Abstract：
A new method for radionuclide labeling by the use of graphene thin films was previously presented. In this work, a comparison among low energy radioactive sources supported on carbonaceous thin films on polyvinyl chloride-polyvinyl acetate copolymer (VYNS), based on the use of aqueous solutions is investigated as a feasible alternative to the traditional metallized films avoiding the downside of the loss of many broken films. Graphene-based materials were prepared by both oxidation-exfoliation-reduction and direct graphite exfoliation routes. In addition, multiwalled carbon nanotubes (MWCNTs) thin films were also evaluated. The stability of both carbonaceous materials aqueous dispersions were studied by using ionic and non-ionic surfactants. Solid carbon-based materials were characterized by X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) whereas the colloidal nature of the aqueous dispersions was verified by the measurement of Tyndall effect and the morphology of thin films was evaluated by Scanning Electron Microscopy (SEM). 55Fe solutions were used to prepare the radioactive sources on the thin films by quantitative drop deposition. The quality of spectra was measured in a pressurized proportional counter. Results showed a resolution higher than 0.9 keV for all the tested sources. However, MWCNT-based along with non-surfactant sources presented non-adequate escape peaks and low energy tails. On the contrary, all the graphene-based sources prepared using surfactants to stabilize aqueous solutions presented an energy resolution comparable to that of the metallized source while offering notable advantages in terms of cost efficiency and reliability of the as-prepared supports.
摘要：
先前提出了一种通过使用石墨烯薄膜进行放射性核素标记的新方法。在这项工作中,在聚氯乙烯-聚乙酸乙烯酯共聚物（VYNS）上的碳质薄膜上支撑的低能放射源之间的比较，基于水溶液的使用进行了研究，作为传统金属化薄膜的可行替代方案，避免了许多破碎薄膜的损失。通过氧化-剥离-还原和直接石墨剥离两种途径制备了基于石墨烯的材料。此外,还评估了多壁碳纳米管（MWCNT）薄膜。通过使用离子和非离子表面活性剂研究了两种碳质材料水分散体的稳定性。固体碳基材料通过X射线衍射（XRD）和傅立叶变换红外光谱（FTIR）进行表征，而水性分散体的胶体性质通过Tyndall效应的测量进行验证，薄膜的形态通过扫描电子显微镜（SEM）进行评估。55Fe溶液用于通过定量液滴沉积在薄膜上制备放射源。在加压比例计数器中测量光谱的质量。结果表明，所有测试源的分辨率均高于0.9keV。然而,基于MWCNT的以及非表面活性剂来源呈现不充分的逃逸峰和低能量尾部。相反,使用表面活性剂稳定水溶液制备的所有基于石墨烯的来源呈现与金属化来源相当的能量分辨率,同时在制备的载体的成本效率和可靠性方面提供显著优势。
