GFAA spectrometry instruments have the following basic features : 1 . a source of light ( lamp ) that emits resonance line radiation; 2 . an atomization chamber ( graphite tube ) in which the sample is vaporized; 3 . a monochromator for selecting only one of the characteristic wavelengths ( visible or ultraviolet ) of the element of interest; 4 . a detector, generally a photomultiplier tube ( light detectors that are useful in low-intensity applications ), that measures the amount of absorption; 5 . a signal processor-computer system ( strip chart recorder, digital display, meter, or printer ).
12.
This quality factor produces a passive resonance line of rms = 5 Hz, which is eight orders of magnitude smaller than the atomic linewidth of the Ne line ( a 1 : 1 mixture of the two isotopes and has a gain bandwidth of about 2.2 GHz ) . ( Note that for example in regular pendulums the Q is of the order of 10 3 and in wristwatch-type quartzes it is of the order of 10 6 . ) The active ring further reduces the linewidth by several orders of magnitude, and increasing the measuring time may additionally decrease the linewidth by many orders of magnitude.
