1.3 GHz Nb-coated cavity irradiated by laser in argon atmosphere and RF tested

The spherical RF cavity with Nb thin film on Cu substrate from UKRI were irradiated using the Nd:YAG laser in the chamber with an Ar gas. Irradiation of the 3D spherical part of the RF cavity by the laser shows that the deposition of Nb thin film on the Cu substrate is nonhomogeneous. Nb coating on the 2D tubular part of the RF cavity is thick, but on the 3D spheric part, it is too thin, less than 1 µk. Therefore, the 3D spheric part has not changed.  Irradiation of the 3D spherical part of the RF cavity by the Nd:YAG laser shows that the deposition of Nb thin film on the Cu substrate is nonhomogeneous. Therefore, it is necessary to prepare the RF cavity with homogeneous Nb deposition on Cu at low temperature and Nb thickness from 3µk to 10 µk.