Muon induced quadrupole photofission

The probability of non-radiative decay of the 3d level in muonic 237Np

“…Assuming most of the radiationless 3d--, ls transition probability to give rise to prompt neutron events, as in the case in 238U [ 7 ], one may conclude that the radiationless 2p-, I s transition plays a much more important role for prompt fission in 237Np than is in the case in 238U. This has, however, to be verified in a separate fission-X-ray coincidence experiment.…”

“…Regarding prompt fission of muonic 238U, about 75% of all events are due to the 3d-, 1 s radiationless transition [7 ]. The question then arises how the yield of prompt fission is shared between the 3d-, ls and the 2p~ ls radiationless transitions in muonic 237Np, where the total prompt fission rate per stopped ~t-is about 10 times higher than the corresponding figure for 2380.…”

“…The role of quadrupole 3d~ Is radiationless transitions in nuclear excitation, leading to prompt processes like T decay, neutron emission or fission [1][2][3][4] has been discussed in several papers [5][6][7][8].…”

“…In order to clarify these points, we performed a measurement on 237Np tO determine the probability of the radiationless muonic 3d~ ls transition, using the same experimental method as was used to determine the non-radiative decay of the 3d level in muonic 238U [6,7].…”

The probability of prompt and delayed fission of muonic237Np

“…(2p-~ ls)-and (3d--,ls)-transitions in several muonic actinide nuclei, and of their respective fission probabilities. The energies of the barriers of fissile actinides are comparable to the energies of the muonic K s X-rays, while the fissility varies strongly from Th to Pu [5,[9][10][11]. Experimentally, there is a systematic and rapid increase of the probability of prompt fission with the value of the fissility parameter [9][10][11].…”