Spatial harmonics of linear multipoles with round electrodes

Konenkov, A. N.; Douglas, D. J.; Konenkov, N. V.

doi:10.1016/j.ijms.2009.10.007

Cited by 13 publications

(17 citation statements)

References 11 publications

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“…The potential Φ( x , y , t ) generated by a quadrupole round rod set is given by:

normalΦ ((),,, x, y, t) = V_{r f} R e ((), true \sum_{N = 2}^{\infty} A_{N} {(\frac{x + i y}{r_{0}})}^{N}) c o s normalΩ t ≅ V_{r f} R e ((), true \sum_{N = 2}^{10} A_{N} {(\frac{x + i y}{r_{0}})}^{N}) c o s normalΩ t

where Ω is the angular frequency of the rf field, A N is the dimensionless amplitude of a multipole of order N ,

i = \sqrt{- 1}

, and r 0 is the field radius. For the case of identical rods and a symmetrical rod set, the higher order harmonics have N = 6, N = 10, N = 14, … .…”

Section: Methodsmentioning

confidence: 99%

“…The normalized multipole amplitudes A N were calculated with the method used by Konenkov et al . (Read used a similar method with rings of charge …”

Section: Methodsmentioning

confidence: 99%

“…The normalized multipole amplitudes A N were calculated with the method used by Konenkov et al [20] (Read used a similar method with rings of charge. [21] ) The complex potential F(z) of a multipole rod set of order 2K (2K rods, K = 2 for a quadrupole) at a point z is written as:…”

Section: Simulation Of the Ion Motion With Higher Spatial Harmonicsmentioning

confidence: 99%

“…The theoretical description of the dipolar excitation process with the addition of weak spatial harmonics with the effective potential [9] model is complicated because of limitations in determining the effective potential at q values greater than about 0.40. Thus, we use direct calculations of ion trajectories as used by Gibson and Taylor, [18] Douglas and Konenkov, [19] and Konenkov et al [20] The simulations here can be applied to both radial ejection, where ions must be excited until they reach a rod, [5] and axial ejection, where ions must be excited to large oscillation amplitudes. [2][3][4] Here we report a study of the effects of the ratio of rod diameter, r, to field radius, r 0 , on peak shape and mass resolution, with mass-selective ejection of ions from a linear quadrupole ion trap.…”

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confidence: 99%

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Mass resolution of linear quadrupole ion traps with round rods

Douglas

Konenkov

2014

Rapid Comm Mass Spectrometry

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“…The potential Φ( x , y , t ) generated by a quadrupole round rod set is given by:

normalΦ ((),,, x, y, t) = V_{r f} R e ((), true \sum_{N = 2}^{\infty} A_{N} {(\frac{x + i y}{r_{0}})}^{N}) c o s normalΩ t ≅ V_{r f} R e ((), true \sum_{N = 2}^{10} A_{N} {(\frac{x + i y}{r_{0}})}^{N}) c o s normalΩ t

where Ω is the angular frequency of the rf field, A N is the dimensionless amplitude of a multipole of order N ,

i = \sqrt{- 1}

, and r 0 is the field radius. For the case of identical rods and a symmetrical rod set, the higher order harmonics have N = 6, N = 10, N = 14, … .…”

Section: Methodsmentioning

confidence: 99%

“…The normalized multipole amplitudes A N were calculated with the method used by Konenkov et al . (Read used a similar method with rings of charge …”

Section: Methodsmentioning

confidence: 99%

Section: Simulation Of the Ion Motion With Higher Spatial Harmonicsmentioning

confidence: 99%

mentioning

confidence: 99%

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Mass resolution of linear quadrupole ion traps with round rods

Douglas

Konenkov

2014

Rapid Comm Mass Spectrometry

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“…simulations. Its relevant characteristics are an inner radius of r 0 = 0.2 mm and an electrode radius of r 0 /3, which corresponds to the optimisation of the octupole potential [16]. The calculation shows that the actual quadrupole potential deviates from the ideal one but keeps the quadrupole symmetry.…”

mentioning

confidence: 96%

Parallel ion strings in linear multipole traps

et al. 2011

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Additional radio-frequency (rf) potentials applied to linear multipole traps create extra field nodes in the radial plane which allow to confine single ions, or strings of ions, in totally rf field-free regions. The number of nodes depends on the order of the applied multipole potentials and their relative distance can be easily tuned by the amplitude variation of the applied voltages. Simulations using molecular dynamics show that strings of ions can be laser cooled down to the Doppler limit in all directions of space. Once cooled, organized systems can be moved with very limited heating, even if the cooling process is turned off.Radio-frequency (rf) traps are very useful tools for a wide range of research interests such as high resolution spectroscopy [1], frequency standards [2], quantum information processing [3] and quantum simulations [4]. The ability to trap and cool atomic or molecular species in a well defined manner allows to control and study the quantum behaviour of these systems. Most experiments require a totally perturbation-free dynamics of the confined ions, and the micro-motion due to the rf trapping field can sometimes be a disturbing factor. In these cases, cold ions are confined in a string configuration along the longitudinal axis of a linear quadrupole trap, where the rf field vanishes. For a number of applications, in particular in quantum logic and quantum simulations [3,4], it could be desirable to create more sites inside a trap where the ions do not undergo the rf parametric excitation. Linear traps of higher order, here called multipole traps, offer larger regions of low rf electric fields [5] which allow to trap large samples with a reduced driven micromotion, as compared to the same sample trapped in a linear quadrupole trap [6]. Local minima can be induced in the trapping potential by adding static voltages to these multipole rf voltages [7,8] but the ions then undergo a rf driven motion which is detrimental when very low temperatures need to be reached. The superimposition of a lower order rf field onto the main trapping field generates minima to the trapping potential where the rf field is nulled. In such a configuration and depending on their number, the ions can settle in each minimum as individual ions or as parallel strings of ions expanding in the axial direction. Due to the absence of a local rf electric field, laser cooling can reduce the temperature of the ions as low as for a chain of ions in a quadrupole trap.In this letter we first give an example of principle of the proposed method by combining a quadrupole potential with the potential created by a linear octupole trap. To demonstrate how to reach the Doppler limit by Doppler laser cooling we use molecular dynamics (m.d.) simulations of a 10-ion system, in a double line configuration. In a second part, we discuss the general case of two combined rf potentials of different order. In these two parts, * mathieu.marciante@etu.univ-provence.fr we assume an ideal electric field for each superimposed rf field. In the third ...

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Current literature in mass spectrometry

2010

J. Mass Spectrom.

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Spatial harmonics of linear multipoles with round electrodes

Cited by 13 publications

References 11 publications

Mass resolution of linear quadrupole ion traps with round rods

Mass resolution of linear quadrupole ion traps with round rods

Parallel ion strings in linear multipole traps

Current literature in mass spectrometry

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