High-speed thermo-microscope for imaging thermal desorption phenomena
Matthew E. Staymates, John G. Gillen
In this work, we describe a new imaging system, called a thermo-microscope, that can be used to visualize atmospheric pressure thermal desorption phenomena at high heating rates and frame rates. The system consists of a zoom lens coupled to a high-speed video camera that is focused on the surface of an aluminum nitride heating element. In a typical experiment, the material of interest is rapidly heated beyond its boiling point while the camera captures images at several thousand frames per second. A data acquisition system, along with an embedded thermocouple and infrared pyrometer are used to measure the temperature of the heater surface. We demonstrate that, while a typical thermocouple lacks the response time to accurately measure temperature ramps that approach 150°C per second, it is possible to calibrate the system by using a combination of infrared pyrometry, melting point standards, and a thermocouple. Several examples of high-explosives undergoing rapid thermal desorption are also presented.