Non-destructive Beam Profile Monitor-IPM And BIF

As an important part of beam diagnostics in accelerator facilities,beam profile measurements and their continuous monitoring are important during routine operation as well as for accelerator experiments to optimize parameter settings,study the space charge effect and transverse beam cooling process,and so on.An accurate measure-ment is important to control the beam width,as well as the transverse matching between different parts of an accelerating facility.Profile measurement instruments can be clas-sified into non-destructive and destructive devices.Comparing with the traditional in-tercepting profile detectors,the non-invasive profile devices can easily deal with very high intensity beam and perform the real-time profile monitoring.As the nondestruc-tive methods,the Ionization Profile Monitor(IPM)and Beam Induced Fluorescence monitor(BIF)are well suited for synchrotrons or high intensity beam transfer lines.But the research about those two monitors just start not long and they are barely ap-plied in domestic accelerators.In order to meet the requirements of the nondestructive profile measurements in the cooling storage rings of HIRFL,as well as high intensity profile measurements in future CIADS and HIAF projects,the research in this thesis about the developing of non-destructive IPM and BIF monitors has great necessity and significance.IPM and BIF monitors are both based on the ionization and excitation procedure between residual gas molecules and beam particles.The IPM measures the ionization production from the interaction of the beam and residual gas.In IPM the resulting elec-trons or ions are accelerated by an external electric field to a detector having a spatial resolution.For the BIF,a profile is obtained by the observation of fluorescence emit-ted during the residual gas molecules' deexcitation.IPM and BIF monitors are based on the same physical interactions between beam particles and residual gas,while the two also have some difference on measurable signal species and their processing pro-cedures.Both IPM and BIF monitors play an important role in the profile measurement application for high power and intense current beams.The main contents presented in this work are the introduction of the research back-ground,development history and basic principle of IPM and BIF monitors,as well as the analysis of the main affecting factors for two monitors such as the nonuniformity of electrostatic field,space charge effect and complex electron source.Additionally the design,beam experiments and further optimization of IPM and BIF monitors are also presented with details and emphasis in the dissertation.Based on the requirement of profile measurement during high power conditions for ADS Linac 10 mA CW beam,the BIF is proposed and investigated.In the beam experiments at HIRFL-TR2 terminal,the research about BIF measurement performance under different working gas pressure has been done successfully,as well as the research of fluorescence spectra emitted by gas molecule deexcitation.By comparison with a traditional wire scanner,the accura-cy and reliability of BIF have been verified.And with a spatial resolution of 115 ?m,this non-intercepting detector can meet the requirement of profile measurement in ADS Linac and future CIADS projects.The IPM is mainly proposed and developed for the application of real-time profile monitoring in HIRFL-CSR.From the beam experiments in SSC Linac,the relationship between the electric field uniformity and the IPM measurement performance has been researched.By the measurement comparison experiments,the profile result of IPM also shows a good agreement with the wire scanner.Now the IPM has been installed in HIRFL-CSRm for regular profile monitoring with the bias voltage way upgraded.With the characteristic of high spatial resolution about 55 ?m,this IPM can easily meet the need of profile measurement for the cooled beam with very small emittance in CSRm.In the end of dissertation,a new compact design with the function of one IPM detecting the profile of both transversal directions is presented.This new structure can save a lot of space and funds for profile measurement and especially shows a great deal of practicability for the profile diagnostics at the space shortage accelerators like ADS and future CIADS.