Design And Experimental Study Of A Compact Electromagnetic Separator Of High Intensity Ion Beam

High purity isotopes of heavy metal elements are widely used in various applications,including nuclear research,medical radioisotopes production.The electromagnetic isotope separation is an effective and most commonly used process to separate and enrich the high purity metal isotopes due to its advantages of high enrichment factor and versatility.On account of the requirements of high purity metal isotopes,a compact electromagnetic isotope separator,which with gradient magnetic field,large aperture(40 cm×24 cm)and high mass resolution(～2000)was developed based on the typical separator design.For the purpose of increasing the mass resolution with compact separator size,the gradient magnetic field design was used to enhance the mass dispersion and without increasing the radius of separator as well.The magnetic field of separator was analyzed and optimized by synthesizing the results of theoretical calculation,three-dimensional magnetic field and particle tracing simulation,and the second order aberration that induced by extraction beam transverse divergence angle was eliminated and the mass resolution also was increased effectively,which makes it possible to achieve the theoretical design goal.The space charge effect of the high intensity isotopes beam separation was studied via three-dimensional beam optics simulation,the three-dimensional simulation of high intensity isotopes beam from beam extraction to separation was completed,the influence of space charge effect on isotopes separation was systematically estimated.The space charge effect of the beam could influence the mass resolution effectively,therefore the beam transmission and separation under different space charge compensation factors were focused and assessed in this dissertation,and the optimum operation gas pressure also was estimated,which could use as the theoretical basis for the gas pressure control during the separator operation.Taking into account the beam transmission efficiency and separation,an extraction system for high current beam extraction also was designed for purpose of increasing the isotope production yields.The design,assembly and test of high precision 180°separator with gradient magnetic field was completed;the engineering problem of physical design,positioning and installation of 180°square vacuum pipe with large aperture of 40 cm×24 cm was solved;the designed compact electromagnetic separator was set up,the performance studies of separator and high intensity isotopes beam separation experiments were completed;the reliable measurement of beam position and density distribution at focal plane was accomplished via detection and analysis of beam spot image formation at focal plane.Based on above conditions,the separation of heavy element isotopes with magnitude of 10 m A beam current was tested,the experiment results are consistent with the theoretical expectation,the simulation results of mass resolution and space charge effect were verified,the used analysis methods also were tested.The optical properties of the separator were studied by using the natural abundance Xe isotopes,the experimental results showed that the optical properties of separator are accordance with the simulation results.The mass resolution under the different space charge compensation factors and beam currents were studied,the experiment results are consistent with the theoretical expectation.On this basis the space charge compensation factor inside the separator was estimated,the optimum operation gas pressure was confirmed.