RU2247440C2 - Spectroscopic gas-discharge lamp for atomic absorption - Google Patents

Abstract

FIELD: hollow-cathode spectroscopic gas-discharge lamps for atomic-absorption analyzers.

SUBSTANCE: proposed lamp that may be found useful not only for atomic-absorption equipment but also for atomic-fluorescent analyzers has uviol glass window for outlet of rays transparent in ultraviolet spectrum that accommodates anode, insulating sleeve, and hollow cathode, as well as main discharge cavity in the form of cylinder open on one end and made of material whose spectrum should be obtained. Hollow cathode is provided with additional discharge cavities communicating with main cavity to form single discharge cavity with common burning area. Diameters of additional discharge cavities are equal to diameter of main cavity. Glow discharge is persistent between annular anode and main and additional discharge cavities. Sputtering products escaping from all cavities enter main discharge cavity wherein they are excited due to collision with electrons and radiate enhanced-intensity spectral resonance lines. This occurs due to enlarged discharge surface. The more additional discharge surfaces the higher is radiation intensity.

EFFECT: enhanced radiation intensity, enlarged functional capabilities of lamp.

2 cl, 2 dwg

Description

The present invention relates to a class of spectral gas-discharge light sources intended for use in atomic absorption analysis apparatus. A known design of a spectral gas discharge lamp with a hollow cathode emitting spectra of various chemical elements, containing a flask with an uviolium window for the emission of radiation transparent from the ultraviolet part of the spectrum, an anode, an electrical insulating tube and a hollow cathode having a main discharge cavity in the form of a cylinder open on one side and made of material, the spectrum of which is necessary to obtain / 1 /. The anode has the form of a pin or cylinder located in close proximity to the open cavity of the cathode. The hollow cathode is placed in an insulating tube with a smooth (0.2-0.3) mm gap. The lamp is filled with inert gas neon at a certain pressure. When such a lamp is connected to a power source between the anode and the discharge cavity of the cathode, a glow discharge is ignited. Under the influence of intense ion bimberdation, the cathode material is atomized. Sputtering products in the form of neutral atoms fall into the gas discharge, are excited there upon collision with electrons and emit lines belonging to the spectrum of this element, the radiation intensity of which is used in atomic absorption analysis devices. The disadvantages of lamps of this design should include a small amount of radiation intensity of the resonance lines. To increase the radiation intensity inside the cavity of the bare cathode, additional elements are inserted in the form of a wire or foil of the element of the hollow cathode / 2 /. This led to a slight increase in the combustion area, and, accordingly, to an increase in the radiation intensity of the resonance lines. However, the radiation intensity was still insufficient. Moreover, not every metal can have additional elements. For metals such as sodium, potassium, arsenic and other additional elements can not be made. Therefore, to increase the radiation intensity of the resonance lines, other technical solutions must be sought.

The technical result of the invention is to increase the radiation intensity of the resonance lines. To achieve a technical result in a spectral gas discharge lamp for atomic absorption, containing a flask with a uviole window for radiation exit and an anode located therein, an electrical insulating tube and a hollow cathode having a main discharge cavity in the form of a cylinder open on one side and made of material, the spectrum which must be obtained, is made with additional discharge cavities communicating with the main cavity in a single discharge cavity with a total combustion area. The diameters of the additional discharge cavities are equal to 0.8-1.2 of the diameter of the main cavity. Due to this, it was possible to combine all the hollow cathodes into one common hollow cathode with the sum of the combustion areas of all the discharge surfaces. At the same time, it was possible to obtain a significant increase in the combustion areas of the gas discharge, as well as the number of neutral atoms in the main discharge cavity, the hollow cathode, and, accordingly, an increase in the radiation intensity of the resonance lines on the radiation exit axis. The more additional discharge cavities communicating with the main discharge cavity, the larger the burning area of the glow discharge, and accordingly, the greater the intensity of the study of resonance lines.

Figure 1 shows the construction of a gas discharge spectral lamp for atomic absorption in the context. Figure 2 shows a hollow cathode in cross section AA. The lamp is a glass cylinder 1 of a cylindrical shape with a flat window 2 for the exit of radiation transparent in the ultraviolet part of the spectrum. Anode 3 is made of nickel wire. It has the shape of a ring.

The hollow cathode 4 has a main discharge cavity 5 in the form of a cylinder, open on one side and made of material, the spectrum of which must be obtained, installed in a glass tube 6 with a small gap (0.2-0.3) mm so that the glow discharge does not penetrate to the outer surface of the cathode. The hollow cathode is made with additional discharge cavities 7, the diameters of which are equal to 0.8-1.2 of the diameter of the main cavity. The anode, hollow cathode, and glass tube are assembled on a glass leg 8 using molybdenum leads 9. The lamp is filled with an inert gas to the required pressure.

When such a lamp is connected to a power source between the anode 3 of the main discharge cavity 5 and all discharge cavities 7 of the cathode 4, glow discharges in an inert gas are ignited. Spray products both from the main discharge cavity and from additional discharge cavities in the form of neutral atoms enter the gas discharge of the main cavity, are excited there upon collision with the elements, and emit spectral lines whose radiation intensity leaves the lamp through the flat window 2.

In the process of the lamp operation, the sprayed particles, flying from additional discharge cavities to the main discharge cavity, add intensity to the total radiation of the lamp and reduce the self-rotation of the main radiation line.

Thus, the presence of additional discharge cavities in the full cathode leads to a substantial increase in the radiation intensity of the resonance lines. The more additional discharge cavities communicate with the main discharge cavity, the more radiation intensity will be received from the lamp.

The proposed invention is new.

A new design of the hollow cathode and the lamp as a whole is proposed. Made an inventive step.

The hollow cathode of the lamp is made with additional discharge cavities communicating with the main discharge cavity into a single discharge cavity with a total combustion area. The diameters of the additional discharge cavities are equal to 0.8-1.2 of the diameter of the main cavity. The invention is industrially applicable in the production of spectral lamps to increase the intensity of the study of resonance lines and improve the quality characteristics of the lamp.

Literature

1. KP Kureichik et al. "Gas-discharge light sources for spectral measurements", Minsk, Universitetskoye Publishing House, 1987, pp. 32-42.

2. USSR No. 1552255, cl. H 01 J 61/09 1988

Claims (2)

1. Spectral discharge lamp for atomic absorption, containing a flask with a uvole window for the exit of radiation transparent in the ultraviolet part of the spectrum, and the anode located therein, an electrical insulating tube and a hollow cathode having a main discharge cavity in the form of a cylinder open on one side and made from a material whose spectrum is to be obtained, characterized in that the hollow cathode is made with additional discharge cavities communicating with the main discharge cavity into a single discharge cavity with a common plane sparing combustion, while the diameters of the additional discharge cavities are equal to (0.8-1.2) the diameter of the main cavity of the cathode. 2. The spectral discharge lamp according to claim 1, characterized in that the additional discharge cavities are made 2, 4, 6, 8.

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