A method for leak detection of a vacuum system

Abstract

The application discloses a method for leak detection of a vacuum system, which utilizes the characteristic that oxidation of silver nanoparticles in an ozone atmosphere can cause attenuation of plasmonic resonance peaks, so as to realize leak detection of the vacuum system. The application provides a brand-new method for leak detection of the vacuum system, and can intuitively reflect the vacuum leak detection result.

Description

Technical Field

[0001] This invention belongs to the field of vacuum system leak detection, specifically relating to a method for leak detection of vacuum systems using the oxidation properties of silver nanoparticles in an ozone atmosphere. Background Technology

[0002] Leak detection in vacuum systems is a crucial step in ensuring that the system can effectively maintain the required vacuum state and prevent leaks that could lead to performance degradation and safety risks. It offers numerous advantages, including improved equipment safety, extended equipment lifespan, energy savings, and increased production efficiency. Traditional vacuum system leak detection methods include pneumatic leak detection, ammonia-sensitive paper leak detection, high-frequency spark leak detection, discharge tube leak detection, and helium mass spectrometry leak detection. Among these, pneumatic leak detection utilizes the pressure difference across the object being tested, using sound observation or soap bubble methods to locate leaks. This method is simple and low-cost, but its sensitivity is not high. Ammonia-sensitive paper leak detection involves filling the vacuum environment with ammonia gas and observing spots on a bromophenol blue-coated outer wall through sealing paper to pinpoint leak locations. Ammonia is readily available and inexpensive, but it is toxic and corrosive to metals such as copper and silver. High-frequency spark leak detection involves moving a high-frequency spark regularly along the surface of the glass vacuum system and observing the spark highlights to locate suspected leaks. The first method is only applicable to leak detection in vacuum systems made of glass. Discharge tube leak detection utilizes the residual air in the vacuum system to generate a rose-red glow discharge with the discharge tube connected to the system. This is combined with volatile hydrocarbons coated with gasoline or acetone, and the blue discharge area is observed to determine the leak location. This method can detect minute leaks and is simple to operate, but it carries safety risks and is limited by environmental conditions. The helium mass spectrometry leak detection method utilizes the diffusion characteristics of helium molecules in a vacuum. Helium is sprayed in a spray gun along the outer surface of the workpiece. When the spray reaches a leak in the workpiece's outer shell, the helium enters the workpiece through the leak and then flows into the helium mass spectrometer, thus detecting the leak. This method has extremely high sensitivity and can detect very small leaks, but helium is expensive. Therefore, when choosing a suitable leak detection method, it is necessary to comprehensively consider the vacuum system requirements and actual conditions.

[0003] However, vacuum systems come in various forms, and existing leak detection methods are often constrained by various conditions, failing to achieve their intended effects. Exploring new leak detection methods is of great significance for expanding the application scope of vacuum leak detection technology. Summary of the Invention

[0004] This invention provides a method for leak detection in vacuum systems, which aims to achieve the purpose of vacuum leak detection by utilizing the attenuation of isotropic resonance peaks of silver nanoparticles in an ozone atmosphere.

[0005] To achieve the objective, the technical solution adopted by this invention is as follows:

[0006] A method for leak detection in vacuum systems is characterized by utilizing the property that the oxidation of silver nanoparticles in an ozone atmosphere causes the attenuation of their plasmon resonance peak, thereby enabling leak detection in vacuum systems. Specifically, when a leak occurs in the vacuum system, silver nanoparticles are placed inside a vacuum chamber, the chamber is evacuated, and then oxygen is sprayed towards the suspected leak location while the vacuum chamber is illuminated by a light source. If oxygen enters the vacuum chamber, due to the pressure difference between the vacuum chamber and the outside environment, the oxygen will rapidly diffuse within the vacuum chamber and generate ozone under the illumination of the light source. Ozone has strong oxidizing properties; silver nanoparticles will rapidly oxidize in an ozone atmosphere, causing the attenuation of their plasmon resonance peak, which in turn leads to a significant change in their absorption spectrum. Therefore, the change in the absorption spectrum of the silver nanoparticles can be used to determine whether a leak has occurred at the spray location.

