Investigation of Niobium Surface Roughness and Hydrogen Content with Different Polishing Conditions for Performance Recovery of Superconducting QWRs in JAEA Tokai-Tandem Accelerator

The effect of the different polishing conditions for niobium has been investigated as basic data superconducting quarter-wave resonators (QWRs) in booster linac Tokai-tandem accelerator. Surface roughness and desorbed hydrogen amount samples with such method (electropolishing: EP or chemical polishing: CP), thickness, electrode location, have measured. For measurement, thermal desorption spectroscopy performed. arrangement to avoid bubbles hitting surface is found be important obtain a smooth less content. large thickness resulted content case both CP. without appropriate polished will best solution actual QWRs.