NEW CRUCIBLE FOR NOBLE GAS EXTRACTION

Abstract

Traditional Crucibles for noble gas extraction made of refractory metals are not suitable for metallic samples because these are easily alloyed with liquid metals. To obtain elemental and isotopic compositions of noble gases from metallic samples, new materials, i.e., single crystal MgO and hot-pressed BN have been carefully examined. Low background was achieved using these new crucibles. The MgO crucible is not suitable for materials with high temperature because MgO actively evaporates about 1700°C. Inertness to metallic materials and complete degassing from metallic materials were also achieved using the BN crucible. Based on noble gas data obtained using the BN crucible, we determined the cosmic exposure age of the Mundrabilla iron meteorite as 350+/-90 Ma.