CN116840334B - In-situ joint measurement analysis method for silicon oxygen isotope micro-region of ion probe - Google Patents
In-situ joint measurement analysis method for silicon oxygen isotope micro-region of ion probe Download PDFInfo
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- 238000004458 analytical method Methods 0.000 title claims abstract description 71
- 239000000523 sample Substances 0.000 title claims abstract description 68
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- 238000005259 measurement Methods 0.000 title claims abstract description 25
- OBNDGIHQAIXEAO-UHFFFAOYSA-N [O].[Si] Chemical compound [O].[Si] OBNDGIHQAIXEAO-UHFFFAOYSA-N 0.000 title claims abstract description 18
- 238000000034 method Methods 0.000 claims abstract description 42
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- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J49/00—Particle spectrometers or separator tubes
- H01J49/26—Mass spectrometers or separator tubes
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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Abstract
The invention relates to a high-resolution high-sensitivity secondary ion probe mass spectrometer (hereinafter referred to as an ion probe) isotope ratio measurement technology, in particular to an ion probe silicon oxygen isotope micro-region in-situ joint measurement analysis method. And dividing an experimental analysis period T of the ion probe into three time slices, carrying out peak jump analysis between different experimental periods according to the time slices, keeping a sample table stationary in the whole analysis period T, bombarding a sample target at the same position by using the same ion beam, and sequentially analyzing two isotopes of Si and O to realize in-situ joint measurement analysis of micro-areas of the two isotopes of Si and O. Provides a new method for observing Si-O isotope cooperative change rules in situ in micrometer scale, and the fine geochemistry researches such as the formation mechanism of the ribbon-shaped iron-containing construction cause and the ferrosilicon rhythm layer of the precambrian. The aggregation of polishing substances on the surface or in scratches of the sample in the polishing process is avoided, and the analysis efficiency is greatly improved.
Description
Technical Field
The invention relates to a high-resolution high-sensitivity secondary ion probe mass spectrometer (hereinafter referred to as an ion probe) isotope ratio measurement technology, in particular to an ion probe silicon oxygen isotope micro-region in-situ joint measurement analysis method.
Background
The isotope and component contents of different crystal domains of a single mineral are subjected to micro-region in-situ analysis by utilizing an ion probe, so that geological action and evolution processes can be finely described, and phenomena and rules which cannot be observed by a conventional method are revealed. The O isotope micro-region in-situ analysis is widely applied as a conventional means, and the test precision is improved from 1%o (2 SD) to 0.2%o (2 SD). However, si isotope analysis is still the dominant overall analysis compared to O isotopes. This makes "disjointing" of the Si-O analysis technique, which is reflected in the decoupling of the method, difficult to interpret data when performing micro-domain analysis of silicate minerals. Thus, in situ Si-O isotope analysis is the most effective method to solve this problem. The Si-O isotope joint measurement analysis method has a unique point for solving some key geological problems, and is particularly suitable for researching the in-situ observation of Si-O isotope cooperative change rules at the mu m scale. The advantages are that: the same beam of ions is adopted to bombard the same position, so that the micro-region in-situ analysis of two elements is truly realized. The method omits repeated taking out of the sample target, polishes and eliminates the existing denuded pits, avoids the aggregation of polishing substances on the surface or in scratches of the sample in the polishing process, and greatly improves the analysis efficiency of the instrument. Therefore, the research of the Si-O isotope micro-region in-situ joint detection analysis technology is very necessary, a conventional analysis flow is established, and the development of geological application has important practical significance. The difficulty of establishing the ion probe Si-O isotope micro-region in-situ joint detection analysis method is that: the existing ion probe method cannot measure all isotope spectrum peaks of Si and O elements at the same time due to factors such as magnetic field dispersion (magnetic field radius) and the number of detectors.
Disclosure of Invention
The invention aims to provide an ion probe silicon oxygen isotope micro-region in-situ joint detection analysis method, so as to solve the problems in the prior art.
An in-situ joint detection analysis method for silicon oxygen isotope micro-regions of an ion probe is characterized in that an experimental analysis period T of the ion probe is divided into three time slices, peak jump analysis is carried out among different experimental periods according to the time slices, a sample table is kept static in the whole analysis period T, a sample target at the same position is bombarded by the same ion beam, two isotopes of Si and O are sequentially analyzed, and in-situ joint detection analysis of the silicon oxygen isotope micro-regions is realized.
