一种天然正长石的释光特性

应用RGB-3B型热释光仪和BG2003释光谱仪对一种正长石矿物的热释光和选频释光发光曲线进行测定,获得正长石的释光特性。研究表明：天然正长石的三个热释光峰峰温为148,197,310 ℃,辐照一定剂量后,出现197 ℃和263 ℃两个稳定的热释光峰。正长石的峰位温度随着增温速率的减小,向左移动。选频热释光290, 300, 310, 340, 400, 480 nm存在释光响应,选频绿光释光280, 290, 300, 310, 320, 400, 460, 480 nm存在释光响应,400 nm频道的光子计数随剂量的变化具有一定的线性关系,具有辐射剂量计的特性,具备释光测年的应用潜力。     

α-Al2O3: Mn单晶的三维热释发光谱研究

测量了α-Al2O3: Mn单晶中子辐照前后的三维热释发光谱.观察到α-Al2O3: Mn:Mn单晶γ射线照射后测量的三维热释发光谱中，峰温在350℃波长为680nm处有一宽发光峰，这可能与Mn2+离子有关；波长为695nm峰温在170℃和350℃的线状光谱，叠加在680nm宽发光峰上，是Cr3+离子的发光谱线,其中可能有Mn4+离子的贡献.与纯α-Al2O3单晶的热释发光谱相比，掺入Mn杂质后，γ射线照射的三维热释发光谱中完全地抑制了波长为416nm的α-Al2O3的F心发光峰.经1017cm-2中子注量辐照和退火后，γ射线照射后测量的三维热释发光谱中，在150℃出现了波长为416和695nm的发光峰，以及在250℃波长为680和695nm的发光峰，其中695nm新发光峰的强度略超过了中子辐照前α-Al2O3:Mn在350℃波长为695nm的发光峰，说明中子辐照产生了大量浅陷阱能级和F心.然而，经1018cm-2中子注量辐照和退火后，γ射线照射后测量的三维热释发光谱中，出现了峰温150℃，190℃和250℃波长为520nm的Mn2+离子发光峰，以及300℃波长为680和695nm的Cr3+（或Mn4+）的发光峰，表明增高中子注量的辐照，产生了温度为190℃，250℃和300℃深陷阱能级和F心，并使Mn2+离子发光峰明显加强. 关键词： α-Al2O3:Mn 三维发光谱 缺陷结构 发光机理     

Spectral study on feldspar thermoluminescence process

Feldspar thermoluminescence fading phenomena were investigated here by using newly-constructed thermoluminescence spectrometer on the basis of charge-coupled detector, and thereafter the discussion and explanation on feldspar TL fading mechanism were presented. The experimental results show that the fading rate of feldspar TL depends on both wavelength and stimulated temperature, and normally the feldspar TL in every region of wavelength and temperature shows different traits, namely the low temperature TL (170°–190°) fading at the rate of logarithmic function and furthermore the TL of different wavelengths fading at approximately the same rate on the condition of 160° preheating. While the medium and high temperature TLs (290°–400°) do not show much thermal fading, their fading rate at room temperature invariably correlates well with their wavelength, namely the longer TL wavelength, the slower TL fading rate. The thermal instability of traps and the quantum-mechanical tunneling effects can explain the above fading phenomena respectively. It is recognized that feldspar TL fading depends on its wavelength, and furthermore new aspects of the solid thermoluminescence process can be displayed by the combination of three-dimensional TL spectral analysis and thermal fading or anomalous fading of TL for feldspar. Supported by the National Natural Science Foundation of China (Grant No. 40534019) and the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. GIGCX3-07-10)     

