this paper presents a finite element analysis and its related experimental test of corrugated steel web beams subjected to fatigue loading. a particular focus in this study was set on the fatigue failure arising from the web-to-flange welded joint of the corrugated steel web beam. a detailed three-dimensional finite element model which explicitly includes the geometry of the web-to-flange welds...

We analyze the excitation of an arbitrary, externally coupled resonant structure by a charged particle beam, providing a rigorous formulation of the effect of spurious modes and intrinsic mode nonlinearity on inferred beam coordinates. Results are illustrated for a two-cavity system employed for beam-position monitoring with an idealized front-end signal processor. © 1999 American Institute of ...

In this Letter we propose the concept of the evanescent Airy beam. We analyze the structure of the ideal evanescent Airy beam, which initial profile has the Airy form, while the spectral decomposition consists of only evanescent partial waves. Also, we discuss the refraction of the Airy beam through the interface and investigate the field of the transmitted evanescent Airy beam. c © 2009 Optica...

One of the latest serious problems for KEKB is a beam size blow up of the positron beam. The blow up is considered to be caused by a single-beam instability due to an electron cloud around the positron beam. The seed of the electrons is mainly photoelectrons emitted from the surface of vacuum chamber. Here a surface with a sawtooth structure is proposed to reduce the photoelectron yield. Experi...

It is shown herein that the energy spread of order one percent in the beam train in the NLC can suppress the emittance growth due to structure misalignments and initial jitter E ect of Energy Spread in the Beam Train on Beam Breakup Instability G. V. Stupakov September 20, 1999

The preservation of beam quality along the UNILAC Alvarez DTL section is a major concern with respect to the availability of the design beam parameters for FAIR. The DTL comprises 177 accelerating gaps and 184 quadrupoles for transverse beam focusing. They form a periodic structure of linear elements. The high beam currents needed for FAIR arise non-linear space forces leading to emittance grow...