Method and device for vacuum ultraviolet laser cleaning first mirror of tokamak

Abstract

The invention discloses a method and a device for cleaning a tokamak first mirror by vacuum ultraviolet laser. A dust impurity deposit layer on the first mirror is cleaned by adopting a laser ablation method; through controlling the output energy of a laser device, the energy density of an excimer laser bundle on the surface of a first mirror surface is at a cleaning threshold of the impurity deposition layer and the damages threshold of first mirror metal, and the first mirror metal material can not be damaged when the impurity is cleaned simultaneously. A laser with 193nm wavelength is adopted for the method and the device for cleaning the tokamak first mirror by the vacuum ultraviolet laser, in the mutual effect process of the laser and the material, the ablation effect is less, the surface uniformity is good, the dust is cleaned, and the effect is ideal.

Description

technical field [0001] The invention relates to the field of magnetic confinement fusion devices. During the operation of the magnetic confinement fusion device, some impurities are easily deposited on the surface of the first mirror to form a dust impurity layer, which affects the normal operation of optical diagnostic equipment. In particular, the invention relates to a method and equipment for quickly removing the dust impurity layer deposited on the surface of the first mirror of the Tokamak and restoring the reflectivity of the mirror without introducing new impurities. Background technique [0002] In the study of magnetic confinement fusion, ultraviolet, visible light, infrared and other diagnostic systems will observe the plasma through the first mirror. The mirrors used for these plasma diagnosis must be installed in the vacuum chamber and directly face the plasma. Optical diagnostics require the mirror to have a relatively wide viewing angle, so the first mirror ha...

AI Technical Summary

Problems solved by technology

However, the application of these cleaning techniques is very limited during the cleaning of the contaminated first mirror in the magnetic confinement fusion experiment.

During the cleaning process of the mechanical cleaning method, it is easy to produce scratches on the surface of the first mirror sample. It can be observed through atomic force microscopy and other means that the depth of these scratches may reach tens of nanometers. This damage is obviously irreversible. The cleaning efficiency of some special-shaped first-mirror samples is even less ideal

Chemical cleaning and ultrasonic cleaning will more or less introduce new impurities, and the cleaning effect is not ideal. Due to the limitations of the method itself, these two cleaning methods are not locally controllable during the cleaning process

When the nuclear fusion device is running, the temperature in the cavity is very high. The impurities introduced by the chemical cleaning method and the ultrasonic cleaning method are easy to evaporate, and new impurities are introduced into the discharge chamber of the entire controllable nuclear fusion device, which makes the already complicated optical analysis. become more difficult, and in severe cases may affect the operation of the entire device

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