Fission transient times from fission probabilities of neighboring isotopes

We present a new and straightforward method to estimate the fission transient time by utilizing the cumulative fission probabilities of neighboring isotopes. The fission probabilities were determined as the ratio of the measured fission cross sections to the Bass Model fusion cross sections. For five neighboring 185–189Os compound nuclei produced in 3He/4He-induced reactions on separated isotope W targets, the transient time τD is estimated to be <25×10−21 seconds for excitation energies less than 150 MeV, and the most likely value of τD is ≈10×10−21 seconds.