other, a magnetic field measurement means for measuring a magnetic field generated when a reference current is passed through the main excitation coil, a measurement magnetic field measured by the magnetic field measurement means, and a magnetic field measured by the magnetic field measurement means. Neutral particle energy comprising: magnetic field correction means that compares the magnetic field to be obtained by a reference current and flows a correction current corresponding to the deviation magnetic field to the correction excitation coil to generate a correction magnetic field. Analysis equipment.