一种高热稳定性的热释光材料MgSO4:Dy,Mn

MgSO     

掺入Dy和Mn的MgSO4磷光体的热释光发光光谱

用光学多道分析器和微机控制线性升温法研究了MgSO4:Dy和MgSO4:Dy,Mn热释光材料的发光光谱,测定不同温度和波长的发光光谱,得到了热释光三维光谱图。观察到MgSO4掺入稀土元素Dy的两个发光谱带为480nm和580nm,每个光谱带有多个发光峰。与掺入Dy的CaSO4的三维发光谱相比较,掺入稀土元素Dy的热释光材料的发光谱带的波长主要取决于掺入Dy^3 的能级间的跃迁。MgSO4同时掺入Dy和Mn后,480nm发光谱带受到很大的抑制,所有发光峰的发光效应显著减小;波长为580nm谱带的多个发光峰中,温度低于300℃的发光峰的发光效率显著减小,在380℃附近的发光峰的发光强度最大。这说明掺入Mn杂质后,不同深度的陷阱的相对分布发生了变化。     

磷光体MgSO4：Tm,P的热释光特性

通过掺杂得到的 Mg SO4∶ Tm,P粉末样品 ,经 60 Co和13 7Csγ辐照后 ,测定了 10 -4～ 2× 10 4Gy范围内的热释光的发光曲线和三维光谱 ,确定了 TL峰的峰参数和陷阱参数值 ,主剂量峰位于 2 89.3℃左右 ,辐射剂量响应为超线性 ,从其发光谱上可看到其发光波长主要位于 36 5、4 6 0、6 6 0 mm。通过与其他材料的比较 ,观测到其灵敏度高 ,剂量响应范围宽 ,稳定性好 ,可作为实用的 TL材料在剂量学中获得应用     

MgSO4：Dy,P和MgSO4：Dy,P,Cu的热释光剂量学特性

MgSO4:Dy中掺入适量的P,热释发光光曲线中两个高温峰显著增强,主剂量峰的峰温接近283．6℃,另一个发光峰的峰温在352．7℃,其热释光效率超过LiF:Mg,Ti的两倍,MgSO4:Dy,P的单个发光峰峰面积对^60Coγ辐射剂量（0．1Gy-20kGy)的实验响应曲线用复合作用响应函数拟合,得到的非线性特征参数表明,两个发光峰的γ辐射量响应均为超线性,在MgSO4:Dy,P中再掺入微量Cu,首先抑制峰温在352．7℃的发光峰,随着Cu浓度的增加,283．6℃的主剂量峰会随之降低,此的γ辐射剂量响应的超线性随之减小,MgSO4:Dy,P,Cu(0.1mol%,0.5mol%,0.01mol%)磷光体对γ辐射的剂理响应（0．1Gy-20kGy)为亚线性,最引人注目的是MgSO4:Dy,P,Cu(0.1mol%,0.5mol%,0.004%mol)磷光体,它具有与MgSO4:Dy,P(0.1mol%,0.5mol%)相近的热释光灵敏度,并具有最宽的剂量响应线性范围,这种新热释光材料可用于高剂量辐射测量。本文进一步阐明和验证了《复合作用模型》,并揭示了热释光材料中杂质和缺隐结构与剂量学特性的相关性,结合热释光三维发光光谱的分析对热释光机制提出一些见解。     

掺Dy,Tm和Mn的MgSO4磷光体的热释光发光谱研究

用高温固相法研制了MgSO₄:Dy,MgSO₄:Tm和MgSO₄:Mn热释光材料,并通过将MgSO₄:Dy和MgSO₄:Mn混合,以及MgSO₄:Tm和MgSO₄:Mn混合烧结得到了双掺杂样品MgSO₄:Dy,Mn,MgSO₄:Tm,Mn。分别测量了这两种样品在不同热处理温度下的三维发光谱。实验结果表明热处理温度为700℃时的样品,在测量加热过程中观察到Dy和Mn离子分别发光,但超过800℃后,Mn发光强度逐渐变弱,而Tm、Dy的高温发光峰逐渐变强,其它温度的发光峰受到抑制。这表明热释光材料中形成的缺陷复合体结构与热处理温度相关,随着热处理温度的升高,愈来愈多的Mn离子与稀土离子结合紧密,因此在热释光发光谱中清楚地观察到Mn离子对稀土离子的能量转移和对Tm、Dy低于400℃发光峰进行抑制的发光过程。     

MgSO4:Tm,Mn,P磷光体的研究

通过三掺杂得到MgSO4：Tm,Mn,P，其热释光的两个主要发光峰温分别约为253℃和383℃，发光波长位于365nm、460nm和660nm。比较MgSO4:Tm、MgSO4:Tm,Mn、MgSO4:Tm,P、MgSO4：Tm,Mn,P的发光曲线，讨论了杂质Tm、Mn、P分别产生的作用。采用一般级动力学方程拟合发光曲线，确定出各发光峰的激活能与频率因子。用^60Co γ射线在0.1-20kGy的辐照范围内，测定了它们的热释光剂量响应曲线。用复合作用剂量响应函数拟合实验数据，得到两个发光峰的一次作用因子R分别为0.397(253℃）和0.127(383℃）。     

