A new all-metal induction furnace for noble gas extraction

A new all-metal induction furnace for extraction of all noble gases from pyroxenes, olivines, quartz or barites has been developed a CRPG. It differs in design from other induction furnaces in that the totality of the vacuum vessel is metallic and the induction coil, normally located outside the furnace, has been placed inside the vacuum vessel, with a special radio frequency power feedthrough welded onto a flange. The volume of the crucible is approximate to 15 cm(3) and permits fusion of samples with a mass of up to 1 g. Samples are packed into a metal foil, loaded into a carousel, baked out before analysis, and then sequentially dropped into the Ta-crucible. The low weight of the crucible (approximate to 120 g) allows for short and efficient degassing cycles. When the furnace is pumped for the first time after samples loading, short cycles between 500 and 1800 degrees C a fast heating rates (approximate to 400 degrees C.min(-1)) are sufficient to achieve very low blanks. The durations of these cycles are range from 30 min for He to up to a few hours for Ne, Kr and Xe. Blanks of He, Kr and Xe (10 min heating durations) and Ne (20 min) in static vacuum are (1.6 +/- 1.0) x 10(-15) mol He-4 (T = 1750 degrees C), (5.8 +/- 2.3) x 10(-17) mol Ne-20 (T = 1500 degrees C), (2.1 +/- 0.3) x 10(-18) mol Kr-84 (T = 1700 degrees C) and (4.4 +/- 0.4) x 10(-18) mol Xe-132 (T = 1700 degrees C). Argon blanks have not yet been measured.