Digital linearization provides an accurate mass scale for sector type mass spectrometers

Abstract. PTRwid is a fast and user friendly tool that has been developed to process data from proton-transfer-reaction time-of-flight mass-spectrometers (PTR-TOF-MS) that use HTOF time-of-flight mass-spectrometers from Tofwerk AG (Switzerland). PTRwid is designed for a comprehensive evaluation of whole laboratory or field based studies. All processing runs autonomously and whole laboratory or field campaigns can, in principle, be processed with a few mouse clicks. Unique features of PTRwid include (i) an autonomous and accurate mass scale calibration, (ii) the computation of an "Unified Mass list" that – in addition to an uniform data structure – provides a robust method to determine the precision of attributed peak masses, and (iii) fast data analysis due to well considered choices in data processing.

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MASS SPECTRA AND DISSOCIATION PATTERNS OF TELLURIUM CLUSTERS USING POSITIVE AND NEGATIVE SECONDARY-ION MASS SPECTROMETRY

Surface Review and Letters ◽

10.1142/s0218625x96001042 ◽

1996 ◽

Vol 03 (01) ◽

pp. 577-582 ◽

Cited By ~ 5

Author(s):

H. ITO ◽

T. SAKURAI ◽

T. MATSUO ◽

T. ICHIHARA ◽

I. KATAKUSE

Keyword(s):

Mass Spectrometry ◽

Secondary Ion Mass Spectrometry ◽

Cluster Ions ◽

Mass Spectrometers ◽

Scanning Method ◽

Ion Mass Spectrometry ◽

Cluster Ion ◽

Sector Type ◽

Fragmentation Patterns ◽

Secondary Ion

Size distribution of positive and negative tellurium clusters in the size range from 2 to 56 atoms was investigated by secondary-ion mass spectrometry (SIMS). Cluster ions were produced by the 12-keV Xe+ ions bombardment of a sample tellurium sheet and were mass-analyzed using sector-type double-focusing mass spectrometers. It was found that a discontinuous variation of cluster-ion intensity appeared at specific numbers of n. These numbers were 5, 8, 12, 15, 19, and 23 for positive clusters and 6, 10, 13, and 16 for negative clusters. The dissociation pattern was also investigated by an acceleration-voltage scanning method. It was found that Te2, Te5, and Te6 fragmentation events occurred at a large probability. Observation of specific fragmentation patterns suggested the existence of nonsequential fragment channels.

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Methode der massenspektroskopischen Dispersionsbestimmung

Zeitschrift für Naturforschung A ◽

10.1515/zna-1953-0503 ◽

1953 ◽

Vol 8 (5) ◽

pp. 293-305

Author(s):

Josef Mattauch ◽

Ludwig Waldmann

Keyword(s):

Field Strength ◽

Photographic Plate ◽

Mass Scale ◽

Binding Energies ◽

Mass Spectrometers ◽

Methods Of Evaluation ◽

Special Cases ◽

Order Of Magnitude ◽

Actual Mass ◽

The Ideal

Even in the most carefully built mass-spectrograph, one cannot rely on the ideal massscale when measuring isotopic weights with highest precision, as is necessary for the calculation of nuclear binding energies. Instead, the actual mass-scale in the neighbourhood of a “line” of unknown mass (line on a photographic plate or peak of a curve recording voltage, etc.) has to be ascertained with the help of neighbouring lines of known masses simultaneously recorded and measured (dispersion lines). The approximation of the mass-scale and the evaluation of the unknown line can be done in a clear and general way by the use of Lagrange′s method of interpolation (§ 1 and 2). — However, Lagrange′s approximation without any further assumption would not be sufficient if one has at one′s disposal only a few dispersion lines widely separated, as is the case especially in the range of light masses. Here one has to make partial use of the knowledge of the ideal mass-scale; this is outlined in detail for the special cases of one and of two dispersion lines. In certain cases one will have to use up to three dispersion lines (§ 3). — Furthermore, it is not sufficient to ascertain the mass-scale with the help of a set of dispersion lines in a certain range of the plate (or of the voltage, etc.) at a particular value of the field strength of the deflecting magnet (or of a similar parameter) in order to evaluate an unknown line which subsequently has been brought into this range by varying the field strength; because the dispersion of an apparatus depends always slightly on the field strength (f. i. on account of the unavoidable saturation phenomena of the iron). The order of magnitude of this effect has been estimated from experiments (§ 4). — Finally, there is given an account of the ideal mass-scales of all existing mass-spectrographs, including recent precision mass-spectrometers and a discussion of the methods of evaluation used up to the present time (§ 5 and 6).

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