一种适用于年代测定的热释光仪

介绍了RGD3B型热释光剂量仪的基本性能，提出了用于年代测定工作时需注意的问题及预防措施。     

一种提高热释光探测器低能光子响应的新方法

ICRU 39号报告提出的四个剂量当量新量值及光子能量响应转换系数,使得一些有效原子序数较低的热释光探测器的低能光子响应变得明显地欠响应。针对这一问题,本文探索了一条加入少量高原子序数添加剂作为“光电子炮弹库”的新途径,既能不起掺杂剂的作用而对原有的优良性能无任何影响,又能有效地抬高低能光子响应并在较大的范围内任意调节低能光子响应的抬高幅度,从而可优选出基本满足Hp(10)和H(10)要求的两种配方。     

一种简便的热释光剂量仪联机接口

介绍了一种在热释光剂量仪上进行数据采集并实时显示,同时具有数据平滑、拟合、数据格式转换、打印等处理功能的微机接口系统,系统由微机和设有计数器的A/D转换电路的接口板,以及系统软件等组成,该系统大大提高了剂量仪在热释光的测量功能,扩大了应用范围,并已用于热释光剂量学和热释光材料的研究。     

热释光材料LiF：Mg,Ti,LiF：Mg,Cu,P和MgSO4的正电子湮没特性

测量了经＾６０Ｃｏγ辐照的热释光材料ＬｉＦ：Ｍｇ，Ｔｉ，ＬｉＦ：Ｍｇ，Ｃｕ，Ｐ和ＭｇＳＯ４的正电子湮没寿命谱，所有寿命谱都分成三个成分，两种不同掺杂的ＬｉＦ样品，其τ２成分寿命参数十分接近，表明正离子空位对寿命谱影响较小，并且观察到，在剂量范围为０．０５－１ｋＧｙ内，τ２成分寿命参数随剂量按相反趋势发生较小的变化，等时退火实验表明，ＭｇＳＯ４样品的τ２和τ３成分与硫酸基有关，其大小可参取决于Ｍｇ＾     

MgSO_4:Dy,P和MgSO_4:Dy,P,Cu的热释光剂量学特性

MgSO4 :Dy中掺入适量的P ,热释光发光曲线中两个高温峰显著增强 ,主剂量峰的峰温接近2 83.6℃ ,另一个发光峰的峰温在 35 2 .7℃ ,其热释光效率超过LiF:Mg ,Ti的两倍。MgSO4 :Dy ,P的单个发光峰峰面积对60 Coγ辐射剂量 (0 .1Gy— 2 0kGy)的实验响应曲线用复合作用响应函数拟合 ,得到的非线性特征参数表明 ,两个发光峰的γ辐射剂量响应均为超线性。在MgSO4 :Dy ,P中再掺入微量Cu ,首先抑制峰温在 35 2 .7℃的发光峰 ,随着Cu浓度的增加 ,2 83.6℃的主剂量峰会随之降低 ,此峰的γ辐射剂量响应的超线性随之减小。MgSO4 :Dy ,P ,Cu (0 .1mol% ,0 .5mol% ,0 .0 1mol% )磷光体对γ辐射的剂量响应 (0 .1Gy— 2 0kGy)为亚线性。最引人注目的是MgSO4 :Dy ,P ,Cu(0 .1mol% ,0 .5mol% ,0 .0 0 4mol% )磷光体 ,它具有与MgSO4 :Dy ,P(0 .1mol% ,0 .5mol% )相近的热释光灵敏度 ,并具有最宽的剂量响应线性范围。这种新热释光材料可用于高剂量辐射测量。本文进一步阐明和验证了《复合作用模型》 ,并揭示了热释光材料中杂质和缺陷结构与剂量学特性的相关性。结合热释光三维发光光谱的分析对热释光机制提出一些见解     

掺入Dy和Mn的MgSO_4磷光体的热释光发光光谱

用光学多道分析器和微机控制线性升温法研究了MgSO4 :Dy和MgSO4 :Dy ,Mn热释光材料的发光光谱。测定不同温度和波长的发光光谱 ,得到了热释光三维光谱图。观察到MgSO4 掺入稀土元素Dy的两个发光谱带为 4 80nm和 580nm ,每个光谱带有多个发光峰。与掺入Dy的Ca SO4 的三维发光谱相比较 ,掺入稀土元素Dy的热释光材料的发光谱带的波长主要取决于掺入Dy3+的能级间的跃迁。MgSO4 同时掺入Dy和Mn后 ,4 80nm发光谱带受到很大的抑制 ,所有发光峰的发光效率显著减小 ;波长为 580nm谱带的多个发光峰中 ,温度低于 30 0℃的发光峰的发光效率显著减小 ,在 380℃附近的发光峰的发光强度最大。这说明掺入Mn杂质后 ,不同深度的陷阱的相对分布发生了变化。     

掺Dy的MgB4O7磷光体的研制及其热释光特性

以碳酸镁和硼酸为原料在高温条件下合成了基质材料MgB4O7并制备了MgB4O7∶Dy磷光体.用RGD-3热释光剂量仪和三维热释光谱仪分别测量了这种磷光体的二维发光曲线和三维发光谱,实验观察到:1)MgB4O7∶Dy磷光体热释光发光峰峰温为220 ℃和380 ℃;2)Dy3 离子的发光波长为480 nm、575 nm和660 nm;3)磷光体220 ℃和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.对比MgB4O7∶Dy和MgSO4∶Dy两种热释光材料的三维发光谱,验证了掺入Dy3 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Dy3 离子的能级跃迁的结果.     

