Laboratory surface astrophysics experiment
Laboratory surface astrophysics experiment
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实验室表面天体物理实验
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
M. McCoustra
中科院分区：
文献类型：
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作者：
H. Fraser;M. Collings;M. McCoustra
在这篇文章中，我们描述了一个实验室天体物理学实验的设计和建设，重现了星际介质（ISM）的恶劣条件，并用于研究那里发生的非均相化学。诺丁汉表面天体物理学实验是用来确定，经验，准确，通常是第一次，关键的物理和化学常数是至关重要的建模和理解ISM。它被专门设计用于研究星际条件下的气固相互作用。在原恒星或原行星区域的尘埃盘中，压力制度与分子密度理想匹配。在常规情况下，双极真空系统能够获得的压力仅比ISM中的压力高出三个数量级，在这些区域中，H2和CO这两种最丰富的气体的相对浓度相似，并且不存在任何其他主要气体组分。一个简短的介绍描述了这个实验背后的天文学动机。节中然后，我们详细介绍了实验中每个组成部分的设计、构造和校准。低温恒温器系统远远超出了设计预期，并达到7至500 K之间的温度。这与ISM相当，在ISM中观察到的尘埃温度为10 K。视线质谱法，反射吸收红外光谱法，石英晶体微量天平质量测量首次结合到一个单一的仪器。该仪器经过仔细校准，并开发了其控制和数据采集系统，以确保尽可能准确地记录实验参数。节中III，我们提出了一些实验结果，从这个系统还没有在其他地方发表。结果表明，该系统可用于确定ISM中常见的各种气体和冰之间的脱附率、ΔdesH、成键系统和粘附概率。该仪器将极大地促进我们对ISM中发生的表面过程的理解，并使我们能够在受控环境中研究“模拟”ISM系统。在这篇文章中，我们说明了实验室表面天体物理学是一个令人兴奋的和新兴的研究领域，特别是这种仪器将通过其对表面科学和天文学的贡献产生重大影响。
In this article we describe the design and construction of a laboratory astrophysics experiment that recreates the harsh conditions of the Interstellar Medium (ISM) and is used to study the heterogeneous chemistry that occurs there. The Nottingham Surface Astrophysics Experiment is used to determine, empirically, accurately, and usually for the first time, key physical and chemical constants that are vital for modeling and understanding the ISM. It has been designed specifically to investigate gas–solid interactions under interstellar conditions. The pressure regime is ideally matched to molecular densities in dusty disks in protostellar or protoplanetary regions. The ultrahigh vacuum system is routinely capable of obtaining pressures that are only three orders of magnitude above those in the ISM, with similar relative concentrations of the two most abundant gases in such regions, H2 and CO, and an absence of any other major gas components. A short introduction describes the astronomical motivation behind this experiment. In Sec. II we then give details of the design, construction, and calibration of each component of the experiment. The cryostat system has far exceeded design expectations, and reaches temperatures between 7 and 500 K. This is comparable with the ISM, where dust temperatures from 10 K have been observed. Line-of-sight mass spectrometry, reflection absorption infrared spectroscopy, and quartz crystal microbalance mass measurements were combined into a single instrument for the first time. The instrument was carefully calibrated, and its control and data acquisition system was developed to ensure that experimental parameters are recorded as accurately as possible. In Sec. III we present some of the experimental results from this system that have not been published elsewhere. The results presented here demonstrate that the system can be used to determine desorption enthalpies, ΔdesH, bonding systems, and sticking probabilities between a variety of gases and ices common to the ISM. This instrument will greatly facilitate our understanding of surface processes that occur in the ISM, and allow us to investigate “mimic” ISM systems in a controlled environment. In this article we illustrate that laboratory surface astrophysics is an exciting and emerging area of research, and this instrument in particular will have a major impact through its contributions to both surface science and astronomy.