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.
Influence of different binding energies in clusterization approach: fragmentation as an example
We study multifragmentation within the framework of a quantum molecular dynamics model using different binding energy formulae in the secondary algorithm; namely, the minimum spanning tree approach. A comparison of theoretical results with experimental data over a wide range of energy, mass and impact parameter is also presented. Our detailed analysis shows an insignificant difference of different binding energies when used at finite temperatures on the fragmentation pattern which, on the other hand, becomes significant when used for cold matter.
Parameters for low energy operation of CESR
We present a detailed design for operation of the Cornell Electron Storage Ring, CESR, in the energy range covering the /spl psi/ resonances and the Charm and Tau thresholds, as well as reaching to the upper Y resonances near 11 GeV. The addition of 18 m of super-ferric wiggler magnets will partially restore low energy beam emittance and damping times. Installation of superconducting quadrupoles in the interaction region and the addition of high performance superconducting RF cavities will enhance performance at all energies. Studies of optics, beam dynamics, wiggler and vacuum system performance, beam stability, and beam-beam effects confirm operation with a luminosity of 3/spl times/ 10/sup 32/ CM/sup -2/ sec/sup -1/ at 1.88 GeV.