| 摘要 |
PURPOSE:To obtain the same good quantifying accuracy with respect to both a high concn. specimen and a low concn. specimen, by making the relative ratio of a bright line variable corresponding to the concn. of the specimen. CONSTITUTION:A lighting circuit Lp performs the lighting of a hollow cathode lamp HCL and the current value In thereof is variable and can be arbitrarily set up to the max Ip corresponding to the concn. of the specimen. A switch S1 is turned ON during a period when the hollow cathode lamp HCL emits a narrow bright line spectrum and the output of a preamplifier PA at that time is sampled. Similarly, a switch S2 is turned ON during a period when the hollow cathode lamp HCL emits a wide bright line spectrum and the output of the preamplifier PA at that time is sampled. A subtraction circuit SB performs the calculation of a predetermined formula and, in a data processing part SP, data of (output of logarithmic amplifier L1-output of logarithmic amplifier L2) is multiplied by appropriate function to calculate and display the absorbancy of the specimen. By this method, by making the current value in large, a S/N ratio is enhanced even in the high concn. region of the specimen and the concn. of the specimen can be measured with high accuracy.
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