Mercury xenon arc lamp

As a result of these differences in dependence on source intensity, fluorescence methods are generally one to three orders of magnitude more sensitive than methods based on absorption. Mercury arc lamps, xenon arc lamps, xenon-mercury arc lamps, and lasers are typical fluorescence sources. Monochromators and transducers are typically similar to those used in absorption spectrophotometers, except that photomultipliers are invariably used in high-sensitivity spectrofluorometers. Fluorometers and spectrofluorometers vary widely in sophistication, performance characteristics, and cost, as do absorption spectrophotometers. Generally, fluorescence instruments are more expensive than absorption instruments of corresponding quality. 

The light source is commonly a tungsten filament lamp (covering the visible region of the spectrum, typically 340-8(X) nm) or a deuterium discharge lamp for the UV region (200-350 nm). For some applications, more intense sources such as a xenon or xenon/mercury arc lamp, or even lasers, may be required. 

Figure 77 Emission spectra of (A) xenon-mercury arc lamp, (B) deuterium arc lamp, and (C) deuterium hollow cathode lamp. (Adapted from M. S. Epstein and T. C. Rains, Anal. Chem., 1976, 48, 528)...

These devices are called liquid crystal light valves (LCLVs), and projection LC display systems used in the LCLV are shown in Fig. 6.27 [93]. In drawing figures, the option of YAG Nd lasers, GaAs semiconductor lasers, or Ar or He-Ne gas lasers can be used. As a projection light source, the option of halogen, xenon, mercury arc lamps, or the like can be used. The size of the screen can be as large as 2.5 m X 2.5 m. 

Photoirradiation and ESR Measurements. The samples of cellulose and cellulose derivatives were packed uniformly into clear fused Suprasil quartz tubes (O.D. 4 mm), which did not produce any ESR signal during the irradiated sequences. The quartz tubes containing the samples were evacuated to a constant pressure (10 6 mm Hg) and sealed. The source of ultraviolet irradiation was a high pressure mercury-xenon compact arc lamp (Conrad Hanovia type 901 BOOH, 200 W) which... 

New xenon plasma fiashlamps, which generate significant light intensity in the deep UV region (<250 nm) are better suited for direct photolysis than conventional mercury-based UV lamps. Spectra of xenon flash lamps are different than those of the mercury arc lamps and in the range of IR to the UV-C region (300-200 nm) (23). The spectral emission of the xenon flash lamps depends on the current density and the plasma temperature. 

The fluorescence intensity is directly proportional to the intensity of the source radiation, Iq. In theory, the fluorescence intensity will increase as the light source intensity increases, so very intense light sources such as lasers, mercury arc lamps, or xenon arc lamps are frequently used. There is a practical limit to the intensity of the source because some organic molecules are susceptible to photodecomposition. 

Exposure to sunlight for periods up to 600 h gave values of k equal to 15.4 x 10 and 13.3 X 10 for jute and cotton, respectively, in units of reciprocal DP per hour exposure. Exposure to artificial sources of UV light such as a mercury arc lamp or a xenon arc lamp gave lower values of k than for sunlight, but again jute and cotton were similar. With the... 

Any ellipsometer (see Figure 1) consists of five elements (1) a light source, (2) a polarization state generator (PSG), (3) a sample, (4) a polarization state detector (PSD), and (5) a light detector. The light source can be a monochromatic source, such as from a laser, or a white light source, such as from a xenon or mercury arc lamp. The PSG and... 

Figure 7 (A) Spectrum of a 1000 W tungsten-halogen lamp. Reproduced with permission from Oriel Corporation (1994) Oriel 1 4 Catalog, Volume II. (B) Spectrum of a 200 W mercury arc lamp. Reproduced with permission from Oriel Corporation (1994) Oriel 1994 Catalog, Volume II. (C) Spectrum of a 150 W xenon arc lamp. Reproduced with permission from Oriel Corporation (1994) Oriel 1994 Catalog, Volume II.

Excitation spectra of D API and Hoechst 3 3 342 are too short for most of the lasers and mirrors that are supplied with commercially available laser scanning microscopes, although these dyes can be imaged in conventional fluorescence microscopes with Xenon or Mercury arc discharge lamp or when using HeNe laser/UV system or multiple photon microscopy... 

A diagram of the author s original spectrofluorimeter is shown in Figure 3. The light source, S, was either a 1 kw. compact source mercury vapor lamp, or for the measurement of fluorescence excitation spectra, a 375 w. xenon arc. The required frequency of exciting light was isolated by means of a Hilger 1)247 quartz prism monochromator, Mj, and... 

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