Author/Authors :
Palmieri، نويسنده , , V and Porcellato، نويسنده , , A.M and Ruzinov، نويسنده , , V.L and Stark، نويسنده , , S.Y and Badan، نويسنده , , M and Beltramin، نويسنده , , A and Bertazzo، نويسنده , , E. Preciso، نويسنده , , R and Stivanello، نويسنده , , F and Bisoffi، نويسنده , , G and Boscagli، نويسنده , , L and Carlucci، نويسنده , , D and Dainelli، نويسنده , , A and Fortuna، نويسنده , , G and Gustafsson، نويسنده , , S and Lombardi، نويسنده , , A ، نويسنده ,
Abstract :
Quarter Wave Resonators (QWRs) can be fabricated by sputtering a niobium thin film onto an OFHC copper base. After a deep investigation of DC biased diode sputtering in cylindrical configuration, the coating procedure has become well-established for the cavities of the LNL ALPI-linac 0.14 beta section and it is under progressive improvement for lower beta cavities. A first cryogenic module with four sputtered QWRs was installed in ALPI. All resonators sputtered during laboratory tests provided Q-values of the order of 109 and accelerating fields around 7 MV/m at 7 W. Accelerating field values up to 4.2 MV/m are instead achieved by the four resonators installed along the beam line. This shows that severe attention should be paid to the installation procedure into a real accelerating machine and that further study is needed for a future serial production.
