Electrostatic Linear Ion Trap Research Articles

Absorption Mode Fourier Transform Electrostatic Linear Ion Trap Mass Spectrometry

In Fourier transform mass spectrometry, it is well-known that plotting the spectrum in absorption mode rather than magnitude mode has several advantages. However, magnitude spectra remain commonplace due to difficulties associated with determining the phase of each frequency at the onset of data acquisition, which is required for generating absorption spectra. The phasing problem for electrostatic traps is much simpler than for Fourier transform ion cyclotron resonance (FTICR) instruments, which greatly simplifies the generation of absorption spectra. Here, we present a simple method for generating absorption spectra from a Fourier transform electrostatic linear ion trap mass spectrometer. The method involves time shifting the data prior to Fourier transformation in order to synchronize the onset of data acquisition with the moment of ion acceleration into the electrostatic trap. Under these conditions, the initial phase of each frequency at the onset of data acquisition is zero. We demonstrate that absorption mode provides a 1.7-fold increase in resolution (full width at half maximum, fwhm) as well as reduced peak tailing. We also discuss methodology that may be applied to unsynchronized data in order to determine the time shift required to generate an absorption spectrum.

Electrostatic linear ion trap for low-energy ion beam storage

An electrostatic linear ion trap was constructed and applied to the storage of an He ion beam of kinetic energy 208 eV. The time-of-flight detection of the stored ions confirms the validity of its storage performance. It is shown that the interaction with the residual gas plays a crucial role in the loss mechanism of the stored ions. The lifetime of the stored ions, which was measured to be 5.25 ± 0.65 mS in the present study, with modest vacuum conditions, is expected to lengthen substantially with ultra-high vacuum conditions.

Lifetime measurement ofBe−(2s2p24P3/2)using an electrostatic ion trap

The lifetime of the metastable ${\mathrm{Be}}^{\ensuremath{-}}{(2s2p}^{2}{}^{4}{P}_{3/2})$ state is measured using an electrostatic linear ion trap which stores keV-ion beams. Trapping using electrostatic fields avoids the complication of magnetic-field-induced mixing effects which can interfere with the measurement of the spontaneous decay. The result is found to be $42.07\ifmmode\pm\else\textpm\fi{}0.12\ensuremath{\mu}\mathrm{s},$ which is a factor of 40 better in accuracy than the previous result determined in a heavy-ion storage ring. The measured lifetime is found to be 30% longer than the most recent theoretical value.