CHARM: a room-temperature 345GHz receiver for the Large Millimeter Telescope
CHARM: a room-temperature 345GHz receiver for the Large Millimeter Telescope
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CHARM：用于大型毫米波望远镜的室温 345GHz 接收器
DOI：
10.1117/12.2561877
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
Colín-Beltrán E
中科院分区：
文献类型：
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作者：
Colín-Beltrán E
在墨西哥Sierra Negra的大型毫米波望远镜上安装了一台使用次谐波肖特基势垒二极管混频器的345 GHz室温单像素外差接收机。该接收器于2013年在英国科学和技术设施理事会卢瑟福阿普尔顿实验室开发，用于在312 GHz和360 GHz之间进行地基大气研究。在STFC全球挑战研究基金（GCRF）项目“天文系统培训，工程和合作（ASTEC）”的支持下，该仪器已被重新配置以支持天文研究，并安装在50米LMT上，用作亚毫米波长观测的探路者。这种新的接收机，CHARM（墨西哥合作外差天文接收机），已经交换了原来实现的单边带混频器设计的双边带设备。此外，还安装了带宽更宽的中频链、额外的数字采样光谱仪和适当的接口准光学器件。这些修改导致了一个交钥匙接收机系统，其双边带（DSB）接收机噪声温度（Trec）在实验室中测量为~1200 K。该仪器包括一个更宽的中频和总共四个数字频谱仪，包括12 GHz中频带宽和1.46 MHz分辨率。肖特基混频器的使用允许室温操作，并且当与低温超导系统相比时，虽然这两个属性都牺牲了噪声性能，并且因此牺牲了检测灵敏度，但是它们允许实现相对简单的系统架构，该系统架构具有建立LMT亚毫米波性能潜力和相关质量的局部大气“看见”条件的目标。该仪器的详细设计，LMT适应和第一光的结果的光学系统的描述。
A 345 GHz room-temperature single-pixel heterodyne receiver using sub-harmonic Schottky barrier diode mixers has been installed at the Large Millimeter Telescope (LMT) on the Sierra Negra in Mexico. The receiver was developed at the Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory (RAL) in the UK in 2013 to perform ground-based atmospheric studies between 312 GHz and 360 GHz. With support from the STFC Global Challenge Research Fund (GCRF) project “Astronomical System Training, Engineering and Collaboration (ASTEC)” the instrument has been reconfigured to support astronomical research and installed on the 50-meter LMT to be used as a pathfinder for sub-millimeter wavelength observations. This new receiver, CHARM (Collaborative Heterodyne Astronomical Receiver for Mexico), has exchanged an originally implemented single-sideband mixer design for a double-sideband device. In addition, a broader bandwidth intermediate frequency (IF) chain, additional digital sampling spectrometers and appropriate interface quasi-optics have been installed. The modifications have resulted in a turnkey receiver system with a double sideband (DSB) receiver noise temperature (Trec) of ~1200 K as measured in the laboratory. The inclusion of a wider IF and a total of four digital spectrometers the instrument encompasses a 12 GHz IF bandwidth with 1.46 MHz resolution. Use of Schottky mixers allows room temperature operation and whilst both of these attributes sacrifice noise performance, and thus detection sensitivity, when compared with cryogenic superconducting systems, they allow a relatively simple system architecture to be implemented that has objective of establishing the LMT sub-millimeter wave performance potential and related quality local atmospheric ‘seeing’ conditions. The detailed design of the instrument, description of the optical system for the LMT adaptation and first-light results are presented.