Planar and textured surface optimization for a tritium‐based betavoltaic nuclear battery
Planar and textured surface optimization for a tritium‐based betavoltaic nuclear battery
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DOI：
10.1002/er.4563
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发表时间：
2019-05
影响因子：
4.6
通讯作者：
J. Russo;M. Litz;I.I. William Ray;Hakan Berk;Hansol Cho;D. Bigio;A. Weltz;T. Alam
中科院分区：
文献类型：
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作者：
J. Russo;M. Litz;I.I. William Ray;Hakan Berk;Hansol Cho;D. Bigio;A. Weltz;T. Alam
远程、地面和太空传感器需要具有足够高功率和能量密度的源，以连续运行数十年。传统化学源的能量密度较低，使用寿命为 10 至 15 年，具体取决于环境条件。使用 β 发射放射性同位素的贝塔伏 (βV) 核电池的能量密度比传统化学能源高约 1000 倍。它们在给定体积中的电功率密度（Pe，vol，W/cm3）是β-通量表面功率密度Pβ-、放射性同位素和换能器之间的表面界面类型、β-范围以及换能器厚度和转换效率（ηs）的函数。氚是最可行的β发射放射性同位素，因为它具有商业可用性、低生物毒性、半衰期和低能量，可最大限度地减少穿透深度和换能器的损坏。为了最大化 Pe,vol，βV 核电池中必须使用固体或液体形式的氚。开发了使用 MCNP6 的蒙特卡罗源模型，以最大化氚基 βV 核电池的 Pe,vol。首先，对不同氚化物（即氚化钛和氚化氮氧化物）的平面耦合结构和厚度为 1 和 100 μm 的半导体换能器 (4H-SiC) 进行建模。结果表明，β源效率（ηβ），即沉积在换能器中的能量百分比，随着氚化合物质量密度的增加而降低。最高 Pe,vol 取决于多种特性的组合：比活度（Am，以 Ci/g 为单位）、质量密度和 4H-SiC 层厚度。具有最高 Am 2372 Ci/g 的氚化硝基氧产生最高 Pe,vol 2.46 mW/cm3。其次，对 3D 耦合配置进行建模，以增加放射性同位素源和纹理换能器表面之间的表面界面。 3-D 耦合配置增加了沉积到传感器中的能量百分比，因为相同体积的传感器和源之间有更多的表面接口。选择氚化氮氧化物作为放射性同位素源，并结合五种不同的纹理表面特征类型。 Pe,vol 作为纹理表面特征和间隙（放射性同位素所在位置）的函数，计算了 1 和 100 μm 4H-SiC 层厚度的宽度。结果表明，除矩形柱阵列外，与平面耦合配置相比，ηβ 有所增加（即，与圆柱孔阵列的平面相比增加约 56.2%）。尽管如此，矩形柱阵列产生了最高的 Pe,vol，为 4.54 mW/cm3，与平面耦合配置相比，增加了 2.29 倍。
Remote, terrestrial, and space sensors require sources that have high enough power and energy densities for continuous operation for multiple decades. Conventional chemical sources have lower energy densities and lifetimes of 10 to 15 years depending on environmental conditions. Betavoltaic (βV) nuclear batteries using β‐‐emitting radioisotopes possess energy densities approximately 1000 times greater than conventional chemical sources. Their electrical power density (Pe,vol in W/cm3) in a given volume is a function of β‐‐flux surface power density Pβ− , surface interface type between radioisotope and transducer, β‐ range, and transducer thickness and conversion efficiency (ηs). Tritium is the most viable β‐‐emitting radioisotope because of its commercial availability, low biotoxicity, half‐life, and low energy, which minimizes the penetration depth and damage of transducer. To maximize Pe,vol, tritium in solid or liquid form must be used in the βV nuclear battery. A Monte Carlo source model using MCNP6 was developed to maximize the Pe,vol of a tritium‐based βV nuclear battery. First, a planar coupling configuration with different tritiated compounds (ie, titanium tritide and tritiated nitroxide) and a semiconductor transducer (4H‐SiC) with thicknesses of 1 and 100 μm were modeled. The results showed that β‐‐source efficiency (ηβ), which is the percentage of energy deposited in the transducer, decreased as the tritiated compound's mass density increased. The highest Pe,vol was dependent on a combination of characteristics: specific activity (Am in Ci/g), mass density, and 4H‐SiC layer thickness. The tritiated nitroxide with the highest Am at 2372 Ci/g produced the highest Pe,vol at 2.46 mW/cm3. Second, a 3‐D coupling configuration was modelled to increase surface interfacing between the radioisotope source and textured transducer surface. 3‐D coupling configuration increased the percentage of energy deposited into the transducer because of more surface interfacing between the transducer and source in the same volume. The tritiated nitroxide was selected as the radioisotope source coupled with five different textured surface feature types. The Pe,vol as a function of textured surface feature and gap, where the radioisotope is located, width was calculated for 1‐ and 100‐μm 4H‐SiC layer thicknesses. Results showed that ηβ increased compared with planar coupling configuration (ie, approximately 56.2% increase over planar with cylindrical hole array) except with the rectangular pillar array. Still, the rectangular pillar array produced the highest Pe,vol at 4.54 mW/cm3 with an increasing factor of 2.29 compared with the planar coupling configuration.