Abstract:
The results of mass-spectrometric measurements of the helium isotope content in aluminum samples obtained at different times and under different conditions and also of the helium isotope content in iron-manganese concretions are presented. The measurement accuracy of the helium isotope content in aluminum depends on various measuring-technique-related factors: vacuum conditions, gas inleakage and escape in the mass analyzer and/or gas extraction system, the device memory effect as applied to any of the helium isotopes, preparation accuracy of reference samples, their persistence, etc. In the given case, the statistical processing of measurement data with different criteria indicates that the variances diverge considerably but does not discover the sources of divergence. To measure the helium isotope content in iron-manganese concretions, a powdered sample is placed in a metallic capsule, which is then thrown into a heated crucible in vacuum, where gases to be tested liberate. Our statistical analysis of measuring data confirms the supposition that, if the capsule is made of low-melting aluminum and the capsule with a fine powder is thrown into a heated crucible, the variance grows and measuring data are underestimated. This seems to be associated with rapid melting of the capsule, emission of fine particles of the sample out of the hot zone of the reactor, and their loss. When the capsule is made of nickel, a much higher melting material than aluminum, it does not melt and the test material is not ejected from the hot zone. That is what follows from the results of the statistical analysis in our opinion.
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