Hi, I'm a new member in the forum. I own two similar GM military grade meters with calibration certificates, calibrated for gamma-rays metering and each one has two tubes filled with helium, argon (or neon), halogen (or quenching) gases. When I am exposed to some radiation source, my GM meter shows dose rate of about 300 microR per hour, but scientific proportional gamma-rays dose-meter (also has calibration certificate), at the same moment is following to display background's gamma radiation numbers of about 7 microRentgen per hour. I suspect, that my GM meters are measuring secondary gamma radiation caused by neutron radiation, born in their own tubes by the process of thermal neutron capture (or recoil) in helium-argon gas and then, the exposure radiation must be built of neutrons. Here in forum I saw discussion in the following thread: Is it possible, that my GM gamma-meter is sensitive to neutron radiation too? If yes, which physical mechanism should give GM gamma meter sensitivity for neutron radiation? Thank you.