Status and First Results of Two High Beta Prototype Elliptical Cavities for ESS

Two prototypes of elliptical superconducting cavities have been designed and manufactured for ESS. These 704.42 MHz. 5-cell cavities have a beta value of 0.86 and the nominal accelerating gradient on the ESS accelerator is 19.9 MV/m at 2 K. We present the manufacturing status of the cavities by two different vendors. We emphasis the activities performed on the first bare cavities recently received at CEA such as the RF measurement and tuning operations, the cleaning and chemical treatments and the clean room assembly including high pressure rinsing. Finally, first test results at 2 K in vertical cryostat are reported.