Design And Experiment Study Of IH-DTL Linac

Heavy Ion Research Facility at Lanzhou(HIRFL)consists of a Sector Focusing Cyclotron(SFC),a Separator Sector Cyclotron(SSC),a main Cooling Storage Ring(CSRm)and an experimental Cooling Storage Ring(CSRe).The SFC which is the only injector at present can only supply injection beam to either SSC or CSRm at one time.Currently,a CW heavy ion linac injector named SSC-LINAC is proposed to improve the operating efficiency in Institute of Modern Physics(IMP).It can provide 0.58 Me V/u or 1.025 Me V/u heavy ions beam with mass-to-charge ratio from 3 to 7.SSC-LINAC mainly consists of an Electron Cyclotron Resonance(ECR)ion source,a Radio Frequency Quadrupole(RFQ)and four Interdigital H-mode Drift Tube Linacs(IH-DTL).Beam dynamic optimization design,RF structure design,low level RF measurement,power coupler design,high power RF conditioning and beam commissioning of IH-DTL1 in SSC-LINAC are discussed in this thesis.The DTL and the associated beam line are simulated with Particle-In-Cell(PIC)method.The problems in RF measurement and high power RF conditioning of the IH-DTL1 are analyzed and solved.Meanwhile,these problems are also optimized in the design of IH-DTL2.The beam commissioning result shows the availability of the beam dynamic design about the SSC-LINAC.According to the dynamic simulation results of the IH-DTL1 in SSC-LINAC,it is found that the energy of beam extracted from IH-DTL1 can be tuned continuously in a certain range with good beam quality.And it is validated by the beam test result.Moreover,by the beam dynamic analyzing about the SSC-LINAC,IH-DTL3 and IH-DTL4 can be replaced by one IH-DTL cavity,which makes the whole SSC-LINAC more compact.Based on the experience of the design and experiment of SSC-LINAC,an update plan is proposed by IMP,which is that using a compact linac injector named HIMM-LINAC to replace the cyclotron injector of Heavy Ion Medical Machine(HIMM).This linac injector can greatly increase the current and quality of the injected beam.The beam dynamic design of the DTL section in the HIMM-LINAC is carried out in this thesis.The KONUS dynamic scheme is adopted to make the DTL very compact.So the DTL section includes only one IH-DTL cavity.By the optimizing of the dynamic parameter,the beam emittances growth is less than10%,and the error tolerance is enough for the beam dynamics.The RF structure of IH-DTL cavity in HIMM-LINAC is designed and optimized for the electric field distribution,frequency tuning capability and the power coupler.Finally,the end to end simulation of the DTL section with MEBT and HEBT in HIMM-LINAC is performed to check the global reliability.Through the research of the SSC-LINAC and HIMM-LINAC,IMP gains rich experience about the design and operation of the normal conductivity linac.