|
In this paper, we study the optimal structure and design of bremmsstrahlung converters include the main target, the waterlayer, and the stainless steel base. We select the best target thickness as the main target, the optimal design of waterlayer and the proper thickness of stainless steel. After this, we get the ultimate Bremsst-rahlung converter. Lastly, Compared to the experimental data to verify the calcula-tion program BEAMnrc and MCNP, in order to provide the calculation base for optimal design.Firstly, we select the best target thickness as the main target.We select high Z material W, Au, Ta as the main target. The calculation process and principle of target thickness for irradiation linac is the same as the NDT-LINACS’, that we calculated the dose rate away from the target center lm and the bremsstrahlung process conversion efficiency for NDT-LINACS 6MeV,which uses a Monte Carlo program BEAMnrc, and with specific analysis the physical mechanism of the interactions between the beam and the target on NDT-LINAC 12MeV, we combine with targets related theory and verify the MCNP simulation program, and then make some related experimental testing to confirm the calculation results. Finally, we get the best target thickness as the main target for 5MeV LINAC, which considered the maximum energy conversion efficiency of different materials.Secondly, the optimal design of water layer. By ANASYS CFX, we compare the margin of temperature and the pressure on which both input and output on wall sections and the narrow sections, we provide the best reference to the water layer thickness, the way out of water and the water mass flow required.Lastly, according to the actual pressure, absorption of X ray, the physical stability and the welding process, we select proper thickness of stainless steel.Considering the sealing and welding technology, we get the ultimate Bremss-trahlung converter. Experimental data verification target parameters, which inclu-des pressure testing, on-site water flow, import and export water temperature, the dose rate distribution 20 cm away from the target surface plane, measurement of related dose and converter efficiencies, and confirm the calculation results.
|