CN102128985B - Method for testing conductivity of medium material - Google Patents
Method for testing conductivity of medium material Download PDFInfo
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- CN102128985B CN102128985B CN 201010624606 CN201010624606A CN102128985B CN 102128985 B CN102128985 B CN 102128985B CN 201010624606 CN201010624606 CN 201010624606 CN 201010624606 A CN201010624606 A CN 201010624606A CN 102128985 B CN102128985 B CN 102128985B
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Abstract
The invention discloses a method for testing conductivity of medium material, wherein the method comprises the following steps of: positioning an electric potential probe at a zero electric potential position above a sample after the preparation before testing is finished; confirming the placing position of the sample, confirming the position coordinate of an electric potential measuring point by a probe driving mechanism, then closing a vacuum jar, turning on the power of an electric gun, and performing electronic irradiation to the sample via a Faraday cut test; quickly descending an electric potential meter probe to the front surface of the sample every 10 minutes to perform inducted non-contact measurement, wherein the data measured by a micro galvanometer and the electric potential probe is waved between negative 0.5% and positive 0.5%, then the charge of the sample is regarded as saturation; turning off the electric gun, attenuating the similar process via a tapping index form in the sample interior electric charge Q and measuring the electric potential decay process of the sample; in a word, the attenuation relationship of the surface electric potential of the sample along time is measured by a surface electric potential probe, and the conductivity of the sample can be calculated according to the sample surface attenuated electric potential at different time. The conductivity testing equipment in the invention can be applied to hazard assessment of deep charging, and also can provide valuable engineering data for the protection of deep charging or discharging.
Description
Technical field
The present invention relates to a kind of dielectric material charge-discharge test method, particularly dielectric material Surface potential measurement system under a kind of vacuum environment belongs to field tests.
Background technology
For alleviating throw-weight and satisfying the performance requirements such as spacecraft electricity, heat, mechanics, spacecraft will be used a large amount of organic media materials.In the space radiation environment, high energy particle, plasma easily inner at the dielectric material of spacecraft periphery or pass the spacecraft shileding layer within it the dielectric material of section deposit.Electric discharge phenomena can occur when the surperficial electric field with miscellaneous part potential difference (PD) or deposited charge generation on every side of these dielectric materials surpasses certain threshold value, high-energy discharge then can directly cause responsive electronic devices and components to puncture or organic media punctures, this will disturb the normal operation of electronic device on the spacecraft, when serious spacecraft is broken down.
Conductivity of medium material is the important materials parameter that affects the satellite charging current potential, and it has determined the speed of charge leakage in the dielectric material charging process.At present, the measurement of China's conductivity of medium material generally adopts three-electrode method to carry out.Because star is minimum with the conductivity of dielectric material, usually need to adopt special weak current testing apparatus to measure.But under the impact of the factors such as sample environmental baseline of living in (such as temperature, humidity, vacuum tightness), sample state (such as purity, surface cleanness degree, thickness of sample and size), test condition (as applying voltage swing, test duration and jig Design), this measurement result can produce along with the difference of test condition the variation of 2 orders of magnitude.Therefore stable in the urgent need to developing, be suitable for the method and apparatus of the sample conductivity of test space Issues on Static Electrification reliably.
Conventional conductivity measuring method also not exclusively is suitable for the spatial charging environment, the main cause that conventional method is unsuitable for space condition has: (1) charge injection is different, formed charged particles densimetric curve and electric field also have in essence different: conventional three-electrode method voltage provides by power supply, and the dielectric charge surface potential to be charge injection form; (2) electrode number is different: conventional three-electrode method has electrode in the medium both sides, and charged in the medium side is only arranged is electrode, and opposite side then is the charge injection face; (3) research purpose is different: conventional three-electrode method conductivity measurement is relevant with the loss of power in medium, and does not consider storage time and quantity behind the charge injection; (4) leakage current measurement asynchronism(-nization): the Measuring Time of conventional three-electrode method or reading duration are several minutes, and space medium charging or damped cycle can reach the several months long, and the variation of dielectric conductance rate just can display in the long period.
Summary of the invention
The object of the invention provides a kind of dielectric material charge-discharge test method, and the method for testing of conductivity is selected the charge decay method among the present invention---and utilize electronic injection, contactless surface potential measurement method to obtain conductivity of medium material.Low-energy electron rifle irradiating medium sample makes its surface reach certain current potential (usually approaching the dangerous current potential of discharge) in the utilization, stops afterwards irradiation and makes Sample storage at vacuum chamber.
