SU480142A1 - Spectral high-intensity lamp - Google Patents

Description

one

The invention relates to gas discharge devices, in particular to spectral high-intensity lamps emitting narrow spectral lines of various chemical elements. Such light sources are used in atomic absorption and atomic fluorescence analysis equipment and in other spectrophotometric devices.

Various designs of spectral lamps with a combined (glow and arc) discharge are known. In particular, lamps are known in which the cathode is made with a cavity into which an element or chemical compound is introduced.

However, the creation of lamps emitting the spectra of precious, rare-earth, alkaline, alkaline-earth and radioactive elements is associated with great technological difficulties.

Known lamps do not provide savings of these elements and their uniform entry into the discharge.

The purpose of the invention is to eliminate the drawbacks of the known spectral lamps. This is achieved by the fact that in a spectral high-intensity lamp having a thermal cathode, an anode and at least one cylindrical glow discharge cathode coaxially located relative to the positive pole, the glow discharge cathode is made of two parts.

entering one into the other and forming deaf cavities filled with chemical elements or their compounds and communicating with each other and with the discharge space

through the annular groove. It is advisable in the discharge space to make a cylindrical recess with a diameter smaller than the annular groove and larger than the diameter of the outlet openings of the cathode.

Pa figs. 1 shows the proposed lamp; in fig. 2 shows a cathode assembly in a section rotated at an angle of 45 °. Spectral high-intensity lamp

has a cylindrical glass cylinder 1 with a window 2 for the radiation to exit, made of a material that is transparent in the visible and near-infrared spectral region, and filled with argon to a pressure

4 mmHg Art. Anode 3, having the form of a disk with a central opening for radiation emission, thermal cathode 4 of indirect heating and a cathode assembly consisting of two heat-resistant electrical insulating sleeves 5, a cathode

a glow discharge assembly 6, an electrically insulating tube 7 and two mica disks 8, are assembled on an eight-pin flat glass rod 9, the leads of which are placed in electrically insulating tubes 10. For convenience and reliability of connecting the lamp to the power source, it is equipped with an octal base 11 under the standard lamp panel.

The glow discharge cathode (Fig. 2) consists of two parts 12 and 13 of cylindrical shape, partially enclosing each other and forming eight deaf symmetric cavities 14 of the same section, arranged parallel to the generator of the cylindrical cathode. In the cavity 14, glass ampoules 15 with alkaline elements are placed. All eight cavities 14 communicate with each other and the discharge space through an annular groove 16. The magnitude of the groove is determined depending on the filler element and ranges from 0.1 to 2 mm. For the elements of the alkaline group, it is 0.3 mm. The discharge space of the cathode has a cylindrical recess 17 with a diameter smaller than the annular groove and larger than the diameter of the outlet openings 18 of the cathode. This prevents liquid metal from escaping from the cathode cavity during lamp operation.

In order to make reliable electrical contact between the two parts 12 and 13 of the glow cathode and prevent liquid metal from flowing out onto the outer surface of the cathode, the junction of both parts on the outer surface is covered with a nickel foil 19 that covers both parts of the cathode and welded by spot welding around the perimeter.

In order to prevent the glow discharge from spreading to the external surface of the cathode and the convenience of mounting, two identical electrically insulating sleeves 20 are mounted with their ends.

Between the glow-discharge cylindrical cathode 6 and the anode 3 (Fig. 1) is ignited

under the action of intense ion bombardment of the cathode and its thermal heating in the discharge space, pairs form in the form of neutral atoms of the filler elements, which are excited in

the positive column of an arc discharge burning between the thermal cathode 4 and the anode 3 and passing through the discharge cavity.

Subject invention

Claims (2)

1. Spectral high-intensity lamp having a flask with a window for radiation output, an anode, a thermal cathode, and a glow discharge cathode with cavities for the placement of chemical elements or their compounds, characterized in that, in order to save chemical elements and ensure their uniform entry into the discharge, the glow discharge cathode is made of two cylindals entering one into another which form closed cavities filled with a chemical element or its compounds and communicating with the discharge space through the annular groove. 2. The lamp according to claim 1, characterized in that, in order to prevent chemical elements from flowing out of the discharge space during operation of the lamp, it has a cylindrical recess with a diameter smaller than the annular groove and larger than the diameter of the outlet openings of the cathode . .-- B M- If ig 1 Fig 2