Research On Radiation Field Of Machine Hall And Radiation Room On Low-energy Electron Irradiation Accelerator

Nowadays, irradiation electron accelerator is widely applied in material modification, food preservation, medical supplies sterilization, etc. The X-ray and electron made by electron accelerator possess many merits such as low-energy consumption, manageable, scathe less, the beam is stable and concentrated, and this accelerator has increasingly become the main equipment in irradiation processing industry. Although the shielding design become more perfect, some details design still need to optimize, in order to make the accelerator shielding design meet the requirements of economic and effective, discuss the radiation shielding optimization of internal structures in electronic irradiation accelerator is of great importance.This paper first expounds Monte Carlo simulations in the machine hall on a low-energy Dynamitron in Anhui province, emphatically exploring the influence degree of holes types on the dose distribution in the main hall, and making measurements of distribution dose rate. For some drift tubes with fixed diameter, obtained the reasonable diameter and shape of the hole. The size of hole has tiny effect on the dose rate in vertical direction; while the dose rates in the horizontal direction change apparently because of diameter. Adding stair-step platform in accelerating pipe hole is not only helpful to save the axial height of accelerator, but also effectively reduce the radiation level around drift tube. The variance reduction technique was applied in simulating irradiation room that leading lower errors and achieving the reasonable range of total thickness. Recorded X-ray emission rate then comparing with the subsequent theoretical results.Then illustrated the calculating theories of main and second X-ray and estimated the X-ray emission rate with formulas and experience data based on NCRP reports; discussed the shielding thickness of main and second shielding and calculated the thickness with the actual accelerator, these two calculated parameters according with simulated data that demonstrating the rationality of the model powerfully Finally we measured the cumulative doses in machine hall and irradiation room with thermo-luminescence dosimeter and dose bottle. The measured data and simulated results with MCNP5in machine hall reflected the dose rates trend conformably, the measured results in irradiation room showed the magnitude change of dose rate clearly.We hope that the data conclusions in this paper can provide theoretical reference for similar radiation shielding calculation; the works are able to helpful for the optimization shielding design in details of the low-energy electron irradiation.