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Nuclear level density parameter is one of the fundamental quantities required for finding the nuclear level density. The most essential ingredient for the theoretical analysis of nuclear reactions is nuclear level density. This work is a theoretical study on the variation of collective nuclear level density parameter of certain even-even actinides. This calculations were performed by using phenomenological models of level density. The computational code TALYS 1.9 has been made use of for this purpose. Here, we calculated the collective nuclear level density parameter of 268 - 278 Th, 270 - 280 U, 272 - 282 Pu, 274 - 284 Cm, 278 - 288 Cf, 278 - 288 Fm and 280 - 290 No, at neutron separation energy. Variation of collective level density parameter with different mass number is estimated for these selected nuclei. These studies show that nuclear level density parameter is minimum at neutron number N = 180 and 184 for these systems studied. Apart from that, the level density parameters decrease towards N = 184 . [ABSTRACT FROM AUTHOR]

There has been plenty of empirical evidence which shows that the single-particle picture holds to a good approximation in atomic nuclei. In this picture, protons and neutrons move independently inside a mean-field potential generated by an interaction among the nucleons. This leads to the concept of nuclear shells, similar to the electronic shells in atoms. In particular, the magic numbers due to closures of the nucleonic shells, corresponding to noble gases in elements, have been known to play an important role in nuclear physics. Here we propose a periodic table for atomic nuclei, in which the elements are arranged according to the known nucleonic shells. The nuclear periodic table clearly indicates that nuclei in the vicinity of the magic numbers can be understood in terms of a shell closure with one or two additional nucleons or nucleon holes, while nuclei far from the magic numbers are characterized by nuclear deformation. [ABSTRACT FROM AUTHOR]

Evolution of shells has been studied through fluctuations of particle numbers, pairing energies of large number of isotopes and isotones of nuclei evaluated through Skyrme-Hartree-Fock theory after inclusion of optimized tensor interaction. For neutron rich isotopes of Mg, Si, S and Ar no indication of shell closure at N = 28 has been observed. Calculations show occurrence of a doubly shell closed nucleus Fl . [ABSTRACT FROM AUTHOR]

The deformed configurations and rotational band structures in N = 50 Ge and Se nuclei are studied by deformed Hartree-Fock with quadrupole constraint and angular momentum projection. Apart from the 'almost' spherical HF solution, a well-deformed configuration occurs at low excitation. A deformed well-mixed Ω = 1/2 neutron orbit comes down in energy (from the shell above N = 50) to break the N = 50 spherical shell closure. A K = 7 isomer is predicted in Se at fairly low excitation energy. At higher excitation energies (8 MeV), a deformed band with Ω = 7/2- 1/2 (based on h) neutron 1p-1h excitation, for Ge and Se, is shown in our calculation. Our study gives insight into possible deformed structures at spherical shell closure. [ABSTRACT FROM AUTHOR]

The TITAN facility at TRIUMF-ISAC will use four ion traps with the primary goal of determining nuclear masses with high precision, particularly for short lived isotopes with lifetimes down to approximately 10 ms. The design value for the accuracy of the mass measurement is 1 ×10 − 8. The four main components in the facility are an RF cooler/buncher (RFCT) receiving the incoming ion beam, an electron beam ion trap (EBIT) to breed the ions to higher charge states, a cooler Penning trap (CPET) to cool the highly charged ions, and finally the measurement Penning trap (MPET) for the precision mass determination. Additional goals for this system are laser spectroscopy on ions extracted from the RFCT and beta spectroscopy in the EBIT (in Penning trap mode) on ions that are purified using selective buffer gas cooling in the CPET. The physics motivation for the mass measurements are manifold, from unitarity tests of the CKM matrix to nuclear structure very far from the valley of stability, nuclear astrophysics and the study of halo-nuclei. As a first measurement the mass of 11Li will be determined. With a lifetime of 8.7 ms and a demonstrated production rate of 4×104 ions/sec at ISAC the goal for this measurement at TITAN is a relative uncertainty of 5×10 − 8. This would check previous conflicting measurements and provide information for nuclear theory and models. [ABSTRACT FROM AUTHOR]