C. ADOLPHSEN, W. BAUMGARTNER, K. JOBE, R. LOEWEN, D. McCORMICK, M. ROSS, J.W. WANG (SLAC)
During its initial phase of operation, the linacs of the NLC will contain roughly 5000, 1.8 m long X-Band accelerator structures that will accelerate beams of electrons and positrons to 250 GeV. These structures will be powered with 170 MW, 380 ns long rf pulses that will produce an average unloaded gradient of 72 MV/m in the structures. As part of the R&D effort for the NLC, a number of prototype structures have been built and operated at the Next Linear Collider Test Accelerator (NLCTA) at SLAC. Here we have been studying the rf processing characteristics and operational stability of these structures at high gradients. Significant progress was made during the past year after our power sources were upgraded to reliably produce the required NLC power levels and beyond. In this paper, we describe the processing methodology and present results from several structures on processing rates, breakdown characteristics, dark currents and beam-based phase advance measurements.
* Work supported by Department of Energy contract DE-AC03-76SF00515
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