Among the various micro-powers being investigated, betavoltaic batteries are very attractive for numerous applications because of their advantages of high energy density, long life, strong anti-interference, and so on. Based on the basic principle of the betavoltaic effect, the current paper adopted the Monte Carlo N-Particle code to simulate the transport processes of β particles in semiconductor materials and to establish the calculation formulas for nuclear radiation-generated current, open circuit voltage, and so on. By discussing the effect of minority carrier diffusion length, doping concentration, and junction depth on the property of batteries, the present work concluded that the best parameters for batteries are the use of silicon and the radioisotope Ni-63, i.e., Ni-63 with a mass thickness of 1 mg/cm2, Na=1×1019 cm-3, Nd=3.16×1016 cm-3, junction area of 1 cm2, junction depth of 0.3 μm, and so on. Under these parameters the short-circuit current, open circuit voltage, output power, and conversion efficiency are 573.3 nA, 0.253 V, 99.85 nW, and 4.94%, respectively. Such parameters are valuable for micro-power fields, such as micro-electromechanical systems and pacemakers, among others.
Betavoltaic radioisotope microbatteries have gradually become the research direction of micro-power sources because of their several advantages,including small scale,stable output performance,long service life,high energy density,strong anti-jamming capability,and so on.Based on the theory of semiconductor physics,the current paper presented a design scheme of isotope microbattery with wide-gap semiconductor material GaN and isotope 147Pm.In consideration of the isotope's self-absorption effect,the current paper studied and analyzed the optimization thickness of semiconductor and isotope source,junction depth,depletion region thickness,doping concentration,and the generation and collection of electron hole pairs with simulation of transport process of beta particles in semiconductor material using Monte Carlo simulation program MCNP.In the proposed design scheme,for a single decay,an average energy of 28.2 keV was deposited in the GaN,and the short circuit current density,open circuit voltage,and efficiency of a single device were 1.636 μA/cm2,3.16 V,and 13.4%,respectively.
作为获国际认可的第四代核电站反应堆堆型之一的熔盐堆(Molten salt reactor,MSR),具有固有安全性高、经济性好、核资源可持续发展以及易于防止核扩散等优点。针对石墨-熔盐零功率堆的几何参数,利用蒙特卡罗计算程序MCNP5建立了物理计算模型,计算临界情况下堆芯径向、轴向中子通量及增殖区厚度与Th-U转换比(Conversion ratio,CR)的关系。结果表明,(1)石墨-熔盐零功率堆堆芯中子通量密度分布较为平坦;(2)石墨-熔盐零功率堆反射层厚度和增殖区厚度在一定范围内,CR随反射层厚度或增殖区厚度的增加而增加,当超出该范围,CR不再随反射层厚度或增殖区厚度的增加而明显增加。
