Sputtering of meteorites by He+, Ne+, and Ar+ ions

Abstract

This letter gives some measurements on the erosion of meteorites by He+ and Ne+ ions. The experiments were performed in the isotope separator of the Laboratory for Mass Separation as described in a previous article on sputtering by Ar+ ions [Heymann and Fluit, 1962], The He+ sputtering coefficient for the Canyon Diablo meteorite has been measured by a technique different from that described previously because the removed material was too small to be measured by weighing. In this technique, the meteorite was irradiated with slow neutrons in the Argonaut reactor of the Reactor Centrum Nederland, Petten. The irradiated target was mounted inside a glass sphere at an angle of 45° to the separator ion beam, which entered the sphere through a circular hole (Figure 1). The sputtered material was deposited on the inside of the sphere. A small fraction (<10 per cent) was lost through the entry hole. The sputtered material was dissolved in acid containing cobalt, iron, and nickel carriers. The cobalt was isolated with an anion-exchange resin and electroplated on platinum disks, and the Co60 activity was measured in a proportional counter of low background.