BACKGROUND AND PURPOSE To investigate combining unmodulated electron beams with intensity-modulated radiation therapy to improve dose distributions for superficial head and neck cancers, and to compare mixed beam plans with helical tomotherapy. MATERIALS AND METHODS Mixed beam and helical tomotherapy dose plans were developed for two patients with parotid gland tumors and two patients with na...

An interesting and satisfactory fluid model has been proposed in literature for the the description of relativistic electron beams. It was obtained with 14 independent variables by imposing the entropy principle and the relativity principle. Here the case is considered with an arbitrary number of independent variables, still satisfying the above mentioned two principles; these lead to condition...

K E Y W O R D S SEM, electron beam induced current, EBIC, REBIC, grain boundaries, electroceramics,

We present results of measurements of spot size and angular divergence of a 30 GeV electron beam though use of optical transition radiation (OTR). The OTR near field pattern and far field distribution are measured as a function of beam spot size and divergence at wavelengths of 441, 532, and 800 nm, for both the single and double foil configurations. Electron beam spot sizes of 50μm rms have be...

Electron beam welding (EBW) shows certain problems with the control of focus regime. The electron beam focus can be controlled in electron-beam welding based on the parameters of a secondary signal. In this case, the parameters like secondary emissions and focus coil current have extreme relationships. There are two values of focus coil current which provide equal value signal parameters. There...

Intense ion beams are difficult to maintain as non-neutral plasmas. Experiments and simulations are used to study the complex interactions between beam ions and unwanted electrons. Such “electron clouds” limit the performance of many accelerators. To characterize electron clouds, a number of parameters are measured, including total and local electron production and loss for each of three major ...

This article summarizes the 13th ICFA Beam Dynamics Mini-Workshop Beam-Induced Pressure Rise in Rings (BNL, Dec. 9-12, 2003) [1]. BACKGROUND OF WORKSHOP Beam induced pressure rise was an intensity limit at CERN ISR during the early 1970's. The beam gas ionization created pressure rise caused more gas ionization, resulting in pressure run-away at high beam intensity. Extensive baking, chamber tr...