The Intercepting And Stopping Mechanism And Components Optimization Design Of The High Power Beam

The high power beam intercepting and stopping components are key equipments in the superconducting linear accelerator of the China Initiative Accelerator Driven System.They are mainly used for the control of the beam intensity,the scraping of the beam halo,the diagnosis of the beam and the collection of waste beam.They mainly include beam limiting adjustable aperture,beam scraper,Faraday cup,beam profile and beam halo monitors,beam dump and other components,which are respectively located in the low-energy,medium-energy and high-energy transmission lines of the superconducting linear accelerator.Three kinds of beam intercepting and stopping components are taked as the research objects in this dissertation,the mechanism of interaction between 25 MeV proton beam and several materials was studied,according to the Bragg peak energy deposition curve of proton beam in the material,a practical heat source model was established.In order to solve the defects of existing beam debugging and beam limiting methods,a continuous adjustable beam aperture was developed.This design can be used as a reference for accelerator devices with the same requirements.Aiming at the practical problems such as small flange aperture and large probe travel in the prototype installation site,a prototype of multi-wire beam profile and beam halo monitors was developed,an effective solution was put forward and successfully implemented.This work has certain reference significance for other similar accelerators.Aiming at the problem of existing beam dump,the structure design and optimization analysis of thermal-fluid-solid coupling parameters of the high power beam dump were carried out,which provides guidance for the development of the prototype of the high power beam dump.The main research contents and conclusions are as follows:(1)The transport process of 25 MeV proton beam in several materials was simulated by monte carlo method,the mechanism of interaction between proton beam and material was studied,and the energy deposition and damage distribution of proton beam in different materials were calculated.The results show that the collision of protons with the nucleus of the target material makes the lattice atoms of the target material shift,vacancy and interstitial atom,among which vacancy plays a major role in the influence of material properties.The lower the density of the target,the less vacancy caused by protons in the target and the less damage to the target.This provides a basis for the establishment of the heat source distribution model of proton beam in the material.Thus,the material selection of the beam intercepting and stopping components is guaranteed to meet the use requirements.(2)According to the energy deposition in the proton beam in different materials,the mathematical models of surface heat source and body heat source of proton beam incident materials were established,which provides a theoretical basis for the analysis of thermal-fluid-solid coupling of the beam intercepting and stopping components.(3)In order to meet the requirement of continuous wave mode operation of C-ADS superconducting linear accelerator,the structure design of the beam limiting adjustable aperture for low energy beam transport line was completed,thermal analysis and structure analysis were carried out,and the prototype was developed and tested online,the beam current of superconducting linear accelerator is continuously adjusted from 0 mA to 10 mA,which provides a convenient beam tuning method for proton linear accelerator.(4)For the high power beam physical characteristics research of the target and the limit of the installation environment,a multi-wirebeam profile monitor of multipoint position suitable for small pipe was proposed,the multi-wire beam profile probe adopts multi-point positioning method to realize the arrangement of 8 transverse and longitudinal signal wires on the front and back of a ceramic substrate with a length of 120 mm,a width of 34 mm and a thickness of 5 mm,with a spacing of 2 mm.Due to the compact structure,the problem of difficult installation and operation in the small pipeline,large probe travel and small wire spacing was solved.According to the requirement of beam measurement,the structure design and processing of the prototype were completed.Through statics analysis and off-line test of the prototype,the performance of the prototype is guaranteed to meet the demands.(5)Based on the results of proton beam interactions with materials and radiation calculation,carbon and carbon composites with good thermal conductivity and low activation dose was selected as beam oriented materials for high power beam dump.The SolidWorks software was used to build a 3d model of the beam dump with different structures and cooling system.The thermal-fluid-solid coupling analysis of the beam dump was carried out with the ANSYS Workbench,and the influences of different structures parameters and operating parameters on temperature field,thermal stress and thermal deformation were compared to complete the design and optimization of the high power beam dump.