As preferable: in the bombardment process, a multi-receiver repositioning method is adopted, a piezoelectric ceramic element is introduced to drive a receiver, the expansion characteristic of piezoelectric ceramic after being electrified is utilized to enable a guide rail and a guide rail to creep, so that relative motion is formed, the piezoelectric ceramic element and a grating ruler are preset in a crossed roller guide rail to drive high-resolution movement of the receiver, the shape of the peak top of a spectrum peak of a received signal is combined to judge whether the receiver reaches an optimal receiving position, and meanwhile, an instruction can be sent to drive the receiver to move until the shape of the peak top of the spectrum peak of the received signal meets the requirement, so that high-precision repositioning of the receiver position is realized.
As preferable: in the peak jump analysis process of the mass spectrometer, a high-stability magnetic field control method is adopted to change a magnetic field control structure, 4 low-magnetic field Hall detectors are added on the basis of the original 4 standard Hall detectors, a fuzzy logic control algorithm is adopted to generate a nonlinear transfer function corresponding to a magnetic field and control current, and control parameters of the nonlinear transfer function are adjusted to adapt to step changes of different levels, and the stability time of all incremental changes is reduced to the greatest extent.
As preferable: an experimental analysis period T was 21 minutes, divided into T 1 、T 2 And T m Three time slices, where t=t 1 +T m +T 2 ，T 1 For Si isotope analysis time, T 2 For O isotope analysis time, T m For switching the settling time of the magnetic field, e.g. at T 1 Periodic reception by LM and HM Faraday cups, respectively 28 Si and 30 after the Si signal and Si isotope analysis are completed, at T 2 The Faraday cup receiving is respectively utilized for LM, AA and HM in the period 16 O、 17 O、 18 O signal, magnetic field switching stabilization time is period T m 。
As preferable: during the analysis of the ion probe, the program controlled amplifier connected to the rear end of the Faraday cup is automatically regulated by control software, the background noise base line is dynamically regulated according to the feedback signal, and the automatic tuning in the high-precision detection process of Si and O isotopes is realized by combining a spectral peak processing technology.
As preferable: control deviceThe control software is written by using LabVIEW graphical language, and the control software controls a relay connected to the rear end of the Faraday cup by controlling a PCII/O interface card of a computer slot to realize the Faraday cup 10 10 、10 11 、10 12 And switching of omega range, and simultaneously, automatically closing gate valves at inlets of the multiple receivers according to user setting, and dynamically adjusting background noise baselines of the multiple receivers according to feedback signals.
As preferable: the resistor connected with the rear end of the Faraday cup receiver is replaced by a capacitor, so that the Faraday cup receiver works in a Faraday cup capacitor amplifier mode, the accurate measurement of the ion intensity is realized by measuring the voltage at one end of the capacitor, and the two ends of the operational amplifier are connected with a capacitor and a switch in parallel, wherein the optimal working interval of the operational amplifier is between the electron multiplier and the Faraday current amplifier.
As preferable: the Faraday cup and the electron multiplier are combined, and isotopes with different contents are detected by using different sensitivity intervals, namely when ions are counted>10 6 When cps, adopting Faraday cup current amplifying mode to detect ions; when the ion count is 10 5 ～10 6 When cps, adopting Faraday cup capacitance amplifying mode to detect ions; when ion counting<10 5 At cps, ion detection is performed using the pulse counting mode of the electron multiplier.
As preferable: the sample table is provided with a sample target, the target support 3 is made of stainless steel, the target surface 2 is made of epoxy resin, the surface of the target surface 2 is flush with the target support 3, the peak valley value of the flatness of the target surface 2 is less than 20 mu m, and the standard sample and all samples to be analyzed are distributed in the diameter range of 10 mm.
