Four-dimesional Emittance Study Of The High Charged State High Inensity Heavy Ion Beams Extracted From ECR Ion Source

According to the research requirement of transverse coupling on the ion beams extracted from ECR ion source and the Afterglow beam transverse property,a Pepper Pot meter meeting ECR ion source extraction energy was firstly developed,the goal of the Pepper Pot meter was to measurement the ion beam four-dimensional?4D?emittance.The research in this dissertation mainly includes three aspects:?1?The total design of PEMiL?Pepper Pot Emittance Meter in Lanzhou?and developing a data processing code;?2?Results certification of PEMiL.?3?Transverse phase space coupling and pulsed beam property research.As the 4D emittance measurement meter,the advantage of Pepper Pot meter is its rapid acquirement time,the instant beam emittance of ion beams with shot time structure can be obtained theoretically.According to the charactics of ion beams from ECR ion source and the reaserch requirement of this paper,the main hardware structure of PEMiL used single measurement scheme.During PEMiL developing process,using the bromatum kalium?KBr?crystal powder instead of pure cesium iodide?CsI?scintillator to generate beam spot,the overlapping effect was vanished successfully.In addition,the optical experimental analysis results have proved that the mirror surface irregularities are the distortion reason of transverse phase space distribution,and this distortion has been vanished through optimizing the mirror suface evenness to hurdred micrometer.A self-developed code was uesd to proess and analyze beam spot image.The overall expriments certified that PEMiL designed at IMP shows a stable performance,and it can be used as the beam property diagnostic device theometically.The transverse phase space distribution measurement result of Pepper Pot meter is sensitive with external hardware parameters so that the results show uncertenty.But another type emittance meter Allison Scanner,because of its working mechanism,it may not a best meter to measure ion beam 4D emittance directly,but it exists low system error samller than 10%,so that its 2D emittance measurement results is closed to the real value.In order to obtain the difference,the 2D ellipse measurement paremeters of PEMiL was cetified to that of Allison Scanner.And the final certification data shows that the highest discranpency of transverse 2D phase space ellipse is about 20%,and the smallest is only 4%.It is a conclusion that the Pepper Pot meter developed at IMP can be used as the beam transverse phase space coupling and Afterglow pulse beam property diagnostic device.Based on PEMiL,the transverse 4D emittance and full coupling elements of 75keV,60 e?A O⁵⁺CW ion beam extracted from LECR4 were obtained.The experimental results have show that beam transverse 4D emittance is constant but 2D emittance has exchanged between horizontal and vertical with G02 different polarity and current.The transverse phase coupling charactsitics were comfired experimentally.Based on PEMiL,the transverse emittance of 75 keV,400 e?A O⁵⁺Afterglow pulsed ion beam was obtained throngh multipule accumulation exposure method.As the certification with the Allison Scanner,the final results shows that emittance obtained through multipule exposure method is highly credible,so that multipule accumulation exposure method is the effective shceme to measure the Afterglow peak beam emittance.Based on PEMiL,with G02 different polarity and current,the 4D emittance of DC and Afterglow peak beam was acquired.The measurement results have shown that because ECR ion source plasma equivalent radius is larger than extraction electrode radius,the 4D emittance of DC beam is greater than that of Afterglow peak beam.