we derive error estimates in the appropriate norms, for the streamlinediffusion (sd) finite element methods for steady state, energy dependent,fermi equation in three space dimensions. these estimates yield optimal convergencerates due to the maximal available regularity of the exact solution.high order sd method together with implicit integration are used. the formulationis strongly consistent...

We present a new concept for a beam position monitor with the unique ability to map particle beam position to a measurable wavelength. Coupled with an optical spectrograph, this beam position monitor is capable of subnanometer resolution. We describe one possible design, and through finite-element frequency-domain simulations, we show a resolution of 0.7 nm. Because of its high precision and ul...

In light of the success of 3D printing using fused-deposition modeling or higher-resolution variants with lasers applicable to polymers and metals, one may wonder whether an analogous approach exists on the nanometer scale. Indeed it does. With the aid of focused particle beam-induced deposition (FPBID) it is possible to create solid-state structures on the nanoscale. However, in contrast with ...

The co-propagation of an intense particle beam with an ionizing laser beam in a working gas/plasma is considered. When the axes of the laser and particle beam are not aligned, then asymmetric plasma lensing results in a net dipole "eld acting on the particle beam. The particle beam can be steered or bent (as well as focused) by steering the laser. An analogy is made between the bending of the p...

crack identification is a very important issue in mechanical systems, because it is a damage that if develops may cause catastrophic failure. in the first part of this research, modal analysis of a multi-cracked variable cross-section beam is done using finite element method. then, the obtained results are validated usingthe results of experimental modal analysis tests. in the next part, a nove...

In this paper we present a study of beam halo based on a three-dimensional particle-core model of an ellipsoidal bunched beam in a constant focusing channel. For an initially mismatched beam, three linear envelope modes – a high frequency mode, a low frequency mode and a quadrupole mode – are identified. Stroboscopic plots are obtained for particle motion in the three modes. With higher focusin...

An investigation of the beam-beam interaction as a function of transverse separation of colliding proton and antiproton bunches is presented. A mathematical model describing resonant excitation of separated beams is examined. Beam-beam experiments in the Fermilab collider measure beam-beam resonant excitation ~particle losses! at different transverse beam separations in the storage ring. The ex...