Radiation testing. Technician closing the sample chamber of a gamma spectrometer, used to measure a sample's gamma radiation level. The walls and ceilings of the laboratory are lined with copper to help prevent any radiation leaks. The sample (not seen) could be of earth, plant material or animal matter. Radioactive pollution may arise from nearby nuclear power stations or natural sources. Regardless of its source, ionising radiation, such as gamma radiation, can cause severe health problems during prolonged exposure. This work is being done at the French government agency, l'Insitut de Protection et de Secrete Nucleaire (IPSN), at Saclay, France.