P M Bhujbal  S J Dhoble 《Luminescence》2013,28(6):879-881

The thermoluminescence (TL) characterizations of γ‐irradiated KCl:Dy phosphor for radiation dosimetry are reported. All phosphors were synthesized via a wet chemical route. Minimum fading of TL intensity is recorded in the prepared material. TL in samples containing different concentrations of Dy impurity was studied at different γ‐irradiation doses. Peak TL intensities varied sublinearly with γ‐ray dose in all samples, but were linear between 0.08 to 0.75 kGy for the KCl:Dy (0.1 mol%) sample. This material may be useful for dosimetry within this range of γ‐ray dose. TL peak height was found to be dependant on the concentration (0.05–0.5 mol%) of added Dy in the host. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

    

Piyush Jha  B.P. Chandra 《Luminescence》2017,32(2):171-176

The present paper reports the impulsive excitation of mechanoluminescence (ML) in Sr_0.97Al₂O₄:Eu_0.01,Dy_0.02 nanophosphors prepared using a combustion technique. The phosphors are characterized using X‐ray powder diffraction (XRD), high‐resolution transmission electron microscopy (HRTEM) and photoluminescence (PL). The XRD results show that the samples exhibit a monoclinic α‐phase in the crystal structure. The space group of SrAl₂O₄:Eu,Dy nanophosphors is monoclinic P2₁. The PL and ML spectra of SrAl₂O₄:Eu,Dy nanophosphors are excited using light with a wavelength of 365 nm and emission is found at 516 nm. The prepared nanophosphors exhibits an intense ML that can be seen in daylight with the naked eye. When a sample powder is deformed impulsively by the impact of a moving piston, the ML intensity initially increases linearly with time, attains a peak value, I_m, at time t_m, and then decreases with time. The peak ML intensity, I_m, and total ML intensity, I_T, increase linearly with applied pressure and impact velocity. The ML intensity decreases with successive impacts of load onto the phosphors, and the diminished ML intensity can be approximately recovered by UV irradiation. The activation energy using thermoluminescence is found to be 0.57 eV for SrAl₂O₄:Eu,Dy nanophosphors. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

    

V. Nayar  P. S. Chowdhary  P. M. Bhujbal  S. J. Dhoble 《Luminescence》2011,26(5):324-330

The temperature and mass dependence of lyoluminescence intensity of γ‐irradiated colored potassium chloride powder have been studied using a photomultiplier tube connected to an x–y recorder. The peak lyoluminescence intensity increases with increasing amount of solute added up to 50 mg and then tends to saturate. The lyoluminescence (LL) glow curves with mass of KCl microcrystals show that initially the LL intensity increases with time and then decreases exponentially with time. The decay time consists of two components for all the masses. The dependence of decay time, especially the longer component on mass, has been investigated. The temperature dependence of LL intensity shows that initially the peak LL intensity increases with temperature up to 60°C, and then decreases with further increase in temperature. The decay time tends to decrease with increasing temperature. An explanation for the experimental results has been attempted. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

    

A. K. Sahu  Monali R. Kadukar  P. S. Chowdhary  V. Nayar  S. J. Dhoble 《Luminescence》2014,29(8):1082-1094

Li₃PO₄ phosphors prepared by solid‐state diffusion technique and lyoluminescence (LL) as well as mechanoluminescence (ML) studies are reported. Dy‐ and Tb‐activated phosphors show dosimetric characteristics using LL and ML techniques. The energy levels and hence trapping and detrapping of charge carriers in the material can be studied using ML. Li₃PO₄ phosphor can be used in the dosimetric applications for ionizing radiation. By using the LL technique, the LL characteristics of Li₃PO₄ may be useful for high radiation doses. We also report a more detailed theoretical understanding of the mechanism of LL and ML. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

    

