DOES HELIUM-3 ABUNDANCE DECREASE IN DEPENDENCE ON DEPTH AT MARE CRISIUM?

Introduction: Strong dependence of helium-3 abundance on size and composition of regolith particles imposes significant restrictions on use of the measured and published data for an estimation of the isotope resources in lunar regolith. The estimations of the helium-3 abundance received for preliminary enriched samples, i.e. for different regolith fraction in size, and also for the separate components of regolith selected to mineral, chemical or other attribute do not reflect the average abundance of the isotope in bulk regolith and cannot be used for an estimation of the general resources of this element. The optimal are the estimations received for representative samples of bulk regolith without division into fractions and components. Luna 16: Core sampling at «Luna-16» landing site was carried out to depth of 35 cm with core drilling. Mare basalts in the landing site belong to a spectral class with average Ti abundance (TiO2 4.9 %) [2]. He abundance is examined for different fractions of regolith particles (Table 1).