| 摘要 |
A process and apparatus for calibrating a particle counter is described. The process comprises the steps of forming a vector gas flow by an aerosol of particles of the same grain size, developing ions in the vector gas with both sign by a bipolar charger, certain particles being electrically charged to a stationary charge state in which the distribution of the number of charges fixed to each particle follows a Gaussian law (Gunn or Boltzmann), passing the charge aerosol into a mobility selector to attract the charged particles to electrodes therein and classify them as a function of the numbers p of their elementary electrical charges e and allowing the electically neutral particles to escape, collecting the neutral particles and passing the neutral particles into the particle counter to be calibrated, the particles counter displaying a value N'o; counting the values of Np and Np+1 of the number of particles of charges pe and (P+1)e fixed by the selector and calculating by the formula <IMAGE> the number No representing the number of neutral particles supplied to the counter and comparing N'o with Np. An apparatus using above process to separately pick-up the charged particles with a view to count the numbers Np and Np+1 contains a particle counter in which particles of the same grain size are produced comprising a cylindrical case containing an annular cylindrical bipolar charge space and a mobility selector linked with the charge space and are superimposed manner within the cylindrical case.
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