Browsing by Author "Abdul-Rashid, H.A."

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LiZnBO3 phosphor for dosimetry applications
(2024-05-15) Azharul Islam, Shah; Kamruzzaman, Md; Raghib Rahat, Md; Hossain, Shahadat; Abdul-Rashid, H.A.; Khandaker, Mayeen Uddin; Bradley, D.A.; Al-Mamun, Md; Mizanur Rahman, A.K.M.
This study explores the dosimetric potentials of pristine lithium zinc borate, LiZnBO3, (LZB) phosphor for medical application. The pristine LZB was synthesized by the solid-state reaction (SSR) technique. The structural properties of the synthesized composites were investigated by X-ray diffraction (XRD) and Fourier Transform Infrared (FT-IR) measurements. The FT-IR data shows that the functional groups are responsible for the peak intensity of LZB. The magnetic hysteresis (M-H) loop was characterized using Vibrating Sample Magnetometry (VSM) to distinguish its magnetic characteristics and alterations. From the M-H loop, it behaves as a superparamagnetic material. A clinical Linear Accelerator (LINAC) was used to irradiate the samples with both electron (6 MeV) and X-ray photon beam (6 MV), with a dose range of 0.5 Gy–8 Gy for both beams. The experiment was designed to study low to medium-dose TL response for LZB. The irradiated samples were readout for thermoluminescence (TL) signal using a Harshaw-3500 TL reader with a fixed heating rate of 10 °C/s. The TL kinetic parameters of the composites were studied by analysing the glow curves using the peak-shape method. The geometric factor (μg) is found to be within the range of 0.42–0.52, which indicates the suitability of applying Chen's general-order formula to calculate kinetic parameters. The activation energy (E) is found in the range of 1.13–3.14 eV for 4 deconvoluted peaks of 6 MeV electron beam irradiation and 1.82–2.16 eV for 3 deconvoluted peaks of 6 MV X-ray photon beam irradiation. The frequency factor (s) also increases while activation energy increases for both electron and X-ray photon beams. All the obtained results confirm the suitability of LZB phosphor to develop a viable radiation dosimeter.
Synthesis, Characterization and Thermoluminescence Properties of LiCaPO4 Phosphor for Ionizing Radiation Dosimetry
(Elsevier, 2023-12-15) Rahat, Md Raghib; Mimi, Homaira Afia; Islam, Shah Azharul; Kamruzzaman, Md.; Ferdous, Jannatul; Begum, Mahfuza; Hasnat, Md Abul; Abdul-Rashid, H.A.; Muslima, Umme; Khandaker, Mayeen Uddin; Bradley, D.A.; Al-Mamun, Md.; Rahman, A.K.M. Mizanur
Many minerals and compounds show thermoluminescence (TL) properties but only a few of them can meet the requirements of an ideal dosimeter. Several phosphate materials have been studied for low-dose dosimetryin recent times. Among the various phosphates, ABPO4-type material shows interesting TL properties. In this study, an ABPO4-type (A = Lithium, B=Calcium) phosphor is synthesized using a modified solid-state diffusion method. Temperature is maintained below 800 °C in every step of phosphor preparation to obtain the pure phase of Lithium calcium phosphate (LiCaPO4). The purpose of this work is to synthesize LiCaPO4 using a simple method, examine its structural and luminescence properties in order to gain a deeper understanding of its TL characteristics. The general TL properties, such as TL glow curve, dose linearity, sensitivity, and fading, are investigated. Additionally, this study aims to determine various kinetic parameters through Glow Curve Deconvolution (GCD) method using the Origin Lab software together with the Chen model. XRD analysis confirmed the phase purity of the phosphor with a rhombohedral structure. Lattice parameters, unit cell volume, grain size, dislocated density, and microstrain were also calculated from XRD data. Raman analysis and Fourier Transform Infrared analysis were used to collect information about molecular bonds, vibrations, identity, and structure of the phosphor. To investigate TL properties and associated kinetic parameters, the phosphor was irradiated with 6.0 MV (photon energy) and 6.0 MeV (electron energy) from a linear accelerator for doses ranging from 0.5 Gy to 6.0 Gy. For both photon and electron energy, TL glow curves have two identical peaks near 200 °C and 240 °C.The TL glow curves for 0.5 Gy–6 Gy are deconvoluted, then fitted with the appropriate model and then calculated the kinetic parameters. Kinetic parameters such as geometric factor (μg), order of kinetics, activation energy (E), and frequency factor (s) are obtained from Chen's peak shape method. The dose against the TL intensity curve shows that the response is almost linear in the investigated dose range. For photon and electron energy, the phosphor is found to be the most sensitive at 2.0 Gy and 4.0 Gy, respectively. The phosphor shows a low fading and after 28 days of exposure, it shows a signal loss of better than 3%. The studied TL properties suggest the suitability of LiCaPO4 in radiation dosimetry and associated fields.