Design And Beam Commissioning Of Beam Lines For CADS Injector II Prototype Linac

The high-level radioactive waste generated by nuclear fission energy brings long-term nuclear contaimination threat to the biosphere and humanity. Accelerator Driven Subcritical system(ADS) is the most effective tool to dispose the nuclear waste. For the key technology pre-research of ADS, the Chinese Academy of Sciences lauched the “Strategic Technology Pilot Project of Advanced future fission energy”. The Chinese ADS Injector II prototype linac is designed and constructed at Institute of Modern Physics. The research goal of Injector II prototype linac is to study the low energy high current continuous wave Superconducting linac and provide a possible solution for the low energy section. The major work of the dissertation is the design, construction and beam commissioning of Medium Energy Beam Transport line I(MEBT1) for Injector II prototype linac.As world’s first 10 m A continous wave(CW) MEBT1 to match beam from RFQ to Superconducting(SC) section with very low losses in SC section, MEBT1 adopts compact layout to control the beam quality by lowering the emittance growth driven by non-linear RF field and space charge effect. In MEBT1, Two quarter wave resonator(QWR) cavities match beam longitudinally, and two triplets and one single quadrupoles match beam transverslly from unsymmetric RFQ exit beam to symmetric SC section entrance beam. The MEBT1 possesses a large range of matching ability to meet the requirements of subsequent SC section. Correctors and BPMs occupying same location of quadrupoles, help to realize the compact layout of MEBT1. A diagnostics box is placed at the middle of MEBT1 to monitor beam online. With beam based BPM offset calibration, the MEBT1 orbit is corrected. With directive emittance measurement and lattice verification, the transverse transport is understood. With buncher phase scan, cavity voltage calibration and beam bunch length verification, the longitudinal transport is roughly understood.Stable operation of one cavity Test Cryomodule 1(TCM1) with 10 m A CW beam, six cavities Cryomodule 1(CM1) with 5.3 Me V, 10 m A, 100 us, 100% transmission pulse beam and CM1 with 5.1 Me V, 2.7 m A CW beam for 5 minutes, shows that MEBT1 has realized matching from RFQ to SC section, making Injector II prototype linac the highest average current and highest power low energy Superconducting linac.This dissertation also includes the design study of MEBT2 and HEBT. At MEBT2, the longitudinal collimation scheme is firstly designed. Simulation shows that the longitudinal beam halo is collimated.