A micrometer-scale “plasma lens” self-constructed by the prepulse and main pulse of Laguerre–Gaussian (LG) laser is realized to enhance collimation acceleration proton beams in a target normal sheath field mechanism. Hydrodynamic FLASH particle-in-cell simulations are carried out find that collimated source with beam divergence ∼2.7° generated LG laser, which smaller than case driven traditiona...

1 Introduction In high-energy physics colliders, the 'halo' particles surrounding the core of the beams would cause intolerable background in the physics detectors if not removed. Collima-tion systems consisting of mechanical 'spoilers' on the order of a radiation length are placed close to the beam and used to 'scrape' the halo particles off: the particles scattered by the spoilers are then co...

The collimation C of a hadronic event in the e + e −-annihilation is defined as the average of cos θ, C =< cos θ >, where θ is the angle of each hadron measured from the thrust axis, and the average is over all the hadrons produced in an event. It is an infrared-stable event-shape parameter. 1−C, the difference between the unity and the average collimation at a given energy, is proportional to ...

The authors theoretically and numerically investigate the beam propagation near the supercollimation frequency s 0 in a photonic crystal made of nonlinear material. Since the value and sign of the equal-frequency-contour curvature which dominates the beam behaviors can be nonlinearly tuned near s , a kind of nonlinear effect is generated. The envelope equation with unique form is also obtained....

Based on realistic Monte-Carlo simulations a two-stage beam collimation system is designed to minimize the beam loss in the Fermilab Tevatron for fixed target and collider Run II. Thin primary collimators are used to increase particle amplitude and their impact parameter on the downstream secondary collimators. This results in a significant reduction of the total beam loss in the machine, decre...

Experience with the SLC has indicated that backgrounds caused by the tails of the transverse beam distribution will be a serious problem for a next generation linear collider. Mechanical scrapers may not provide the best solution, because they may be damaged by the tiny, intense beams, and dso because they may induce wakeiIeld kicks large enough to cause emittance dilution. In this paper, we pr...