Javaid A. Wani  N.S. Dhoble  S.J. Dhoble 《Luminescence》2013,28(5):751-754

Thermoluminescence characteristics of Dy³⁺‐activated Mg₅(BO₃)₃F low Z_eff phosphor are described. The Mg₅(BO₃)₃F phosphor doped with Dy³⁺ as activator was prepared by the modified solid‐state reaction. Formation of the compound was confirmed by use of X‐ray powder diffraction. The X‐ray powder diffraction pattern of the as‐prepared compound shows a good match with the available JCPDS data. The γ‐irradiated Mg₅(BO₃)₃F:Dy³⁺ phosphor shows a simple glow curve peaking at about 148°C indicating that only one type of trap is being activated within a particular temperature range. The kinetic parameters, including activation energy and frequency factor were determined using Chen's method. The activation energy and frequency factors were 0.75 eV and 4.508 × 10⁹/s respectively. The Z_eff of Mg₅(BO₃)₃F:Dy³⁺ phosphor was 9.84. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

    

Geetanjali Tiwari  Nameeta Brahme  R. Sharma  D. P. Bisen  Sanjay Kumar Sao  Manisha Singh 《Luminescence》2016,31(3):793-801

Ce³⁺‐doped calcium aluminosilicate phosphor was prepared by a combustion‐assisted method at an initiating temperature of 600°C. Structural characterization was carried out using X‐ray diffraction (XRD) and scanning electron microscopy (SEM). The absorption spectra of Ca₂Al₂SiO₇:Ce³⁺ showed an absorption edge at 230 nm. The optical characterization of Ca₂Al₂SiO₇:Ce³⁺ phosphor was investigated in a fracto‐mechanoluminescence (FML) and thermoluminescence (TL) study. The peak of ML intensity increased as the height of impact of the moving piston increased. The TL intensity of Ca₂Al₂SiO₇:Ce³⁺ was recorded for different exposure times of UV and γ‐irradiation and it was observed that TL intensity was maximum for a UV irradiation time of 30 min and for a γ‐dose of 1180 Gy. The TL intensity had three peaks for UV irradiation at temperatures 82°C, 125°C and 203°C. Also the TL intensity had a single peak at 152°C for γ‐irradiation. The TL and ML emission spectra of Ca₂Al₂SiO₇:Ce³⁺ phosphor showed maximum emission at 400 nm. The possible mechanisms involved in the TL and ML processes of the Ca₂Al₂SiO₇:Ce³⁺ phosphor are also explained. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

    

Arati Duragkar  Aarti Muley  N.R. Pawar  Vibha Chopra  N.S. Dhoble  O.P. Chimankar  S.J. Dhoble 《Luminescence》2019,34(7):656-665

Thermoluminescence (TL) materials exhibit a wide range of applications in different areas such as personal dosimetry, environmental dosimetry, medical research etc. Doping of different rare earth impurities in different hosts is responsible for changing the properties of materials useful for various applications in different fields. These materials can be irradiated by different types of beams such as γ‐rays, X‐rays, electrons, neutrons etc. Various radiation regimes, as well as their dose–response range, play an important role in thermoluminescence dosimetry. Several TL materials, such as glass, microcrystalline, nanostructured inorganic materials and recently developed materials, are reviewed and described in this article.  相似文献   

    

Monali R.Kadukar  S. J. Dhoble  A. K. Sahu  V. Nayar  S. Sailaja  B. Sudhakar Reddy 《Luminescence》2017,32(2):159-170

