RATIONALE Detecting ice grains with impact ionization mass spectrometers in space provides information about the compositions of ice grains and their sources. Depending on the impact speeds of the ice grains onto the metal target of a mass spectrometer, ionization conditions can vary substantially, resulting in changes to the appearance of the resulting mass spectra. METHODS Here we accurately reproduce mass spectra of water ice grains, recorded with the Cosmic Dust Analyzer (CDA) on board the Cassini spacecraft at typical impact speeds ranging between 4 km/s to 21 km/s, with a laboratory analogue experiment. In this Laser-Induced Liquid Beam Ion Desorption (LILBID) approach, a μm-sized liquid water beam is irradiated with a pulsed infrared laser, desorbing charged analyte and solvent aggregates and isolated ions, which are subsequently analyzed in a time-of-flight (TOF) mass spectrometer. RESULTS We show that our analogue experiment can reproduce impact ionization mass spectra of ice grains obtained over a wide range of impact speeds, aiding the quantitative analyses of mass spectra from space. CONCLUSIONS Spectra libraries created with the LILBID experiment will be a vital tool for inferring the composition of ice grains from mass spectra recorded by both past and future impact ionization mass spectrometers (e.g. the SUrface Dust Analyzer (SUDA) onboard NASA's Europa Clipper Mission or detectors on a future Enceladus Mission).

中文翻译：

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在空间中以不同的撞击速度获得的水冰粒的撞击电离质谱的类似光谱。

理由用太空中的撞击电离质谱仪检测冰粒可提供有关冰粒成分及其来源的信息。根据冰粒对质谱仪金属靶的撞击速度，电离条件可能会发生很大变化，从而导致所得质谱图的外观发生变化。方法在这里，我们通过实验室模拟实验，精确再现了水冰粒的质谱图，该质谱图由卡西尼号航天器上的宇宙尘埃分析仪（CDA）以4 km / s至21 km / s的典型撞击速度记录下来。在这种激光诱导的液束离子解吸（LILBID）方法中，用脉冲红外激光辐照一个微米大小的液态水束，以解吸带电的分析物和溶剂聚集体以及离析的离子，随后在飞行时间（TOF）质谱仪中对其进行分析。结果我们表明，我们的模拟实验可以重现在广泛的撞击速度下获得的冰粒的撞击电离质谱，从而有助于对来自太空的质谱进行定量分析。结论通过LILBID实验创建的光谱库将是从过去和将来的撞击电离质谱仪（例如，NASA欧罗巴Clipper Mission上的表面粉尘分析仪（SUDA）或质谱仪）记录的质谱图中推断冰粒组成的重要工具。未来的土卫二任务）。协助对来自太空的质谱进行定量分析。结论通过LILBID实验创建的光谱库将是从过去和将来的撞击电离质谱仪（例如NASA欧罗巴Clipper Mission上的表面粉尘分析仪（SUDA）或探测器上记录的质谱图）推断冰粒组成的重要工具。未来的土卫二任务）。协助对来自太空的质谱进行定量分析。结论通过LILBID实验创建的光谱库将是从过去和将来的撞击电离质谱仪（例如，NASA欧罗巴Clipper Mission上的表面粉尘分析仪（SUDA）或质谱仪）记录的质谱图中推断冰粒组成的重要工具。未来的土卫二任务）。