  The New Experiments With Spheres-Gas (NEWS-G) collaboration intends to
achieve $\mathrm{sub-GeV/c^{2}}$ Weakly Interacting Massive Particles (WIMPs)
detection using Spherical Proportional Counters (SPCs). SPCs are gaseous
detectors relying on ionization with a single ionization electron energy
threshold. The latest generation of SPC for direct dark matter searches has
been installed at SNOLAB in Canada in 2021. This article details the different
processes involved in the fabrication of the NEWS-G experiment. Also outlined
in this paper are the mitigation strategies, measurements of radioactivity of
the different components, and estimations of induced background event rates
that were used to quantify and address detector backgrounds.
