UBC Theses and Dissertations
Complex gain modeling of CHIME’s coaxial cables Guliani, Sidhant
CHIME is a new radio interferometer located at the Dominion Radio Astrophysical Observatory (DRAO) in Penticton, BC. The primary goal of CHIME is to constrain the dark energy equation of state by measuring the expansion history of the Universe using the Baryon Acoustic Oscillation (BAO) scale as a standard ruler. CHIME consists of 4 cylindrical reflectors, each populated with 256 dual-polarization antennas along its focal-line. Prior to digitization, each signal chain consists of a low noise amplifier, 50m of coaxial cable, and a filter amplifier. In order to obtain accurate interferometric imaging, we need to determine the relative complex gain (amplitude and phase vs. frequency) of each analog chain to 0.3%. The complex gain of each receiver depends primarily on temperature. This thesis discusses efforts to construct a thermal model of the CHIME’s coaxial cables that will allow us to meet our calibration requirements.
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