Very long optical path-length from a compact multi-pass cell

The multiple-pass optical cell is an important tool for laser absorption spectroscopy and its many applications. For most practical applications, such as trace-gas detection, a compact and robust design is essential. Here we report an investigation into a multi-pass cell design based on a pair of cylindrical mirrors, with a particular focus on achieving very long optical paths. We demonstrate a path-length of 50.31 m in a cell with 40 mm diameter mirrors spaced 88.9 mm apart - a 3-fold increase over the previously reported longest path-length obtained with this type of cell configuration. We characterize the mechanical stability of the cell and describe the practical conditions necessary to achieve very long path-lengths

On the influence of electron-beam parameters on TWT small-signal gain

The electron beam is one of the main components in traveling-wave tubes (TWTs). A study on the influence of the parameters related to the electron beam on small-signal gain of TWTs is proposed. In particular, the effect of the variations of electron-beam voltage, the perveance of the electron gun, and electron beam radius are investigated. A five-section TWT was considered in the study. (C) 2002 Wiley Periodicals, Inc

On predicting the results of applying workflow management in a healthcare context

Even though workflow management systems are currently not being applied on a wide scale in healthcare settings, their benefits with respect to operational efficiency and reducing patient risk seem enticing. The authors show how an approach that is rooted in simulation can be useful to predict the benefits of using a workflow management system. The approach is discussed and its application is demonstrated in the setting of the pre-operative process as being executed in the Bronovo hospital. The approach is considered useful for other healthcare organizations in search for a better foundation for the application of workflow technology