Precision electromagnet for a mass spectrometer

Magnetic resonance and radio frequency mass spectrometers and their application

“…To further improve the analytical performance of the MRMS and to study the influence of various parameters on these characteristics, a novel method describing ion motion in the mass analyzer was developed [81]. In contrast to the approach employed in Ref.…”

“…One also sets the magnetic field B 0 , amplitude of the modulator voltage U, ion mass and charge m/q, and all geometric dimensions of the analyzer specified above in the consideration of Ref. [81]. Equations of ion motion were composed for all 10 sections, the final conditions of ion flight in the first section becoming the starting conditions for the second section, and so on.…”

“…Breaking up the trajectory of ion motion in the MRMS into 10 parts [81] was used in calculation of the instrument with a resolving power R 0.5 h ∼ 10 6 . Another approach employed for this purpose is described in Ref.…”

“…This technique permits one to map accurately the magnetic field and calculate the correction to the cyclotron period for a given ion species with a high precision. As another example, several MRMSs incorporate ion sources [49,50] whose ion optical systems incorporate crossed three-electrode lenses to focus the beams of the ions under study in two mutually perpendicular directions, an approach that made possible considerable enhancement of instrument sensitivity,…”

“…To reduce the dark current due to the tritium ␤ electrons, an ion beam detector was developed [80] that was based on transformation of ions into secondary electrons which are accelerated to an energy of ∼30 keV, i.e., higher than the maximum ␤ electron energy (∼18.6 keV), and strike the scintillator. The scintillator is coated by a layer of photoresist of a specified thickness, which, while stopping the ␤ electrons, lets the accelerated electrons pass, to be recorded subsequently in the single counting mode.…”