Research on measuring method of pumping speed for miniature sputter ion pump

Geng, Jian; Wang, Xiaodong; Guo, Meiru; Zhang, Shiwei; Cheng, Yongjun; Li, Yongchun; Li, Haitao; Ren, Zhengyi

doi:10.1016/j.measurement.2022.110736

Cited by 3 publications

(1 citation statement)

References 30 publications

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“…An apparatus for studying characteristics of the water vapor conductance and water detection at low temperatures was developed based on the flowmeter method [19]. A flowmeter with constant conductance was used to provide a through-put within the range of 3 × 10 −9 -9 × 10 −6 Pa m 3 s −1 of the water vapor, and the system was installed in an incubator to cool by liquid nitrogen.…”

Section: Introductionmentioning

confidence: 99%

Study on the water detection using the flowmeter method at low temperatures

Geng

Wang

Ren

et al. 2023

Meas. Sci. Technol.

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To prepare for the lunar water exploration in the Chinese Lunar Exploration Project IV (CLEP), a new apparatus for studying characteristics of the water vapor conductance and water detection at low temperatures was built based on the flowmeter method, and the performance of the miniature time-of-flight mass spectrometer (TOF-MS) for water detection in the range -20 ~ 20 ℃ was measured. The through-put within the range of 3×10-9-9×10-6 Pa m3 s-1 was provided at temperatures in the range -60 ~ 20 ℃. The conductance of the orifice with a diameter of 21 microns for three gases (N2, Ar, and H2O) was measured at low temperatures. The diameter change of the metal orifice caused by the cold contraction in the molecular flow state is the main factor affecting the conductance, and the viscosity characteristic of gas in the viscous flow state is the main factor affecting the conductance. Therefore, the conductance of the orifice increases with the decreasing temperature when the through-put is high. In addition, the water vapor can be stably supplied by the orifice under low temperatures, and the conductance of water vapor through the orifice is measured through the on-line method and the time-ratio method. The adsorption rate and amount of water vapor on the metal surface increase with the decreasing temperature, hence the concentration of water molecules in the test dome significantly decreases as the temperature decreases. Finally, the through-put of water vapor of 8.75×10-8 Pa m3 s-1 was detected by the miniature TOF-MC at -20℃ on the apparatus.

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Section: Introductionmentioning

confidence: 99%

Study on the water detection using the flowmeter method at low temperatures

Geng

Wang

Ren

et al. 2023

Meas. Sci. Technol.

Self Cite

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A novel method measuring orifice conductance and testing time-of-flight mass spectrometer for water vapor–binary gas

Geng,

Wang,

Ren

et al. 2024

Meas. Sci. Technol.

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The miniature time-of-flight mass spectrometer (TOF-MS) is a crucial instrument for detecting water ice in Chinese Lunar Exploration Program (CLEP), so it is necessary to compare its detection results for pure water vapor and water vapor-binary gas (such as H2O-N2, H2O-CH4, and H2O-Ar) to evaluate its water detection performance. The throughput must be calculated using the measured conductance to test the miniature TOF-MS. According to the VΔp method, the pΔt method, whose uncertainty is less than 14.2%, is proposed to measure orifice conductance for water vapor-binary gas, and an apparatus was developed based on those two methods. The orifice conductance of four kinds of pure gases (N2, H2O, CH4, and Ar) was measured using those two methods separately, and the measurement results allowed to calculate the conductance of the water vapor-binary gas through the Equivalent Single Gas method. The conductance of the water vapor-binary gas was measured using the pΔt method, and the difference between the calculated and measured results is less than 7%. Hence, the measured conductance allows the miniature TOF-MS to be tested for the water vapor-binary gas. As throughput is from 10-9 to 10-6 Pa m3 s-1, the difference between the test signals of water vapor-binary gas and pure water vapor is less than 40%.

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Optimizing Ultra-High Vacuum Control in Electron Storage Rings Using Fuzzy Control and Estimation of Pumping Speed by Neural Networks with Molflow+

Seangsri

Wanglomklang

Khaewnak

et al. 2023

Systems

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This paper presents the design of a fuzzy-controller-based ultra-high vacuum pressure control system and its performance evaluation for a sputter-ion vacuum pump used in the electron storage ring at the Synchrotron Light Research Institute (Public Organization) in Thailand. The production of synchrotron light requires advanced vacuum technology to maintain stability and prevent interference of electrons in an ultra-high vacuum pressure environment of about 10−9 Torr. The presence of heat and gas rupture from the pipe wall can affect the quality of the light in that area. The institute currently uses a sputter-ion vacuum pump which is costly and requires significant effort to quickly reduce pressure increases in the area. Maintaining stable vacuum pressure throughout electron motion is essential in order to ensure the quality of the light. This research demonstrates a procedure for evaluating the performance of a sputter-ion vacuum pump using a mathematical model generated by a neural network and Molflow+ software. The model is used to estimate the pumping speed of the vacuum pump and to design a fuzzy control system for the ultra-high vacuum system. The study also includes a leakage rate check for the vacuum system.

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Research on measuring method of pumping speed for miniature sputter ion pump

Cited by 3 publications

References 30 publications

Study on the water detection using the flowmeter method at low temperatures

Study on the water detection using the flowmeter method at low temperatures

A novel method measuring orifice conductance and testing time-of-flight mass spectrometer for water vapor–binary gas

Optimizing Ultra-High Vacuum Control in Electron Storage Rings Using Fuzzy Control and Estimation of Pumping Speed by Neural Networks with Molflow+

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