Yes, having the sensor inside your container, already, fill in the container with your target gas, applying a (parametric) partial[1] pressure. So, upon opening the valve, measure the sensor's output signal[2], embracing an "in-situ investigation" over time t (or Log t).

1. Ideal Gas Example Problem: Partial Pressure https://www.thoughtco.com/ideal-gas-problem-partial-pressure-609583

2. Lecture 22: Instrumentation / Sensors https://www.colorado.edu/ASEN/asen5519/22sensors.pdf

Hi Ioannis,

Maybe I didn't explain my question clear enough. I don't have problem of mixing a certain partial pressure or concentration gas mixer, or readout the sensor signal. My problems are: Firstly because gas exchange of the environment and the sensor cell is by diffusion through the 30 um gap, gas flow induced by container valve opening will accelerate the gas exchange process. This presumably shortens the response time I measure. Secondly, my sensor is connected by optical fibers to couple light beam in and out of the sensor to detect gases, which means I can not fully close the gas container after the sensor was placed in. So there will be gas leaking through that opening. I guess it also affects the response time I measure.

So the ideal situation would be the sensor goes from 0% CO2 environment into a 5% CO2 environment without cause much gas flow. But I feel this is not practical. It would be good to know how the response time parameter of other diffusion based gas sensors are calibrated.

Hi Sheng,

it is more clear, now, and I wish you to find successive response(s), shortly.