Sensors and Actuators A 270 (2018) 72–78 Contents lists available at ScienceDirect Sensors and Actuators A: Physical j ourna l ho me page: www.elsevier.com/locate/sna Radioluminescence of Ge-doped silica optical fibre and Al 2 O 3 :C dosimeters A.K.M. Mizanur Rahman a,c,∗ , Mahfuza Begum b,c , Mahbuba Begum a , H.T. Zubair c , H.A. Abdul-Rashid c , Z. Yusoff c , D.A. Bradley d,e a Health Physics Division, Atomic Energy Centre, Bangladesh Atomic Energy Commission, 4 Kazi Nazrul Islam Avenue, Shahbag, Dhaka 1000, Bangladesh b Health Physics & Radioactive Waste Management Unit, Institute of Nuclear Science and Technology, Atomic Energy Research Establishment, Bangladesh Atomic Energy Commission, Ganakbari, Savar, Dhaka, Bangladesh c Fibre Optics Research Centre, Faculty of Engineering, Multimedia University, Jalan Multimedia, 63100 Cyberjaya, Malaysia d Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom e Sunway University, Institute for Health Care Development, 46150, PJ, Malaysia a r t i c l e i n f o Article history: Received 25 September 2017 Received in revised form 8 December 2017 Accepted 15 December 2017 Available online 19 December 2017 Keywords: Radioluminescence Ge-doped optical fibre NanoDots Al2O3C Afterglow a b s t r a c t Using an electron accelerator producing a 6 MV X-ray photon beam several experimentally observed excitation phenomena that are associated with radioluminescence (RL) have been investigated, the sig- nal originating from a Ge-doped silica optical fibre and commercial nanoDot Al 2 O 3 :C dosimeters. Using PMMA optical communication fibres the RL signals have been guided from the beam-delivery room out to the readout instrumentation that has been located beyond the concrete maze providing effective radi- ation shield. Ge-doped silica fibre memory effects and afterglow (phosphorescence) were compared with that of the commercial Al 2 O 3 :C dosimeter. Immediately following RL, observation was made of the decay curves of the afterglow signal of Al 2 O 3 :C. Conversely, there was little practically observable afterglow for the Ge-doped fibre used for the majority of present investigations (the dopant concentration of this being 3.6 wt %). Among three different concentration of Ge-doped fibres that were subsequently investi- gated in a follow-up study, the intensity of afterglow was found to be greatest for the more highly doped concentration (7.0 wt % Ge), with progressive reduction of the effect for the Ge 4.7 wt % and Ge 3.6 wt % fibres. These observations can be compared against the much more marked RL memory effect observed using the Al 2 O 3 :C chips. Current results point to the Ge-doped silica optical fibre being a highly promising candidate for real-time RL dosimetry and sensing. © 2017 Elsevier B.V. All rights reserved. 1. Introduction Radioluminescence (RL), a phenomenon occurring during the interaction of ionizing radiation with optically transparent mat- ter, has been studied over the past three decades, pointing to RL being a potentially strong candidate for real-time radiation dosime- try. Investigations of RL applied to real-time medical dosimetry are embryonic but of growing interest, increasingly being used as an instance in real-time dose assessment in radiotherapy [1]. RL fibre dosimetry is of particular interest herein, now recognized as an ∗ Corresponding author at: Health Physics Division, Atomic Energy Centre, Bangladesh Atomic Energy Commission, 4 Kazi Nazrul Islam Avenue, Shahbag, Dhaka 1000, Bangladesh. E-mail address: mizanbaec14@gmail.com (A.K.M.M. Rahman). attractive technique [2] and one that can be further strengthened by seeking strong suppression of the noise component towards approaching a noise-free signal. This includes the RL signal needing to be manifestly free of spurious spectral super positions, allow- ing realization of a simple and practical dosimeter by avoiding the need for subtraction or correction algorithms [3]. Instantaneous radiation dose verification can be achieved through conditioning of the RL signal, forming a reliable source of real-time informa- tion. In order to be useful for such purposes, materials need to be sensitive and to have RL signal characteristics that are consistent, distinguishable and linearly responsive with the incident radiation. This is the focus of the present paper. Fibre-coupled luminescence dosimetry represents the state- of-the-art, based on RL/OSL (Optically Stimulated Luminescence) techniques, as currently being applied in the field of medical dosimetry. Here, a small-volume luminescence generating mate- https://doi.org/10.1016/j.sna.2017.12.032 0924-4247/© 2017 Elsevier B.V. All rights reserved.