Identification of the types of carbon nanotubes using donut effects

We investigate the angular distributions of protons of initial energy 10 MeV after channeling through a (6, 4), (8, 6), (11, 9) and (15, 10) single-wall carbon nanotube, each of length 1μm. The interaction between the proton and nanotube atoms is described by Doyle-Turner interaction potential. The angular distributions of channeled protons are generated using a Monte Carlo computer simulation code, based on the numerical solutions of the proton equations of motion in the transverse position plane. As the proton incident angle increases and approaches the critical angle for channeling, a ring-like structure is developed in the angular distribution known as the donut effect. Its appearance in the proton angular distribution is highly dependent on the size and type of nanotube. Thus, we propose that the donut structure produced by a given carbon nanotube could act as a sort of “fingerprint”, allowing one to identify the nanotube type.