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.
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
135204416
Searching for new green wavelength shifters in polystyrene
A series of commercially available fluorescent compounds was tested as wavelength shifters in polystyrene for the tile/fiber SDC calorimeter. The objective was to find a green-fluorescing compound with short decay time (3--7 ns). Transmittance, fluorescence, and decay time measurements were performed in order to characterize each compound in polystyrene. These samples were also studies for radiation-induced damage.
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.
121030648
Systematic study of reaction functions of weakly bound nuclei
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.
119585509
Systematic analysis of the effect of a positive Q-value neutron transfer in fusion reactions
93131241
The parametrization of Coulomb barrier heights and positions using the double folding model
Abstract The Coulomb barrier heights and positions are systematically shown with mass numbers and charge radii of the interacting nuclei. The nuclear potential is calculated by using the double folding model with the density-dependence nucleon–nucleon interaction (CDM3Y6). The pocket formulas are obtained for the Coulomb barrier heights and positions by analyzing several hundreds of heavy-ion systems with mass numbers from light nuclei to heavy nuclei. The parameterized formulas can reproduce the calculated barrier heights and positions by using the double folding model within the accuracy of ±1%. Moreover, the results are agreeable with the experimental data. The relation between the barrier height and the barrier position is also studied.