A novel concept of controlled halo removal for intense high-energy beams in storage rings and colliders is presented. It is based on the interaction of the circulating beam with a 5-keV, magnetically confined, pulsed hollow electron beam in a 2-m-long section of the ring. The electrons enclose the circulating beam, kicking halo particles transversely and leaving the beam core unperturbed. By ac...

Several schemes for checking collimation of a light beam based on the self-imaging (Talbot effect) combined with the moire technique have been described. When a grating is illuminated by a collimated beam of monochromatic light, exact self-images of the grating are formed at certain welldefined planes perpendicular to the direction of the beam. The moire pattern is observed by placing an identi...

Intense ion beams with small phase space occupation (high brilliance) are mandatory to keep beam losses low in high current injector accelerators like those planned for the Facility for Antiproton and Ion Research (FAIR). The low energy beam transport from the ion source towards the linac has to keep the emittance growth low and has to support the optimization of the ion source tune. The Frankf...

The generation of highly collimated electron beams from a double-gate field emitter array with 40000 metallic tips and large collimation gate apertures is reported. Field emission beam measurements demonstrated the reduction of the beam envelope down to the array size by applying a negative potential to the on-chip gate electrode for the collimation of individual field emission beamlets. Owing ...

The Next Linear Collider accelerator will include a large (kilometer scale) and complex collimation system. The size and complexity of this system could be reduced if the collimator jaws could be made immune to damage from the electron beam. We describe two collimation systems currently under development. Construction of a prototype system which uses wheels that can be moved to a new position a...

We describe linac protection and a conventional collimation system appqxiate for a next linear collider. The linac accelerating structure can be protected from “worst credible failures” by a system of sacrificial spoilers. For the collimation system we consider the effects of asverse wakefields and the transmission, heating, mechanical stress, and edge-scattering properties of scrapers. We requ...

The use of a two stage crystal collimation system in the RHIC yellow ring is examined. The system includes a copper beam scraper and a bent silicon crystal. While scrapers were installed in both of the RHIC rings before the year 2000 run, the crystal is installed for the 2001 run in one ring only, forming a two stage collimation system there. We present simulations of the expected channeling th...

The cooling of molecules during the adiabatic expansion of supersonic seeded molecular beams is reviewed and illustrated by the example of NO -molecules. The reduction of the Doppler width by collimation of the beam and the cooling to low rotational temperatures brings a significant simplification of the complex NO -absorption spectrum and allows its assignment. The measured rotational tem...

Electron Lenses built and installed in Tevatron have proven themselves as safe and very reliable instruments which can be effectively used in hadron collider operation for a number of applications, including compensation of beam-beam effects [1], DC beam removal from abort gaps [2], as a diagnostic tool. In this presentation we – following original proposal [3] – consider in more detail a possi...