I got a new radiation detector for Christmas. It is a Mazor PRM-9000 with a Halogen quenched pancake flat G-M sensor, which is a bit more sensitive compared to the more common vertical tubes. Compared to my other counters it is second in sensitivity, and has good response to alpha, beta, gamma, and x-rays.

I did some calibrations using my CS-137 source, and took it on a flight to do some measurements.

As expected, you can see the increase in exposed radiation with altitude, as well as the decrease in radiation exposure as we traveled to lower geomagnetic latitudes. The reduction while traveling towards the equator is due to protective qualities of the earth’s magnetic field. ( the field at ther equator is almost perpendicular to cosmic particles, which are mostly protons at >10^8 Mev, so only particles with sufficient energy can pass through).

It is always good to see the data match with the theory. If you don’t test and calibrate a sensor it is just a well formed piece of rock.