Emission and x-ray characteristics of vertically and random aligned carbon nanotubes

Abstract

Carbon nanotubes (CNTs) have gained great popularity due to their unique physicochemical properties. In this work, an important advantage of CNTs is the cold emission of electrons, which occurs when only an electric field is supplied to the nanotube. The use of CNTs as electron emitters in X-ray sources provides several advantages, which allows the use of X-ray sources in the treatment of a number of oncological diseases. In this work, we compared the emission and X-ray characteristics of random and vertically aligned carbon nanotubes (VACNTs). Random CNTs were synthesized by the method of atmospheric pressure alcohol catalytic chemical vapor deposition (AP ACCVD), and VACNTs were synthesized using plasma chemical vapor deposition (PECVD). It was found that random CNTs provided an X-ray dose rate of 1.4 Gy/h at an emission current density of 4 mA/cm2 and an electric field of 2.05 V/μm, while VACNTs provided 0.63 Gy/h at an emission current density of 0.2 mA/cm2 and an electric field of 4.8 V/μm. The characteristics of both random CNTs and VACNTs obtained at room temperature are already acceptable for single fractions in contact therapy of some oncological diseases (for example, skin cancer).