The determination of oxygen in molybdenum and tungsten

Revel and Albert (240) and Fedoroff et al. (220) describe the determination of oxygen in molybdenum by helium-3 activation. Fedoroff et al. (220) 

The sample is dissolved after the irradiation in a mixture of 2 ml of cone. 

Valladon and Debrun (208) used triton activation for the instrumental determination of oxygen in molybdenum. Irradiations of 15 min with a 500 nA beam of 3.5 MeV tritons were carried out. After the irradiation a 5 //m surface layer was removed by a combination of chemical etching and grinding. The result obtained was (15.9 + 1.1) jug/g (n = 12). 

Faure et al. (224) irradiated with 54 MeV o-particles to determine oxygen in molybdenum. F was separated by extraction with diphenyldichioro-silane in isopropylether. 

The determination of oxygen in tungsten by helium-3 activation is described by Vandecasteele et al. (247) and by Revel and Albert (240). Vandecasteele et al. (247) irradiated for 20 min with a 1.5 mA beam of 20 MeV helium-3. The sample was chemically etched in a 1/1 mixture of hydrofluoric and nitric acids, rinsed and dried. The energy corresponding to the etched depth was 13.5 - 14.2 MeV. The sample was dissolved in a mixture of 10 g of sodium hydroxide, 400 mg of sodium fluoride and 2.5 g of sodium nitrate in a nickel crucible. The melt was dissolved in nitric acid and F was 

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