Passage of fast charged particles through bent crystals and nanotubes

Carbon nanotubes and fullerites in high-energy and X-ray physics

“…As pointed out above, the channeling of high-energy particles in curved nanotube ropes is of special interest due to the possibilities of beam deflection at comparatively large angles. The comparison between the channeling of 1 GeV electrons and positrons along (10, 10) nanotube rope and along [110] axial direction in diamond is carried out in [77] using the simulation method similar to the described above. The continuum potential of diamond at room temperature is shown in Fig.…”

“…At relatively small depths a noticeable part of the beam follows the bend axial channels both in nanotube rope and diamond. However, in nanotubes the beam deflects due to true channeling, while in diamond the deflection is caused rather by multiple scattering of positrons on bent atomic strings [57,77]. When the penetration depth into diamond (deflection angle) increases a considerable part of positrons leaves the axial channels.…”

Channeling and Radiation in Periodically Bent Crystals

“…The examples of such materials are nanotubes and fullerites, for which the channeling effects has been also investigated, see, e.g.,[20, 56,77,88,108,112,[297][298][299]. The examples of such materials are nanotubes and fullerites, for which the channeling effects has been also investigated, see, e.g.,[20, 56,77,88,108,112,[297][298][299].…”

<title>Experimental study of the influence of the motion type of 1 GeV electrons in crystal on features of their radiation spectrum</title>

“…4, at which the electron velocity was changed weakly. Then the Fourier component W(q) of electron acceleration in (6) for the motion on a given trajectory can be represented as W(q) = Iqtn (8) where /\6 = At%1 = -'I,n-1 is the particle velocity change at the n-th part of the trajectory and t is the time when the n-th part of the trajectory begins. Besides, time intervals At are chosen in such a way, that the longitudinal parts of trajectories passed by a particle in a crystal are small compared with the radiation coherence length l. These requirements can always be fulfilled if the number of trajectory partitions in a crystal in the transversal plane is big enough.…”

“…The latter is acquired at every partition ofthe trajectory due to the fluctuations of the lattice potential, connected in its tum with the thermal spread of the crystal atoms locations. So, the continuous potential of a crystal is taken in the form U(3) = U5)+ 5U (8) U-c C'3) is the potential averaged over the thermal oscillations of lattice atoms and 8U is the fluctuation of the potential due to the specific choice of u in a crystal. At the end of each part of a trajectory the value of an electron velocity acquired due to scattering at the potential 8U fluctuations was picked out at random.…”