Particle flight times through electrostatic and magnetic sector fields and quadrupoles to second order

Matsuda, Hisashi; Matsuo, T.; Ioanoviciu, D.; Wöllnik, H.; Rabbel, V.

doi:10.1016/0020-7381(82)80061-2

Cited by 23 publications

(7 citation statements)

References 8 publications

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“…The derivations of the flight time followed the general trend of the calculations pursued in [4]. The flight time of an arbitrary ion, t, of velocity v, through the condenser is…”

Section: Methodsmentioning

confidence: 99%

“…By using the field-free space time-of-flight matrix elements of [4] the mass resolution , takes the form:…”

Section: Applicationmentioning

confidence: 99%

“…Such condensers can serve to compress radially broad ion beams or packets as it is useful to focus ions resulted from cosmic dust impact on large sensitive areas [3]. Below, the time-of-flight, longitudinal, matrix elements are given for a complete second order matrix description of the spiral main path condenser ion optics (completing a matrix like that given in Table 1 of [4]). …”

Section: Introductionmentioning

confidence: 99%

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The spiral main path electric deflector as a time-of-flight mass analyzer

Ioanoviciu

2010

International Journal of Mass Spectrometry

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“…The derivations of the flight time followed the general trend of the calculations pursued in [4]. The flight time of an arbitrary ion, t, of velocity v, through the condenser is…”

Section: Methodsmentioning

confidence: 99%

“…By using the field-free space time-of-flight matrix elements of [4] the mass resolution , takes the form:…”

Section: Applicationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The spiral main path electric deflector as a time-of-flight mass analyzer

Ioanoviciu

2010

International Journal of Mass Spectrometry

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“…We then get d, and db both connected to D if n is given: (25) (26) or by eliminating n we obtain the relation given in Ref. (27) The connection between the two ratios is represented in Fig. 5, for second-order space focusing.…”

Section: )mentioning

confidence: 98%

“…We restrict this discussion to the first order matrix elements only, of Ref. 27. For the field-free region…”

Section: Electrostatic Deflectorsmentioning

confidence: 99%

Ion‐Optical solutions in time‐of‐flight mass spectrometry

Ioanoviciu¹

1995

Rapid Comm Mass Spectrometry

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Time-of-flight mass spectrometers are able to cover mass ranges to around a half a million Da. The mass resolution of these instruments has been improved drastically by incorporation of electrostatic mirrors. The ionoptical solutions enabling these achievements and other promising features are discussed in terms of: First-and second-order space focusing in time for linear drift time-of-flight mass spectrometers; velocity focusing by time lag; ion-packet bunching in post-source impulse focusing; first-and second-order energy focusing in time, in single-and double-stage homogeneous electrostatic mirrors with normal and oblique ion incidence; gridless designs; perfect time focusing in parabolic potential and axial symmetry; cylindrical ion mirrors and toroidal electrostatic deflectors as time-of-flight mass analyzers; three electrostatic sector geometry applied in secondary ion microscopy and four toroidal sector systems for tandem mass spectrometry; poloidal electrostatic sectors. Estimation of time-of-flight mass spectrometer performance limits is discussed and the stable as well as the metastable peak shapes found in time-of-flight mass spectra.Time-of-flight (TOF) mass spectrometry possesses several outstanding and unique features:' an essentially unlimited mass range, the possibility of obtaining complete mass spectra from each ion packet, and potentially high sensitivity. To take full advantage of these features, the technique requires appropriate electronics for fast ion counting and a suitable design for the TOF mass analyser.The essential performance attributes of a mass spectrometer are its resolution, sensitivity and mass range. In time-of-flight mass spectrometry two groups of different mass ions are separated if they arrive at the detector at different times. Mass resolution of all types of mass spectrometer are defined in terms of the depth of the valley separating two equal intensity adjacent and overlapping peaks. Often the full width at half maximum (FWHM) definition is used where a valley is just discernable (Fig. 1). Other definitions require adjacent peaks to be resolved by deeper, typically by a 0% or 50%, valley (Fig. 2). To have the Gaussian peaks truly separated, as in Fig. 2, Am must be about 1.4 times greater than the FWHM resolution that is shown in Fig. 1. For TOFMS the ion cloud at the detector is the result of the convolution of the initial spatial and temporal ionic distributions: transformed by the spectrometer's transfer function. A simplified representation, as constant chargedensity cylinder^,^ operates with ion packets of circular outline the aberrations at the detector site being added as slices to that cylinder. In this case, two ion packets are completely resolved if one time channel is empty between their arrival. The FWHM definition corresponds to two packets just touching each other.The front of the packet of ions of mass m reaches the detector at some time t,, while a following packet of mass m + Am arrives tm+Am -tm later. The arrival of the second ion packet must leave en...

