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首页> 外文会议>International Conference on Synchrotron Radiation Instrumentation >Superconducting High-Resolution X-Ray Spectrometers For Chemical State Analysis Of Dilute Samples
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Superconducting High-Resolution X-Ray Spectrometers For Chemical State Analysis Of Dilute Samples

机译：超导高分辨率X射线光谱仪，用于稀释样品的化学质态分析

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Cryogenic X-ray spectrometers operating at temperatures below 1 K combine high energy resolution with broadband efficiency for X-ray energies up to 10 keV. They offer advantages for chemical state analysis of dilute samples by fluorescence-detected X-ray absorption spectroscopy (XAS) in cases where conventional Ge or Si(Li) detectors lack energy resolution and grating spectrometers lack detection efficiency. We are developing soft X-ray spectrometers based on superconducting Nb-Al-AlOx-Al-Nb tunnel junction (STJ) technology. X-rays absorbed in one of the superconducting electrodes generate excess charge carriers in proportion to their energy, thereby producing a measurable temporary increase in tunneling current. For STJ operation at the synchrotron, we have designed a two-stage adiabatic demagnetization refrigerator (ADR) with a cold finger that holds a 3 × 3 array of STJs inside the UHV sample chamber at a temperature of ～0.1 K within ～15 mm of a room temperature sample. Our STJ spectrometer can have an energy resolution below 10 eV FWHM for X-ray energies up to 1 keV, and has total count rate capabilities above 100,000 counts/s. We will describe detector performance in synchrotron-based X-ray fluorescence experiments and demonstrate its use for XAS on a dilute metal site in a metalloprotein.
机译：低于1 k温度操作的低温X射线光谱仪与X射线能量高达10keV的宽带效率合并高能量分辨率。它们提供了通过荧光检测到的X射线吸收光谱（XAS）对稀释样品进行化学状态分析的优点，因为传统的GE或Si（Li）探测器缺乏能量分辨率和光栅光谱仪缺乏检测效率。我们基于超导Nb-Al-Alox-Al-Nb隧道结（STJ）技术开发软X射线光谱仪。在其中一个超导电极中吸收的X射线以与它们的能量成比例地产生过量的电荷载体，从而产生可测量的隧道电流暂时增加。对于Syschrotron的STJ操作，我们设计了一种双级绝热退磁冰箱（ADR），冷手指在UHV样品室内的3×3阵列的STJ，在〜15mm内的温度〜0.1k室温样品。我们的STJ光谱仪可以具有低于10 EV FWHM的能量分辨率，用于X射线能量，高达1 keV，并且具有高于100,000计数/秒的总计数能力。我们将描述在基于同步的X射线荧光实验中的检测器性能，并证明其在金属蛋白中的稀释金属位点上的XAs使用。

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