A low pressure of argon in the lamp insures that the line width from the hollow cathode lamp is less than the line width of the absorbing species. AA Hollow Cathode Lamps Recommended Operating Conditions Operation A number of factors affect successful lamp operation. Collisions of excited state sputtered atoms with argon atoms will lead to broadening of the output of the hollow cathode lamp and potentially lead to the same problem described above with the use of a continuum source. The pressure of the argon is low to minimize collisions of argon atoms with sputtered atoms. Hollow Cathode Lamps working totally depends. With this understanding we can ask why the hollow cathode lamp has a low pressure of argon filler gas. Answer (a) :Hollow Cathode Lamps are ideal source of spectral lines that are used for testing in laboratories. Therefore, hollow cathode lamps, which emit intense narrow lines of radiation specific to the element being analyzed, are needed for atomic absorption measurements. Reducing the slit width on a continuum source to a level that would provide a narrow enough line to respond to atomic absorption would reduce the power so that it would not be much above the noise. The radiation passing through the instrument alternates between the deuterium continuum and the analyte source and then subtracts background absorption from the total. The problem with reducing the slit width is that it reduces the number of photons or source power reaching the sample. 1) Koirtyohann and Pickett 7 developed the first automatic background technique using a combination of a CS, such as a deuterium lamp, and a hollow cathode lamp (single LS). What is the problem with reducing the slit width of the monochromator to get a narrower line? Atomic absorption line superimposed onto the overall output of a continuum source/monochromator system.
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