Correlation between adjacent pixels during counting means the Apollo, with an internal count rate of 2392 e -/pix/s, has an effective counting rate of ~266 e -/pix/s. Given that effective count rate, a true incident flux of 96 e -/s on a pixel would result in only ~80 e -/s being counted (Figure ). Conversely, if less than 80 e -/pix/s are detected, CL is expected to be lower than 20 %. For example, if 10 e-/pix/s are detected, an average loss of less than 1 e -/pix/s is expected (Figure ). These calculations set important bounds for signal counts at reflections and ultimately, for incident beam flux on a crystal.