Experimental results on 700 MHz multicell superconducting cavity for proton linac

The first five-cell niobium superconducting cavity (700 MHz, /spl beta/=0.65) has been successfully tested in the horizontal cryostat CryHoLab. Technological choices like equipment with stainless steel helium vessel and flanges appeared to be viable for the future. Preceding this test, several operations have been performed: field flatness adjustment, chemical etching, heat treatment and RF measurements in a vertical cryostat. Good performances for a multicell cavity were obtained. However, field emission and not yet elucidated phenomenon limit the accelerating field around 16 MV/m.