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Gas behavior in systems at microscale has been receiving significantattention from researchers in the last two decades [1-4]. Today, there is anenhanced emphasis on developing new experimental techniques to capture thelocal temperature profiles in gases at rarefied conditions. The main underlyingreason behind this focus is the interesting physics exhibited by gases at theserarefied conditions, especially in the transition regime. There is the onset oflocal thermodynamic disequilibrium, which manifests as velocity slip andtemperature jump [1-4] at the wall. However, there is limited experimentalevidence on understanding these aforementioned phenomena. With the advances inexperimental facilities, it is today possible, at least in principle, to mapthe local temperature profiles in gases at rarefied conditions. Moleculartagging approach is one such technique which has shown the potential to map thetemperature profile in low pressure conditions [5]. In molecular taggingapproach, a very small percentage of tracer molecules are introduced into thegas of interest, referred as carrier gas. In gas flow studies, the typicaltracers employed are acetone and biacetyl. These tracer molecules, assumed tobe in equilibrium with the carrier gas, are excited with a source of energy ata specific wavelength, typically a laser. The excited molecules are unstableand tend to de-excite in a radiative and non-radiative manner, which ismanifested as fluorescence and phosphorescence. Following the deformation withtime of a tagged line permits to obtain the flow velocity. In addition, thedependence of the phosphorescence and fluorescence intensity to the gastemperature could also allow to use this technique for local temperaturemeasurements. The objective of this study is to develop an experimental setupcapable of simultaneously mapping the wall and fluid near-wall temperatureswith the final goal to measure temperature jump at the wall when rarefiedconditions are reached. The originality of this setup shown in Figure 1 is tocouple surface temperature measurements using an infrared camera with MolecularTagging Thermometry (MTT) for gas temperature measurements. The bottom wall ofthe channel will be made of Sapphire substrate of 650 $\mu$m thickness coatedwith a thin film of Indium Tin Oxide (ITO). The average roughness of this ITOlayer is about 3 nm. The top wall of the channel will be made of SU8 and bondedwith the bottom wall with a layer of PDMS. The channel will be filled in withacetone vapor,

Proposed Design for Simultaneous Measurement of Wall and Near-wall Temperatures in Gas Microflows