Radiation Field Of High Energy Electron Accelerator

Permanent magnets are widely used in the insertion devices of the particle accelerator and synchrotron radiation devices. These permanent magnets are usually in a mixed strong radiation field and easily suffer the radiation damage, and then some serious effects possibly occur. Therefore, the radiation-induced demagnetization is a big issue in the particle accelerators and synchrotron radiation devices. It is necessary to investigate the radiation field in the high energy electron accelerator. It is not only quite meaningful for the radiation-induced demagnetization of permanent magnets but also for the health physics and radiation physics problems.In this thesis the theoretical analysis on the radiation field in the high energy electron accelerator has been done first. High energy electron initiates the electromagnetic shower and then generated a lot of bremsstrahlung and secondary electrons with wide spectrum. Photoneutrons and protons will be produced in the electron linear accelerators, when the bremsstrahlung energy exceeds the threshold energy of photonuclear reactions of the materials.The radiation field is simulated with Monte Carlo code FLUKA. The spatial distribution of the particle fluence and the energy deposition is calculated by simulating the transport of the high energy electrons.The absorbed dose and 1MeV equivalent neutron fluence by 2.5 GeV electrons emitting a Cu target is measured with new type radiation damage monitor (RDM). RDM is made of 2 p-channel enhanced field effect transistors (RADFET) and 1 PIN diode. At first the temperature character and angle response is investigated. Then the sensitivity of the RADFET is calibrated by 60Co and 137Cs gamma sources, and the PIN diode is calibrated by 252Cf neutron source,65MeV accelerator neutron source and 14.1MeV accelerator neutron source. Finally the doses and 1MeV equivalent neutron fluences at different angles from the Cu target are measured by putting RDM probes at six different angles. At the same time, the corresponding physics processes are simulated with FLUKA. The good agreement is found in the comparison between the experiment results and calculated results.