Development Of A Platform For The Study Of Impurity Spectrum Based On Medium Energy Electron Beam Ion Trap

Fusion energy is safer,cleaner and more efficient than fission energy.After decades of research,magnetic confinement fusion is currently regarded as the most promising method of controlled nuclear fusion.While today’s magnetic confinement fusion devices,especially the Tokamak,can produce plasmas with electron temperatures close to 10 keV,future fusion devices can produce plasmas with electron temperatures of 25 keV or more.Therefore,highly charged ions are important part of magnetic confinement fusion plasmas,and their existence is beneficial to the diagnosis of magnetic confinement fusion plasmas and the research of basic atomic physics.But if they are present in large quantities,their radiative properties will reduce the temperature of the fusion plasma,making it difficult for fusion devices to operate.The transport behavior of highly charged ions in plasma has been an important research topic in tokamak nuclear fusion experiments and physics research.Electron beam ion trap(EBIT)is an effective device to study the physical processes of highly charged ions.The construction and operation cost of large EBIT is expensive,and the experiment period is short.Because many experiments do not need such high energy,in order to save the cost,according to different occasions and to meet the needs of relevant scientific research,the low and medium energy compact EBIT has become the development trend.Most compact EBIT uses high temperature superconducting magnets or permanent magnets to replace the original low temperature superconducting coils.It is small in size,convenient to handle,easy to operate,and its advantage greatly reduces the development and operation costs.According to the diagnostic requirements of magnetic confinement fusion device,we propose to develop a platform for impurity spectroscopy based on compact electron beam ion trap in medium energy.The platform is designed to observe the spectral lines of tungsten,iron,argon,xenon and other impurities in plasma similar to the ITER core.The key indicators of EBIT,the core component of the platform,are that the electron beam can reach 30keV,the electron beam current can reach 20mA,and the central magnetic field intensity can reach 1T.We propose to develop EBIT magnets which innovatively use cryogenic superconducting magnets cooled by refrigerator.This scheme allows the EBIT to operate without using liquid helium or liquid nitrogen to cool the magnet.In this paper,the design and development of the medium energy EBIT of the platform are elaborated,and the relevant theoretical basis and testing process are also described.The main work is as follows:1)This paper introduces the background of the development of the medium energy EBIT,and the overall scheme design of the impurity spectrum research platform based on the medium energy EBIT,including the electrode system design,magnet design,high voltage platform design,vacuum system design,gas injection system design,spectrum platform design.2)The development of EBIT low temperature superconducting magnet is introduced in detail,including structure design,electromagnetic design,magnet quenches protection design,design of cryogenic cooling,the insulation of the skeleton,winding coil,the coil assembly of vacuum pressure impregnation,magnet system test.The test results have achieved the expected effect and can meet the magnetic field requirements of EBIT.3)The development of electrode system includes the development of electron gun assembly,drift tube assembly and electron collector assembly.The assembly of the EBIT device includes the assembly and alignment of the electrode system,the connection of the vacuum system and the connection of the power supply system.COMSOL software was used to simulate the electron beam trajectory of EBIT model,which verified the feasibility of the EBIT system parameters.The testing of the EBIT system includes vacuum testing,magnet testing,cathode heating measurement,high voltage testing,beam extraction testing,and spectral testing.The test results indicate that the developed medium-energy EBIT can meet the designed specifications,and the system operates stably as a whole.