Who has dealt with the calibration of an optical smoke detector?

Question

Electronics

Good afternoon. The point is the following.
There is an optical chamber from a smoke detector of the following type:

The emitter and receiver are located at an angle of 120 degrees through a partition. Those. in clean air, illumination at the noise level. Radiation in the IR range.
A question for those who have dealt with the production of such or similar sensors. What was used for calibration? The detection threshold should be from 0.5 to 2 B. But it is impossible to use a conventional optical measure, the optical density of which is normalized on the direct path of the optical signal. How to be in that case?

What should be used as equivalent smoke density for this camera geometry?

Answer 1

They put similar sensors, then they tested it: a person with a cigarette climbed onto a stepladder, inhaled and exhaled into the sensor - the sensor worked.
You need some kind of slightly cloudy crap that will scatter light - a container of water and a few drops of milk, rustic moonshine, soapy water or something like that.