应用天文研究组知识库

提出了将超导纳米线单光子探测器(SSPD)应用于空间碎片激光测距的构想,并通过理论分析和等效外场实验进行了可行性论证。根据SSPD在门控时间内允许多次测量的特性,建立了信噪比随回波光子数的变化模型,并考察了激光器发射重复频率、天光背景噪声强度、探测器暗计数率等参数对信噪比的影响,结合回波光子数方程和噪声强度,以云南天文台激光测距系统为例,推算出该系统具备探测830 km处米级大小空间碎片的能力。结合光纤耦合条件,设计了以太阳能板为目标的外场实验,通过改变光学系统透过率,获得了信噪比随回波光子数变化的实验曲线,验证了利用信噪比变化推测系统作用距离方法的有效性,理论和等效实验结果均表明超导纳米线探测器有望实现空间碎片激光测距。

Space debris detection using superconducting nanowire single-photon detector (SSPD) as detectors is proposed and both theoretically and equivalent experimentally verified. The multi-detection characteristic of SSPD during gating period is analyzed, and the signal noise ratio (SNR) model with echo photon number is established. Effects of laser repetition rate, sky background noise rate and dark count rate of SSPD on SNR are discussed. Taking the kHz laser ranging system of Yunnan Observatories as an example, combined with the echo photon number equation, it implies that the kHz laser ranging system at Yunnan Observatories has the capability for 1 m²space debris detection from 830 km away. Considering the fiber coupling requirement, an experimental curve of SNR versus echo number is obtained, which verifies the proposed method. Both theoretical and experimental results show that SSPD has the potential for space debris laserranging.