Apparatus of Uranium Atomic bbam by Laser Heating for Laser Isotope Separation

激光同位素分离是成本有效的，因为原则上，一个同位素原子可以由一个激光光子分离。激光同位素分离的总效率取决于激光效率和产生原子蒸气束的炉效率。由于电子束加热效率低，发展一种新的蒸发金属靶产生原子束的方法具有很大的希望。发展了激光加热技术，研究了原子束特性。实验结果总结如下：1.激光产生的原子束的空间分布服从cos^5rheta定律，在垂直于靶面的方向上获得了小发散角的原子束.原子蒸气的量与吸收的激光能量密度成正比。吸收系数取决于激光波长.激光加热的原子蒸气包括10%的离子。离子的能量分布服从Mawellian分布.产生原子蒸气所需的激光能量为1x 10 ^<-15>J/原子，这与电子束加热相当。通过一维热输运计算，分析了激光加热靶内的温度分布。为了提高蒸发效率，重要的是减少具有多余能量的原子蒸气的分数。

Laser isotope separation is cost effective since, in principle, one isotopic atom can be separated by one laser photons. Total efficiency of the laser isotope separation is dependent on the laser efficiency and the oven efficiency to produce atomic vapor beam. It is greatly expected to develop a new method to evaporate the metallic target and to produce the atomic beam instead of electron-beam heating because of its low efficiency. Here laser heating technique has been developed and the atomic beam characteristics have been investigated. The experimental results are summarized as follows :1. Spatial distributions of the laser produced atomic beam obeys cos^5rheta law and the atomic beam with small divergence is obtained perpendicularly to the target surface.2. Amount of atomic vapor is proportional to the absorbed laser energy density. Absorption coefficient depends on the laser wavelength.3. The laser heated atomic vapor includes 10% of ions. The energy distribution of ions is Mawellian.4. The laser energy required to produce atomic vapor is 1x10^<-15>J/atom, which is comparable to electron-beam heating.5. Temperature distribution in the laser heated target was analyzed by one-dimensional heat transport calculation. In order to improve the vaporization efficiency, it is important to reduce the fraction of atomic vapor with excess energy.