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The xenon-arc lamp is chosen more often than other continuous sources for use with AAS

because of the relatively high intensity of its emitted radiation.

Advantage of the use of a continuous sources

The primary advantage of the use of a continuous source is that a single lamp can be used
at different wavelengths for the analysis of many elements. The xenon-arc lamp can be used for

nearly all analyses that are usually done by AAS because its emissive band overlaps at least one
of the commonly used absorptive lines of nearly all the analyzed elements. Automated multi-

element AAS could probably best be done with continuous source.

Disadvantages of the use of continuous sources
The major disadvantages of the use of continuous sources for AAS are the relatively low

emissive intensities within the absorptive bandwidths of atom and the requirement for high
quality monochromator. Even the relatively high intensity of xenon-arc lamp is usually

considerably less intense within the absorptive bandwidth of a particular atom than that of an
appropriate line source.

A high quality monochromator is required with a continuous source in order to limit the

band of wavelength that are used in the study as much as possible. Even with the good
monochromator, the wavelength band that is used with continuous source is broader than the

absorptive band of the atoms in the cell. For those reasons, line rather than continuous source are
generally provided with commercial spectrophotometers.

I.3.1.2. LINE SOURCES
They emit highly intense radiation only in the wavelength range corresponds to the

absorptive band for a particular atom or group of atoms. They do not emit a continuum of
radiation.

The primary advantage of line sources is the high intensity that is achieved within a narrow

bandwidth.

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