The paper states that this flux is F = 5 x 10^(-6) ergs per square cm per sec 5 x 10^(-13) Joules per square cm per sec
The energy of a photon is E = h * nu = (h * c) / lambda = 3.6 x 10^(-19) Joules = 3.6 x 10^(-12) ergs so the number of photons striking one square cm each second must be N = F / E = 1.38 x 10^6 photons per square cm per sec
If the grains are assumed to be packed in a simple square grid, then N(top) = number of grains across top of 1 square cm = (1 cm) / (2 x 10^(-6) m) = 5000 N(left) = number of grains across left side of 1 square cm = (1 cm) / (2 x 10^(-6) m) = 5000 N(grains) = (number across top) * (number along left edge) = 5000 * 5000 = 25 x 10^(6)
If the N photons hitting each square cm in one second are randomly distributed across the entire square, then the number landing on any particular grain in one second must be N / N(grains) = 1.38 x 10^6 / 25 x 10^6 = 0.055 photons per grain per second
The average interval between successive photons hitting the same grain is just the reciprocal of the number of photons hitting the grain each second. interval = 1 / (0.055 photons per grain per second) = 18 seconds between photons
Copyright © Michael Richmond. This work is licensed under a Creative Commons License.