Modeling And Calibration Of The Magnetic Energy Spectrometer Used In The Experiment On The Interaction Between Low-energy Ion Beam And Plasma

The energy deposition of ion beam in plasma is of great significance to understand the interaction mechanism between ion beam and plasma,the evolution and instability of plasma.The energy deposition is related to the type,energy of ion beam and plasma state parameters.In order to carry out the experimental study of the energy deposition,it is necessary to accurately measure the charge state and the energy of the ions simultaneously.In this thesis,a special ion magnetic spectrometer is developed and modeled,which is mainly composed of a high-stability bending magnet,a large-area position-sensitive detector and a space-matched scattering chamber.It can be used to measure the ion energy and charge state distribution after the interaction between ion beam and plasma in medium and low energy region.The angle of the bending magnet is 45°,the bending radius is 1m,the maximal magnetic stiffness is 1.2 Tm,and the magnetic field uniformity inside the magnet is better than 1/10000.The large-area position-sensitive detector is composed of microchannel plate（MCP）detector,fluorescent screen and charge coupled device（CCD）camera.The sensitive surface length of MCP detector is extended to 400 mm,and the resolution of position spectrum from CCD camera is 100mm/pixel.The improvements enable the ion magnetic energy spectrometer to simultaneously measure the multi-charged states and the energies of the ions.Based on the 30～260 keV/q of He^q+（q=1,2）,O^q+（q=1～5）and Ne^q+（q=1～5） ions provided by the 320 kV physics research platform in Institute of Modern Physics,Chinese Academy of Sciences（IMP-CAS）,we have completed the calibration of the magnetic energy spectrometer.The relationship between the excitation current of the bending magnet and the average magnetic induction intensity is obtained,which is slight deviant to the value in the center of the magnet since the edge field effect.The quantitative relationship between the position spectrum from the ion detector and the energy spectrum is provided.The results show that the accuracy and energy resolution of the magnetic spectrometer are 0.1%and 0.8%under the experimental conditions,which are better than those of the time-of-flight energy spectrometer.The ion magnetic energy spectrometer provides a hardware guarantee for the future experimental studies on the interaction between ion and plasma in the medium and low energy region.