Microsecond Dynamic Response Calibration of ITO Thin-Film Thermocouples Under Laser and Detonation Conditions

In this work, we designed and built two types of calibration devices to study the dynamic characteristics of the indium tin oxide (ITO) thin-film thermocouples (TFTCs) under different conditions. The first device, based on a nanosecond laser, generates a 150-mW heat pulse within 25 ns, and the experimental analysis of the cooling process reveals the dynamic characteristics of the ITO TFTCs under natural convection conditions. The second device uses a detonation wave that generates a $270~^{\circ }$ C airflow environment in 400 ns at 4.86 Mach, representing forced convection conditions. Experimental results show that in the nanosecond laser experiment, the time constant of the ITO TFTC is $122.08~\mu $ s, corresponding to a frequency response of 1.30 kHz. In contrast, in the detonation wave experiment, the time constant of the ITO TFTCs decreases to $15.65~\mu $ s and the frequency response increase to 10.17 kHz. These results demonstrate that the dynamic characteristics of the ITO TFTCs are not constant and can be significantly influenced by the measurement environment.