As preferable: adopting an alkali metal Cs+ ion source with the intensity of 10-15nA to excite electronegative secondary particles, and adopting a low-energy electron beam generated by an electron gun to neutralize primary ions on the surface of a sample target and eliminate charge accumulation; firstly, measuring 3-4 standard samples of oxygen and silicon isotopes, and when the error is within 0.3 per mill, starting to test the oxygen and silicon isotopes according to a period, wherein the time for acquiring oxygen isotope data and silicon isotope data is 1: and 2, collecting at least 6 groups of oxygen and silicon, and adopting a sequential cross mode to enable analysis conditions to be as close as possible.
The beneficial effects of the invention are as follows:
the invention provides an in-situ combined measurement analysis method for silicon oxygen isotope micro-regions of an ion probe, which utilizes a time slicing method, and the technologies of high stable magnetic field control, repeated positioning of multiple receivers, dynamic adjustment of amplifier gain and baseline, novel Faraday cup amplifier, combined use of Faraday cup and electron multiplier and the like, adopts the same ion beam to bombard the same position, realizes in-situ analysis of micro-regions of the same position of Si and O elements for the first time, provides a new method for in-situ observation of Si-O isotope cooperative change rules in micrometer scale, and provides a new method for fine geochemistry research such as formation mechanism of a pre-chilly strip-shaped iron-containing construction cause and a silicon iron rhythm layer. The method can be used for the existing commercial mass spectrometer and has universality.
Drawings
FIG. 1 is a schematic diagram of a magnetic field high-precision control operation;
FIG. 2, schematic diagram of ion probe measurement Si, O isotope detector positions;
FIG. 3 is a diagram of a Faraday cup capacitance amplifying operation mode and a traditional mode;
FIG. 4, top view and cross-sectional view of a conventional standard sample target;
FIG. 5, top view and cross-sectional view of an improved sample target;
FIG. 6, schematic diagram of Si-O co-measurement sample target.
Reference numerals of fig. 4 and 5:
1. clamping springs;
2. a target surface;
3. a target holder.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the detailed description is presented by way of example only and is not intended to limit the invention.
The embodiment provides an ion probe silicon oxygen isotope micro-region in-situ joint detection analysis method, which divides an experimental analysis period T (21 minutes) of the ion probe into T 1 、T 2 And T m Three time slices (where t=t 1 +T m +T 2 ，T 1 For Si isotope analysis time, T 2 For O isotope analysis time, T m For magnetic field switching stabilization time), peak jump analysis is carried out between different experimental periods according to time slicing, a sample table is kept stationary in the whole period T of the period, and two isotopes of Si and O are analyzed at the same position by using the same ion beam, so that in-situ joint measurement analysis of Si and O isotope micro-areas is realized.
As at T 1 Periodic reception by LM and HM Faraday cups, respectively 28 Si and 30 after the Si signal and Si isotope analysis are completed, at T 2 The Faraday cup receiving is respectively utilized for LM, AA and HM in the period 16 O、 17 O、 18 O signal, magnetic field switching stabilization time is period T m 。
Where HM is a high mass number Faraday cup receiver, AA is an intermediate mass number Faraday cup receiver, and LM is a low mass number Faraday cup receiver.
The technical means utilized by the invention comprise: (1) a high stable magnetic field control method; (2) a multi-receiver repeat positioning method; (3) amplifier gain and baseline dynamic adjustment; (4) faraday cup novel amplifier technology; (5) the Faraday cup is combined with the electron multiplier; (6) and (5) establishing an experimental flow.
(1) High-stability magnetic field control method
When the Si and O isotopes are tested, the magnetic field is limited by the dispersion capacity of the magnetic field of the instrument, and the magnetic field needs to be rapidly switched from one state to the other state by adopting a peak-jump mode. The stability of the magnetic field directly affects the analytical accuracy of the instrument. The settling time and the fast switching of the magnetic field are contradictory. The switching time of the ion probe magnetic field from O to Si to O is less than 2s each time, and the magnetic field switching speed requirement during sample analysis is met. To achieve high precision analysis of Si, O isotopes (better than 0.3%o) it is necessary to increase the low mass number static magnetic field stability from the current 30ppm to 10ppm (Δm/M,20 mins).
