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Saturday, August 8, 2020 | History

2 edition of electron multiplier suitable for measuring ion currents. found in the catalog.

electron multiplier suitable for measuring ion currents.

James Alexander Mair

electron multiplier suitable for measuring ion currents.

by James Alexander Mair

  • 144 Want to read
  • 20 Currently reading

Published .
Written in English

    Subjects:
  • Physics Theses

  • Edition Notes

    Thesis (M.A.), Dept. of Physics, University of Toronto

    The Physical Object
    Pagination1 v.
    ID Numbers
    Open LibraryOL21261509M

      Gas electron multiplier (GEM) is a two-dimensional (2D) gas detector which was developed during the end of the s and was then broadly applied in high energy physics experiments [].Recently, the GEM was used in tokamaks for soft x-ray radiation (SXR) which may be applied in the future for the international thermonuclear experimental reactor (ITER machine) [2–6].Author: Erzhong Li, H. Qu, H. Qu, L. Hu, F. Cordella, F. Cordella, G. Claps, G. Claps, D. Pacella, D. Pacell. Electron multipliers are used in surface analysis instruments to boost the detected signal to a level where it can be amplified and processed into data. For Auger Electron spectrometers and X-ray photo electron analyzers the detected signal are electrons. Secondary ion spectrometers detect ions. In the s electron multipliers were made out.

    Agilent's high quality Electron Multiplier for ICP-MS is an important accessory in an effective, precision system. electron multipliers capable of converting incoming energy packets (UV, X-ray, electron, ion, etc.) into highly amplified (gains in excess of 10) output pulses offers an appealing approach to upper-atmosphere and outer-space measurement and analysis problems. Where prolonged experi-.

    Electrospray ionization mass spectrometry is a desorption ionization method. Desorption ionization methods can be performed on solid or liquid samples, and allows for the sample to be nonvolatile or thermally unstable. This means that ionization of samples such as proteins, peptides, olgiopeptides, and some inorganic molecules can be performed. 4. Discrete type electron multiplier transducers can provide current gain upto which of the following? a) 10 2 b) 10 5 c) 10 7 d) 10 Answer: c. Explanation: Discrete type electron multiplier transducers can provide current gain upto 10 2. Upto 20 dynodes need to be used for this purpose. 5.


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Electron multiplier suitable for measuring ion currents by James Alexander Mair Download PDF EPUB FB2

The Agilent Electron Multiplier converts incident ions into an amplified electric current in a stable, precision process. The low noise currents created are used to measure the ion signal from sample in a wide variety of ICP-MS applications.

How Electron Multipliers Work An electron multiplier is used to detect the presence of ion signals emerg-ing from the mass analyzer of a mass spectrometer. It is essentially the “eyes” of the instrument (Figure 1).

The task of the electron multiplier is to detect every ion. It is recommended that one should refer to the abundance of an ion, to the intensity of an ion beam, and to the height or area of a peak. Sources: Orange Book, 2 nd ed., p. [ Terms ] [ Book.

The novel ion detector overcomes the performance barriers on traditional electron multipliers and will provide the most suitable results to meet users’ requirements.

Structure Electron Multiplier R features an off-axis structure and a Faraday cup, required for ion detection in Quadrupole mass spectrometers that can make accurate.

A method for measuring the gain of an electron multiplier is presented that does not require direct measurement of input current. The method is based on the relation between the electron multiplier suitable for measuring ion currents.

book. current and the R.M.S. noise current at the output of an electron multiplier. Errors arise if shot noise is not the dominant noise source in the system. An apparatus for measuring a first pressure within a space, a total pressure in the space being in at least a portion of a range of pressures between a lower limit above about millitorr and an upper limit of about millitorr, the apparatus comprising: means for producing an ion related to the first pressure; an electron multiplier in communication with the space having an input end that receives the ion and an Author: Stephen M.

Penn, C. Bruce Mcallister. The development of electronic techniques for television during the s yielded a device of extraordinary sensitivity for measuring small electron beams—namely, the secondary electron multiplier.

Although originally invented for the amplification of the tiny currents from a photocathode, it soon proved to be an excellent detector for ion beams with a sensitivity sufficient to record the arrival of single ions. The most common detector in mass spectrometry is the electron multiplier; this amplifies the weak ion beam signal greatly, yielding gains of up to the order of 10 liers can be either a discrete dynode type or a continuous dynode, generally known as a channel electron multiplier or discrete dynode electron multiplier comprises a series of Be–Cu alloy dynodes arranged.

