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Hitachi High-Technologies GLOBAL

When a magnet is set in an atomization section to apply a magnetic field to the atomic vapor, the absorption spectrum of the atomic vapor will be split, showing the polarization property. On the other hand, the background (BKG) is not affected by the magnetic field, showing neither a split nor the polarization property. It is the Zeeman correction method which uses this phenomenon.

For the component of the light source polarized parallel to the magnetic field, "π component atomic absorption + BKG absorption" is observed. However, only "BKG absorption" is observed for the component polarized vertically to the magnetic field. (Since the σ component, which causes atomic absorption is shifted from the measurement wavelength, it does not cause atomic absorption.)

A:"What are features of the Zeeman correction method?"

  1. Since t is a double beam measurement system in which the light parallel to the magnetic field (apparent atomic absorption line) and the light perpendicular tothe magnetic field (BKG absorption line for subtraction) traverse the same optical path (one beam is split into two, with the polarizer), there are no drifts, leading to astable baseline.
    The D2 (deuterium lamp) correction method and the self-absorption method measure two kinds of beams with different characteristics. Accordingly, the system is called a single beam measurement system. Since this system does not measure two kinds of beams under the same conditions, the baseline may drift.
  2. The Zeeman correction method can cover the whole wavelength region.

  • D2 correction method
    1. Only the ultraviolet region can be corrected.
    2. The electric heating furnace atomization method features poor performance.
  • Self absorption method
    1. Some elements cannot be measured.
    2. Since the hollow cathode lamp is lit irregularly, deterioration is promoted.

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