The soft X‐ray region below 200 eV is important for investigating chemical and biological phenomena since it covers K ‐edges of Li and B and L ‐edges of Si, P, S and Cl. Helium gas is generally used as the soft X‐ray transmission window for soft X‐ray absorption spectroscopy (XAS) under atmospheric conditions. However, the helium gas window cannot be applied to XAS in the low‐energy region since transmitted soft X‐rays mostly consist of high‐order X‐rays due to the low transmission of first‐order X‐rays. In this study, the argon gas window is proposed as a new soft X‐ray transmission window in the low‐energy region. High‐order X‐rays are removed by the absorption of the Ar L ‐edge (240 eV), and first‐order X‐rays become the major contribution of transmitted soft X‐rays in the low‐energy region. Under atmospheric argon conditions, the double‐excitation Rydberg series of helium gas (60 eV), Si L ‐edge XAS of an Si₃N₄ membrane (100 eV) and S L ‐edge XAS of dimethyl sulfoxide gas (170 eV) are successfully measured, indicating that the argon gas window is effective for soft X‐ray transmission in the low‐energy region from 60 eV to 240 eV.

中文翻译：

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使用氩气窗口探索低能区的软 X 射线吸收光谱

200 eV 以下的软 X 射线区域对于研究化学和生物现象非常重要，因为它覆盖了Li 的K边以及 Si、P、S 和 Cl 的 B 和L边。氦气通常用作大气条件下软X射线吸收光谱（XAS）的软X射线传输窗口。然而，氦气窗口不能应用于低能区的XAS，因为由于一阶X射线的透射率较低，透射的软X射线主要由高阶X射线组成。在这项研究中，氩气窗被提出作为低能区的一种新的软X射线透射窗。高阶 X 射线被 Ar L边（240 eV）的吸收去除，一阶 X 射线成为低能区透射软 X 射线的主要贡献。在氩气条件下，氦气（60 eV）的双激发里德伯级数、 Si ₃ N _{4膜的 Si} L边 XAS （100 eV）和二甲亚砜气体（170 eV）的S L边 XAS 为成功测量，表明氩气窗口对于60 eV至240 eV低能区的软X射线传输是有效的。