激光驱动氘-氘锂包层氚增殖试验中的中子源保真度
Neutron-source fidelity for laser-driven D--D lithium-blanket tritium-breeding tests
AI总结：
研究激光驱动D-D锂包层氚增殖试验中的中子源保真度问题，通过耦合粒子模拟、源模型和中子输运方法，分析不同锂情况下的氚产量变化及源模型影响，量化了相关效应。
AI中文摘要：
紧凑型氘-氘（D-D）中子源可为锂包层研究提供可控辐照场，但其能量和角度分布与传统的2.45 MeV各向同性表示不同。我们将靶法向鞘层加速氘核的粒子模拟与厚靶D(d,n)^3He源模型及蒙特卡罗中子输运相结合。对于天然锂，七个二维源使每个源中子的氚产量相对于理想源变化-2.5%至+54.1%。匹配的三维计算使产量增加43.5%，并将相应比例从1.5406降至1.4350。源替代表明差异主要是光谱性的。真实光谱使^6Li贡献降低6.9%，但可及的^7Li(n,Xt)响应超过了这一损失。富集到90%的^6Li使总变化保持在±1.5%以内。在匹配的三维转换器和包层计算中，直接D(d,p)T产量为每个源中子0.8458个氚核，分别占天然锂和富集锂联合产量的98.1%和86.9%。高密度聚乙烯慢化使氚产量提高约一个数量级，但先减弱然后逆转了包层氚产量的增加。该分析量化了紧凑型增殖试验中源模型的影响。
英文摘要：
Compact deuterium--deuterium (D--D) neutron sources can provide controllable irradiation fields for lithium-blanket studies, although their broad joint energy and angle distributions differ from the conventional $2.45$~MeV isotropic representation. We couple particle-in-cell (PIC) simulations of target-normal-sheath-accelerated deuterons with a thick-target $D(d,n)^{3}$He source model and Monte Carlo neutron transport. For natural lithium, the seven two-dimensional sources change tritium production per source neutron by $-2.5\%$ to $+54.1\%$ relative to the ideal source. The matched three-dimensional calculation gives an increase of $43.5\%$ and lowers the corresponding ratio from $1.5406$ to $1.4350$. Source substitutions show that the difference is predominantly spectral, since the real spectrum alone gives a factor of $1.4199$, while using the real neutron emission directions in place of isotropic emission adds only a further factor of $1.0106$ in the three-dimensional case. The real spectrum lowers the $^{6}$Li contribution by $6.9\%$, but the accessible $^{7}$Li$(n,Xt)$ response exceeds this loss. Enrichment to $90\%$ $^{6}$Li keeps the total change within $\pm1.5\%$. In the matched three-dimensional converter and blanket calculation, direct $D(d,p)$T production is $0.8458$ tritons per source neutron and accounts for $98.1\%$ and $86.9\%$ of the combined production for natural and enriched lithium, respectively. High-density polyethylene moderation raises tritium production by about one order of magnitude but first weakens and then reverses the increase in blanket tritium production. The analysis quantifies source-model effects in compact breeding tests.
