Airplane flight radiation exposure,
and what the airlines never told you!
(or fun with Radiation Monitors)

Did you know that when you travel on an airplane at altitudes of 34,000 to 37,000 feet, you are being exposed to varying radiation levels of about 260 to 280 counts per minute (CPM)? Cosmic radiation levels depend on your altitude, latitude and the amount of solar activity. Background radiation at sea level is about 10 CPM. After Chernobyl, I was living about 40 miles from a nuke, and being the hobbyist I am, I built the Heathkit Radiation Monitor, and took it on an airplane trip to monitor cosmic radiation at high altitude. It was amazing to see the radiation levels you are exposed to while flying at high altitude.

Although Heathkit is no longer in business, you can buy this kit from S.E. International

Magnetic Levitation - Science is Fun