123311264
Study of the universal function of nuclear proximity potential from density-dependent nucleon–nucleon interaction
Abstract The universal function of proximity potential model is systematically studied from the double folding model with density-dependent nucleon–nucleon interaction (CDM3Y6) by analyzing several hundreds of fusion reaction systems with mass numbers from light nuclei to heavy nuclei. The analytical formula of universal function is obtained at s 0 > − 1 by fitting all of the calculated values. Using this formula we calculate the Coulomb barrier heights for fusion reactions in comparison with the values of the experimental data and Prox77. It is shown that presently obtained universal function in proximity potential model can reproduce the Coulomb barrier heights.
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.
121988940
Analysis of proton radioactivity of nuclei by using proximity potential with a new universal function
Abstract.The nuclear potential between proton and the daughter nuclei is calculated in the frame of the proximity potential with a new universal function. We obtained and analyzed the half-lives of proton radioactivity of the mother nuclei. By comparing to the experimental data and the other calculation results of ground and isomer states of proton emitters, it is found that the present calculation results can reproduce the order of magnitude of the experimental data well. It indicates that the proximity potential with a new universal function can estimate the half-life of proton radioactivity.
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.
121030648
Systematic study of reaction functions of weakly bound nuclei
95842495
The Beijing ISOL initial conceptual design report
Abstract Peking University (PKU) and China Institute of Atomic Energy (CIAE) are jointly proposing to construct a large science facility, temporarily called “Beijing ISOL”. This facility aims at both basic science and application goals, and is based on the double driver system, namely reactor driving and intense deuteron-beam driving. On the basic science side, the radioactive ion beams produced from the isotope separation online (ISOL) device will be used to study the new physics and technologies at the limit of nuclear stability. On the other side regarding to the applications, the facility will be devoted to material research for the nuclear energy system by using typically the intense neutron and ion beams. In the whole process of design, construction and operation, an opening policy will be pursued, and the domestic and international cooperation will be emphasized. Through this project, a joint research and education mode will be established.
118079649
Cross-section measurement and analysis for the Sm-149 (n, alpha) Nd-146 reaction at 6.0 MeV
We have measured the $^{149}\mathrm{Sm}(n,\ensuremath{\alpha})^{146}\mathrm{Nd}$ cross section at 6.0 MeV to be $0.12\ifmmode\pm\else\textpm\fi{}0.018$ mb. This is the first reported result for this cross section in the MeV region and so should be helpful for constraining nuclear data evaluations (which differ by a factor of 40 for this reaction at this energy) and for testing and improving nuclear models. The experiment was performed at the at the 4.5-MV Van de Graaff accelerator of Peking University. Neutrons were produced via the $^{2}\mathrm{H}(d,n)^{3}\mathrm{He}$ reaction using a deuterium gas target, and absolute neutron flux was determined with a small $^{238}\mathrm{U}$ fission chamber. Alpha particles were detected using a two-section gridded ionization chamber in which two large-area $^{149}\mathrm{Sm}{}_{2}{\mathrm{O}}_{3}$ samples were placed back-to-back so that the cross section and forward/backward ratio were measured for nearly the entire 4$\ensuremath{\pi}$ solid angle. The data were compared to statistical-model predictions using the code talys. Good agreement between the measured and theoretical cross sections could be obtained with a small modification of the $\ensuremath{\alpha}$-optical potential parameters from their default values in talys. However, we were not able to reproduce the measured forward/backward ratio. In addition, using the previously reported $^{147}\mathrm{Sm}(n,\ensuremath{\alpha})^{144}\mathrm{Nd}$ cross section at 6.0 MeV together with our new result, good agreement was found between the measured and predicted cross-section ratio for these two isotopes. Finally, none of the existing evaluated data libraries are in agreement with our new data to within the experimental uncertainties.
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
139458138
Final results from the SDC dopant search for new green wavelength shifting (WLS) fibers. Volume 2
This report contains fluorescent spectral graphs of dopant materials for green wavelength shifting fibers.
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.