UPDATE ON LARGE GRAIN CAVITIES WITH 45 MV/M IN A NINE-CELL CAVITY AT DESY

Since 2009 a series of eight nine-cell cavities (AC151 - AC158) of TESLA shape fabricated of large grain (LG) niobium material is under preparation and test at DESY. In a first step all cavities were tested after a BCP treatment. In a second step additional electro polishing is applied to all cavities. In this paper the treatment will be discussed and a first excellent result of AC155 will be reported. MATERIAL AND FABRICATION