The high-uniformity tube furnace facility provides the ideal environment for quantitative measurements of absorption spectra and spectral parameters (line strength, line-broadening coefficients, etc.). It is also provides controlled conditions for sensor validations.
The facility consists of an MHI Inc., 15 kW furnace with three PID-controlled zones. It is capable of providing uniform temperatures of +/- 2 K over the length of the furnace at temperatures up to 1600 K. A stainless steel gas delivery manifold is located above the furnace which interconnects two Baratron pressure gauges (100 torr, 10000 torr), a Setra pressure gauge (1000 psi), and vacuum, purge, and test gas lines.
Two static optical cells have been constructed for use in the furnace. A quartz optical cell with a 76 cm pathlength can be used for low pressure (<1 atm) measurements of various spectral parameters (line strength, line-broadening, pressure-induced shift coefficients, and their temperature dependences). The figure above shows example absorption scans at two different pressures and indicates some of the spectral parameters that can be inferred from these scans.
A high-pressure optical cell with a 37 cm pathlength has also been developed. It is capable of pressures to 50 atm and temperatures to 1050 K.
The figure above shows an endview of the cell at 1050 K and 50 atm from outside the tube furnace.
Using this cell, measurements of high-pressure absorption spectra can be obtained to verify spectral parameters and test theoretical line shape models. It can also be used to validate high-pressure sensors. The figure above shows the validation of a sensor used for thermometry in IC engines.