Observation of strong reduction of multiple scattering for channeled particles in bent crystals

W Scandale,G Auzinger,V Guidi,G Hall,F Iacoangeli,V Puill,A.S Denisov,M Garattini,T James,A.M Taratin,F Murtas,G Cavoto,S Gilardoni,L.P Lapina,Yu.E Sandomirskiy,L.G Malyarenko,A Mazzolari,R Losito,Yu.A Gavrikov,L Bandiera,A Stocchi,F Cerutti,M Romagnoni,V Chaumat,J Borg,L Burmistrov,S Montesano,M Pesaresi,F Galluccio,A Masi,G Arduini,E Bagli,S Dubos,Jihane Maalmi ,A Yanovich ,D Bretón ,Francesca Maria Addesa ,A D Kovalenko ,Stefano Redaelli ,Roberto Rossi ,V V Skorobogatov ,Yu A Chesnokov ,V A Maisheev ,Daniele Mirarchi ,Yu M Ivanov ,G.i Smirnov ,A G Afonin ,A Durum

doi:10.1016/j.physletb.2020.135396

Abstract

Strong reduction of multiple scattering for channeled particles has been observed in an experiment on the deflection of a 180 GeV/c π+-meson beam by bent silicon crystals. The RMS deflections due to multiple scattering for the channeled particles were about six times smaller than for non-channeled ones. It was shown that the approach suggested recently for the description of multiple scattering for channeled particles using the experimental data for random crystal orientations gives fair agreement with the experiment.

Highlights

When high energy charged particles enter a crystal with small angles relative to the crystal planes, θo 1, their transverse motion is governed by a crystal potential, U (x), averaged along the planes [1]
It was shown that the approach suggested recently for the description of multiple scattering for channeled particles using the experimental data for random crystal orientations gives fair agreement with the experiment
This paper presents the measurement results for multiple scattering of a 180 GeV/c π +-meson beam in two bent silicon crystals with length of 23 mm and 4 mm for their optimal orientations for channeling

Summary

Introduction

When high energy charged particles enter a crystal with small angles relative to the crystal planes, θo 1, their transverse motion is governed by a crystal potential, U (x), averaged along the planes [1]. In the case of planar orientations far from the main axes the deflection angle distribution of particles in the direction parallel to the crystal planes is determined only by incoherent scattering. These distributions can be used to study multiple scattering for channeled particles. The density of atomic nuclei and electrons averaged along the trajectories of channeled particles with small oscillation amplitudes is smaller than for the amorphous crystal orientations when only incoherent scattering of incident particles occurs in a crystal. This paper presents the measurement results for multiple scattering of a 180 GeV/c π +-meson beam in two bent silicon crystals with length of 23 mm and 4 mm for their optimal orientations for channeling. The experimental results are compared with simulations using the model described in [4]

Experimental layout and results

Simulations of multiple scattering

Findings

Conclusions