Electronics Instrumentation for the Greenland Telescope
Abstract
The Greenland Telescope project has recently participated in an experiment to image the supermassive black hole shadow at the center of M87 using Very Long Baseline Interferometry technique in April of 2018. The antenna consists of the 12-m ALMA North American prototype antenna that was modified to support two auxiliary side containers and to withstand an extremely cold environment. The telescope is currently at Thule Air Base in Greenland with the long-term goal to move the telescope over the Greenland ice sheet to Summit Station. The GLT currently has a single cryostat which houses three dual polarization receivers that cover 84-96 GHz, 213-243 GHz and 271-377 GHz bands. A hydrogen maser frequency source in conjunction with high frequency synthesizers are used to generate the local oscillator references for the receivers. The intermediate frequency outputs of each receiver cover 4-8 GHz and are heterodyned to baseband for digitization within a set of ROACH-2 units then formatted for recording onto Mark-6 data recorders. A separate set of ROACH-2 units operating in parallel provides the function of auto-correlation for real-time spectral analysis. Due to the stringent instrumental stability requirements for interferometry a diagnostic test system was incorporated into the design. Tying all of the above equipment together is the fiber optic system designed to operate in a low temperature environment and scalable to accommodate a larger distance between the control module and telescope for Summit Station. A report on the progress of the above electronics instrumentation system will be provided.
Cite
@article{arxiv.1806.07525,
title = {Electronics Instrumentation for the Greenland Telescope},
author = {Derek Kubo and Chih-Chiang Han and Hiroaki Nishioka and Ryan Chilson and Ranjani Srinivasan and Sheng- Feng Yen and Kuo-Chieh Fu and Homin Jiang and Kuan-Yu Liu and Ta-Shun Wei and Chih-Wei Huang and Chen- Yu Yu and Peter Oshiro and Shu-Hao Chang and Chung-Cheng Chen and Philippe Raffin and Yau-De Huang and Pierre Martin-Cocher and Ming-Tang Chen and Makoto Inoue and Satoki Matsushita and Keiichi Asada and Shoko Koyama and Patrick Koch and Paul T. P. Ho and Yang-Tai Shaw and Timothy J. Norton and Nimesh A. Patel and Shepherd S. Doeleman and Daniel Bintley and Craig Walther and Per Friberg and Jessica Dempsey and Hideo Ogawa and Kimihiro Kimura and Yutaka Hasegawa and Ching-Tang Liu and Kou-Chang Han and Song-Chu Chang and Li-Ming Lu},
journal= {arXiv preprint arXiv:1806.07525},
year = {2018}
}
Comments
19 pages, 37 figures, oral presentation at the June 2018 SPIE conference: Astronomical Telescopes + Instrumentation, in the section on Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX