The development of a simulation device for the nucleation in the primordial solar nebula.

为了研究固体粒子成核的机制及其在太阳系物质演化中的作用，我们研制了一台模拟从简单分子到聚合团簇的非平衡均匀成核的实验装置。可凝聚气体物种在分子束中准直，并被引入高真空室。从另一个真空端口供应的受控环境气体的脉冲光束穿过先前的分子束。这种方法使团簇形成的必要条件在腔室的局部区域内得到满足，并满足了成核和凝聚的定量分析。在这个为期三年的助学金项目中，我们取得了以下成果：(1)我们已经建立了一个能够在清洁环境中形成星团的系统。我们已经安装了一个无振动的超高真空系统。(2)我们已经改造了一个用于高真空和高温的气体喷射装置，以截断高温气体混合物中数毫秒的小脉冲。装置的测试是令人满意的。(3)我们研制了一台飞行时间质谱仪，用于原位分析由多次碰撞形成的聚合团簇。(4)为了提高平成8助学金购买的准分子激光装置的发射度，我们利用高透射率的焦透镜获得了必要的局域能量通量。(5)在上述发展之后，我们进行了非平衡均匀成核的实验室实验。我们能够观察到低质量范围的团簇，但高质量范围的聚合团簇的丰度太小，无法检测到。为了完成这一任务，需要更高的激光能量通量和来自喷射装置的可凝结气体的更大的质量通量。

In order to investigate the mechanism of the nucleation of solid particles and its role in the evolution of the solar system materials, we have developed an experimental apparatus that simulates the non-equilibrium homogeneous nucleation from simple molecules to polymerized clusters. Condensable gas species are collimated in molecular beams and introduced into a high-vacuum chamber. A pulsed beam of the controlled environmental gas supplied from another vacuum port crosses the previous molecular beams. This method makes the necessary conditions of the cluster formation fulfilled in a localized area of the chamber and suffices the quantitative analysis of the nucleation and condensation. We have obtained the following results during this three-year grant-in-aid project(1) We have built a system that enables the cluster formation in a clean environment A vibration-free ultra-high vacuum system have been installed.(2) We have modified a gas effusion device for high vacuum and high temperature to truncate a mili-second small pulses out of the high-temperature gas mixture. The test of the device was satisfactory.(3) We have developed a TOF mass spectrometer for an in-situ analysis of the polymerized cluster that formed by multiple collisions.(4) In order to improve the emittance from the excimer laser device purchased with a Heisei 8 grant-in-aid, we have obtained a necessary local energy flux with a use of focal lens of high transmission.(5) Following the above developments, we have performed a laboratory experiment of the non-equilibrium homogeneous nucleation. We were able to observe clusters of low mass range, but polymerized clusters of high mass range were too small in abundance to be detected. A higher laser energy flux and a much larger mass flux of the condensable gas from the effusion device will be necessary to accomplish this task..