Heterodyne Instrumentation Upgrade at the Caltech Submillimeter Observatory
Heterodyne Instrumentation Upgrade at the Caltech Submillimeter Observatory
复制标题
加州理工学院亚毫米天文台的外差仪器升级
DOI：
10.1117/12.459114
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发表时间：
2003
影响因子：
4.6
通讯作者：
T. Phillips
中科院分区：
文献类型：
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作者：
J. Kooi;A. Kovács;B. Bumble;G. Chattopadhyay;M. Edgar;Steve Kaye;R. Leduc;J. Zmuidzinas;T. Phillips
加州理工学院亚毫米天文台正在开发一种双偏振、连续比较（相关）接收器。这个仪器在天空上有两束光；参考和信号波束。只使用冷却反射光学，两个极化网格，和一个正交混合耦合器，天空光束耦合到四个无调谐SIS混频器（两个偏振）。4-8 GHz混频器中频输出经过放大后相互关联。原则上，这种技术的结果是平坦的基线和非常低的RMS噪声，特别适合于高红移星系的工作。同时，计划对现有设施外差仪表进行升级。目前正在开发用于230/460 GHz和345/660 GHz大气窗口的双频模式接收机。高频接收器采用平衡配置，既降低了本端功率要求，又降低了噪声。每个混频器有4ghz的中频带宽，可以远程控制。这些变化不仅极大地增强了CSO的光谱能力，而且还使天文台能够集成到哈佛-史密森亚毫米波阵列（SMA）中，作为额外的基线。
Under development at the Caltech Submillimeter Observatory is a dual polarization, continuous comparison (correlation) receiver. The instrument has two beams on the sky; a reference and a signal beam. Using only cooled reflecting optics, two polarizing grids, and a quadrature hybrid coupler, the sky beams are coupled to four tunerless SIS mixers (both polarizations). The 4-8 GHz mixer IF outputs are, after amplification, correlated against each other. In principle, this technique results in flat baselines with very low RMS noise and is especially well suited for high redshift Galaxy work. At the same time an upgrade is planned to the existing facility heterodyne instrumentation. Dual frequency mode receivers are under development for the 230/460 GHz and 345/660 GHz atmospheric windows. The higher frequency receivers are implemented in a balanced configuration, which reduces both the LO power requirement and noise. Each mixer has 4 GHz of IF bandwidth and can be controled remotely. Not only do these changes greatly enhance the spectroscopic capabilities of the CSO, they also enable the observatory to be integrated into the Harvard-Smithsonian Submillimeter Array (SMA) as an additional baseline.