Diode laser absorption spectroscopy for process control: Sensor system design methodology
A laser absorption spectroscopy (LAS) system has been developed at Lawrence Livermore National Laboratory (LLNL) for process control. LAS has proven itself to be an accurate and reliable method to monitor both density and composition. In this paper the important features and components of an industrial LAS diagnostic are described. Application of this approach to vaporization processes requires careful selection of the species and transitions to be monitored The relative vapor pressure, hyperfine structure, isotopic frequency shifts, and electronic temperature all effect the selection of a particular transition. In this paper we describe the methodology for choosing the optimal transition or transitions. Coevaporation of a titanium-niobium alloy is used to illustrate the methodology. In a related paper, T.M. Anklam et al describe the application of this diagnostic to monitoring and controlling composition in a physical vapor deposition process of industrial interest.
- Research Organization:
- Lawrence Livermore National Lab., CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States); Department of Defense, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 80398
- Report Number(s):
- UCRL-JC--118757; CONF-950454--1; ON: DE95011801
- Country of Publication:
- United States
- Language:
- English
Similar Records
Evaporation monitoring and composition control of alloy systems with widely differing vapor pressures
Evaporation monitoring and composition control of alloy systems with widely differing vapor pressures