Multifragmentation threshold in 93 Nb + nat Mg collisions at 30 MeV/nucleon
We analyzed the $^{93}Nb$ on $^{nat}Mg$ reaction at $30$ MeV/nucleon in the aim of disentangling binary sequential decay and multifragmentation decay close to the energy threshold, i.e. $\simeq 3$ MeV/nucleon. Using the backtracing technique applied to the statistical models GEMINI and SMM we reconstruct simulated charge, mass and excitation energy distributions and compare them to the experimental ones. We show that data are better described by SMM than by GEMINI in agreement with the fact that multifragmentation is responsible for fragment production at excitation energies around $3$ MeV/nucleon.
Improved method for the determination of neutron energies from their times-of-flight
Abstract The kinetic energy of a neutron is determined experimentally by measuring its time-of-flight and flight distance from the source to the detector. However, this determination is vitiated by errors since the exact location of the interaction of the neutron within the detector is unknown. Moreover, more than one interaction may be necessary for the deposited energy to reach the detector threshold. We compare the different existing energy determination methods and introduce the method which gives the minimum-variance unbiased estimator of the neutron energy. The method is based of the inversion of the detector response function, for which we propose a universal algorithm. It is shown that the precision of the new method does not deteriorate with the length of the detector, which opens the possibility of conceiving detectors with a higher efficiency.
Influence of nucleon Fermi motion on incomplete fusion
Abstract Velocity spectra were measured for evaporation residues produced in fusion reactions induced by 5–35 MeV/ A 14 N. The results, together with published data for 16 O and 20 Ne induced fusion, are shown to reveal a projectile dependence of incomplete fusion processes. The data can be qualitatively described in terms of a picture which takes into account the vector addition of the center-of-mass velocities of the interacting nuclei with the intrinsic Fermi velocities of the nucleons.