125042076
Comparative studies of Coulomb barrier heights for nuclear models applied to sub-barrier fusion
120119782
Calculation of half-lives of cluster decay by using proximity potential with a new universal function
Abstract The half-lives of cluster decays are calculated using proximity potential model with a new universal function, and compared to the experimentally measured values and the theoretical ones of liquid drop model. The results of the present calculations show reasonable agreement with the experimental data as well as the half-life calculations of liquid drop model. In the present work, it is certified that proximity potential model with the new universal function can be used successfully to calculate the half-lives of cluster decays for heavy nuclei.
121030648
Systematic study of reaction functions of weakly bound nuclei
120110625
Study of the universal function of nuclear proximity potential between α and nuclei from density-dependent nucleon-nucleon interaction
The universal function of proximity potential between α and nuclei is systematically studied from the double-folding model with the density-dependent nucleon-nucleon interaction (CDM3Y6) by analyzing different target nuclei with Z = 48–92. The analytical formula of universal function is obtained at s0 > −1 by fitting all of the calculated values. Using this formula we calculate the half-lives of α decay for heavy nuclei in comparison with the values of the experimental data. It is shown that the half-lives of the α decay calculated from the presently obtained universal function in proximity potential can keep within a factor of 3 with the experimental data.
120893139
Calculation of {alpha} preformation for nuclei near N=162 and N=184
The {alpha} preformation factor and the penetration probability are carefully analyzed for heavy and superheavy even-even nuclei. The penetration probability of an {alpha} cluster in the parent nucleus is calculated within the WKB approximation, whereas the nuclear potential between an {alpha} cluster and the daughter nucleus is obtained in the frame of a double-folding model with a density-dependent nucleon-nucleon interaction, in which the zero-range exchange term is supplemented. The {alpha} preformation factors in different shell regions are compared. It is shown that shell effects play an important role in {alpha} preformation. The preformation factor can supply information on the nuclear structure, and the penetration probability mainly determines the {alpha}-decay half-life. The results indicate that the deformed-subshell region at N=162 is different from that at N=152, and Z=114 and N=184 may lie in the closed-shell region.
55019383
Gamma-irradiation of coumarins in a polystyrene matrix
Abstract Polystyrene samples doped with commercially available coumarin derivatives were prepared and tested as wavelength shifters for plastic scintillation applications. Radiation damage studies were performed utilizing a 60 Co source. Transmittance and light yield measurements were recorded before and after irradiation (100 kGy), and after annealing of the samples. All samples experienced losses in transmittance and light yield as a result of radiation-induced damage to the polymer and in some cases, the dopant. None of the coumarins examined in this study outperformed the commonly-used green wavelength shifter, K-27, after irradiation.
119182289
Single spin asymmetry in lepton angular distribution of Drell-Yan processes
A bstractWe study the single spin asymmetry in the lepton angular distribution of Drell-Yan processes in the framework of collinear factorization. The asymmetry has been studied in the past and different results have been obtained. In our study we take an approach different than that used in the existing study. We explicitly calculate the transverse-spin dependent part of the differential cross-section with suitable parton states. Because the spin is transverse, one has to take multi-parton states for the purpose. Our result agrees with one of the existing results. A possible reason for the disagreement with others is discussed.
135661547
Summary of the radiation damage studies of the SDC dopants in polystyrene
Approximately 80 commercially available fluorescent organic compounds were studied as dopants in a polystyrene matrix for possible use in wavelength shifting (WLS) fibers. The goal was to find a new green- emitting WLS fiber which would outperform in light yield and decay time the currently available fiber doped with K-27. Therefore the fluorescent compounds of interest should exhibit the following spectroscopic characteristics in polystyrene: {lambda}{sub abs} = 400--450 nm,{lambda}{sub em} = 450--550 nm, {tau} = 3--7 ns and quantum efficiency of minimum 0.7. Polystyrene samples doped with different fluorescent compounds were prepared and characterized. Of all the compounds tested, only a series of coumarins exhibited the spectroscopic characteristics of interest. Radiation damage studies had to be performed on these samples in order to condusively determine if they were better candidates than K-27 for green WLS fibers. AU samples except those showing opacity or deep coloration were irradiated. They were, however, separated in two sets. Radiation damage set No. 20 was mainly formed by the coumarin derivatives. Radiation damage set No. 22 was based on the remaining samples. The irradiations were performed at the Phoenix Memorial Laboratory using a {sup 60}Co source. Both sets were exposed to a total dose ofmore » 10 Mrad in air, at a dose rate of 1.8 Mrad/h. Transmittance measurements were recorded before and after irradiation, and after annealing. After irradiation, the samples were annealed in oxygen to accelerate the recovery process.« less
121346859
Study of the halo nucleus 6He through the direct nuclear reactions
Differential cross sections for quasi-elastic scattering, breakup reaction as well as 1n- and 2n-transfer reactions induced by 6He at 25 MeV/nucleon from a 9Be target are reported. The experimental data were analysed in the context of the coupled-channel calculations. The internal structure of 6He is discussed and further studies are proposed.
121554245
Coumarins as wavelength shifters in polystyrene
Abstract A series of commercially available coumarins was tested as wavelength shifters in polystyrene for a tile/fiber calorimeter application. The objective was to find a compound that when incorporated in a polystyrene matrix absorbed in the 400–450 nm wavelength range, fluoresced in the green region of the visible spectrum ( λ em = 450−550 nm), and exhibited both short decay time and high quantum yield. Transmittance, fluorescence, and decay time determinations were performed in order to characterize each coumarin in polystyrene. Two coumarins (C510 and C515) were found to have faster decay times (∼8 ns vs. 12 ns) and superior light output (100–120%) compared to the commonly-used green wavelength shifter, K-27.