Nonlinear resonances in linear segmented Paul trap of short central segment

Abstract

Linear segmented Paul trap system has been prepared for ion mass spectroscopy experiments. A nonstandard approach to stability of trapped ions is applied to explain some effects observed with ensembles of calcium ions. Trap's stability diagram is extended to 3‐dimensional one using additional ∆a besides standard q and a stability parameters. Nonlinear resonances in (q, ∆a) diagrams are observed and described with a proposed model. The resonance lines have been identified using simple simulations and comparing the numerical and experimental results. The phenomenon can be applied in electron‐impact ionization experiments for mass identification of obtained ions or purification of their ensembles.

Energy transfer in elastic collisions between electrons and trapped ions

“…The apparatus used in experiment was described in our previous works [4,7,15,16]. It consists of a linear, segmented Paul trap inside a vacuum chamber.…”

“…The trap is driven with 1 ÷ 4 MHz AC voltage with several volts DC between central and outer segments of the trap. Trap settings were chosen to be away from any nonlinear resonances [16]. In this particular case, 1 MHz frequency of the trap AC voltage was used.…”

Measurement of electron-calcium ionization integral cross section using an ion trap with a low-energy, pulsed electron gun

“…The main issue of impact ionization is nonselectivity of such process, which can possibly lead to presence of unintended ion species in the trap. Such disadvantage can be however overcome by careful tuning of the trapping parameters allowing for mass selection of the trapped ions [15] using for example nonlinear resonance [29] to eject ions of chosen masses.…”