Patterns of ion distributions from a cylindrical 63 Ni foil in an ion mobility spectrometer

Ion distributions in the 38 mm cross section of a drift tube for ion mobility spectrometry were determined using a charge accumulation IonCCD with imaging capability of 2126 pixels each 21 μm wide. A 10 mCi ⁶³Ni ion source with concentric cylinder geometry was examined experimentally using a drift tube with compressed rings separated by sapphire balls. Results were compared to computational findings from SIMION to learn the influence of source geometry on equipotential contours and on beam shapes. Swarms of ions formed in air at ambient pressure were shaped though field contours into ion beams which retained shape over the 45 mm drift length in an electric field of 30 V/mm. The IonCCD images revealed subtle beam alignments from azimuthal asymmetry of the source and holder not possible to see in a simple Faraday plate detector. Double slit experiments demonstrated a capability to shape ion beams with mechanical structures over a drift tube cross section.