Direct heat flux measurement is an important task in various fields of industry. It can also be used in a multitude of medical applications. Traditional heat flux sensors typically generate voltage by Seebeck effect. Because the generated voltage is parallel to the heat flux, the sensors usually consist of stacked thermopiles. Stacking thermopiles increases the voltage output, but also the thickness of the sensor, which in turn hampers the sensor's response time and makes it physically larger. A new type of heat flux sensor, called the Gradient Heat Flux Sensor (GHFS) has recently been developed. The sensor is based on transverse Seebeck effect, in which the thermal emf generated is perpendicular to the heat flux. This facilitates the stacking of tilted thermopiles in direction perpendicular to the heat flux, which means that the sensor itself can be made very thin, solving many problems of the older designs. This study was a comparative analysis between traditional temperature sensors and various Gradient Heat Flux Sensors. The sensors were heated using a pulsed diode laser, and the response characteristics were compared with each other. It was observed that traditional temperature sensors have response time from hundreds to thousands of microseconds, whereas the Gradient Heat Flux Sensors have response time in order of microseconds. Furthermore, the heat flux sensors are less affected by heat accumulation than temperature sensors.
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