Double-to-single target ionization ratio for electron capture in fast p-He collisions

H T Schmidt; A Fardi; R Schuch; S H Schwartz; H Zettergren; H Cederquist; L Bagge; H Danared; A Källberg; J Jensen; K-G Rensfelt; V Mergel; L Schmidt; H Schmidt-Böcking; C L Cocke

doi:10.1103/PhysRevLett.89.163201

Double-to-single target ionization ratio for electron capture in fast p-He collisions

Phys Rev Lett. 2002 Oct 14;89(16):163201. doi: 10.1103/PhysRevLett.89.163201. Epub 2002 Sep 27.

Authors

H T Schmidt¹, A Fardi, R Schuch, S H Schwartz, H Zettergren, H Cederquist, L Bagge, H Danared, A Källberg, J Jensen, K-G Rensfelt, V Mergel, L Schmidt, H Schmidt-Böcking, C L Cocke

Affiliation

¹ Department of Physics, Stockholm University, Sweden.

PMID: 12398718
DOI: 10.1103/PhysRevLett.89.163201

Abstract

We have used the ion storage ring CRYRING and its internal gas-jet target and recoil-ion-momentum spectrometer to measure absolute cross sections for transfer ionization (TI: p+He-->H0+He2++e(-)) in 2.5-4.5 MeV p-He collisions with separate Thomas (TTI) and kinematic (KTI) TI contributions. The probability for electron emission in kinematical capture decreases with increasing velocity and appears to approach the photoionization shakeoff value (1.63%) [T. Aberg, Phys. Rev. A 2, 1726 (1970)]]. The velocity dependence of the TTI cross section is consistent with the theoretically predicted v(-11) scaling [J. S. Briggs and K. Taulbjerg, J. Phys. B 12, 2565 (1979)]].