A Parallel Miniature Cylindrical Ion Trap Array

and, Ethan R. Badman; Cooks, R. Graham

doi:10.1021/ac000109p

Cited by 77 publications

(68 citation statements)

References 49 publications

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“…A small amount (20 mg) was placed in a stainless steel cup directly in front of the ion source, where it sublimed at a rate sufficient to raise the chamber pressure to between 5 x 10 -7 and 1 x 10 -6 Torr. 25 Figures 8 and 9 show mass spectra for the two compounds, obtained using devices equipped with 4mm and 2 mm pre-filter electrodes, respectively. In each case, the ion energy was V A = 2 eV and no pre-filter bias was used.…”

Section: Mass Rangementioning

confidence: 99%

“…Particular attention has been devoted to cylindrical ion traps (CITs), since these may be easily constructed as planar arrays [22][23][24][25], and several portable systems containing CITs have been demonstrated [26][27][28][29]. More recently, microfabricated ion traps have been demonstrated in cylindrical [30][31][32][33], toroidal [34] and linear [35][36][37] arrangements.…”

Section: Introductionmentioning

confidence: 99%

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Microfabricated Quadrupole Mass Spectrometer With a Brubaker Prefilter

Wright¹,

O'Prey²,

Syms

et al. 2010

J. Microelectromech. Syst.

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Microfabricated quadrupole mass spectrometers with Brubaker pre-filters are demonstrated for the first time. Complete filters are assembled from two dies, each carrying two pairs of rods providing the pre-filter and main filter sections. The rods are held in precision silicon mounts that are fabricated using wafer scale deep reactive ion etching and anodic bonding to glass substrates. Improvements to ion transmission are obtained by tuning the bias potential applied to the pre-filter. The effect is explained in terms of a simple analytic theory for ion motion in the pre-filter. Mass filtering with a range of m/z = 0-1200 and a resolution of m/Δm ≈ 150 at 10% of peak height is demonstrated using 2-4 mm long pre-filter electrodes, 30 mm long main electrodes (both of 650 µm diameter) and a RF drive at ≈ 6.5 MHz.

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Section: Mass Rangementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microfabricated Quadrupole Mass Spectrometer With a Brubaker Prefilter

Wright¹,

O'Prey²,

Syms

et al. 2010

J. Microelectromech. Syst.

View full text Add to dashboard Cite

show abstract

“…For miniaturized traps, however, machining methods have been pushed to the limit, and simpler electrode geometries such as planar and cylindrical are required. For this reason, most miniaturized and microfabricated ion traps have utilized the cylindrical trap design [12,[16][17][18][19][20].The need for a portable mass spectrometer has largely driven efforts to produce miniaturized ion traps [21]. Although the mass analyzer is just one of several components of a complete mass spectrometer system, miniaturization of the mass analyzer can often reduce the size and weight of other components.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

Novel ion traps using planar resistive electrodes: Implications for miniaturized mass analyzers

Austin

Peng

Hansen

et al. 2008

J. Am. Soc. Mass Spectrom.

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In radiofrequency ion traps, electric fields are produced by applying time-varying potentials between machined metal electrodes. The electrode shape constitutes a boundary condition and defines the field shape. This paper presents a new approach to making ion traps in which the electrodes consist of two ceramic discs, the facing surfaces of which are lithographically imprinted with sets of concentric metal rings and overlaid with a resistive material. A radial potential function can be applied to the resistive material such that the potential between the plates is quadrupolar, and ions are trapped between the plates. The electric field is independent of geometry and can be optimized electronically. The trap can produce any trapping field geometry, including both a toroidal trapping geometry and the traditional Paul-trap field. Dimensionally smaller ion trajectories, as would be produced in a miniaturized ion trap, can be achieved by increasing the potential gradient on the resistive material and operating the trap at higher frequency, rather than by making any physical changes to the trap or the electrodes. Obstacles to miniaturization of ion traps, such as fabrication tolerances, surface smoothness, electrode alignment, limited access for ionization or ion injection, and small trapping volume are addressed using this design. analysis is accomplished using radiofrequency quadrupolar potentials in at least two dimensions. In the Paul trap, three hyperboloidal electrodes trap ions in all three dimensions. In the rectilinear and linear traps, DC potentials on end plates trap ions in the third dimension. In the toroidal ion trap, the two-dimensional trapping field forms a closed loop.In all ion trap variations, metal electrodes are used to produce the appropriate electric fields. For full-sized ion traps, modem machining equipment easily produces the hyperboloidal electrode surfaces of the quadrupole ion trap. For miniaturized traps, however, machining methods have been pushed to the limit, and simpler electrode geometries such as planar and cylindrical are required. For this reason, most miniaturized and microfabricated ion traps have utilized the cylindrical trap design [12,[16][17][18][19][20].The need for a portable mass spectrometer has largely driven efforts to produce miniaturized ion traps [21]. Although the mass analyzer is just one of several components of a complete mass spectrometer system, miniaturization of the mass analyzer can often reduce the size and weight of other components. For example, the amplitude of ion motion is reduced in a small ion trap, so the mean free path of ions can be smaller (or

