The possibility of increasing the apertures of the LCLS gas attenuator/gas detector system is considered. It is shown that increase of the apertures from 3 to 6 mm, together with 4fold reduction of the operation pressure does not adversely affect the vacuum conditions upstream or downstream. No change of the pump speed and the lengths of the differential pumping cells is required. One minor mod...

We demonstrate a novel high-resolution portable beam profiler based on a slanted linear array of small apertures, termed a slanted hole array beam profiler (SHArP). The apertures are directly fabricated on a metal-coated CMOS imaging sensor. With a single linear scan, the aperture array can establish a virtual grid of sampling points for beam profiling. With our prototype, we demonstrate beam p...

We propose a method to obtain improved expressions for the diffraction of circular apertures in boundary between near and far field. The is based on an analysis center value pattern derived from Fresnel expression. shown be applied both amplitude, phase, complex apertures, compared propagation simulations. show how these new allow use Fraunhofer approximation at numbers least twice as large con...

An H-shaped nano-aperture used as a high efficient near-field radiator is demonstrated. The transfer efficiency higher than unity and nanoscale radiation spot can be achieved simultaneously in the near field compared with regular apertures. The radiation enhancement is ascribed to the fundamental electric–magnetic field propagating in the TE10 mode concentrated in the gap between the ridges, wh...

Coded aperture imaging systems have recently shown great success in recovering scene depth and extending the depth-of-field. The ideal pattern, however, would have to serve two conflicting purposes: 1) be broadband to ensure robust deconvolution and 2) has sufficient zero-crossings for a high depth discrepancy. This paper presents a simple but effective scene-adaptive coded aperture solution to...

At an intermediate stage of radiation treatment planning for IMRT, most commercial treatment planning systems for IMRT generate intensity maps that describe the grid of beamlet intensities for each beam angle. Intensity map segmentation of the matrix of individual beamlet intensities into a set of MLC apertures and corresponding intensities is then required in order to produce an actual radiati...

OBJECTIVES The objectives were to measure the impact of specific features of imaging devices on tasks relevant to minimally invasive surgery (MIS) and to investigate cognitive and perceptual factors in such tasks. BACKGROUND Although image-guided interventions used in MIS provide benefits for patients, they pose drawbacks for surgeons, including degraded depth perception and reduced field of ...

Finite Difference Time Domain (FDTD) is applied to study the characteristics of electromagnetic interference for power plane-battery management system (PP-BMS) enclosure, for modeling the coupling of an incident electromagnetic pulse (EMP) with a conducting wire through a BMS enclosure and aperture on it. Simulation and analysis are done by radius of the wires, incidence angles of EMP in the co...

We investigate the influence of localized and propagating surface plasmons on third harmonic generation from rectangular apertures in metal films. We designed optimal aperture array structures by using finite-difference time-domain simulations with nonlinear scattering theory. From this design space, we fabricated and measured the third harmonic in the region of maximal performance. We find the...