MeV-SIMS capillary microprobe for molecular imaging

Imaging of Organic Samples with Megaelectron Volt Time-of-Flight Secondary Ion Mass Spectrometry Capillary Microprobe

“…In the last 15 years, several accelerator facilities have installed MeV Time-of-Flight SIMS setups and started to use this technique routinely. − Usually, magnetic or electrostatic lenses are used to focus the primary beam. One disadvantage of this kind of beam focusing is its inability to focus heavy primary ions with high energy (such as 20 MeV Iodine) which have been shown to produce a higher secondary ion yield. ,,, One cheap and relatively simple alternative is beam collimation with borosilicate capillaries with an exit diameter of a few micrometers. − In this way, any primary beam that can be delivered by the accelerator will be collimated to approximately the same dimension, independently of ion mass and energy. Another advantage of capillaries is the possibility of beam extraction into the air without an additional window which separates the high-vacuum part of the setup and negatively affects the beam spot size.…”

Fluence enhancement of a 4 MeV-C4+ ion beam transmitted through a cylindrical glass channel after charging

“…For the latter, no scenario is generally accepted, although several models including the small-angle multiple scattering 18) (a similar process to the surface channeling) 20) and numerous charge patch assisted processes [21][22][23][24][25] have been proposed. Furthermore, the beam guide effect of MeV ions has been applied to in-air analysis processes, such as particleinduced X-ray emission spectroscopy, [32][33][34][35] Rutherford backscattering spectroscopy, 36) single-cell irradiation, 19,37) MeV secondary-ion mass spectrometry with a capillary microprobe, 38) microbeam nuclear reaction analysis, 39) and scanning transmission ion microscopy, 40,41) because mediumenergy proton and helium-ion beams can transmit through air. Furthermore, tapered glass capillaries are generally employed in this case because they can easily focus mediumenergy ion beams with diameters in the mm range to afford those with a diameter in the μm or nm range.…”

Development of MeV TOF-SIMS capillary microprobe at the Ruđer Bošković Institute in Zagreb

“…The major limiting factor of this technique is inability of proper focusing of high energy heavy ions which are bringing the highest benefit through their large electronic stopping power values with the existing standard magnetic quadrupole lenses. One way to overcome this problem is to use alternative setup: instead of using ion optical lens system, one can use capillary microprobe system where the primary beam is collimated by passing through the small opening of glass capillary [5,10,11]. The target beam current in that case is not merely defined by ratio of input and output radii of the capillary, but also depends on the capillary shape and material.…”