Because the relation between the magnetic field intensity and the current of the ion probe magnet has no definite mathematical model, the original magnetic field control system of the instrument is driven by a standard linear function and relates to tuned proportional, integral and differential components so as to reduce overshoot and stabilization time to the greatest extent. The system can control large input steps, but the control parameters cannot handle ppm level adjustment, at which the response of the magnetic field strength to control is different from the overall L/R impedance characteristics, thus nonlinear performance can lead to longer settling times of the magnetic field.
Aiming at the problems existing in the prior system, the invention provides an improved magnetic field control structure, 4 low magnetic field Hall detectors (measuring range 0-1000 Gasuss) are added on the basis of the prior 4 standard Hall detectors (measuring range 0-5000 Gasuss), a fuzzy logic control (fuzzy logic control) algorithm is adopted to generate a nonlinear transfer function corresponding to a magnetic field and a control current, and control parameters of the nonlinear transfer function are adjusted to adapt to step changes of different levels, and the stabilizing time of all incremental changes is reduced to the greatest extent. The system adopts a complete digital signal processing method to control a loop, and eliminates the drift of a digital-to-analog converter in the original magnetic field control system. As shown in fig. 1, detection may be performed by a switch option using a standard or low field probe. Two control algorithms in the magnetic field control system can handle different situations in the control process. The digital, proportional, and derivative control modules are intended to provide a fast initial response to large step changes for the magnetic field control system, but not close loop errors at small values. The fuzzy logic controller aims to minimize field noise with errors below about 1400 milligauss and control the loop after the PD module reduces the errors to within this range. Alternatively, the PD controller may be turned off and the fuzzy logic controller may fully control the entire system to raise the low mass number field stability to 10ppm.
(2) Multi-receiver repeated positioning method
When the ion probe is used for peak-jump measurement of Si and O isotopes, a plurality of Faraday receiving cups are needed to be used each time, a program-controlled amplifier is connected behind each receiving cup, and each Faraday receiving cup is fixed on an independent two-dimensional motion table and can move freely in the X, Y direction. Fast switching (Si, O) between the two test states is required in each test cycle.
Si isotope test state, namely, when the corresponding position P1 (x, y) and P2 (x, y) of the cup are received, the detection signal and peak shape obtained by the receiver are optimal.
O isotope test status: the receiver obtains the best detection signal and peak shape when the corresponding position P1 x, y, P2 x, y, and P3 x, y of the receiving cup.
The positions of the Si and O elements need to be continuously switched according to the period during analysis, and the position error of the receiver can influence the peak shape and the signal intensity of the Si and O elements, thereby influencing the measurement accuracy.
The invention introduces a piezoelectric ceramic element driving receiver, and utilizes the expansion characteristic of ceramic after being electrified to lead the guide rail to creep and form relative motion. Each faraday cup can be driven by the piezoelectric ceramic element to move in the X or Y direction to find the best focusing plane (fig. 2). The piezoelectric ceramic element and the grating ruler are preset in the crossed roller guide rail to drive the high-resolution movement (minimum step length of 50 nm) of the receiver, and the peak shape and the peak top shape of the spectrum of the received signal are combined to judge whether the receiver reaches the optimal receiving position, namely the ion focusing plane. Meanwhile, the control program can send an instruction to drive the receiver to move until the peak shape of the spectrum peak of the received signal meets the requirement, so that the high-precision repeated positioning of the position of the receiver is realized.
(3) Amplifier gain and baseline dynamics adjustment
Si @ during ion probe analysis 28 Si、 29 Si、 30 Si relative abundance is 0.92223, 0.04685, 0.03092O #, respectively 16 O、 17 O、 18 The relative abundance of O is 0.99757, 0.00038 and 0.00205) isotope abundance difference can reach 2625 times at maximum, the signal-to-noise ratio of the fixed gain amplifying circuit can not meet the requirement of high-precision measurement, the invention automatically adjusts the program-controlled amplifier connected at the rear end of the Faraday cup receiver through control software, and dynamically adjusts the background according to the feedback signalAnd the noise baseline and the spectrum peak processing technology are combined to realize automatic tuning in the high-precision detection process of Si and O isotopes.