This article reports on the luminescence properties of rare earth (Dy³⁺ and Tm³⁺)ions doped SrGa₂Si₂O₈ phosphor were studied. SrGa₂Si₂O₈phosphors weresynthesizedby employing solid state reaction method.From the measured X‐ray diffraction (XRD) pattern of the samplemonoclinic phase structure has been observed. Thermoluminescenceand Mechanoluminescence properties of the γ‐ray irradiated samples have been studied. Photoluminescence spectra of Dy³⁺ activated SrGa₂Si₂O₈phosphor has been measured with an excitation wavelength at 348 nm,and it shows two emission bands at 483 and 574 nm due to ⁴F_9/2 → ⁶H_15/2 and ⁴F_9/2 → ⁶H_13/2 transitions respectively. Whereas the photoluminescence spectra of Tm³⁺ activated SrGa₂Si₂O₈ phosphor has been measured with an excitation wavelength at 359 nm and it exhibits two emission bands at 454 and 472 nm due to ¹D₂ → ³F₄ and¹G₄ → ³H₆ transitions respectively. In thermoluminescence study, γ‐irradiatedthermoluminescence glow curve of SrGa₂Si₂O₈:Dy³⁺ phosphor shows two well defined peaks at 293 °C (peak1)and 170 °C (peak2) whereas thermoluminescence glow curve of SrGa₂Si₂O₈:Tm³⁺ phosphor shows peaks at 292 °C (peak1) and 184 °C (peak2) indicating that two sets of traps are being activated within the particular temperature range and the trapping parameters associated with the prominent glow peaks of SrGa₂Si₂O₈:Dy³⁺ and SrGa₂Si₂O₈:Tm³⁺ are calculated using Chen's peak shape and initial rise method.From the Mechanoluminescence study, only one glow peak has been observed. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

    

Geetanjali Tiwari  Nameeta Brahme  Ravi Sharma  D. P. Bisen  Sanjay Kumar Sao  Ishwar Prasad Sahu 《Luminescence》2016,31(8):1479-1487

A series of Ce³⁺ ion single‐doped Ca₂Al₂SiO₇ phosphors was synthesized by a combustion‐assisted method at an initiating temperature of 600 °C. The samples were annealed at 1100 °C for 3 h and their X‐ray diffraction patterns confirmed a tetragonal structure. The phase structure, particle size, surface morphology and elemental analysis were analyzed using X‐ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM) and energy dispersive X‐ray (EDX) spectroscopy techniques. Thermoluminescence (TL) intensity increased with increase in ultraviolet (UV) light exposure time up to 15 min. With further increase in the UV irradiation time the TL intensity decreases. The increase in TL intensity indicates that trap concentration increased with UV exposure time. A broad peak at 121 °C suggested the existence of a trapping level. The peak of mechanoluminescence (ML) intensity versus time curve increased linearly with increasing impact velocity of the moving piston. Mechanoluminescence intensity increased with increase in UV irradiation time up to 15 min. Under UV‐irradiation excitation, the TL and ML emission spectra of Ca₂Al₂SiO₇:Ce³⁺ phosphor showed the characteristic emission of Ce³⁺ peaking at 400 nm (UV–violet) and originating from the Ce³⁺ transitions of 5d‐4f (²F_5/2 and ²F_7/2). The photoluminescence (PL) emission spectra for Ca₂Al₂SiO₇:Ce³⁺ were similar to the ML/TL emission spectra. The mechanism of ML excitation and the suitability of the Ca₂Al₂SiO₇:Ce³⁺phosphor for radiation dosimetry are discussed. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

    

Upadhyay AK  Dhoble SJ  Kher RS 《Luminescence》2011,26(6):471-476

BaSO(4) activated with various concentrations of Eu were prepared by solid-state reaction technique. Thermoluminescence (TL) and mechanoluminescence (ML) of γ-ray-irradiated BaSO(4):Eu(2)O(3) phosphors were recorded. In the TL glow curve of the phosphor a single peak at 170°C was observed. The TL of the phosphors were also recorded after deforming the phosphors by dropping a piston of mass 0.4 kg onto them with different impact velocities. TL intensity (after deformation) decreased with increasing the impact velocity. In the ML intensity vs time curve two peaks were observed. ML intensity increased with increasing impact velocity of the piston and the time corresponding to peak ML intensity shifted to a shorter time value. ML intensity decreased drastically when it was recorded after annealing the sample at 170°C. The BaSO(4) phosphors activated with 0.1 mol% of Eu(2)O(3) showed optimum TL and ML. The photoluminescence emission spectrum of the sample showed that Eu enters as Eu(2+) ion in host lattice.  相似文献   

    

