3HC Third Harmonic Normal Conducting Active Cavity Collaboration Between HZB, DESY and ALBA

A collaboration agreement between the HZB, DESY and ALBA institutions was signed on 2021 in order to test the 3rd harmonic normal conducting, HOM damped, active cavity designed and prototyped by ALBA. The test will involve low power characterization of the fundamental mode, bead pull measurements to fully determine the HOM characteristics, a full high power conditioning to validate the power capability of the cavity, and finally, the installation of the cavity in the BESSY II storage ring in order to test the cavity in real conditions with beam. In this paper the low power, bead pull and conditioning results will be presented. The cavity has been installed at BESSY II on May 2022 to be tested after the summer shutdow