model of cosmic-ray transport. As a benchmark model, we choose a Navarro-Frenk-White (NFW) dark matter density profile, noting that Einasto and cored-isothermal profiles produce nearly identical results for the [$\overline{\text{D}}~$]{}case [see the discussion in @ibarra2013]: $$\begin{aligned}
\rho_{\text{DM}}(r) = \rho_0 \left( \frac{r_s}{r} \right)^\alpha \frac{1}{(1+r/r_s)^{\alpha+1}}\end{aligned}$$ with inner-slope $\alpha=1$, scale radius $r_s = 24.42$ kpc, and $\rho_0$ chosen to reproduce the dark matter density $\rho_{\odot} = 0.39$ GeV/cm$^3$ at the solar radius $r = 8.5$ kpc [@2010JCAP...08..004C]. For dark matter annihilation at a position $\vec{r}$, the source term for antihelium may then be written as $$\begin{aligned}
Q_{\overline{\text{He}}}(T, \vec{r})=\frac{1}{2}\frac{\rho^2_{\text{DM}}(\vec{r})}{m_{\chi}^2} \langle \sigma v \rangle (1+\epsilon)\frac{dN_{\overline{\text{H3}}}}{dT},\end{aligned}$$ where the $dN/dT$ term is the injection spectrum for tritium found in Section \[sec:production\], $\epsilon$ is the ratio of the production rates of antihelium to tritium (we take $\epsilon$=1 as discussed earlier), and $\langle \sigma v \rangle$ is the thermal annihilation cross-section. The source term must then be propagated from the site of annihilation to Earth. This is typically broken down into two components: (i) interstellar propagation in which the cosmic-rays interact with turbulent Galactic magnetic fields, the interstellar hydrogen and helium, and Galactic winds, and (ii) propagation through the heliosphere, which can significantly deplete the low energy flux as 