Luminescence characteristics of C 5+ ions and 60 Co irradiated Li 2 BaP 2 O 7 :Dy 3+ phosphor J.A. Wani a , N.S. Dhoble b , S.P. Lochab c , S.J. Dhoble a,⇑ a Department of Physics, R.T.M. Nagpur University, Nagpur 440033, India b Department of Chemistry, Sevadal Mahila Mahavidhyalaya, Nagpur 440009, India c Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067, India article info Article history: Received 1 November 2014 Received in revised form 10 January 2015 Accepted 25 January 2015 Keywords: Luminescence Dy 3+ ion C 5+ irradiation 60 Co irradiation abstract In this work a study on some thermoluminescence characteristics of Li 2 BaP 2 O 7 :Dy phosphor is presented. The phosphor was synthesized by solid state diffusion method and characterized for its phase purity by X-ray diffraction (XRD). FT-IR spectrum was also carried out to confirm the presence of phosphate family and vibrations corresponding to P–O–P group. Spectroscopic investigation was approached through pho- toluminescence (PL) and thermoluminescence (TL). PL emission spectrum of Dy 3+ ions corresponding to 4 F 9/2 ? 6 H 13/2 (483 nm) and 4 F 9/2 ? 6 H 15/2 (574 nm) transitions is revealed under 351 nm excitation wavelength. This characteristic emission confirms the presence of Dy 3+ ions in the Li 2 BaP 2 O 7 host matrix. To induce TL properties in Li 2 BaP 2 O 7 :Dy phosphor was irradiated with C 5+ ion beams and gamma rays ( 60 Co). A nearly simple glow curve was observed for Li 2 BaP 2 O 7 :Dy under two different excitation sources. TL response is almost linear over a wide range. Average absorbed dose ð  DÞ and mean linear energy trans- fer ð LETÞ of C 5+ ion beams in Li 2 BaP 2 O 7 :Dy have also been calculated. Values of parameters like E and S known as trap depth and frequency factor respectively were obtained by using TLanal computer program. Also SRIM based calculations were performed to study the effect of C 5+ ion beams on the samples of Li 2 BaP 2 O 7 :Dy. SRIM calculations show that Ba 2+ vacancies are highest in number. Till date no such luminescence information on Li 2 BaP 2 O 7 :Dy phosphor is available. Ó 2015 Elsevier B.V. All rights reserved. 1. Introduction Thermoluminescence (TL) is a phenomenon of emission of light by an insulator or a semiconductor previously irradiated by ioniz- ing radiations, which comes into play when the solid is thermally triggered. The position, shape, and intensities of the glow peaks are related to the properties of the trapping states responsible for the TL [1–4]. Thermoluminescent materials exhibit differences in dose response between sparsely ionizing radiation (high energy photons like X-ray and c-ray) and densely ionizing radiation like heavy charged particles (HCP). This is due to different spatial dose distributions. Ion beam effects on the materials depend on the ion energy, fluence and ion species. When an energetic ion sinks in the material it loses its kinetic energy in two modes, (i) nuclear and (ii) electronic stopping. The nuclear stopping is dominant at low ener- gies and the energy lost in this process is called nuclear energy loss. The other mode of energy loss is by exciting or ionizing the atom by inelastic collisions and the energy spent in this process is called electronic energy loss. Electronic stopping is dominant at high energies, where the displacement of atoms due to elastic collisions is insignificant [5]. Heavy ion beams have been used for diagnostic and therapeutic purposes for a long time now [6–8]. The application of radiotherapy (RT) is based on the funda- mental principle of achieving precise dose localization in the target lesion while causing minimal damage to surrounding normal tis- sues. Energy deposition of carbon ion beams increases with penetration depth up to the sharp maximum at the end of their range, known as the Bragg peak [9,10]. The diverse applications of highly energetic radiations in var- ious fields demand that there be other tools for measuring doses/ fluences of such penetrating radiations [11–14]. But, doses need to be determined with high precision and accuracy, particularly, while dealing with human beings. Thermoluminescence phosphors seem to be a good choice for this purpose. However, more analysis is required to verify their dosimetric properties and the defects generated by such heavy ionizing radiation. This will help to devel- op better correlation between many thermally stimulated process- es and the defects generated by these radiations in various phosphors, more realistically, for their possible applications in http://dx.doi.org/10.1016/j.nimb.2015.01.054 0168-583X/Ó 2015 Elsevier B.V. All rights reserved. ⇑ Corresponding author. E-mail address: sjdhoble@rediffmail.com (S.J. Dhoble). Nuclear Instruments and Methods in Physics Research B 349 (2015) 56–63 Contents lists available at ScienceDirect Nuclear Instruments and Methods in Physics Research B journal homepage: www.elsevier.com/locate/nimb