High-resolution spectra of 20-300 keV hard X-rays from electron precipitation over Antarctica
High-resolution spectra of 20-300 keV hard X-rays from electron precipitation over Antarctica
复制标题
南极洲上空电子沉淀产生的 20-300 keV 硬 X 射线的高分辨率光谱
DOI：
10.1029/95ja01472
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发表时间：
1995
影响因子：
--
通讯作者：
C. M. Johns
中科院分区：
文献类型：
--
作者：
D. Smith;R. Lin;K. Anderson;K. Hurley;C. M. Johns
In December 1990, a set of liquid-nitrogen-cooled germanium hard X-ray and gamma-ray spectrometers was flown aboard a high-altitude balloon from McMurdo, Antarctica, for solar, astrophysical, and terrestrial observations. This flight was the first circumnavigation ({approximately}9-day duration) of the Antarctic continent by a large (800,000-cubic-meter) balloon. Bremsstrahlung hard X-ray emission extending up to {approximately}300 keV, from the precipitation of high-energy electrons, was observed on six separate occasions over the auroral zone, all during low geomagnetic activity (K{sub p}{le} 2+). All events were consistent with emission at the trapping boundary; observation over the polar cap showed no precipitation. The authors present the first high-resolution ({Delta}E {approximately}2 keV) full width at half maximum (FWHM) spectra of this hard X-ray emission in the energy range 20-300 keV. The observed count spectra are deconvolved by model-independent techniques to photon spectra and then to the precipitating electron spectra. The spectral hardness shows all inverse relation with L as expected. This result suggests that high-resolution spectroscopy could be extremely effective in characterizing electron precipitation if coupled with imaging capability. 26 refs., 9 figs., 1 tab.
