Cooling of direct current beams of low mass ions
V.Koslovskya, K.Fuhrerb, A.Tolmacheva, A.Dodonova, V.Raznikova,H.Wollnikb
aInstitute of Chemical Physics, Chernogolovka, Russia
bII. Physikalisches Institut, Universitat Giessen, D-35392 Giessen, Germany
Collisional focusing of low mass ions of 1-40 eV is investigated in a rf-only quadrupole. The final ion intensities and energies are monitored by an orthogonal-extracting time-of-flight mass spectrometer. It was found that in this energy range Na+ and K+ ions can be cooled and focused as well as Cs+ ions if the residual gas pressure in this “quadrupole beam cooler” is high enough that each ion undergoes several collisions.
© 1998 Elsevier Science B.V.