Determination of carbon in chromium by photon activation

Carbon is determined in chromium by activation in 35 MeV photons. The sample is dissolved by a fused NaOH-NaNO3 bath. Carbon dioxide is then extracted by acid dissolution of the solidified bath. A limit of detection of 0.03 μg of carbon is achieved. Chromium samples are irradiated in photons emitted from a platinum target submitted to an electron beam of 35 MeV produced by a linear accelerator at C.E.N. Saclay. Two graphite foils of some mg are irradiated at the same time and are used as standards. The radioactivities of absorbers and standards are measured on a NaI detector for the annihilation γ-ray of the β+radiation. (T.G.)