Beam Dynamics Design And Research Of The Linac Injectors In HIRFL

Heavy Ion Research Facility at Lanzhou (HIRFL) consists of four accelerators, a SectorFocusing Cyclotron (SFC), a Separate Sector Cyclotron (SSC), a main cooling storage Ring(CSRm), and a cooling storage ring for experimental (CSRe). SFC is only injector at HIRFL.Only one of SSC and CSR can work at a moment, as suppresses the operation efficiency ofHIRFL. In order to improve the performance of HIRFL, two heavy ions linac injectors areproposed at the Institute of Modern Physics (IMP). One is the injector of SSC calledSSC-LINAC, which supplies0.58MeV/u or1.025MeV/u heavy ions beam for SSC，corresponding to6MeV/u or10.7MeV/u of SSC extraction energy. The beam can be directlysupplied to the experimental terminal, or injected into HIRFL-CSRm to be further accelerated.The other heavy ions linac injector for HIRFL-CSRm, named CSR-LINAC, supplies7.272MeV/u heavy ions. The beam dynamics design, simulation and optimization of SSC-LINACare shown in this paper, as well as beam dynamics design and research of the two mainaccelerating structures in CSR-LINAC.Considering of the special performance of SSC, the RF frequency of SSC-LINAC is set at4times of the RF resonance frequency in SSC with the prebuncher upstream the RFQ, toimprove the injection efficiency of SSC. Based on the previous beam dynamics scheme, anew beam dynamics design including double-gap sawtooth prebuncher is proposed.Compared with the single-gap scheme, it is improved greatly in bunching efficiency andoperation stability. In this thesis, the systematic beam dynamics researches are shown with theanalysis of misalignment instability, based on the RF commissioning of RFQ. According tothe new principle, the medium energy beam transport (MEBT) line is optimized. Based on theoptimization beam dynamics scheme, the end-to-end beam dynamics simulations are carriedout, as well as combined error study adopting magnet measurement database. A new beamdiagnostic scheme, steering magnetic scheme and alignment requirement report are proposedin this thesis.The conceptual design scheme of CSR-LINAC is presented in this paper. AfterCSR-LINAC is finished, the advanced performances of HIRFL are exhibited in this thesis, including the operation efficiency of HIRFL and the beam optimization performance ofHIRFL-CSR. A new strategy for the determination of the main characteristic parameters inCSR-LINAC is described in detail, as the theoretical guide for the conceptual design ofCSR-LINAC. Finally, the beam dynamics design of RFQ and IH-DTL are presented in thispaper, as well as error induced instability and single error sensitivity analysis.