典型卫星轨道辐射环境及在轨软错误率预计模型分析

使用最新版本的Space Radiation 7.0软件对典型卫星轨道(包括地球同步轨道、中地轨道和低地轨道)的空间辐射环境进行提取和计算,分析不同空间天气和屏蔽条件下的轨道离子通量-能量谱和通量-线性能量沉积(LET)谱特点。以一款SOI SRAM为例,结合地面加速器重离子试验获得的单粒子翻转截面-LET值关系曲线,预计该器件的在轨软错误率(SER),并分析关键参数对预计结果的影响规律和内在机理。结果表明,使用Space Radiation软件的四种输入模式获得的预计结果可相差5倍左右;灵敏区厚度的增大导致在轨SER降低数个数量级,原因为灵敏区厚度的设置与灵敏区平均投影面积和符合条件的空间离子通量的大小直接相关;漏斗长度的大小对预计结果有一定的影响。最后,对SER预计模型的适用性和发展趋势进行了讨论。

Radiation environment of typical satellite orbits and on-orbit soft error rate prediction model analysis

The space radiation environments of typical satellite orbits including geostationary orbit, medium earth orbit, and low earth orbit are extracted and calculated using the latest version of Space Radiation 7.0 toolkit. The ion flux-energy spectrums and flux-LET spectrums under different space weather and shielding conditions are analyzed to reveal the characteristics. Taking an SOI SRAM as an example, combining the SEU cross section versus LET relationship obtained by accelerator-based heavy ions testing, the on-orbit soft error rate is predicted. The influence trend and inner mechanism of key parameters on the prediction results are analyzed. Following results are concluded. Four input modes of Space Radiation software result into soft error rates with difference up to about five orders. The on-orbit soft error rate decreases by several orders of magnitude as the thickness of the sensitive volume increases, which is attributed to the fact that the thickness of the sensitive volume is directly related to the average projected area of the sensitive volume and the qualified space ion flux. The prediction result also depends on the funnel length. Finally, the applicability and development of soft error rate prediction model are discussed.