[0007] Furthermore, the light source includes ultraviolet light.

[0008] Furthermore, the absorption spectrum of Ag nanoparticles in the vacuum chamber was detected in real time using a spectrometer.

[0009] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0010] This invention uses oxygen as a leak detection gas, which is widely available, low in cost, and can directly reflect the degree of leakage in a vacuum system. Attached Figure Description

[0011] Figure 1 The images show the UV-Vis absorption spectra of Ag nanoparticles in different atmospheres in Example 1. Detailed Implementation

[0012] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples. The following content is merely illustrative and explanatory of the concept of the present invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, as long as they do not deviate from the inventive concept or exceed the scope defined by the claims, all of which should fall within the protection scope of the present invention.

[0013] Example 1

[0014] In this embodiment, silver nanoparticles are prepared on a glass substrate by vacuum evaporation coating. The nanoparticles are then placed on a sample holder in the vacuum chamber of a vacuum system, and oxygen is introduced to simulate air leakage in the vacuum chamber. At the same time, the absorption spectrum of the silver nanoparticles is detected in real time using a fiber optic spectrometer with an ultraviolet-enhanced xenon lamp light source.

[0015] Step 1: After ultrasonically cleaning the glass substrate, dry it for later use. Connect a molybdenum boat to the evaporation electrode of a vacuum thermal evaporation system. Add a silver wire to the molybdenum boat, place the glass substrate in the substrate holder, and evacuate the vacuum chamber to a pressure below 4 × 10⁻⁶. -4 Pa. Turn on the power supply to the silver evaporation electrode to prepare a 1 nm thick Ag nanoparticle film on a glass substrate.

[0016] Step 2: Take out the Ag-plated sample and place it on the sample holder in the vacuum chamber of the vacuum system.

[0017] Step 3: Evacuate the vacuum chamber to a high vacuum, then introduce oxygen at 100 sccm to simulate a vacuum system leak. At the same time, use a fiber optic spectrometer with an ultraviolet-enhanced xenon lamp as the light source to detect the absorption spectrum of Ag nanoparticles in real time.

[0018] Figure 1 The figures show the UV-Vis absorption spectra of silver nanoparticles in Example 1 under vacuum and ozone atmosphere. Ag nanoparticles exhibit localized surface plasmon resonance (LSPR) in the UV-Vis to near-infrared range, and silver oxide strongly dampens this effect. For Ag nanoparticles, oxidation in an ozone atmosphere leads to the formation of a silver oxide shell on their surface, causing a decrease in the intensity of the plasmon resonance peak. As can be seen from the figures, the absorption spectrum of Ag nanoparticles in a vacuum shows a distinct LSPR peak; however, in an ozone atmosphere, Ag nanoparticles are rapidly oxidized, the LSPR peak is strongly damped, and the absorption spectrum becomes a straight line. Therefore, this invention provides a feasible and low-cost method for detecting vacuum system leaks by utilizing the oxidation characteristics of Ag nanoparticles in an ozone atmosphere.

[0019] The above are merely exemplary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for leak detection of a vacuum system, characterized in that, The silver nanoparticles are oxidized in the ozone atmosphere, which causes the plasmon resonance peak to attenuate, so that the leak of the vacuum system is detected, and the specific steps are as follows: when the vacuum system leaks, silver nanoparticles are put into the vacuum chamber of the vacuum system, the vacuum chamber is vacuumized, and then the suspected leakage position is sprayed with oxygen, and the vacuum chamber is irradiated by a light source; if oxygen enters the vacuum chamber, ozone is generated under the irradiation of the light source, the silver nanoparticles are oxidized in the ozone atmosphere, which causes the plasmon resonance peak to attenuate, so that whether the leakage occurs at the spraying position can be judged through the change of the silver nanoparticle absorption spectrum.

2. A method for leak detection of a vacuum system according to claim 1, characterized in that: The light source comprises ultraviolet light.

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