Attempts to detect the emission of secondary charged particles in the fission of 235U by slow neutrons

If light charged particles (protons, α-particles, etc.) are emitted during fission, it should be possible to establish this fact by a simple coincidence experiment. Suppose two detectors are arranged so that they can both ‘see’ a thin film of uranium oxide. Let one of the detectors register the entry of fission fragments only, say at the rate of F (sec.-1). Let the other detector register not only fission fragments (unless they are excluded by an interposed absorber) but also light charged particles (protons, a-particles, etc.) with energies within certain limits. Suppose that the rate of registration in the second detector is P (sec.-1), that the mean efficiency for the detection of a light charged particle emitted from the uranium film is e, and that the average number of light charged particles liberated per fission is η.