Ultimate-gradient srf test cavity and low loss tangent measurements in ultra pure sapphire Conference Paper uri icon

abstract

  • A test cavity has been designed to test wafer samples of superconducting materials at 1.3 GHz. Operating in TE01 mode, this mushroom shaped cavity creates a unique distribution of surface fields. The surface magnetic field on the sample wafer is 3.75 times greater than elsewhere on the Niobium (Nb) cavity surface. This made possible by loading the cavity with an ultra-pure sapphire just above the sample wafer. The maximum field seen by the Nb wall is only 25% of the value deposited on the sample surface. Therefore, it should be possible to push the sample wafer well beyond the BCS limit for Nb while still obtaining a respectable Q. The sapphire's loss tangent and dielectric constant must be measured to finalize the design for the Wafer Test Cavity. A sapphire loaded CEBAF cavity has been constructed and tested; these results on the dielectric constant and loss tangent will be presented.

published proceedings

  • Proceedings - 25th Linear Accelerator Conference, LINAC 2010

author list (cited authors)

  • Pogue, N., Mcintyre, P., & Reece, C.

complete list of authors

  • Pogue, N||Mcintyre, P||Reece, C

publication date

  • December 2011