Testing apparatus among the present invention comprises vacuum system, charge-discharge system, potential test system.Wherein vacuum system comprises vacuum tank, mechanical pump, diffusion pump, multistage sliding vane rotary pump, valve, sealing pipeline and worktable; Charge-discharge system is comprised of electron gun and sample installation system; The potential test system comprises pot and microgalvanometer.
The annexation of native system is: vacuum tank is placed on the worktable, be connected with mechanical pump through flapper valve by one road sealing pipeline, be connected with diffusion pump through flapper valve by another road sealing pipeline, mechanical pump, lobe pump, diffusion pump form the unit of bleeding in the vacuum system; Electron gun is positioned at place, axis, vacuum chamber top; Sample is installed on the copper coin of center of vacuum chamber bottom, and copper coin is coaxial with electron gun, between sample and the copper coin with the isolation of block teflon; Vacuum meter is positioned at the top of vacuum tank inside, is in the optional position that does not affect other top components and parts; The charging potential of sample surfaces and decay current potential are tested by pot, and the line of electron gun is tested by Faraday cup, and the movement of pot and Faraday cup can be moved in the plane of two dimension by driving mechanisms control; Microgalvanometer is connected on the back electrode of sample, and main tested object is the Leakage Current of sample when charging.
This test macro workflow is:
The first step is prepared before the test, checks recirculated water, the circuit of the consumers such as vacuum system and electron gun, pot, microgalvanometer, the signal line of detector;
Second step carries out drying to sample and processes; Press the circuit connection among Fig. 1, the current potential probe is positioned at zero-potential point place, sample top; Determine the sample riding position, determine the position coordinates of potential measurement point with the probe driving mechanism.
Second step is closed vacuum tank, vacuumizes to make system vacuum to 5.4x10
-4Below the Pa, open the electron gun power supply, electron energy is set to 14Kev, makes sample by 2.0nA/cm with the Faraday cup test
2Electron irradiation, the charging potential of sample surfaces cooperates pot probe TREK 3450E to test by pot TREK 341HV.Every 10 minutes the pot probe is dropped rapidly to apart from sample front surface 2cm place, carries out the induction type non-cpntact measurement; The data that microgalvanometer and current potential probe record think namely that in positive and negative 0.5% interior fluctuation the sample charging is saturated, close afterwards electron gun.
The 3rd step, after closing electron gun, utilize releasing of sample interior charge Q to be the exponential form similar process that decays, measure the potential decay process of sample, be specially: every 30 minutes probe is dropped rapidly to apart from sample front surface 2cm place, carry out the induction type non-cpntact measurement, with the data typing testing software that records, the conductivity of calculation sample.Specific formula for calculation is:
τ=ερ
Wherein: Vs-surface voltage, Vs0-initial surface charging voltage, ρ-body resistivity, ε-specific inductive capacity, t-die-away time, τ-time attenuation constant;
In a word, utilize surface potential probe measurement sample surfaces current potential attenuation relation in time, can extrapolate the conductivity of sample according to the sample surfaces decay current potential of the different time that measures.
In the 4th step, after off-test, the power supply of closing test device is opened gas valve, opens vacuum tank, takes out test specimen.
Advantage of the present invention is: the dielectric conductance rate is more high more to be unfavorable for releasing of deposited charge, if the electrical resistivity results that adopts classic method to measure is assessed the deep layer charging process of spacecraft component, with the deposited charge in the underestimation dielectric material, and then may underestimate discharge risk and cause unnecessary loss.This method of testing listed by table 1 and conventional test methodologies is used for testing the result of typical media material bodies resistivity, tables look-up apparent.The conductivity method of testing is suitable for deep layer charging hazard evaluation among the present invention, and valuable project data can be provided for the protection of deep layer charging and discharging effects.
The charge decay method---utilize electronic injection, contactless surface potential measurement method to obtain conductivity of medium material.This method of testing high precision, highly reliable, it is more suitable for the measurement of conductivity of medium material under the spatial charging environment.Proving installation of the present invention has improved experiment automatized degree, control accuracy, test efficiency.The method is in the ordinary course of things than the high one or more magnitude of traditional method.