高庙子膨润土在电子辐照和高温老化后热稳定性研究

为研究膨润土的长期稳定性,以高庙子天然钙基膨润土及其改性钠基膨润土为研究对象,利用热重一差示扫描量热（TG-DSC）方法对不同累积剂量的电子辐照和不同温度、不同热作用时间下的老化样品进行了分析。结果表明：高温作用引起的膨润土吸热峰峰值温度和起始温度的变化比电子辐照的大;钠基土比钙基土有更好的耐电子辐照和高温老化能力。在电子辐照／高温老化条件下,改性高庙子钠基膨润土的结构热稳定性比其钙基膨润土好。     

Determination of self attenuation coefficient and relative TL efficiency of CaSO4:Dy, LiF:Mg,Cu,P and LiF:Mg,Ti TLDs - An alternate approach

Self attenuation of TL and relative TL efficiency of polytetra fluoro ethylene (PTFE) embedded CaSO₄:Dy disc, LiF:Mg,Ti (MTS) disc and LiF:Mg,Cu,P (MCP-N) chip were determined in the present study for photons of energy 10-34 keV. The relative TL efficiency was determined using an alternative approach in which ratio of experimental response and corrected theoretical response was used instead of measuring the absolute TL emission in photon counting mode. For CaSO₄:Dy disc, it was found that with increasing the proportion of CaSO₄:Dy phosphor in the disc, the light attenuation coefficient increases. The light attenuation coefficient of MTS disc and MCP-N chip was found to be 23.4 and 45.5 cm⁻¹, respectively. The relative TL efficiency in the photon energy range of 10-34 keV for MTS discs and MCP-N chips, evaluated in the present study matches well with the reported values in the literature.     

LiMgPO4:Tb,B OSL phosphor - CW and LM OSL studies

In the adjoining paper, the authors have proposed LiMgPO₄:Tb,B (LMP) OSL phosphor as a potential alternative to α-Al₂O₃:C for dosimetry applications. This calls for developing an understanding on TL and OSL aspects of this highly sensitive LMP phosphor. CW and LM OSL processes were therefore studied experimentally and kinetic analysis was carried out using theoretical models. Continuous wave (CW) OSL curve for LMP phosphor was found not to follow single decaying exponential implying that the CWOSL curve does not follow first order kinetics. Under pre-readout annealing at 125, 200 and 300 °C for 10 s, the nature of decay profile was unaffected and same holds true for optically bleached CWOSL curves. From linearly modulated (LM) OSL studies, it was found that the shape/geometrical factor μ_g was ∼0.72 ± 0.03 for wide range of doses (up to 12 Gy studied) and peak position “t_m” was also independent of dose. The μ_g was found to be unaffected with pre-readout annealing at 125, 200 and 300 °C for 10 s and optical bleaching, however it was found that peak position “t_m” shifted towards higher side in time with increase of optical bleaching. Dose dependence tests were also carried out for LMOSL curves and it was found that peak position “t_m” was independent of dose, which is typical characteristic of curves following first order kinetics. Hence LM-OSL curve might be mixture of more than one component.Further from CW and LM OSL studies, it was also found that the individual contribution from first, second and third TL peak toward OSL is ∼33%, ∼45% and ∼22%, respectively. Traps beyond 350 °C were found not to contribute towards OSL when stimulated using blue LEDs. In the present paper, the CW and LM OSL processes for LMP phosphor were studied experimentally and their kinetic analysis was carried out.     

Thermoluminescence properties of nanocrystalline K2Ca2(SO4)3:Eu irradiated with gamma rays and proton beam

Thermoluminescence properties of nanocrystalline K₂Ca₂(SO₄)₃:Eu prepared by ball milling technique have been studied and the nanophosphor’s suitability as an effective gamma radiation and proton beam dosimeter material has been examined. It is found that the nanophosphor is suitable for dosimetry over a very wide range of doses ∼1 Gy to 1 kGy for gamma radiation. And for proton beam the same nanophosphor shows a more or less linear response for the dose range 0.1-100 Gy. A comparative study of this nanophosphor with its corresponding microcrystalline form (prepared by solid-state diffusion method) as well as the nanocrystalline form prepared by (the more conventional) co-precipitation technique has shown that the nanophosphor prepared by the ball milling technique is in almost all respects better than the other two forms reported earlier.