arXiv subjects

G. B. Bowden

Publications and source records attributed to G. B. Bowden.

4 recordsLinked to original sources

arXiv2003

Transverse Impedance Bench Measurements in NLC/JLC Accelerating Structures

The wire method is a more rapid and less costly method to measure impedances of RF components compared to methods using a beam. A setup using a single displaced wire to excite and measure transverse resonant modes in accelerating structures for the Next Linear Collider/ Japanese Linear Collider (NLC/JLC) has been built. The RF signal is coupled into and out of the structure using two matching sections with a broadband frequency from 11 to 18 GHz. Their contribution to the scattering parameter is minimized by a calibration technique. A standing wave structure has been measured. Difficulties in accurately predicting the modal loss factors were encountered related to the approximations made and to experimental issues. The measurements are presented and comparisons with simulations are made.

physics.acc-ph↗

arXiv2002

Impedance Measurement Setup for Higher-Order Mode Studies in NLC Accelerator Structures with the Wire Method

Dipole modes are the main cause of transverse emittance dilution in the Japanese Linear Collider / Next Linear Collider (JLC/NLC). A diagnostic setup has been built in order to investigate them. The method is based on using a coaxial wire to excite and measure electromagnetic modes of accelerating structures. This method can offer a more efficient and less expensive procedure than the ASSET facility. Initial measurements have been made and are presented in this paper.

physics.acc-ph↗

arXiv2002

Coaxial Wire Measurements In NLC Accelerating Structures

The coaxial wire method provides an experimental way of measuring wake fields without the need for a particle beam. A special setup has been designed and is in the process of being fabricated at SLAC to measure the loss factors and synchronous frequencies of dipole modes in both traveling and standing wave structures for the Next Linear Collider (NLC). The method is described and predictions based on electromagnetic field simulations are discussed

physics.acc-ph↗

arXiv2000

Design, fabrication and measurement of the first rounded damped detuned accelerator structure (RDDS1)

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 damping technique and wakefield simulation. The fabrication issues covered are ultra-precision cell machining with micron accuracy, assembly and diffusion bonding technologies to satisfactorily meet bookshelf, straightness and cell rotational alignment requirements. The measurements described are the RF properties of single cavities and complete accelerator section, as well as wakefields from the ASSET tests at SLAC. Finally, future improvements are also discussed.

physics.acc-ph↗