Radiation Physics and Engineering
A peer-reviewed journal published by K. N. Toosi University of Technology

Replacement of SF₆ with N₂/CO₂ in design of a parallel-fed voltage multiplier for electrostatic accelerator

Document Type : Research Article

Authors

Oveis Hasanpour 1
Fereydoun Abbasi Davani 1
Farshad Ghasemi 2
Mahdi Aghayan 3
Mohammad Nazari 1
Shahin Sanaye Hajari 2

1 Department of Radiation Applications, Shahid Beheshti University, Tehran, Iran

2 Physics and Particle Accelerators Research School, Nuclear Science and Technology Research Institute, Tehran, Iran

3 Department of Physics, K.N. Toosi University of Technology, Teharn, Iran

https://doi.org/10.22034/rpe.2022.329539.1056
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 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.

Highlights

  • Design of a 500 kV/15 kW electrostatic high-voltage generator is presented.
  • Modifications in high-voltage structure make using lower insulating N₂/CO₂ instead of SF₆ possible.
  • The modified structure is capable of generating 500 kV with N₂/CO₂ and 1.1 MV with SF₆.

Keywords

Accelerator
Electrostatic
High-voltage
Cascade generator
Insulating gas
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Radiation Physics and Engineering
Volume 3, Issue 2
Spring 2022
Pages 17-25

  • Receive Date 13 February 2022
  • Revise Date 05 May 2022
  • Accept Date 08 May 2022

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