The cosmology large angular scale surveyor (CLASS): 40 GHz optical design
The cosmology large angular scale surveyor (CLASS): 40 GHz optical design
复制标题
宇宙学大角度尺度测量仪（CLASS）：40 GHz 光学设计
DOI：
10.1117/12.925464
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发表时间：
2012
期刊：
影响因子：
1.9
通讯作者：
L. Zeng
中科院分区：
文献类型：
--
作者：
J. Eimer;C. Bennett;D. Chuss;T. Marriage;Edward J. Wollack;L. Zeng
宇宙学大角尺度测量仪 (CLASS) 仪器将测量智利北部阿塔卡马沙漠托科山 40、90 和 150 GHz 宇宙微波背景的偏振。在本文中，我们描述了 40 GHz 望远镜系统的光学设计。该望远镜采用衍射极限折反射设计，由前端可变延迟偏振调制器 (VPM)、两个环境温度反射镜、两个低温介电透镜、热阻滤波器和 36 个光滑壁标量馈角天线阵列组成。馈源喇叭将信号引导至天线耦合过渡边缘传感器 (TES) 测辐射热计。偏振双工和带通定义在与 TES 相同的微芯片上处理。馈源喇叭光束被 4 K Lyot 光阑截断为 10 dB 边缘锥度，以限制杂散光对探测器的负载并控制前端 VPM 的边缘照明。视场为 19° x 14°，天空中每束光束的分辨率为 1.5° FWHM。
The Cosmology Large Angular Scale Surveyor (CLASS) instrument will measure the polarization of the cosmic microwave background at 40, 90, and 150 GHz from Cerro Toco in the Atacama desert of northern Chile. In this paper, we describe the optical design of the 40 GHz telescope system. The telescope is a diffraction limited catadioptric design consisting of a front-end Variable-delay Polarization Modulator (VPM), two ambient temperature mirrors, two cryogenic dielectric lenses, thermal blocking filters, and an array of 36 smooth-wall scalar feedhorn antennas. The feed horns guide the signal to antenna-coupled transition-edge sensor (TES) bolometers. Polarization diplexing and bandpass definition are handled on the same microchip as the TES. The feed horn beams are truncated with 10 dB edge taper by a 4 K Lyot-stop to limit detector loading from stray light and control the edge illumination of the front-end VPM. The field-of-view is 19° x 14° with a resolution for each beam on the sky of 1.5° FWHM.