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Time-of-flight mass spectrometer with improved resolution
W. C. Wiley,I. H. McLaren +1 more
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In this paper, a new type of ion gun is described which greatly improves the resolution of a nonmagnetic time-of-flight mass spectrometer, and the focusing action of this gun is discussed and analyzed mathematically.Abstract:
A new type of ion gun is described which greatly improves the resolution of a nonmagnetic time‐of‐flight mass spectrometer. The focusing action of this gun is discussed and analyzed mathematically. The validity of the analysis and the practicability of the gun are demonstrated by the spectra obtained. The spectrometer is capable of measuring the relative abundance of adjacent masses well beyond 100 amu.read more
Citations
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Velocity map imaging of ions and electrons using electrostatic lenses: Application in photoelectron and photofragment ion imaging of molecular oxygen
TL;DR: In this paper, the photodissociation processes occurring in molecular oxygen following the two-photon 3dπ(3Σ1g −) Rydberg excitation around 225 nm are presented to show the improvement in spatial resolution in the ion and electron images.
Journal ArticleDOI
Mass Spectrometry in Proteomics
TL;DR: 4. Automated Interpretation of CID Spectra 282 5. Accurate Mass Tags 282 C. Protein Identification in Complex Mixtures 282 D. Analysis of Protein Expression 284 III.
Journal ArticleDOI
The Orbitrap: a new mass spectrometer
TL;DR: The Orbitrap as mentioned in this paper is a mass analyzer based on an electrospray ionization source (ESI) with an outer barrel-like electrode, coaxial with the inner spindlelike electrode and mass/charge values measured from the frequency of harmonic ion oscillations along the axis of the electric field, undergone by the orbitally trapped ions.
Journal ArticleDOI
Atomic and molecular electron affinities: photoelectron experiments and theoretical computations.
Jonathan C. Rienstra-Kiracofe,Gregory S. Tschumper,Henry F. Schaefer,Sreela Nandi,G. Barney Ellison +4 more
TL;DR: Theoretical D determination of Electron Affinities and Statistical Analysis of DFT Results ThroughComparisons to Experiment and Other theoretical Methods and Specific Theoretical Successes 251E.
Journal ArticleDOI
Role of Accurate Mass Measurement (±10 ppm) in Protein Identification Strategies Employing MS or MS/MS and Database Searching
TL;DR: This work explores the advantage of using accurate mass measurement (and thus constraint on the possible elemental composition of components in a protein digest) in strategies for searching protein, gene, and EST databases that employ mass values alone, fragment-ion tagging derived from MS/MS spectra, and de novo interpretation of MS/ MS spectra.
References
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Journal ArticleDOI
A Pulsed Mass Spectrometer with Time Dispersion
M. M. Wolff,W. E. Stephens +1 more
TL;DR: In this article, an improved design of a pulsed mass spectrometer using linear time of flight analysis has been completed, achieving a peak width of two mass units at mass 40 and a linear mass scale.
Journal ArticleDOI
New Time-of-Flight Mass Spectrometer
TL;DR: In this paper, a time-of-flight mass spectrometer based on principles previously described has been constructed with two major modifications to facilitate appearance potential measurements, such as an axial electron beam is pulsed through an ionization chamber utilizing techniques of Fox, et al., and a gated ion detector is employed to integrate the resolved ion current from successive cycles.
Journal ArticleDOI
Mass Measurements with a Magnetic Time-of-Flight Mass Spectrometer
TL;DR: In this article, a mass spectrometer was used to measure the time of flight of ions for a number of complete revolutions in a magnetic field, and the precision as tabulated is estimated from the consistency between independent runs.
Journal ArticleDOI
Magnetic Electron Multipliers for Detection of Positive Ions
Abstract: Two designs of 15‐stage electron multiplier wherein focusing from one beryllium copper dynode to the next occurs in crossed electric and magnetic fields have been developed particularly for detection of weak beams or pulses of positive ions in magnetic fields. One, with dynodes ⅜ in. wide, is usable in fields between about 250 and 460 oersteds while the other, with dynodes ⅛ in. wide, is usable in fields between about 300 and 1100 oersteds. It appears likely that, by using still narrower dynodes, such multipliers can be constructed to operate in fields of several thousand oersteds. Advantages of these designs over previously described multipliers employing crossed fields are the use of about half the number of insulated plates and less tendency, because of uniformity of the electric field, for breakdown and noise, due to ion feedback, to occur. The uniformity of the electric field also allows quite reliable calculation of the spread in transit time. From this it is concluded that, with a modified collecti...
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