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“…The dimensions of some of these mass analyzers are about a millimeter or smaller. As mass analyzer dimensions decrease, vacuum requirements also typically decrease due to the shorter ion path and correspondingly shorter tolerable mean free path [11,18]. Similarly, power requirements typically decrease as the sizes of capacitive and inductive components are reduced, or as the required voltage needed for a given field strength decreases.…”

mentioning

confidence: 99%

Simulations of ion trapping in a micrometer-sized cylindrical ion trap

Austin

Cruz

Blain

2006

J. Am. Soc. Mass Spectrom.

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We have performed detailed SIMION simulations of ion behavior in micrometer-sized cylindrical ion traps (r 0 ϭ 1 m). Simulations examined the effects of ion and neutral temperature, the pressure and nature of cooling gas, ion mass, trap voltage and frequency, space-charge, fabrication defects, and other parameters on the ability of micrometer-sized traps to store ions. At this size scale voltage and power limitations constrain trap operation to frequencies about 1 GHz and rf amplitudes of tens of volts. Correspondingly, the pseudopotential well depth of traps is shallow, and thermal energies contribute significantly to ion losses. Trapping efficiency falls off gradually as q z approaches 0.908, possibly complicating mass-selective trapping, ejection, or quantitation. Coulombic repulsion caused by multiple ions in a small-volume results in a trapping limit of a single ion per trap. If multiple ions are produced in a trap, all but one ion are ejected within a few microseconds. The remaining ion tends to have favorable trapping parameters and a lifetime about hundreds of microseconds; however, this lifetime is significantly shorter than it would have been in the absence of space-charge. Typical microfabrication defects affect ion trapping only minimally. We recently reported (IJMS 2004, 236, 91-104) n parallel with advances in micromachining technology, numerous efforts are underway to produce miniaturized and microfabricated analytical instrumentation. Although portable instruments rarely match the performance of larger laboratory instruments, the benefits of low mass and power make small instruments well-suited for real-time in-field analytical applications. Mass spectrometers are attractive targets for miniaturization because they generally exhibit high sensitivity and chemical specificity. Many groups have focused on miniaturizing mass spectrometers, and small mass analyzers based on time-of-flight [1][2][3][4][5][6], magnetic sector [7], linear quadrupole [8], and hyperbolic and cylindrical ion traps [9 -17] have recently been described. The dimensions of some of these mass analyzers are about a millimeter or smaller. As mass analyzer dimensions decrease, vacuum requirements also typically decrease due to the shorter ion path and correspondingly shorter tolerable mean free path [11,18]. Similarly, power requirements typically decrease as the sizes of capacitive and inductive components are reduced, or as the required voltage needed for a given field strength decreases. Further reductions in size, for example, down to the micrometer range, may allow sufficiently small pumping, power, and electronics packages as to make a truly hand-held instrument.We recently reported [19] on the design considerations and development of microfabricated arrays of cylindrical ion traps for use as mass analyzers. These arrays contain up to 10 6 traps/cm 2 . The geometry of the cylindrical ion trap is amenable to multi-level microfabrication techniques, and the trap size and electrical requirements make it suitable for layout a...

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A Parallel Miniature Cylindrical Ion Trap Array

Cited by 77 publications

References 49 publications

Microfabricated Quadrupole Mass Spectrometer With a Brubaker Prefilter

Microfabricated Quadrupole Mass Spectrometer With a Brubaker Prefilter

Novel ion traps using planar resistive electrodes: Implications for miniaturized mass analyzers

Simulations of ion trapping in a micrometer-sized cylindrical ion trap

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