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

为了研究固体颗粒成核的机制及其在太阳系物质演化中的作用，我们研制了一种模拟简单分子到聚合团簇非平衡均质成核的实验装置。可冷凝气体在分子束中准直并引入高真空室。从另一个真空口提供的受控环境气体脉冲束穿过先前的分子束。该方法在腔室的局部区域内满足了团簇形成的必要条件，并满足了成核和凝结的定量分析。在这个为期三年的资助项目中，我们取得了以下成果：(1)我们建立了一个能够在清洁环境下形成簇的系统。安装了一个无振动的超高真空系统。(2)我们改进了一种高真空高温气体射流装置，从高温气体混合物中截断毫秒级的小脉冲。该装置的试验结果令人满意。(3)研制了TOF质谱仪，用于对多次碰撞形成的聚合团簇进行原位分析。(4)为了提高用平成8资助购买的准分子激光装置的发射度，我们使用高透射的焦透镜获得了必要的局部能量通量。(5)根据上述发展，我们进行了非平衡均形核的实验室实验。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数量太少而无法检测到。为了完成这一任务，需要更高的激光能量通量和更大的可冷凝气体的质量通量。

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..