Multi-mode horn design and beam characteristics for the Planck satellite
Multi-mode horn design and beam characteristics for the Planck satellite
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DOI：
10.1088/1748-0221/5/04/t04001
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发表时间：
2010-04-01
影响因子：
1.3
通讯作者：
Wylde, R. J.
中科院分区：
文献类型：
--
作者：
Murphy, J. A.;Peacocke, T.;Wylde, R. J.
欧洲航天局的普朗克卫星已经开始以前所未有的灵敏度和高角度分辨率研究整个天空的宇宙微波背景辐射的各向异性。普朗克上的高频仪器（HFI）在100千兆赫到857千兆赫的六个波段同时进行观测。包含非cmb波段允许从数据中健壮地去除前景源。本文研究了以545 GHz和857 GHz为中心的两个最高频率通道的设计、建模和性能预测，这两个通道使用专用的多模馈线喇叭，并专门用于观测这些前景。当不需要衍射极限分辨率时，多模系统的优点是增加了检测组件的吞吐量，从而提高了灵敏度。喇叭配置为背靠背设置，通过滤波器将信号传输到检测器喇叭。天空中宽带波束模式的建模需要仔细分析。当继电器系统中包含检测器喇叭时，喇叭之间复杂的相互作用的模拟在计算上具有挑战性。本文描述了这些高频通道的建模方法，并讨论了如何在溢出、边缘锥度、望远镜孔径照明和天空光束模式方面满足对喇叭设计的光学要求。
The ESA Planck satellite has begun studying the anisotropies of the cosmic microwave background radiation over the whole sky with unprecedented sensitivity and high angular resolution. The High Frequency Instrument, HFI, on Planck is observing simultaneously in six bands in the range 100 GHz to 857 GHz. The inclusion of non-CMB bands allows for robust removal of foreground sources from the data. This paper is concerned with the design, modeling and predicted performances of the two highest frequency channels centered on 545 GHz and 857 GHz, which use specialized multi-mode feedhorns, and are dedicated to observing these foregrounds. Multi-mode systems have the advantage of increasing the throughput, and thus sensitivity, of the detection assembly when diffraction limited resolution is not required. The horns are configured in a back-to-back setup which transmits the signal through filters to a detector horn. The modeling of the broadband beam patterns on the sky is shown to require careful analysis. Simulations of the complex interactions of the horns is computationally challenging when the detector horn in the relay system is included. The paper describes the approach to modeling these high frequency channels and discusses how the optical requirements on the horn designs are met in terms of spillover, edge taper, illumination of the telescope aperture and beam patterns on the sky.