JP2001015062A - Control power source for quadrupole electrode of quadrupole mass spectrometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control power source for a quadrupole electrode capable of operating a quadrupole mass spectrometer even in a region having a small mass number to be analyzed without using a diode vacuum tube. SOLUTION: In this power source, a high frequency transformer 10 is provided with a rectifier signal detection winding 12 independent of high frequency voltage generation secondary windings 22a and 22b. A winding ratio of the rectifier signal detection winding 12 to a primary winding 24 is set so as to generate a low high frequency voltage not to deteriorate a schottkey-barrier diode 14 having a low breakdown voltage. The diode 14 detects and rectifies the output high frequency of the rectifier signal detection winding 12 to generate a dc current. A dc amplifier 20 amplifies using the dc current voltage as a reference voltage so as to provide a desired ratio of the high frequency voltage to the dc voltage applied to a quadrupole electrode 104.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a control power supply for a quadrupole electrode of a quadrupole mass spectrometer. The quadrupole mass spectrometer is used for a pressure measuring device that measures a vacuum pressure lower than the atmospheric pressure.

[0002]

2. Description of the Related Art The resolution at the mass peak of a quadrupole mass spectrometer is determined by the ratio between the high-frequency voltage applied to the quadrupole electrode and the DC voltage, and the stability of the mass peak intensity is also stable at the high-frequency voltage and the DC voltage. Determined by gender. In general, a high-frequency transformer is used to generate a high-frequency voltage, and the high-frequency voltage generated on the high-frequency secondary side is directly applied to the quadrupole electrode. The high frequency voltage generated on the secondary side is
At the same time, it is taken out as a DC detection voltage proportional to the high-frequency voltage by the detection / rectification circuit. The DC detection voltage becomes an input voltage of the DC voltage amplification circuit, and generates a DC voltage to be applied to the quadrupole electrode.

Conventionally, high-frequency voltage detection and rectification circuits include:
Diode vacuum tubes have been widely used because of their high withstand voltage and good linearity in voltage-current characteristics. FIG. 2 shows an example of a conventional high-frequency generation circuit for applying a quadrupole voltage, in which a two-pole vacuum tube is used for a high-frequency voltage detection / rectification circuit. In FIG. 2, a high-frequency voltage generated by a high-frequency generator 100 including a high-frequency oscillator is boosted to a desired magnitude by a high-frequency transformer 102 and applied to a quadrupole electrode 104. The high-frequency voltage boosted to a desired magnitude and applied to the quadrupole electrode 104 is detected and rectified by the two-pole vacuum tube 106,
Generates a rectified signal. This detected / rectified signal is used as a reference voltage for generating a DC voltage proportional to the high-frequency voltage applied to the quadrupole electrode 104. The DC amplifier 108 receives the detected and rectified signal, and
The detection and rectification signal is amplified so that the ratio between the high-frequency voltage and the DC voltage applied to 04 takes a desired value, and a pair of ± DC voltages is generated. The pair of ± DC voltages generated by the DC amplifier 108 is provided to be superimposed on the high-frequency voltage by the secondary winding of the high-frequency transformer 102, and has a desired ratio between the high-frequency voltage and the DC voltage (+ DC voltage (+ High-frequency voltage) and (−DC voltage + high-frequency voltage) are applied to the quadrupole electrode 104. Note that in FIG.
Reference numerals 10, 112 and 114 indicate capacitors.

However, the manufacture of the two-electrode vacuum tube has already been discontinued in Japan, and the procurement of parts has become more difficult year by year. In addition, there has been a drawback that a separate power supply for the heater is required. For this reason, diodes of various specifications have been used instead of the two-electrode vacuum tube. FIG. 3 shows a conventional example in which a diode is used in a high-frequency voltage detection / rectification circuit in a quadrupole voltage application high-frequency generation circuit. The circuit configuration shown in FIG. 3 is the same as the circuit configuration shown in FIG. 2 except that a diode 116 is used instead of the two-electrode vacuum tube 106 shown in FIG. The function of detecting and rectifying the high-frequency voltage of the diode 116 is the same as that of the two-pole vacuum tube, and the operation of the circuit of FIG. 3 is the same as the operation of the circuit of FIG. Of the diodes used in the configuration shown in FIG. 3, the Schottky barrier diode is excellent in high-speed response, but has a low reverse withstand voltage and is limited to a case where the peak voltage of the high-frequency voltage is within several hundred volts. Therefore, the mass number that can be analyzed cannot be used at several hundred amu. On the other hand, when the peak voltage of the high-frequency voltage is several hundred volts or more, a diode having a high withstand voltage of several kV, for example, is used, and in this case, a forward voltage drop is large, and However, in the case of 1 to 2 amu, the peak value of the high-frequency voltage was also 1 V or less, so that a detection / rectification signal could not be taken out in this range. However, 2
Since amu corresponds to the mass peak of H ₂ ⁺ and is a very important peak as a mass spectrum, it is inevitable to use a two-electrode vacuum tube having a high withstand voltage and a small forward voltage drop.

