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H1 Halogen Automotive Replacement Light Bulbs.Conventional Oven Replacement Light Bulbs.BA15D Appliance Replacement Light Bulbs.to accurately measure the respective emission lines. For example, as the 365 nm emission line is a triple line (three emission lines in close proximity), the spectral bandwidth must be 0.5 nm max. The 254 nm, 365 nm, 436 nm, or 546 nm emission lines can be used for the calibration but care is required with the slit width (spectral bandwidth) used during measurements. Low-pressure mercury lamps are available in versions that use the emitted ultraviolet lights directly, or as so-called fluorescent lamps that use a fluorescent material to convert the wavelength to a different wavelength.Ī spectrophotometer uses the mercury emission lines to calibrate the displayed wavelength values. 4 shows the spectral distribution of a low-pressure mercury lamp. The low-pressure mercury lamp is a discharge lamp designed to have a low mercury vapor pressure (100 Pa max.) when lit to efficiently emit the mercury resonance lines (254 nm or 185 nm).įig. Halogen lamps are often used in general spectrophotometers but xenon lamps are used in cases where a high light intensity is required (such as spectrofluorophotometers), due to their high brightness.įig.4 Spectral Distribution of a Low-Pressure Mercury Lamp 3) (5) Low-Pressure Mercury Lamp Overall, the xenon lamp is inferior to the halogen lamp and deuterium lamp in terms of cost and output fluctuations. The xenon lamp exhibits a similar spectral distribution to sunlight and produces a continuous spectrum from the ultraviolet to the near-infrared, as shown in Fig. However, the alternating-current type permits the use of a compact, low-cost lighting device, as no current rectification is required. Therefore, the tungsten evaporates more easily than with the direct-current type. As the electrodes of an alternating-current type electrode alternately become the cathode and anode, both electrodes are the same size. As the anode becomes particularly hot, the anode of a direct-current type xenon lamp is made larger than the cathode to increase its thermal capacity. If the electrodes become too hot, the tungsten electrode material can evaporate and adhere to the tube wall, resulting in a loss in brightness. Xenon lamps are categorized as directcurrent or alternating-current types, according to the lighting method. 3 Emission Intensity Distribution of a Xenon Lamp 2) (3) Xenon Lamp (Xenon Arc Lamp)Ī xenon lamp is a discharge light source with xenon gas sealed in a bulb. 5) and can be used for wavelength calibration of the spectrophotometer.įig. Of these, the spectra at 486.0 nm and 656.1 nm are particularly strong (see Fig. Multiple emission spectra also exist in the range at 400 nm and above. However, the low degree of attenuation toward the longwavelength end permits use of light above 400 nm. The use at the long-wavelength end is limited to about 400 nm. 2 shows examples using synthetic quartz and UV glass. The window material limits its use at the short wavelength end.įig. The deuterium lamp has a short emission wavelength of 400 nm, or less. However, it is one of the few continuous spectrum light sources that is stable in the ultraviolet range. As it uses a hot cathode to achieve stable and reliable arc discharge, approximately 10 sec for preheating is required before starting the discharge.Ī deuterium lamp requires a large and complex power supply, making it more expensive than a halogen lamp. As such, they many of the conditions required for a spectrophotometer light source.įig.2 Emission Intensity Distribution of a Deuterium Lamp 1) (2) Deuterium LampsĪ deuterium lamp is a discharge light source with several hundred Pa deuterium sealed in a bulb.

Halogen lamps are stable over time, offer a long service life (approx. The usable wavelength range is 350 nm to 3500 nm, but this is affected by the color temperature. 1 shows the light intensity distribution at 3000 K color temperature. It also restricts blackening of the tube wall, due to adhering evaporated tungsten, to create a light source that remains bright over long periods.įig. Consequently, the bulb containing the filament of a normal incandescent lamp is filled with an inert gas to prevent evaporation of the tungsten.Ī halogen lamp contains a halide as well as the inert gas to create the halogen cycle (Reference 2) that returns evaporated tungsten to the filament, resulting in a long lamp life. The tungsten used as the filament material evaporates at high temperatures. Similar to a normal incandescent lamp, a halogen lamp filament heats up and emits light when a current flows through it. Fig.1 Emission Intensity Distribution of a Halogen Lamp(3000K) (1) Halogen Lamps

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