[en] Nanocrystalline aluminium oxide (NAO) was synthesized by combustion technique and characterized by XRD, TEM etc. The results confirm the formation of nanoparticles of ∼ 20 nm. Pellets of NAO were irradiated with energetic swift heavy ions. An IL band with peak at 420 nm along with a sharp emission at ∼ 695 nm is observed. Dy³⁺ doped NAO shows emission in the range 475-500 nm and 525-600 nm. PL emission at ∼ 544 nm besides a weak emission at 780 nm were observed. A single TL glow with peak at ∼ 538 K is observed in Si⁷⁺ irradiated samples. (author)

[en] Thermoluminescence (TL) of as it is and heat treated gaodati single crystals bombarded with 100 MeV Ag⁺⁸ in the dose range l x 10¹¹- 7.5x1x10¹¹ ions/cm² have been studied at room temperature. A single and well resolved glow peak at ∼530K is observed in all the samples. It is observed that the TL intensity is less in ion irradiated samples when compared to gamma irradiated samples. The characterization of as it is and ion irradiated are studied using Raman studies and Infrared spectroscopy. The Raman studies indicate the characteristic mode v₁(SO₄) at 1008 cm^-1 is present in all the samples. It is observed that the intensity of v₁(SO₄) mode increases up to 5x10¹¹ ions/cm² and there after it decreases. In case of heat treated samples, the v₁(SO₄) mode decrease up to 400 deg C and there after it increases. The decrease in intensity of v₁(SO₄) mode with increase of ion fluence is attributed to amorphisation of material. The increase in v₁(SO₄) mode above 400 deg C might be to structural changes from gypsum to bassanite. (author)

[en] Rare earth (RE) ion doped in ZrO_2: thermoluminescence (TL) properties are modified and glow curve shifted towards higher temperature. Fading is less in ZrO_2:RE. RE doped ZrO_2 have been attracted materials scientists due to its unique properties viz good thermal and chemical stabilities, low thermal conductivity, low phonon energy in zirconia matrix and enhancement of luminescence properties. ZrO_2: RE (Er"3"+, Pr"3"+) synthesized by combustion technique. Samples are annealed at 850°C for three hour. The obtained products mainly exhibits monoclinic structure confirmed by XRD and Raman spectroscopy. Average crystallite size is 32 nm. Grains show spherical shape with size 55-65 nm characterized by FESEM

[en] TL glow curves of 2.249 KGy γ-rayed (Al_1-xLa_x)₂O₃ show a single and well resolved glow with peak at ∼495 K. The TL glow peak intensity is found to increase up to 5 mol% of lanthanum and thereafter decreases. This is due to luminescence quenching. It is observed that the glow peak temperature is shifted towards lower temperature region with increase in mol% of La. Further, in 1 mol% La doped samples it is observed that, TL intensity at ∼492 K increases with increase in γ-ray dose up to 6.753 KGy. The results are discussed in detail. (author)

[en] The objective of the present work is to study photoluminescence (PL), Time resolved PL (TRPL) and Electron spin resonance (ESR) of combustion and sol-gel derived 100 MeV swift Ni"7"+ irradiated Y_2O_3:Tb"3"+ nanophosphors with fluence 1 x 10"1"0 - 3 x 10"1"2 ions cm"-"2. The formation of compounds was confirmed by the X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR) and Raman Spectroscopy. XRD patterns confirm cubic phase with decrease in crystallite size after swift heavy ion (SHI) irradiation. TRPL of SHI irradiated sample showed enhanced life time decay. Also, SHI irradiated Tb doped Y_2O_3 showed enhanced green emission intensity, life time and low phonon energy

[en] Full text: Aluminum oxide is the most mature high technology ceramic material. It finds applications in radiation environments viz luminescence screens, radiation shielding etc. Pure and Dy³⁺ doped nanocrystalline aluminum oxide is prepared by combustion process and characterized by XRD and TEM techniques. The crystallite sizes are observed in the range 25-30 nm. The ionoluminescence of pure and Dy³⁺ doped nanocrystalline aluminum oxide is done using 100 MeV Si⁷⁺ ions in the fluence rage 3.5x10¹³ to 2.3x10¹⁵ ions cm^-2. A strong and sharp emission with peak at ∼695 nm is observed along with the weak emissions at 345 and 420 nm in pure nanocrystalline aluminum oxide. The IL emission with peak at 695 nm originates from the Cr³⁺ ions. It is found that the IL intensity of ∼695 nm decreases with increase in ion fluence. The weak emission with peak at ∼345 and 420 nm are attributed to F⁺ and F-centers respectively. The concentration of F-centers is higher in nanocrystalline samples when compared to microcrystalline aluminum oxide. The characteristic emission of Dy³⁺ ion in the range 475-500 nm with a prominent peak at 493 nm and 525-600 nm with peak at 588 nm are observed in nanocrystalline aluminum oxide. It is found that the IL intensity at both 493.36 and 588.40 nm decreases with increase in ion fluence. However, the IL intensity of Dy³⁺ emission is higher in nanocrystalline Al₂O₃ when compared to its microcrystalline counterpart. The results are discussed in detail in comparison with microcrystalline aluminum oxide

