Research On The Optimization Design Of Medical Linear Accelerator Room Maze

With the development of radiotherapy technology,the rapid advance of radiotherapy equipment,engine room protection design has become the focus.And maze in order to reduce the radiation dose of the entrance to the door,connecting the door and the engine room and after a rigorous design of the channel.In addition,the interior and exterior walls of the lab room are also an important aspect of shielding large areas of scattering and leakage of rays and protecting the public area.Therefore,the design of the maze can make the scattering and leakage of radiation through the attenuation will reach the door,so that the use of the shielding door will be very light to open and close,if not designed,to shield out a lot of scattered lines and leaks need the door being very cumbersome and inconvenient.It is also important that the maze pathways can provide a route for the ventilation ducts and cable passages without affecting the shielding effect of the shielded room.For the specific design of the maze,this paper uses the Monte Carlo method,empirical formula calculation and field measurement method,in order to achieve the best way to design a maze,including the following research :(1)the establishment of a more detailed model of the accelerator head;(2)Using the step-by-step simulation method,the energy spectrum and angular flux distribution after 10 MV were obtained,and the percentage of the depth and the off-axis ratio of the water model were calculated as the source.Measured the results were compared,the results are in line with the good description of the head model and the physical process is accurate;(3)Based on the actual parameters of a medical electronic linear accelerator and engine room in Jiangxi Province,the head model and the engine room model were established.The comparison between the empirical formula of MCNP and maze design and the dose rate at the outlet of the maze was carried out,which indicated that MCNP could be one of the effective Shielding calculation tools,and the use of MCNP on the machine room maze type,maze the inner width and height,maze length,height and other parameters set,the engine room lost the key 5 points to simulate.MCNP simulation and field measurements are the closest,the choice of Z-type labyrinth is more conducive to the design of the protection of the door,lost the width and height of the mouth and the smaller the loss of the smaller,lost the greater the length of the labyrinth of the smaller dose rate.(4)Through the field measurement,the distribution and attenuation of X-ray in the infestation are obtained.(5)The thickness of the inner and outer walls of the labyrinth can be improved by calculating the method of re-generation test.The method of adding the amount of steel fiber titanium fiber can increase the shielding effect and mechanical property.Through the above research,the method of optimization of lost design is obtained.It is hoped that this paper will provide reference for the labyrinth of the engine room and provide help for the related accelerator research and the design of the door.