Commissioning results of the HZB Quadrupole Resonator

• DOI: 10.18429/jacow-srf2015-wea1a04
• Publication Date: 2015-01-01
• Authors: Kleindienst, R.; Burrill, A.; Keckert, S.; Knobloch, J.; Kugeler, O.
• Keywords: Fundamental SRF R&D - Bulk Nb; 0103 physical sciences; 01 natural sciences; Quadrupole resonator, cavity; Accelerator Physics

Recent cavity results with niobium have demonstrated the necessity of a good understanding of both the BCS and residual resistance. For a complete picture, and comparison with theory, it is essential that one can measure the RF properties as a function of applied magnetic field, temperature, frequency and ambient magnetic field. Standard cavity measurements are limited in their ability to change all parameters freely and in a controlled manner. On the other hand, most sample measurement setups operate at fairly high frequency, where the surface resistance is always BCS dominated. The quadrupole resonator, originally developed at CERN, is ideally suited for RF characterization of samples at frequencies of 400 and 1300 MHz, between which many of today’s SRF cavities operate. We report on a modified version of the QPR with improved RF figures of merit for high-field operation. Experimental challenges in the commissioning run and alternate designs towards a simpler sample change are shown alongside measurement results of a large grain niobium sample.<br/>Proceedings of the 17th International Conference on RF Superconductivity, SRF2015, Whistler, BC, Canada<br/>