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Aberrations of the cylindrical mirror time‐of‐flight mass spectrometers with oblique incidence

Ioanoviciu

Cună

et al. 2005

J. Mass Spectrom.

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Aberrations of the cylindrical mirror time-of-flight mass spectrometers with oblique incidence † Classical reflectron time-of-flight mass spectrometers create ion packets and focus them in time by plane grid electrodes. 1 There are no focusing forces to act on ions directing them back to the packet axis. A substantial sensitivity increase can be expected by focusing the ion packets laterally. An ion source from three cylindrical electrodes can be combined with a cylindrical reflectron, with all the electrode surfaces having a common symmetry axis. 2 The idealized calculations assume the ion source and detector as being coincident (or at least collinear) for this geometry as well as for plane electrode reflectrons. Except linear reflectrons, 3 the real-world reflectron time-of-flight mass spectrometers are so assembled that ion paths before the mirror do not interfere with those after reflection. This is achieved by the oblique incidence of ion packet with respect to the mirror entry limit. The effect of the oblique incidence has often been neglected, as the angle of incidence is usually less than a few degrees. For a quadratic field ion mirror, the oblique incidence, in a specific case, induced flight time changes of the order of ppm. 4 Oblique-incidence effect for homogeneous, electric reflectron time-of-flight mass spectrometers can be determined with the formulas derived by Ioanoviciu et al. 5 We determined the time of flight through the cylindrical mirror of an obliquely incident ion (Fig. 1). We used the Euler-Lagrange equations in cylindrical coordinates r, ϕ, and z to derive t mirror :The following symbols were used: r 0 is the radius of the cylindrical earthed electrode, v ref is the velocity of the reference ion, D ln r max /r 0 where r max is the r-coordinate of the farthest point on the reference ion trajectory, Â is the incidence angle. For the double, longitudinal (time) and lateral focusing case, r max /r 0 D 1.339.The ion entering the mirror at ϕ i leaves it at ϕ f :We accounted also for the changes of the ion coordinate on entry into and exit from the mirror due to the angular spread of the packet as well as to the effect of the field-free spaces. 6 Finally, the ion packet is lengthened because of the oblique incidence, initial width and angular spread by t packet :Here x i and˛i are the ion distance to and angle with the packet axis, at the ion source longitudinal focus, while Â 0 is the packet-axis incidence angle. As the ion packets have the coordinates distributed between x i and Cx i and between angles ˛i and C˛i, the real resolution R cyl expressed by R normal , the ideal resolution, is: classical, homogeneous electric field, two-stage reflectrons, R class , for selected normal-incidence resolution values, R normal .As a comparison, the Á angle of Fig From the above results, we conclude that the double-focusing, cylindrical reflectron time-of-flight mass spectrometers are more sensitive to the incidence angle than the homogeneous electric field reflectrons. This fact is easy to explain as ...

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Particle flight times through electrostatic and magnetic sector fields and quadrupoles to second order

Cited by 23 publications

References 8 publications

The spiral main path electric deflector as a time-of-flight mass analyzer

The spiral main path electric deflector as a time-of-flight mass analyzer

Ion‐Optical solutions in time‐of‐flight mass spectrometry

Aberrations of the cylindrical mirror time‐of‐flight mass spectrometers with oblique incidence

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