Simulation Study Of Photonuclear Medical Isotope Generation Based On Laser Accelerated Electron Source

In recent years,"Nature" magazine has repeatedly reported the crisis of shortage of medical radioisotopes,and it is urgent to study new ways to produce isotopes.With the continuous innovation and development of ultra-strong ultra-short pulse laser technology,photonuclear isotope generation is regarded as a very effective and realistic way to provide radioisotopes for nuclear medicine,molecular imaging,molecular biology and other foundations Scientific and applied research.This paper is a simulation study of photonuclear medical isotope generation by laser accelerated electron source,The thesis consists of the following five chapter:The first chapter,Introduction.briefly introduces the application of radioisotopes in medicine and the conventional methods of generation;with the development of ultra-strong ultra-short laser technology,it provides favorable technical conditions for the production of medical isotopes produced by ultra-strong laser-induced photonuclear reactions;The research achievements and progress of the y radiation mechanism induced by strong laser at home and abroad have been introduced.In the second chapter,the selection and generation of the photonuclear medical isotopes of interest.we introduce in detail the selection of several medical isotopes of interest,and discuss the generation mechanism of photonuclear medical isotopes and their photonuclear generation cross sections.The photonuclear medical isotope generation mechanism used in the simulation is mainly photoneutron reaction and photoproton reaction.Using the TALYS program,the generation cross sections of several medical isotopes(69Ge,68Ga,64,62Cu,47,44Sc)are calculated.The third chapter:the laser accelerated high charge electron source and bremsstrahlung generation.This is mainly summarized as the high charge electron source-bremsstrahlung gamma source with high charge and high energy accelerated by the ultra-strong ultra-short laser.First,a 3D-PIC(3D-Particle in cell)particle simulation program is used to construct a physical model of an ultra-strong ultra-short laser accelerated high charge electron source.The 340 TW ultra-strong ultra-short laser with NCD(Near critical density)plasma interaction process in the range of 0.1-1.5 nc were simulated,and discussed the effect of plasma density on the accelerated electron beam.Secondly,based on the Monte Carlo(MC)program-Geant4 software package,constructed the laser-accelerated electron source-granular radiation gamma source physical model.The high charge electron source obtained by laser acceleration is used as the incident particle source,study the effect of plasma density and target atomic number on the bremsstrahlung gamma spectrum.The fourth chapter;the production of photonuclear medical isotopes driven by laser accelerated electron source.We used the Geant4 software package to build a physical model of photonuclear medical isotope generation based on a laser-accelerated electron source,and conducted photonuclear generation research on the medical isotopes of interest(69Ge,68Ga,64,62Cu and 47,44Sc).Simulate and diagnose the effects of plasma density,conversion target(tantalum target)and target target thickness on photonuclear reaction yield;and the dependence of medical isotope activity on irradiation time and laser repetition frequency.The fifth chapter,the experimental scheme of photonuclear medical isotope generation by laser accelerated electron source.It is planned to use the hundred-terawatt-class laser device XingGuang III,carry out a photon medical isotope generation experiment driven by a picosecond/femtosecond ultra-strong laser.The experiment is divided into two parts:online irradiation and offline measurement,and the efficiency calibration simulation of the high-purity germanium detector used in offline measurement.The strong laser-driven photonuclear reaction method adopted in this paper has the ability to produce interesting medical isotopes.It provides positive theoretical guidance for the experimental research of photonuclear reactions based on desktop laser accelerators,and provides potential physical solutions for medical isotope production.