Oveis Hasanpour; Fereydoun Abbasi Davani; Farshad Ghasemi; Mahdi Aghayan; Mohammad Nazari; Shahin Sanaye Hajari
Abstract
Two main insulating gases of SF₆ and N₂/CO₂ mixture are employed to increase voltage capability of electrostatic accelerators. SF₆ offers more insulating capability, but environmental and technical disadvantages of SF₆ makes usage of N₂/CO₂ mixture a desirable option. This paper aims to ...
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Two main insulating gases of SF₆ and N₂/CO₂ mixture are employed to increase voltage capability of electrostatic accelerators. SF₆ offers more insulating capability, but environmental and technical disadvantages of SF₆ makes usage of N₂/CO₂ mixture a desirable option. This paper aims to replace SF₆ with N₂/CO₂ in design of a 500 kV/30 mA parallel-fed voltage multiplier. High-voltage section of the accelerator is a capacitive structure which in combination with rectifying elements, generates the accelerating high-voltage. The structure which is called Voltage Multiplier Capacitive Structure (VMCS) is designed and analyzed in this paper. The first structure is designed to employ SF₆ as insulating gas (VMCS500). Then, the structure is modified to be capable of using N₂/CO₂ as insulating gas with lower breakdown voltage (VMCS500-m). The modified structure requires more complex mechanical manufacturing process, but offers the simplicity of using N₂/CO₂ mixture, the option of using the modified structure with superior SF₆ gas, increasing the output voltage and beam energy. CST EM STUDIO was used for capacitance calculation and electric field analysis. LTSPICE was used for equivalent circuit analysis of the high voltage generating section.
Mahdi Aghayan; S. Farhad Masoudi; Farshad Ghgasemi; Hamed Shaker
Abstract
Advantage of non-brazing methods in manufacturing of cavities has been considered in high gradient studies because of the softening of copper by brazing cavities at high temperatures. Recent studies with hard copper cavities have been shown that the harder materials can reach larger accelerating gradients ...
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Advantage of non-brazing methods in manufacturing of cavities has been considered in high gradient studies because of the softening of copper by brazing cavities at high temperatures. Recent studies with hard copper cavities have been shown that the harder materials can reach larger accelerating gradients for the same breakdown rate. Shrinking, as a braze-free method for construction of the cavities, was used recently to fabricate and assemble acceleration cavities of an electron linear accelerator at the Institute for Research in Fundamental Science (IPM-Iran). Based on the results obtained in this project, this paper proposes the design of a 3-cell S-band standing wave structure operating at 2.9985 GHz for high gradient tests, considering shrink-fit construction method. The desired cavity consists of three cells so that the maximum gradient in the middle cell is about twice that of the surrounding cells. Simulation with Ansys-HFSS showed that maximum axial electric field 59 MV.m-1 achievable for 2 MW input power in middle cell.