Neutron Scattering in Nanotubes

Abstract

Neutron scattering has got numerous applications in various fields of research like material research, crystallography etc. Thermal neutron scattering in randomly un-aligned multi walled carbon nanotubes is based on its anisotropic frequency distribution function. This frequency distribution function is obtained using a dynamical model which includes the presence of both the surface modes and intertube coupling. Experimentally measured values of specific heat for randomly un-aligned multi walled carbon nanotubes has been studied to detect the phonon frequency distribution function. Elastic scattering is used for analyzing structures. Inelastic scattering is applied for the study of atomic vibrations. The dynamical model has been used to find the scattering values. Both scattering values are calculated and compared. It was concluded that the difference in their values is large. This difference would affect the transport processes in randomly un-aligned multi walled carbon nanotubes

Introduction

I. INTRODUCTION

Neutron scattering is a technique for examining the materials. The free neutrons which are emitted by atomic nuclei in nuclear reactions have high energy. So, these neutrons cannot be used to study the structure of the crystals. They are passed through a moderator of less atomic mass, high neutron scattering cross-section and thus their energy gets decreased.

Neutrons act together with atomic nuclei and magnetic fields from unpaired electrons. Energy transfer occurs in scattering experiments. Neutron scattering and absorption cross sections vary generally from isotope to isotope. The scattering consists of elastic and an inelastic component. The fraction of elastic scattering is described by the Debye-Waller factor or the Mossbauer-Lamb factor.

II. METHOD

A. Thermal Neutron Scattering Cross-Section

The dynamical model is applied to get frequency distribution function. [1,2]. Experimental values of specific heat for the case of un-aligned multi walled carbon nanotubes is given by Mizel etal [3]. These values have been studied to get frequency distribution function. The differential scattering cross-section [4, 5] of thermal neutrons, for the case of a solid, is expressed as follows:

Conclusion

[1] Tewari SP, Silotia P and Bera K (1997) Role of Collective and localized modes on the temperature dependent thermal conductivity in polycrystalline C60 Fullerite Compacts. Mod. Phys. Lett. B 11:1031. https://doi.org/10.1142/S0217984997001249. [2] Silotia P, Dabas S, Saxena A and Tewari SP (2011) Phonon frequency distribution function and temperature variation of Rayleigh Mossbauer scattering fraction from aligned multiwalled carbon nanotube. Journal of Nanophotonics 5: 053508. doi:10.1117/1.3590198. [3] Mizel A, Benedict LX, Cohen ML, Louie SG, Zettl A, Budraa NK, Beyermann WP (1999) Analysis of the low temperature specific heat of multiwalled carbon nanotubes and carbon nanotube ropes. Phys. Rev. B 60: 3264. doi: https://doi.org/10.1103/PhysRevB.60.3264. [4] Tewari S.P., Silotia P, Bera K and Saxena A (2003) Energy dependent total thermal neutron scattering cross-section and transport of a neutron pulse in Fullerite at 300K. Proceedings of SPIE, Nanotubes and Nanowires 5219: 117. [5] Dabas S (2022) Thermal Neutron scattering of Un-Aligned Multi-walled Carbon Nanotubes. International Journal for Research in Applied Science & Engineering Technology 10 (Issue IV): 1346. https://doi.org/10.22214/ijraset.2022.41520.

Copyright

Copyright © 2022 Dr. Seema Dabas. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.