Ultra-Gaussian horns for ClOVER — a B-Mode CMBexperiment

Ultra-Gaussian horns for ClOVER — a B-Mode CMBexperiment
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ClOVER 的超高斯喇叭 — B 模式 CMB 实验

DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
Jin Zhang
Jin Zhang
中科院分区：
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文献类型：
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作者：
P. Ade;R. Wylde;Jin Zhang

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摘要 — ClOVER 是英国资助的一项实验，位于阿塔卡马沙漠，用于测量 B 模式偏振 20 到 1000 多极之间的宇宙微波背景下降到前景有限的灵敏度。其中之一 两台望远镜将使用 TES 辐射热测量计在 150 和 225 GHz 运行大型焦板阵列。 这些辐射热测量计的馈源采用具有新颖功能的波纹喇叭，满足两个重要的性能 要求：非常低的旁瓣，以避免不受控制的信号污染和高通滤波来控制场 呈现给径向探针探测器。 前者是由圣安德鲁斯的 Graham Smith 开发的设计提供的，旨在故意激发 HE12 高阶 喇叭的正弦方形轮廓部分中的模式，后面是一个扩展的平行部分，旨在使 HE12 模式与主导的 HE1 1 模式同相。令人惊讶的宽带宽 – 达到 30% 的水平 – 旁瓣良好 达到负35dB 以下。分析表明，接近 99.88% 的传输功率（以时间反转的方式）是 在基本高斯自由空间模式中——因此称为“超高斯喇叭”。 后者由靠近进入检测器模块的过渡部分的过滤器部分提供。抑制泄漏远低于 标称 HE 1 1 截止提供了有趣的计算和实验挑战，需要大量 HFSS 和更传统的模式匹配程序中的建模工作。 考虑到预算限制和 需要大量（每个频段 100 个）
Abstract — ClOVER is a UK funded experiment to be based in the Atacama Desert to measure the B-mode polarization of the Cosmic Microwave background between multipoles of 20 and 1000 down to foreground limited sensitivities. One of two telescopes will operate large focal plate arrays at 150 and 225 GHz, using TES bolometers. The feeds to these bolometers utilise corrugated horns with novel features which meet with two important performance requirements: very low sidelobes, to avoid uncontrolled signal contamination and high pass filtering to control the fields presented to the Radial Probe detectors. The former is provide by a design, developed by Graham Smith in St.Andrews, to deliberately excite HE12 higher order modes in a sine-square profile section of the horn, followed by an extended parallel section designed to bring the HE12 mode into phase with the dominate HE1 1 mode. Surprisingly wide bandwidths – at the 30% level - with sidelobes well below minus 35dB are achieved. Analysis shows that close to 99.88% of the transmitted power (in a time reversed view) is in the fundamental Gaussian free space mode – hence the term, Ultra-Gaussian horn. The later is provide by a filter section close to the transition into the detector module. The suppression of leaks well below the nominal HE 1 1 cut-off provided an interesting computational and experimental challenge, requiring significant modelling effort in both HFSS and more traditional Mode Matching programs. Special attention has been applied to the production engineering of these horns – given budgetary constraints and the large number required (100 in each band)