HOM damper for Accelerator and fusion Field

Our customer incurred the following problem; when accelerating electrons and protons up to the speed of light, niobium superconducting cavities are used but at the same time, higher harmonic waves occur inside of the cavity due to the acceleration. These higher harmonic waves disturb the desired acceleration due to energy loss. As a consequence absorbing the higher harmonic wave using ferrite was vital. Usually, brazing a ferrite plate to copper is a solution; however in this situation this had several issues. An example was that some parts remained that were not bonded and when used in this condition, the parts which don’t radiate heat well struggled in lowering the capacity of higher harmonic wave absorption. Also there was a risk of generating particles due to a defect caused by an overly heavy heat load on the edge section as it became over heated without the complete bonding.

By lining the ferrite on the inner surface of the Copper cylinder, a uniform ferrite layer was formed, and the temperature rise was suppressed through eliminating the inconsistency of cooling due to the failure of the bonded area.

Because of the lining’s inner surface uniformity the possibility of defects around the edge was decreased and as a consequence the generation of particles was suppressed.