[0005] As described above, conventionally, a diode vacuum tube and a diode have been selectively used for a high-frequency voltage detection / rectification circuit according to the specifications of a quadrupole mass spectrometer.

[0006]

SUMMARY OF THE INVENTION The present invention provides a control power supply for a quadrupole electrode capable of operating a quadrupole mass spectrometer even in a region having a small analytical mass number without using a two-pole vacuum tube.

[0007]

In order to solve the above-mentioned problems, a reference for generating a DC voltage applied to the quadrupole electrode based on a high-frequency voltage applied to the quadrupole electrode of the quadrupole mass spectrometer is provided. According to the control power supply for a quadrupole electrode of the quadrupole mass spectrometer of the present invention, which has a DC voltage reference voltage generation unit that generates a voltage, the DC voltage reference voltage generation unit is applied to the quadrupole electrode. A high-frequency transformer for generating a high-frequency voltage having an amplitude smaller than the amplitude of the high-frequency voltage, a high-frequency voltage generated by the high-frequency transformer for reference voltage is detected and rectified, and a direct current applied to the quadrupole electrode is detected. A solid-state detecting and rectifying element for generating a reference voltage for generating a voltage, and the high-frequency transformer for reference voltage is configured to apply a high-frequency voltage to which the solid-state detecting and rectifying element is applied. It characterized by having a turns ratio resulting in a high frequency voltage having a magnitude amplitude of not degrade Ri.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a preferred embodiment of a control power supply for a quadrupole electrode of the quadrupole mass spectrometer of the present invention. In FIG. 1, components denoted by the same reference numerals as those in FIGS. 2 and 3 indicate the same or similar components, and description thereof will not be repeated. Reference numeral 10 denotes a high-frequency transformer, which is a conventional high-frequency transformer shown in FIGS.
2 is the same as the high-frequency transformer 102 except that the rectification signal detection winding 12 is provided separately.
This is different from the conventional high-frequency transformer 102. A solid-state detection / rectification element 14 is connected to one output end of the rectification signal detection winding 12,
Preferably, a cathode of the Schottky barrier diode is connected, and a detection signal smoothing capacitor 16 is connected between the anode of the Schottky barrier diode 14 and the other output terminal of the rectification signal detection winding 12. The anode of the Schottky barrier diode 14 is also connected to a DC amplifier 20 via a detection signal smoothing resistor 18. + Of DC amplifier 20 that generates a pair of ± DC voltages
And -DC voltage output are supplied to the high-frequency transformer 10 respectively.
Are connected to the ends of the two secondary windings 22a and 22b opposite to the ends connected to the quadrupole electrode 104. The high frequency generator 100 is connected to the primary winding 24 of the high frequency transformer 10.

The winding ratio between the primary winding 24 of the high-frequency transformer 10 and the high-frequency voltage generating secondary windings 22a and 22b is determined by increasing the high-frequency voltage from the high-frequency generator 100 and applying a desired amplitude to the quadrupole electrode 104. Is set to a predetermined fixed ratio so that a high-frequency voltage having the following can be applied. The turn ratio of the rectified signal detection winding 12 to the primary winding 24 is fixed so that the peak voltage of the high frequency voltage applied to the low reverse breakdown voltage Schottky barrier diode 14 is within several hundred volts. Set to the ratio. Therefore,
Since the respective winding ratios of the high frequency voltage generating secondary windings 22a and 22b and the rectified signal detection winding 12 to the primary winding 24 are fixed, the rectified signal detection winding 12 has four turns. A high-frequency voltage proportional to the high-frequency voltage applied to the pole electrode 104 is obtained with high precision, and the obtained high-frequency voltage is detected and rectified by the Schottky barrier diode 14. As a result, the high-frequency voltage is applied to the quadrupole electrode 104. A DC voltage proportional to the high-frequency voltage with high precision is obtained via the smoothing capacitor 16 and the resistor 18. That is,
The DC voltage obtained by the rectification signal detection winding 12, the Schottky barrier diode 14, the smoothing capacitor 16 and the resistor 18 can be used as a reference voltage for generating a DC voltage applied to the quadrupole electrode 104. . The DC amplifier 20 outputs the output DC voltage of the resistor 18 that can be used as a reference voltage to the quadrupole electrode 10.
Amplification is performed at a predetermined amplification factor such that the ratio between the high-frequency voltage and the DC voltage applied to 4 becomes a desired value. The reference voltage amplified by the DC amplifier 20 is superimposed on the high-frequency voltage boosted by the secondary windings 22a and 22b, and the superimposed (+ DC voltage + high-frequency voltage) and (+ DC voltage-high-frequency voltage) A high frequency voltage and a DC voltage are applied to quadrupole electrode 104 at a desired ratio.

In one embodiment of the present invention shown in FIG.
The detection and rectification signal detection winding 12 is separately provided to the high-frequency transformer 10 from the high-frequency voltage generation secondary windings 22a and 22b.
In addition, the Schottky barrier diode having a low reverse withstand voltage can be provided with a turn ratio to the primary winding 24 so as to be compatible with the withstand voltage of the detection and rectification diode used. It can be used as a rectifying element.

