Research On The Flux Concentrator And Its Solid-State Pulse Power System For Intense Positron Source

The high current positron source system is one of the key equipment in the high energy collider.According to the requirements of high brightness and high energy proposed by the Circular Electron Positron Collider,the physical design of the injector linac proposes higher requirements of positron source,and the charge of its positron beam reaches 3.2nC,which is two orders of magnitude higher than that of the BEPCII positron source.This index will greatly improve the difficulty of the design and manufacture of positron source system.Based on the phase space device behind the positron target,this paper studies the flux concentrator and its driving solid-state pulse power system,which provides the peak value gradient magnetic field,and successfully develops the prototype of the flux concentrator and its driving pulse power system.According to the requirements of peak magnetic field,the flux concentrator model is modeled,and the magnetic field in its axial position is simulated and verified by opera-2d and CST 3D em.when the peak current is increased to more than 15kA,the magnetic field strength can meet the 6T high peak magnetic field proposed by physics.To further verify the feasibility of its high peak magnetic field,a high voltage and high current pulse power supply system based on solid-state discharge switch module is designed and developed.Based on the energy storage discharge topology,the solid-state switch module is selected to replace the heavy hydrogen thyratron as the discharge switch.Based on a series of pulse adaptability and reliability tests,the thyristor switch module is finally selected.Through circuit analysis and simulation verification,the reasonable design of main circuit parameters is obtained to realize the high current pulse output waveform with peak value of 15kA and half width of 5 ?s.In the key equipment and processing technology,as far as possible to choose the approximate coaxial structure design scheme,to minimize the distribution parameters in the circuit.Based on the problem of long-distance transmission of pulse power in practical application,the distributed parameters in the main circuit will cause high-frequency oscillation of pulse current.It is concluded that the distributed capacitance is the cause of the high frequency oscillation in the main pulse.Therefore,the optimization of distributed parameters is proposed to counteract the influence of distributed capacitance parameters.According to the theoretical analysis and simulation,the reasonable parameters are obtained.In the final system joint debugging experiment,it has also been verified.The rationality of the proposed damping circuit design is verified.In the control system,the proposed optimization scheme has also been verified.In the aspect of control system,epics architecture,which is widely used in accelerator field,is selected to design and develop an interlock and protection system with programmable logic device and touch screen as the core,which provides convenient and flexible operation mode and fast and reliable protection logic.According to the requirements of high voltage aging test,the automatic aging control program is developed.Through flexible parameter configuration,the automatic aging control of different power levels can be realized.The automatic aging control has been promoted and applied in 50MW and 80MW high-power test platform,and it also lays a good technical foundation for high-efficiency aging of large-scale acceleration structure in high-energy light source.Finally,the developed solid-state pulse power supply and flux concentrator prototype are jointly debugged,and the final test is in line with the expectation of the project development.At present,the subject has passed the appraisal and acceptance of the expert group,and passed the final acceptance of the Ministry of science and technology.After expert appraisal,the conclusion is that the peak magnetic induction intensity of the pulse center of the successfully developed flux concentrator is 6.2T driven by 15kA pulse current,the stable output of the solid-state pulse power supply is 15.05kA,the maximum charging voltage is 15.1kV,and the half-width of the pulse is 5 ?s.The above indexes all reach the acceptance indexes of the international similar devices.