| 摘要 |
An atomic absorption spectrophotometer having a source, e.g., a hollow cathode lamp, of spectral radiation of a selected narrow band of wavelengths optically directed along an axis through an electrothermic sample atomizer and a field stop to a photoelectric detector. The sample atomizer is subjected to a substantially unipolar AC electromagnetic field having flux lines directed transversely to said axis to effect Zeeman splitting of the radiation into two orthogonally polarized components pi and sigma . Disposed in the optical path between the atomizer and detector is a stationary beam-splitting polarizer prism oriented so as to transmit the sigma polarized component and block the pi component. Mirrors are used exclusively in the optical systems so as to minimize the effect of dispersion and stray light. An electromagnet, used to generate the electromagnetic field, is connected to the AC power line in series with the diode and has a small capacitor connected across its coils. This causes the magnetic field at the sample atomizer to vary sinusoidally from a maximum value of one polarity to a very small value of the opposite polarity. The polarizer prism is of unique design in which one polarization passes through undeviated on the optical axis while the other is diverted to one side on the other. The ray passing through the prism along the optical axis is uniquely depolarized upon exiting. A field stop is located between the prism and the atomizer and restricts the field of view of the prism to an angle less than or equal to its restricted field of view, excludes blackbody radiation of the furnace, and limits the aperture at the source. |
