Bob:

I believe that if there were any risk of radiation damage from the smoke detector, there would be warning signs on new detectors saying not to install them in the bedrooms of small children and pregnant women.

However, the smoke detector shouldn't be in the bedroom, it should be outside the bedroom door, but within 4 feet of the bedroom door when looking down from space.

That's because, unless the person is a smoker and is in the habit of smoking in bed, the chances of a fire starting in the bedroom are slim. So, putting a smoke detector in the bedroom, and then sleeping with the bedroom door closed is going to prevent that detector from detecting smoke. By the time it does, your bedroom door is burning and you're trapped in the bedroom with no escape except the bedroom window, if there is one.

Better to put the smoke detector outside the bedroom but within 4 feet of the door. That way if a fire starts in the house at night, the smoke detector will detect the smoke much earlier, and will still be close enough to the bedroom to wake up anyone inside.

And, never put a smoke detector closer than 4 inches to the corners where walls meet ceilings. In a fire, the air in those areas is relatively stagnant, and the smoke detector in those corner areas will be slow to detect smoke.

So, I'd move the smoke detector, but not for the reason you were thinking.