The existing control software can only adjust the signal size of the amplifier through controlling the relay to adjust the resistor connected with the rear end of the Faraday cup, and can not dynamically adjust the noise floor according to the feedback signal. The control software is written by LabVIEW graphical language, and controls the relay connected to the rear end of the Faraday cup by controlling the PCIO interface card of the computer slot, thereby realizing the Faraday cup 10 10 、10 11 、10 12 And when the omega range is switched, the gate valve at the inlet of the multiple receivers can be automatically closed according to user setting, and the background noise baseline of each receiver is dynamically adjusted according to the received signals.
(4) Faraday cup capacitance amplifier technology
Measuring large differences in abundance 18 O, and weaker ion beam current 30 When Si is used, dead time exists in an electron multiplier (SEM) (the SEM is influenced by the dead time to leak ions), the background noise of a Faraday Cup (FC) current amplifier is large, and the isotope measurement precision is restricted. The invention introduces a capacitive amplifier (namely, faraday cup capacitive amplifier mode) on a Faraday Cup (FC) current amplifier (namely, faraday cup current amplifying working mode), and effectively solves the problem (shown in figure 3). The Faraday cup capacitance amplifier mode optimum operating range is between that of a traditional electron multiplier (< 10) 5 cps) and faraday current amplifiers (> 10) 6 cps of 10 12 /10 11 /10 10 Omega high resistance), exactly compensates for the 10 th of the two methods 5 -10 6 The detection accuracy of the cps interval is insufficient and the signal-to-noise ratio is low.
The invention relates to a Faraday cup current amplifying mode and a Faraday cup capacitance amplifier mode which coexist, and a traditional Faraday cup receiver is referred to as a Faraday cup current amplifying mode, and the principle is that a high resistance, such as 10, is connected behind the Faraday cup 11 And omega, the current generates voltage at the resistor end through high resistance, and the intensity information of ions can be obtained by measuring the voltage. The invention uses a capacitor to replace the resistor connected with the rear end of the original Faraday cup receiver (namelyA faraday cup capacitance amplifier mode) to operate in the faraday cup capacitance amplifier mode, and accurate measurement of the ionic strength is achieved by measuring the voltage at one end of the capacitor. Realizing ion at 10 5 cps-10 6 High-precision measurement of cps interval is difficult. The ion beam intensity is 10 5 cps-10 6 During the cps interval, the electron multiplier is influenced by dead time to leak ions, and the Faraday cup current amplifier is limited by self noise, so that accurate measurement of weak ion signals is difficult to realize.
(5) Faraday Cup (FC) and electron multiplier (SEM) combination
In order to improve the dynamic range of the detector, the invention combines FC and SEM, and detects isotopes with different contents by using different sensitivity intervals, namely when the ions are counted>10 6 When cps, adopting an FC current amplification mode to detect ions; when the ion count is 10 5 ～10 6 When cps, adopting an FC capacitance amplification mode to detect ions; when ion counting<10 5 And when cps are used, ion detection is carried out by adopting a pulse counting mode of SEM, and the combination mode utilizes the optimal detection interval of each detector to improve the analysis precision of the instrument.
(6) Si-O isotope joint test experimental procedure.
Target holder 3 improvement: the standard sample target is cylindrical, the diameter of the bottom surface is 25 mm, a stainless steel target holder 3 is required for fixing the target when the ion probe measurement is carried out, and a metal outer ring (shown in fig. 4) with a height difference of 250 μm and a protruding part is arranged on the surface of the stainless steel target holder and the gold-plated resin. In order to eliminate isotope fractionation effect caused by the difference of the outer ring of the stainless steel target holder 3 and the resin material of the sample target, the target holder 3 is redesigned (fig. 5), the stainless steel target holder 3 is horizontally and horizontally cut off by about 45 degrees to form a height difference of 250 μm (see the shadow part of fig. 5 in particular), the epoxy resin target surface is flush with the stainless steel target holder 3, so that the sample target surface 2 is a complete resin surface for primary incident ions (incidence of 45 degrees in the horizontal direction of the primary ion beam) and secondary ion extraction lenses (in the vertical direction of the target surface 2), thereby being beneficial to reducing distortion of a secondary ion extraction electric field and reducing quality fractionation brought by the traditional sample target.
