The main application fields of spectrum light source are low-pressure mercury lamp, low-pressure sodium lamp, atomic spectrum lamp, helium lamp, hydrogen lamp, hydrogen arc lamp, amalgam lamp and microwave electrodeless spectrum lamp.
Atomic spectrum lamp
, also known as hollow cathode lamp, is a glow discharge light source with hollow cathode discharge. The cathode of this lamp is cylindrical, and the cathode area of the lamp emits light evenly and brightly. When working, positive ions strongly bombard the cathode, so that the metal on the cathode surface is sputtered, and the sputtered atoms enter the discharge area, so that the lamp radiates the spectrum of metal elements. If the cylindrical cathode is made of a single pure metal, the spectrum of the single element can be obtained. For metals that are expensive, difficult to shape, low in melting point and easy to oxidize, copper and nickel can be used as base metals to make a cylinder, and then a thin layer of precious metals can be embedded; A certain amount of the required metal can also be added to the inner cylinder by embedding method or evaporation film method. For spectral lamps whose cathodes are various metal elements, alloy cathodes or compound cathodes with several single metals arranged together are often used.
atomic spectrum lamp has the advantages of high radiation spectral line intensity, high stability and narrow spectral line width, which can be used as the length standard of spectral analysis and interference measurement of trace elements, and can also be used to measure wavelength. This kind of lamp has more than 6 specifications.
Hydrogen lamp and Helium lamp
are glow discharge light sources with stable energy radiation in hydrogen spectrum (wavelength 431.4nm, 486.1nm and 656.3nm) and helium spectrum (wavelength 76.5nm and 587.6nm) respectively. It can be used as accessories for various optical instruments such as interferometers and refractometers. The discharge tube is filled with high-purity hydrogen or helium, and the lamp has an additional part that can increase the gas storage volume to maintain a constant air pressure, thus making the discharge more stable. The discharge part is made into a capillary with an inner diameter of 2 ~ 3 mm to concentrate the radiation luminosity.
hydrogen arc lamp
is an arc discharge light source with a hot cathode. The glass shell is made of Shi Ying glass, filled with high-purity hydrogen, and can radiate a continuous spectrum with a wavelength of 18-4 nm. Hydrogen arc lamp is one of the basic light sources for studying molecular structure.
amalgam lamp
Mercury is used as the base metal, and a proper amount of metal vapor arc discharge light source made of cadmium and zinc is filled. In addition to the characteristic spectral lines of mercury, the characteristic spectral lines of cadmium and zinc (wavelengths 643.8nm, 636.2nm, 632.5nm, 631.6nm, 546.1nm, 58.5nm, 481.nm, 435.8nm and 44.7nm, etc.) located between mercury spectral lines are radiated. When amalgam lamp is used to calibrate the wavelength of spectrometer, it is unnecessary to use other monochromatic light sources, and it can make the wavelength calibration of spectrometer more convenient and correct. It is widely used in metallurgical, medical, physical and chemical tests.
microwave electrodeless spectrum lamp
A light source that uses microwave to induce electrodeless discharge to emit light. The lamp is filled with several hundred pa of inert gas and some volatile pure elements or metallic and nonmetallic halides. Its working frequency is about 1MHz, and its radiation spectrum is almost entirely atomic line spectrum without interference background. This lamp has simple structure, low cost, stable performance and reliable use, and is an ideal radiation spectrum in atomic fluorescence spectrometry.