Thermoluminescence of Chromium Doped Cd2Nb2O7 Crystals

The exposure of the Cd₂Nb₂O₇:Cr crystal to monochromatic light with wavelength shorter than 600 nm at 12 K decreases the Cr^3? photoluminescence emission and allows us to observe thermoluminescence within 60–200 K during subsequent heating of the crystal at a rate of 0.077 K/s. The glow curve of thermoluminescence revealed a rather complex structure with two pronounced intensive glow peaks at 91 and 180 K and four rather weak peaks at 99, 117, 132, and 155K. An analysis of the glow peaks by “an initial rise” gave evidence of many various charge carrier traps with activation energies from 150 to 470 meV. Since a comparison of the thermoluminescence and photoluminescence emission spectra showed that these spectra are identical, it was concluded that the thermoluminescence glow peaks are associated with thermal release of charge carriers from shallow traps followed by Cr^4?→Cr^3?(²E) and/or Cr^2?→Cr^3?(²E) charge capture and ²E→⁴A₂ radiative decay of Cr^3?(²E) ions.     

Dy或Tb掺杂的MgB4O7磷光体的热释光特性

用高温固相反应法研制了MgB₄O₇:Dy和MgB₄O₇:Tb两种热释光材料.用自制的三维热释光谱仪测量了两种磷光体的三维发光谱,从MgB₄O₇:Dy磷光体的三维发光谱观察到:1.热释光发光峰峰温为220,380℃;2.Dy³⁺离子的发光波长为480,575,660nm;3.220,380℃发光峰的相对强度随高温固相反应温度的升高而变化,但发光峰温和波长基本保持不变.由MgB₄O₇:Tb磷光体的三维发光谱可看到在230,340,420℃附近有三个发光峰,发光谱线波长分别为489,543,589,620nm.不同的高温烧结温度不仅对发光峰的发光强度有很大影响,而且还对Tb³⁺发光谱形产生影响,当温度高于850℃时Tb³⁺离子发光谱线开始变成了发光谱带.此外,对比MgB₄O₇:Dy和MgB₄O₇:Tb两种热释光材料的二、三维发光谱,得出了掺入三价稀土离子的热释光材料的发光峰峰温主要由基质材料决定,发光波长则取决于稀土离子的4f电子能级间的跃迁.     

Lu2SiO5∶Ce荧光粉的热释光特性研究

采用溶胶-凝胶(Sol-Gel)技术,分别在空气中和石墨提供的弱还原气氛下制备出Lu2SiO5∶Ce0.006荧光粉。通过分析样品的结构,光致激发、发射谱和热释光谱等特性,发现弱还原气氛下制备的样品不仅光致发光强度比空气中的强,而且热释光曲线中598K处的高温热释光峰也得到了抑制。进一步考察空气中制备的Lu2SiO5∶Ce0.006,Kx(x=0.01～0.08)荧光粉,结果表明就光致发光和热释光特性而言,K+共掺杂具有与还原气氛类似的作用。综合以上两方面分析结果,可认为598K处热释光峰是由与Ce4+相关的缺陷引起的,并对K+共掺杂LSO∶Ce发光增强的原因给出了合理解释。     

Radio- and thermoluminescence of single-doped and codoped lithium-sodium sulfate

Radioluminescence at room temperature and thermoluminescence (TL) measurements of single-doped and codoped LiNaSO₄ above room temperature are reported here. The codoped samples were studied to investigate the possibility of enhancing the TL sensitivity of LiNaSO₄:Eu. This objective was not satisfied and the codopants (Ce, Sm, Ho and Er) decrease the TL sensitivity and slightly shift the dosimetric peak to lower temperatures. Samples doped with Mg, K, Bi and Tl were used with the hope that they may alter the trapping centers stability and introduce new peaks in the temperature range 430–500 K to observe any TL discontinuity or wavelength shift in their spectra as observed in CL measurements. This objective was fulfilled with Tl and Bi, where there is a discontinuity and/or wavelength shift at about 460 K. Such intensity and/or wavelength variations are ascribed to microstructural phase changes within the LiNaSO₄ crystals that may result from twin boundaries behaving like Na₂SO₄.     