And (3) target making: standard samples on the sample target are required to meet the correction requirements of two isotopes of O and Si simultaneously; the peak-valley value of the flatness of the target surface 2 is less than 20 mu m; the standard sample and all samples to be analyzed are distributed in the diameter range of 10 mm (the standard target is directly 25 mm), and the probability of deviation caused by isotope fractionation due to geometric effects can be effectively reduced by the layout, as shown in fig. 6.
And (3) on-machine analysis: by alkali metal Cs + The ion source has the intensity of 10-15nA, and excites electronegative secondary particles, and meanwhile, low-energy electron beams generated by an electron gun are adopted to neutralize primary ions on the surface of a sample target and eliminate charge accumulation; firstly, measuring O and Si isotopes of 3-4 standard samples, and when the error is within 0.3 per mill, starting to test the O and Si isotopes according to a period, wherein the time for collecting O isotope data and Si isotope data is 1:2, O and Si are collected to be not less than 6 groups, and the analysis conditions are as close as possible by adopting a sequential cross mode.
By adopting the technical scheme disclosed by the invention, the following beneficial effects are obtained: the method solves the technical problem of combined measurement of Si and O isotopes of an ion probe, establishes a high-precision Si and O isotope micro-region in-situ combined measurement analysis method, adopts the same ion beam to bombard the same position, truly realizes the micro-region in-situ analysis of Si and O two elements, and provides a new method and technical means for in-situ observation of Si and O isotope cooperative change rules in μm scale, research of the formation mechanism of a ferrosilicon rhythm layer, and fine geochemistry research of the state and evolution of early earth atmosphere and water ring and the like.
In the description of the present specification, the descriptions of the terms "one embodiment," "an implementation," "an example," "a particular example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Further, one skilled in the art can engage and combine the different embodiments or examples described in this specification.
While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.
Claims (9)
1. An ion probe silicon oxygen isotope micro-region in-situ joint detection analysis method is characterized in that: dividing an experimental analysis period T of the ion probe into three time slices, carrying out peak jump analysis among different experimental periods according to the time slices, keeping a sample table stationary in the whole analysis period T, bombarding a sample target at the same position by using the same ion beam, and sequentially analyzing two isotopes of Si and O to realize in-situ joint measurement analysis of micro-areas of the two isotopes of Si and O;
the experimental analysis period T is divided into T 1 、T 2 And T m Three time slices, where t=t 1 +T m +T 2 ，T 1 Is S i Isotope analysis time, T 2 For O isotope analysis time, T m Switching the stabilization time for the magnetic field;
in the peak jump analysis process of the mass spectrometer, a high-stability magnetic field control method is adopted to change a magnetic field control structure, 4 low-magnetic field Hall detectors are added on the basis of the original 4 standard Hall detectors, a fuzzy logic control algorithm is adopted to generate a nonlinear transfer function corresponding to a magnetic field and control current, and control parameters of the nonlinear transfer function are adjusted to adapt to step changes of different levels, and the stability time of all incremental changes is reduced to the greatest extent.
2. The method for in-situ simultaneous detection and analysis of silicon oxygen isotope microdomains of an ion probe according to claim 1, wherein the method comprises the following steps: in the bombardment process, a multi-receiver repeated positioning method is adopted, a piezoelectric ceramic element is introduced to drive a receiver, the expansion characteristic of piezoelectric ceramic after being electrified is utilized to enable a guide rail to creep with the guide rail, so that relative motion is formed, the piezoelectric ceramic element and a grating ruler are preset in a crossed roller guide rail to drive high-resolution movement of the receiver, the peak top shape of a spectrum peak of a received signal is combined to judge whether the receiver reaches an optimal receiving position, and meanwhile, the receiver is driven to move by sending an instruction until the peak shape of the spectrum peak of the received signal meets the requirement, so that high-precision repeated positioning of the receiver position is realized;
when the ion probe is used for measuring Si and O isotopes in a peak-jump manner, a plurality of Faraday receiving cups are needed to be used each time, a program-controlled amplifier is connected behind each receiving cup, each Faraday receiving cup is fixed on an independent two-dimensional motion table and can freely move in the X, Y direction, and Si and O need to be rapidly switched between two testing states in each testing period.
