High-Z electron screening: the cases 50V(p,n)50Cr and 176Lu(p,n)176Hf
High-Z electron screening: the cases 50V(p,n)50Cr and 176Lu(p,n)176Hf
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DOI：
10.1088/0954-3899/32/4/007
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发表时间：
2006-04
期刊：
影响因子：
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通讯作者：
K. Kettner;H. W. Becker;F. Strieder;C. Rolfs
中科院分区：
文献类型：
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作者：
K. Kettner;H. W. Becker;F. Strieder;C. Rolfs
研究了在Ep = 0.75 ~ 1.55 MeV条件下，VO2绝缘体、V金属和PdV10%合金在50V(p,n)50Cr中的电子屏蔽性能。相对于绝缘子，我们发现金属和合金的屏蔽能量UD分别为27±9和34±11 keV。我们还研究了Lu2O3绝缘体、Lu金属和PdLu10%合金中质子能相似的176Lu(p,n)176Hf；在Epr = 0.81 MeV处，我们观察到金属和合金的窄共振，表现出明显的刘易斯峰，质子共振能相对于绝缘体的位移分别为UD = 32±2和33±2 keV。数据表明，电子筛选发生在整个元素周期表上，并不局限于迄今所研究的轻核素之间的反应。在出口通道中有中子的两个反应进一步证明了电子屏蔽是在反应的入口通道中产生的效应，而不受出口通道的抛射物的影响，即不受目前研究的出口通道的带电粒子的影响。这些UD值可以用deye的等离子体模型来解释，该模型适用于金属样品中的准自由电子。这些数据与先前对金属中d+d、Li+p和Be+p聚变反应的研究一起验证了Debye模型的预测，即UD与目标原子的核电荷量成比例。最后，我们讨论了金属中超铀废物α-衰变率提高的可能性。
The electron screening in 50V(p,n)50Cr has been studied at Ep = 0.75 to 1.55 MeV for different environments: VO2 insulator, V metal and PdV10% alloy. Relative to the insulator we find for the metal and alloy a large screening energy UD = 27 ± 9 and 34 ± 11 keV, respectively. We also studied 176Lu(p,n)176Hf at similar proton energies for a Lu2O3 insulator, a Lu metal and a PdLu10% alloy; here we observed a narrow resonance at Epr = 0.81 MeV exhibiting a prominent Lewis peak and a shift in proton resonance energy of UD = 32 ± 2 and 33 ± 2 keV for the metal and alloy, respectively, relative to the insulator. The data demonstrate that the electron screening occurs across the periodic table and is not restricted to reactions among light nuclides studied so far. The two reactions with neutrons in the exit channel demonstrate furthermore that the electron screening is an effect in the entrance channel of the reaction and is not influenced by the ejectiles of the exit channel, i.e. by the charged particles of the exit channel studied so far. The UD values can be explained by the plasma model of Debye applied to the quasi-free electrons in the metallic samples. The data together with previous studies of the fusion reactions d+d, Li+p and Be+p in metals verify the Debye model prediction, i.e. a scaling of UD with the nuclear charge of the target atoms. Finally, we discuss the possibility for an enhanced α-decay rate of transuranic waste in metals.