The comparison of table one method of testing of the present invention and traditional test dielectric material body resistivity test result
Description of drawings
The test macro of a kind of conductivity of medium material of Fig. 1-the present invention is seen figure
Among the figure: the multistage sliding vane rotary pump of 1-, 2-diffusion pump, 3-mechanical pump, 4-vacuum valve, 5-vacuum meter, 6-electron gun, 7-pot valve, 8-Ferrari cup, 9-pot, 10-driving mechanism, 11-sample, 12-teflon insulation piece, 13-copper coin, 14-microgalvanometer, 15-flapper valve A, 16-flapper valve B
Fig. 2-25 μ m single face the scheme of installation of Kapton film in when test of aluminizing
Embodiment
Testing apparatus among the present invention comprises vacuum system, charge-discharge system, potential test system.Wherein vacuum system comprises vacuum tank, mechanical pump 3, diffusion pump 2, multistage sliding vane rotary pump 1, valve, sealing pipeline and worktable; Charge-discharge system is comprised of electron gun 6 and sample 11 installation systems; The potential test system comprises pot 9 and microgalvanometer 14, is placed with vacuum valve 4, vacuum meter 5 in the vacuum tank.
The annexation of native system is: vacuum tank is placed on the worktable, be connected with mechanical pump through flapper valve A15 by one road sealing pipeline, are connected connection by another road sealing pipeline with diffusion pump through flapper valve B16, the unit of bleeding that mechanical pump 3, multistage sliding vane rotary pump 1, diffusion pump 2 form in the vacuum systems; Electron gun 6 is positioned at place, axis, vacuum chamber top; Sample 11 is installed on the copper coin 13 of center of vacuum chamber bottom, and copper coin 13 is coaxial with electron gun 6, between sample 11 and the copper coin 13 with 12 isolation of teflon insulation piece; Vacuum meter 5 is positioned at the top of vacuum tank inside, is in the optional position that does not affect other top components and parts; The charging potential on sample 11 surfaces and decay current potential are by pot 9 tests, and the line of electron gun 6 is by Faraday cup 8 tests, and the movement of pot 9 and Faraday cup 8 can be moved in the plane of two dimension by driving mechanism 10 controls; Microgalvanometer 14 is connected on the back electrode of sample 11, and main tested object is the Leakage Current of sample when charging.
This test macro workflow is:
The first step is prepared before the test, checks recirculated water, the circuit of the consumers such as vacuum system and electron gun, pot, microgalvanometer, the signal line of detector;
Second step is at 80 ℃, the 25 μ m single faces Kapton film oven dry 2h that aluminizes; Press the circuit connection among Fig. 1, the current potential probe is positioned at zero-potential point place, sample top; Determine the sample riding position, determine the position coordinates of potential measurement point with the probe driving mechanism.
Second step is closed vacuum tank, vacuumizes to make system vacuum to 5.4x10
-4Below the Pa, open the electron gun power supply, electron energy is set to 14Kev, makes sample by 2.0nA/cm with the Faraday cup test
2Electron irradiation, the charging potential of sample surfaces cooperates pot probe TREK 3450E to test by pot TREK 341HV.Every 10 minutes the pot probe is dropped rapidly to apart from sample front surface 2cm place, carries out the induction type non-cpntact measurement; The Leakage Current of this sample is to think that the sample charging is saturated at 23 ± 0.2pA, charging potential at 3250 ± 50V, closes afterwards electron gun.
The 3rd the step, close electron gun after, every 30 minutes probe is dropped rapidly to apart from sample front surface 2cm place, carry out the induction type non-cpntact measurement, with the data typing testing software that records, the conductivity of calculation sample.
In the 4th step, after off-test, the power supply of closing test device is opened gas valve, opens vacuum tank, takes out test specimen.
25 μ m single faces are aluminized body resistivity result that the Kapton film records with conventional test methodologies 10
16(Ω cm), and the result who records with this method is 10
18About (Ω cm), if the electrical resistivity results that this explanation adopts classic method to measure is assessed the deep layer charging process of spacecraft component, with the deposited charge in the underestimation dielectric material, and the die-away time of deposited charge, and then may underestimate the discharge risk and caused unnecessary loss.
