Contents lists available at ScienceDirect Applied Radiation and Isotopes journal homepage: www.elsevier.com/locate/apradiso Samarium doped boron nitride nanotubes Wellington Marcos da Silva, Tiago Hilário Ferreira, Carlos Antônio de Morais, Alexandre Soares Leal, Edésia Martins Barros Sousa ⁎ Nuclear Technology Development Center (CDTN) – Avenida Presidente Antônio Carlos, 6627 Pampulha, 31270-901 Belo Horizonte, MG, Brazil HIGHLIGHTS • BNNTs doped in situ with samarium were synthesized by thermal chemical vapor deposition. • Sm-doped BNNTs sample was acti- vated by neutron capture, producing 152 Sm radioisotopes. • The results demonstrate that this ma- terial has great potential as a nano- system in nuclear medicine. GRAPHICAL ABSTRACT ARTICLE INFO Keywords: Boron nitride nanotubes Samarium Doping Synthesis Catalyst ABSTRACT Boron nitride nanotubes doped in situ with samarium (Sm-doped BNNTs) were synthesized at 1150 °C under atmosphere of NH 3 /N 2 gas mixture by thermal chemical vapor deposition (TCVD) using samarium oxide that is a product of the process separation of thorium and uranium tailings. The samarium in the BNNTs sample was activated by neutron capture, in a nuclear reactor, producing 152 Sm radioisotopes. The STEM-EELS spectrum and neutron activation show energies attributed to the samarium confirming the in situ doping process during BNNTs growth. The results demonstrate that this material has great potential as a nanosized β - emission source for medical therapy. 1. Introduction The synthesis of boron nitride nanotubes (BNNTs) was first reported in 1995 by Chopra, based on an arc discharge method, producing a type of one-dimensional (1D) nanostructure (Chopra et al., 1995). Currently, several methods of synthesis have been employed, such as laser abla- tion, autoclaving, ball milling and chemical vapor deposition (CVD). CVD is the most advanced and convenient technique for the synthesis of BNNTs because it requires a simple apparatus (Ahmad et al., 2015). Various types of catalysts may also be used in the synthesis process, including metallic oxide nanoparticles (Ferreira et al., 2011; Huang et al., 2011; Tang et al., 2002a; Koi et al., 2008; Lee et al., 2010; Matveev et al., 2015; özmen et al., 2013; Tang et al., 2002b; Wang et al., 2016). Recently BNNTs have attracted significant interest for scientific and technological applications due to their high resistance to oxidation, high thermal stability, excellent thermal conductibility, high Young's modulus, piezoelectricity, and the ability to suppress thermal neutron radiation (Chen et al., 2004; Cohen et al., 2010; Golberg et al., 2010; Nakhmanson et al., 2003). Doping modifications can effectively tune the BNNTs electronic structure and expand their applications (Chen et al., 2010, 2008, 2007). In this sense they are a highly pro- mising material for applications such as shields/capsules, filler for composites, self-cleaning materials, and in biology and medicine (Ciofani et al., 2013a, 2009; Golberg et al., 2010; Pakdel et al., 2011). Nanometer-sized luminescent materials are very important for potential nanometer-sized light sources, lasers, display devices and medical di- agnosis (Chen et al., 2008, 2007). Wide-bandgap semiconductors doped with rare-earth ions are considered as a new type of luminescent ma- terial, combining special wide-bandgap semiconducting properties with the rare-earth luminescence feature (Liu et al., 2002; Vetter et al., 2004). BNNTs have a stable wide bandgap of 5.5 eV which makes BNNTs an ideal nanonosized luminescent material (Blase et al., 1994; http://dx.doi.org/10.1016/j.apradiso.2017.10.045 Received 18 May 2017; Received in revised form 29 August 2017; Accepted 24 October 2017 ⁎ Corresponding author. E-mail address: sousaem@cdtn.br (E.M. Barros Sousa). Applied Radiation and Isotopes 131 (2018) 30–35 0969-8043/ © 2017 Elsevier Ltd. All rights reserved. MARK