FIG. 8.

The saturated Kerr coefficient as a function of the radial position, as calculated with PROM with a maximum electric field of 50 kV/m using 12 basis functions and shot noise based on the intensity, assuming the total number of counts per detector plane is (a) 10⁷, (b) 10⁹, and (c) 10¹² at each sampled plane in ($P$, $Z_{\text{det}}$). Each case is based on 50 samples. The uncertainties are statistical, and based on a coverage factor $k=2$, often called “$2\sigma$,” or 95% confidence.