  The characterization of plasma wakefield acceleration experiments using
emitted photons from betatron radiation requires numerical models in support of
instrumentation of single-shot, double-differential angular-energy spectra.
Precision characterization for relevant experiments necessitates covering a
wide energy range extending from tens of keV through 10~GeV, with an angular
resolution on the order of $100 \;\mu\text{rad}$. In this paper, we present a
numerical model for betatron radiation from plasma accelerated beams, that are
based on integration of Lienard Wiechert (LW) potentials for computed particle
trajectories. The particle trajectories are generated in three different ways:
first, by particle tracking through idealized fields in the blowout regime of
PWFA; second, by obtaining trajectories from the Quasi-static Particle-in-Cell
(PIC) code QuickPIC; and third, by obtaining trajectories from the full PIC
code OSIRIS. We performed various benchmarks with analytical expressions and
the PIC code EPOCH, which uses a Monte-Carlo QED radiation model. Finally, we
present simulations of the expected betatron radiation for parameters from the
Facility for Advanced Accelerator Experimental Tests II (FACET-II) PWFA and
plasma photocathode experiments.
