Universal molecule injector in liquid helium: Pulsed cryogenic doped helium droplet source
Universal molecule injector in liquid helium: Pulsed cryogenic doped helium droplet source
复制标题
液氦通用分子注射器：脉冲低温掺杂氦液滴源
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
V. Apkarian
中科院分区：
文献类型：
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作者：
V. Ghazarian;J. Eloranta;V. Apkarian
本文报道了用于掺杂散装液氦的通用分子注入器的研制进展。在低温下工作的脉冲阀，低至4 K，在低温恒温器的限制下，在高于液体He稳定水平的蒸汽中工作。通过种子NO2的激光诱导荧光光谱可以看出，该绝缘阀可以在高温下使用预先播种的氦气以超音速膨胀模式运行。在低温操作温度下，膨胀成蒸汽氦产生一个准直的液氦液滴光束，然后用于从低温旋转目标转移到激光烧蚀产生的液体杂质。使用铜作为烧蚀靶，可以可视化操作：液滴光束通过瑞利散射成像，而通过等离子体的光束通过夹带的Cu原子的荧光成像。光束拖着铜离子和电子，铜离子和电子的重新组合控制着f…
Progress toward the construction of a universal molecule injector for doping bulk liquid helium is reported. A pulsed valve that operates at cryogenic temperatures, down to 4 K, is demonstrated within the confinement of a cryostat, operating in the vapor above a steady level of liquid He. The insulated valve can be operated at elevated temperatures with preseeded helium gas in supersonic expansion mode, as demonstrated through laser-induced fluorescence spectra of seeded NO2. At cryogenic operating temperatures, the expansion into vapor helium produces a well-collimated liquid helium droplet beam, which is then used to transfer to the liquid impurities produced by laser ablation from a cryogenic rotating target. The operation can be visualized using copper as the ablation target: the droplet beam is imaged via Rayleigh scattering, while the beam past the plasma is imaged by the fluorescence of the entrained Cu atoms. The beam drags along copper ions and electrons, the recombination of which controls the f...