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Sophia Da Costa

Publications and source records attributed to Sophia Da Costa.

2 recordsLinked to original sources
arXiv2026

Low-cost, ultra-wideband, differential low-noise amplifier for interferometric radio telescopes

We present a low-cost, ultra-wideband, dual-polarized differential low-noise amplifier that eliminates the need for a pre-amplification balun. Built entirely from commercial surface-mount components, the design costs approximately 20 US dollars per unit. The amplifier has been characterized through laboratory gain and noise measurements together with feed-coupled hot-cold testing at the Dominion Radio Astrophysical Observatory. A noise figure close to 0.3 dB is demonstrated across a 10:1 bandwidth when matched to a constant 130 $Ω$ source, while feed-coupled measurements yield system noise temperatures as low as 25 K when matched to a Vivaldi feed operating over a 300-1500 MHz bandwidth.

astro-ph.IM↗
arXiv2026

Overview of the Canadian Hydrogen Observatory and Radio Transient Detector (CHORD) Project

The Canadian Hydrogen Observatory and Radio-transient Detector (CHORD) is a next-generation wideband radio interferometer currently being constructed and commissioned at the Dominion Radio Astrophysical Observatory in British Columbia, Canada. CHORD is designed for precision 21\,cm cosmology, fast radio transient discovery, spectral line galaxy surveys, and pulsar science using a highly redundant large-N, small-diameter drift-scan array architecture. The telescope consists of a 512-element core array of 6\,m dishes operating from 300--1500\,MHz in drift-scan mode, together with two 64-dish outrigger stations located at the Hat Creek Radio Observatory and the Green Bank Observatory for long-baseline transient localization. The instrument supports multiple simultaneous digital backends for interferometric correlation, FRB detection, pulsar beamforming, and high spectral resolution surveys. CHORD is designed with an emphasis on precision beam control and stable instrumental response, incorporating lessons learned from the Canadian Hydrogen Intensity Mapping Experiment (CHIME) while providing a substantial increase in sensitivity. Initial performance has been evaluated using a three-dish engineering array, and a 64-dish pathfinder array is currently being commissioned. The full array will be commissioned in 2028.

astro-ph.IM↗