arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2603.02016astro-ph.IM
收藏

提克纳微波光谱仪中频谱测量的系统误差

Systematic errors in spectral measurements with the Tenerife Microwave Spectrometer

Instituto de Astrofisica de Canarias (IAC)（加那利天体物理研究所）；Universidad de La Laguna（拉古纳大学）；Istituto Nazionale di Astrofisica（意大利国家天体物理研究所）

A. M. Arriero-Lopez, J. A. Rubiño-Martín, F. Cuttaia, L. Terenzi, R. Hoyland

阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

AI总结：

本文研究了提克纳微波光谱仪中频谱测量的系统误差，通过分析仪器模型和噪声温度贡献，量化了非理想混叠效应的影响，并建立了校准和性能优化的框架。

摘要：

我们介绍了TMS辐射计的分析仪器模型，这是一种伪相关系统，旨在通过连续比较天空和参考负载信号来实现绝对天空温度测量。本工作的目标是量化并理解影响绝对辐射测量的固有非理想因素的影响。我们结合了Jones矩阵形式，用于描述不同仪器组件中的非理想信号混叠效应，以及Friis形式，用于考虑噪声温度贡献，这些贡献引入了特定的偏移项。该模型包括从低温恒温器入口窗口开始的所有组件，使我们能够通过系统传播现实的损耗、回波损耗和噪声因子。我们发现非理想混叠效应，如强度到极化和天空到负载泄漏，预计在百分比水平出现，但原则上可以校准消除。TMS强度响应表现出频率依赖的偏移，其带平均水平为6.9 K，主要由低温恒温器窗口引起，而红外滤波器和正交模式转换器则贡献较小。在要求的TMS热稳定性为1 mK每小时的情况下，输出信号的变化可达到91.3 mK，这设定了绝对天空温度精度的基本限制。相比之下，在10-20 GHz频段内的相对频谱测量在几微开尔文的水平上是稳定的，与仪器目标灵敏度约为10 Jy/sr一致。本工作提供了对影响绝对辐射测量的系统效应的详细和定量评估，并建立了TMS仪器校准和性能优化的稳健框架。

英文摘要：

We present an analytical instrument model of the TMS radiometer, a pseudo-correlation system designed for absolute sky-temperature measurements through a continuous comparison between sky and reference-load signals. The goal of this work is to quantify and understand the impact of instrumental non-idealities that are intrinsic to absolute radiometric measurements. We used a combination of the Jones-matrix formalism, to describe non-ideal signal mixing effects in the different instrument components, and the Friis formalism, to account for noise-temperature contributions which introduce specific offset terms. The model includes all components from the cryostat entrance window onwards and allows us to propagate realistic losses, return losses, and noise figures through the system. We find that non-ideal mixing effects, such as intensity-to-polarization and sky-to-load leakage, are expected to appear at the percent level, but they could be in principle calibrated out. The total TMS intensity response exhibits a frequency-dependent offset with a band-averaged level of 6.9 K, dominated by the cryostat window, and with smaller contributions from the infrared filter and orthomode transducers. Under the required TMS thermal stability of 1 mK over one hour, the resulting variation in the output signal can reach up to 91.3 mK, which sets the fundamental limit on the absolute sky-temperature accuracy. In contrast, relative spectral measurements across the 10-20 GHz band are stable at the few-microkelvin level, consistent with the instrument target sensitivity of ~ 10 Jy/sr. This work provides a detailed and quantitative assessment of the systematic effects affecting absolute radiometric measurements and establishes a robust framework for the calibration and performance optimization of the TMS instrument.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