As power to the lamp increases, the bandwidth of the sputtered elements broadens, and analytical sensitivity reduces. For other applications, currents exceeding the recommended maximum may be acceptable. However, for many elements this maximum is related to lamp life. At excessive currents the cathode can melt or metal vapor can be flashed onto the front window. Next column Fluorescent lamps.
Fluorescent lamps are bulky and of relatively low brightness.
The atoms are excited by high energy collisions with electrons. The scientific use of these lamps is limited to irradiation of large surfaces, such as in environmental growth chambers. The gaseous elements are excited by thermal processes. Another source in this category is the deuterium lamp. Electrodeless discharge lamps.