Fig. 4: Schematic layouts for the actual, idealized and virtual radioactive random number generators (RNGs).
From: Secure random number generation from parity symmetric radiations
Panel (a) on the left shows the side view of our radioactive RNG. We assume that the detector D is housed within one (the lower) hemisphere (condition (B)). Panels (b), (c) and (d) depict theoretical models introduced for simplifying the description of the security proof, although these three never need to be implemented in practice. Panel (b) depicts the idealized setting satisfying conditions (A') and (B'), where the detector D alone can determine the direction, up or down, of the emitted particle. Similarly, panel (c) depicts the setting with two idealized detectors placed above and below the source. The layout given in (c) is, in effect, equivalent to the that given in (b) of the virtual RNG using two ideal detectors. Likewise, the layout depicted in (d) describes the virtual RNGs corresponding to the case (a).
