Low Impedance Bellows for Particle Accelerator in Jefferson Lab

**Student:** Adarsha Sapkota

**School:** Virginia Commonwealth University

**Mentored By:** Tim Michalski

The main purpose of this research project was to assess the effect of different variables on the loss factor and impedance of the formed bellows design. The analysis involved stress, deformation, loss factor and impedance analysis of the bellows with length of 300 mm and inner diameter of 110 mm. It was found through analysis that the material thickness is directly proportional to the number of convolutions and loss factor changed significantly with the increase or decrease in inner diameter. The results at first consisted of stress analysis, impedance and loss factor calculations for the bellows with radius, height and spacing between convolutions pair of 2 mm, 8.15 mm and 86.34 mm respectively. After that, the radius was increased to 3 mm, height was decreased to 6.15 mm, and spacing increased to 100 mm to evaluate the impact upon the bellows. The stress increased for the latter analysis in comparison to the first one. Therefore, the dimensions have to be set in between 2 mm and 3 mm radius for each convolution for the process of optimization. These results will provide the researchers and scientists a proper way to reduce beam instabilities and particulates generation.

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