Xenon lamp diffuse mode

Even though the lamp looks like a conventional arc lamp, it has been optimized to run in the so-called hot-spot mode . This discharge mode is characterized by the appearance of an extremely small plasma spot close to the cathode surface, in contrast to the typical diffuse arc shape of the common xenon lamps (refer to Figure 3.1). The plasma contraction is substantially achieved by selection of sophisticated materials for the anode and cathode rods, a short electrode distance (< 1 mm), an increased xenon pressure (about... 

Figure 3.1 Photo of a xenon short-arc lamp operating in hot-spot mode (left) and diffuse mode...

The wavelength-dependent spectral radiance of the hot-spot xenon lamp is depicted in Figure 3.2 for different distances from the cathode in relation to the prominent emission lines of some hollow eathode lamps. In addition, a comparison of its spectral radiance to a commercial xenon lamp operating in diffuse mode as well as a conventional D2-lamp is shown in Figure 3.3. 

Figure 3.3 Comparison of the wavelength-dependent spectral radiance of (a) the xenon short-arc lamp operating in hot-spot mode (XBO 301, 300 W, GLE Berlin, Germany) (b) a commercial xenon lamp operating in diffuse mode (L 2479, 300 W, Hamamatsu, Japan) (c) a conventional D2-lamp (MDO 620, 30 W, Heraeus, Germany)...

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