A physical model for the simulation of x-ray emission spectra from samples irradiated with kilovolt electron beams is proposed. Inner shell ionization by electron impact is described by means of total cross sections evaluated from an optical-data model. A double differential cross section is proposed for bremsstrahlung emission, which reproduces the radiative stopping powers derived from the pa...

The advent of a next linear e e collider and back-scatterd laser beams will allow the study of a vast array of high energy processes of the Standard Model through the fusion of real and virtual photons and other gauge bosons. As examples, I discuss virtual photon scattering ! X in the region dominated by BFKL hard Pomeron exchange and report the predicted cross sections at present and future e ...

We outline a rigorous method which can be used to solve the many-body Schrödinger equation for a Coulomb interacting electronic system in an external classical magnetic field as well as a quantized electromagnetic field. Effects of the geometry of the electronic system as well as the polarization of the quantized electromagnetic field are explicitly taken into account. We accomplish this by per...

Introduction:  Skin  sparing  is  one  of  the  most  desirable  characteristics  of  high  energy  photon  beams. However, the photons emerging from the target of linacs are contaminated by secondary  electrons  as  a  result  of  their  interactions  with  air,  collimators,  flattening  filter  and  any  other  objects in their path. This phenomenon tends to increase the skin dose received b...

We present the results of a numerical calculation of the photon splitting rate below the electron-pair creation threshold (ω ≤ 2m) in magnetic fields B > ∼ B cr = m 2 /e = 4.414 × 10 9 T. Our results confirm asymptotic approximations derived in the low-field (B < B cr) and high-field (B ≫ B cr) limit, and allow interpolating between the two asymptotic regions. Our expression for the photon spli...

A protocol is prescribed for clinical reference dosimetry of external beam radiation therapy using photon beams with nominal energies between 60Co and 50 MV and electron beams with nominal energies between 4 and 50 MeV. The protocol was written by Task Group 51 (TG-51) of the Radiation Therapy Committee of the American Association of Physicists in Medicine (AAPM) and has been formally approved ...

Characteristics of electron-cooled bunched ion beams have been studied using the particle-tracking simulation in which the space-charge force and the force induced through the transverse broadband impedance are taken into account. The beams become space-charge dominated during the bunching of coasting beams. The simulation results show that the beams meet the transverse instability which can be...

Introduction: The aim of this study was to investigate the initial electron beam parameters for Monte Carlo model of 6MV photon beam produced by Siemens Oncor® linear accelerator.   Materials and Methods: In this study, the EGSnrc Monte Carlo user codes BEAMnrc and DOSXYZnrc were used. The beamnrc code were used for modelling of a 6 MV photon beam produced by...