Low-energy antiproton channeling

doi:10.1016/0168-583X(90)90094-B

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

Volume 48, Issues 1–4, 2 March 1990, Pages 156-158

https://doi.org/10.1016/0168-583X(90)90094-B Get rights and content

Abstract

The Monte Carlo simulation method is used to calculate the energy spectra of 4 MeV antiprotons and protons following transmission through a 0.5 μm thick Si single crystal under axial channeling conditions. The characteristic features of the antiproton spectra associated with the possibility of the existence of finite trajectories in the transverse plane are discussed.

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Cited by (11)

Channeling of antiprotons
2003, Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
We present experimental results for channeling of 1.4 MeV antiprotons in a 0.5 μm thick $〈1 0 0〉$ silicon crystal. The ‘half-widths’ for the observed channeling effect, $Δ ψ_{p}$ , is significantly smaller than the Lindhard angle, ψ₁, as is the case for electrons where typical angles are about Δψ_e⁻≃0.6ψ₁. In the case of protons and positrons, critical angles are of the order Δψ_e⁺≃Δψ_p≃ψ₁. Thus, we may attribute the difference between $Δ ψ_{p,e^{−}}$ and Δψ_p,e⁺ to the sign of charge of the penetrating particle.
Influence of channeling on scattering of low-energy antiprotons transmitted through thin crystals
1994, Nuclear Inst. and Methods in Physics Research, B
A computer simulation study of the transmission of low-energy antiprotons through a thin single crystal, along one of the axial directions, is reported. The angular distribution of the scattered antiprotons behind the crystal is analysed. As an example the scattering of 300 keV antiprotons moving along the 〈110〉 axis in 500 Å and 2000 Å thick silicon crystal is considered. The results of the calculation show the formation of the ring-shaped patterns (doughnuts) for the incident angles of the order of the critical angle for channeling. A comparison of the angular distribution of antiprotons with that of protons is made. It is shown that the randomization of the transverse momentum is much quicker for antiprotons than for protons, which leads to a more uniform azimuthal angular distribution. The blocking effect in the transverse plane, known for protons, is not found for antiprotons. The influence of the doughnut distribution on the results of the transmission experiments with small acceptance angle detectors is discussed.
Some new aspects of the axial electron channeling process
1993, Nuclear Inst. and Methods in Physics Research, B
Energy loss of axially channeled antiprotons
1992, Nuclear Inst. and Methods in Physics Research, B
A detailed study of energy spectra (channeled fraction, most probable energy loss, shape of the spectra) of low energy antiprotons moving in a thin crystal, under axial channeling conditions is performed using a Monte Carlo computer simulation. The results of calculations for antiprotons are compared with those for protons. It was observed that the channeled fraction of the antiproton beam is considerably smaller than that for protons due to strong dechanneling. This fraction as a function of incident angle shows a maximum at angles near ψ = 0.5ψ_L. Whereas for protons, well aligned with a crystal axis, the energy loss is onsiderably reduced as compared to the random beam, for antiprotons the energy loss is nearly the same as for those in a random direction. The spectra for antiprotons are wider than those for protons and have a high-loss tail. In general the directional effects in energy spectra are less pronounced for antiprotons than for protons.
Computer study on energy loss and multiple scattering of channeled protons and antiprotons
1992, Nuclear Inst. and Methods in Physics Research, B
The energy loss distributions and dechanneling of MeV protons and antiprotons have been studied by computer simulation based on the binary collision model. It is found that a small fraction of antiprotons is channeled anomalously through a crystal. The average energy loss for antiprotons incident along a channel direction is larger (≈ 10%) than that for random incidence. It is also shown that the FWHM of the energy loss distribution for antiprotons strongly depends on the incident angle.
Temperature effect in antiproton channeling
2014, Journal of Surface Investigation

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Section III. Channeling and dechannelingLow-energy antiproton channeling

Abstract

Phys. Rev. Lett.

Phys. Scripta

Section III. Channeling and dechanneling
Low-energy antiproton channeling