2,449 research outputs found
Simulation of beam steering phenomena in bent crystals
The simulation methods for the channeling phenomena in GeV/TeV energy range
in ideal or distorted crystal lattices are discussed. Monte Carlo predictions
for feed-out and feed-in rates, dislocation dechanneling, and deflection
efficiencies of bent crystals are compared to the experimental data. The role
of multiple interactions with crystal in circular accelerators ("multipass
channeling") for the efficiency boost in the crystal-aided extraction
experiments is analysed. Possible future applications of the crystal channeling
technique are considered.Comment: 10pp. Presented at COSIRES 1998 (Okayama
The theory of the scattering-induced feeding-in in bent crystals
An analytical theory for the efficiency of scattering-induced transitions
from a random to a channeled state (feed-in) in bent crystals is derived. The
predictions from the theory are in good agreement with experiment and Monte
Carlo simulations.Comment: 6 page
The limits of volume reflection in bent crystals
We show that theory predictions for volume reflection in bent crystals agree
with recent experimental data. This makes possible to predict volume reflection
angle and efficiency in a broad range of energy for various crystals. A simple
formula is proposed for volume reflection efficiency. We derive the physical
limits for application of crystal reflection at high-energy accelerators where
it may help beam collimation.Comment: 6 pages, 2 figure
Optimization of crystal extraction experiment
Using a computer model for the crystal extraction, we investigate the
bent-crystal parameters optimal for the extraction experiment. The optimal
crystal curvature is found to be near 1 GeV/cm (for pv/R), i.e. a factor of
2--3 higher than for the crystal application in beam lines. An influence of the
accelerator optics on extraction is discussed. A possibility of using the
high-Z crystals for extraction is considered. The simulations for the ongoing
experiments at the CERN-SPS and the Fermilab Tevatron, and for the proposed
extraction at LHC, are presented.Comment: 11 pages, 4 figure
Studies of Nanotube Channeling for Efficient Beam Scraping at Accelerators
While particle beam steering (and in particular, "scraping") in accelerators
by bent channeling crystals is an established technique extensively tested at
IHEP Protvino and other major high-energy labs, an interesting question is how
one could improve channeling capabilities by applying modern nanotechnology.
Theoretical research of nanotube channeling was in progress over recent years.
In this work, we assess potential benefits from nanotube channeling for real
accelerator systems. We report simulation studies of channeling in
nanostructured material (carbon SWNT and MWNT) tested for possible serving as a
primary scraper for the collimation systems of hadron colliders. The advantages
of nanostructured material as a potential choice for a primary scraper in a
high-energy accelerator such as LHC or the Tevatron are discussed in comparison
to crystal lattices and amorphous material. We evaluate physical processes
relevant to this application and reveal nanotechnology requirements.Comment: Presented at the Int. Conf. on Atomic Collisions with Solids
(ICACS-21, Genova 4-9 July 2004
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