Affiliations 

  • 1 Sunway University, Centre for Biomedical Physics, Jalan Universiti, 47500, Subang Jaya, Malaysia; Department of Physics, University of Surrey, Guildford, GU2 7XH, United Kingdom. Electronic address: dbradley@sunway.edu.my
  • 2 Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur, 50603, Malaysia
  • 3 Sunway University, Centre for Biomedical Physics, Jalan Universiti, 47500, Subang Jaya, Malaysia
  • 4 Dept. of Physics, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia
  • 5 Synchrotron Light Research Institute of Thailand and Suranaree University of Technology, 111 University Ave, Muang, Nakhon Ratchasima, 30000, Thailand
Appl Radiat Isot, 2019 May;147:105-112.
PMID: 30852298 DOI: 10.1016/j.apradiso.2019.02.016

Abstract

We explore the utility of controlled low-doses (0.2-100 Gy) of photon irradiation as initiators of structural alteration in carbon-rich materials. To-date our work on carbon has focused on β-, x- and γ-irradiations and the monitoring of radiotherapeutic doses (from a few Gy up to some tens of Gy) on the basis of the thermoluminescence (TL) signal, also via Raman and X-ray photo-spectroscopy (XPS), providing analysis of the dose dependence of single-walled carbon nanotubes (SWCNT). The work has been extended herein to investigate possibilities for analysis of structural alterations in graphite-rich mixtures, use being made of two grades of graphite-rich pencil lead, 8H and 2B, both being in the form produced for mechanical pencils (propelling or clutch pencils). 2B has the greater graphite content (approaching 98 wt %), 8H being a mixture of C, O, Al and Si (with respective weight percentages 39.2, 38.2, 9.8 and 12.8). Working on media pre-annealed at 400 °C, both have subsequently been irradiated to penetrating photon-mediated doses. Raman spectroscopy analysis has been carried out using a 532 nm laser Raman spectrometer, while for samples irradiated to doses from 1 to 40 Gy, XPS spectra were acquired using Al Kα sources (hv ∼1400 eV); carbon KLL Auger peaks were acquired using 50 eV Pass Energy. At these relatively low doses, alterations in order-disorder are clearly observed, defect generation and internal annealing competing as dominating effects across the dose range.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.