Investigation of cordierite lattice defects by thermoluminescence experiments

Summary The thermoluminescence of α- and μ-cordierite samples has been recordedvs. temperature and wavelength. Arguments ascribing the observed emission to the easy ion exchanges characterizing cordierite lattices are advanced.     

α-Al2O3单晶的热释光和光释光特性

研究了纯α-Al₂O₃单晶的热释光发光曲线和三维发光谱，以及光释光衰变曲线，对它们的发光机理和剂量学特性进行了分析和讨论.实验观察到α-Al₂O₃单晶β射线照射后立即测量的热释光发光曲线，有峰温为76℃和207℃两个发光峰.经γ射线照射数小时后测量的三维发光谱，只有峰温207℃波长为416 nm发光峰，它与α-Al₂O₃:C晶体的发光波长基本相同，是受热激发到导带的电子与F< 关键词： 2O₃')" href="#">α-Al₂O₃ 三维发光谱 TL/OSL剂量响应     

Charge Transfer between Neutron-Induced and Activator Centers in LuAG:Pr Single Crystal

Optics and Spectroscopy - The spectra of absorption and gamma luminescence and integral thermoluminescence curves (300–605 K) of nominally pure LuAG crystals and praseodymium-doped LuAG:Pr...     

α-Al_2O_3透明陶瓷的发光及热释光特性

采用传统无压烧结工艺,以MgO为烧结助剂,制备出了透明性良好的α-Al2O3透明多晶陶瓷,测定了其吸收光谱、荧光光谱、激发光谱,并做了热释光测试.结果表明,吸收光谱存在192nm和225—250nm吸收峰,分别对应于F色心和F+色心.在荧光光谱的410nm处发现有明显的发射峰.结合对其激发光谱的研究,证明了对应于F和F+色心.热释光谱中存在368,456,614K三个热释光峰,其中456K的峰值是受热激发的电子与F+色心复合产生的.     

Anomalies in a Lithium Niobate Stoichiometric Crystal in the Temperature Range 100–400 K

Optics and Spectroscopy - We show that the differences in the anomalous temperature behaviors of thermoluminescence and line intensities in the Raman spectra of congruent and stoichiometric lithium...     

The radiothermoluminescence of (ZnS:CdS:Ag:Ni:Co) phosphors irradiated with beta-rays

The radiothermoluminescence characteristics have been studied for a number of (ZnS:CdS::Ag:Ni:Co) phosphors, with various cobalt impurity contents, after exposure to⁹⁰Sr beta-rays at room temperature. Thermoluminescent spectra show a peak wavelength of 7000 Å, which remains unchanged with increase in cobalt concentration. Thermoluminescence curves exhibit a single well-defined peak appearing at temperatures far above room temperature. This peak shifts to lower temperatures with increasing cobalt content. The relation between thermoluminescence response and dose is linear over the dose range of 1 to 500 rads. Thermoluminescence measurements made after storing the irradiated phosphor for 48 hours in dark have revealed an information loss of 4% over this storage period. The radiothermoluminescence characteristics, storage capacity and storage stability of these sulphide phosphors compete reasonably with those of lithium fluoride over the dose range of 1 rad to 500 rads.     

Luminescence studies of rare earth doped yttrium gadolinium mixed oxide phosphor

This paper reports the photoluminescence and thermoluminescence properties of gamma ray induced rare earth doped yttrium gadolinium mixed oxide phosphor. The europium (Eu³⁺) was used as rare earth dopant. The phosphor was prepared by chemical co-precipitation method according to the formula (Y_2−x−yGd_x) O₃: Eu_y³⁺ (x=0.5; y=0.05). The photoluminescence emission spectrum of the prepared phosphor shows intense peaks in the red region at 615 nm for ⁵D₀→⁷F₂ transitions and the photoluminescence excitation spectra show a broad band located around 220–270 nm for the emission wavelength fixed at 615 nm. The thermoluminescence studies were carried out after irradiating the phosphor by gamma rays in the dose range from 100 Gy to 1 KGy. In the thermoluminescence glow curves, one single peak was observed at about 300 °C of which the intensity increases linearly in the studied dose range of gamma rays. The glow peak was deconvoluted by GlowFit program and the kinetic parameters associated with the deconvoluted peaks were calculated. The kinetic parameters were also calculated by various glow curve shape and heating rate methods.     

