What is the cross-response of a sensor?

Cross-response refers to the characteristic of a gas sensor to respond to gases other than the target gas. Depending on the nature of how different gases interact with the sensor, the sensor’s output signal may sometimes weaken (negative cross-response) or sometimes strengthen (positive cross-response). Cross-response can interfere with the sensor’s measurement signal; particularly in the case of negative cross-response, it can attenuate the sensor’s response to the target gas, thereby delaying the instrument’s alarm—making it more hazardous. The cross-response coefficient (CF) is used to quantify the sensor’s cross-sensitivity; using the CF value, a sensor calibrated for one gas can directly measure the concentration of another gas, thereby eliminating the need to prepare numerous standard gases.