分类： 核科学技术 >> 核科学与技术 提交时间： 2024-05-11
摘要： The Dynamics beamline (D-Line), which combines synchrotron radiation infrared spectroscopy (SR-IR) and energy-dispersive X-ray absorption spectroscopy (ED-XAS), is the first beamline in the world to realize concurrent ED-XAS and SR-IR measurements at the same sample position on a millisecond time-resolved scale. This combined technique is effective for investigating rapid structural changes in atoms, electrons, and molecules in complicated disorder systems, such as those used in physics, chemistry, materials science, and extreme conditions. Moreover, ED-XAS and SR-IR can be used independently in the two branches of the D-Line. The ED-XAS branch is the first ED-XAS beamline in China, which uses a tapered undulator light source and can achieve approximately 2.5 × 1012 photons/s•300 eV BW@7.2 keV at the sample position. An exchangeable polychromator operating in the Bragg-reflection or Laue-transmission configuration is used in different energy ranges to satisfy the requirements for beam size and energy resolution. The focused beam size is approximately 3.5 μm (H) × 21.5 μm (V), and the X-ray energy range is 5–25 keV. Using one- and two-dimensional position-sensitive detectors with frame rates of up to 400 kHz enables time resolutions of tens of microseconds to be realized. Several distinctive techniques, such as the concurrent measurement of in-situ ED-XAS and infrared spectroscopy, time-resolved ED-XAS, high-pressure ED-XAS, XMCD, and pump–probe ED-XAS, can be applied to achieve different scientific goals.
分类： 物理学 >> 核物理学 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
CAI Xiao-Lu
FAN Guang-Wei
XU Hang-hua
AN Zhen-Dong
FAN Gong-Tao
XU Ben-Ji
LI Yong-Jiang
Pan Qiang-Yan
YAN Zhe
XU Wang
摘要： The ambiguity of the structure of 12Be especially in the configuration of 12Be ground state has attracted a lot of attention recently. We notice that the nuclear reaction cross section R at low energy region is sensitive to the surface structure of 12Be, which is greatly impacted by the ground state configuration of 12Be especially by the occupancy probability of the s orbital component. By using existed interaction cross section data of 12Be on C at 790 MeV/nucleon and Glauber model, the upper limit of the s orbital occupation probability of 12Be ground state is roughly determined to be about 56% with Single Particle Model calculations. This demonstrates that the method is very promising to determine the s orbital component of 12Be with proper nuclear-matter density distribution calculations for different orbitals of 12Be ground state. Hence we bring forward to determine the s orbital component of 12Be by measuring the R of 12Be on C and Al at several tens of MeV/nucleon. In this paper, the feasibility and detailed experimental scheme of the R measurement are carefully studied. The precision of the s orbital occupation probability of 12Be ground state is expected to achieve 9% by using the proposed 2% R data.
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