L壳携带旁观空穴的K壳双空穴原子是一类奇异激发态原子。该类原子双电子单光子（TEOP）跃迁Kαα线及其伴线，是研究这类原子能级结构、退激性质及电子-电子关联效应的一种有效“探针”。由于常规的实验手段难以产生高强度的此类原子，高精度Kαα线伴线谱至今尚无有效的实验测量。对这类原子结构和性质的理论认知，急需新的高精度实验数据的推动和检验。HIRFL大科学装置的超导电子回旋共振离子源II能够提供世界上最强的全裸重离子束，为获得高精度Kαα线伴线谱提供了前所未有的机遇。本项目拟利用该装置提供的微安量级的Ne–Ca等全裸离子束，轰击液氮冷却的Be、C靶，得到高强度、K壳双空穴且L壳携带旁观空穴的Ne–Ca原子。采用高分辨X射线晶体谱议，获得这些原子TEOP跃迁Kαα线伴线的能谱结构及分支比（相对于Kαh线伴线），提取这些原子的能级结构和退激性质，研究奇异激发态原子中的电子-电子关联效应。

K-shell hollow atoms with additional vacancies in the L shell are very special atoms, which are in exotic-excited states. The two-electron one-photon (TEOP) transition Kαα lines and their satellite lines provide a useful tool for investigating the energy levels, the decay properties and the electron-electron correlation effects of these kind of atoms. High intensity of these kind of atoms cannot be obtained by conventional experimental methods, and hence a comprehensive measurement on the Kαα satellites with high-resolution has not been obtained so far. The high-resolution spectra are highly needed to understand the atomic structure and other properties of these atoms. The superconducting electron-cyclotron-resonance ion source II of HIRFL can supply the highest current fully stripped heavy ions in the world, which provides an unprecedented opportunity for a comprehensive measurement on Kαα satellite lines with high-resolution. By using the fully stripped Ne–Ca ions extracted from this source with a current of as high as microampere and then bombarding the Be and C target cooled by liquid nitrogen, one aim of the present program is to obtain high intensity Ne–Ca K-shell hollow atoms with additional vacancies in the L shell. By using a high-resolution X-ray wavelength dispersive spectrometer, the energy spectra of the Kαα satellite lines and the branching ratio (to the related satellite lines of the hypersatellite transition Kαh) will be obtained. Emphases will be given to understand the energy levels, decay properties and electron-electron correlation effects of these atoms.