Probing fission fragment angular momenta by photon measurements
J. Randrup, T. Døssing, R. Vogt
Abstract
We discuss how the measurement of photon angular correlations can reveal information about the orientation of the fission fragment angular momenta. Photons from identified stretched $E2$ collective transitions in even-even fission product nuclei are particularly suitable because they do not affect the orientation of the nuclear spin. Their angular distribution relative to the direction of a fission fragment may reveal the orientation of the fragment spins relative to the fission axis. A novel means of probing the correlated fission fragment spins is the distribution of the opening angle between $E2$ photons from even-even partner fragments which reveals the mutual correlation of the fragment spins, if the photon helicities can be determined, demonstrating the potential power of helicity measurements in fission.