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The Research On The Rapid Leak Detection Technology Of The Vacuum Electronic Device Based On TDLAS

Posted on:2017-04-06Degree:MasterType:Thesis
Country:ChinaCandidate:P TianFull Text:PDF
GTID:2348330509460323Subject:Microelectronics and Solid State Electronics
Abstract/Summary:PDF Full Text Request
The Vacuum Electronic Device includes the electron tube such as the stabilize tube,the super high-frequency tube and the microwave tube such as the klystron, the magnetron,which have been widely used in the field of Semiconductor, Communication, Rader,Navigation, Computer, Medical Diagnosis etc. The vacuum degree of the vacuum working environment is an important parameter to identify the quality of the device at its working state. In order to ensure the stability of the electronic vacuum device in the long-term working period, it is necessary to detect the leak degree of the device. Study on the rapid,non-contactable on-line leak detection of the vacuum electronic device has been of great importance both on the theoretical and the engineering aspects.In the light of the vacuum electronic device with a transparent window working in the open air, this paper referred to a kind of method called Tunable Diode Laser Absorption Spectroscopy(TDLAS) to measure the leak degree. As an optical non-contactable gas detection method, TDLAS was famous for its high precision, quick response, stable performance, etc. Firstly, the principle of the TDLAS applying to the measurement of gas concentration and temperature, velocity of the flow field trace were introduced and the MATLAB Simulink simulation model for the vacuum degree measurement was established;Secondly, the vacuum degree detection system was designed using the tunable diode laser wavelength near 763 nm, aimed for the measurement object of O2, consisting with a sealed cavity with a lens for measuring medium was arranged. Finally, with the using of the wavelength modulation(WMS) method of the TDLAS technology, the research managed to find the proper absorption peak near 763.426 nm for the gas of O2, optimized modulation parameters, and studied the relationship between the WMS phase lock output signal--the key parameters of the second harmonic absorption line and the various vacuum negative pressure with the combination of the simulation and the experiment result. In conclusion,the study used the second harmonic absorption line peak value as the scalar measurement for the vacuum degree detecting and a polynomial fitting curve was given. The precision of the vacuum degree detection system has reached to the minimum limit of 0.1 atm, with 74 Pa of the detection definition, which meets the requirement of the rapid leak detectionapplying to the vacuum electronic device nicely.The result of the research in this paper proved the feasibility to detect the leak degree with the application of TDLAS technology rapidly, which not only provided a proper method to the non-involved online detection of vacuum degree for the vacuum device, but also provided a new idea in the field of pressure detection for the TDLAS measurement.
Keywords/Search Tags:Vacuum Electronic Device, Non-contactable Leak Detection, Tunable diode absorption spectroscopy, Wavelength modulation
PDF Full Text Request
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