Luminescence in LiNaSO4:Eu phosphor

Abstract

LiNaSO₄: Eu is a recently discovered thermoluminescence dosimetry (TLD) phosphor which is more sensitive than the widely used CaSO₄:Dy. In this paper results are reported on TL glow curves, TL emission spectra and PL photoluminescence. These measurements help to understand the role of impurity and the mechanism of thermoluminescence in this phosphor.     

Destruction mechanism of color centers and recombination luminescence in NaCl-Cd crystal phosphors

The authors have studied the origin of integral thermoluminescence peaks and the destruction mechanism of color centers during thermal relaxation of X-irradiated NaCl-Cd phosphors. The luminescence spectra have also been studied, and previous similar results are discussed.     

Effect of Fe,Co, Ni and Cd CO‒activation on luminescence emission and decay of CaS:Ce phosphors

Cathodoluminescence (CL), photoluminescence (PL), thermoluminescence (TL) spectra, and decay after laser beam excitation of cerium-activated CaS phosphors doped with Fe, Co, Ni or Cd have been investigated. These studies shed some light on the nature of luminescence centres and the association of various groups of traps with the dopants. Effect of concentiation variation of these four elements on emission and decay characteristics of CaS:Ce phosphor has been discussed. In contrast with the earlier publication [W. Lehmann and F. M. Ryan, J. Electrochem. Soc. 119, 275 (1972)] we have found that Ni is an effective killer, Cd ineffective and Co has no clearly observable effect. Fe has also been found to be an effective killer for CaS:Ce phosphors. Ni and Fe appear to be more effective quenchers for shorter wavelength emission band characteristic of Ce in CaS.     

Luminescent properties of LiCl-Cu single crystals

The absorption, photoluminescence, x-ray luminescence, and thermoluminescence spectra, and the photoluminescence excitation spectra of LiCl-Cu single crystals with different activator concentration were investigated at temperatures of 79–450°K. The absorption spectrum at room temperature has two bands with maxima at 237 and 259 nm. The absorption coefficient of the 237 nm band is proportional to the copper concentration in the crystal (C_Cu ≤ 7·10^?4 mole %). The photoluminescence and x-ray luminescence spectrum at room temperature consists of one emission band at 324 nm, which conforms with the Mollwo-Ivey rule in the homologous series RbCl → KCl → NaCl → LiCl. The copper ions create trapping levels for electrons and holes at different depths in the forbidden band of the LiCl crystal. The correlation between the thermoluminescence peaks and the recombination-luminescence excitation bands (infrared stimulation) is investigated.     

Investigation of the disintegration mechanism of color centers,and recombination luminescence of the (NaCl-Ag,Ca)-crystal phosphor. II

The investigation of relaxation processes in alkali-halide phosphor crystals excited by X-rays is continued.The mechanism of disintegration of color centers, the occurrence of thermoluminescence peaks, as well as the spectra of thermally stimulated and photo-stimulated luminescence, are investigated for a (NaCl-Ag, Ca)-crystal phosphor.     

Optical bleaching studies of quartz

The bleaching properties of a hydrothermal, Arkansas quartz are studied in detail. The thermoluminescence (TL) and phototransferred TL (PTTL) signals are examined as a function of wavelength, illumination time and temperature at which the sample is illuminated. We have also briefly studied the effects of pre-irradiation annealing on the sample. The results of these experiments are described and their relevance to the models for TL is discussed.