Ishwar Prasad Sahu  D. P. Bisen  Nameeta Brahme  Manju Ganjir 《Luminescence》2015,30(8):1318-1325

Sr₂MgSi₂O₇:Eu²⁺ and Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ long afterglow phosphors were synthesized under a weak reducing atmosphere by the traditional high temperature solid state reaction method. The synthesized phosphors were characterized by powder X‐ray diffraction (XRD), energy dispersive X‐ray spectroscopy (EDX), and photo‐, thermo‐ and mechanoluminescence spectroscopic techniques. The phase structure of the sintered phosphor was an akermanite type structure, which belongs to tetragonal crystallography. The thermoluminescence properties of these phosphors were investigated and compared. Under ultraviolet light excitation, the emission spectra of both prepared phosphors were composed of a broad emission band peaking at 470 nm. When the Sr₂MgSi₂O₇:Eu²⁺ phosphor was co‐doped with Dy³⁺, the photoluminescence (PL), afterglow and mechanoluminescence (ML) intensity were strongly enhanced. The decay graph indicated that both the sintered phosphors contained fast decay and slow decay processes. The ML intensities of Sr₂MgSi₂O₇:Eu²⁺ and Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ phosphors were increased proportionally with increasing impact velocity, a finding that suggests that these phosphors could be used as sensors to detect the stress of an object. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

    

Shalinta Tigga  Nameeta Brahme  D. P. Bisen 《Luminescence》2016,31(7):1306-1312

The present paper describes the synthesis of cerium‐doped barium magnesium aluminate phosphor by combustion method. The crystal structure of synthesized phosphor belongs to the P6₃/mmc space group and is related to the β‐alumina structure. The photoluminescence emission spectra exhibited a broad peak centered at 440 nm showing the Ce³⁺ emission. The thermoluminescence properties of phosphors under ultraviolet irradiation were investigated. The activation energy was calculated by Chen's empirical method. Fracto‐mechanoluminescence properties were also investigated. The phosphor showed mechanoluminescence (ML) properties without irradiation and the ML intensity increased linearly with the impact height of the moving piston. Therefore this compound may have a use as a damage sensor. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

    

A. K. Sahu  Bhushan P Kore  P. S. Chowdhary  V. Nayar  S. J. Dhoble 《Luminescence》2014,29(1):58-64

Li₃PO₄ phosphor was prepared using a modified solid‐state diffusion technique. In this work, photoluminescence, lyoluminescence and mechanoluminescence studies were carried out in a Li₃PO₄ microcrystalline powder doped with different rare earths. In photoluminescence studies, characteristic emission of Ce and Eu was observed. The lyoluminescence glow curves of Li₃PO₄ microcrystals show that lyoluminescence intensity initially increases with time and then decreases exponentially. The decay time consists of two components for all masses. The dependence of decay time, especially the longer component, on mass has been investigated. Experiments on γ‐irradiated crystals have proved that the light emission originates from the recombination of released F‐centres with trapped holes (V₂‐centres) at the sulfuric acid–solid interface. Incorporation of bivalent alkali in solid lithium phosphate leads to an enhancement of lyoluminescence. A possible explanation for the experimental results has been attempted. The phosphor has a mechanoluminescence single glow peak. Mechanoluminescence intensity under various loading conditions was investigated. It is observed that mechanoluminescence intensity increases with increasing impurity concentration and increasing piston impact velocity. The results may be considered as only being of academic interest in solid‐state materials. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

    

Ishwar Prasad Sahu  D. P. Bisen  K. V. R. Murthy  R. K. Tamrakar 《Luminescence》2017,32(7):1263-1276

