McNamara Bruce K, O'Hara Matthew J, Casella Andrew M, Carter Jennifer C, Addleman R Shane, MacFarlan Paul J
Pacific Northwest National Laboratory, 902 Battelle Blvd., PO Box 999, Richland, WA 99352, United States.
Pacific Northwest National Laboratory, 902 Battelle Blvd., PO Box 999, Richland, WA 99352, United States.
Talanta. 2016 Jul 1;154:219-27. doi: 10.1016/j.talanta.2016.03.054. Epub 2016 Mar 16.
We report a convenient method for the generation of volatile uranium hexafluoride (UF6) from solid uranium oxides and other U compounds, followed by uniform deposition of low levels of UF6 onto sampling coupons. Under laminar flow conditions, UF6 is shown to interact with surfaces within a fixed reactor geometry to a highly predictable degree. We demonstrate the preparation of U deposits that range between approximately 0.01 and 500ngcm(-2). The data suggest the method can be extended to creating depositions at the sub-picogramcm(-2) level. The isotopic composition of the deposits can be customized by selection of the U source materials and we demonstrate a layering technique whereby two U solids, each with a different isotopic composition, are employed to form successive layers of UF6 on a surface. The result is an ultra-thin deposit that bears an isotopic signature that is a composite of the two U sources. The reported deposition method has direct application to the development of unique analytical standards for nuclear safeguards and forensics. Further, the method allows access to very low atomic or molecular coverages of surfaces.
我们报告了一种从固体铀氧化物和其他铀化合物中生成挥发性六氟化铀（UF6）的简便方法，随后将低水平的UF6均匀沉积到采样试片上。在层流条件下，UF6在固定的反应器几何结构内与表面相互作用，其程度具有高度可预测性。我们展示了制备范围约为0.01至500 ng cm⁻²的铀沉积物的方法。数据表明该方法可扩展到在亚皮克/厘米²水平上进行沉积。沉积物的同位素组成可通过选择铀源材料进行定制，并且我们展示了一种分层技术，即使用两种具有不同同位素组成的铀固体在表面上形成连续的UF6层。结果是形成了一种超薄沉积物，其同位素特征是两种铀源的复合特征。所报道的沉积方法可直接应用于开发用于核保障和法医学的独特分析标准。此外，该方法能够实现极低的原子或分子表面覆盖率。
