Fabrication techniques and RF properties of niobium thin wall cavities

Cavities with the designed resonant frequency of 2856 MHz and a wall thickness of 0.42 mm were fabricated by YAG laser welding. Pulsed RF properties of the single-cell cavities were measured. To obtain cavity Q values, the evaporation rate of liquid He was measured. The maximum values of the peak surface fields were 67 MV/m with a measured Q/sub 0/ of 4*10/sup 5/ at the input pulse width of 6 mu s and 57 MV/m with 3*10/sup 5/ at 10 mu s. The properties changed at an input power of 400 kW, Q/sub 0/ of 1.5*10/sup 6/, and a peak field of 50 MV/m.<
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