Errors in Deep Dish Development Array (6m) construction and metrology steps

Mohammad Nouroz N. Islam; Deniz Ölçek; Gordon Lacy; Hsin Cynthia Chiang; Richard Hellyer

doi:10.1117/12.2629423

26 August 2022 Errors in Deep Dish Development Array (6m) construction and metrology steps

Mohammad Nouroz N. Islam, Deniz Ölçek, Gordon Lacy, Hsin Cynthia Chiang, Richard Hellyer

Proceedings Volume 12182, Ground-based and Airborne Telescopes IX; 121820F (2022) https://doi.org/10.1117/12.2629423
Event: SPIE Astronomical Telescopes + Instrumentation, 2022, Montréal, Québec, Canada

Abstract

In this article, we present a model describing the mechanical error stack-up and pointing analysis for primary focus radio arrays and summarize our metrology and simulation results. The mathematical framework of the error model is especially formulated for the Deep Dish Development Array 6-m (D3A6) which is a small interferometric radio telescope being deployed at the Dominion Radio Astrophysical Observatory (DRAO) site. The 3-element D3A6 will serve as a test bed for the upcoming Canadian Hydrogen Observatory and Radio-transient Detector (CHORD) project which will survey the northern sky to measure baryon acoustic oscillations (BAO) observing the 21 cm hyper-fine transition of neutral hydrogen. CHORD will complete similar surveys done by Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) in the southern hemisphere. All the mechanical error modelling and metrology steps presented here will similarly be used and beneficial for the upcoming CHORD array. Using a Monte Carlo analysis pipeline based on this error propagation model, we study if our mechanical requirements should be tighten or relaxed and how the assembly and alignment of the D3A6 should be adjusted. The dishes are made out of fiber glass composites with metal reflectors embedded in them. Vacuum infusion process is used to fabricate the dishes from a precision mold. The mean mold RMS is measured as 0.54 mm RMS. The dish surface mean RMS error is 0.68 mm with a precision of 0.09 mm obtained from the 3 dishes. The mean boresight error is 21.72 arcmin with a precision of 5.44 arcmin. The study presents the metrology methods and errors obtained from the dish fabrication, assembly of the telescope components, alignment of the dishes. The study provides an insight on the errors and their specified requirement towards the development of CHORD array.

Conference Presentation

Citation Download Citation

Mohammad Nouroz N. Islam, Deniz Ölçek, Gordon Lacy, Hsin Cynthia Chiang, and Richard Hellyer "Errors in Deep Dish Development Array (6m) construction and metrology steps", Proc. SPIE 12182, Ground-based and Airborne Telescopes IX, 121820F (26 August 2022); https://doi.org/10.1117/12.2629423

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