This paper presents the development, testing, and early operation of a space-borne instrument that can measure and identify charged particles and neutrals in the energy range of 20–400 keV with a 6.25 keV energy resolution. The instrument generates electric fields perpendicular to its entrance aperture, which allows it to identify electrons, ions, and neutrals by deflecting the trajectories of charged particles along the direction of the electric fields. Four identical detector pixels with thin windows, relatively positioned along the direction of the electric fields, independently measure each energy distribution of particles with a total geometric factor of approximately 0.01 cm²·sr. In addition, to measure higher particle fluxes, up to 10⁹/(cm²∙sr∙s), a reduction in particle fluxes by a factor of ∼100 is possible with a mechanical attenuator. Two identical telescopes, each with a field-of-view of 15° × 70°, are orthogonally placed to measure particles with different pitch angles relative to local magnetic fields. The test results of the flight model instrument against laboratory radioisotopes, ²⁴¹Am, ¹³³Ba, and ¹⁴C, are provided, together with results from a numerical simulation to estimate the instrument’s performance. The instrument capabilities are successfully demonstrated with energy spectra of particle distributions acquired from in-orbit operations.

本文介绍了一种星载仪器的开发、测试和早期操作，该仪器可以测量和识别 20-400 keV 能量范围内的带电粒子和中性粒子，能量分辨率为 6.25 keV。该仪器产生垂直于其入口孔径的电场，这使其能够通过沿电场方向偏转带电粒子的轨迹来识别电子、离子和中性物质。四个相同的带有薄窗的探测器像素，沿电场方向相对定位，独立地测量粒子的每个能量分布，总几何因子约为 0.01 cm ² ·sr。此外，为了测量更高的粒子通量，高达 10 ⁹ /(cm ²∙sr∙s)，使用机械衰减器可以将粒子通量降低约 100 倍。两个相同的望远镜，每个都有 15° × 70° 的视场，正交放置以测量相对于局部磁场具有不同俯仰角的粒子。提供了飞行模型仪器对实验室放射性同位素²⁴¹ Am、¹³³ Ba 和¹⁴ C的测试结果，以及估算仪器性能的数值模拟结果。通过在轨操作获得的粒子分布的能谱，成功证明了仪器的能力。