SINGLE-ELECTRON AND DOUBLE-ELECTRON CAPTURE IN HE-3(2+)-H2 COLLISIONS AT LOW ENERGIES FROM 1 TO 2000 EV

The total attenuation cross section sigma(att) and the single-electron capture cross section sigma(21) in collisions of He-3(2+) with H-2 have been measured using a tandem mass spectrometer whose collision cell consists of an octopole ion beam guide. A possible scattering loss which might contribute to sigma(att) is examined, and a large part of the difference sigma(att) - sigma(21) is attributed to the double-electron capture process. As its magnitude is as large as 10(-15) cm2 at the lowest energy studied, the importance of the process is emphasized in connection with the production of fast protons through Coulomb explosion of H-2(2+).