Gordon B. Bowden

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Acknowledgements We would like to acknowledge the support and guidance of the International Committee on Future Accelerators (ICFA), chaired by A. Wagner of DESY, and the International Linear Collider Steering Committee (ILCSC), chaired by S. Kurokawa of KEK, who established the ILC Global Design Effort, as well as the World Wide Study of the Physics and(More)
The SLAC Linac can deliver to End Station A (ESA) a high-energy test beam with similar beam parameters as for the International Linear Collider (ILC) for bunch charge, bunch length and bunch energy spread.[1] ESA beam tests run parasitically with PEP-II with single damped bunches at 10Hz, beam energy of 28.5 GeV and bunch charge of (1.5-2.0)·10 10(More)
The linacs proposed for the Next Linear Collider (NLC) and Japanese Linear Col-lider (JLC) would contain several thousand X-Band accelerator structures that would operate at a loaded gradient of 50 MV/m. An extensive experimental and theoretical program is underway at SLAC, FNAL and KEK to develop structures that reliably operate at this gradient. The(More)
A system for characterizing the phase shift per cell of a long X-band accelerator structure is described. The fields within the structure are perturbed by a small cylindrical metal bead pulled along the axis. A computer controls the bead position and processes the data from a network analy-zer connected to the accelerator section. Measurements made on(More)
We present a new approach to multimodal systems development that enables end-user applications to present information in alternative modalities, thereby making them useful even in situations where the default output modality is unacceptable to the user. We discuss the implementation of a software framework for constructing multimodal applications using the(More)
There are many challenges in the design of the normal-conducting portion of the ILC positron injector system such as achieving adequate cooling with the high RF and particle loss heating, and sustaining high accelerator gradients during millisecond-long pulses in a strong magnetic field. The proposed design for the positron injector contains both(More)
One of the possible limitations to achieving high power in RF structures is damage to metal surfaces due to RF pulsed heating. Such damage may lead to degradation of RF performance. An experiment to study RF pulsed heating on copper has been developed at SLAC. The experiment consists of operating two pillbox cavities in the TE 011 mode using a 50 MW X-Band(More)
Fundamental power couplers for superconducting accelerator applications like the ILC are complicated transmission line assemblies that must simultaneously accommodate demanding RF power, cryogenic, and cleanliness constraints. When these couplers are RF conditioned, the observed response is an aggregate of all the parts of the coupler and the specific(More)
As a joint effort in the JLC/NLC research program, we have developed a new type of damped detuned accelerator structure with optimized round-shaped cavities (RDDS). This paper discusses some important R&D aspects of the first structure in this series (RDDS1). The design aspects covered are the cell design with sub-MHz precision, HOM detuning, coupling and(More)
Due to the extremely high energy deposition from positrons, electrons, photons and neutrons behind the positron target, and because a solenoid is required to focus the large emittance positron beam, the 1.3 GHz pre-accelerator has to use normal conducting structures up to energy of 400 MeV. There are many challenges in the design of the normal-conducting(More)