Temporal signal stability of KCl:Eu(2+) storage phosphor dosimeters.
Temporal signal stability of KCl:Eu(2+) storage phosphor dosimeters.
复制标题
KCl:Eu(2) 存储荧光粉剂量计的时间信号稳定性。
DOI：
10.1118/1.4789482
复制
发表时间：
2013
期刊：
影响因子：
3.8
通讯作者：
Li,HHarold
中科院分区：
文献类型：
--
作者：
Xiao,Zhiyan;Hansel,Rachael;Chen,Haijian;Du,Dongsu;Yang,Deshan;Li,HHarold
目的：当前KCl：Eu 2+原型剂量计在辐照和剂量测定读数之间需要12 h的等待时间。尽管在晚上照射剂量计并在第二天阅读在临床时间表中工作良好，但期望将等待时间减少到几个小时。这项工作的目的是确定不稳定的电荷存储中心的起源，并确定这些中心是否响应于光或热激发之前的剂量ready.Methods：丸式KCl：Eu 2+剂量计制造本研究的内部。使用6 MV光子束照射剂量计。X射线辐照后，剂量计接受近红外（NIR）光、紫外（UV）光或热处理的外部激发。随后，使用实验室PSL读出系统在室温下测量了几个小时内的光刺激发光（PSL）信号的时间稳定性。剂量计也被放置在低温恒温器中，以测量低至10 K的时间稳定性的温度依赖性。结果：在PSL刺激光谱中存在强F-带，表明F-中心是KCl：Eu 2+中的电子存储中心，其中电子存储在氯阴离子空位处。由于深能量深度（2.2 eV），F-中心可能不是导致X射线照射后最初几个小时内快速衰减的原因。此外，存在弱的NIR带。然而，在强近红外激发下，PSL稳定率没有变化，表明近红外波段在PSL衰减中没有作用。在低于77 K的温度下，几乎没有信号随时间衰减。在室温下，未掺杂的KCl样品观察到明显的PSL，表明Cl 2 − Vk中心作为未掺杂和掺杂KCl的空穴存储中心，其中空穴被氯分子离子捕获。Vk心在低温下是稳定的，在室温下变得移动的，可能导致观察到的PSL随时间衰减。另一方面，Eu 2+激活剂或晶格中的氧可以稳定Vk中心，从而在PSL中产生稳定的组分。在升高的温度（60 °C或更高）下的热处理能够显著加速迁移过程，导致PSL的快速稳定。结论：热处理使KCl：Eu 2+原型能够在1 h内准备好读出，而不需要应用大的时间依赖性校正因子。然而，这不能使用光学预激发来实现。
Purpose:Current KCl:Eu2+prototype dosimeters require a wait time of 12 h between irradiation and dosimetric readout. Although irradiating the dosimeters in the evening and reading on the following day works well in the clinical schedule, reducing the wait time to few hours is desirable. The purposes of this work are to determine the origin of the unstable charge‐storage centers and to determine if these centers respond to optical or thermal excitation prior to dosimetric readout.Methods:Pellet‐style KCl:Eu2+dosimeters were fabricated in‐house for this study. A 6 MV photon beam was used to irradiate the dosimeters. After x ray irradiation, dosimeters were subjected to external excitation with near‐infrared (NIR) light, ultraviolet (UV) light, or thermal treatment. Photostimulated luminescence (PSL) signal's temporal stability was subsequently measured at room temperature over a few hours using a laboratory PSL readout system. The dosimeters were also placed in a cryostat to measure the temperature dependence of the temporal stability down to 10 K.Results:Strong F‐band was present in the PSL stimulation spectrum, indicating that F‐centers were the electron‐storage centers in KCl:Eu2+where an electron was stored at a chlorine anion vacancy. Due to deep energy‐depth (2.2 eV), F‐centers were probably not responsible for the fast fading in the first a few hours post x ray irradiation. In addition, weak NIR bands were present. However, there was no change in PSL stabilization rate with intense NIR excitation, suggesting that the NIR bands played no role in the PSL fading. At temperatures lower than 77 K there was almost no signal fading with time. Noticeable PSL was observed for undoped KCl samples at room temperature, suggesting that Cl2−Vkcenters served as hole‐storage centers for both undoped and doped KCl where a hole was trapped by a chlorine molecular ion. Vkcenters were stable at low temperature and became mobile at room temperature, probably causing the observed PSL fading with time. On the other hand, Vkcenter could be stabilized by Eu2+activator or oxygen in the lattice, leading to the stable component in the PSL. A thermal process at elevated temperatures (60 °C or higher) was able to significantly accelerate the migration process resulting in a fast stabilization of PSL. However, this could not be accomplished using intense UV excitation.Conclusions:Thermal treatment enables KCl:Eu2+prototypes to be ready for readout in 1 h without the need of applying a large time‐dependent correction factor. However, this cannot be achieved using optical preexcitation.
登录
查看更多内容
通过真空紫外辐射在 BaFBr:Eu2 单晶中创建光刺激中心。
影响因子：
8.6
作者：
Rueter;Seggern;Reininger;Saile
通讯作者：
Saile
光激励透明 KCl:Eu 晶体作为二维紫外线或 X 射线成像传感器的存储材料
影响因子：
3.2
作者：
H. Nanto;K. Murayama;Fumitaka Endo;Y. Hirai;Shin;N. Takeuchi
通讯作者：
N. Takeuchi
室温水合后光激发 X 射线存储磷光体 CsBr:Eu2 的敏化
影响因子：
3.2
作者：
G. Appleby;J. Zimmermann;S. Hesse;O. Karg;H. Seggern
通讯作者：
H. Seggern
Eu掺杂KCl荧光粉晶体作为二维紫外线或X射线成像传感器的存储材料
影响因子：
3.2
作者：
H. Nanto;Fumitaka Endo;Y. Hirai;S. Nasu;S. Taniguchi;N. Takeuchi
通讯作者：
N. Takeuchi
Li共掺杂对CsBr:Eu2辐射硬度的影响
影响因子：
3.2
作者：
J. Zimmermann;S. Hesse;H. Seggern;M. Fuchs;W. Knüpfer
通讯作者：
W. Knüpfer