The gain of an electron multiplier can most simply be defined as the ratio of the output electron current to the input ion current at a specified second dynode voltage. The output current is not directly measurable without auxiliary test equipment, but it can be inferred from the height of an ion.

Electron multipliers are perhaps the most common detectors in modern mass spectrometers due to their exceptionally high gain and low noise. A single ion entering the front of the multiplier can result in upwards of one million electrons exiting the back.

detector in quadrupole and ion trap mass spec trometers and find many applications in magnetic sector instruments as well. Early Developments The idea for an electron multiplier based on an integrated device combining secondary emission and a resistive chain dates from ; however, it was not until suitable materials.

Abstract THE letter from Prof. Bay 1 gave details of the application of electron-multipliers to the measurement of photons and electrons emitted in vacuo.

Experiments on similar lines have been carried out in this laboratory with the object of using electron-multipliers for measuring small ionization currents due to any type of radiation.

An electron multiplier is a vacuum-tube structure that multiplies incident charges. In a process called secondary emission, a single electron can, when bombarded on secondary-emissive material, induce emission of roughly 1 to 3 electrons. If an electric potential is applied between this metal plate and yet another, the emitted electrons will accelerate to the next metal plate and induce secondary emission of still more electrons.

An electron multiplier is used to detect the presence of ion signals emerging from the mass analyser of a mass spectrometer. It is essentially the ‘eyes’ of the instrument.

The task of the electron multiplier is to detect every ion of the selected mass passed by the mass filter. A method for characterization of electron multiplier-based pulse counting systems is presented.

Specific attention is paid to measurement of the counting system dead time. The systems discussed here are typically used to measure the abundance of ions passing through a mass spectrometer. A method for the determination of dead time by measurement of at least two isotopic ratios of an element Cited by: Mass Spectrometry: Detectors Review Article (PDF Available) in Annual Review of Chemical and Biomolecular Engineering 3(4) October with 6, Reads How we measure 'reads'.

The ion detector of a mass spectrometer includes an accelerating electr 34, 38 disposed between the spectrometer discharge shutter 6 and a secondary electron multiplier The electrode 10 is selectively energized by a high positive or negative voltage opposite the initial polarity of the ions by a source Thus, a positively energized electrode draws in and accelerates negative ions Cited by: A modification that permits the utilization of an air‐stable, continuous‐dynode electron multiplier that can be used either as an ion‐counting or as an ion current measuring device without jeopardizing the photoplate ion detection capability of the high‐resolution mass spectrometer is by: 3.

The external bias option allows for current / voltage comparisons with the users’ own low-noise DC power supply. The +5kV version can float up to +/- 5kV and is used for measuring the output directly from electron multipliers or biased collector arrays.

Microsoft Windows 10 data logging and graphing software is provided. With an overall cross-sectional area of about mm{sup 2}, reproducible current measurements can be carried out down to some nanoamperes. The Faraday cup is used to measure ion beams in an energy range up to 25 keV and beam currents up to 10 mA.

The current is determined on the basis of the voltage drop at selected metal film resistors. Electron Multipliers ION DETECTION IN ICP-MS using Active Film Multipliers Kevin Hunter, ETP Scientific, Auburn, MA Reprinted from Atomic Spectroscopy, Jan/FebROLE OF THE ELECTRON MULTIPLIER IN AN ICP-MS Figure 1 shows the functional layout of an ICP-mass spectrometer system.

Broadly speaking, the mass spectrometer can be described.Abstract: Recent applications of the electrostatic, electron multiplier tube to problems which require the measurement of very small currents or the counting of single ions or electrons are described in this paper.

The characteristics of secondary electron emitting surfaces suitable for use in multiplier tubes are discussed in the first section. The next section is devoted to recently Cited by: Continuous Dynode Electron Multiplier. A Faraday cup detector is standard with SRS RGA systems which allows partial pressure measurements from to 5 × Torr.

For increased sensitivity and faster scan rates, an optional electron multiplier is offered that detects partial pressures down to 5 × Torr.

This state-of-the-art macro.