Isospin fractionation in the nucleon emissions and fragment emissions in the intermediate energy heavy ion collisions
Abstract The degree of isospin fractionation is measured by ( N / Z ) n /( N / Z ) N imf , where ( N / Z ) n and ( N / Z ) N imf are the saturated neutron–proton ratio of nucleon emissions (gas phase) and that of fragment emissions (liquid phase) in heavy ion collision at intermediate energy. The calculated results by using the isospin-dependent quantum molecular dynamics model show that the degree of isospin fractionation is sensitive to the neutron–proton ratio of colliding system but insensitive to the difference between the neutron–proton ratio of target and that of projectile. In particular, the degree of isospin fractionation sensitively depends on the symmetry potential. However, its dependences on the isospin dependent in-medium nucleon–nucleon cross section and momentum dependent interaction are rather weak. The nucleon emission (gas phase) mainly determines the dynamical behavior of the degree of isospin fractionation in the isospin fractionation process, compared to the effect of fragment emission. In this case, we propose that ( N / Z ) n /( N / Z ) N imf or ( N / Z ) n can be directly compared with the experimental data so that the information about symmetry potential can be obtained.
Determining the Density Dependence of the Nuclear Symmetry Energy Using Heavy-Ion Reactions
We review recent progress in the determination of the subsaturation density behavior of the nuclear symmetry energy from heavy-ion collisions as well as the theoretical progress in probing the high density behavior of the symmetry energy in heavy-ion reactions induced by high energy radioactive beams. We further discuss the implications of these results for the nuclear effective interactions and the neutron skin thickness of heavy nuclei.
Strategies for glass based photonic system integration
There is a clear tendency to integrate more and more opto-electronic and micro-optical components like optical fibers, laser diodes, modulators, isolators, beam-splitting components and micro lenses in also increasingly dense and complex assemblies. The paper will discuss thin glass as a very promising base material for that kind of photonic packaging on interposer and board level including optical interconnection using fibers.