The filamentation instability driven by two spatially uniform and counterstreaming beams of charged particles in plasmas is modelled by a particle-in-cell (PIC) simulation. Each beam consists of the electrons and positrons. The four species are equally dense and they have the same temperature. The one-dimensional simulation direction is orthogonal to the beam velocity vector. The magnetic field...

Desktop laser plasma acceleration has proven to be able to generate gigaelectronvolt-level quasi-monoenergetic electron beams. Moreover, such electron beams can oscillate transversely (wiggling motion) in the laser-produced plasma bubble/channel and emit collimated ultrashort X-ray flashes known as betatron radiation with photon energy ranging from kiloelectronvolts to megaelectronvolts. This i...

introduction radiotherapy planning systems require many percentage depth dose (pdd) and profile measurements and there are various dosimeters that can be used to obtain these scans. as dose perturbation is particularly troublesome in smaller photon fields, using a low-perturbation, unshielded electron field diode (efd) in these fields is of interest. the aim of this work was to investigate the ...

Radiation pneumonitis is a well-documented side effect of radiation therapy for breast cancer. The purpose of this study was to compare combined photon-electron, photon-only, and electron-only plans in the radiation treatment of the supraclavicular lymph nodes. In total, 13 patients requiring chest wall and supraclavicular nodal irradiation were planned retrospectively using combined photon-ele...

A procedure is described to extract beams from specially tailored electron plasmas in a Penning-Malmberg trap in a 4.8 T field. Transport to 1 mT is followed by extraction from the magnetic field and electrostatic focusing. Potential applications to positron beams are discussed.

Treating shallow tumors with a homogeneous dose while simultaneously minimizing the dose to distal critical organs remains a challenge in radiotherapy. One promising approach is modulated electron radiotherapy (MERT). Due to the scattering properties of electron beams, the commercially provided secondary and tertiary photon collimation systems are not conducive for electron beam delivery when s...

Singularities in wave fields, such as phase vortices, are of substantial interest for light optics, matter waves and x-ray optics. New theoretical insights [1] and cutting edge nanofabrication techniques have recently created a wide variety of electron vortex beams [2, 3] for the transmission electron microscope (TEM), which can provide spectroscopic information pertaining to the magnetic prope...