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Applications of X-Ray Photoelectron Spectroscopy and Secondary Ion Mass Spectrometry in Characterization of Polymer Blends
Published in Gabriel O. Shonaike, George P. Simon, Polymer Blends and Alloys, 2019
Chi-Ming Chan, Jingshen Wu, Yiu-Wing Mai
In a SSIMS experiment, the surface is bombarded with a primary ion beam of low current density (typically 10−11 to 10−8 A/cm2) to minimize damage. The sputtered material consists largely (>99%) of secondary neutral species, with a small fraction (< 1 %) of secondary positive and negative ions. The basic principle of SIMS is shown schematically in Fig. 2. The mass of the ions is measured by a mass analyzer. The quadrupole mass analyzer, the combined electrostatic and magnetic sector analyzer, and the time-of-flight mass spectrometer are analyzers used in SIMS systems. These mass spectrometers have different mass ranges and mass resolutions. The mass resolution (M/ΔM) of a spectrometer is a measure of the ion separating ability of the instrument, where M is the mass of the peak and ΔM is the full width at half-maximum peak height of the peak. The time-of-flight mass spectrometers are very popular in organic material analysis because they offer several advantages: a high transmission over the whole mass range, an unlimited mass number, a high mass resolution, and a simultaneous detection of all masses.
Electrical, Physical, and Chemical Characterization
Published in Robert Doering, Yoshio Nishi, Handbook of Semiconductor Manufacturing Technology, 2017
Dieter K. Schroder, Bruno W. Schueler, Thomas Shaffner, Greg S. Strossman
Sufficient mass separation of the secondary ion signals is required so that the ion species monitored during a depth profile are in fact due to the dopant. The ability to separate two atoms or molecules of the same charge at mass m, which differ in mass by the amount Δm is described by the mass resolution as mass resolution=mΔm A higher mass resolution value of a spectrometer implies better ability to unambiguously measure and identify the element or molecule of interest. For example, the analysis of 11B in silicon requires only a mass resolution of 11 because the closest interfering signal is due to 12C. Higher mass resolution is required for separating interferences between species like 31P+ and (30SiH)+ or (28Si2)+ and 56Fe+, which occur in the SIMS analysis of silicon.
Measurement of Partial Pressure at Vacuum Conditions
Published in Igor Bello, Vacuum and Ultravacuum, 2017
Mass Resolution: One of the fundamental parameters of mass analyzers is the spectral mass resolution. The mass resolution is the capacity of a mass spectrometer to differentiate between two ion masses that slightly differ. As many literary sources indicate, the definition of mass resolution is somewhat incoherent. The mass resolution is mostly defined as recommended by the International Union of Pure and Applied Chemistry, which is given by the expression ρR=MrΔMr where ΔMr is the resolving power. Thus, in accordance with this definition, the higher value ρR corresponds to the higher mass resolution.
Electron detachment dynamics of the iodide-guanine cluster: does ionization occur from the iodide or from guanine?
Published in Molecular Physics, 2020
Rosaria Cercola, Kelechi O. Uleanya, Caroline E. H. Dessent
UV photodissociation experiments were conducted in a laser-interfaced amaZon SL (Bruker Daltonics) ion-trap mass spectrometer as described previously [33,34]. The clusters were generated by electrospraying a solution of guanine (1 × 10−4 mol dm−3) mixed with droplets of t-butyl ammonium iodide (1 × 10−2 mol dm−3) solution in deionised water (1 × 10−4 mol dm−3). To increase the solubility of guanine in water, the solution was made alkaline with droplets of a 30% ammonium hydroxide solution. All chemicals were purchased from Sigma Aldrich and used without further purification. Typical operating conditions of our mass spectrometer provide mass resolution better than 0.3 amu.