In the paper, the geometrical parameters and energetics of the extremely narrow pseudo-nondiffracting beams with the spot size of several micrometers are examined. The main attention is focused on design, realization and testing of the set-up enabling conversion of the laser diode beam or the fiber mode to the narrow Bessel-Gauss beam whose spot can be continuously relocated across the plane pe...

For the acceptance test and annual quality assurance of the Leksell Gamma Unit, measurement of the beam accuracy, defined as a distance between mechanical and radiological isocenters, poses a challenge to medical physicists. The specification for the beam accuracy is within 0.5 mm for the 4-mm collimator helmet. In this report, we introduce a simple technique to analyze the beam accuracy by usi...

Crossed molecular beam scattering experiments in which the energy of the collision is varied can reveal valuable insight into the collision dynamics. The energy resolution that can be obtained depends mainly on the velocity and angular spreads of the molecular beams; often, these are too broad to resolve narrow features in the cross sections like scattering resonances. The collision energy reso...

Fast realistic rendering of objects in scattering media is still a challenging topic in computer graphics. In presence of participating media, a light beam is repeatedly scattered by media particles, changing direction and getting spread out. Explicitly evaluating this beam distribution would enable efficient simulation of multiple scattering events without involving costly stochastic methods. ...

Background: This study aims to investigate radiation beam geometry of Cyberknife beam and change in dosimetric characteristics of six megavoltage (6MV) flattening filter free (FFF) beam after passing through high density cadmium free compensator alloy.Material and Methods: In this experimental study, changes in FFF beam dosimetric characteristics after passing through compensator alloy wa...

We adopt the Echo-Enabled Harmonic Generation (EEHG) scheme proposed by D. Xiang to design a device to generate intense narrow-band THz radiation based on the Tsinghua Thomson scattering X-ray (TTX) electron beam [1]. In this scheme the 50 MeV electron beam is firstly energy-modulated by two lasers with wavelengths of 800nm and 1560nm respectively. Then the modulated electron beam is sent into ...