This kind is the cheapest and the most common type found in people's homes. One minutes and 43 seconds later the ionization smoke detector goes off. It takes another two minutes more before the photoelectric smoke detector beeps. Finally, we lit diesel on fire. Which means it could block your senses to find your way out if your not warned early enough.
All smoke detectors have clear labeling of either ionization or photoelectric.
You could jot down the model number and try to match it with one in a store to tell which kind you have. The Oklahoma City Fire Department gives away free ionization smoke detectors all year long. All you have to do is give them a call at 297-3318.