• F.S. He, J.K. Hao, F. Wang, W. Xu, B.C. Zhang, K. Zhao
  PKU/IHIP, Beijing

Funding: Supported by National Basic Research Program(No. 2002CB713600) and NSFC(No. 10775010).

The 3.5-cell cavity for the PKU DCSC photoinjector requires the main coupler and the pickup be on the same side of the cavity, which will cause crosstalk between them. At room temperature, serious distortion of the RF response is caused. This paper applies a clear understanding of the RF signal; numerical and experimental study shows that the crosstalk will be negligible in superconducting (SC) status. Furthermore, a method to calculater resonant frequency and loaded quality factor from the crosstalk signal is provided

• F. Wang, C. Adolphsen
  SLAC, Menlo Park, California

Funding: Work supported by the DOE under contract DE-AC02-76SF00515

An L-band (1.3 GHz), normal-conducting, five-cell, standing-wave cavity that was built as a prototype capture accelerator for the ILC is being high-power processed at SLAC. The goal is to demonstrate stable operation at 15 MV/m with 1 msec, 5 Hz pulses and the cavity immersed in a 0.5 T solenoidal magnetic field. This paper summarizes the performance that was ultimately achieved and describes a novel analysis of the modal content of the stored energy in the cavity after a breakdown to determine on which iris it occurred.

• C. Adolphsen, A.A. Haase, D. Kiehl, C.D. Nantista, T.N. Nieland, J. Tice, F. Wang
  SLAC, Menlo Park, California

Funding: Work supported by the DOE under contract DE-AC02-76SF00515

A new facility to clean, assemble, bake and rf process TTF3-style power couplers has been completed and is in operation at SLAC. This facility includes a class-10 cleanroom, bake station and an L-band source capable of producing up to 4 MW pulses. This paper describes the facility, test results from processing pairs of couplers that will be used in cryomodules at FNAL, and efforts to simplify the design and manufacturing of the couplers for large scale use at ILC. Also, tests of the couplers to explore their power limits for use in an FNAL superconducting proton linac are presented.

• C. Adolphsen, G.B. Bowden, V.A. Dolgashev, L. Laurent, S.G. Tantawi, F. Wang, J.W. Wang
  SLAC, Menlo Park, California
• S. Döbert, A. Grudiev, G. Riddone, W. Wuensch, R. Zennaro
  CERN, Geneva
• Y. Higashi, T. Higo
  KEK, Ibaraki

Funding: Work supported by the DOE under contract DE-AC02-76SF00515

As part of a SLAC-CERN-KEK collaboration on high gradient X-band structure research, several prototype structures for the CLIC linear collider study have been tested using two of the high power (300 MW) X-band rf stations in the NLCTA facility at SLAC. These structures differ in terms of their manufacturing (brazed disks and clamped quadrants), gradient profile (amount by which the gradient increases along the structure which optimizes efficiency and maximizes sustainable gradient) and HOM damping (use of slots or waveguides to rapidly dissipate dipole mode energy). The CLIC goal in the next few years is to demonstrate the feasibility of a CLIC-ready baseline design and to investigate alternatives which could bring even higher efficiency. This paper summarizes the high gradient test results from the NLCTA in support of this effort.