Therefore, the maximum counting rate of any pixel in isolation is 2392 e -/pix/s. However, because simultaneously activated adjacent pixels are assumed to represent the same incident primary electron, if one pixel is counting 2392 e -/pix/s, its 8 adjacent pixels must necessarily be counting 0 e -/pix/s. Therefore, the maximum average counting rate, averaged over a block of pixels is 1/9 the internal counting rate, equating to ~266 e -/pix/s. In practice, the fraction of incident electrons that activate more than one pixel will further reduce this maximum average counting rate. For example, a detection event consisting of two adjacent activated pixels has 10 adjacent inactivated pixels. If all incident primary electrons always activated two adjacent pixels, then the maximum average counting rate would be 2392 / (2 + 10) = ~200 e -/pix/s. Of course, since the shape and size of detection events on the sensor span a range of possibilities, the maximum average counting rate will be a weighted average of all of these possibilities, with the result no more than 266 e -/pix/s.