This paper studies the inverse problem of determining the shape and medium parameters of a smooth seafloor from sonar data. The first section of the paper reviews beamforming techniques and the Kirchhoff (high-frequency) approximation. The second section carries out a stationary phase calculation for various measurement configurations associated with side-scan sonar and pencil-beam sonar. These...

We study characteristic schemes for a model problem for the Fermi pencil beam equation. The objective is twofold: (i) To design eecient and accurate numerical schemes based on the principle of solving a particle transport problem, exactly, on each collision free spatial segment combined with a projection on each collision site, from a pre collision angle and energy coordinates (AE) to a post co...

BACKGROUND Scanned ion beam therapy of intra-fractionally moving tumors requires motion mitigation. GSI proposed beam tracking and performed several experimental studies to analyse the dosimetric precision of the system for scanned carbon beams. METHODS A beam tracking system has been developed and integrated in the scanned carbon ion beam therapy unit at GSI. The system adapts pencil beam po...

before inner-volume saturation (IVS), up-/downfield inversion for the metabolite cycling, and PRESS localization. They consist of a two dimensional selective excitation pulse exciting a pencil beam (r=30mm, l=120mm). Figure 1: Sagittal and axial T2 weighted turbo spinecho images of the cervical spinal cord showing the MRS voxel (red), the navigator (white), the innervolume saturation bands (blu...

Abstract A three-dimensional model of intense bunched beams is developed for cylindrical and corrugated conducting pipes. Updated comparisons between the current limits derived from this model and experimental data from PPM focusing klystrons are presented. An electrostatic Green’s function is formulated for azimuthally symmetric slowwave structures. Analytical and numerical results are present...