This experiment will be a huge detector 40 meters long and 22 m in diameter, consisting of many different layers of specific
detector types positioned like «onion skins» around the particle collision point.
Observations of blue and red calibration standards measured at various
positions on the
detector (Bohlin et al. 2017) confirm the fidelity of the F814W flat, with aperture photometry consistent to ~ 1 % across the FOV, regardless of spectral
type.