نتایج جستجو برای: photon fluence
تعداد نتایج: 74287 فیلتر نتایج به سال:
Introduction: Gamma cameras are proposed for online range verification and treatment monitoring in proton therapy. An Analytical formula was derived and validated for sensitivity of a slit collimator based on the photon fluence concept. Methods: Fluence formulation was generalized for photons distribution function and solved for high-energy point sources. The...
Photon dose calculation algorithms (such as the pencil beam and collapsed cone, CC) model the attenuation of a primary photon beam in media other than water, by using pathlength scaling based on the relative mass density of the media to water. In this study, we assess if differences in the electron density between the water and media, with different atomic composition, can influence the accurac...
Hexagonal boron nitride is a promising material of modern optoelectronics. Point defects in this can serve as single-photon sources. In paper we investigate the modification luminescent properties hexagonal by means local irradiation with focused gallium and helium ion beams. It demonstrated that intensity band-to-band cathodoluminescence monotonically decreases increasing fluence for both heli...
For most optoelectronic applications of graphene, a thorough understanding of the processes that govern energy relaxation of photoexcited carriers is essential. The ultrafast energy relaxation in graphene occurs through two competing pathways: carrier-carrier scattering, creating an elevated carrier temperature, and optical phonon emission. At present, it is not clear what determines the domina...
CTmod - A toolkit for Monte Carlo simulation of projections including scatter in computed tomography
The CTmod toolkit is a set of C++ class libraries based on the CERN's application development framework ROOT. It uses the Monte Carlo method to simulate energy imparted to a CT-scanner detector array. Photons with a given angle-energy distribution are emitted from the X-ray tube approximated by a point source, transported through a phantom, and their contribution to the energy imparted per unit...
We reconstructed the 3D Fourier intensity distribution of monodisperse prolate nanoparticles using single-shot 2D coherent diffraction patterns collected at DESY's FLASH facility when a bright, coherent, ultrafast x-ray pulse intercepted individual particles of random, unmeasured orientations. This first experimental demonstration of cryptotomography extended the expansion-maximization-compress...
We report what is to our knowledge the first photochemical fabrication of a long-period grating in a pure-fused-silica photonic crystal fiber. The inscription technique is based on a two-photon absorption mechanism and does not require a specially designed photonic crystal fiber with a photosensitive Ge-doped core. The characteristic fluence value for the inscription is an order of magnitude le...
BackgroundOne of the most significant Intensity Modulated Radiation Therapy treatment benefits is a high target to normal tissue dose ratio. To improve this advantage, an additional accessory such as a compensator is used to delivering doses. Compensator-based IMRT treatment is usually operated with an energy higher than 10 MV. Photoneutrons, which have high linear energy transfer and radiobiol...
Background and Aim: Liposuction is one of the most popular procedures for removing unwanted body fat deposits now. The conventional methods for liposuction however have many drawbacks among them is long recovery time, scars, bruising, skin flaccidity and excessive blood loss. Considering the increasing demand for body sculpting, the need to improve these techniques is of vital importance. ...
background: monte carlo (mc) modeling of a linear accelerator is a prerequisite for monte carlo dose calculations in external beam radiotherapy. in this study, a simple and efficient model was developed for elekta sl-25 linear accelerator using mcnp4c monte carlo code materials and methods: the head of elekta sl-25 linac was simulated for 6 and 18 mv photon beams using mcnp4c mc code. energy sp...
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