3. The method for in-situ simultaneous detection and analysis of silicon oxygen isotope microdomains of an ion probe according to claim 1, wherein the method comprises the following steps: the experimental analysis period T is 21 minutes and is divided into T 1 、T 2 And T m Three time slices, where t=t 1 +T m +T 2 ，T 1 For Si isotope analysis time, T 2 For O isotope analysis time, T m For the magnetic field switching stabilization time, at T 1 Periodic reception by LM and HM Faraday cups, respectively 28 Si and 30 after the Si signal and Si isotope analysis are completed, at T 2 The Faraday cup receiving is respectively utilized for LM, AA and HM in the period 16 O、 17 O、 18 O signal, magnetic field switching stabilization time is period T m ；
Where HM is a high mass number Faraday cup receiver, AA is an intermediate mass number Faraday cup receiver, and LM is a low mass number Faraday cup receiver.
4. The method for in-situ simultaneous detection and analysis of silicon oxygen isotope microdomains of an ion probe according to claim 1, wherein the method comprises the following steps: during the analysis of the ion probe, the program controlled amplifier connected to the rear end of the Faraday cup is automatically regulated by control software, the background noise base line is dynamically regulated according to the feedback signal, and the automatic tuning in the high-precision detection process of Si and O isotopes is realized by combining a spectral peak processing technology.
5. The method for in-situ simultaneous detection and analysis of silicon oxygen isotope microdomains of an ion probe according to claim 4, wherein the method comprises the following steps: the control software is written by LabVIEW graphical language, and the control software controls a relay connected to the rear end of the Faraday cup by controlling a PCII/O interface card of a computer slot to realize the Faraday cup 10 10 、10 11 、10 12 And switching of omega range, and simultaneously automatically closing gate valves at inlets of the multiple receivers according to user setting, and dynamically adjusting background noise baselines of the multiple receivers according to feedback signals.
6. The method for in-situ simultaneous detection and analysis of silicon oxygen isotope microdomains of an ion probe according to claim 3, wherein the method comprises the following steps: the resistor connected with the rear end of the Faraday cup receiver is replaced by a capacitor, so that the Faraday cup receiver works in a Faraday cup capacitor amplifier mode, the accurate measurement of the ion intensity is realized by measuring the voltage at one end of the capacitor, and the two ends of the operational amplifier are connected with a capacitor and a switch which are connected in parallel, wherein the optimal working interval of the operational amplifier is between the electron multiplier and the Faraday current amplifier.
7. The method for in-situ simultaneous detection and analysis of silicon oxygen isotope microdomains of an ion probe according to claim 3, wherein the method comprises the following steps: the Faraday cup and the electron multiplier are combined, and isotopes with different contents are detected by using different sensitivity intervals, namely when ions are counted>10 6 When cps, adopting the Faraday cup current amplification mode to detect ions; when the ion count is 10 5 ～10 6 When cps, adopting the Faraday cup capacitance amplification mode to detect ions; when ion counting<10 5 And (3) at cps, adopting a pulse counting mode of the electron multiplier to detect ions.
8. An ion probe silicon oxygen isotope micro-region in situ simultaneous detection and analysis method as claimed in any one of claims 1-7, wherein: the sample bench is provided with a sample target, the target support (3) is made of stainless steel, the target surface (2) is made of epoxy resin, the surface of the target surface (2) is flush with the target support (3), the flatness peak valley value of the target surface (2) is less than 20 mu m, and the standard sample and all samples to be analyzed are distributed in the diameter range of 10 mm.
9. An ion probe silicon oxygen isotope micro-region in situ simultaneous detection and analysis method as claimed in any one of claims 1-7, wherein: adopting an alkali metal Cs+ ion source with the intensity of 10-15nA to excite electronegative secondary particles, and adopting a low-energy electron beam generated by an electron gun to neutralize primary ions on the surface of a sample target and eliminate charge accumulation; firstly, measuring 3-4 standard samples of oxygen and silicon isotopes, and when the error is within 0.3 per mill, starting to test the oxygen and silicon isotopes according to a period, wherein the time for acquiring oxygen isotope data and silicon isotope data is 1: and 2, collecting at least 6 groups of oxygen and silicon, and adopting a sequential cross mode to enable analysis conditions to be as close as possible.
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