Research On Simulation And Optimization Of HIRFL-SFC

The Sector-Focused Cyclotron(SFC) as the injector of Heavy Ion Research Facilityin Lanzhou (HIRFL) has been upgraded and reconstructed by1987. From then on,SFC provided many different heavy ion beams to SSC and CSRm for scientificresearch and related application. However, as the requirements of experimentsincreased, higher beam intensity and quality should be provided. According to thesimulation results and actual operation situation of SFC, several factors which affectSFC transmission efficiency are expounded and three following aspects are studied.(1) The isochronous magnetic field for different particles is calculated by Gordonpmreotcheosdse. dA tnhde othpee roatpieorna tmioang nmeatigcn feiteilcd foief ld4is+aenstablished by OPTCC program. Wehde aHc2+with Fourier analysis and gotthe betatron tune, the equilibrium orbit and tceleration orbit to analyze theinfluence on transmission efficiency.(2) For proton beam works at lower field level of SFC, there is large differencebetween isochronous magnetic field and operation magnetic field at central region.And the magnetic field could be optimized by increasing the current of the first threetrim coils. Results show that the difference between isochronous and optimizedmagnetic field can be significantly reduced. This is very useful for accelerating protonbeam.(3) It is very useful for using flattop acceleration (FT) system to reduce the energyspread of extraction beam. In this paper, we calculated the beam quality of SFC byusing the beam simulation program AGORA-SCE and compared the results betweenwith and without FT system. The results show that the energy spread reduces sharplywith FT system. And at the entrance of extraction deflector, the beam width of theradius direction and turns separation meet the conditions of single turn extraction.