Huh, you’re clearly right. I would have expected it to say smoke measuring ionization chamber, to distinguish it from a radiation measuring ionization chamber.

Huh, you’re clearly right. I would have expected it to say smoke measuring ionization chamber, to distinguish it from a radiation measuring ionization chamber. Interestingly, the manual explains how to handle and clean the radioactive source with only minor precautions (sec. 5.1.1).