Study On Implantation And Residency Characteristics Of Deuterium Glow Discharge To Tungsten Materials

In order to simulate the interaction process between the hydrogen isotope plasma and the first wall in the Tokamak device,a glow injection and thermal desorption experimental platform was independently designed,and a tungsten injection and residence experiment of deuterium glow discharge was carried out.With the help of glow discharge spectrometer(GDOES),quadrupole mass spectrometer(QMS)and other testing methods,the concentration-depth distribution of deuterium in tungsten material samples was analyzed,and the influence of deuterium glow discharge parameters on the implantation characteristics and dwell characteristics of tungsten materials was obtained.The main contents of the paper include:(1)An experimental platform for glow injection and thermal desorption was designed and constructed.It has laid the foundation for the experimental research on the deuterium implantation of the surface glow discharge of tungsten materials and the calibration experimental research of GDOES.(2)A quantitative analysis method of GDOES was established,and a GDOES calibration experiment was completed.The deuterium signal intensity-sputtering time spectrum measured by GDOES was converted into a concentration-depth spectrum.(3)The effects of injection parameters such as deuterium pressure,injection bias,injection time and tungsten sample temperature on the concentration-depth distribution of deuterium in tungsten were investigated.The experimental results show that the surface concentration of tungsten increases with the increase of deuterium pressure;When the deuterium pressure is 45Pa～170Pa,the injection depth and total injection amount of deuterium in the tungsten sample increase with the increase of deuterium pressure;When the deuterium pressure is increased to 230 Pa,the amount of deuterium injection is reduced.The surface concentration of deuterium increases with increasing injection bias and the injection depth increases with the increase of injection bias;the total amount of injection increases with the increase of bias voltage.The concentration of deuterium on the surface of tungsten did not change significantly with the increase of injection time.The surface deuterium concentration of each tungsten sample was approximately the same;As the injection time increases,the total amount of niobium in the tungsten sample increases,and it gradually becomes saturated at a certain depth;After the injection time exceeded 60 min,the depth of implantation does not change any more.As the temperature of the tungsten sample increases,the deuterium concentration on the surface of the tungsten sample increases significantly after glow injection;the deuterium injection depth also increases with the increase of the sample temperature.As the temperature of the sample increases,the total content of deuterium in the tungsten increases.(4)Analysis of the diffusion and surface dissolution characteristics of deuterium in tungsten.Establish a diffusion model of deuterium in tungsten material and obtain a diffusion equation according to the boundary conditions.The measured diffusion data of the concentration-depth distribution of deuterium in tungsten at different temperatures were used to fit the diffusion equation to obtain the diffusion coefficient and surface concentration of deuterium in tungsten at different temperatures.The results show that as the temperature of the tungsten sample increases,the deuterium diffusion coefficient and surface concentration increase.Then the diffusion coefficient of four tungsten samples is fitted to the Arrhenius formula to obtain the diffusion coefficient-temperature relationship of deuterium in tungsten samples,which lays a foundation for predicting the diffusion ability of deuterium in tungsten materials under higher temperature conditions.In the same way,diffusion coefficients and surface concentrations at different implantation times are obtained.The results show that the diffusion coefficient and surface concentration of deuterium in tungsten remain basically unchanged with the increase of injection time,indicating that the diffusion of deuterium in tungsten is independent of the surface solubility and injection time.The research work in this paper not only provides a theoretical basis for the cleaning of the first wall,but also provides important data input and theoretical support for the selection and application of the first wall material.It has practical significance for the application of the first wall tungsten material in the Tokamak device and the post-wall cleaning process.