In the present invention, in principle, the rectified signal detecting winding 12 is connected to the high frequency voltage generating secondary windings 22a, 22a.
It is not always necessary to provide it separately from b. A tap may be provided on a part of the high-frequency voltage generating secondary windings 22a and 22b and taken out. Further, in principle, the present invention relates to a quadrupole electrode 10 obtained by a high-frequency transformer 10 instead of the high-frequency transformer using the rectified signal detection winding 12.
The high-frequency voltage applied to 4 is stepped down by a high-frequency transformer for voltage division, and the stepped-down high-frequency voltage is detected and rectified by a solid-state detecting / rectifying element such as a Schottky barrier diode to generate a DC voltage for a reference voltage. You may.

The high frequency generated by the high frequency oscillator of the high frequency generator 100 is modulated by a sawtooth wave by a balanced modulator. As a result, the amplitude of the high frequency becomes a magnitude corresponding to the amplitude of the sawtooth wave of the modulation signal. . That is, if the amplitude of the sawtooth wave deviates from the desired magnitude, the absolute value of the high-frequency amplitude also deviates. Therefore, in a high-precision quadrupole mass spectrometer, a signal obtained by detecting and rectifying a high-frequency voltage applied to a quadrupole electrode is usually used so that the amplitude of the sawtooth wave does not shift. Give feedback. The DC voltage obtained by using the high-frequency transformer and the solid-state detection and rectification element that generate a low-frequency voltage that does not deteriorate the solid-state detection and rectification element of the present invention is used to control the amplitude of the sawtooth wave to a desired magnitude. It can be used as the above feedback signal.

[0013]

The present invention uses a high-frequency transformer that generates a low-frequency voltage that does not deteriorate the solid-state detection and rectification element and a solid-state detection and rectification element. However, a quadrupole mass spectrometer can be operated. That is, regardless of the specifications of the quadrupole mass spectrometer, a solid-state detection / rectification element, particularly a Schottky barrier diode having a low reverse withstand voltage, can be used for the high-frequency voltage detection / rectification circuit.

Since a two-pole vacuum tube is not used, a heater power supply for heating the cathode is not required. Further, since the two-electrode vacuum tube can be replaced with a solid-state detection / rectification element such as a small-sized diode, it is possible to save the installation space for components.

[Brief description of the drawings]

FIG. 1 shows a preferred embodiment of a control power supply for a quadrupole electrode of a quadrupole mass spectrometer of the present invention.

FIG. 2 shows a high-frequency generation circuit for applying a quadrupole voltage;
An example of a conventional technique using an extremely vacuum tube for a high-frequency voltage detection and rectification circuit will be described.

FIG. 3 shows an example of a conventional high frequency generating circuit for applying a quadrupole voltage, in which a diode is used for a high frequency voltage detecting and rectifying circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 High frequency transformer 12 Rectification signal detection winding 14 Schottky barrier diode 16 Capacitor 18 Resistance 20 DC amplifier

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Seiji Hiroki 801 Mukaiyama, Naka-machi, Naka-machi, Naka-gun, Ibaraki Pref. No.212 No.212 Tsukubarika Seiki Co., Ltd. F-term (reference) 2F055 AA40 BB08 CC45 DD20 EE40 FF07 GG31 5C038 JJ06 JJ07

Claims (4)

[Claims] 1. A DC voltage reference voltage generator for generating a reference voltage for generating a DC voltage applied to a quadrupole electrode based on a high frequency voltage applied to the quadrupole electrode of a quadrupole mass spectrometer. A control power supply for a quadrupole electrode of a quadrupole mass spectrometer, wherein the DC voltage reference voltage generation unit generates a high-frequency voltage having an amplitude smaller than an amplitude of a high-frequency voltage applied to the quadrupole electrode. A high-frequency transformer for voltage; and a solid-state detector for detecting and rectifying the high-frequency voltage generated by the high-frequency transformer for reference voltage, and generating a reference voltage for generating a DC voltage applied to the quadrupole electrode.
A rectifying element, wherein the high-frequency transformer for reference voltage has a turns ratio that generates a high-frequency voltage having an amplitude that does not deteriorate due to the high-frequency voltage applied to the solid-state detection / rectifying element. Control power supply for the quadrupole electrode of the pole mass spectrometer. 2. A high-frequency voltage detecting secondary winding is provided independently of a secondary winding of a high-frequency voltage high-frequency transformer for generating a high-frequency voltage applied to the quadrupole electrode. The control power supply for quadrupole electrodes of the quadrupole mass spectrometer according to claim 1, wherein 3. A DC voltage which is proportional to a high frequency voltage applied to said quadrupole electrode and superimposed on said high frequency voltage and directly applied to said quadrupole electrode is applied to a reference voltage generated by said solid state detection / rectification element. The control power supply for a quadrupole electrode of a quadrupole mass spectrometer according to claim 1 or 2, further comprising a DC amplifying unit that generates the DC power based on the DC power. 4. The control power supply for a quadrupole electrode of a quadrupole mass spectrometer according to claim 1, wherein the solid-state detection / rectification element is a diode.