[en] This paper reports the thermoluminescence (TL) response of Er"+"3 doped Y_2O_3 nanophosphor irradiated with 100 MeV swift Si"8"+ ions. Pure and Er"3"+ doped Y_2O_3 are synthesized by the sol-gel technique using citric acid as complexing agent. The synthesized samples are characterized by X-ray diffraction (XRD), Fourier transformer infra red (FT-IR) and scanning electron microscopy (SEM) techniques. The average crystallite size of Er"3"+ doped Y_2O_3 found to be ∼ 29 mn with cubic phase. The synthesized samples in pellet forms are irradiated with 100 MeV swift Si"8"+ ions with fluence in the range of 3x10"1"1 - 3x10"3 ions cm"-"2. Three well resolved TL glows with peaks at ∼ 422, 522 and 598 K are observed in both pure as well as in Er"3"+ doped Y_2O_3 samples. The prominent TL glow peak (∼422 K) intensity is found to decrease with increasing ion fluence. Interaction of ionizing radiation with inorganic solids leads to creation of defects such as F, F"+, F_2, F_2"+ etc in sequence. Consequently TL of such materials give rise to various glow peaks depending upon the fluences received. Also, it is well established that production of such defects increase with fluence and reach saturation and then decay in sequence with further increase of fluence

[en] Yttrium oxide is one of the best hosts for rare earth (RE) ions, because of its similarities in the chemical properties and ionic radius of RE ions. Trivalent dysprosium ion (Dy"3"+) has been extensively studied in various hosts due to its unique spectral properties. Ionoluminescence (IL) is a sensitive and versatile tool for study of excitation of higher electronic levels inside the material, local symmetry of the emitting atom and presence of transition metals and RE ions. The objective of the present work is to study 100 MeV swift Si"8"+ ion induced luminescence of Y_2O_3:Dy"3"+ nanophosphors. Pure and Dy"3"+ doped Y_2O_3 are synthesized by the solution combustion technique. Samples synthesized were made in pellet form (diameter 8 mm and thickness 1 mm) and heat treated at 1173 K followed by irradiation with 100 MeV swift Si"8"+ ions. X-ray diffraction patterns confirms the cubic phase (JCPDS No: 88-1040) of Y_O_3. The crystallite size estimated using Scherrer formula is found to be ∼ 33.3 nm

[en] Pure and Mg"2"+ doped ZnO nanoparticles are synthesized by solution combustion method. X-ray diffraction studies of the samples confirm hexagonal phase. Crystallite size is calculated using Scherer formula and found to be ∼30 nm for undoped ZnO and 34–38 nm for Mg"2"+ doped ZnO. A broad PL emission in the range 400–600 nm with peaks at 400, 450, 468, 483, 492, 517, 553 nm are observed in both pure and Mg"2"+ doped nanoparticles. Near band edge emission of ZnO is observed at 400 nm. The broad band emissions are due to surface defects. PL emission intensity is found to increase with Mg"2"+ concentration up to 1.5 mol% and then decreases due to concentration quenching. Samples are irradiated with γ-rays in a dose range 0.05–8 kGy. Gamma irradiation doesn’t affect PL properties. Undoped samples exhibit unstructured low intense TL glow with peak at 720 K. Whereas Mg"2"+ doped samples exhibit well structured TL glow curves with peak at ∼618 K. TL glow peak intensity of Mg"2"+ doped samples increases with Mg"2"+ concentration up to 2 mol%, thereafter decreases. TL curves of Mg"2"+ (2 mol%) doped ZnO exhibit two glows, a high intense peak at 618 K and a weak one with peak at ∼485 K. TL intensity of Mg"2"+ (2 mol%) doped ZnO samples increases with gamma dose up to 1 kGy and then decreases. Kinetic parameters of TL glows are calculated by deconvolution technique. Activation energy and frequency factor are found to be 1.5 eV and 3.38 × 10"1"1 s"−"1 respectively.

[en] Strontium aluminate is one of the most widely used host lattices for obtaining luminescent pigments with high intensity and long decay time. SrAl₂O₄ is synthesized by the solution combustion method. PXRD patterns of 1400 °C annealed SrAl₂O₄ confirm the monoclinic phase with space group P21. The crystallite size of the sample is estimated from Scherrer’ formula and found to be 44 nm. TL glow curve of beta irradiated phosphor shows three prominent peaks at 84°C, 116°C, 242°C and a broad secondary peak at 395°C. TL intensity maxima of these peaks increase with beta dose. TL kinetic parameters are calculated using various heating rate and glow curve deconvolution methods. (author)