Study On The High Intensity ECR Proton Souce With Beam Extraction And Transmission Characteristics

As the front-end accelerator system injection device, the design of high-currentECR ion source plays an important role in the performance of the whole system.Especially the design of its core components is the key to affect their work performanceand extracted beam quality. Being a beam production equipment, ECR ion source has acompact structure that can produce high density plasma with stable performance andgood repeatability. However, for the ECR ion source system compositioncharacteristics, each core components' performance will affect the quality of producedbeam. Although researchers have done lots of works on the souce experiments, theconvincing explanation of the main factors and relative theories about affecting thesource performance are still not given. For this reason, we need to have a correctdescription and understanding about the key components that relate to the beam qualityand the ion source plasma parameters during the design of the ion source. This researchmethod about the performance of the beam based on plasma diagnostics is right whatwe lack in the research field of high-current ECR ion source design and experiment athome and abroad.In this paper the ECR hydrogen plasma produced in the ECR proton source isinvestigated by using the emission spectra diagnostics tools based on the collisionalradiative model. By comparing their results, the design of the key components of ECRproton source, the beam extraction and transmission characteristics are optimized. Theinnovation is reflected as follows:1. The use of emission spectroscopy diagnostics on ECR proton source to measure theECR hydrogen plasma emission spectra, especially the blamer lines of hydrogenatomic emission spectrometry varies with the experimental conditions. Caculatingthe plasma parameters like electron density and electron temperature by using asimple collision radiation model of the hydrogen plasma. Besides, we comprare theECR hydrogen plasma parameters in cw mode to which in pulse mode ofmicrowave generator, we point out the vatiation of hydogen plasma emissionspectra intensity along with time in one duration of microwave signal for the firsttime from an engineering view, providing an effective reference to the pulse beam extraction and the design of microwave generator parameters in the time scale.2. This diagnostic method effectively connects the plasma parameters with beamcurrent intensity in the condition of different microwave power, providing andexplaining an important reference of the optimum pressure range during the beamextraction, as a result, the efficiency of the ion source is improved.3. The emission spectra of ECR hydrogen plasma varation with the extracted andsuppressed voltage along with the influence of beam to plasma parameters duringthe beam extraction are preliminary investigated with the aim of shedding light onthe mechanism for beam extraction, it is instructive for futher improving the beamintensity and the stability of the ion source.We manufact a new compact ECR proton source and LEBT (Low Energy beamtransport) system, the design method of the key components for this system arediscussed systematically using theoretical simulation and experimental comparison onthe core parameters, thus optimizing their key parameters. By using the emissionspectroscopy method, relations are obtained between ECR hydrogen plasma parametersand key components of the proton source as well as different experimental parameters,and thus influences the intensity of beam extraction.