In this paper we present an automatic system developed for the Lisbon’s Technologic Nuclear Institute to control the operation of their particle accelerator. It is an accelerator based on a Van de Graaff machine. The system uses a personal computer running LabVIEW software which implements the procedures to automatically increase the terminal voltage, light-up the ion source and focus the parti...

In this research, a functionally graded microbeam bonded with piezoelectric layers is analyzed under electric force. Static and dynamic instability due to the electric actuation is studied because of its importance in micro electro mechanical systems, especially in micro switches. In order to prevent pull-in instability, two piezoelectric layers are used as sensor and actuator. A current amplif...

The electromagnetic wake field response of a hollow plasma channel to a driver (laser or charged particle beam) of arbitrary velocity is derived. The dispersion and loss factors of excited fundamental and higher order azimuthal modes are computed. Growth rates for beam breakup instabilities are calculated and beam transport is studied. External focusing is shown to provide a method of controlli...

In this paper, free and forced vibration of simply-supported Single-walled carbon nanotube is investigated under the moving nanoparticle by considering nonlocal cylindrical shell model. To validate the theoretical results, modal analysis of nanotube is conducted using ANSYS commercial software. Excellent agreement is exhibited between the results of two different methods. Furthermore, the dynam...

Over the past decade, extensive simulations of beam-beam effects in e+e− colliders, based on the particle-in-cell method, were developed to explain many complex experimental observations. Recently, such simulations were used to predict the future luminosity performance of e+e− colliders. Some predictions have been proven to be correct in the existing accelerators. In this paper, many effects su...

An intense, high-energy electron or positron beam can have focused intensities rivaling those of today’s most powerful laser beams. For example, the 5 ps ~full-width, half-maximum!, 50 GeV beam at the Stanford Linear Accelerator Center ~SLAC! at 1 kA and focused to a 3 micron rms spot size gives intensities of .10 W/cm at a repetition rate of .10 Hz. Unlike a ps or fs laser pulse which interact...

the present study is the first to analyze the dynamic response of a poroelastic beam subjected to a moving force. moreover, the influences of attached mass-spring systems and non-ideal supports (with local movements in the supporting points or base due to the presence of factors such as gaps, unbalanced masses, and friction or seismic excitations) on the responses were investigated. non-ideal s...

Experiments to study the light emission from plasma produced by particle beams are presented. Fundamental aspects in comparison with discharge plasma formation are discussed. It is shown that the formation of excimer molecules is an important process. This paper summarizes various studies of particle beam induced light emission and presents the first results of a direct comparison of light emis...

We report the first observation of the simultaneous three-dimensional confinement of both a low-index particle and a high-index particle within a single-beam optical trap by using a strongly focused laser beam containing an optical vortex. Experimental and theoretical investigations of the trap stability are described. © 1999 Optical Society of America [S0740-3224(99)00904-2] OCIS codes: 140.70...