Jpn. J. Appl. Phys. 14 (1975) pp. 1361-1370 |Next Article| |Table of Contents|
|Full Text PDF (1093K)| |Buy This Article|
An Ion Counting Method with Multichannel Pulse Height Analyser for High Sensitive Mass Spectrometry
Science and Engineering Research Laboratory, Waseda University
1Institute for Nuclear Study, University of Tokyo
(Received April 11, 1975)
A newly developed ion counting method in mass spectrometry is described. This method makes use of analog switch, so as to make the output pulse height from the secondary electron multiplier linear in (m/e)1/2 of the ions. When fed to a multichannel pulse height analyser (MC-PHA), these output pulses produce a histogram which directly represents the mass spectrum. The new method makes possible a rapid scanning of the magnetic field in a mass-spectrometer.
In order to overcome problems of counting loss of ions, which is caused mainly by MCPHA, it is required to change the accumulation rate of pulses in MCPHA especially for the most abundant isotopes. For this purpose, we designed a “window sensitivity attenuator", in which the incoming rate of ions to the electron multiplier is converted into its 1/2n by using a series of binary counters.
The new counting method was applied to the isotopic measurement on magnesium with samples of inclusions of the Allende Meteorite, and the results are presented.
- N. R. Daly:
Rev. Sci. Instrum. 31 (1960) 264[AIP Scitation].
- N. R. Daly:
Rev. Sci. Instrum. 34 (1963) 1116[AIP Scitation].
- E. W. Blanth, W. M. Dreager, J. Kirschner, H. Liebl, N. Müller and E. Taglaner:
J. Vac. Sci. Technol. 8 (1971) 384[AIP Scitation].
- Leonard A. Dietz:
Rev. Sci. Instrum. 36 (1965) 1763[AIP Scitation].
- G. W. Barton, L. E. Gibson and L. F. Tolman: Anal. Chem. 32 (1960) 1599.
- R. G. Ridley, R. Munro, W. A. P. Young, R. Hayes, R. W. D. Hardy and H. W. Wilson: Advances in Mass Spectrum (The Institute of Petroleum, London, 1966) No. 3, 553.
- G. R. Hertel:
J. Chem. Phys. 48 (1968) 2053[AIP Scitation].
- H. R. Ihle and A. Neubert: Internat. J. Mass Spectrom. Ion Phys. 7 (1971) 189.
- H. Miyake and M. Michijima: Mass Spectroscopy 19 (1971) 110 [in Japanese].
- R. Gensho, S. Takeuchi and M. Honda: Mass Spectroscopy 20 (1972) 211 [in Japanese].
- J. W. White:
Rev. Sci. Instrum. 38 (1967) 187[AIP Scitation].
- D. N. Shramm, F. Tera and D. J. Wasserburg: Earth Planet. Sci. Letters 10 (1970) 44.