Neutral atom imaging mass spectrograph
Neutral atom imaging mass spectrograph
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中性原子成像质谱仪
DOI：
10.1117/12.205660
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
T. S. Stephen
中科院分区：
文献类型：
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作者：
P. Wurz;Matthias R. Aellig;P. Bochsler;A. Ghielmetti;E. Shelley;S. Fuselier;F. Herrero;M. Smith;T. S. Stephen
我们描述了一种利用中性原子遥感测量二维空间等离子体分布的仪器的概念。该仪器在一个维度上进行测量，从旋转的航天器上获得中性通量的2-D(视线)地图。由于我们想要利用这台仪器在磁层中进行测量，所以我们感兴趣的主要物种是动能从大约10 eV到1keV的中性H和O原子。该仪器利用低功函数表面有效地将中性原子转化为负离子。然后，离子被加速离开表面，并通过大口径透镜被带到中间焦点。在进一步加速后，离子被球形静电分析器偏转进入飞行时间质谱仪。器件的质量分辨率足以分辨H、D、He和O。能量和方位角信息是通过对碳箔产生的二次电子进行位置成像获得的。大的几何系数与同时测量角度-能量-质量相结合，消除了循环的需要，并为短时间间隔成像提供了必要的高灵敏度。在旋转的宇宙飞船上，这台仪器能够产生低能中性原子通量的2-D图。
We describe a concept for an instrument to measure 2-D space plasma distributions by remote sensing of neutral atoms. The instrument measures in one dimension, and from a spinning spacecraft one obtains 2-D (line-of-sight) maps of the neutral flux. Because we want to employ this instrument for measurements in the magnetosphere, the main species of interest are neutral H and O atoms with kinetic energies ranging from about 10 eV to 1 keV. The instrument makes use of a low-work-function surface to convert neutral atoms efficiently to negative ions. The ions are then accelerated away from the surface and brought to an intermediate focus by a large aperture lens. After further acceleration, the ions are deflected by a spherical electrostatic analyzer into a time-of-flight mass spectrometer. Mass resolution of the device is sufficient to resolve H, D, He, and O. Energy and azimuth angle information are obtained by position imaging of the secondary electrons produced at the carbon foil. The large geometric factor combined with simultaneous angle-energy-mass measurement eliminates the need for cycling and provides the necessary high sensitivity for imaging at short time intervals. On a spinning spacecraft this instrument is capable of producing 2-D maps of low-energy neutral atom fluxes.