Claims (4)
1. dielectric material charge-discharge test method, its testing apparatus comprises vacuum system, charge-discharge system, potential test system; Wherein vacuum system comprises vacuum tank, mechanical pump, diffusion pump, multistage sliding vane rotary pump, valve, sealing pipeline and worktable; Charge-discharge system is comprised of electron gun and sample installation system; The potential test system comprises pot and microgalvanometer;
It is characterized in that:
Described vacuum tank is placed on the worktable, is connected with mechanical pump through flapper valve by one road sealing pipeline, is connected with diffusion pump through flapper valve by another road sealing pipeline, and mechanical pump, multistage sliding vane rotary pump, diffusion pump form the unit of bleeding in the vacuum system; Described electron gun is positioned at place, axis, vacuum chamber top; Described sample is installed on the copper coin of center of vacuum chamber bottom, and copper coin is coaxial with electron gun, between sample and the copper coin with the isolation of teflon insulation piece; Vacuum meter is positioned at the top of vacuum tank inside, is in the optional position that does not affect other top components and parts; The charging potential of sample surfaces and decay current potential are tested by pot, and the line of electron gun is tested by Faraday cup, and the movement of pot and Faraday cup can be moved in the plane of two dimension by driving mechanisms control; Microgalvanometer is connected on the back electrode of sample, and main tested object is the Leakage Current of sample when charging;
This test macro workflow is:
The first step is prepared before the test, checks recirculated water, the circuit of vacuum system and electron gun, pot, microgalvanometer consumer, the signal line of detector;
Second step is positioned at the current potential probe in zero-potential point place, sample top; Determine the sample riding position, determine the position coordinates of potential measurement point with the probe driving mechanism;
The 3rd goes on foot, and closes vacuum tank, vacuumizes to make system vacuum to 5.4x10
-4Below the Pa, open the electron gun power supply, electron energy is set to 14Kev, makes sample by 2.0nA/cm with the Faraday cup test
2Electron irradiation, the charging potential of sample surfaces cooperates pot probe TREK 3450E to carry out the induction type non-cpntact measurement by pot TREK 341HV; Until the sample charging is saturated, close afterwards electron gun;
The 4th step, close electron gun after, utilize releasing of sample interior charge Q to be the exponential form similar process that decays, measure the potential decay process of sample, and with the data typing testing software that records, the conductivity of calculation sample; Specific formula for calculation is:
T=ερ
Wherein: Vs-surface voltage, Vs0-initial surface charging voltage, ρ-body resistivity, ε-specific inductive capacity, t-die-away time, T-time attenuation constant;
In the 5th step, after off-test, the power supply of closing test device is opened gas valve, opens vacuum tank, takes out test specimen;
In a word, utilize surface potential probe measurement sample surfaces current potential attenuation relation in time, can extrapolate the conductivity of sample according to the sample surfaces decay current potential of the different time that measures.
2. a kind of dielectric material charge-discharge test method according to claim 1 is characterized in that: in step 3, every 10 minutes the pot probe is dropped rapidly to apart from sample front surface 2cm place, carries out the induction type non-cpntact measurement.
3. a kind of dielectric material charge-discharge test method according to claim 1 is characterized in that: in step 3, the data that microgalvanometer and current potential probe record think namely that in positive and negative 0.5% interior fluctuation the sample charging is saturated.
4. a kind of dielectric material charge-discharge test method according to claim 1, it is characterized in that: in step 4, every 30 minutes probe is dropped rapidly to apart from sample front surface 2cm place, carries out the induction type non-cpntact measurement, with the data typing testing software that records.
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Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0710848A1 (en) * | 1994-11-02 | 1996-05-08 | Alcatel Cable | Procedure for measuring the voltage decay and the electron mobility of a material |
JP3144378B2 (en) * | 1998-04-01 | 2001-03-12 | 日本電気株式会社 | Method for manufacturing solid-state imaging device |
CN101187683A (en) * | 2007-10-30 | 2008-05-28 | 电子科技大学 | Low consumption dielectric material high temperature complex dielectric constant test device and method |
CN101452020A (en) * | 2007-12-04 | 2009-06-10 | 北京卫星环境工程研究所 | In-situ measurement material surface resistivity method under vacuum environment |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH03144378A (en) * | 1989-10-31 | 1991-06-19 | Yokogawa Electric Corp | Resistance measuring apparatus by electron beam |
-
2010
- 2010-12-30 CN CN 201010624606 patent/CN102128985B/en active Active
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0710848A1 (en) * | 1994-11-02 | 1996-05-08 | Alcatel Cable | Procedure for measuring the voltage decay and the electron mobility of a material |
JP3144378B2 (en) * | 1998-04-01 | 2001-03-12 | 日本電気株式会社 | Method for manufacturing solid-state imaging device |
CN101187683A (en) * | 2007-10-30 | 2008-05-28 | 电子科技大学 | Low consumption dielectric material high temperature complex dielectric constant test device and method |
CN101452020A (en) * | 2007-12-04 | 2009-06-10 | 北京卫星环境工程研究所 | In-situ measurement material surface resistivity method under vacuum environment |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
TWI623759B (en) * | 2013-09-04 | 2018-05-11 | 克萊譚克公司 | Apparatus for measurement of current-voltage characteristics |
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