Ca₂MgSi₂O₇:Ce³⁺, Ca₂MgSi₂O₇:Eu²⁺ and Ca₂MgSi₂O₇:Eu²⁺,Ce³⁺ phosphors were prepared using the solid‐state reaction method. The crystal structures of the sintered phosphors were of melilite type, which has a tetragonal crystallography. The chemical compositions of the sintered phosphors was confirmed by energy dispersive X‐ray spectroscopy. The different thermoluminescence kinetic parameters [activation energy (E), frequency factor (s) and order of the kinetics (b)] of these phosphors were evaluated and compared using the peak shape method. Under ultraviolet excitation, the emission spectra of both Ca₂MgSi₂O₇:Eu²⁺ and Ca₂MgSi₂O₇:Eu²⁺,Ce³⁺ phosphors were composed of a broad emission band peaking at 530 nm. When the Ca₂MgSi₂O₇:Eu²⁺ phosphor is co‐doped with Ce³⁺ ions, photoluminescence, afterglow and mechanoluminescence intensity was strongly enhanced. Ca₂MgSi₂O₇:Eu²⁺ showed some afterglow with a short persist time. On incorporation of Ce³⁺, efficient energy transfer from Ce³⁺ to Eu²⁺ was found and the emission intensity of Eu²⁺ was enhanced. The mechanoluminescence intensities of Ca₂MgSi₂O₇:Ce³⁺, Ca₂MgSi₂O₇:Eu²⁺ and Ca₂MgSi₂O₇:Eu²⁺,Ce³⁺ phosphors increased proportionally increased with the increase in impact velocity, which suggests that these phosphors can be used as sensors to detect stress in an object.  相似文献   

    

Ishwar Prasad Sahu 《Luminescence》2017,32(3):364-374

In the present article we report europium‐doped strontium ortho‐silicates, namely Sr₂SiO₄:xEu³⁺ (x = 1.0, 1.5, 2.0, 2.5 or 3.0 mol%) phosphors, prepared by solid state reaction method. The crystal structures of the sintered phosphors were consistent with orthorhombic crystallography with a Pmna space group. The chemical compositions of the sintered phosphors were confirmed by energy dispersive X‐ray spectroscopy (EDS). Thermoluminescence (TL) kinetic parameters such as activation energy, order of kinetics and frequency factors were calculated by the peak shape method. Orange‐red emission originating from the ⁵D₀–⁷F_J (J = 0, 1, 2, 3) transitions of Eu³⁺ ions could clearly be observed after samples were excited at 395 nm. The combination of these emissions constituted orange‐red light as indicated on the Commission Internationale de l'Eclairage (CIE) chromaticity diagram. Mechanoluminescence (ML) intensity of the prepared phosphor increased linearly with increasing impact velocity of the moving piston that suggests that these phosphors can also be used as sensors to detect the stress of an object. Thus, the present investigation indicates that the piezo‐electricity was responsible for producing ML in the prepared phosphor.  相似文献   

    

Ishwar Prasad Sahu  D. P. Bisen  Nameeta Brahme 《Luminescence》2015,30(5):526-532

Ca₂MgSi₂O₇:Eu²⁺,Dy³⁺ phosphor was prepared by the solid‐state reaction method under a weak reducing atmosphere. The obtained phosphor was characterized using X‐ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), energy dispersive X‐ray spectroscopy (EDX) and Fourier transform infrared (FT‐IR) techniques. The phase structure of the Ca₂MgSi₂O₇:Eu²⁺,Dy³⁺ phosphor was akermanite type, which is a member of the melilite group. The surface morphology of the sintered phosphor was not uniform and phosphors aggregated tightly. EDX and FT‐IR spectra confirm the elements present in the Ca₂MgSi₂O₇:Eu²⁺,Dy³⁺ phosphor. Under UV excitation, a broadband emission spectrum was found. The emission spectra observed in the green region centered at 535 nm, which is due to the 4f–5d transition. The mechanoluminescence (ML) intensity of the prepared phosphor increased linearly with increases in the mechanical load. The ML spectra were similar to the photoluminescence (PL), which indicates that ML is emitted from the same emitting center of Eu²⁺ ions as PL. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

    

Akhilesh Jadhaw  Vivek D. Sonwane  Anubha S. Gour  Piyush Jha 《Luminescence》2017,32(7):1349-1353

