Theory of Planar Channeling of Relativistic Protons in Bent Crystals

Abstract

Dechanneling of relativistic protons in planar channels of bent crystals is examined on the basis of the Fokker-Planck equation. The dependence of the dechanneling half-length x 1 p in a curved channel of (110) Si on the particle energy E and the bending radius R is found. It is shown that in the bent crystal the dechanneling lengths are considerably reduced and the proportionality between the x1/2 value and the particle energy E is violated. The optimum conditions for deflection of a proton beam a t the definite angle by a bent crystal are considered. PaccMaTpHsaeTcR neKaHanHpoBaHHe penmmHcTcK~x IIPOTOHOB B nnocKocTHbIx IcaHajIax nonyronmtiabr neKaHannposaHm x l / e B M~O~H Y T O M (110) Si OT 3~e p r m sacmq E EI

Optimal radius of crystal curvature for planar channeling of high-energy negatively charged particles in a bent crystal

“…Thus, one should expect the presence of optimal radius of curvature in the case of planar channeling of negatively charged particles in a bent crystal. It should be noted that the existence of the optimal radius of crystal curvature for positively charged particles deflection had been shown for the first time in [9] and the analytical expression for the optimal crystal curvature for positively charged particles was suggested in [10,11].…”

Channeling and Radiation in Periodically Bent Crystals

“…Theoretical analysis of various phenomena related to the channeling in bent crystals (classical treatment), including the dechanneling effect, can be found in [94,95,97,189,274]. The review of theoretical models and computational methods can be found in [68,271].…”

Effect of dechanneling on the photon emission by ultra-relativistic positrons channeling in a periodically bent crystal

“…This change, ∆n 0 , is the smallest for the straight channels and its magnitude increases with C. Such a behaviour is explained as follows. The probability for the projectile to undergo the largeangle scattering from the crystal electrons or/and nuclei is proportional to the volume densities n el (ρ) and n n (ρ) (see (46)(47)(48)(49)(50)). The large-angle scattering, i.e.…”

“…The first approach is based on the diffusion theory applied to describe the multiple scattering (e.g. [11,17,48,49]. The second approach is in direct computer simulation of the scattering process [50,12].…”