Study On Deuteron Density And Its Effect On Deducing Of Screening Potential From D(d,p)T Reaction In Metal

A lasting topic in nuclear astrophysics is the screening of the nuclear Coulomb potential due to the atomic electrons in laboratory nuclear physics experiments which enhances the experimental reaction cross-sections at low energies relative to the bare nucleus. The cross sections of nuclear fusion reactionσ(E) in energy region far below the Coulomb barrier is roughly represented by the Gamow fac-tor, and drops exponentially with decreasing projectile energy, which are hard to be measured accurately and are extrapolated from the data at higher energies customarily. The Coulomb potential of the target nucleus and projectile theoret-ically calculated from bare nuclei states. However, the target nuclei studied in laboratory are usually in the form of atoms or molecules, so that the Coulomb barrier is effectively reduced both in height and radial extension. As a result, the corresponding cross sections are higher than would be the case for bare nuclei. The enhanced cross sectionσs(E) is expressed asσs(E)=σb(E+Ue) with an electron screening potential Ue, andσb(E) is the cross section for bare nucleus.The D(d,p)T reactions in different materials in sub-low energy region have been studied. Though analysis methods for the Ue of D(d,p)T reaction in metal environment were different, they were all based on an assumption of a stable and homogeneous deuteron density distribution. However, the deuteron atom is smaller than any metal atoms and its utmost high mobility makes the assump-tion doubtful. Therefore, one can suppose neither a stable nor a homogeneous deuteron density distribution which is required by the standard analysis method. So a rough model of deuterons density distribution is introduced.The experiment was performed at the Laboratory of Nuclear Science, To-hoku University. The deuterated thick targets used in this work are Be, Al, Dy, Yb and Zr metal, respectively. The projectile energy range is 5 keV～10 keV(CMS), and the temperature is 121 K,136 K,134 K,163 K and 140 K re-spectively. The screening potential are calculated using the model in different metal, and they are 116±46 eV,156±40 eV,172±36 eV,211±61 eV and 175±53 eV, respectively. The result of the experiment indicate that the D(d,p)T reaction in metal are assuredly enhanced, and the Ue is correlative to the metal material.The experiments of temperature (the thermal input power) effects to the proton yield were performed in Yb and Pd environment. The yield of proton is decreasing with the thermal input power increasing at the same projectile energy. At the same time, it is found that the effective target area shifts at different pro-jectile energy, and the changing range is estimated.In this work, for the first time, the deuteron density is taken as a variable during dealing with the experiment data. However, we would make notes that the simulation of SRIM in the low energy region could introduce considerable error, and the model of deuteron density should be improved and more detailed study for different metals are required.