We report the thermoluminescence properties of Sr_1.96Al₂SiO₇:Eu_0.04 and Sr_1.92Al₂SiO₇:Eu_0.04Dy_0.04 phosphors. These phosphors were prepared by a high‐temperature solid‐state reaction method. The prepared phosphors were characterized by X‐ray diffraction. A 254 nm source was used for ultraviolet (UV) irradiation and a ⁶⁰Co source was used for γ‐irradiation. The effect of heating rate and UV‐exposure were examined. The thermoluminescence temperature shifts to higher values with increasing heating rate and thermoluminescence intensity increases with increasing UV exposure time. The trapping parameters such as activation energy (E), order of kinetics and frequency factor (s) were calculated by peak shape method. The effect of γ‐ and UV‐irradiation on thermoluminescence studies was also examined.  相似文献   

    

Digambar A. Ovhal  Bandana Samant  N.S. Dhoble  D.M. Mohabey  S.J. Dhoble 《Luminescence》2020,35(3):332-340

The present study describes for the first time thermoluminescence (TL) characterization of turtle shell. A fossil shell was collected from the Dongargaon area in the Chandrapur district of Maharashtra, India. TL was recorded and a comparative study of TL for the above material was performed to understand the special TL characteristics of the shell. The shell was irradiated with ⁶⁰Co γ‐radiation to study its TL properties. The sample displayed two good TL peaks at 135°C and 255°C. A linear dose–response curve for the irradiated sample was produced for the dose range 0.79–28.5 kGy; this sample of turtle shell (fossil) may be useful as a high dose dosimetry phosphor in this range. This geological sample was further characterized using X‐ray diffraction to confirm its phase structure and by scanning electron microscopy , Fourier transform infrared and wavelength dispersive X‐ray fluorescence spectroscopy to determine morphology, vibration, and elemental composition as ppm or percentage of the sample, respectively. Kinetic parameters of the TL glow peak were calculated using three different methods.  相似文献   

    

Sansar Chand  Rohit Mehra  Vibha Chopra 《Luminescence》2023,38(10):1780-1788

This study reports the thermoluminescence (TL) aspects of Ca₁₀K(PO₄)₇:Dy phosphor synthesized using a wet chemical method for the first time. The X-ray diffraction (XRD) results confirm the formation of the desired crystalline phase. Surface morphological studies reveal the formation of polyhedrons and agglomerations having an average diameter of 200 nm, while energy dispersive X-ray spectroscopy (EDS) data show the presence and composition of the elements in appropriate amounts. The effect of Dy doping concentration has been studied on the TL properties with exposure to gamma radiations from the Co-60 source. The best TL response has been observed for 5 mol% Dy doping concentration. The glow curve is simple and consists of a single peak at 130°C. The effect of the heating rate has been studied on the TL glow curve, and the heating rate of 5°C/s shows the best TL response. The various TL properties such as annealing conditions, dose–response, TL linearity, fading, and reusability of the prepared phosphor have been studied to check its suitability as a good TL dosimeter (TLD). TL characterization of the phosphor reports that the TL response is linear from 5- to 2000 Gy. The results show that this phosphor can be a good TLD for the dosimetry of gamma radiations from Co-60.  相似文献   

    

Mohammad Ziyauddin  Shalinta Tigga  Nameeta Brahme  D. P. Bisen 《Luminescence》2016,31(1):76-80

Calcium aluminate phosphors activated by Dy³⁺ have been prepared by a combustion method at a temperature of 600°C. Photoluminescence (PL) and thermoluminescence (TL) properties of gamma‐irradiated Dy‐doped calcium aluminate were investigated. The PL spectrum shows a broad peak around 488 nm and 573 nm, under 347 nm excitation. Thermoluminescence studies were performed for different concentrations of Dy. Optimum intensity of photoluminescence was found for 0.02 mol% concentration of Dy. It was found that initially the peak TL intensity increases with increasing concentration of Dy in the CaAl₂O₄ host, attains a maximum value for 0.05 mol% concentration and decreases with further increase in the doping concentration due to concentration quenching. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献