Preliminary Results from Multi-cell seamless niobium cavities fabricated by hydroforming

The technology of forming multi-cell seamless niobium cavities has been developed at DESY within the European CARE (Coordinated Accelerator Research in Europe) program. Three-cell units have been manufactured successfully and a 9-cell cavity has recently been completed from three sub-sections and has been successfully tested at DESY. Additionally, we have equipped two 3-cell units one center unit of a 9-cell cavity and one end-unit with niobium beam pipes, have tuned these units and carried out cryogenic radio-frequency (RF) tests after standard BCP surface treatments had been applied to these cavities. In addition, we have taken temperature maps with JLab s two-cell thermometry system to compare with standard electron-beam welded cavities. This contribution will report about the preliminary cryogenic test results and the T-mapping this is an ongoing investigation.