ocr: GAMMA RAYS All electromagnetic radiation with a wavelength below 0.1 À (angstrom) is called gamma radiation. Gamma radiation is produced in radioactive decay and nuclear reactions. Neutron stars are powertul gamma radiators. The penefration power of gamma particle resulting from radioactive decay is strong; it can penefrate very deep into a substance (for example, through a 10 cm thick aluminium sheet) before being absorbed. Gamma rays cannot penetrate the Earth's atmosphere, so gamma ray observa- tions have to be conducted on satellites. One nm (nanometre) equals 10 A (angstrôm) = 10-10 metre ...
